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Holocene source rock deposition in the Black Sea, insights from a dropcore study offshore Bulgaria

Mohammad Fallah, J. Mayer, G. C. Tari and J. Baur
Holocene source rock deposition in the Black Sea, insights from a dropcore study offshore Bulgaria (in Petroleum geology of the Black Sea, Mike D. Simmons (editor), G. C. Tari (editor) and Aral I. Okay (editor))
Special Publication - Geological Society of London (September 2017) 464 (1): 389-401


One of the main issues in source rock evaluation has always been the availability of thermally immature samples, which would represent the same source rock quality and facies as the mature source rock within the deeper parts of the basin. Forty dropcore sample locations from shallow depths beneath the present-day seafloor were selected and analysed for mineral composition and bulk geochemical parameters. The water depths of the samples range from shelfal to bathyal environments. The quartz content of the samples clearly decreases with increasing distance from sedimentary input sources (e.g. river deltas), whereas clay content increases towards the distal areas. Mass movements (e.g. slides and debris flows) along the present-day shelf are recognizable on the bathymetry, as well as in the mineral content. Bulk geochemical parameters show that currently only poor to fair gas-prone source rocks are deposited within the study area. This lack of source rock quality, as well as organic content, is attributed to the fine-grained sedimentary input from the Danube river. These fine-grained sediments decrease the organic productivity due to dulling (decrease in the thickness of the photic zone) of the water column, and dilute the currently deposited source rock with low TOC sediments. These effects decrease with distance from the Danube delta, as indicated by published data from outside the study area. Additionally mass movements along the present-day shelf rework possible source rocks. The results of this study clearly show that anoxic conditions alone are not sufficient for source rock deposition. Distance from major sedimentary input and basin geometry are of major importance, and should be considered in basin modelling.

ISSN: 0305-8719
Serial Title: Special Publication - Geological Society of London
Serial Volume: 464
Serial Issue: 1
Title: Holocene source rock deposition in the Black Sea, insights from a dropcore study offshore Bulgaria
Title: Petroleum geology of the Black Sea
Author(s): Fallah, MohammadMayer, J.Tari, G. C.Baur, J.
Author(s): Simmons, Mike D.editor
Author(s): Tari, G. C.editor
Author(s): Okay, Aral I.editor
Affiliation: OMV Exploration and Production, Vienna, Austria
Pages: 389-401
Published: 20170915
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 31
Accession Number: 2017-082756
Categories: Sedimentary petrologyEconomic geology, geology of energy sources
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects.
N40°00'00" - N44°00'00", E31°00'00" - E36°00'00"
Secondary Affiliation: Total, FRA, France
Source Note: Online First
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201743
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