Citation
Microfacies of the Triassic limestones in the Piatra Åžoimuliu Klippe (Transylvanian Nappes, Rarau syncline, eastern Carpathians, Romania)

Material Information

Title:
Microfacies of the Triassic limestones in the Piatra Åžoimuliu Klippe (Transylvanian Nappes, Rarau syncline, eastern Carpathians, Romania)
Creator:
Popescu, Daniela Alexandra
Popescu, Liviu Gheorghe
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Geology ( local )
Genre:
Article
serial ( sobekcm )
Location:
Romania
Coordinates:
46 x 25

Notes

General Note:
The Piatra Åžoimului klippe belongs to the allochtonous sedimentary succession of the Transylvanian Nappes in the Raru Syncline. It is situated on the western flank of the syncline over the Callovian -- Oxfordian jaspers. The identified micropaleotologic association consists of dasycladales, foraminifera, sphynctozoa, echinoderms, etc. which indicate Pelsonian-Norian age. The microfacies of these limestones demonstrate the origin of Piatra Åžoimului klippe from a previously carbonate platform situated to the west of the Bucovinian sedimentary domain. The correlation between the allochemic and ortochemic components described in the numerous microfacies types proves that the Triassic sedimentation took place in an internal platform domain.
Restriction:
Open Access
General Note:
See Extended description for more information.

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
K26-00085 ( USFLDC DOI )
k26.85 ( USFLDC Handle )
7155 ( karstportal - original NodeID )

USFLDC Membership

Aggregations:
Karst Information Portal

Postcard Information

Format:
Serial

Downloads

This item has the following downloads:


Full Text
Description
The Piatra oimului klippe belongs to the allochtonous
sedimentary succession of the Transylvanian Nappes in the
Raru Syncline. It is situated on the western flank of the
syncline over the Callovian --
Oxfordian jaspers. The identified micropaleotologic
association consists of dasycladales, foraminifera,
sphynctozoa, echinoderms, etc. which indicate
Pelsonian-Norian age. The microfacies of these limestones
demonstrate the origin of Piatra oimului klippe from a
previously carbonate platform situated to the west of the
Bucovinian sedimentary domain. The correlation between the
allochemic and ortochemic components described in the
numerous microfacies types proves that the Triassic
sedimentation took place in an internal platform domain.



PAGE 1

STUDIA UNIVERSITATIS BABE -BOLYAI, GEOLOGIA, XLIX, 1, 2004, 87-105 MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE (TRANSYLVANIAN NAPPES, RAR U SYNCLINE, EASTERN CARPATHIANS, ROMANIA) DANIELA POPESCU 1 & LIVIU POPESCU 1 ABSTRACT. The Piatra oimului klippe belongs to the allochtonous sedimentary succession of the Transylvanian Nappes in the Rar u Syncline. It is situated on the western flank of the syncline over the Callovian Oxfordian jaspers. The identified micropaleotologic association consists of dasycladales, foraminifera, sphynctozoa, echinoderms, etc. which indi cate PelsonianNorian age. The microfacies of these limestones demonstrate the or igin of Piatra oimului klippe from a previously carbonate platform situated to the west of the Bucovinian sedimentary domain. The correlation between the allochemic and ortochemic components described in the numerous microfacies types proves that the Triassic sedimentation took place in an internal platform domain. Keywords: Microfacies, paleoecology, Triassic, Piatra oimului klippe, Transylvanian Nappes. INTRODUCTION The Transylvanian Nappes constitute t he upper part of the Central EastCarpathian Nappe System (t he Median Dacides) which is part of the Crystalline Mesozoic Area of the Eastern Carpathians. This position favored their fragmentation in the process of obduction and slow gravitational decollement. Under these circumstances it is difficult to establish the exclusively Mesozoic sedimentary series belonging to the Transylvanian Nappes, espe cially because the majority of the lithostratigraphic members appear only as is olated olistoliths in the HauterivianAptian wildflysh of the Bucovinian Nappe. The olistolith blocks appear on approximately 100 150 km from the Rar u Syncline, in the north, to the Coma na locality, in the south (the southwestern part of the Per ani Mountains). The fossiliferou s content of the olistoliths permitted to reconstruct a sedimentary series of Triassic-Early Cretaceous age, with an important gape corresponding to the CallovianOxfordian (Mutihac, 1990). The klippes dimensions vary from mete r-scale blocks to real mountain massifs, such as the limestones in the Rar u Syncline: Piatra Zimbrului, Piatra oimului, Pietrele Albe, Popii Rar ului, etc. The Piatra oimului klippe, made up only of Triassic carbonate rocks, is situated on the western flank of the Rar u Syncline. It is the only klippe from this syncline disposed on the Callovian-Oxfordian jaspers of the Bucovinian Nappe (Fig. 1). This situation generated different opinions regarding their age and tectonic position. Most of the geologists uphold their allochton position as klippe incorporated 1 tefan cel Mare University, Faculty of History and Geography, Department of Geography, 9 University Str., 720225, Suceava, Romania (danys@atlas.usv.ro).

