Organic and inorganic geochemical cyclicity of a Maastrichtian oceanic open-shelf carbonate source rock

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: April 10, 2025

Organic-rich source rocks are not only crucial for hydrocarbon exploration and production but also serve as valuable archives of past environmental conditions. This study investigates the Upper Cretaceous (Maastrichtian) present in Al-Lajoun basin central Jordan, to identify geochemical compositional variability corresponding paleo-environmental conditions during deposition. To this end, a multifaceted approach using Rock-Eval, SGR, XRD, XRF, ICP-OES, SEM-EDX, thin-section petrography is utilized understand bulk organic inorganic proxies. Based on results, Jordan rock characterized organic-rich, Type IIS kerogen, thermally immature rock, representing three distinct cycles matter distribution. Cycle 1 defined organic-rich carbonate mudstones with an average total carbon (TOC) content 17 wt.%. cycle represents high productivity, anoxic bottom water conditions, episodic detrital influx (clays quartz). 2 by silica-rich wackestones TOC 15 wt.%, reflecting shift from carbonate-dominated silica-dominated biota, likely driven increased nutrient supply changing climatic These resulted bioproductivity highly reducing anoxic/euxinic 3 foraminiferal packstones 12 relatively sediment input, comparatively low productivity The between identified implies over open shelf setting, which turn changes ocean currents impacting upwelling system Tethys margin. Understanding relationship currents, climate, composition efficiently exploring exploiting rocks. A regional correlation these their signatures could provide powerful tool trace associated climate change along margin Early Maastrichtian.

Language: Английский

FORAMINIFERAL CARBONATE PRODUCTION DECREASE IN A RAPIDLY CHANGING FJORD (HORNSUND, SVALBARD 2002–2019)

The Journal of Foraminiferal Research, Journal Year: 2025, Volume and Issue: 55(2), P. 144 - 159

Published: April 1, 2025

ABSTRACT Fjords are critical carbon burial hotspots, playing a significant role in climate regulation. However, the impact of current change on foraminifera Arctic fjords remains underexplored, despite foraminiferal inorganic carbon’s substantial contribution to glaciomarine sediments form calcium carbonate. This study investigates how benthic assemblages high-latitude fjord responded recent climatic shifts terms abundance and species composition between 2002 2019. The environmental changes have reduced number tests produced by foraminifera, shifted towards smaller species, increased agglutinated specimens sediments. These factors contributed an over tenfold decline carbonate 2019 compared those from 2002, providing evidence change’s at this location.

Language: Английский

Stability of Reactive Iron‐Bound Organic Carbon During Sulfidization of Iron Oxides: Insights From Methane‐Seep Sediments

Geophysical Research Letters, Journal Year: 2025, Volume and Issue: 52(8)

Published: April 21, 2025

Abstract The association of organic carbon (OC) to reactive iron oxides (Fe R ), forming OC‐Fe complexes, represents a significant OC sink in marine sediments. However, the impact diagenetic processes, such as sulfate reduction and sulfide formation, on stability sediments remains poorly understood. Here, we compare sulfidic from three cores taken at methane seeps with non‐sulfidic sediment record nearby site. Our results show that an overall 6.3% decrease is associated 42% Fe during transformation sulfides, suggesting resistant sulfidization. We observed highly 13 C‐depleted sediments, likely due interaction between anaerobic oxidation methane. findings highlight natural offering new insights into role continental margin

Language: Английский