High authigenic Co enrichment in the non‐euxinic buff‐grey and black shale of the Chandarpur Group, Chhattisgarh Supergroup: implication for the late Mesoproterozoic shallow marine redox condition

Fifteen surface samples were examined to analyze palynology of the Permo-Triassic sediments of West Timor. The studied samples were collected from the clastic sediment of Bisane Formation which is considered to be the oldest formation. It derives from the Australian continent (Gondwana) following thecollision with the Banda volcanic arc. The Bisane Formation generally comprises thick calcareous sandstone (0.3-5 meters) with shale alternation and abundant marine microfossil of Chrinoid. The appearance of Chrinoid may indicate Permian age and shallow marine environment. Meanwhile, other Bisane sediment shows different lithology in which it is composed of the intercalation of non-calacreous, dark gray to black shale and siltstone showing papery structure and rich in sulphur. Generally, palynological assemblage of the studied samples characterises Permo-Triassic age as indicated by the existence of common striate-bisaccate pollen including Protohaploxypinus samoilovichii, P. fuscus, P. goraiensis, Striatopodocarpidites phaleratus, Pinuspollenites globosaccus and Lunatisporites pellucidus. However, the appearance of trilete-monosaccate spores of Plicatipollenites malabarensis and Cannanoropollis janakii within the non-calcareous shale samples de􀂿 nes the age as Permian or older for these samples. Interestingly, marine dino􀃀 agellates appear to mark calcareous samples suggesting the in􀃀 uence of a marine environment. They disappear from the non-calcareous samples indicating a freshwater environment. By integrating this palynological analysis and Permian tectonic event which is marked by rifting, it can be interpreted that the non-calcareous samples were formed during early syn-rift as evidenced by the occurrence of freshwater deposit (may be lacustrine). Subsequently, following sea level rises during post rift, the depositional environment shifted to shallow marine as indicated by the existence of calcareous Permo-Triassic samples. If this is the case, the appearance of Permo-Triassic sediments provides an opportunity to 􀂿 nd a new petroleum system in the Paleozoic series of West Timor. Source rock is represented by black shale, whereas reservoir is represented by thick sandstone.

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Depositional model for shallow-marine manganese deposits around black shale basins

Economic Geology ◽

10.2113/gsecongeo.83.1.93 ◽

1988 ◽

Vol 83 (1) ◽

pp. 93-117 ◽

Cited By ~ 115

Author(s):

Eric R. Force ◽

William F. Cannon

Keyword(s):

Black Shale ◽

Depositional Model ◽

Shallow Marine ◽

Manganese Deposits

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Multielement Imaging Reveals the Diagenetic Features and Varied Water Redox Conditions of a Lacustrine Dolomite Nodule

Geofluids ◽

10.1155/2022/9019061 ◽

2022 ◽

Vol 2022 ◽

pp. 1-20

Author(s):

Yuke Liu ◽

Wenyuan He ◽

Jinyou Zhang ◽

Zhenwu Liu ◽

Fazi Chen ◽

...

Keyword(s):

Spatial Resolution ◽

Black Shale ◽

Single Point ◽

Songliao Basin ◽

Redox Condition ◽

Aqueous Environment ◽

Imaging Data ◽

Imaging Results ◽

Laminated Structures

The genesis of dolostone has long been puzzling for more than two centuries. Although much work has been done on investigating the process of dolomitization, little emphasis has been put on examining the diagenetic water redox condition with the wealthy geochemical information preserved in primary dolomite, which is believed to archive the aqueous environment as well as biotic and/or abiotic effects during formation. In situ interpretation with high resolution is a prerequisite in refined research of dolomite. Here, we reported the multielement imaging results of a lacustrine dolomite nodule with the host black shale from the Songliao Basin, northeast of China. Micro X-ray fluorescence (μ-XRF) with a spatial resolution down to 10 μm was used for in situ scanning. Two key parameter settings of the μ-XRF, including single-point exposure time and spatial resolution, were optimized to achieve a better result in a reasonable scanning time scale. The final imaging data graphically revealed dynamic variation of elemental distributions, including elements enriched in dolomite (e.g., Ca, Mg, Fe, and Mn), clastic quartz (Si), and clay minerals (e.g., Al and K) and redox-sensitive trace elements (e.g., Cr, Mo, V, and U). The well-preserved laminated structures inside the nodule and the features with a magnesium-rich core wrapped with an iron-concentric outer layer and a manganese-concentric shell together indicated its primary form as dolomite and a gradual transformation into ankerite as well as manganese-ankerite. The elemental variation indicates a varied bottom water redox condition, which involved from sulfidic to ferruginous and manganous zones. Here, we propose that the intermittent supplies of sulfate and Fe-/Mn-oxidized minerals interrupting the black shale deposition while favoring dolomitization might be brought by the oxidized and salted seawater. And this lacustrine dolomite is expected to be a potential fingerprint mineral in tracking the seawater intrusions to the Songliao Basin which happened 91 million years ago.

