The Mesozoic succession of the eastern Greater Caucasus (Azerbaijan); preliminary fieldwork results and significance for the evolution of the Central Caspian Basin
- The executive companies: Geology Institute
- The year of publication: 2004
- Code: -
- Volumes: total 1 volumes with appendixes in same amount: 2
This report presents field observations of the Mesozoic (Mid Jurassic to Late Cretaceous) section of the eastern Greater Caucasus of Azerbaijan, following a field campaign in October-November 2004. Understanding the Mesozoic geology and evolution of the area is relevant for exploration of the offshore Central Caspian Basin, to the northeast. Preliminary sedimentological and paleontological field results are discussed. The geological context and database of the samples selected for paleontological and heavy mineral sandstone provenance analysis is presented.
The examined Mid Jurassic succession consists of low energy basinal deposits and sandstone turbidites. Clastic deposits are derived from source areas to the north and ?northeast. The Late Jurassic succession, when present, consists of carbonate reefs and associated slope deposits. The Late Jurassic section however is often missing, and an important unconformity separating the Mid Jurassic and Early Cretaceous sections is deduced. Ongoing palaeontological studies will constrain these observations.
The Early Cretaceous succession consists of carbonate distal shelf deposits, grading into Mid Cretaceous forereef deposits and organic-rich shelf/turbiditic deposits. A prominent unconformity, probably of Cenomanian age, separates the mid and Late Cretaceous strata. This erosional event is marked in the southern flank of the Greater Caucasus by widespread volcanic activity. This event can be correlated with similar events in the Lesser Caucasus, where it has been related to reactivation of northward-directed subduction. Late Cretaceous deposits consist of turbiditic distal shelf and basinal deposits.
Sediment provenance during the Jurassic and Cretaceous, from paleocurrent indicators, is from source areas to the north-northeast in the northern Greater Caucasus. Provenance is however from the south during the mid and Late Cretaceous in the southern flank of the Greater Caucasus anticlinorium. This southern sediment provenance for the mid and Late Cretaceous sediments in the southern flank had not been previously described.
Two major changes in basin evolution, with associated unconformity development, have been identified in the Mid-Late Jurassic to Early Cretaceous, and in the Late Cretaceous (Cenomanian). The main tectono-stratigraphic events identified in the eastern Greater Caucasus are likely to be present in the Central Caspian Basin, given its evolution in a similar tectonic setting, and have an influence on sediment distribution patterns. A preliminary view of the possible facies distribution in the Central Caspian during the Jurassic and Cretaceous, based on fieldwork observations, is given. Results of ongoing paleontological and provenance analysis, as well as future fieldwork in the Mangystau Mountains of Kazakstan will help constrain these preliminary interpretations.
3 GEOLOGICAL SETTING
4 FIELD GEOLOGY OF THE EASTERN GREATER CAUCASUS
4.1 AREA 1, NORTHERN FLANK. KONAKHKEND-YERFI, Localities 1-31 (Panels 1-6)
4.1.1 Mid Jurassic (Panel 3)
4.1.2 Late Jurassic section (Panel 6)
4.1.3 Early Cretaceous section (Panel 2, 4, 6)
4.1.4 Mid Cretaceous section (Panel 2, 5, 6)
4.1.5 Late Cretaceous (Panel 2, 4)
4.2 AREA 2, NORTHERN FLANK. CHIRAX-GIULE, Localities 32-40 (Panels 7, 8)
4.2.1 Mid Jurassic
4.2.2 Late Jurassic (Early Cretaceous)
4.3 AREA 3, NORTHERN FLANK. ALTYAGACH, Localities 41-50 (panel 9, 10)
4.3.1 Mid Cretaceous
4.3.2 Late Cretaceous
4.4 AREA 4, SOUTHERN FLANK. LAGICH, Localities 50-53 (Panels 11, 12)
4.4.1 Mid Cretaceous
4.4.2 Late Cretaceous
5 GEOLOGICAL EVOLUTION: DISCUSSION
7 ONGOING ANALYSIS AND FUTURE WORK