PAGE 2

DANIELA POPESCU, LIVIU POPESCU 88 in the newest deposits of the Bucovinian Nappe (Krutner, 1929; Patrulius, 1966, 1967; Patrulius et al., 1971; Mutihac et al., 1969; Mutihac, 1966ab, 1968, 1990; Mir u & Gheorghian, 1978; Grasu et al., 1995; Turcule 2004). Other authors, such as Popescu & Patrulius (1964), Mutihac & Mir u (1964) and Turcule (1971) considered that the limestones outcropping behind the Rar u chalet, called Piatra oimului, belong to the normal succession of the Triassic in the Bucovinian unit. The arguments of the last author in favor of the in situ character of these deposits are of lithological nature. He underlined their petrographic and paleontologic similarities with limestones disposed on the massive dolomites from the northern area of the Rar u Syncline. Fig. 1 Geological sketch of the carbonate Triassic rocks from the Piatra oimului klippe (under the tourists balcony, NW slope). Bucovinian Nappe: 1-crystalline basement; 2-sandstones, Seisian; 3-dolomites, Lower Anisian; 4-jaspers, CallovianOxfordian; 5-wildflysh, Hauterivian-Albian. Transylvanian Nappes: 6-bedded limestones, Pelsonian-Illyrian; 7-massive limestones, Ladinian Norian; 8-limestone rubble. LITHOLOGIC AND STRA TIGRAPHIC ASPECTS The limestones from the Piatra oimului klippe stratigraphically cover the Middle Anisian-Norian interval. The Middle Anisian deposits consist of grey-white limestones with various yellow hues on altered surfaces. They outcr op at the bottom of the north-western slope of the Piatra oimului klippe (under the tourists balcony). The limestones are very hard and they are disposed in thin beds of 2-10 cm thickness. They are mostly covered by limestone rubble, an d outcrop on a thickness of approximately 6-7 m (Fig. 1). The limestones which represent the most part of the Piatra oimului klippe belong to the LadinianCarnian This stratigraphic assignement is sustained by the different micropaleontologic associations identified in the two extremities of the klippe. The north-western slope of the Piatra oimului klippe is characterized by lithological uniformity, being made up only of grey, hard, massive limestones, developed on approximately 50 53 m, and disposed on a thin bedded level of Pelsonian-Illyrian limestones with Oligoporella pilosa PIA (Fig. 3). The uniform macroscopic aspect of the limestones makes it impossible a lithological differentiation of Ladinian deposits from the Carnian ones. Nevertheless, the presence of the two stages is argued by paleontological assemblages reach in algae (predominantely dasyclads), segmented calcisponges (sphinctozoa) and, in certain cases, foraminifera.

PAGE 3

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 89 Fig. 2. Geological sketch of the Transylvanian carbonate Triassic from the Piatra oimului klippe (south-eastern slope). Bucovinian Nappe: 1-crystalline bas ement; 2-dolomites, Lower Anisian; 3-jaspers, Callovian-Oxfordian. Transylvanian Nappes: 4-grey thin bedded limestones; 5-white limestones; 6-red calcareous breccia; 7-stromatolitic pink limestones; 8-white massive limestones, Norian; 4-7 Ladinian-Carnian. On the south-eastern slope, behind the Rar u chalet, the Ladinian-Carnian succession starts with a carbonate bedded level of 6 7 m thickness, covered mostly by the limestone rubble (Fig. 2). It is made up of thin-bedded (0.5-7 cm) grey limestones, with different hues on fresh surfaces, and yellow on altered areas. They are followed by white, poorly silici ous limestones. The overlying deposit is a breccia (3 m) with a pink-reddish matrix and angular grey limestones elements. At its upper part it contains a white, massive, stromatolitic level, with very thin pinkreddish parallel lamellae (Fig. 4). The limestone from the south-eastern extremity of the Piatra oimului klippe is reach in cyanobacterial nodules, some algae and foraminifera. The Norian deposits consist of massive, grey-white limestones that appear at the upper part of the Piatra oimului klippe. MICROFACIES The microscopic study of the limestones of the Piatra oimului klippe allowed the differentiation of several micr ofacies types whose micropaleontological content covers the Middle AnisianNorian time interval. The Anisian microfacies (1) are: pelmicrites and biomicrosparites. They appear only at the bottom of the north-western slope of the klippe as a thin (7 m) bedded level (Fig. 3). The Ladinian-Carnian microfacies (2), according to their frequency, are: algal biopelmicrites, algal biopelsparites, pe lintramicrites, pelmicrosparites, microsparites, sparites, biosparites and biomicrites. They make up the massive limestones outcropping in both slopes.

