Sea Level Changes, Anoxic Conditions, Organic Matter Enrichment, and Petroleum Source Rock Potential of the Cretaceous Sequences of the Cauvery Basin, India

1993 ◽  
Author(s):  
Kuldeep Chandra ◽  
D. S. N. Raju ◽  
P. K. Mishra
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Source Rock ◽  
Sea Level Changes ◽  
Cauvery Basin ◽  
Anoxic Conditions ◽  
Petroleum Source Rock

Molecular fossils inferring Quaternary sea-level changes

2020 ◽  
Author(s):  
Martina Conti ◽  
Martin Bates ◽  
Natasha Barlow ◽  
Richard Preece ◽  
Kirsty Penkman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Sea Level Change ◽  
Sea Level Changes ◽  
Primary Producers ◽  
Chlorophyll Pigments ◽  
Molecular Fossils ◽  
Level Change ◽  
Targeted Analysis ◽  
The Impact

<p>Targeted analysis of organic matter in soils and sediments is useful for evaluating past environmental conditions, as specific compounds may be directly linked to organisms and hence to the conditions in which they inhabited the environment.  Variations in molecular fossil distributions have become a powerful tool for understanding changes in palaeoclimate conditions.  This work uses molecular fossils to give an insight into the impact of transgressive events on primary producers inhabiting the studied basin, and hence a more detailed record of sea-level change.</p><p>The cores studied consisted of unconsolidated immature sediments from the mid-late Pleistocene (< 500,000 years) and the Holocene.  Molecular fossils, such as chlorophyll pigments and lipids, exhibit fluctuations as a response to changes in palaeoenvironmental conditions, providing a useful marker for sea-level changes.  Fluctuations in the pigment and <em>n</em>-alkane distribution reflect changes in primary producer activity, while the GDGT-based index of branched and isoprenoid tetraether lipids (BIT) differentiates between terrigenous and marine organic matter inputs.  Lipids were analysed by GC-FID and HPLC-MS while analysis of chlorophyll pigments was carried out using a new UHPLC-DAD method.</p><p>The results from biomarker analyses show excellent time-resolved agreement with previous lithological and ecological studies, but enabled a more sensitive response of different primary producers to changing conditions to be observed.  The molecular fossils were able to detect the onset and cessation of the studied transgressions earlier than it was possible with microfossil evidence.  Linking the pigment and lipid record with more secure dating will enable a more accurate record of Quaternary relative sea-level change.</p>

scholarly journals Organic geochemical and petrographical characteristics of the major lower cretaceous petroleum source rock (Makhul Formation) in Kuwait - Arabian Gulf

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Fatma K. Bahman ◽  
◽  
Fowzia H. Abdullah ◽  
Abbas Saleh ◽  
Hossein Alimi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Source Rock ◽  
Lower Cretaceous ◽  
Arabian Gulf ◽  
Carbon Isotope Ratio ◽  
Middle Part ◽  
Source Rocks ◽  
Peak Oil ◽  
Rock Composition

The Lower Cretaceous Makhul Formation is one of the major petroleum source rocks in Kuwait. This study aims to evaluate the Makhul source rock for its organic matter richness and its relation to the rock composition and depositional environment. A total of 117 core samples were collected from five wells in Raudhatain, Ritqa, Mutriba, Burgan, and Minagish oil fields north and south Kuwait. The rock petrographical studies were carried out using a transmitted and polarized microscope, as well as SEM and XRD analyses on selected samples. Total organic matter TOC and elemental analyses were done for kerogen type optically. The GC and GC-MS were done as well as the carbon isotope ratio. The results of this study show that at its earliest time the Makhul Formation was deposited in an anoxic shallow marine shelf environment. During deposition of the middle part, the water oxicity level was fluctuating from oxic to anoxic condition due to changes in sea level. At the end of Makhul and the start of the upper Minagish Formation, the sea level raised forming an oxic open marine ramp depositional condition. Organic geochemical results show that the average TOC of the Makhul Formation is 2.39% wt. High TOC values of 6.7% wt. were usually associated with the laminated mudstone intervals of the formation. The kerogen is of type II and is dominated by marine amorphous sapropelic organic matter with a mixture of zoo- and phytoplankton and rare terrestrial particles. Solvent extract results indicate non-waxy oils of Mesozoic origin that are associated with marine carbonate rocks. The formation is mature and at its peak oil generation in its deepest part in north Kuwait.

Sea-level changes control organic matter accumulation in the Longmaxi shales of southeastern Chongqing, China

2020 ◽  
Vol 119 ◽  
pp. 104478
Author(s):  
Chengsheng Jin ◽  
Zhiwei Liao ◽  
Youjun Tang
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Sea Level Changes ◽  
Organic Matter Accumulation

Storm-induced concentration of sulfurized, marine-origin, organic matter as a possible mechanism in the formation of petroleum source-rock

2019 ◽  
Vol 109 ◽  
pp. 808-818 ◽  
Author(s):  
Nicolas Tribovillard ◽  
Hichem Koched ◽  
François Baudin ◽  
Thierry Adatte ◽  
Marion Delattre ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Marine Origin ◽  
Petroleum Source Rock

Relative sea-level changes and organic matter enrichment in the Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formations in the Central Yangtze area, China

2021 ◽  
Vol 124 ◽  
pp. 104809
Author(s):  
Lin Chen ◽  
Shu Jiang ◽  
Ping Chen ◽  
Xiaohong Chen ◽  
Baomin Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
Sea Level Changes ◽  
Upper Ordovician ◽  
Relative Sea Level ◽  
Lower Silurian ◽  
Yangtze Area

DEPOSITIONAL CONDITIONS OF THE NORTHERN ONSHORE PERTH BASIN (BASAL TRIASSIC)

2005 ◽  
Vol 45 (1) ◽  
pp. 262 ◽  
Author(s):  
K. Grice ◽  
R.E. Summons ◽  
E. Grosjean ◽  
R.J. Twitchett ◽  
W. Dunning ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Source Rocks ◽  
Photic Zone ◽  
Diagenetic Alteration ◽  
Green Sulphur Bacteria ◽  
Sulphur Bacteria ◽  
Green Sulphur ◽  
Petroleum Source Rock ◽  
Lines Of Evidence

An oil-source rock correlation has been established for the northern onshore Perth Basin (Western Australia) based on unusual aromatic and polar biomarkers attributed ultimately to a green sulphur bacterial source. Several of these biomarkers have been identified throughout the entire Sapropelic Interval of a proven petroleum source rock intersected within a recently discovered marine Permian- Triassic Perth Basin borehole (Hovea–3) and several Perth Basin crude oils. Today, green sulphur bacteria live in the anaerobic zones of stratified lakes or in marine environments with restricted water circulation, where the upper sulphide limit coincides with the lower limit of oxygen. The presence of photosynthetic pigments and carotenoids of green sulphur bacteria, or their diagenetic alteration products in sediments provide unequivocal evidence for photic zone euxinic conditions in the paleowater column. Multiple lines of evidence for photic zone euxinia and euxinic depositional conditions for the Hovea–3 source rock have been obtained from biomarker analyses. Photic zone euxinia is usually associated with the widespread deposition of organic-matter-rich sediments that constitute important source rocks for petroleum deposits that are being exploited today. With the exception of the Perth Basin, such organic-matter-rich sediments are virtually absent from Upper Permian and Lower Triassic sediments globally. Several lines of evidence indicate localised surface ocean productivity may have played a key role in the deposition of a petroleum source rock at this location, although photic zone euxinia was globally more widespread during the Permian-Triassic Superanoxic Event.

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