MICROPALEOTOLOGICAL ASSEMBLAGES AND MICROFACIES CHARACTERISTICS OF THE by crg20831

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									ACTA PALAEONTOLOGICA ROMANIAE V. 4 (2004), P 475-484


    MICROPALEOTOLOGICAL ASSEMBLAGES AND MICROFACIES CHARACTERISTICS OF THE
        UPPER JURASSIC LIMESTONES FROM CĂPRIOARA-POJOGA (MUREŞ TROUGH)

                                  DIANA ŞERBAN1, IOAN I. BUCUR1 & EMANOIL SĂSĂRAN1

       Abstract. The study provides a review of the fossil micropaleontological associations and the main
       microfacies features of the Upper Jurassic limestones (Stramberk-type facies) from Căprioara-Pojoga (Mureş
       Trough). Based on samples collected from three profiles, the micropaleontological content was investigated in
       the view of establishing the age of the limestones. The identification of the main microfacies types and
       sedimentary structures lead to the reconstruction of the sedimentary evolution of the carbonate platform in
       this area.
       Keywords: carbonate microfacies, microfossils, Upper Jurassic, Căprioara (Mureş Trough), Romania.


LOCATION GEOLOGICAL BACKGROUND                                  sponge bioconstructions with Nipponophycus
                                                                ramosus YABE & TOYAMA (Pl.IV, fig.3),
    The investigated Upper Jurassic deposits
                                                                „Tubiphytes” morronensis CRESCENTI, Radiomura
consisting of Stramberk-type limestones are located
                                                                cautica SENOWBAI-DARYAN & SCHAEFFER
along the left side of Mureş valley, 80 km from Deva
                                                                (Pl.IV, fig.16), and Lithocodium aggregatum
town. Within the geological structure of the region,
                                                                ELLIOTT, encrusting corals. The sediment between
these deposits outline as an east-west- oriented,
                                                                the build-ups is represented by bioclastic packstone
clearly individualized massif between Caprioara and
                                                                and grainstone with bryozoans, coral fragments,
Pojoga villages (Fig.1). The outcropping Stramberk-
                                                                echinoids, bivalves and Clypeina sulcata (ALTH),
type limestones are folded into an asymmetrical, NE-
                                                                Salpingoporella johnsoni (DRAGASTAN) (Pl.III,
SW- oriented syncline, 12 km in length and 1-2.5 km
                                                                fig.6), Salpingoporella pygmaea (GUEMBEL),
in width.
                                                                Anisoporella? jurassica (ENDO) (Pl.IV, fig.2),
    During Upper Jurassic, favourable conditions in
                                                                rivulariacean-like cyanobacteria, Mercierela dacica
the area favoured the development of a carbonate
                                                                (DRAGASTAN),             Nipponophycus         ramosus,
platform, on a basement consisting of jaspers and
                                                                „Tubiphytes” morronensis, Mohlerina basiliensis
diabases. The present day southern border of the
                                                                (MOHLER) (Pl.IV, fig.14-15), and miliolides.
Stramberk-type limestones approximates the former
                                                                    A gradual transition to granular facies, such as
shoreline. The northern limit of extension of the
                                                                coarse grainstone with coral bioclasts, ooidic
limestones is difficult to define, due to the
                                                                grainstone with Clypeina sulcata (Pl.III, fig.1),
subsequent erosion.
                                                                Salpingoporella pygmea (Pl.III, fig.7-8, Pl.IV, fig.1),
    At the end of Jurassic, due to the tectonic
                                                                Salpingoporella grudii RADOIČIĆ (Pl.III, fig.2),
movements of the Eokimmeric phase, an intense
                                                                Salpingoporella annulata CAROZZI (Pl.III, fig.5),
uplift was recorded in the whole Carpathian area.
                                                                Anisoporella? jurassica, Andersenolina alpina
This is valid also for the studied area, where the
                                                                (LEUPOLD), Mohlerina basiliensis, Campbeliella
Stramberk-type limestones were emmersed and
                                                                striata CAROZZI (Pl.III, fig.13-14), Mercierela dacica,
slightly folded. As a consequence of the same
                                                                gastropod bioclasts, large agglutinated foraminifera;
movements, a southwards migration of the area of
                                                                slightly granular packstone with nerineid gastropods,
sedimentation took place, marked by the Lower
                                                                corals, foraminifera bioclasts, and algal fragments of
Cretaceous deposits (DUŞA, 1969).
                                                                Dasycladacee (Suppiluliumaella sp.) (Pl.III, fig.12);
SHORT   OUTLOOK            ON     MICROFACIES          AND      ooidic packstone with gastropod and bivalve
MICROFOSSILS                                                    bioclasts, foraminifera [Pseudoyiclamina lituus
   This study is based on the analysis of three                 YOKOYAMA (Pl.IV, fig.9), Andersenolina alpine],
carbonate sections.                                             dasyclads (Cylindroporella sp., Clypeina sulcata) and
   1. The first succession outcrops south from                  rivulariacean-like cyanobacteria can be noticed
Caprioara village (Campul Babei Hill). The                      towards the syncline axis.
succession was samppled from the border of the hill                 In the vicinity of the syncline axis, the frequency
towards the syncline axis. It consists of carbonate             of granular facies decreases, they being gradually
facies represented of reefal build-ups (reef crest              replaced by subtidal facies. The latter are
facies) gradually passing into back reef-type                   represented by bioclastic mudstones and
bioconstructions (Fig. 2). The limestones from                  wackestones with nerineids, rivulariacean-like
Câmpul Babei Hill mainly consist of coral and