PAGE 4

DANIELA POPESCU, LIVIU POPESCU 90 The Norian microfacies (3), (micrites and intramicrites), have been identified in the massive, grey limestones, situated at the upper part of the north-western slope, immediately under the tourists balcony. Fig. 3. Succession of the Triassic carbonate deposits from the Piatra oimului klippe, north-western slope (under the tourists balcony): 1-pelmicrites; 2-microsparites; 3-pelsparites; 4-sparites; 5-pelmicros parites; 6-intramicrites; 7-micrites. 1. Anisian Microfacies The pelmicrites (samples 754, 194, 195) present cryptocrystalline cement with numerous micritic ovoidal-spheroid pellets. The small size pellets are predominant. Additionally, sparry calcite clasts with mi critic edges are present. The sample 754 taken from the basis of the thin bedded level presents binary sequences of pelmicritmicrosparit type which make the transition to the following microf acies type illustrated by the biomicrosparites (sample 193) above them. Sample 754 typically contains spheroid oncoids with internal concentri c lamination disposed around a nucleus of

PAGE 5

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 91 microsparitic or sparitic calcite or of detritic quartz. Sometimes, such oncoids are joi ned to some sparitic intraclasts. Two cement gene rations are present in this level: radial fibrous and granular. Fig. 4. Succession of the Triassic carbonate deposits from the Piatra oimului klippe (SE slope, behind the Rar u chalet) Bucovinian Nappe: 1-dolosparites, 2dolomicrosparites, Lower Anisian; 3-jaspers, Callovian-Oxfordian. Transylvanian Nappes: 4-microsparites; 5-algal biosparites; 6-pelmicrites; 7-calcareous breccia; 8-stromatolitic limestones; 9-massive limestones; 4-9 LadinianNorian. The pelmicrites discontinuously develop algal-mats made up of flat laminae with peloidal structure. The algal mats incorporate calcareous grains. Algal laminae are also disposed around some calcareous sponges, and algal nodules with incorporated calcareous grains appear quite frequently. The thin, curved filaments, as well as the bryozoan fragments and ostracods are rare. The fossil association consists of Tubiphytes sp. (Pl. IV, Fig. 4) Globochaete alpina LOMBARD and Ladinella porata OTT. The biomicrosparites (sample 193). Neoformated calcite areas as subhedral crystals with brownish impurities betraying their diagenetic change through aggradation are developed in the microcrystalline calcite cement. Some peloidal grains of algal origin are visible as we ll (the spheroid pellets are predominant). The bioclasts are represented by bryozoans fragments, microproblematicae as Tubiphytes , foraminifera belonging especially to the species Earlandia amplimuralis PANTI and Earlandia gracilis ELLIOTT, and some rare dasycladales ( Oligoporella pilosa PIA, Oligoporella sp.) (Pl. I, Fig. 1). Biostratigraphic remarks Oligoporella pilosa PIA is indicative of the PelsonianIllyrian interval. It is cited in specific associations to this stra tigraphic interval in the limestones from Dunav u in North Dobrogea (Dragastan & Gr dinaru, 1975), but especially in

PAGE 6

DANIELA POPESCU, LIVIU POPESCU 92 those in P durea Craiului (Bleahu et al., 1972; Popa & Dragastan, 1973; Dragastan, 1980). The general distribution of this spec ies is Pelsonian-Lower Illyrian (Bucur, 1997). Ladinella porata OTT is typical of the Ladinian from the External Dinarides (Panti 1971-1972, 1973-1974), being also found in the Upper Anisian from the lower part of the Wetterstein limestones in the Apuseni (Mantea, 1985; Dragastan et al., 1982); this species was found also in Lower Carnian (Baltre et al., 1981; Istocescu & Dragastan, 1978; S ndulescu et al., 1976). Earlandia amplimuralis PANTI is described by Panti (1971-1972) in the Ladinian dolomitic limestones from Crna Gora (External Dinarides). S ndulescu & Tomescu (1978) quote it together with a c haracteristic association for the Upper Anisian-Lower Ladinian interval in the limestones of the Botu quarry (the Rar u Syncline). The micropaleontological assemblage we identified in Piatra oimului proves, for the first time, the presence of the PelsonianIllyrian in the basal part of this calcareous klippe. 2. LadinianCarnian microfacies The algal biopelmicrites (samples 195, 196, 200, 201, 203, 206, 207, 757) have the highest frequency on t he northern slope of the Piatra oimului klippe. They have cryptocrystalline cement and contain varied allochems and bioclasts. The allochems with the highest frequency are the micritic pellets with irregular shapes and different sizes, rela tively poorly sorted of a probably algal origin (Flgel, 1982). Sparitic clasts with micritic edges and oncoids with concentric lamination around a microsparitic or sparitic clast are also present. The oncoids have preponderantly ellipsoidal and, in some cases, spher oid shapes. Sometimes in the pelmicritic matrix of the limestones, sparitic areas are present (samples 207, 757) and even brecciated areas made up of large crystallysed calcitic clasts accompanied by smaller clasts of twinned dolomite (sample 201). The most frequent bioclasts are those of cyanobacterial origin. The algalmicrobial material is disposed in thin crusts around some bioclasts, some intraclasts, etc. In most of the cases, siltic quartz grains are also trapped among the cyanobacterial filaments. The cyanobacterial ma terial is present also in clasts with spheroid aspects as well as nodular forms with irregular outline and internal skeleton preserved as tubular filaments ( Porostromata ). The following algal assemblage was determinated: Macroporella sp ., Ladinella porata OTT (Pl. I, Fig. 5), Globochaete alpina LOMBARD. Beside algae (Pl. I, Fig. 3), rarely ostracods (Pl. III, Fig. 5; Pl. VI, Fig. 3), brachiopods, hydrozoans, bryozoans, small gasterop od fragments, worm tubes (Pl. III, Fig. 6) and Incertae sedis organisms also appear (Pl. V, Fig. 5). The segmented calcisponges ( Sphinctozoa ) (Pl. II, Fig. 5) are represented by: Cryptocoelia zitteli OTT (Pl. I, Fig. 5), Uvanella irregularis OTT and Dictyocoelia manon M NSTER. Foraminifera are represented by several exemplaries of Duostominidae Some foraminifera have the interior of the test filled with small pellets, which outline their contour after a previous dissolution of the internal structure. Among these were

