Palagrudža Geologie

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ABSTRACT

Velika Palagrua (Pelagosa) is the largest island of the Palagrua archipelago (central Adriatic Sea, Croatia). Despiteits minute size the island bears a certain geological interest being the only exposed piece of land in the central part(Mid-Adriatic ridge) of the common Adriatic foreland of the Apenninic and the Dinaridic orogenic domains. Thelitho-, bio-, and chemostratigraphic (strontium and sulphur isotopes) characteristics of the sedimentary units, alongwith tectono-structural and geomorphic characteristics of the island, are described in this paper. The oldest alo unitis composed of highly deformed siliciclastics containing gypsum, and carbonates of Middle Triassic (Ladinian) age.This unit represents a transitional fluvial-to-shallow marine, occasionally evaporitic environment, typical of the Mid-dle Triassic rifting phase of the Adriatic microplate. Soft and strongly deformed alo unit deposits are found alonga probably still active, WNWESE striking, subvertical, oblique-slip fault that crosses the entire length of the island.

The alo unit is probably in diapiric contact with the Lanterna unit, poorly defined as Late Triassic, and character-ized by dolomite with chert and dolomite breccia, presumably deposited in a transitional platform-to-basin environ-ment of an evolving Adriatic basin. The Lanterna unit deposits are capped by Miocene biocalcarenites of the Sala-mandrija unit over an almost perpendicular discordance, possibly representing an unconformity, suggesting that anearly deformational phase preceded a Miocene marine transgression. Talus, landslide deposits, and humic soil makeup the cover of the bedrock sedimentary succession, and they represent the ultimate phase of emersion of the island,which probably occurred during Pliocene(?) to Quaternary times. An active neotectonic regime of the central Adri-atic is evidenced by present-day seismicity, while recent uplifting of the island is shown by the presence of remnantsof pebbly palaeobeach deposits, marine (erosional) straths, and cyanobacterial supratidal encrustations (pelagosite)currently observed at various elevations above mean sea level.

Keywords:carbonate platform, basin, Triassic, Neogene, Mid-Adriatic ridge, recent uplift

Geologic reconnaissanceof the island of Velika Palagrua

(central Adriatic, Croatia)

Tvrtko Korbar1, Alessandro Montanari2, Georg Koch1, Sandro Mariani2,

Don DePaolo3, Alexandra V. Turchyn4, Mirjana Mikni1 and Vlasta Tari5

1 Croatian Geological Survey, Department of Geology, Sachsova 2, HR-10000 Zagreb,Croatia; ([email protected])

2 Osservatorio Geologico di Coldigioco, 62021 Apiro, Italy3Department of Earth and Planetary Science, University of California, Berkeley,

CA 94720-4767-U.S.A.4 Department of Earth Sciences, Cambridge University, Downing St., Cambridge,CB2 3EQ, United Kingdom

5Exploration Department, INA-Naftaplin, ubieva 29, HR-10000 Zagreb, Croatia

doi: 10.4154/gc.2009.07

Geologia Croatica 62/2 7594 15 Figs. 2 Tabs. Zagreb 2009

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1. INTRODUCTION AND PREVIOUS WORK

Velika Palagrua (Pelagosa in Italian) is a small island in thecentral Adriatic Sea, the largest within the Palagrua archi-pelago (Fig. 1). The island is placed within the commonAdriatic foreland of the Apennines and the Dinarides, 57 kmfrom the Gargano promontory to the south, and 60 km fromthe Island of Lastovo to the northeast. The distance from themainland as well as steep slopes and a hostile rocky coast,makes access to the island rather difficult. A handful of pub-lished studies be counted since the first geological and palae-ontological reconnaissance of the island of Palagrua wascarried out by STUR (1874), at about the time when the Austri-ans were building the monumental lighthouse on the highestpoint of the island. Palagrua was then revisited by STACHE(1876) and, independently, by MARCHESETTI (1876).

Further geological studies were carried out by BOI-EVI et al. (1965). The authors proposed a Middle Jurassicage for the basal dolomite formation based on the presence

ofLithothamnion, and a Miocene age for the biocalcareniticlimestone at the top of the succession, according to the fo-raminiferal and mollusc association. The stratigraphic bed-rock succession of Velika Palagrua is capped by Pliocene(?)to Quaternary talus breccias and humic soil.

The authors of the explanatory notes for the basic geo-logical map sheet (KOROLIJA et al., 1977) proposed a Ju-rassic age for a siliciclastic unit with gypsum exposed nearthe beach of alo (see Fig. 2 for location), based on a gen-eral lithological analogy with the Komia complex on theisland of Vis (at the time considered to be of Jurassic age),and stratigraphic relationships with the underlying dolomites

containing chert nodules of proposed Late Jurassic age. KO-ROLIJA et al. (1977) argued for the Late Cretaceous age ofthe overlying biocalcarenites exposed in a quarry pit at Sala-mandija (see Fig. 2 for location).

SOKA et al. (1980) identified the foraminifera Mean-drospira pusillafrom a small outcrop of siliciclastic-evap-oritic rocks near alo containing sandstones, gypsum, clay,and silt, which, along with results from mineralogical analy-

ses, indicated an Early Triassic or possibly even older (LatePermian) age. The authors, in agreement with the interpreta-tion of KOROLIJA et al. (1977), viewed this siliciclastic-evaporitic unit at alo as a diapir. The diapiric setting of thePalagrua block was suggested by GRANDI et al. (2002)following seismo-stratigraphic interpretation. GRANDI et

al. (2002) also referred the broader area of the Palagrua ar-chipelago to the Jurassic to Palaeogene Adriatic basin do-main.

Gypsum often occurs in Upper Permian to Triassic for-mations throughout the Alpine domain, and represents shal-low water evaporitic environments during an early subsid-ence phase of the Adriatic microplate, which was probablyattached to the African continental crust (e.g. CHANNELLet al., 1979; BOSELLINI, 2002). However, the stratigraphicposition of Adriatic evaporites and associated rocks is oftendoubtful, mainly due to their chaotic setting.

From the few geologic reports cited above it appears that

Palagrua has a geological complexity and overall impor-tance much bigger that its own minute size, which defini-tively demands more detailed study. The results of a prelim-inary geological survey are reported here, which highlightsthe stratigraphic and structural complexity of this island.While some uncertainties still remain in the accurate chron-ostratigraphic assessment of the main rock formations, struc-tural and geomorphic features exposed in the island offernew evidence for a past and recent history of geodynamicevents.

2. REGIONAL GEOLOGICAL

AND TECTONIC SETTINGSPalaeogeographically, the central Adriatic area is consideredto represent a Jurassic to Palaeogene Adriatic basin enclosedbetween the Apulia carbonate platform to the southwest(Italy), and the Adriatic (Dalmatian) carbonate platform tothe northeast (Croatia) (ZAPPATERRA, 1994; BOSELLINI,2002; GRANDI et al., 2002; TARI, 2002; VLAHOVI etal., 2005). At present, the succession of mostly pelagic for-

Figure 1:Simplied geotectonic map of the wider Adriatic region, and location of the Palagrua archipelago.


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Korbar et al.: Geologic reconnaissance of the island of Velika Palagrua (central Adriatic, Croatia) Geologia Croatica

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mations of the central Adriatic Basin is covered by thick Neo-gene siliciclastic deposits (BERTOTTI et al., 2001). Theseformations are known from boreholes and seismic profiles(e.g., GRANDI et al., 2002, and references therein), andPalagrua is the only place in the whole region where someof these units are exposed above sea level.

BOGNAR (1995) proposed that Palagrua represents apop-up structure, which consists of a fault-bounded frag-ment of continental crust that is being pushed laterally andvertically by compressional tectonic forces. In other words,Palagrua is uplifting due to the head-on collision betweenthe converging Apenninic and Dinaridic orogenic systems(Fig. 1), and, for this very reason, it is subject to seismic ac-tivity.

Through modelling GPS measurements of crustal veloc-ity along a transverse profile across the southern Adriaticmicroplate and south-central Dinarides, BENNETT et al.(2008) assumed a NNE dipping thrust fault, which surfaces

along the offshore of southern Dalmatia, between the islandsof Vis and Palagrua, not far north of Palagrua. BENNETTet al. (2008) argued for SW-migrating deformation in an ac-tive fold-and-thrust belt as a consequence of uninterruptedsubduction of the southern Adria mantle lithosphere beneathEurasia since the Eocene. In this tectono-seismic scenario,Palagrua is located on the footwall of the thrust not far fromits line of emergence to the north, and its present horizontalmovement toward the NE in respect to fixed Eurasia is about5 mm/yr (BENNETT et al., 2008).

Recent regional seismic-stratigraphic data (GRANDIet al., 2002) suggest that diapirism probably contributes to

the current crustal uplifting along two WNWESE divergentreverse faults (suggesting transpression), which delimit thePalagrua submarine rise Palagrua high (BERTOTTI etal., 2001) or Mid-Adriatic ridge (GRANDI et al., 1997;GELETTI et al., 2008), in the southern and northern off shoreof the island. GELETTI et al. (2008) argued for a Mioceneonset of the diapirism, according to seismostratigraphic in-terpretations, whereas the related deformations continue todate.

At present, the central Adriatic is seismically active (e.g.HERAK et al., 1996; GRANDI et al., 2002; CHIARABBAet al., 2005; RIDENTE & TRINCARDI, 2006). The most

important seismic event in recent times was represented bythe 1988 swarm, which started in February 1988, and endedearly in 1989. More than 100 quakes > 3M were recordedduring this period, with epicenters spread over an area about30 km long (in a NESW direction) and 20 km wide (HERAKet al., 1996). The largest earthquake of this sequence reacheda magnitude of 5.3, and its epicenter was located 38 km SEof Palagrua, with a focal mechanism indicating slightly ob-lique reverse faulting with an EW strike (RIDENTE &TRINCARDI, 2006). This is consistent with the general de-formation on strike-slip and thrust faults resulting in NESWshortening along the eastern coast of the Adriatic Sea (BATT-AGLIA et al., 2004).

In summary, the Mid-Adriatic ridge belongs to the Adri-atic foreland, and its origin is related to combined strike-slip

faulting and vertical salt movement. Palagrua is probablyplaced at the topmost part of an active diapiric structure char-acterized by a very deep root.

3. SEDIMENTARY UNITS AND TECTONICS

The sedimentary units exposed at Velika Palagrua are de-scribed according to direct observations of key outcrops andtheir distribution in our original geologic map (Fig. 2), whichhighlights the remarkably complex geology of this tiny is-land. However, it should be stressed that a more precise agedetermination, as well as more detailed stratigraphic and tec-tonic relationships between the sedimentary units, requiresfurther research. Nevertheless, the units are described belowand are organized according to their proposed stratigraphicposition.