1
   Babeş-Bolyai University, Department of Geology, str. M. Kogălniceanu       nr.1,   3400   Cluj-Napoca,   Romania.   E-mails:
serbandia@yahoo.com; ibucur@bioge.ubbcluj.ro; esasaran@bioge.ubbcluj.ro.



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                                              D. ŞERBAN , I.I. BUCUR & E.SĂSĂRAN




      Figure 1 – Location and geology of sketch of Căprioara – Pojoga area (after Duşa, 1968) slightly modified. 1-alluvial
      deposits; 2-Upper Jurassic limestones; 3-Barremian-Aptian deposits; 4-diabase and jaspers.

cyanobacteria, Bacinella irregularis RADOIČIĆ and                  followed by a succession of 5 banks, 40-60 cm
dasyclads, interlayered with fenestral bioclastic                  thickness each; the first bank includes thin layers of
packstones containing gastropods, bivalves, algae                  bioturbated micrites (Pl.I, fig.3); the second one ends
(Clypeina sulcata, Suppiluliumaella sp., Pl.III, fig.10,           with a poorly defined karst surface; the next bank
Salpingoporella annulata, Salpingoporella pygmea,                  has a micritic nature and shows a very-well defined
Thaumatoporella parvovesiculifera, Pl.III, fig.15),                emmersion surface on the top; the upper part of the
rivulariacean-like cyanobacteria, and foraminifera                 fourth bank contains a platy level; the last bank
[Andersenolina alpina, Kurnubia palastiniensis                     consists of micrite;
HENSON, Charentia sp., (Pl.IV, fig.8), Mayncina sp.,                   In the middle part of the quarry outcrop intertidal
Pl.IV, fig.7].                                                     sediments (Pl.I, fig.2, 4-9) represented by a
    2. The second studied succession is located                    succession with fenestral-laminated structure with
along Capriorisca valley, in a quarry 1 km south from              rare dasyclads (Anisoporella? jurassica (ENDO),
Caprioara village. The base of the succession                      Pl.III, fig.11), ending with an emmersion surface
consists of breccia and microbreccia with carbonate                defined by the presence of dissolution breccia.
elements, decimetre-thick. The carbonate fragments                     In the upper part of the quarry, several banks with
are angular to subrounded and are enclosed within a                nerineids develop.
red clayey matrix. The next 10 meters in the vertical                  This succession characterizes a shallow water
succession are covered; but following this gape the                depositional environment. Several sequences
succession is cropping out in the quarry (Fig. 2). The             indicate a gradual tansition from deeper to shallower
quarry is about 30 m high, and evidences the                       facies by the superposition of intertidal and
following succession:                                              supratidal facies on the subtidal ones. This facies
    In the lower part outcrops a basal grainstone and              variation
coarse oncoidic grainstone level with Salpingoporella                  In the upper part of the quarry, several banks with
annulata (Pl.III, fig.3), Salpingoporella sp. (Pl.III,             nerineids develop.