PAGE 7

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 93 determined: Ophthalmidium cf exiguum KOEHN-ZANINETTI (Pl. III, Fig. 2), Earlandia amplimuralis PANTI (Pl. III, Fig. 3) and Earlandia gracilis ELLIOTT. The last two species are trapped in the ti ssu of some algae of the Solenopora type (Pl. I, Fig. 4). The algal biopelsparites (samples 197, 313) contain about the same allochems and bioclasts as the previous type, except for the matrix which is microcrystalline. Beside t he above presented bioclasts, in these limestones also appear: nodules of Tubiphytes type, filaments, echinoderm fragments with microbial crusts. Among the determined forms we mention Ophthalmidium exiguum KOEHNZANINETTI (Pl. III, Fig. 1) and Cryptocoelia zitteli OTT (Pl. II, Fig. 2). In one sample (197) two cement generations appear, with different crystal morphology reflecting different mineralogical composition. The first generation consists of radial-fibrous calcite cement precipitated in marine environment. The former aragonitic cement of the rock was probably dissolved and replaced by calcite. The recrystallisation processes are proved by the isolated presence of the radial-fibrous structure (Pl. VI, Fig. 5). The second g eneration is made up of largely crystallised cement that was precipitated in reducing conditions during the meteoric-phreatic or burrial diagenesis (Adams & Mackenzie, 1998). The pelintramicrites (samples 311, 312) correspond to the calcareous breccia from the south-east ern slope of the Piatra oimului klippe. The pelmicritic mass contains sparitic intraclasts, ellipsoida l oncomicrites (Pl. IV, Fig. 2) with concentric laminations and diagenised algae. The clorophycean algae are represented by Diplopora annulata SCHAFHUTL. The microbial structures of the Baccanella floriformis PANTI type are frequent (Pl. V, Fig. 1). They are accom-panied by some samples of Tubiphytes (Pl. IV, Figs. 1, 3) and rare Incertae sedis microorganisms (Pl. V, Fig. 3). This microfacies is typical of the shallow subtidal and probably protected portions of the Triassic reefs. The pelmicrosparites (sample 199) are characterized by micritic algal pellets. Slightly curved biva lve shells show micritic envelopes and are cemented by granular sparite. Algal material is rarely present. The microsparites (sample 308) appear in the lower part of the thin bedded level at the base of the eastern slope of the klippe. It presents sparitic fenestrae and is devoid of bioclasts. The sparites (samples 204, 205, 309) are made up of large euhedral and subhedral calcite crystals with impurities of probably clay minerals. The crystals are yellow-brown and present numer ous striations caused by the pressure. The brown colour is typical of the carbonate minera ls that underwent diagenetic processes. One of the thin sections (204) contains a micritic area in which the cyanophyticalgal material is abundant. It is made up of laminae disposed almost parallel on the surface of some dasycladales. The sparite was formed throught the gradual recrystallization of a micritic sediment with algae (Pl. V, Fig. 1). The only identified bioclasts are some nodules of the Tubiphytes type encrusted by Ladinella porata OTT (sample 309) (Pl. I, Fig. 6). The biosparites (sample 198), as the biomicrites (sample 202), are characterised by the abundance in microbial material (Pl. V, Fig. 2) which covers some carbonate lithoclasts, ostracods and diagenesed dasycladales. Algal structures are also present. Among the determined forms we mention Dictyocoelia manon MNSTER (sample 198) and Uvanella irregularis OTT (Pl. II, Figs. 3, 4).

