Orbital cycle records in shallow unconsolidated sediments: implications for global carbon cycle and hydrate system evolution in deep-sea area sediments of the Qiongdongnan Basin

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 11

Published: Jan. 17, 2025

Introduction Milankovitch theory has extensive application in sequence stratigraphy and the establishment of time scales. However, it is rarely applied to shallow strata rich hydrates. Cyclostratigraphic analysis Quaternary unconsolidated sediments can help identify climate sea level changes that correspond orbital cycles improve our understanding dynamic evolution Methods Using natural gamma-ray log data from deepwater area well W01 Qiongdongnan Basin, cycle was conducted primary astronomical period W01. Anchored existing AMS-14 C age bivalve shell as reference point, an scale established. Simultaneously, through analyses major trace elements total organic carbon content (TOC) sediment samples, how influenced past environmental conditions. Furthermore, employing sedimentary noise models, relative change reconstructed. Results Sedimentary 27.34 m 6.73 were identified GR W01, corresponding periods 405 kyr 100 eccentricity, with a duration approximately 2.5 Myr. The spectral paleoenvironmental proxies reveals 27 m, while model reconstructs fluctuating rise change. An obliquity modulation 170 TOC data, which may reflect combined effects other parameters. Discussion Spectral indicators showed long eccentricity had varying degrees influence on paleoclimate, paleosalinity, paleoredox Additionally, 1.2 Myr significant factor influencing during early Pleistocene South China Sea (SCS). In addition, confirmed dominant glacial-interglacial SCS 0.6 Ma present period. Synthesize above analysis, phases low amplitude or minimum value cycle, are associated lower temperature, conditions become more conducive hydrate accumulation.

Language: Английский

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Effect of Pressure on the Diversity and Potential Activity of Aerobic Methanotrophs in Marine Sediments: A Case Study From the Shenhu Area, Northern South China Sea

Journal of Geophysical Research Oceans, Journal Year: 2025, Volume and Issue: 130(2)

Published: Feb. 1, 2025

Abstract High hydrostatic pressure in deep‐sea environments potentially impacts microbial community diversity, the structure of cellular components and functions. The specific characteristics aerobic methanotrophs originating from their responses to local fluctuations terms diversity methane oxidation potential remain unexplored. This study investigates subsurface sediments rich natural gas hydrate‐bearing region Shenhu area, Northern South China Sea. By conducting (AeOM) incubation experiments under various environmental pressures up 10 MPa, aims elucidate differences AeOM rates. results show a profound impact on both taxonomic composition bacterial methanotrophic communities capacity for consumption. key methanotrophs, that is, Methylococcales, exhibit gradual decrease as rises. Accordingly, rates also significant negative correlation with ( r = 0.986, P < 0.01). three dominant genera, unclassified_Methylococcaceae , Methylobacter Methylocaldum exhibited irregular varying conditions, lowest abundance observed at 2 MPa. Our shows is primary methanotroph exhibits main response changes marine environments.

Language: Английский

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Lacustrine hydrochemical variations and carbon sequestration under hyperthermal climates: insights from the Lower Eocene Kongdian Formation (Bohai Bay Basin, NE China)

International Journal of Earth Sciences, Journal Year: 2025, Volume and Issue: unknown

Published: March 22, 2025

Language: Английский

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Organic matter accumulation and carbon sequestration in the Paleocene-Eocene Thermal Maximum: Insights from the Kongdian Formation in Cangdong Sag, Bohai Bay Basin

Journal of Asian Earth Sciences, Journal Year: 2025, Volume and Issue: unknown, P. 106606 - 106606

Published: April 1, 2025

Language: Английский

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The formation of tubular seep carbonate deciphered from mineralogical and geochemical characteristics: an example from the South China Sea

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Aug. 26, 2024

As a special type of seep carbonate, the many details concerning formation mode and mechanism tubular carbonates are rarely reported. Here, new geochemical mineralogical data regarding carbonate (SQW-65) Sample SQW-65 had anomalously negative δ 13 C values positive 18 O values, which suggested dissociation gas hydrate. Additionally, almost all sub-samples showed no Ce anomaly (Ce/Ce * average = 0.93), with obvious U enrichment (21.3&lt; EF &lt;240.3), indicates that studied was formed in an anoxic environment. Subsequently, process is further discussed according to variability characteristics from rim core formation. In early stage (periphery), owing influence terrigenous components, quartz Ti content Y/Ho ratio were high. However, periphery, components gradually weakened. addition, core, carbon oxygen isotope “covariation” coupling relationship, U, reduction total rare earth element content. This because as outer wall thickens internal fluid channel narrows, intensity sulphate-driven anaerobic oxidation methane associated precipitation rate also increase.

Language: Английский

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Organic carbon oxidation and the associated pyrite formation in deep sediments at the Nankai subduction zone

Marine and Petroleum Geology, Journal Year: 2024, Volume and Issue: 169, P. 107081 - 107081

Published: Aug. 30, 2024

Language: Английский

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Petroleum evolution and its genetic relationship with the associated Jinding Pb Zn deposit in Lanping Basin, Southwest China

International Journal of Coal Geology, Journal Year: 2024, Volume and Issue: 294, P. 104620 - 104620

Published: Oct. 16, 2024

Language: Английский

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Proven and Potential Microbial Contributions to the Gulong Shale Oil

Journal of Earth Science, Journal Year: 2024, Volume and Issue: 35(6), P. 2149 - 2153

Published: Dec. 1, 2024

Language: Английский

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