3.1. alo unit

An outcrop of stratified yellowish siltstones and green-greyclaystone associated with gypsum is located in the southerncentral part of the island, about 50 m west of a fishermansshack at the western end of alo beach (Location 1, Fig. 2).These rocks comprise a stratigraphic succession from a basalhomogeneous green-gray clay unit, to a lens of fracturedwhite gypsum about 1.5 m thick, overlain by a finely strati-fied clay-rich siltstone unit containing disperse gypsum, andterminating with a second horizon of green-gray clay-richsiltstone (Fig. 3A). Fragments and whole shells of microgas-tropods, and small vertebrate bones were observed in a sam-ple of green-gray clay/claystone from the alo outcrop, but

have not so far yielded a taxonomic determination.The succession is covered by a rockfall of dolomite

boulders. Apart from the fractured gypsum, where green-gray clay fills the fractures (Fig. 3B), this outcrop appearsundeformed, with regular, parallel bedding constantly dip-ping 32NE.

The green-gray clay of the alo unit is also exposed inthe lower part of a ravine at Picokare, about 200 m furtherwest (Fig. 4A). Some metres above this outcrop, a packageof thin-bedded, beige-yellowish dolomite layers are exposed,with a dip of 27NW. Unfortunately, the contact between theclay and this thin-layered unit is not exposed, but it seems

that the alo unit occupies this part of the island, from thefisherman shack at alo beach to the Picokare gully, and itis covered by boulder rock fall and south-dipping coarse talus(see Figs. 2 and 4A). On the other hand, the contact betweenthe alo unit clay and the Lanterna unit dolomite with chert(see section 3.2.) to the west of the Picokare ravine, is wellexposed, and it is represented by a sharp discordance (Fig.4A). Practically, the thick-bedded dolomite layers with chertof the Lanterna unit (unit A, see below), which dip steelpyto the SW, are cut by a flat and smooth undulatory surface,with a dip of about 45 toward the E. The clay of the alounit is found resting on top, against this surface (Fig. 4B).We are still uncertain on the exact nature of this discordance,which does not appear to be a simple angular unconformity.We do not exclude that the flat discordance surface is actu-


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ally a deformed fault plane, as some oblique slickenside stri-ations on the smooth surface suggest, and that the alo unithas been put in place against the already tilted Lanterna do-lomites by the combined action of oblique-slip faulting anddiapiric uplifting. However, the age relationship between thealo unit and the Lanterna unit is still uncertain (see below),which limits the plausibility of the interpretation for thisrather odd structural situation.

Another key exposure of the alo unit is located on thesoutheasternmost coast of the island, south of a localitycalled Jonkova Njiva (Fig. 5A). As at Picokare, the alo unitrests on top of thick-bedded dolomite layers of the lower partof the Lanterna unit (i.e., unit A in the legend of Fig. 2). Therocks, which include marly siltstones containing dispersenodules of gypsum, and a few layers of stromatolitic lime-stone, are strongly deformed (Fig. 5B). On the north side of

Figure 3:A) Outcrop of the siliciclastics and gypsum of the alo unit west of the alo beach; B) close up of the fractured gypsum with greenish-gray claylling in the cracks.

Figure 2:Geologic map and synthetic stratigraphic column of the island of Velika Palagrua. Sampling locations on inserted map (not in scale): 1 sam-ples Pal5 and Pal6; 2 samples Pal22 and Pal23; 3 sample Pal14; 4 sample Pal16; 5 sample Pal12D; 6 samples Pal10 and Pal13.

A B


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this outcrop a WNWESE striking subvertical oblique-slipfault puts the alo unit in contact with strongly deformed,medium-thick bedded dolomites and dolomite breccias of thepresumed upper part of the Lanterna unit (unit B). This faultis probably the continuation of the oblique-slip fault that dis-sects the whole length of the island from Stara Vlaka on theNW, to the southeastern point of Jonkova Njiva, where alounit rocks occur in a strongly deformed fault zone.

A similar situation is found on the south side of the StaraVlaka cove (Figs. 2 and 6), where strongly deformed thin-bedded dolomites and green-grey clay are found within thehighly tectonized zone of the same oblique-slip fault (Fig.6A and B).

3.1.1. Palynostratigraphy of the alo unit

To overcome the age uncertainty of the alo unit, and assessits palaeoenvironmental and biostratigraphic attributes, a de-tailed palynological study of a number of soft rock samples

from various outcrops throughout the island, was undertaken.Sample Pal5(alo unit gypsum, W of alo beach, lo-

cation 1 on Fig. 2) is palynologically barren.

Sample Pal6(alo unit silty claystone, W of alo beach,location 1 on Fig. 2). Palynoflora of the sample Pal6 (AP-PENDIX 1 and Fig. 7) is represented by a diverse and well-preserved assemblage of predominantly sporomorphs andmay well be correlated to the palynoflora of the Europeanand Circum-Mediterranean independently dated Ladiniansections (VISSCHER & BRUGMAN, 1981; WARRING-TON, 2002; SCHULZ & HEUNISCH, 2005).

In the Alpine region of the Dolomites in Italy, the paly-noflora of sample Pal6 corresponds to the palynologicalsecatus dimorphusphase of VAN DER EEM (1983). Thistype of palynoflora has been described from sections of south-eastern Switzerland (SCHEURING, 1978) and the Dolomites(BLENDINGER, 1988; HOCHULI & ROGHI, 2002), as wellas from Liechtenstein,western Austria (BRHWILER et al.,2007) and Hungary where it has been designated as meierischeuringiiphase (GCZN & ORAVECZ-SCHEFFER,1993; KOVCS et al., 1994). Thesecatusdimorphusphaseconcours with the ammonoid gredlerizone and archelauszone (VAN DER EEM, 1983; BRUGMAN, 1986), which,according to BRACK et al. (2005), are Late FassanianEarlyLangobardian in age. Among the stratigraphically significantsporomorphs that are shared between the secatus dimor-

phusphase and the palynoflora of sample Pal6,Heliosac-cus dimorphushas a range within thesecatus dimorphusphase whilst Camerosporites secatus,Duplicisporites gran-

Figure 4:A) Panoramic view of the Picokare ravine from the south, show-ing discordance (?diapiric contact) between the alo unit clay and the sub-vertical, thick-bedded dolomites with chert of the Lanterna unit A, bothcapped by stratied talus; B) Close up (from above) of the contact betweenextremely deformed greenish clay of the alo unit and the dolomite of theLanterna unit A.

Figure 5:A) Panoramic view of the outcrop of the alo unit near JonkovaNjiva, and B) close up of the discordant (?diapiric) contact with the under-lying Lanterna unit A.

A

B

A

B


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ulatus, Sellaspora rugoverrucata,Kyrtomisporis erveiandBrachysaccus neomundanusfirst appear at the base of theearly Fassanian ammonoid curioniizone (Earliest Ladinian),i.e.plurianulatussecatusphase (VAN DER EEM, 1983;BRUGMAN, 1986). According to BRHWILER et al. (2007),the first appearance of C.secatusandD.granulatusis higherand corresponds to the base ofsecatus dimorphusphaseof the ammonoidgredlerizone. Last appearance of Cannan-aropollis scheuringiiis at the top of Late Langobardian (Lat-est Ladinian)secatus vigensphase which correspond tothe ammonoid regoledanuszone (VAN DER EEM, 1983;BRUGMAN, 1986). The last appearance of this taxon hasbeen found at the top of the Ladinian also in other parts ofthe Alpine facies (SCHEURING, 1978; GCZN & ORA-VECZ-SCHEFFER, 1993; KOVCS et al., 1994). Severaltaxa of the Pal6 palynoflora also occur in other Alpine sec-tions, e.g.Haberkornia parva/gudatiandPodosporites ami-cus, ranging approximately with the secatus dimorphusphase, andDoubingerispora filamentosa,which first appearsat the base of the Ladinian. Sample Pal6 also contains thestratigraphically significant sporomorphs Staurosaccites qu-adrifidus, Ovalipollis pseudoalatusandPartitisporitesspp.,which first appear at the base of theplurianulatusnovimun-

danusphase of the ammonoidNevaditessp. (=secedensis)zone, previously considered as early Fassanian (earliest La-dinian) by VAN DER EEM (1983) and BRUGMAN (1986).

After the acceptance of the GSSP for the base of the Ladi-nian stage at the base of the ammonoid curioniizone (BRACKet al., 2005), theplurianulatus novimundanusphase rep-resents the latest Anisian palynofloral development. Theplu-rianulatus novimundanusphase contains, in the lower part,the Late Anisian sporomorphs Stellapollenites thiergartiiand

Dyupetalum vicentinense,and its top is defined by the lastappearance ofIllinites chitonoidesand Concentricisporitesplurianulatus(BRUGMAN, 1986). Since these sporomorphshave not been identified in the sample Pal6, the presenceof S. quadrifidus, O.pseudoalatusandPartitisporitesspp.alone suggests an age not older then earliest Ladinian. Con-sidering the highest range of the sample Pal6 palynoflora,the lack ofEnzonalasporites vigens, Weylandites magmus,and Lueckisporites cf.singhii, which first appear at thebase ofsecatus vigensphase of the ammonoid regoledanuszone, treated as Late Langobardian (Latest Ladinian) (VANDER EEM, 1983, BRUGMAN, 1986; BROGLIO LORIGA etal., 1999), suggests an age not younger than Latest Ladinian.

In the Germanic facies, the palynoflora of sample Pal6corresponds to the palynological record of the Lettenkohlesuccessions (Lower Keuper). In Poland, OROWSKA-ZWO-LISKA (1983) designated the Lettenkohle palynoflora asrepresenting theHeliosaccus dimorphusZone. In Germany,several palynological zones, phases and subphases have beendescribed, which allowed correlation to the Alpine timeequivalents (REITZ, 1985; HEUNISCH, 1986; VAN DENBERGH, 1987; BRUGMAN et al., 1988; VAN BERGEN &KERP, 1990; BRUGMAN et al., 1994; BEUTLER et al.,1996; HEUNISCH, 1999). The palynoflora of the Letten-kohle successions in France correspond to the correlativesin other parts of the Germanic facies (ADLOFF et al., 1984;COURTINAT & RIO, 2004).

The palynoflora of the Lettenkeuper has been dated bas-ed on both independent control and palynological correlationwith the Alpine record. The palynofloral record from south-ern Germany, which is enhanced within the iliacoides di-morphussub/phase (VAN DEN BERGH, 1987; BRUGMANet al., 1988) and perforatus dimorphusphase of (VANBERGEN & KERP, 1990; BRUGMAN et al. (1994), corre-sponds to the Alpinesecatus dimorphusphase.

In the Circum-Mediterranean region of Spain, the paly-noflora of sample Pal6 corresponds to thesecatus meierisubphase of BESEMS (1983) which represents the lowerpart of the Camerosporites secatusphase (VISSCHER &KRYSTYN 1978; VISSCHER & VAN DER ZWAN, 1981;VAN DER EEM, 1983) and is similar to the palynoflora ofLettenkohle as described by GARCIA GIL & DIEZ (2006).In Libya, ADLOFF et al. (1986) reported on a palynoflora,which they correlate, to the Alpine secatus dimorphusphase of VAN DER EEM (1983). In Israel, ESHET (1990)described the palynoflora from the ammonoid controlled sec-tion which has been assigned to the Podosporites amicusZone corresponding in many elements to the European cor-relatives. Syrian subsurface sections revealed a palynoflora

which YAROSHENKO & BASH IMAM (1995) and LUIet al. (2003) compare to the palynofloras of the Circum-Med-iterranean and European Ladinian correlatives.