fig.4), rivulariacean-like cyanobacteria (Pl.IV, fig.5)                This succession characterizes a shallow water
and foraminifera        (Bolivinopsis sp, Pl.IV, fig.6;            depositional environment. Several sequences
Charentia       sp.,   Pl.IV,    fig.8; Andersenolina              indicate a gradual tansition from deeper to shallower
delphinensis ARNAUD-VANNEAU, BOISSEAU &                            facies by the superposition of intertidal and
DARSAC, Pl.IV, fig.11; Andersenolina cherchiae                     supratidal facies on the subtidal ones. This facies
ARNAUD-VANNEAU, BOISSEAU & DARSAC, Pl.IV,                          variation could be explaned by the progradation or
fig.12 and Andersenolina elongata (LEUPOLD),                       the lateral migration of the depositional environment.
Pl.IV, fig.13). It is followed by an oncoidal breccia              In most of the cases, the top of the sequences
and coarse grainstone with gastropods and bivalves                 corresponds to paleokarst surfaces with root traces
ending with a thin layer of microbreccia (5 cm).                   and drying cracks (Fig. 3). These features reflect a
Another breccia level (packstone with gastropods, 40               decrease of the sea level. The overlaying deposits
cm thick), and several banks, each 60-70 cm thick                  are represented by limestones with Charhytes (Pl.IV,
(packstone with brecciated features at the top, Pl.I,              fig.4), ostracods, and gastropods indicating a fresh
fig.1) follow in the succession. The sequence                      water supply.
continues with wackstone-packstone, and a level                        3. The samples of the third succession were
consisting of 3-4 very thin packstone layers, each                 collected from Dines valley, west from Pojoga
ending with paleokarst surfaces filled wih red clay,               village, at the eastern extremity of the carbonate

476
  MICROPALEOTOLOGICAL ASSEMBLAGES AND MICROFACIES CHARACTERISTICS OF THE UPPER JURASSIC LIMESTONES
                              FROM CĂPRIOARA-POJOGA (MUREŞ TROUGH)

crest (Fig. 2). The succession evidences a shallow,               encrusting and perforating foraminifera, Radiomura
subtidal to intertidal depositional environment                   cautica (Pl.II, fig.8), „Tubiphytes” morronensis (Pl.II,
consisting of tidal plain deposits, algal mats, and reef          fig.6), Lithocodium aggregatum ELLIOTT (Pl.II, fig.7)
bioconstructions.                                                 and Bacinella irregularis encrusted on corals (Pl.II,
   The succession on Dines valley is dominated by                 fig.5) have been noticed.
build-ups with corals, besides which sponges,




Figure 2 – Limestone succession in the 3 sampled sections: A – Câmpul Babei Hill; B – Căprioara Quarry; C – Dineş
Valley; 1 – oncoids; 2 – breccia; 3 – fenestral limestone; 4 – chert bearing limestone; 5 – algae ; 6 – corals; 7 – gastropods;
8 –observational gap.




                                                                                                                           477
                                             D. ŞERBAN , I.I. BUCUR & E.SĂSĂRAN




      Figure 3 – Paleocarst surface in the Căprioara Quarry section.