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Biostratigraphy and paleoecology of the Lower Cretaceous sediments in the Outer Western Carpathians (Silesian Unit, Czech Republic)

Geologica Carpathica ◽

10.2478/v10096-011-0024-9 ◽

2011 ◽

Vol 62 (4) ◽

pp. 309-332 ◽

Cited By ~ 3

Author(s):

Marcela Svobodová ◽

Lilian Švábenická ◽

Petr Skupien ◽

Lenka Hradecká

Keyword(s):

Czech Republic ◽

Black Shale ◽

Lower Cretaceous ◽

Western Carpathians ◽

Calcareous Nannofossils ◽

Dinoflagellate Cysts ◽

Significant Component ◽

Continuous Section ◽

Shallow Marine ◽

Outer Western Carpathians

Biostratigraphy and paleoecology of the Lower Cretaceous sediments in the Outer Western Carpathians (Silesian Unit, Czech Republic)Almost black shale filling fissures in the Štramberk Limestone belonging to the Silesian Unit, Outer Western Carpathians contain prolific and poorly to moderately well preserved spores, pollen, organic-walled dinoflagellate cysts, foraminifers, and calcareous nannofossils. A detailed micropaleontological analysis of the proved stratigraphical interval from the Valanginian to the Albian indicated sedimentary conditions of brackish, restricted marine, shallow-marine and neritic sedimentation. Moreover, it drew attention to occasional influence from the Boreal province in the depositional area of the NW part of Tethys, especially during the Early Valanginian and Hauterivian, as supported by the presence of highlatitude nannofossils and organic-walled dinoflagellate cysts. Terrestrial miospores form a significant component of palynoassemblages and give evidence of continent proximity in the Valanginian-Barremian interval. Samples were acquired from isolated fissure fills in the Štramberk Limestone and, therefore, they do not represent a continuous section.

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The expression of the Hangenberg Event (latest Devonian) in a relatively shallow-marine succession (Pomeranian Basin, Poland): the results of a multi-proxy investigation

Geological Magazine ◽

10.1017/s001675681400034x ◽

2014 ◽

Vol 152 (3) ◽

pp. 400-428 ◽

Cited By ~ 9

Author(s):

HANNA MATYJA ◽

KATARZYNA SOBIEŃ ◽

LESZEK MARYNOWSKI ◽

MARZENA STEMPIEŃ-SAŁEK ◽

KRZYSZTOF MAŁKOWSKI

Keyword(s):

Magnetic Susceptibility ◽

High Resolution ◽

Sea Level ◽

Black Shale ◽

Sea Level Changes ◽

European Standard ◽

Shallow Marine ◽

Environmental Perturbations ◽

Sedimentary Succession ◽

Reference Section

AbstractThe uppermost Famennian – lowermost Tournaisian interval has been analysed in detail using biostratigraphy, sedimentology, magnetic susceptibility and geochemistry in a reference section of the relatively shallow carbonate ramp environment within the Pomeranian Basin. High-resolution biostratigraphic study, based on miospores, allows recognition of the standard western Europeanlepidophyta–nitidus(LN) andverrucosus–incohatus(VI) zones, as well as theConvolutispora majorZone, a local Pomeranian equivalent of the European standardhibernicus–distinctus(HD) Zone. The sedimentary succession and specific phenomena recognized close to the Devonian/Carboniferous boundary, such as fluctuations in water column euxinia, wildfire evidence, relative sea-level changes and perturbations of the carbon cycle reflected by positive carbon excursions, display a pattern partly similar to that observed in many areas in Europe during the Hangenberg Event, although the Hangenberg Black Shale horizon is not developed here. These important microscale environmental perturbations were observed not only within the Famennian LN miospore Zone but in a wide interval between the LN and the lowermost localConvolutispora majormiospore zones ( = lower part of HD standard miospore Zone). It is still uncertain whether the recognized event(s) were connected solely with the Hangenberg Event, which was possibly complex and multi-phased as is sometimes suggested, or whether they represent a succession of regionally limited, post-Hangenberg events. This question needs to be further investigated on broader stratigraphic and geographical scales.

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