PAGE 8

DANIELA POPESCU, LIVIU POPESCU 94 Biostratigrafic remarks The Piatra oimului klippe offered some Daonella specimens (Mutihac, 1968) of which Turcule (1972) describes only one species of Daonella (Moussonella) cf moussoni MR typical for Ladinian. Turcule (1971) quoted from the same klippe two species of sponges: Colospongia dubia MNSTER var. pectusa KLIP and Colospongia dubia MNSTER var. pustulipora TOULA. In the Northern Alps these species are described in the Ladinian-Carnian interval. All the algal species we identified have their maximum of evolut ion in Ladinian, being also quoted in Cordevolian. The same stratigraphic interval, Ladini anCordevolian, is proved by the existence of the three species of sphinctozoa: Dictyocoelia manon MNSTER, Cryptocoelia zitteli OTT and Uvanella irregularis OTT (Dragastan & Gr dinaru, 1975; Istocescu & Dragastan, 1978; Panti 1971-1972). Uvanella irregularis OTT and Ophthalmidium exiguum KOEHNZANINETTI show the presence of the Ladinian and of the entire Carnian from the Insula Popina (Baltre et al., 1981). In the Western Carpathians, the last species has a stra tigraphic range limited only to the Lower Carnian (Gazdzicki et al., 1978). Salaj et al. (1983) quoted the same species in the Ladinian-Carnian from the Calcareous Northern Alps, Italian Alps, the Bakony Mountains (Hungary), Helenides, Balcans an d Caucasus; in the Slovak Karst this species was found in Carnian and Norian deposits. As a conclusion, the micropaleontologi cal association we identified in two thirds of the limestones of the Piatra oimului klippe is characteristic for the LadinianLower Carnian. In the south-eastern slo pe, even if the species determined are not so diverse, we can assign the thin bedded limestones, the white siliceous limestones and the breccia level to the Ladinian and the Cordevolian. The following stromatolitic limestone and the overlying massive lime stones could be assigned to the JulianTuvalian and to the Norian, respectively only based on stratigraphic criteria. 3. Norian Microfacies Of the two types of Norian microfacies, the micrites (samples 759, 760) are the most frequent and completely lacking microfauna. The intramicrites (sample 208) present large diagenetically modified calcite granoclasts with multiple twinnings and striations. Microsparitic intraclasts and diverse bioclasts (pseudopunctate brachiopods (Pl. VI, Fi g. 4), sponges (Pl. II, Fig. 6), echinoids spines, bryozoans (Pl. III, Fig. 4), and numerous dasyclad fragments) and Incertae sedis (Pl. V, Fig. 6) are surrounded by the micritic matrix. Sometimes the recrystallisation of some dasyclad algae marks their determination impossible. We identified a single species of foraminifera: Ophthalmidium exiguum KOEHNZANINETTI (Pl. III). Biostratigrafic remarks The presence of the Norian in the Piatra oimului klippe was proved by Patrulius (1970) and Patrulius et al. (1971) through the determination of the algae Gryphoporella curvata G MBEL, Gyroporella aff. vesiculifera G MBEL and Macroporella (Pianella) aff sturi BYSTRICKY (i.e. Salpingoporella sturi ).

PAGE 9

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 95 Salpingoporella sturi is quoted in the entire Carnian from the Slovak Karst (Bystricky, 1967 a, b) and, respectively in the Lower and Middle Tuvalian from the Western Carpathian s (Bystricky, 1979). Gyroporella vesiculifera G MBEL covers the entire Upper Triassic. It was recorded in the Carnian of the Apuseni (Dragastan et al., 1982) and the External Dinarides (Panti 1973974) and the Rhaetian from the Muran Plateau (Bystricky, 1967 a). Herak et al. (1967) identified Gryphoporella curvata G MBEL and Gyroporella vesiculifera G MBEL in the Norian of the External Dinarides (Croatia). Consequently, the association quoted by Patrulius (1970) and Patrulius et al. (1971) indicates the presence of the Norian. PALEOGEOGRAPHIC IMPLICATIONS The sedimentary deposits of the Tran sylvanian unit are lithologically almost exclusively represented by carbonat e pelagic deposits. Many authors (S ndulescu, 1968, 1969, 1972, 1973, 1974, 1975, 1976; Mutihac, 1966a, b, 1968, 1969, 1970, 1990; Ilie, 1957; Patrulius, 1966, 1967, etc.) re marked the presence of many facies types especially at the Triassic level, wh ich is an evidence for variable morphology of the source area of the Transylvanian sedimentary depo sits. The characteristic feature of these sedimentary deposits consis ts in their association with ophiolitic volcanic material. This is an evidence that the Transylvanian sedimentary deposit was formed in a labile expansion area with oceanic crust (S ndulescu, 1984; Mutihac, 1990; Grasu et al., 1995). The sedimentation of the Bucovinian Triassic from the Rar u Syncline, and actually from the entire Crystalline Meso zoic Area of the Eastern Carpathians corresponds in part to the rifting stage with a breaching subsidence type (Grasu et al., 1995). The presence of the limestones klippes over the sedimentary deposits of the Bucovinian Nappe or comprised in the Wildflysh Formation (HauterivianAlbian) account for the existence of a carbonate platform. As a consequence, during the Triassic existed in the same time two different sedimentation domains: the Bucovinian domain and, the Transylvanian domain sit uated westward to the previous. In both domains the sedimentation took place on very large shallow water, predominantly carbonate platforms. The klippes resulted from the fragmentation of the Transylvanian Platform. Subsequently, the klippes were embedded through gravitational slidings in the deposits of the Bucovinian Nappe. Many of the klippes are included in the most recent formation of the Bucovinian Nappe, respectively the wildflysh. The Piatra oimului klippe is situated on the Callo vian-Oxfordian jaspers, which are stratigraphically in a lower position in resp ect to the wildflysh. This suggests that the Piatra oimului klippe was probably put in place during the Upper Jurassic. The detailed description of the vari ous microfacies types allows the reconstitution of the environmental factors in which were formed the deposits of the Piatra oimului klippe. The predominance of micrites and biomicrites indicates a low energy depositional environment, although very weak currents may lead to a slight reworking of the calcareous mud. With more intense currents, the grains remain poorly sorted, resulting in unsorted biosparite.