Figure 6:A) panoramic view of the western point of Velika Palagrua look-ing east with the indications of the geologic features described in the text;B) The exposure at Stara Vlaka cove showing the fault contact between atectonized alo unit and the dolomite breccia of the Lanterna unit B, andthe discordant contact with the thick-bedded dolomite of the Lanternaunit A. The dolomite breccia of Lanterna unit B is covered by a pebbly pal-aeobeach deposit resting below a talus slope.

A

B


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Figure 7:Palynomorphs and palynofacies of the alo unit claystone sample Pal6 (location 1 on Fig. 2). Autochthonous Ladinian:1)Kyrtomisporis ervei,

2)Doubingerispora lamentosa, 3)Cannanoropollis scheuringii, 4)Heliosaccus dimorphus, 5)Lunatisporites acutus, 6)Striatoabieites balmei, 7)Triadisporaplicata, 8)Ovalipollis pseudoalatus, 9)Staurosaccites quadridus, 10)Haberkornia parva, 11)Duplicisporites verrucosus, 12)Camerosporites secatus, 13)Aulis-porites astigmosus, and 14)Veryhachiumsp., 15) Palynofacies. Reworked Lower Triassic:16)Densoisporites nejburgii and17)Endosporites papillatus.


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Along with the authochtonous Ladinian palynoflora,sample Pal6 also contains reworked sporomorphs (APPEN-DIX 2, Fig. 7/16, 17), among which,Endosporites papillatusandDensoisporites nejburgiisuggest reworking from LowerTriassic successions. Several sporomorphs assigned as cf.Lueckisporites virrkiae,Limitisporitessp. and cf.Nuskois-

poritessp. indicate reworking most likely from Permian suc-cessions.

From the palynological point of view, the palynoflora ofsample Pal6 is almost identical to the palynoflora from thesurface sections of the diapiric structure at Komia, the is-land of Vis (BELAK et al., 2005), which has been designatedas the dimorphusInterval Zone and interpreted as Late Fas-sanianEarly Langobardian in age. At the Komia site, BE-LAK et al. (2005) also reported discovery of the dasycladalalgaDiplopora nodosawith a Late AnisianLadinian rangeaccording to GRGASOVI & SOKA (2003) as well as theproblematic taxonPlexoramea cerebriformiswith a Middle

AnisianCarnian range according to GORIAN et al. (2005).At present, the findings ofD. nodosarepresent the stratigra-phycally narrowest independent control of the described pal-ynoflora in the area under consideration.

Sample Pal14(alo unit clay, Stara Vlaka cove, loca-tion 3 on Fig. 2)containsa moderately to poorly preservedpalynoflora, predominantly of sporomorphs, generally sim-ilar to the palynoflora of sample Pal6, and may thereforebe considered Ladinian in age.

Sample Pal22(alo unit stromatolitic limestone, SE ofJonkova Njiva, location 2 on Fig. 2) contains a small amountof degraded palynological organic matter and only a few

poorly preserved bisaccate pollen grains and cf. Camero-sporites secatussuggesting a LadinianCarnian age.

Sample Pal23(alo unit marly siltstones, SE of Jonk-ova Njiva, location 2 on Fig. 2)contains palynoflora similarto Pal14. However, the assemblage is less diverse allowing anage assignment within a wider LadinianCarnian range.

3.1.2. Age of the alo unit

According to the palynostratigraphy reported here (section3.1.1., APPENDIX 1, Fig. 7/115), the alo unit was datedas Middle Triassic in age (Ladinian).

Thealo unit was dated as Lower Triassic by SOKA

et al. (1980), according to the Lower Triassic foraminiferaMeandrospira pusillafound in limestone microlithoclasts ofquartzose calcarenitic sandstones. Unfortunately, neither thesandstones mentioned by Soka and co-workers, nor the mi-crofossils were found within analysed outcrops or elsewherein the alo unit. However, redeposited Lower Triassic paly-nomorphs were found (see chapter 3.1.1., APPENDIX 2, Fig.7/16, 17). Thus, it is suggested that SOKA et al. (1980) re-ported on presumably Ladinian sandstones containing rede-posited Lower Triassic limestone microlithoclasts.

3.1.3. Palynofacies of the alo unit

The composition of the palynological organic matter of sam-ples Pal6, Pal14 and Pal23 is almost identical. SamplePal6 (Fig. 7/15) is characterized by a better preservation

state of the organic matter in respect to other samples. Mostof the organic matter consists of fragments of woody tissue(90%) followed by leaf (cuticle) remains (5%), and palyno-morphs (5%). Opaque clasts of presumably woody tissue (assuggested by the shape of the clasts) are rare (


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ments. Group I is of bryophytic and group J is of pterido-sperm origin while groups KP are of coniferalen affinity,respectively. Groups IP reflect xerophytic plant communi-ties of hinterland vegetation. Group P represents prasyno-phycean algae and group Q coenobial chlorophycean algaewhich reflect freshwater-brackish to intertidal shallow ma-

rine and lagoonal depositional sets. Group Q represents phy-toplankton of marine environments.

The quantitative distribution of the groups within the pal-ynoflora of Pal6 (APPENDIXES 1 and 3) shows that thegroups KP constitute 80% of the whole palynological assem-blage indicating predominantly xerophytic plant communitieswhich suggests semi-arid climate conditions. This may wellbe supported by high frequencies of group L (Ovalipollis/Stau-rosaccites; 26.6%) and group P (Circumpolles; 19.8%), whichare indicators of regional aridity, and a high frequency of bi-saccate pollen (64%) indicating the proximity of xerophyticplant communities of the hinterland vegetation.

3.1.5. Sulphur isotopes of the alo unit gypsum

To separately test the Triassic age for the alo unit, we ana-lyzed the sulfur isotope composition (34S) of selenitic gyp-sum from the outcrop Pal5, (location 1, Fig. 2). Sulfur iso-tope measurements were made both on original evaporiteminerals and on samples that were leached in water and re-precipitated as barium sulfate prior to isotope analysis. Bothreplicates are presented in Table 1. The isotope analyses arein parts per thousand or and the standard is the CanonDiablo Troilite (CDT). The analytical error of the isotopemeasurement is 0.2.

In theory, the 34S of marine gypsum or other sulfate-evaporite mineral should be related to the 34S of global ma-rine sulfate at the time the evaporite formed (IFTAR, 1987).The 34S of global ocean sulfate was distinct in the Miocene(22) from the Permian to Triassic (~10 to 15). Using the34S of an evaporite mineral as a geochronological indicatorcan however be problematic. First, there can be isotope dy-namics associated with evaporating basins; sulfur isotopescan be fractionated during precipitation and progressive eva-poration and this will impact on the 34S of the sulfate in theevaporitic brine. Second, and more problematically, the sul-fate that is used to form the evaporite mineral could comenot from ocean-sulfate but from oxidized hydrogen sulfide(H2S). H2S forms from bacterial sulfate reduction in anoxicsediments and rocks; because of sulfur isotope fractionationduring bacterial sulfate reduction, the H2S formed has a 34Sthat is 10 to 50 lower than the original sulfate. If this H2Smigrates and then oxidizes, the sulfate formed during oxida-tion will also be isotopically light and distinct from sea-

water sulfate. For example, the microcrystalline gypsumslush mass found in the Frasassi caves (Italy) has 34S of13.7, and was likely formed from subaerial reaction be-tween H2S and a lower Jurassic limestone of the CalcareMassiccio Formation (e.g. MARIANI et al., 2007, and ref-erences therein). In this case, the H2S originates from reduc-

tive dissolution of a Triassic anhydrite in the underlyingTriassic Burano Formation.

The sample from Palagrua (GYP) has a similar 34S of11.4, which suggests that the source of the sulfate for thisgypsum is not seawater, but instead reoxidized H2S. If thePalagrua gypsum were precipitated directly from Miocene,Triassic or Permian seawater then we would expect valuessimilar to those typical for marine evaporites. Therefore, wecannot use the 34S of the Palagrua gypsum to place thisunit in the chronological context.

3.2. Lanterna unit

The most widespread rocks found at Palagrua are grey,hard, cryptocrystalline dolomites, all of which make up theLanterna unit. Except for the area covered by humic soil,rock fall, and talus on the northern side of the island and atPicokare, this unit is well exposed on the coastal cliffs allalong the perimeter of the island (Fig. 2), and it includes me-dium- to thick-bedded dolomite and irregular bodies of mas-sive dolomite breccia. However, in many places the rocksare strongly deformed, fractured, and tectonically brecciatedto the point that it is often difficult to discern primary bed-ding. Moreover, dolomitization has also obliterated internalstructures and fossils of the source limestone, which pre-

vents palaeontological age and palaeoenvironmental deter-minations. Nevertheless, we have distinguished two subunitsin the whole dolomite body of the island (unit A and unit B;see legend in Fig. 2) on the basis of bedding thickness andstyle, and the presence of nodular chert. However, the strati-graphic relationship between these two subunits is uncertainas they are separated by the oblique-slip fault, which cutsacross the whole length of island from WNW to ESE.

The Lanterna unit A makes up the southwestern, mostelevated part of the island, and both the northeastern andsoutheastern points of the Jonkova Njiva promontory. Thisunit would correspond to the basal dolomite described by

BOIEVI et al. (1965). In the southern cliffs below thelighthouse between Picokare and Biljovka, beds dip steeply(subvertically) to the southwest (Fig. 2). Elsewhere in thenorthern sector of the island, bedding is not clear due tostrong tectonization and the presence of massive bodies ofcoarse dolomite breccia. Its most distinguishing feature ismedium- to thick-bedded cryptocrystalline dolomite contain-ing nodules and lenses of gray chert aligned along bedding(Fig. 8). Thin-bedded dolomites interbedded with softer siltydolomite occure in the lowermost part of the unit (Fig. 9).

Gray to beige, medium to thin-bedded dolomite devoid ofchert nodules is the distinguishing feature of the Lanterna unit

B, which makes up most of the central-northern part of the is-land (Fig. 2). The unit B is often strongly tectonized, and con-tains massive bodies of coarse dolomite breccia (Fig. 6B).