    The internal sediment of the bioconstructions is              1999). Among the foraminifera, only Kurnubia
represented by bioclastic packstone and grainstone                palastiniensis is a species restricted to Upper
with bryozoans, coral fragments, bivalves, dasyclads              Jurassic     (SEPTFONTAINE        et  al.,    1991;
(Clypeina sulcata, Salpingoporella pygmaea, Pl.III,               BASSOULLET, 1997a). Andersenolina alpina, and
fig.9), rivulariacean-type cyanobacteria, Mercierela              Mohlerina basiliensis have been frequently identified
dacica, „Tubiphytes” morronensis, and Mohlerina                   in common Upper Jurassic assemblages. All the
basiliensis.                                                      other microfossils, even if common for Upper
    Towards the syncline axis, a gradual change to                Jurassic deposits, they have been also identified in
granular facies consisting of coarse grainstone with              Lower Cretaceous.
coral and gastropodes bioclasts, ooidal grainstone
with Clypeina sulcata, Salpingoporella sp.,                       CONCLUSIONS
Andersenolina alpina, Mohlerina basiliensis, and
                                                                      The present study is based on the investigation of
Mercierela dacica, slightly granular packstone with
                                                                  three carbonate sections. The first section is located
gastropod (nerineids) bioclasts, corals, foraminifera
                                                                  in Câmpul Babei Hill, south of Căprioara village; the
and fragments of dacyclad algae was noticed.
                                                                  second section is located 1 km south of Căprioara
    The microbial carbonate deposits identified in the
                                                                  village, on the Căpriorişca valley, in a quarry, and the
sucession are represented by stromatolitic structures
                                                                  third one on the Dineş valley, 5 km east of Căprioara
(Pl.II, fig.1, 3, 4) including algal mats, thrombolitic
                                                                  village.
crusts (Pl.II, fig.2), oncoids (Pl.III, fig.16) and peloidal
                                                                      The succession sampled in the Câmpul Babei Hill
micrite. The thrombolitic structures are associated
                                                                  consists of reefal build-ups (reef crest facies), which
with encrusting microorganisms („Tubiphytes”
                                                                  progressively pass into back reef facies deposits.
morronensis, Pl.II, fig.6; Radiomura cautica Pl.II,
                                                                      The succession in the quarry was deposited in a
fig.8; Bacinella irregularis and Iberopora bodeuri
                                                                  generally shallow water environment, from shallow
GRANIER & BERTHOU, Pl.II, fig.5)..
                                                                  subtidal to intertidal and supratidal, most of these
                                                                  deposits      representing      shallowing       upward
THE AGE OF THE STRAMBERK-TYPE LIMESTONES
                                                                  parasequences.
    The algal and foraminiferal association identified                The succession on the Dineş valley was formed
in the three studied sections is typical for the Upper            in a subtidal to intertidal shallow water depositional
Jurassic in the Thetys area. Salpingoporella                      environment, with algal mats and more rarely reef-
annulata, S.grudii, S. pygmaea, Clypeina sulcata,                 like bioconstructions. The microbial carbonates of
and Campeliella striata represent a typical                       this succession are represented by stromatolitic
Kimmeridgian-Tithonian association (GRANIER &                     structures, thrombolitic crusts and peloidal micrite,
DELOFFRE, 1993; BASSOULLET, 1997b; BUCUR,                         together with encrusting microorganisms.

478
  MICROPALEOTOLOGICAL ASSEMBLAGES AND MICROFACIES CHARACTERISTICS OF THE UPPER JURASSIC LIMESTONES
                              FROM CĂPRIOARA-POJOGA (MUREŞ TROUGH)

    The micropaleontologic assemblages contain                Acknowledgements.
dasyclad algae and benthic foraminifera indicative
                                                              This paper represents a contribution to the research
for a Late Jurassic (Kimmeridgian-Tithonian) age.
                                                              project financially supported by the grant CNCSIS
                                                              3/1690 (I.I. Bucur)

