scholarly journals The oxic degradation of sedimentary organic matter 1400 Ma constrains atmospheric oxygen levels

2017 ◽  
Vol 14 (8) ◽  
pp. 2133-2149 ◽  
Author(s):  
Shuichang Zhang ◽  
Xiaomei Wang ◽  
Huajian Wang ◽  
Emma U. Hammarlund ◽  
Jin Su ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Carbon Mineralization ◽  
Black Shales ◽  
Depositional Environments ◽  
Iron Speciation ◽  
North China Block ◽  
High Hydrogen ◽  
Oxygen Levels ◽  
The North ◽  
Xiamaling Formation

Abstract. We studied sediments from the ca. 1400 million-year-old Xiamaling Formation from the North China block. The upper unit of this formation (unit 1) deposited mostly below storm wave base and contains alternating black and green-gray shales with very distinct geochemical characteristics. The black shales are enriched in redox-sensitive trace metals, have high concentrations of total organic carbon (TOC), high hydrogen index (HI) and iron speciation indicating deposition under anoxic conditions. In contrast, the green-gray shales show no trace metal enrichments, have low TOC, low HI and iron speciation consistent with an oxygenated depositional setting. Altogether, unit 1 displays alternations between oxic and anoxic depositional environments, driving differences in carbon preservation consistent with observations from the modern ocean. We combined our TOC and HI results to calculate the differences in carbon mineralization and carbon preservation by comparing the oxygenated and anoxic depositional environments. Through comparisons of these results with modern sedimentary environments, and by use of a simple diagenetic model, we conclude that the enhanced carbon mineralization under oxygenated conditions in unit 1 of the Xiamaling Formation required a minimum of 4 to 8 % of present-day atmospheric levels (PAL) of oxygen. These oxygen levels are higher than estimates based on chromium isotopes and reinforce the idea that the environment contained enough oxygen for animals long before their evolution.

scholarly journals The Oxic Degradation of Sedimentary Organic Matter 1.4 Ga Constrains Atmospheric Oxygen Levels

2016 ◽  
Author(s):  
Shuichang Zhang ◽  
Xiaomei Wang ◽  
Huajian Wang ◽  
Emma U. Hammarlund ◽  
Jin Su ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Carbon Mineralization ◽  
Northern China ◽  
Black Shales ◽  
Depositional Environments ◽  
Iron Speciation ◽  
High Hydrogen ◽  
Oxygen Levels ◽  
Sedimentary Environments ◽  
High Concentrations

Abstract. We studied sediments from the ca. 1400 million-year-old Xiamaling Formation from the northern China Block. The upper unit of this formation (unit 1) deposited mostly below storm wave base and contains alternating black and green-gray shales with very different geochemical characteristics. The black shales are enriched in redox sensitive trace metals, have high concentrations of total organic carbon (TOC), high hydrogen index (HI) and iron speciation indicating deposition under anoxic, mostly euxinic, conditions. In contrast, the green-grey shales show no trace metal enrichments, low TOC, low HI and iron speciation consistent with an oxygenated depositional setting. Altogether, unit 1 displays alternations between oxic and anoxic depositional environments, and differences in carbon preservation consistent with observations from the modern ocean. We combined our TOC and HI index results to calculate the differences in carbon mineralization between the oxygenated and anoxic depositional environments. Through comparisons of these results with modern sedimentary environments, and by use of a simple diagenetic model, we conclude that carbon mineralization under oxygenated conditions at Xiamaling required a minimum of 4 % to 8 % of present-day oxygen levels (PAL). These oxygen levels are higher than estimates based on chromium isotopes and, furthermore, were likely sufficient for early animal respiration. Therefore, our results reinforce the idea that the environment contained enough oxygen for animals long before their evolution.

Depositional environments of limestones from the Taiyuan Formation in the North China Block interpreted from REE proxies

2020 ◽  
Vol 35 (2) ◽  
Author(s):  
Dawei Lv ◽  
Wengui Fan ◽  
John I. Ejembi ◽  
Dun Wu ◽  
Dongdong Wang ◽  
...  
Keyword(s):  
North China ◽  
Depositional Environments ◽  
North China Block ◽  
The North ◽  
Taiyuan Formation

scholarly journals Sufficient oxygen for animal respiration 1,400 million years ago

2016 ◽  
Vol 113 (7) ◽  
pp. 1731-1736 ◽  
Author(s):  
Shuichang Zhang ◽  
Xiaomei Wang ◽  
Huajian Wang ◽  
Christian J. Bjerrum ◽  
Emma U. Hammarlund ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Biological Evolution ◽  
Green Sulfur Bacteria ◽  
Time Interval ◽  
North China Block ◽  
Oxygen Levels ◽  
Sulfur Bacteria ◽  
Bottom Waters ◽  
Minimum Zone ◽  
Sufficient Oxygen