Table 1: 34S isotope data from samples of Palagrua alo unit gypsum(location 1 on Fig. 2; Fig. 3)

Sample ID d34S VCDT Elemental Composition

GYP-A 11.4 16.1

GYP-C 11.5 12.7

GYP-D 11.1 12.0


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3.2.1. Palynology of Lanterna unit A

We analyzed a soft interbed of yellowish silty dolomite ofthe Lanterna unit A exposed at the first switchback on thetrail to the lighthouse (Sample Pal12D; location 5 on Fig.2; Fig. 9), and in the coastal outcrop SW of Stara Vlaka(Sample Pal16; location 4 on Fig. 2). Sample Pal12D ispalynologically barren whereas Sample Pal16 revealed apoorly preserved, undiversified sporomorph assemblage con-taining cf.Patinasporites densus, which first appears closeto the base of the Carnian, i.e. at the base of the ammonoidaonzone palynologically characterized as thevigens den-susphase by VAN DER EEM (1983), and at the base of the

ammonoid canadensiszone designated as Assemblage B byBROGLIO LORIGA et al. (1999), respectively. Occurrencesof weakly preserved cf. Camerosporites secatusmay sugg-est that sample Pal16 is likely to be Carnian in age since itslast appearance is placed at the top of Carnian (VISSCHER& BRUGMAN, 1981; WARRINGTON, 2002).

Sample Pal16 contains a small amount of organic mat-ter, insufficient for palynofacies analysis or palaeoclimato-logical/palaeoenvironmental interpretation.

3.2.2. Age and paleoenvironmentof the Lanterna unit A

The age of the Lanterna unit A is poorly defined as LateTriassic, according to palynological results (see section 3.2.1.).

Radiolarians reported by KOROLIJA et al. (1977) fromthe chert nodules of Lanterna unit A, and traces ofLithotham-nionreported by BOIEVI et al. (1965), would indicatean age not older than Middle Jurassic for this formation. Un-fortunately, neither microfossils nor macrofossils could be de-termined in the numerous samples of dolomite inspected inthe field, or studied in thin sections. It is likely that dolomiti-zation of the parent limestone, which led to a cryptocrystallinetextural homogenization of these rocks, would have obliter-ated any original internal structure or microfossil trace.

The study of thin sections from the Lanterna unit chertnodules (Picokare and Stara Vlaka, Fig. 8) did not reveal any

radiolaria or any other kind of microfossil, nor lithic grains,which could have aided age assessment and determinationof a palaeoenvironment setting for these rocks. However, thepoorly preserved palynoflora of Pal16 including Patinas-porites,Enzonalasporites, Camerosporitesand bisaccate pol-len, suggests a semi-arid climate since these taxa representconiferalean, xerophytic plant communities.

It should be noted that chert is common in the Late Trias-sic transitional and basinal limestone and dolomite successi-ons of the southwestern Apennines (i.e. the Lagonegro-Molisebasin; BERTINELLI et al., 2005; SERVIZIO GEOLOGICODITALIA, 2007). These carbonate rocks also include brec-

cia, shale, marl and siltstone units, but dolomitization seemsto be restricted to the upper Triassic Calcari con Selce For-mation, which represents proximal to transitional deposi-tional environments. Dolomitization is not present in the Cal-cari con Selce in distal, deep-water successions. Thus, basedon palynostratigraphy (section 3.2.1.) and the analogy withthe central and southern Apenninic formations, we presumethat the lower part of the Lanterna unit may represent prox-imal or transitional carbonate platform-to-basin deposits ofLate Triassic age.

3.3. Salamandrija unit

The central part of Velika Palagrua (Salamandrija) is char-acterized by a regular, flat area, which dips toward the NNE,and is mostly covered by humic soil. A small quarry pit lo-cated some 50 m NE of the archaeological site of Salaman-drija (KIRIGIN & AE, 1998; FORENBAHER & KAI-SER, 2005; Fig. 2) reveals that this point of the island iscomposed of thick layers of light-grey to yellowish, porousbio-intra-lithoclastic to skeletal packstones and grainstones(biocalcarenites). Another outcrop occurs on the trail to thelighthouse, along the WNWESE striking fault (Fig. 2), se-parating the unit from the underlying rocks. Therefore, it isnot possible to determine the exact stratigraphic relationship

of this unit with the underlying rock units without new de-tailed field investigations. Nevertheless, the bedding attitudeof the Salamandija unit exposed in the quarry pit is appro-

Figure 8:Chert nodules and layers of gray chert aligned along bedding ofthe Lanterna unit A dolomite (Stara Vlaka cove).

Figure 9:Outcrop of Upper Triassic thin-bedded dolomite interbedded withsofter silty dolomite Lanterna unit A (location 5 on Fig. 2). Scale bar in cm.


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ximately perpendicular in respect to the Lanterna unit Bexposed along the crest of the island, suggesting a sharpangular unconformity.

3.3.1. Biostratigraphy and depositional environmentof the Salamandrija unit

Study of thin sections of the Salamandrija biocalcarenite(samples Pal10 and Pal13, location 6 on Fig. 2) confirmedthe presence of some microfossils reported by BOIEVIet al. (1965). Within recrystallized bioclastic-skeletal-litho-clastic grainstones (Fig. 10) biogenic debris mostly made upof bioclasts of sea urchins, red algae, mollusc shells and testsof benthic foraminifera was discovered. Among the latter,the most abundant areElphidiumsp.(includingElphidiumcrispum), followed byAsterigerinatasp., Melonissp.,Het-erolepasp., Gyroidinoidessp.,Ammoniasp.,Neoeponidessp., etc).E. crispumoccurs, in the Mediterranean region, inMiocene sediments (AGIP, 1982).

In a preliminary study of the fossil content of the Sala-mandrija unit, BOIEVI et al. (1965) reported, besidescasts and fragments of molluscs, fragments of calcareous al-gae, and recrystallized globigerinids, a number of benthic fo-raminifera includingRobulus sp., Amphistegina sp., Noniongranosum, N. soldanii, Rotalia beccarii,Elphidium cripumand ostracod species Cythereis tricostata. According to BOI-EVI et al. (1965), this fossil assemblage indicates a generalNeogene age, similar to a marine Pliocene assemblage foundin southern Apulia. However, the abundance ofElphidiumsp.is suggestive of a Miocene age, and, in any case, as a detritallimestone made up of reworked bio- and lithoclasts, the fossil

assemblage of the Salamandrija unit is not conducive to pre-cise age determination.

The foraminiferal association indicates an inner shelfenvironment (cf. BOLTOVSKOY & WRIGHT, 1976). BOI-EVI et al. (1965) suggest a coastal sedimentary environ-

ment based on the abundance ofAmphistegina sp. Undefinedsubangular lithoclasts of older rocks are also present, includ-ing micritic limestones containing calpionellids (tintinnids).These redeposited subangular lithoclasts suggest that olderrocks (including Mesozoic deeper-water micritic limestones)were deformed and exposed during sedimentation of the Sal-

amandrija unit.

3.3.2. Strontium isotopes of the Salamandrija unit

As an independent method to determinate age for the Sala-mandrija unit, the 87Sr/86Sr composition of a bulk biocal-carenite sample from the Salamandrija quarry pit were ana-lysed. (location 6 on Fig. 2), along with the shells of twomodern intertidal gastropods,Natica millepunctataandPa-tella coerulea, collected at the island of Hvar and representingthe present strontium isotopic composition of Adriatic seawa-ter. In addition, a sample of pelagosite, which represents a bio-aragonite related to the cyanobacterial activity in the supra-

tidal zone (see section 4.3.), and a sample of dolomite fromthe Lanterna unit A were also analysed. Analysis was under-taken at the Berkeley Institute for Isotope Geochemistry, us-ing sample preparation and an analytical procedure similar tothat described by DePAOLO & INGRAM (1985).

The results are shown in Table 2, and plotted in Fig. 11against the curve of seawater strontium composition fromthe Permian to Recent (McARTHUR et al., 2001). The com-position of the Lanterna unit A dolomite resulted in an am-biguous age determination, because of strong diagenetic al-teration of the parent rock. The 87Sr/86Sr value of 0.709072from the Salamandrija biocalcarenites provides a minimum

age of about 9 Ma (i.e. lower Tortonian).

3.3.3. Age of the Salamandrija unit

Salamandrija biocalcarenites contain a wealth of microfo-ssils and skeletal fragments of shallow-marine benthic fora-

Figure 10:Microfacies and microfossils in theMiocene biocalcarenite of the Salamandrijaunit (sample Pal13, location 6 on Fig. 2). Scalebar 0.5 mm.


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minifera, which indicate a broadly Neogene age (section3.3.1., Fig. 10). Combining the biostratigraphic data with thechemostratigraphy (section 3.3.2.; Fig. 11) a broadly Mio-cene age is proposed here for the Salamandrija unit.

3.4. Talus units and rock falls

The stratigraphic succession making up the bedrock of Ve-lika Palagrua is covered, particularly in the central part ofthe island, by loose or locally cemented talus, including brec-cia, rock-fall boulders, and soil. In the area of Stara Vlaka,a wedge of dip-slope, coarse, poorly cemented detritus cov-ers up the dolomites of the Lanterna unit B. A cross sectionof the wedge and the underlying bedrock is exposed in theStara Vlaka cove (Fig. 6A), offering the opportunity to de-termine the relationship between the cover and the underly-ing bedrock. Here, the dolomitic breccias of the Lanternaunit B are strongly tectonized, and displaced by the WNWESE striking oblique-slip fault, which puts them in contact

with the equally tectonized alo unit (Fig. 6B). The fault aswell as the contact between the alo unit and the Lanternaunit A is capped by the detrital wedge, which clearly dips

downslope toward the NE. The wedge is composed of lay-ers of poorly cemented dolomite breccia resting on top offiner, reddish debris, probably representing a lateritic soil.

Near the contact with the underlying dolomite bedrock,at 13 m asl, a deposit of rounded pebbles suspended in a red-dish sandy matrix (Fig. 12A) occurs. In between the pebbles,rare fragments of bivalve shells and pebbles showing thetypical superficial texture produced by perforating algae sug-

gest a palaeobeach depositional environment. One pebblewe collected is perforated by a lithodomus burrow, whichstill contains the original bivalve shell (Fig. 12B).

Figure 11:Plot of the 87Sr/86Sr composition of samples from the Lanternaunit A (dolomite), the Salamandrija unit (biocalcarenite), pelagosite (bio-aragonite), and modern Adriatic gastropod shells compared to the Permi-an to Present seawater 87Sr/86Sr curve of McARTHUR et al., 2001.

TABLE 2:Strontium isotope ratios of the Palagrua (PLG) samples: Lanterna unit A dolomite (cliff near Picokare, Fig. 2), Salamandrija unit biocalcarenite(locality 6 on Fig. 2) and Pelagosite sample (cliff near Picokare, Fig. 2) compared with modern mollusc shells from the Adriatic Sea (island of Hvar HVA)

Sample Material Formation Age 87Sr/86Sr Error

PLG/05-4 D dolomite Lanterna unit A Late Triassic (?) 0.707490 0.000008

PLG/05-10 L limestone Salamandrija unit Late Miocene 0.709072 0.000010

PLG/05-4 P aragonite Pelagosite Holocene 0.709232 0.000010

HVA/07 NAT calcite Natica shell Present 0.709221 0.000009

HVA/07 PAT calcite Patella shell Present 0.709235 0.000008

Figure 12:A) Outcrop of the pebbly palaeobeach of Stara Vlaka: B) arounded pebble showing the surface perforated by burrowing algae andLithodomus.