REFERENCES
BASSOULLET, J.-P. (1997a) - Algues Dasycladales –
  distribution des principales espèces. In: Groupe            DUŞA, A. (1968) – Contribuţii la cunoaşterea stratigrafiei şi
  Français      d’Étude   du    Jurassique     (1997).    –     faunei Jurasicului superior (Calcare de Stramberg) de
  Biostratigraphie du Jurassique ouest-européen et              la Căprioara – Pojoga (Jud. Arad). In: Buletinul
  méditerranéen: zonations parallèles et distribution des       Societăţii de Ştiinţe Geologice din R. S. România, X,
  invertébrés et microfossiles. Cariou, E. & Hantzpergue,       p.241-258.
  P. (coord.). – Bull. Centre Rech. Elf Explor. Prod.,        DUŞA, A. (1969) – Stratigrafia depozitelor Mezozoice şi
  Mém.17, p. 339-342.                                           Terţiare de la Căprioara – Coşteiu de Sus. Editura
BASSOULLET, J.-P. (1997b) – Foraminifères – Les                 Academiei Republicii Socialiste România, Bucureşti.
  Grands Foraminifères. In: Groupe Français d’Étude du          159 p.
  Jurassique (1997). –Biostratigraphie du Jurassique          GRANIER, B., DELOFFRE, R. (1993) – Inventaire critique
  ouest-européen et méditerranéen: zonations parallèles         des algues dasycladales fossiles IIº partie. Les algues
  et distribution des invertébrés et microfossiles. Cariou,     dasycladales du Jurassique et du Cretace. Revue de
  E. & Hantzpergue, P. (coord.). – Bull. Centre Rech. Elf       Paléobiologie, 12, n.1, p. 19-65.
  Explor. Prod., Mém.17, p. 293-304.                          SEPTFONTAINE,         M.,     ARNAUD-VANNEAU,            A.,
BUCUR I.I. (1999) – Stratigraphic significance of some          BASSOULLET, J.-P., GUSIC, Y., RAMALHO, M.,
  skeletal algae (Dasycladales, Caulerpales) of the             VELIC, I. (1991) – Les foraminifères imperforés des
  Phanerozoic. In: Farinacci A. & Lord R. (eds.)                plates-formes carbonatées jurassiques: état des
  Depositional Episodes and bioevents, Palaeopelagos            connaissances et perspectives d’avenir. In: Bulletin de
  Special Publication nr.2, Roma, p.53-104.                     Géologie Lausanne, 312, p. 255-277.

PLATES
PLATE I
CAPRIOARA QUARRY
  Fig.1. Peloidal packstone. Fenastral cavity with geopetal sediment Sample 7018, X20
  Fig.2. Fenestra filled with siltic sediment. Sample 7040, X20
  Fig.3. Bioturbation filled with geopetal sediment in a micritic limestone. Sample 7033, X20
  Fig.4. Peloidal packstone with small fenestrae. Sample 7037A/3, X20
  Fig.5. Peloidal packstone wih laminoid fenestrae. Sample 7043, X20
  Fig.6. Fenestral mudstone. Sample 7047, X20
  Fig.7. Packstone/wackestone with laminoid fenestrae. Sample 7057, X20
  Fig.8. Granular packstone with fenestrae. Sample 7056, X20
  Fig.9. Peloidal, slightly laminated packstone/grainstone. Sample 7038, X20
PLATE II
   Dines Valley
   Fig.1. Peloidal stromatolit (detail). Sample 458, X40
   Fig.2. Peloidal trombolit (detail). Sample 461, X20
   Fig.3, 4. Peloidal stromatolits. Sample 463, X20
   Fig.5. Bacinella irregularis RADOIČIĆ and Iberopora bodeuri GRANIER & BERTHOU. Sample 479, X75
   Fig.6. “Tubiphytes” morronensis CRESCENTI. Sample 453, X40
   Fig.7. Lithocodium aggregatum ELLIOT. Sample 479, X95
   Fig.8. Radiomura cautica. Sample 453, X35
PLATE III
   Fig.1 Clypeina sulcata MASLOV.Campul Babei Hill. Sample 7072, X70
   Fig.2. Salpingoporella grudii (RADOICIC). Campul Babei Hill.Sample 7142, X80
   Fig.3. Salpingoporella anullata CAROZZI. Caprioara Quarry. Sample 7004/1, X175
   Fig.4. Salpingoporella sp. Caprioara Quarry. Sample 7007, X70
   Fig.5. Salpingoporella anullata CAROZZI. Campul Babei Hill. Sample 7096, X75
   Fig.6 Salpingoporella johnsoni DRAGASTAN.Campul Babei Hill. Sample 7114, X175
   Fig.7. Salpingoporella sp. Campul Babei Hill. Sample 7082, X100

