Extended Abstract: Re‐os Geochronology and Chemostratigraphy of the Maikop Series Source Rocks of Eastern Azerbaijan

Abstract

The Oligocene – Miocene Maikop Series is a world‐class source interval and is the most important source rock for the petroleum systems of the South Caspian Basin and surrounding region. The Maikop is a thick (up to 3 km) succession of silty mudstones with intervals of high organic carbon content. However correlation of organic‐rich intervals within the South Caspian Basin and beyond to basins of the Eastern Paratethys is problematic. Current age constraints are based primarily on microfaunal assemblages, but the assemblages are lacking in precision and are sparsely dispersed. This study provides a numerical age datum for Maikopian strata that may be used to improve correlation of organic‐rich intervals both locally and regionally. The age date obtained was produced via Re‐Os isotope geochronology. Of the five sample suites analyzed, one Re‐Os data‐set yielded an isochron of 17.2 ± 3.2 Ma. Re‐Os data sets that failed to produce statistically meaningful isochrons provide qualitative age constraints by comparing calculated initial 187Os/188Os ratios from these samples to187Os/188Os ratios in seawater through time.

New Geochemical Insights Into Cenozoic Source Rocks in Azerbaijan: Implications for Petroleum Systems in the South Caspian Region

“…Member A is the thickest unit and is rich in secondary jarosite on weathered surfaces in outcrops giving it a whitish to yellow colour in the field. Samples from the uppermost part of member A on the eastern slope of Mount Islamdag yielded a Re-Os age of 17.2 ± 3.2 Ma (Washburn et al, 2018;. The age fits within the error range of the postulated early Miocene (Sakaraulian) age of the upper part of member A of the Maikop Group (Popov et al, 2008).…”

“…The Maikop Group is dominated by laminated noncalcareous mudstones and claystones. These sediments have been studied previously using palynomorphs, calcareous phytoplankton and fish fossils (Popov et al, 2008) as well as rhenium-osmium (Re-Os) geochronology (Washburn et al, 2018;. Whereas calcareous (benthic) fossils are largely absent, fish remains are common.…”

Constraining the Timing and Depositional Conditions of the Maikop Formation Within the Kura Basin, Eastern Azerbaijan, Through the Application of Re‐os Geochronology and Chemostratigraphy

“…Re-Os geochronology was used to obtain a numerical age date for the samples, and regional stratigraphic constraints were investigated using geochemical signatures and Re-Os isotope data. Some of this data has previously been presented in an extended Abstract (Washburn et al, 2018). Popov et al, 2008;Hudson et al, 2008;Johnson et al, 2009).…”

“…An age date of ~17.2 Ma for the lower Islamdag sample suite (Fig. 8a) provides a reference datum for the bio-, chemo-, chrono-and lithostratigraphic data which has previously been collected throughout the basins (Washburn et al, 2018). This age date A, B, C).…”