PAGE 10

DANIELA POPESCU, LIVIU POPESCU 96 The lithofacies analyses must be corobo rated with the study of the micropaleontological content. The presence of the different organic debris -dasycladales algae ( Oligoporella, Diplopora, Macroporella ) and solenoporacean algae ( Solenopora ), foraminifera ( Earlandinidae, Duostominidae, Ophthalmiidae ), sphynctozoa ( Uvanella irregularis, Cryptocoelia zitteli, Dictyocoelia manon ), small gasteropods, bivalves, ostracods, brachiopods etc., as well as of some allochems (pellets, oncoids, intraclasts) show that the limestones of the Piatra oimului klippe were formed in an internal shallow subtidal sector of a ca rbonate platform, in a tropical-subtropical climate. Many of the quoted fossil organisms are indices of the environmental factors. The algae, for example, indicate light and salinity, as they live in calm or little agitated, clear and shallow waters (under 10 m). The stromatolitic level from the south-eastern slope of the klippe is also indicative of a very shallow sediment ation area. The level has plane morphology, each lamina being the result of the cyanoba cterial action at the sediment-water interface. Acknowledgments. We are especially grateful to Prof. Dr. Ioan Bucur from Department of Geology (Babe -Bolyai University, Cluj Napoca) for very helpful suggestions and for the English revision. R E F E R E N C E S Adams, A. E., Mackenzie, W.S. 1998, A Colour Atlas of Carbonate Sediments and Rocks under the Microscope Manson, London, 180 pp. Baltre A., Mir u E. & Gheorghian, D. 1981, The Tria ssic limestones from Popina Island, North Dobrogea. D. S. Inst. Geol. Geofiz ., LXVI (1979): 89-108. Bleahu, M., Tomescu, C. & Panin, 1972, Contribu ii la biostratigrafia depozitelor triasice din Platoul Va c u (Mun ii Apuseni). D. S. Inst. Geol. Geofiz ., LVIII/3 (1971): 5-26. Bucur, I. I. 1997, Rvision de la varit pilosa Pia ex Bystricky, 1964, de lespce Oligoporella pilosa Pia 1912, une algue dasycladace de lAnisien. Rvue de Palobiologie 16/1: 181-186. Bystricky, J. 1967a, Die obertriadisc hen Dasycladaceen der Westkarpaten. Geol. Carpathica XVIII/2: 285-310. Bystricky, J. 1967b, bersicht der Stratigraphie und Entwiklung der Trias in den Westkarpaten. Geol. Carpathica XVIII/2: 257. Bystricky, J. 1979, Dasycladaceae of the Upper Triassic of the Stratenska Hornatina M ountains ((The West Carpathians). Geol.Carpathica 30/3: 321-340. Dragastan, O. & Gr dinaru, E. 1975, Asupra unor alge, foraminifere, sphinctozoare i microproblematice din Triasicul din Carpa ii Orientali i Dobrogea de Nord. St. cerc. geol., geofiz., geogr., Geol. 20/2: 247-254. Dragastan, O. 1980, Alge calcaroase din Mezozoicul i Ter iarul Romniei Ed. Acad. Bucure ti, 167 pp. Dragastan, O., Diaconu, M., Popa, E. & Damian, R. 1982, Biostratig raphy of the Triassic formations in the East of the P durea Craiului Mountains. D. S. Inst. Geol. Geofiz ., LXVII/4 (1979-1980): 29. Flgel, E., 1982, Microfacies analysis of limestones Springer-Verlag, Berlin, 633 pp.