A

B


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It is uncertain whether this deposit represents the rem-nant of a Quaternary palaeobeach or an older deposit formedduring a Miocene transgression or Pliocene(?) to Quaternarymarine regressions (i.e., during the emergence of the island).As for the bedded talus, it appears that it formed in recenttimes after the emersion of the island, and it does not repre-

sent a sedimentary continuation of the Salamandrija unit.A similar talus exposure, which suggests a post-Miocene,

post-deformational talus deposit, is observed on the west sideof the Picokare ravine (see Fig. 4A). Here the poorly cement-ed breccia layers dip south, thus representing a talus slopewith a bedding direction essentially perpendicular to the Sal-amandrija unit and the Stara Vlaka talus wedge. It is worthmentioning that just below the saddle between Salamandrijaand the lighthouse peak, at about 50 m asl at the head of thePicokare ravine, we found some sparse rounded pebbles,which may represent yet another, older paleobeach deposit.

The slope on the south side of Salamandija, between

alo and Picokare, is littered by loose rock waste and boul-ders, some of which are so large that they may in fact repre-sent bedrock remnants of a strongly eroded cliff topography.It is also to be noted that, it has been reported that cata-strophic rock falls occurred in very recent times (FOREN-BAHER & KAISER, 2005).

4. NEOTECTONICS AND RELATED FEATURES

The island of Velika Palagrua can be described as a verticaltopographic feature, in which the bedrock has been emergingfrom the sea in response to active tectonics, and is affected by

marine erosion. In Section 2 we reviewed the present seismo-tectonic situation of the central Adriatic, which places Pala-grua near the emergence of a large, seismically active thrustfault (BENNETT et al. 2008), and/or in an area where wrenchtectonics and salt diapirism causes uplifting (e.g. GRANDIet al., 2002; GELETTI et al., 2008). While surveying the islandin recent years, several features were discovered, which testifyto the recent uplifting of the island. These are flat areas (marinestraths), palaeobeach deposits, and pelagosite, all occurring atdifferent elevations throughout the island.

4.1. Marine straths

There are only few places where the topography is flat atPalagrua, which contrasts with the otherwise vertical to-pography of the island. These areas may represent marinestraths (see Fig. 2 for locations). Of course, in this tiny islandthere are no extensive flat surfaces that may strictly be de-fined as a marine strath or peneplain. Thus, we use here theterm of marine strath in a general sense, indicating a flat andnearly horizontal erosional surface cutting across steeplydipping bedrock layers.

One such marine strath is found at about 75 m asl, justabove the Biljovka cove (Figs. 6A and 13A). Another pos-sible case of marine strath is represented by Salamandrija,

which is the largest flat area of the island at about 60 m asl,and, in fact, this has been the site of human settlements sincethe Early Neolithic (FORENBAHER & KAISER, 2005).

Similarly, the archaeological site of Jonkova Njiva (about 50m asl) on the eastern end of the island, and a small flat areaat about the same elevation on the westernmost point of theisland may also be considered remnants of flat erosional sur-faces. Finally, the rocky promontory composed of dolomitebreccia of the Lanterna unit B, which delimits the northernside of Stara Vlaka cove, is also cut by a flat and nearly hor-izontal surface, at about 13 m asl (Fig. 13B). This plateau isnow covered in part by large rock-fall boulders, but in itsinland part is overlain by the palaeobeach deposit.

4.2. Palaeobeach deposits

One palaeobeach deposit made up of rounded pebbles is de-scribed in Section 3.4. (Fig. 12A). A relatively conspicuousbeach deposit is found at the western foot of the Picokareravine resting at about 6 m asl, and consisting of roundedpebbles, cobbles, and boulders (up to 40 cm in diameter) freeof any matrix (Fig. 14). Some pebbles exhibit a perforatedsurface possibly caused by burrowing algae or lithophagousbivalves, but no shells, nor encrusting algal remains havebeen found so far. A deposit of rounded pebbles was observedfilling a ledge on the vertical sea cliff just above the palaeo-

beach deposit of Picokare, at about 13 m asl (Fig. 14).Although the boulders could be deposited 6 m asl fromthe recent shoreline by gigantic waves under specific hydro-

Figure 13:Marine straths A) at 75 m above sea level above the Biljovkacove, and B) making up the northern spur of Stara Vlaka cove.

A

B


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dynamic regimes, the deposit was still interpreted as a remnantof a palaeobeach, since in the footwall of the cliff pebbly beachdeposits have not been observed. Thus, the palaeobeach alsoindicates recent uplifting of the island.

Unfortunately there are no means to determine an age forthese palaeobeach deposits due to the absence of fossil re-mains. A more thorough survey of the cliffs around the light-house peak may reveal other deposits of this kind at differentelevations, and chances are that fossil remains of sea molluscscan be found, providing material for radioisotopic dating.

4.3. Pelagosite

Further evidence for the recent tectonic uplifting of Palagruacomes from black mineral incrustations with a vitreous lu-stre resembling tar, which covers, in irregular patches, therocky coast of the island from just above the tide line up to13 m asl (Fig. 15A). This strange substance was first reportedby MARCHESETTI (1876), and, one year later, it was namedpelagosite (from Pelagosa, the Latin name of Palagrua)by STOSSICH (1877).

The reports by Marchesetti and Stossich were followedby 50 years of debate in the international scientific community

about the nature and origin of this strange mineral (e.g. CLOZ,1878; SQUINABOL & ONGARO, 1901; CLERICI, 1920).Finally, ONORATO (1926) published a comprehensive paperon the morphological, mineralogical, physical, chemical, andmicrobiological characteristics of pelagosite samples from theTremiti islands, which are located some 75 km southwest ofPalagrua. Pelagosite turned out to be pisolitic aragonite. Itconsists of pearl or mamellon-shaped objects with a concen-tric ring internal structure similar to tree rings, made of apure aragonite, and solidly attached to the rocky substratum.According to ONORATO (1926), pelagosite is produced byblue-green algae (i.e., cyanobacteria) where the supralitto-

ral rock is frequently wetted by sea aerosol.Optical microscopy by MONTANARI et al. (2007) con-firmed the pisolitic structure of pelagosite, as originally ob-

served by ONORATO (1926), and showed that 23 m thickalternating dark-light laminae are arranged rhythmicallythrough mm-thick sections of pelagosite crusts (Fig. 15B).Thicker laminae contain submicron-size inclusions of or-ganic matter (Fig. 15C), including fragments of cyanobacte-rial cells (Fig. 15D) similar to those observed by ONORATO

(1926) in the Tremiti pelagosite. By assuming that these lam-inae represent yearly accretions (just like the rings in a treetrunk), MONTANARI et al. (2007) determined that their ar-rangement bears cyclicity with frequencies comparable tothose of the periodic climate changes controlled by El Nioand the North Atlantic Oscillation (i.e., dry-wet/cold-warmmeteorologic conditions alternating approximately every 3,8, and 12 years).

In a recent microbiological study of pelagosite samplesfrom Palagrua, MACALADY et al. (2008) confirmed Ono-ratos conclusion of a biogenic origin for this aragonite and,through DNA analysis of the organic fraction, they deter-

mined the presence of cells belonging toXenococcus (Fig.15D), a rare genus of cyanobacteria, and apparently a newspecies never described before.

The fact that pelagosite apparently forms within a cou-ple of metres above tide line, but today is found up to 13 mabove sea level, suggests that Palagrua is currently uplift-ing. The uplifting rate of the Gargano promontory (Apuliadomain, Fig. 1), estimated by MASTRONUZZI & SANS(2002) from U/Th dating of bioherms and other paleo-sealevel indicators, is 1.5 mm yr1. In contrast, the coastal areasof NE Adriatic (Croatia) are presently under a regime of sub-sidence (BENAC et al., 2004; ANTONIOLI et al., 2007).

The preliminary U/Th dating of pelagosite from VelikaPalagrua by MONTANARI et al. (2007), yielded ages around2200 years for samples collected between 3 and 4 m abovesea level at Picokare, and 6500 years for a sample from 6 mabove sea level, suggesting that Palagrua is uplifting at arate comparable with the uplifting rate of the Gargano prom-ontory estimated by MASTRONUZZI & SANS (2002).This encourage further work to better evaluate the potentialof this biomineral for assessing vertical tectonic movementsof littoral environments.

5. SUMMARY AND CONCLUSIONS

The tiny islands of the Palagrua archipelago represent the onlypieces of dry land exposed in the middle of the central AdriaticSea. The outcrops offer the unique opportunity to study Meso-zoic and Cenozoic deposits in the central part (Mid-Adriaticridge) of the common Adriatic foreland of the Apenninic andDinaridic orogenic domains. Our geological reconnaissance ofthe island of Velika Palagrua, the largest in the archipelago,allows us to assess some stratigraphic and tectonostructuralcharacteristics, which were never described in the few geologi-cal reports available in accessible literature.

Velika Palagrua is composed of four main sedimentary

units. However, evidence that these units are in stratigraphiccontinuity is lacking, as they are all bounded by faults anddiscordances.

Figure 14:Subvertical bedding of the dolomites of the Lanterna unit Aexposed along the littoral cliff of Picokare. Pebbly palaeobeach deposits atthe bottom of the Picokare ravine (at about 6 m asl) and in a ledge of thecliff at about 13 m asl.


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The oldest unit recognized is formed of highly deformedsiliciclastic (silt and clay) deposits containing gypsum andthin layers of stromatolitic limestones capped by a packageof thin-bedded dolomite layers. Palynomorphs contained inthe clay at the base of this succession indicate a Middle Tri-assic age (Ladinian). This unit, named alo, represents a tran-sitional fluvial-to-shallow marine, occasionally evaporiticenvironment, typical of the Middle Triassic rifting phase ofthe Adriatic microplate.

The alo unit is in discordant relationship with the young-er Lanterna unit of thick to medium-thick bedded dolomite

and dolomite breccia, with or without chert. Palynomorphsin a sample from the Lanterna unit indicate a Late Triassicage. The Lanterna unit is actually made up of two subunitsrecognizable for their different bedding thickness and style.Unit A is characterized by thick and medium-thick layers ofdolomite with chert, and unit B is characterized by massivedolomite breccia and thin- to medium-thick dolomite layersdevoid of chert. These two subunits are separated by a WNWESE striking, subvertical, oblique-slip fault, which crossesthe entire length of the island. The presence of well-beddeddolomite with chert and massive bodies of dolomite brecciasuggests a transitional platform-to-basin depositional setting

of an evolving Adriatic Basin domain.The Lanterna unit dolomites are capped by biocalcareni-

tes of the Salamandrija unit, containing abundant microfos-

sils, which, along with strontium isotope data, indicate abroadly Miocene age. The biocalcarenites bedding alignmentis highly discordant in respect to the underlying Lanternaunit, although the actual contact between the two units is notvisible because it is covered by talus. Talus, landslide depo-sits, and humic soil make up the cover of the bedrock sedi-mentary succession of the island, and they represent the ul-timate phase of emergence of the island, which probablyoccurred during Pliocene? to Quaternary times.

