scholarly journals Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4778 ◽  
Author(s):  
Wentong He ◽  
Youhong Sun ◽  
Wei Guo ◽  
Xuanlong Shan ◽  
Siyuan Su ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Cycle ◽  
Depositional Environment ◽  
Global Carbon Cycle ◽  
Songliao Basin ◽  
Oil Generation ◽  
Oil Shales ◽  
Extractable Organic Matter ◽  
The Impact ◽  
Global Carbon

The Cretaceous Era has always been a focus of geologic and palaeoenvironmental studies. Previous researchers believed that the impact of the global carbon cycle represents significant short-term global biogeochemical fluctuations, leading to the formation of a large number of organic rich sediments in the marine environment. During the Turonian, a large number of organic-rich oil shales were deposited in the lakes of the Songliao Basin in the Qingshankou Formation. How the depositional environment affected the formation of oil shales in continental lakes and the characteristics of these oil shales remain controversial. In this paper, through sampling of Qingshankou Formation strata, various testing methods are used to provide a variety of new data to study the characteristics of oil shales and palaeoenvironment evolution history in the Songliao Basin. The research of the sediments in the Qingshankou Formation in the Fuyu oilfield, Songliao Basin, via result analysis revealed that the oil shales possess an excellent oil-generation potential with moderate-high total organic carbon (TOC) levels (0.58–9.43%), high hydrogen index (HI) values (265–959 mg hydrocarbons (HC)/g TOC), high extractable organic matter (EOM) levels (2.50–6.96 mg/g TOC) and high hydrocarbon fractions (48–89%). The sources of the organic matter were mainly zooplankton, red algae and higher plants (including marine organisms). The aqueous palaeoenvironment of the Qingshankou Formation was a saline water environment with a high sulfate concentration, which promoted an increase in nutrients and stratification of the water density in the lake basin. Oxygen consumption in the bottom water layer promoted the accumulation and burial of high-abundance organic matter, thus forming the high-quality oil shales in the Qingshankou Formation. The global carbon cycle, warm-humid palaeoclimate, dynamic local biogeochemical cycling and relative passive tectonism were the most likely reasons for the TOC increase and negative δ13Corg deviation.

Basalt weathering laws and the impact of basalt weathering on the global carbon cycle

2003 ◽  
Vol 202 (3-4) ◽  
pp. 257-273 ◽  
Author(s):  
Céline Dessert ◽  
Bernard Dupré ◽  
Jérôme Gaillardet ◽  
Louis M. François ◽  
Claude J. Allègre
Keyword(s):  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Basalt Weathering ◽  
The Impact ◽  
Global Carbon

scholarly journals The impact of different external sources of iron on the global carbon cycle

2014 ◽  
Vol 41 (3) ◽  
pp. 920-926 ◽  
Author(s):  
Alessandro Tagliabue ◽  
Olivier Aumont ◽  
Laurent Bopp
Keyword(s):  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
External Sources ◽  
The Impact ◽  
Global Carbon

scholarly journals The Impact of Agricultural Soil Erosion on the Global Carbon Cycle

Science ◽  
2007 ◽  
Vol 318 (5850) ◽  
pp. 626-629 ◽  
Author(s):  
K. Van Oost ◽  
T. A. Quine ◽  
G. Govers ◽  
S. De Gryze ◽  
J. Six ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Carbon Cycle ◽  
Agricultural Soil ◽  
Large Scale ◽  
Carbon Sink ◽  
Global Carbon Cycle ◽  
Agricultural Landscapes ◽  
Carbon Equivalent ◽  
The Impact ◽  
Global Carbon

Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year–1to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year–1resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

scholarly journals Oceans May Produce Twice as Much Organic Matter as Usually Measured

Eos ◽  
2017 ◽  
Author(s):  
Sarah Witman
Keyword(s):  
Organic Matter ◽  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Critical Part ◽  
Global Carbon

Researchers study how oceans respire carbon, reexamining a critical part of the global carbon cycle.

scholarly journals An open marine record of the Toarcian oceanic anoxic event

2011 ◽  
Vol 3 (1) ◽  
pp. 385-410 ◽  
Author(s):  
D. R. Gröcke ◽  
R. S. Hori ◽  
J. Trabucho-Alexandre ◽  
D. B. Kemp ◽  
L. Schwark
Keyword(s):  
Organic Matter ◽  
Carbon Cycle ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Global Carbon Cycle ◽  
Open Ocean ◽  
Black Shales ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Global Carbon

Abstract. Oceanic anoxic events were time intervals in the Mesozoic characterized by widespread distribution of marine organic-rich sediments (black shales) and significant perturbations in the global carbon cycle. The expression of these perturbations is globally recorded in sediments as excursions in the carbon isotope record irrespective of lithology or depositional environment. During the Early Toarcian, black shales were deposited on the epi- and peri-continental shelves of Pangaea and these sedimentary rocks are associated with a pronounced (ca. 7‰) negative (organic) carbon isotope excursion (CIE) which is thought to be the result of a major perturbation in the global carbon cycle. For this reason, the Early Toarcian is thought to represent an oceanic anoxic event (the T-OAE). Associated with this event, there were pronounced perturbations in global weathering rates and seawater temperatures. Although it is commonly asserted that the T-OAE is a global event and that the distribution of black shales is likewise global, an isotopic and/or organic-rich expression of this event has as yet only been recognized on epi- and peri-continental Pangaean localities. To address this issue, the carbon isotope composition of organic matter (δ13Corg) of Early Toarcian cherts from Japan that were deposited in the open Panthalassa Ocean was analysed. The results show the presence of a major (>6‰) negative excursion in δ13Corg that, based on radiolarian biostratigraphy, is a correlative of the Early Toarcian negative CIE known from European epicontinental strata. Furthermore, a secondary ca. −2‰ excursion in δ13Corg is also recognized lower in the studied succession that, within the current biostratigraphical resolution, is likely to represent the excursion that occurs close to the Pliensbachian/Toarcian boundary and which is also recorded in European epicontinental successions. These results from the open ocean realm suggest that, in conjunction with other previously published datasets, these major Early Jurassic carbon cycle perturbations affected all active global reservoirs of the exchangeable carbon cycle (deep marine, shallow marine, atmospheric). An extremely negative δ13Corg value (−57‰) during the peak of the T-OAE is also reported, which suggests that the inferred open ocean mid-water oxygen minimum layer within which these sediments are thought to have been deposited was highly enriched in methanotrophic bacteria, since these organisms are the only plausible producers of such 12C-enriched organic matter.

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