PAGE 11

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 97 Gazdzicki, A., Kozur, H., Mock, R. &Trammer, J. 1978, Triassic microfossils from the Korytnica Limestones at Liptovska Osada (Slova kia) and their stratigraphic significance. Acta Palaeont. Polonica, 23/3: 351-373. Grasu, C., Catana, C., Turcule I. & Ni M. 1995, Petrografia mezozoicului din Sinclinalul marginal extern. Ed. Acad. Rom., Bucure ti, 190 pp. Herak, M., Soka B. & cvni ar, B. 1967, Correlation of the Triassic in SW Lika, Paklenica and Gorski Kotar (Croatia). Geologica Carpathica XVIII/2: 189-202. Ilie, M. 1957, Cercet ri geologice n regiunea Rar uCmpulungul MoldoveiPrul Cailor. An. Com. Geol. Rom., XXIV: 107-211. Istocescu, D. & Dragastan, O. 1978, Les o ccurrences triasiques du bassin de Beiu (Monts Apuseni). D. S. Inst. Geol. Geofiz LXIV/4: 137-145. Krutner, Th. 1929, Cercet ri geologice n cuveta marginal mezozoic a Bucovinei cu privire special la regiunea Rar ului An. Inst. Geol. Rom ., XIV: 1-30. Mantea, G. 1985, Geological Studies in the Upper Bassin of the Some ul Cald Valley and the Valea Seac Valley Region (Bihor-Vl deasa Mountains). An. Inst. Geol. Rom ., 66: 5-89. Mir u E. & Gheorghian, D. 1978, tude microfaunique des formations triasiques (transylvaines, bucoviniennes et gtiques) des Carpates Orientales. D. S. Inst. Geol. Geofiz LXIV/3 (1976-1977): 109-162. Mutihac, V. 1966a, Noi puncte fosilifere triasice n sinclinalul Rar ului. D. S. Inst. Geol. Geofiz LII (1964-1965): 291-297. Mutihac, V. 1966b, Probleme de stratigrafie i tectonic privind sinclinalul Rar ului (Carpa ii Orientali). Stud. cerc., geol., geofiz., geogr., 11/2: 483-496. Mutihac V. 1968, Structura geologic a sinclinalului marginal extern Ed. Acad. Romne, Bucure ti, 104 pp. Mutihac, V. 1969, Structura geologic a sinclinalului marginal extern la nord de Valea Moldovei (Rar u). D. S. Inst. Geol. Geofiz., LIV/3 (1966-1967): 213-225. Mutihac, V. 1970, Evolu ia zonei central-carpatice n orogeneza alpin Stud. cerc., geol., geofiz., geogr. 15/2: 469-479. Mutihac, V. 1990, Structura geologic a teritoriului Romniei Ed. Tehn ., Bucure ti, 419 pp. Mutihac, V. & Mir u E. 1964, Observa iuni asupra Triasicului din Rar u. D. S. Inst. Geol.Geofiz ., L/2 (1962-1963): 309-316. Panti S. 1971-1972, Caractristiques micropal ontologiques et biostratigraphiques des sdiments triasiques carbonats du puit SB -2 sur le profil du barrage de la centrale hydrolectrique de Mratinje (Montenegro). Vesnik Geologija 29-30, A: 271-308. Panti S. 1973-1974, Contributions to the stratigraphy of the Triassic of the Frokletije Mountains. Vesnik Geologija 31-32, A: 135-167. Patrulius, D. 1966, Dorsala dolomitic rudiment al Carpa ilor Orientali n timpul Triasicului. D. S. Inst. Geol. Geofiz ., LII/2 (1964-1965): 35-160. Patrulius, D. 1967, Le Trias des Carpates Or ientales de Roumanie. Geologicky Sbornik XVIII/2: 233-244. Patrulius, D. 1970, Inventarul sumar al algelor dasycladaceae triasice din Carpa ii Romne ti. D. S. Inst. Geol. Geofiz., LV/3 (1967-1968): 187-196. Patrulius, D., Bleahu, M., Popescu, E. & Bordea, S. 1971, The Triassic Formation of the Apuseni Mountains and the East Carpathians Bend. Guidebook 8: 1-86. Popa, E. & Dragastan, O. 1973, Alge i foraminifere triasice (Anisian-Ladinian) din estul P durii Craiului (Mun ii Apuseni). St. cerc. geol., geofiz., geogr., Geologie 18/2: 425-442. Popescu, G. & Patrulius, D. 1964, Stratigrafia Cretacicului i a klippelor exotice din Rar u. An. Com. Geol ., XXXIV/2: 73-180. Salaj, J., Borza, K. & Samuel, O. 1983, Triassic foraminifers of the West Carpathians. Geol. Ust. Dion. Stura Bratislava, 213 pp. S ndulescu, M. 1968, Probleme tectonice ale sinclinalului H ghima D. S. Inst. Geol. Geofiz ., LIII/3 (1965-1966): 221-240.

PAGE 12

DANIELA POPESCU, LIVIU POPESCU 98 S ndulescu, M. 1969, Structura geologic a p r ii centrale a sinclinalului H ghima D. S. Inst. Geol. Geofiz. LIV/3 (1966-1967): 228-250. S ndulescu, M. 1972, Considera ii asupra posibilit ilor de corelare a structurii Carpa ilor Orientali i Occidentali. D. S. Inst. Geol. Geofiz ., LVIII/5 (1971): 125-150. S ndulescu, M. 1973, Contribu ii la cunoa terea structurii geologice a sinclinalului Rar u (sectorul central). D. S. Inst. Geol ., LIX/5 (1972): 59-85. S ndulescu, M. 1974, Corelarea seriilor mezozoice din sinclinalele Rar u i H ghima (Carpa ii Orientali ). D. S. Inst. Geol. Geofiz ., LX/5 (1972-1973): 120-142. S ndulescu, M. 1975, Studiul geologic al p r ii centrale i nordice a sinclinalului H ghima (Carpa ii Orientali). An. Inst. Geol. Geofiz., XLV: 1-160. S ndulescu, M. 1976, Contribu ii la cunoa terea stratigrafiei i a pozi iei tectonice a seriilor mezozoice din bazinul superior al v ii Moldovei (Carpa ii Orientali). D. S. Inst. Geol. Geofiz. LXII/5 (1974-1975): 149-176. S ndulescu, M., Tomescu, C. & Iva, M. 1976, Date noi cu privire la microfaciesurile i biostratigrafia forma iunilor mezozoice din Sinclinalul Rar u. D. S. Inst. Geol ., LXII/4: 167-188. S ndulescu, M. & Tomescu, C. 1978, Noi contribu ii la cunoa terea Triasicului seriilor transilvane din sinclinalul Rar u (sectorul Botu -T tarca). D. S. Inst. Geol. Geofiz. LXIV/5 (19761977): 141-151. S ndulescu, M. 1984, Geotectonica Romnei Ed. Tehn ., Bucure ti, 336 pp. Turcule I. 1971, Cercet ri geologice asupra depozitelor jurasice i eocretacice din cuveta Rar u-Breaza. Inst. Geol., St. Teh. Econ., J/10, 140 pp. Turcule I., 1972, Contribu ii la studiul genului Daonella cu privire special asupra faunei de halobiidae ladiniene din regiunea Rar u. Anal. Univ. Ia i II b. geol., XVIII: 115-123. Turcule I., 2004, Paleontologia Triasicului transilvan din Rar u Ed. Arvin Press, 170 pp. PLATES Plate I Fig. 1. ?Oligoporella pilosa PIA, longitudinal section, in microsparry calcite cement. Sample 193e, Pelsonian-Illyrian, X24. Fig. 2, 3. Dasyclad thalli: 2-fragment in longitudinal secti on, in sparry calcite cement, sample 197d; 3-fragment in transverse se ction fragment, in micritic matrix, sample 206; Ladinian-Carnian, X24. Fig. 4. Earlandia amplimuralis PANTI incorporated in an algal structure (? Solenopora ). Sample 203, Ladinian-Carnian, X24. Fig. 5. Ladinella porata OTT and Cryptocoelia zitteli OTT in micritic matrix. Sample 200a, Ladinian-Carnian, X24. Fig. 6. Nodule of Tubiphytes type incrusted by Ladinella porata OTT. Sample 309c, Ladinian-Cordevolian, X24. Plate II Fig. 1, 2. Cryptocoelia zitteli OTT. 1-in micritic matrix, sample 200b; 2-in algal biopelsparite, sample 197f; Ladinian-Carnian, X24. Fig. 3. Dyctyocoelia manon M NSTER in sparry calcite cement. Sample 198c, Ladinian-Carnian, X24. Fig. 4. Uvanella irregularis OTT with algal crusts in micritic matrix. Sample 202, Ladinian-Carnian, X24. Fig. 5, 6. Calcareous sponges with succe ssive algal crusts. 5-sample 195a, LadinianCarnian; 6-sample 208b, Norian, X40.