The bedrock units of Velika Palagrua, each one displacedby faults and/or in diapiric contact to each other, and therefore

not in stratigraphic continuity, represent just a few pieces of alarge and complicated puzzle depicting the tectono-sedimen-tary evolution of the central Adriatic basin. The almost per-pendicular discordance (unconformity?) separating the Sala-mandrija unit from the underlying Triassic dolomites suggestsa deformational phase preceding Miocene marine deposition,perhaps a marine transgression over an already deformed anderoded dolomite massif. The WNWESE striking subverticaloblique-slip fault that crosses the entire length of the island isprobably still active. Soft and strongly deformed Ladinian sil-iciclastic-evaporitic alo unit deposits occur along the fault,and may be related to diapirism.

The central Adriatic area is under an active seismic re-gime. Recent uplifting of Velika Palagrua is shown by rem-nants of pebbly palaeobeach deposits, marine (erosional)

Figure 15:A) Pelagosite encrustations on the cliff near Picokare at about 4 m above sea level; B) polished section of a pelagosite crust; C) thin sectionmicrophotograph (transmitted plain light) of a pelagosite crust from Picokare showing a rhythmic microlaminar arrangement; D) a cell of cyanobacte-riumXenococcusextracted from pelagosite.

A

C

B

D


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straths, and cyanobacterial supratidal encrustations (pela-gosite) today found at various elevations above mean sealevel. Further detailed research on the structural geology,stratigraphy, micropalaeontology, and radioisotope geo-chronology will hopefully add detailed constraints in a moreaccurate reconstruction of the geologic and tectonic history

of the Palagrua archipelago.

ACKNOWLEDGEMENT

We would like to thank Dr. Branko KIRIGIN, and his team of archae-ologist researchers, for introducing us to Palagrua and its marvels, andfor supporting us with the logistics while surveying the island in sev-eral expeditions between 2005 and 2007. We thank Ross MITCHELL,Maxwell MONTANARI, Elisabetta FERRONI, and Markus FIEBIGfor assistance during fieldwork in several separate expeditions. We arealso grateful to Matteo DAMATO and Mislav for havinggiven us aride with their fast boats to the island in the expedition of October 2005.We like to thank Simone GALEOTTI and Vincenzo PICOTTI for apreliminary microfossil identification of the Salamandrija biocalcaren-

ite. The sulphur analyses were undertaken at the University of LeedsS Isotope Facility thanks to the help of Rob NEWTON. Careful reviewsby Igor VLAHOVI, Simonetta CIRILLI, and Mladen JURAI,which significantly improved the quality of the paper, are greatly ac-knowledged. This study was partly supported by the project Stratig-raphy and Geodynamic Context of Cretaceous Deposits in the NE Adri-atic Region no. 181-1191152-2697 of the Ministry of Science,Education and Sports of the Republic of Croatia.

REFERENCES

ADLOFF, M.C., APPIA, C., DOUBINGER, J. & LIENHARDT, M.J.(1984): Zonation palynostratigraphiques dans les sries triasiquetraverses par de sondage le Jura et le Bas-Dauphin. Gol. Fr., 1,321.

ADLOFF, M.C., DOUBINGER, J., MASSA, D. & VACHARD, D.(1986): Trias de Tripolitaine (Lybie). Nouvelles donnes biostrati-graphiques et palynologiques. Deuxime partie. Rev. Inst. Fr. Pe.,41, 2772.

AGIP (1982): Foraminiferi Padani (Terziario e Quaternario). Atlanteiconografico e distribuzioni stratigrafica. 2ndedition, 52 pls.

ANTONIOLI, F., ANZIDEI, M., LAMBECK, K., AURIEMMA, R.,GADDI, D., FURLANI, S., ORR, P., SOLINAS, E., GASPARI,A., KARINJA, S., KOVAI, V. & SURACE, L. (2007): Sea-levelchange during the Holocene in Sardinia and in the northeasternAdriatic (central Mediterranean Sea) from archaeological and geo-morphological data. Quarter. Sci. Rev., 26, 24632486. doi: 10.1016/j.quascirev.2007.06.022

BATTEN, D.J. (2002): Palynofacies and palaeoenvironmental interpre-tation. In: JANSONIUS, J. & MCGREGOR, D.C. (eds.), 2ndedi-tion, Palynology: Principles and Applications. AASP Foundation,3, 10111064.

BATTAGLIA, M., MURRAY, M.H., SERPELLONI, E. & BRG-MANN, R. (2004): The Adriatic region: An independent microplatewithin the Africa-Eurasia collision zone. Geophy. Res. Lett., 31,L09605. doi:10.1029/2004gl019723.

BELAK, M., KOCH, G., GRGASOVI, T., VLAHOVI, I., VELI,I., SOKA, B. & BENEK, . (2005): Novi prinosi stratigrafijievaporitno-karbonatno-klasatino-vulkanogenog kompleksaKomikog zaljeva (otok Vis, Hrvatska) [New Contribution to theStratigraphy of Evaporitic-Carbonate-Clastic-Volcanogenic Com-plex of Komia Bay (Island of Vis, Croatia) in Croatian]. In:VELI, I., VLAHOVI, I. & BIONDI, R. (eds.): 3. Hrvatski

geoloki kongres, (3rdCroatian Geological Congress), Opatija29.09.01.10. 2005., Knjiga saetaka (Abstract Book), Hrvatskigeoloki institut Croatian Geological Survey, Zagreb, 1314.

BENAC, ., JURAI, M. & BAKRAN-PETRICIOLI, T. (2004): Sub-merged tidal notches in the Rijeka Bay NE Adriatic Sea: indicatorsof relative sea-level change and of recent tectonic movements.Mar. Geol., 212, 2133. doi: 10.1016/j.margeo.2004.09.002

BENNETT, R.A., HREINSDTTIR, S., BUBLE, G., BAI, T.,BAI, ., MARJANOVI, M., CASALE, G., GENDASZEK, A.& COWAN, D. (2008): Eocene to present subduction of southern

Adria mantle lithosphere beneath the Dinarides. Geology, 36/1,36. doi: 10.1130/G24136A.1

BERTINELLI, A., CIARAPICA, G. & PASSERI, L. (2005): Late Trias-sicJurassic basinal successions in Molise and northern Basili-cata: the northernmost witness of the Ionian Ocean. Boll. Soc.Geol. It., 124, 177188.

BERTOTTI, G, PICOTTI, V., CHILOVI, C., FANTONI, R., MERLINI,S. & MOSCONI, A. (2001): Neogene to Quaternary sedimentarybasins in the south Adriatic (Central Mediterranean): Foredeeps andlithospheric buckling. Tectonics, 20/5, 771787.

BESEMS, R.E. (1983): Aspects of Middle and Late Triassic palynol-ogy. 3. Palynology of the Hornos-Siles Formation (Prebetic Zone,Province of Jan, Southern Spain) with additional information on

the macro- and microfaunas. sterreich. Akad. Wissensch.Schriftenr. Erdwissensch. Komm., 5, 3756.

BEUTLER, G., HEUNISCH, C., LUTTPOLD, F.W., RETTIG, B. &RHLING, H.-G. (1996): Muschelkalk, Keuper und Lias am Mit-tellandkanal bei Sende (Niedersachsen) und die regionale Stellungdes Keupers. Geol. Jb., A 145, 67197.

BLENDINGER, E. (1988): Palynostratigraphy of the Late Ladinian andCarnian in the Southern Dolomites. Rev. Palaeobot. Palynol., 53,329348. doi: 10.1016/0034-6667(88)90038-3

BOGNAR, A. (1995): Geomorphological characteristics of the Pala-grua Archipelago: in Palagrua the Pearl of the Adriatic. Pro-ceeding of the Croatian Meterological Society, Split, 8795.

BOLTOVSKOY, E. & WRIGHT, R. (1976): Recent Foraminifera. TheHague, Dr. W. Junk b.v. Publishers, 515 p.

BOSELLINI, A. (2002): Dinosaurs re-write the geodynamics of theeastern Mediterranean and paleogeography of the Apulia Platform.Earth-Sci. Rev., 59/(14), 211234. doi: 10.1016/S0012-8252(02)00075-2

BOIEVI, S., MULDINI-MAMUI, S. & VRSALOVI-CAREVI,I. (1965): The sedimentary-petrographic and palaeontologic char-acteristics of the insular group of Palagrua. Bull. Acad. CouncilSci. RSF Yugoslavia, Section A, Zagreb, 10, 6667.

BRACK, P., RIEBER, H., NICORA, A. & MUNDIL, R. (2005): TheGlobal boundary Stratotype Section and Point (GSSP) of the Ladin-ian Stage (Middle Triassic) at Bagolino (Southern Alps, NorthernItaly) and its implication for the Triassic time scale. Episodes, 28,233244.

BROGLIO LORIGA, C., CIRILLI, S., DE ZANCHE, V., DI BARI, D.,GIANOLLA, P., LAGHI, G.F., LOWRIE, W., MANFRIN, S., MA-STANDREA, A., MIETTO, P., MUTTONI, G., NERI, C., POSEN-ATO, R., RECHICHI, M., RETTORI, R. & ROGHI, G. (1999): ThePrati di Stuores/Stuores Wiesen Section (Dolomites, Italy): A Can-didate Global Stratotype Section and Point for the Base of the Car-nian Stage. Riv. Ital. Paleontol. Stratigr., 105, 3778.

BRUGMAN, W.A. (1986): Palynological characterization of the UpperScythian an Anisian of the Trans-Danubian Central Range (Hun-gary) and the Vicentinian Alps (Italy). Unpubl, PhD. Thesis, Uni-versity of Utrecht, 95 p.

BRUGMAN, W.A., VELD, H., VAN BUGGENUM, J.M., HOLSHU-IJSEN, R.P., BOEKELMAN, W.A., VAN DEN BERGH, J.J.,ALMEKINDERS, M.P., POORT, R.J., ABBINK, O.A. &

DENGELBRONNER, E.R. (1988): Palynological investigationwithin the Triassic of the Germanic Basin of Southern Germany.Stuifmail, 6, 5254.


17/20


91

BRUGMAN, W.A., VAN BERGEN, P.R. & KERP, J.H.F. (1994): A quan-titative approach to Triassic palynology, the Lettenkeuper of the Ger-manic Basin as an example. In: TRAVERSE, A. (ed.): Sedimenta-tion of Organic Particles. Univ. Press Cambridge, 409429.