                                                                                                                       479
                                      D. ŞERBAN , I.I. BUCUR & E.SĂSĂRAN

      Fig.8. Salpingoporella pygmea (GÜMBEL, 1891) BASSOULET et.al. Campul Babei Hill. Sample 7137, X75
      Fig.9. Salpingoporella pygmea (GÜMBEL, 1891) BASSOULET et.al. Dines Valley. Sample 485, X110
      Fig.10. Suppiluliumaella sp. Campul Babei Hill. Sample 7082, X35
      Fig.11. Anisoporella jurassica (ENDO). Caprioara Quarry. Sample 7051, X65
      Fig.12. Suppiluliumaella sp. Campul Babei Hill. Sample 7147, X25
      Fig.13. Campbeliella striata CAROZZI. Campul Babei Hill. Sample 7150, X60
      Fig.14 Campbeliella striata CAROZZI. Campul Babei Hill. Sample 7158, X30
      Fig.15. Thaumatoporella parvovesiculifera RAINERI. Campul Babei Hill. Sample 7096, X40
      Fig.16. Oncoid with nubeculariid foraminifera. Dines Valley. Sample 493, X15
PLATE IV
      Fig.1. Salpingoporella pygmea (GÜMBEL, 1891). Campul Babei Hill. Sample 7080, X100
      Fig.2. Anisoporella jurassica (ENDO). Campul Babei Hill. Sample 7132, X60
      Fig.3. Nipponophycus ramosus YABE & TOYAMA. Campul Babei Hill. Sample 7110, X50
      Fig.4. Charophyte. Caprioara Quarry. Sample 7022/1, X110
      Fig.5. Rivulariacean like cyanobacteria. Caprioara Quarry. Sample 7004/1, X60
      Fig.6. Bolivinopsis sp. Caprioara Quarry. Sample 7004/2, X120
      Fig.7. Mayncina sp.. Campul Babei Hill. Sample 7074, X120
      Fig.8. Charentia sp. Caprioara Quarry. Sample 7006/3, X135
      Fig.9. Pseudocyclammina lituus. Campul Babei Hill. Sample 7161, X35
      Fig.10. ? Rectocyclammina sp.. Campul Babei Hill. Sample 7085, X50
      Fig.11. Andersenolina delphinensis ARNAUD-VANNEAU, BOISSEAU & DARSAC. Caprioara Quarry.
      Sample 7006/3, X110
      Fig.12. Andersenolina cherchiae ARNAUD-VANNEAU, BOISSEAU & DARSAC. Caprioara Quarry. Sample
      7005, X85
      Fig.13. Andersenolina elongata (LEUPOLD). Caprioara Quarry. Sample 7004/1, X60
      Fig.14. Mohlerina basiliensis (MOHLER). Campul Babei Hill. Sample 7141, X115
      Fig.15 Mohlerina basiliensis (MOHLER). Campul Babei Hill. Sample 7129, X105
      Fig.16 Radiomura cautica SENOWBARI-DAYAN & SCHAEFFER. Campul Babei Hill. Sample 7129, X70




480
D. ŞERBAN , I. I. BUCUR & E. SĂSĂRAN   PLATE I




                                           481
D. ŞERBAN , I. BUCUR & E. SĂSĂRAN   PLATE II




482
D. ŞERBAN , I. BUCUR & E. SĂSĂRAN   PLATE III




                                         483
D. ŞERBAN , I. I. BUCUR & E. SĂSĂRAN   PLATE IV




484

								
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