The Mesoproterozoic Eon [1,600–1,000 million years ago (Ma)] is emerging as a key interval in Earth history, with a unique geochemical history that might have influenced the course of biological evolution on Earth. Indeed, although this time interval is rather poorly understood, recent chromium isotope results suggest that atmospheric oxygen levels were <0.1% of present levels, sufficiently low to have inhibited the evolution of animal life. In contrast, using a different approach, we explore the distribution and enrichments of redox-sensitive trace metals in the 1,400 Ma sediments of Unit 3 of the Xiamaling Formation, North China Block. Patterns of trace metal enrichments reveal oxygenated bottom waters during deposition of the sediments, and biomarker results demonstrate the presence of green sulfur bacteria in the water column. Thus, we document an ancient oxygen minimum zone. We develop a simple, yet comprehensive, model of marine carbon−oxygen cycle dynamics to show that our geochemical results are consistent with atmospheric oxygen levels >4% of present-day levels. Therefore, in contrast to previous suggestions, we show that there was sufficient oxygen to fuel animal respiration long before the evolution of animals themselves.

scholarly journals Intensive volcanic eruptions recorded in black shales within the Xiamaling Formation in the North China Craton

2021 ◽  
Author(s):  
Shuan-Hong Zhang ◽  
Richard Ernst ◽  
Junling Pei ◽  
Sandra Kamo ◽  
Guohui Hu ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Volcanic Eruptions ◽  
Black Shales ◽  
The North ◽  
Xiamaling Formation

scholarly journals Molybdenum record from black shales indicates oscillating atmospheric oxygen levels in the early Paleoproterozoic

2018 ◽  
Vol 318 (3) ◽  
pp. 275-299 ◽  
Author(s):  
Dan Asael ◽  
Olivier Rouxel ◽  
Simon W. Poulton ◽  
Timothy W. Lyons ◽  
Andrey Bekker
Keyword(s):  
Atmospheric Oxygen ◽  
Black Shales ◽  
Oxygen Levels

Depositional environments and paleogeography in the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines formations, Alberta

1984 ◽  
Vol 21 (6) ◽  
pp. 698-714 ◽  
Author(s):  
David R. Taylor ◽  
Roger G. Walker
Keyword(s):  
Brackish Water ◽  
Late Jurassic ◽  
Major Change ◽  
Depositional Environments ◽  
Fluvial Deposits ◽  
Maximum Thickness ◽  
The North ◽  
Major Exception ◽  
Flow Directions ◽  
Sand Bodies

The marine Moosebar Formation (Albian) has a currently accepted southerly limit at Fall Creek (Ram River area). It consists of marine mudstones with some hummocky and swaley cross-stratified sandstones indicating a storm-dominated Moosebar (Clearwater) sea. We have traced a tongue of the Moosebar southward to the Elbow River area (150 km southeast of Fall Creek), where there is a brackish-water ostracod fauna. Paleoflow directions are essentially northwestward (vector mean 318°), roughly agreeing with turbidite sole marks (329°) in the Moosebar of northeastern British Columbia.The Moosebar sea transgressed southward over fluvial deposits of the Gladstone Formation. In the Gladstone, thick channel sands (4–8 m) are commonly multistorey (up to about 15 m), with well developed lateral accretion surfaces. The strike of the lateral accretion surfaces and the orientation of the walls of channels and scours indicate northwestward flow (various vector means in the range 307–339°). The Moosebar transgression was terminated by construction of the Beaver Mines floodplain, with thick, multistorey sand bodies up to about 35 m thick. Flow directions are variable, but various vector means roughly cluster in the north to northeast segment. This indicates a major change in dispersal direction from the Gladstone and Moosebar formations.A review of many Late Jurassic and Cretaceous units shows a dominant dispersal of sand parallel to regional strike. This flow is mostly north-northwestward (Passage beds, Cadomin, Gladstone, Moosebar, Gates, Chungo), with the southeasterly dispersal of the Cardium being the major exception. Only at times of maximum thickness of clastic input (Belly River and higher units, and possibly Kootenay but there are no published paleocurrent data) does the sediment disperse directly eastward or northeastward from the Cordillera toward the Plains.