BRHWILER, T., HOCHULI, P.A., MUNDIL, R., SCHATZ, W. &BRACK, P. (2007): Bio- and chronostratigraphy of the Middle Tri-assic Reifling Formation of the westernmost Northern Calcareous

Alps. Swiss J. Geosci., 100, 443455. doi: 10.1007/s00015-007-1240-2

CHANNELL, J.E.T., DARGENIO, B. & HORVATH, F. (1979): Adria,the African promontory, in Mesozoic Mediterranean palaeogeogra-phy. Earth-Sci. Rev., 15, 213292. doi: 10.1016/0012-8252(79)90083-7

CHIARABBA, C., JOVANE, L. & DISTEFANO, R. (2005): A new viewof Italian seismicity using 20 years of instrumental recordings.Tectonophys., 395, 251268. doi: 10.1016/j.tecto.2004.09.013

CLERICI, E. (1920): Pelagosite di Canalgrande nellInglesiente. Ren-diconti dellccademia dei Lincei, Serie 5, Fascicolo 11.

CLOZ, S. (1878): Note sur une matire minrale dapparance vitreuse,qui se depose sur la roche littoral de la Mditerrane. Bull. Soc.Gol. France, 6, 84.

COURTINAT, B. & RIO, M. (2004): The Statistical analysis of palyno-facies of the Ladinian strata of the South east Massif central, France(Analyse statistique de palynofacis des dpts ladinien du SE duMassif central franais). Rev. Micropal., 47, 2835. doi: 10.1016/j.revmic.2004.01.002

CROS, P. & DOUBIGNER, J. (1982): tude palynologiques de sdi-ments terrignes et plagique du Trias moyen des Dolomites itali-ennes. Relation avec la palonvironnement. Sci. Gol. Bull., 35,157182.

DePAOLO, D.J. & INGRAM, B.L. (1985): High-resolution stratigraphywith strontium isotopes. Science, 227, 938941. doi: 10.1126/sci-ence.227.4689.938

ESHET, Y. (1990): Paleozoic-Mesozoic Palynology of Israel. 1. Palyno-

logical Aspects of the Permo-Triassic Succession in the Subsurfaceof Israel. Geol. Surv. Isr. Bull., 81, 157.

FORENBAHER, S. & KAISER, T. (2005): Palagrua i irenje zemljo-radnje na Jadranu (Palagrua and the spread of the farming in theAdriatic). Opvscula Archaeologica, 29, 723.

GARCIA GIL, S. & DIEZ, J.B. (2006): Microflora of the MuschelkalkSedimentary Cycle in the NW Iberian Range, Central Spain. 7 thEuropean Palaeobotany-Palynology Conference, September 611,Praque, Program and Abstracts, 47.

GELETTI, R., DEL BEN, A., BUSETTI, M., RAMELLA, R. & VOLPI,V. (2008): Gas seeps linked to salt structures in the Central Adri-atic Sea. Basin Res., 20, 473487. doi: 10.1111/j.1365-2117.2008.00373.x

GCZN, F. & ORAVECZ-SCHEFFER, A. (1993): The Anisian/Ladin-ian Boundary in the Transdanubian Central Range based on paly-nomorphs and foraminifers. Acta Geol. Hung., 36, 73143.

GORIAN, ., HALAMI, J., GRGASOVI, T. & KOLAR-JURKOVEK, T. (2005): Stratigraphic evolution of Triassic arc-backarc system in northwestern Croatia. Bull. Soc. Gol. France,176, 322. doi: 10.2113/176.1.3

GRANDI, S., BOROMISA-BALA, E., UTERI, M. (1997): Ex-ploration concept and characteristics of the stratigraphic and struc-tural models of the Dinarides in Croatian offshore area. Nafta,48/89, 249266.

GRANDI, S., BIANCONE, M. & SAMARIJA, J. (2002): Geophysi-cal and Stratigraphic Evidence of the Adriatic Triassic Rift Struc-tures. Mem. Soc. Geol. It., 57, 315325.

GRGASOVI, T. & SOKA, B. (2003): Review on fossil dasycla-dalean associations in the Triassic of Croatia. Acta Micropalae-ont. Sinica, 20/1, 7579.

HERAK, M., HERAK, D. & MARKUI, S. (1996): Revision of theearthquake catalogue and seismicity in Croatia (19081992). Ter-ra Nova, 8, 8696. doi: 10.1111/j.1365-3121.1996.tb00728.x

HEUNISCH, C. (1986): Palynologie des unteren Keupers in Franken sdDeutschlands. Palaeontographica B, 200, 33110.

HEUNISCH, C. (1999): Die Bedeutung der Palynologie fr Biostrati-graphie und Fazies in der Germanischen Trias. In: HAUSCHKE,

N. & WILDE, V. (eds.): Trias. Eine ganz andere Welt. Mitteleu-ropa im frhen Erdmittelalter. Verlag Dr. Friedrich Pfeil, Mnch-en, 207220.

HOCHULI, P.A. & ROGHI, G. (2002): A palynological view on theAnisian/Ladinian boundary new results from the Seceda section(Dolomites, Northern Italy). I.U.G.S. Commission on TriassicStratigraphy, STS/IGCP 467, Field Meeting, Veszprm, Hungary,58 September 2002, Geological Institute of Hungary, Program andAbstracts, 2930.

KIRIGIN, B. & AE, S. (1998): Archaeological evidence for the cultof Diomedes in the Adriatic. Hesperia, 9, 63110.

KOROLIJA, B., BOROVI, I., GRIMANI, I., MARINI, S.,JAGAI, T., MAGA, N. & MILANOVI, M. (1977): Osnovnageoloka karta SFRJ 1:100 000. Tuma za Lastovo, Korulu iPalagruu, K 3346, K 3347 i K 3357. [Basic Geological Mapof SFRY 1:100 000, Geology of the Lastovo, Korula and Palagrua

sheets in Croatian]. Institut za geoloka istraivanja, Zagreb,Savezni geolki zavod, Beograd, 53 p.

KOVCS, S., DOSZTLY, L., GCZN, F., ORAVECZ-SCHEFFER,A. & BUDAI, T. (1994): The Anisian-Ladinian boundary in theBalaton Highland, Hungary a complex microbiostratigraphic ap-proach. Albertiana, 14, 5364.

LUI, D., KOCH, G., FOREK, G., MARETI, S., BALA-BOROMISA, E., KRIZMANI, K., PANI, D., MESI, I. &BUBNI, J. (2003): Lithofacies, palynofacies and organic facies ofTriassic evaporitic-carbonate succession: Examples from Croatianoff-shore and Syrian on-shore wells. 22ndIAS Meeting of Sedi-mentology, Opatija. Abstracts Book, 111.

MACALADY, J.L., MONTANARI, A., BICE, D.M., SCHAPERDOTH,I., MACLEAN, L. & MARIANI, S. (2008): Pelagosite climaterecord and the role of cyanobacterial biomineralization. Geochim.Cosmochim. Acta, 72/2, A579.

MARCHESETTI, C. (1876): Descrizione dellIsola di Pelagosa. Boll.Soc. Adriatic. Sci. Nat., 2, Trieste, 283306.

MARIANI, S., MAINIERO, M., BARCHI, M., VAN DER BORG, K.,VONHOF, H. & MONTANARI, A. (2007): Use of speleologic da-ta to evaluate Holocene uplifting and tilting: an example from theFrasassi anticline (northeastern Apennines, Italy). Earth Planet.Sci. Lett., 257, 313318. doi: 10.1016/j.epsl.2007.02.045

MASTRONUZZI, G. & SANS, P. (2002): Holocene uplift rates andhistorical rapid sea-level changes at the Gargano promontory,

Italy. J. Quarter. Sci. 17, 593606. doi:10.1002/jqs.720McARTHUR, J.M., HOWARTH, R.J. & BAILEY, T.R. (2001): Stron-

tium Isotope Stratigraphy: LOWESS Version 3: Best fit to the ma-rine Sr-Isotope Curve for 0509 Ma and accompanying look-uptable for deriving numerical age. J. Geol., 109, 155170. doi:10.1086/319243

MONTANARI, A., BICE, D., DRUSCHEL, G., MARIANI, S., MAR-SHALL, C., OLCOTT, A., SHARP, W., TIGUE, T. & VUCETI,M. (2007): Rediscovering pelagosite: a Mediterranean microstro-matolite recording recent climate cycles. Geophys. Res. Abstr.,9, 01555, 2007, SRef-ID: 16077962/gra/EGU2007-A-01555.

ONORATO, E. (1926): Sulla pelagosite delle Isole Tremiti nellAdriatico.Boll. Soc. Geolog. Ital., 45, 1731.

OROWSKA-ZWOLISKA, T. (1983): Palinostratygrafia epikonty-

nentalnych osadw wyszego triasu w Polsce (Palynostratigraphyof the upper part of Triassic epicontinental sediments in Poland).Pr. Inst. Geol., 104, 189.


18/20


REITZ, E. (1985): Palynologie der Trias in Nordhessen und Sdnieder-sachsen. Geol. Abh. Hessen, 86, 136.

RIDENTE, D. & TRINCARDI, F. (2006): Active foreland deforma-tion evidenced by shallow folds and faults affecting late Quater-nary shelf-slope deposits (Adriatic Sea, Italy). Basin. Res., 18,171188.

ROGHI, G. (2004): Palynological investigation in the Carnian of the

Cave del Predil are (Julian Alps, NE Italy). Rev. Palaeobot. Paly-nol., 132, 135. doi:10.1016/j.revpalbo.2004.03.001

SERVIZIO GEOLOGICO DITALIA (2007): Carta Geologica dItalia1:50.000 Catalogo delle Formazioni Quaderni. Serie III Vol-ume 7 Fascicolo VII Unit tradizionali (2).

SCHEURING, B. (1978): Mikrofloren aus den Meridekalken des Mon-te San Giorgio (Kanton Tessin). Schweiz. Palont. Abh., 100,1205.

SCHULZ, E. & HEUNISCH, C. (2005): Palynostratigraphische Glieder-ungsmglichkeiten des deutschen Keupers. In: BEUTLER, G.(Coord.), Stratigraphie von Deutschland IV, Keuper. Cour. Forsch.Inst. Senckenberg, 253, 4349.

SOKA, B., AVNIAR, B. & VELI, I. (1980): Klastiti donjeg tri-

jasa uz evaporite na otoku Velika Palagrua (Sredinji Jadran) [TheLower Triassic clastics and the evaporites on the island of VelikaPalagrua (Central Adriatic) in Croatian ]. Geol. vjesnik, 32,207212.

SQUINABOL, S., & ONGARO, G. (1901): Sulla pelagosite. Riv. Min-eralog. Cristallograf., 24, 44.

STACHE, G. (1876): Geologische Notizen ber die Insel Pelagosa. Ver-handungen d. Geol. Reichsanst., 6, 123127.

STOSSICH, M. (1877): Sulla geologia e zoologia dellIsola di Pelago-sa. Boll. Soc. Adriatic. Sci. Nat., 3, Trieste, 186.

STUR, D. (1874): Tertir petrefacte von der Insel Pelagosa in Dalmatien,eingesendetvon Herrn G. Buchich in Lesina. Verhandlungen d.geol. Reichsanst., 391.