PAGE 13

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 99 Plate III Fig. 1, 2. Ophthalmidium exiguum KOEHN-ZANINETTI. 1-Sample 313g, X24; 2-sample 757e, X40; Ladinian-Carnian. Fig. 3. Earlandia amplimuralis PANTI and few filaments in pelmicrite. Sample 203f, Ladinian-Carnian, X40. Fig. 4. Bryozoan fragment in micritic ma trix. Sample 208a, Ladinian-Carnian, X24. Fig. 5. Ostracod in pelmicrite. Sample 206a, Ladinian-Carnian, X24. Fig. 6. Worm tubes in pelmicrite. Sample 200, Ladinian-Carnian, X24. Plate IV Fig. 1, 3, 4. -Tubiphytes sp. (microproblematica). 1, 3-Sample 312a, Ladinian-Carnian, 1 x40, 3 X24; 4-sample 754, Pelsonian-Illyrian, X24. Fig. 2. Ellipsoidal oncoid with micriticmic rosparitic nucleus in calcareous breccia. Sample 312b, Ladinian-Carnian, X24. Fig. 5. Oncoid fragment in sparry calcit e cement. Sample 198, Ladinian-Carnian, X24. Fig. 6. Oncoid in pelmicrite with rare ostracods. Sample 200k, Ladinian-Carnian, X24. Plate V Fig.1, 2. Microbial structures: 1 Baccanella floriformis PANTI in calcareous breccia, sample 311c, Ladinian-Carnian, X24; 2 in micritic matrix, sample 202b; Ladinian-Carnian, X24. Fig. 3 6. Incertae sedis: 3,4-in calc areous breccia, sample 312, Ladinian-Carnian, X24; 5-in pelmicrite, sample 203d, Ladini an-Carnian, X24; 6-in intramicrite, sample 208d, Norian, X24. Plate VI Fig. 1. Sparite. Sample 204d, Ladinian-Carnian, X24. Fig. 2. Pelsparite. Sample 313, Ladinian-Carnian, X24. Fig. 3. Pelmicrite with rare ostracods. Sample 754d, PelsonianIllyrian, X24. Fig. 4. Intramicrite with pseudopunctate brachiopods. Sample 208c, Norian, X24. Fig. 5. Two cement generations: radial-fib rous aragonite cement and sparry calcite cement. Sample 197e, Ladinian-Carnian, X24. Fig. 6. Stromatolitic structure. Sa mple 310b, Middle-Upper Carnian, X24

PAGE 14

DANIELA POPESCU, LIVIU POPESCU 100 PLATE I 1 2 3 4 5 6

PAGE 15

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 101 PLATE II 1 2 3 4 5 6

PAGE 16

DANIELA POPESCU, LIVIU POPESCU 102 PLATE III 1 2 2 3 5 6

PAGE 17

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 103 PLATE IV 1 2 3 4 5 6

PAGE 18

DANIELA POPESCU, LIVIU POPESCU 104 PLATE V 1 2 3 4 5 6

PAGE 19

MICROFACIES OF THE TRIASSIC LIMESTONES IN THE PIATRA OIMULUI KLIPPE 105 PLATE VI 1 2 3 4 5 6