Block tilting of the North Provence early Cretaceous carbonate margin: stratigraphic, sedimentologic and tectonic data

2009 ◽  
Vol 180 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Jean-Pierre Masse ◽  
Michel Villeneuve ◽  
Emmanuelle Leonforte ◽  
Jean Nizou
Keyword(s):  
Early Cretaceous ◽  
Biological Diversity ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Structural Elements ◽  
The North ◽  
Subaerial Exposure ◽  
Tectonic Events ◽  
Complete Series ◽  
Structural Architecture

Abstract In the western part of the Castellane tectonic arc, the so-called “ Provence platform area “, corresponding to the foreland of the Alpine nappes (figs. 1–2), is marked by Tithonian-Berriasian shallow water carbonates capped by hemipelagic sediments deposited from the Valanginian up to the Aptian-Albian. A detailed biostratigraphic study of the Berriasian succession, based on calcareous algae and foraminifera, allows us to distinguish a Lower to Middle Berriasian, with Clypeina sulcata, Clypeina isabellae and Holosporella sarda, from an Upper Berriasian with Pfenderina neocomiensis, Danubiella cernavodensis, Falsolikanella campanensis and Macroporella praturloni (fig. 3). We performed a field survey of 30 sites located from Quinson to the west, and Escragnolles to the east (figs. 4–5) including the study of measured stratigraphic sections and the collection of samples for biostratigraphic interpretations. These stratigraphic investigations show that below the Valanginian beds, the Berriasian platfom carbonate succession, is locally incomplete, i.e. Upper Berriasian beds are frequently absent. During the Early and Middle Berriasian, depositional environments are marked by a strong bathymetric instability, with frequent subaerial exposure events, and a significant marine restriction; by contrast, during the Late Berriasian, the overall biological diversity increases and water agitation as well, which means a significant marine opening towards the basin. The Upper Berriasian hiatus is consequently regarded as the result of a Berriasian/Valanginian and/or a lowermost Valanginian erosion (fig. 6). The spatial distribution of complete or truncated Berriasian successions identifies east-west bands, in each band truncated series are located northward and complete series are located southward. Bands are limited by thrust or strip faults interpreted as palaeofaults reactivated during the Alpine orogeny (fig. 7). These fault-bounded blocks, 3 to 10 km in width, known as the Aiguine, La Palud-sur-Verdon, Carajuan-Audibergue and Peyroulles-La Foux blocks, are southerly rotated by 1 to 2o. We regard this structural architecture as the result of basinward tilting of blocks. Due to their rotation, the uplifted parts were eroded whereas the depressed parts were protected against erosion (fig. 8). Such a dynamic behavior reflects a distensive tectonic regime, which has been active at least during the Valanginian, that is after the drowning of the North-Provence carbonate platform. These structural events are considered as the regional expression of the Neocimmerian tectonic phase coupled with an enhancement of the Atlantic rifting. The orientation of the major Alpine structural elements (folds and faults) of the Castellane arc, is mostly inherited from these early Cretaceous tectonic events.

scholarly journals A Mesoproterozoic iron formation

2018 ◽  
Vol 115 (17) ◽  
pp. E3895-E3904 ◽  
Author(s):  
Donald E. Canfield ◽  
Shuichang Zhang ◽  
Huajian Wang ◽  
Xiaomei Wang ◽  
Wenzhi Zhao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Time Window ◽  
Iron Formation ◽  
The North ◽  
Fe Oxidation ◽  
Organic Biomarkers ◽  
Rock Eval ◽  
Fe Reduction ◽  
Rule Out ◽  
Xiamaling Formation

We describe a 1,400 million-year old (Ma) iron formation (IF) from the Xiamaling Formation of the North China Craton. We estimate this IF to have contained at least 520 gigatons of authigenic Fe, comparable in size to many IFs of the Paleoproterozoic Era (2,500–1,600 Ma). Therefore, substantial IFs formed in the time window between 1,800 and 800 Ma, where they are generally believed to have been absent. The Xiamaling IF is of exceptionally low thermal maturity, allowing the preservation of organic biomarkers and an unprecedented view of iron-cycle dynamics during IF emplacement. We identify tetramethyl aryl isoprenoid (TMAI) biomarkers linked to anoxygenic photosynthetic bacteria and thus phototrophic Fe oxidation. Although we cannot rule out other pathways of Fe oxidation, iron and organic matter likely deposited to the sediment in a ratio similar to that expected for anoxygenic photosynthesis. Fe reduction was likely a dominant and efficient pathway of organic matter mineralization, as indicated by organic matter maturation by Rock Eval pyrolysis combined with carbon isotope analyses: Indeed, Fe reduction was seemingly as efficient as oxic respiration. Overall, this Mesoproterozoic-aged IF shows many similarities to Archean-aged (>2,500 Ma) banded IFs (BIFs), but with an exceptional state of preservation, allowing an unprecedented exploration of Fe-cycle dynamics in IF deposition.

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