Chitinozoan biostratigraphy of the P ídolí Series of the East Baltic.docx

《Chitinozoan biostratigraphy of the P ídolí Series of the East Baltic.docx》由会员分享，可在线阅读，更多相关《Chitinozoan biostratigraphy of the P ídolí Series of the East Baltic.docx（20页珍藏版）》请在第一文库网上搜索。

1、Estonian Jourcd of Ecirth Sciences 2011, 6Q 4 191-206The distribution of Pridoll chitinozoans in differentlocalities worldwide is discussed in numerous publi-cations, for example Eisenack (1955, 1972), Wrona(1980), Paris (1981), Paris et aL (1981), Paris & Kriz(1984), Jaglin (1986), KrizetaL (1986),

2、 Verniers et al(1995), Paris & Grahn (1996), Miller et al. (1997),Bounendjel (2002), Jaglin & Paris (2002), and Grahn(2005, 2006). Part of the species described in the above-named papers have been established also in the EastBaltic core studied for this paperThe diversity of Silurian chitinozoans is

3、 very highIn total more than one hundred chitinozoan species havebeen identied globally from the Pri doli Series (seeGrahn & Paris 2011). Knowledge of the distibution ofPridoll chitinozoans in the East Baltic sections is stillquite incomplete The ai m of the present paper is to fillthis gap and to c

4、orrelate more precisely the East Balticchitinozoan biozones with global biozones (Verniers etaL 1995) and find the stratigraphically most useful taxafor interregional correlationA total of 242 samples (with a weight of 100-300 g)were processed; all but six yielded chitinozoans Thestudied material is

5、 deposited in the Institute of Geologyat Tallinn University of Technology (collection GIT 607).GEOLOGICAL SETTINGDuring the regression of the Palaeobaltic sea in thePri doli Epoch the facies belts in the East Baltic areamigrated south westwards The studied drill resrepresent mostly carbonate deposit

6、s of the open shelexcept from the Dubovskoye core which contains mostlyargillaceous sedi mentary rocks of the deeperwatertransitional facies belt (Fig 1). In the East Baltic areathe Pri doli Series is represented by the Kaugatuma and0hesaare regional stages and is subdivided into severallithostratig

7、raphical unit changing laterally from regionto region (Fig 2). The Aigu Beds, forming the lowerpart of the Kaugatuma Formation in Estonia, are192 sz Skeletal gravelGrey muds and Shoreline八八 and sand- T hy muds y Brackish andFacies boundaries二 Biodetrital caka jj Calcareous- 町 high salinity . . . . B

8、oundary of present reous mud 丁 argillaceous mudextension of rocksFig L Loccition ofw the studied drill cores (black dots). Distribution of etirly Pidoli sedimentary rock and lacies belts of the BedticGulf (modified from Bassett et al 1989). 1, tidal flal/lagoon; 2 shoal; 3 open shelf; 4 transition f

9、rom open to deep shelf; 5 shelfdepressionThe distribution of Pridoll chitinozoans in differentlocalities worldwide is discussed in numerous publi-cations, for example Eisenack (1955, 1972), Wrona(1980), Paris (1981), Paris et aL (1981), Paris & Kriz(1984), Jaglin (1986), KrizetaL (1986), Verniers et

10、 al(1995), Paris & Grahn (1996), Miller et al. (1997),Bounendjel (2002), Jaglin & Paris (2002), and Grahn(2005, 2006). Part of the species described in the above-named papers have been established also in the EastBaltic core studied for this paperThe diversity of Silurian chitinozoans is very highIn

11、 total more than one hundred chitinozoan species havebeen identied globally from the Pri doli Series (seeGrahn & Paris 2011). Knowledge of the distibution ofPridoll chitinozoans in the East Baltic sections is stillquite incomplete The ai m of the present paper is to fillthis gap and to correlate mor

12、e precisely the East Balticchitinozoan biozones with global biozones (Verniers etaL 1995) and find the stratigraphically most useful taxafor interregional correlationA total of 242 samples (with a weight of 100-300 g)were processed; all but six yielded chitinozoans Thestudied material is deposited i

13、n the Institute of Geologyat Tallinn University of Technology (collection GIT 607).GEOLOGICAL SETTINGDuring the regression of the Palaeobaltic sea in thePri doli Epoch the facies belts in the East Baltic areamigrated south westwards The studied drill resrepresent mostly carbonate deposits of the ope

14、n shelexcept from the Dubovskoye core which contains mostlyargillaceous sedi mentary rocks of the deeperwatertransitional facies belt (Fig 1). In the East Baltic areathe Pri doli Series is represented by the Kaugatuma and0hesaare regional stages and is subdivided into severallithostratigraphical uni

15、t changing laterally from regionto region (Fig 2). The Aigu Beds, forming the lowerpart of the Kaugatuma Formation in Estonia, are sz Skeletal gravelGrey muds and Shoreline八八 and sand- T hy muds y Brackish andFacies boundaries二 Biodetrital caka jj Calcareous- 町 high salinity . . . . Boundary of present reous mud 丁 argillaceous mudextension of rocksFig L Loccition ofw the