--> Abstract: Jurassic Sequence Stratigraphy in Western Bulgaria, by P. Tchoumatchenco, I. Sapunov, J. Thierry, and C. Durlet; #90942 (1997).

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Abstract: Jurassic Sequence Stratigraphy in Western Bulgaria

TCHOUMATCHENCO, P., I.SAPUNOV, J. THIERRY, and C.DURLET

In 1996-97, investigations, sponsored by the Peri-Tethyan Program, took place on the western part of Bulgarian Moesia, considering the outcrops in the Mihaylovgrad Graben and the Vidin Upswell.

In this area are individualized, two 1st order depositional sequences, called Lower Major Sequence (sechron Hettangian -Bathonian) and Upper Major Sequence (sechron Callovian-Berriasian), separated by a regional omission surface. The Lowstand Systems Tract of the Lower Major Sequence is composed of clays and sandstones (Bachiiste Formation), sandstones (Kostina Fm.) and bioclastic and sandy limestones and marls (OzirovoFm.); the Transgressiv Systems Tract is built by black shales (Etropole Fm.) - in the Mihaylovgrad Graben and by sandstones (Kichera Fm.) - on the Vidin Upswell. The Highstand Systems Tract is structured by marls (Bov Fm.) - in the Mihaylovgrad Graben, and by marls (Bov Fm.) and sandy limestones (Polaten Fm.) - on the Vidin Upswell. The Lowstand Systems Tract of the Upper Major Sequence is build by micritic limestones (Yavorets Fm.); the Transgressiv Systems Tract - by nodular limestones (Gintsi Fm.), and the Highstand Systems Tract - by intraclastic and micritic limestones (Glozhene Fm.), and reefal limestones (Slivnitsa Fm.). Each systems tract of the Major Sequences coincides with a sequence of 2nd order; in many cases the systems tracts of 2nd order sequences are subdivided into 3rd order sequences; they, into 4th order parasequences.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria