Details

Autor(en) / Beteiligte

• Vincent, Stephen J.
• Guo, Li
• Flecker, Rachel
• BouDagher-Fadel, Marcelle K.
• Ellam, Robert M.
• Kandemir, Raif

Titel

Age constraints on intra-formational unconformities in Upper Jurassic-Lower Cretaceous carbonates in northeast Turkey; geodynamic and hydrocarbon implications

Ist Teil von

• Marine and petroleum geology, 2018-03, Vol.91, p.639-657

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Upper Jurassic-lowermost Cretaceous carbonate build-ups are imaged on seismic data in the Black Sea. They form important, untested, hydrocarbon reservoirs that are the focus of active exploration. Outcrop analogues to these build-ups around the Black Sea contain a series of subaerial exposure surfaces. The hiatuses associated with a number of these subaerial exposure surfaces have been dated in a well exposed Callovian or Upper Oxfordian to Barremian shallow-water inner platform carbonate succession (the Berdiga Formation) in the Eastern Pontides using strontium isotope stratigraphy and foraminiferal biostratigraphy. They span the latest Kimmeridgian to Tithonian or Berriasian, and the Hauterivian to Barremian. Less well constrained, but broadly contemporaneous stratigraphic gaps in multiple successions around the Black Sea provide additional insights and point to a regional driving mechanism. The timing of hiatus formation does not correspond to periods of eustatic lowstand. It does coincide, however, with Late Tithonian to Berriasian and Hauterivian to Early Aptian episodes of rifting in the Greater Caucasus Basin, located farther to the north. Thus, it is possible that subaerial exposure was caused by rift flank uplift during periods of regional extension. Uplift due to slab break off is discounted as a control because it post-dates (rather than pre-dates) locally developed Kimmeridgian magmatism. Rift-flank uplift is likely to have also affected carbonate build-ups on the intervening rift shoulders of the eastern Black Sea, the Shatskiy Ridge and the Mid Black Sea High. At outcrop, subaerial exposure is often associated with karstification and secondary porosity development. Similar processes may have occurred in the offshore helping to enhance the reservoir quality of these exploration targets. •Carbonates in the Eastern Pontides are dated using strontium isotope stratigraphy.•The age of a number of hiatuses associated with karstification are also constrained.•These span the latest Kimmeridgian to Berriasian and the Hauterivian to Barremian.•Karstification was likely caused by rift flank uplift during regional extension.•Secondary porosity development is predicted in equivalent strata in the Black Sea.