IFTAR, D. (1987): Primjena izotopne analize sumpora u odreivanjustarosti anhidrita iz Jadranskog evaporitskog podruja [The useof sulfur isotope analysis in the age determination of the Adriatic

evaporitic area anhydrites in Croatian]. Geol. vjesnik, 40,6574.

TARI, V. (2002): Evolution of the northern and western Dinarides: atectonostratigraphic approach. European Geosciences Union,Stephan Mueller Special Publication Series, 1, 223236.

TYSON, R.V. (1995): Sedimentary organic matter. Organic facies andpalynofacies. Chapman and Hall, 591 p.

VAN BERGEN, P.F. & KERP, J.H.F. (1990): Palynofacies and sedimen-tary environments of a Triassic section in southern Germany. In:FERMONT, J.J. & WEEGINK, J.W. (eds.): International sympo-sium on organic petrology. Med. Rijks Geol. Dienst, 45, 2339.

VAN DEN BERGH, J.J. (1987): Aspects of Middle and Late Triassic

palynology. Palynologocal investigation in the Keuper (Upper Ladi-nian, Karnian, Norian and Rhaetian) and Lower Jurassic (Lias 1+ 2) of Franken, SE West-Germany. Stuifmail, 5, 2633.

VAN DER EEM, J.G.L.A. (1983): Aspects of Middle and Late Triassicpalynology. 6. Palynological investigation in the Ladinian and Kar-nian of the Western Dolomites, Italy. Rev. Palaeobot. Palynol., 39,189300. doi:10.1016/0034-6667(83)90016-7

VISSCHER, H. & KRYSTYN, L. (1978): Aspects of Late Triassic paly-nology. 4. A palynological assemblage from the ammonoid-con-troled Late Karnian (Tuvalian) sediments of Sicily. Rev. Palaeobot.Palynol., 26/ 14, 93113. doi:10.1016/0034-6667(78)90007-6

VISSCHER, H. & BRUGMAN, W.A. (1981): Ranges of selected paly-nomorphs in the Alpine Triassic of Europe. Rev. Palaeobot. Paly-nol. 34, 115128. doi: 10.1016/0034-6667(81)90069-5

VISSCHER, H. & VAN DER ZWAN, C.J. (1981): Palynology of theCircum-Mediterranean Triassic: Phytogeographical and Palaeocli-matological Implications. Geol. Rundsch., 70, 625634. doi: 10.1007/BF01822140

VISSCHER, H., VAN HOUTE, M., BRUGMAN, W.A. & POORT, R.J.(1994): Rejection of a Carnian (Late Triassic) pluvial event inEurope. Rev. Palaeobot. Palynol., 83, 217226. doi: 10.1016/0034-6667(94)90070-1

VLAHOVI, I., TILJAR, J., VELI, I., & MATIEC, D. (2005): Ev-olution of the Adriatic Carbonate Platform: Palaeogeography, mainevents and depositional dynamics. Palaeogeog., Palaeoclimatol.,Palaeoecol., 220/34, 333360. doi: 10.1016/j.palaeo.2005.01.011

WARRINGTON, G. (2002): Triassic Spores and Pollen. In: JAN-

SONIUS, J. & MCGREGOR, D.C. (eds.), 2ndedition, Palynology:Principles and Applications. AASP Foundation, 2, 755766.

YAROSHENKO, O.P. & BASH IMAM, I. (1995): Age Variability ofPalynomorph Compositions of the Middle and Late Triassic ofSyria and their Relation to Climate and Facies. Stratigr. Geo.Correl., 3, 375392.

ZAPPATERRA, E. (1994): Source rock distribution model of the Peri-adriatic region. AAPG Bull., 78/3, 333354.

Manuscript received December 10, 2008

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APPENDIX 1.

LIST OF AUTOCHTHONOUS LADINIANPALYNOMORPHS FROM THE ALO UNITCLAYSTONES SAMPLE PAL6, LOCATION 1ON FIG. 2

Spores

Calamospora tener (LESCHIK, 1955) MDLER, 1964a 0.6%Calamospora keuperianaMDLER, 1964a 0.6%Todisporites minor COUPER, 1958 0.2%Todisporites major COUPER, 1958 0.2%Todisporites cinctus(MALJAWKINA, 1964) OROWSKA-

ZWOLISKA, 1971 0.4%Deltoidospora minor (COUPER, 1953) POCOCK, 1970 0.2%Concavisporites toralis(LESCHIK, 1955) NILSSON, 1958 0.8%Concavisporites crassexiniusNILSSON, 1958 0.4%Osmundacidites wellmanii COUPER, 1953 0.2%

Verrucosisporites morulaeKLAUS, 1960 0.2%Uvaesporites gadensis PRAEHAUSER-ENZENBERG, 1970 1.2%Porcellispora longdonensis(CLARKE, 1965) SCHEURING, 1970 0.4%Anapiculatisporites spiniger(LESCHIK, 1955) REINHARDT, 1961

1.4%Sellaspora rugoverrucataVAN DER EEM, 1983 0.2%Kyrtomisporis erveiVAN DER EEM, 1983 1.4% (Fig. 7/1)Aratrisporitesfimbriatus (KLAUS, 1960) MDLER, 1964a 0.4%Leschikisporis aduncus (LESCHIK, 1955) POTONI, 1958 emend.

BHARADWAJ & SINGH, 1964 0.4%

Pollen

Enzonalasporites sp.Patinasporites sp.Heliosaccus dimorphus MDLER, 1964b 0.4% (Fig. 7/4)Cannanoropollis scheuringiiBRUGMAN, 1986 1.4% (Fig. 7/3)Kuglerina meieriSCHEURING, 1978 0.8%Doubingerispora filamentosaSCHEURING, 1978 0.2% (Fig. 7/2)Infernopollenites sulcatus(PAUTSCH, 1958), SCHEURING, 1970

0.4%

Lunatisporites acutusLESCHIK, 1955 emend. SCHEURING, 1970 4.2%(Fig. 7/5)

Striatoabieites aytugiiVISSCHER, 1966 emend. SCHEURING,1970 0.8% (Fig. 7/6)

Striatoabieites balmei KLAUS, 1964 emend. SCHEURING, 1978 4.6%

Triadispora plicata KLAUS, 1964 0.4% (Fig. 7/7)Triadispora crassa KLAUS, 1964 0.4%Triadispora stabilis SCHEURING, 1970 emend. SCHEURING, 1978

0.4%

Triadispora verrucata(SCHULZ, 1966) SCHEURING, 1970 1.2%Podosporites amicusSCHEURING, 1970 emend. SCHEURING, 1978

1.2%Brachysaccus neomundanusMDLER, 1964a 3.8%Samaropollenites speciosusGOUBIN, 1965 3.8%Ovalipollis pseudoalatus(THIERGART, 1949) SCHUURMAN, 1976

24.8% (Fig. 7/8)Staurosaccites quadrifidusDOLBY, 1976 in DOLBY & BALME, 1976

1.8%(Fig. 7/9)Vitreisporites pallidus(REISSINGER, 1950) NILSSON, 1958 1.2%Alisporites opiiDAUGHERTY, 1941 emend. JANSONIUS, 1971

2.4%

Falcisporites stabilisBALME, 1970 0.8%Sulcatisporites kraeuseli MDLER, 1964a 1.8%Microcachryidites fastidioides(JANSONIUS, 1962) KLAUS, 1964 7.4%Haberkornia gudati SCHEURING, 1978 0.4% (Fig. 7/10)HaberkorniaparvaSCHEURING, 1978 0.4%Praecirculina granifer(LESCHIK, 1955) KLAUS, 1960 0.6%Partitisporites verrucosa(PRAEHAUSER-ENZENBERG, 1970) VAN

DER EEM, 1983 0.8%Duplicisporites granulatusLESCHIK, 1955 0.4%Duplicisporites verrucosusLESCHIK, 1955 0.4%(Fig. 7/11)Camerosporites secatusLESCHIK, 1955 emend. SCHEURING, 1978

15.8% (Fig. 7/12)Ephedripites primusKLAUS, 1963 0.4%Cycadopites follicularisWILSON & WEBSTER, 1946 0.8%Aulisporites astigmosus(LESCHIK, 1955) KLAUS, 1960 1.4%

(Fig. 7/13)

Prasynophycean algae

Leiosphaeridia sp. div. 3.6%

Acritarcha

Veryhachium sp. 0.4% (Fig. 7/14)Micrhystridium sp. 0.4%Dictyotidium tenuiornatumEISENACK, 1955 1.2%

Coenobial chlorophycean alga (Chlorococcales)

Plaesiodictyon mosellanumWILLE, 1970 0.2%

Botryococcus sp. 0.2%


20/20


APPENDIX 3.

LIST OF PALYNOMORPH GROUPS ACCORDINGTO THEIR BOTANICAL AFFINITY ANDECOLOGICAL SENSITIVITY

A Leschikisporis aduncusB Calamospora spp.,Todisporites spp.C Deltoidospora spp., Concavisporitesspp.D Osmundacidites spp., Verrucosisporites spp.,

Anapiculatisporites spp.E Uvaesporites spp., Sellaspora spp.F Kyrtomisporis ervei

G Aratrisporitesspp.H Cycadopitesspp.,Aulisporites astigmosus,

Ephedripites primus

I Porcellispora longdonensisJ Vitreisporites pallidus,Alisporitesspp.,K Brachysaccus neomundanus,Falcisporites stabilis, Sulcatispo-

rites kraeuseli, Microcachryidites fastidioides,Podosporitesamicus,Samaropollenites speciosus

L Ovalipollis pseudoalatus, Staurosaccites quadrifidusM Infernopollenites spp.,Lunatisporites spp.,

Striatoabieites spp.N Triadisporaspp.O Heliosaccus dimorphus,Cannanoropollis scheuringii,

Kuglerina meieri,Doubingerispora filamentosaP Haberkornia gudati,Haberkorniaparva,

Praecirculina granifer,Partitisporites spp.,Duplicisporites spp., Camerosporites secatus

Q Leiosphaeridiaspp.,R Plaesiodictyon mosellanum,Botryococcusspp.

S Veryhachiumspp.,Micrhystridiumspp.,Dictyotidium tenuiornatum

APPENDIX 2.

LIST OF REWORKED PERMIAN AND LOWERTRIASSIC PALYNOMORPHS FROM THE ALOUNIT CLAYSTONESSAMPLE PAL6, LOCATION 1 ON FIG. 2

Spores

Cyclotriletessp.Endosporites papillatus JANSONIUS, 1962 (Fig. 7/17)Densoisporites nejburgii(SCHULZ, 1964) BALME, 1970 (Fig. 7/16)Lundbladisporasp.Kraeuselisporites sp.

Pollen

cf.Nuskoisporitessp.Limitisporitessp.

cf.Lueckisporites virrkiae

Acritarcha

Micrhystridiumsp.

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Palagrudža Geologie