Glauconite authigenesis during the onset of the Paleocene-Eocene Thermal Maximum: A case study from the Khuiala Formation in Jaisalmer Basin, India

Choudhury, Tathagata Roy; Banerjee, Santanu; Khanolkar, Sonal; Saraswati, Pratul Kumar; Meena, Sher Singh

doi:10.1016/j.palaeo.2021.110388

Cited by 28 publications

(36 citation statements)

References 112 publications

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“…Glauconite is an iron-potassium hydrous phyllosilicate that is considered to be of diagenetic origin (Odin and Matter, 1980;López-Quirós et al, 2020). Various factors have been put forward to account for glauconite formation: reduced sedimentation rates, protracted availability of (dissolved) cations, oxygen-depleted, mildly reducing, conditions for the main ones (Odin and Matter, 1981;Amorosi, 1995;El Albani et al, 2005;Meunier and El Albani, 2007;Banerjee et al, 2016aBanerjee et al, , 2016bHuggett, 2021;Roy Choudhury et al, 2021). In addition, glauconite is often present in the form of pellets or lobate grains, showing frequent surface cracks (Boyer et al, 1977;Bayliss and Syvitski, 1982;Amorosi and Centineo, 2000;Adriaens et al, 2014;Velde, 2014).…”

Section: Glauconitementioning

confidence: 99%

Syndepositional glauconite as a paleoenvironmental proxy - the lower Cenomanian Chalk of Cap Blanc Nez (N-France)

et al. 2021

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At Cap Blanc Nez (Channel coast, France), the chalk of the Lower Cenomanian is very rich in glauconite. Glauconite is of authigenic origin and requires the mobilization of chemical elements for its growth: Si, Fe and K. If we already know thanks to elementary geochemistry (Ge/Si ratio) that the silica of the flint present in the chalk originates from the dissolution of sponges, is it the same for glauconite? This question only makes sense if glauconite is proved to be autochthonous and synsedimentary, and not reworked during the Cenomanian transgression. In addition, we wanted to know whether the study of the content of trace elements in glauconite could provide information on the conditions of authigenesis in glauconious chalk.The clay content of the chalk from the Lower Cenomanian has been examined and the green minerals were extracted from the rock to study their morphology, mineralogy, geochemistry (major & trace elements ) and grain size. The chalk consists of calcium carbonate, smectite and true glauconite, in the form of pellets, sometimes with rare traces of quartz and some centimeter-scale phosphate gravel. The grain-size distribution of the glauconites varies from one sample to another and is always poorly sorted, which militates in favor of an autochthonous (not reworked) origin of these minerals. This origin is also suggested by the virtual absence of terrigenous minerals, except for smectite known for its potential for wide distribution in the marine environment. The geochemistry of the samples shows a very homogeneous composition of major and trace elements, with a K2O content greater than 8%. This characterizes these glauconites as being very evolved, which indicates a long authigenic formation time (> 100 ky) and therefore an extremely reduced or irregular sedimentation rate. Here, glauconites are very rich in germanium, which makes it impossible to identify a source of silica (unlike what is possible with flints). It cannot therefore be said that the silica results from the dissolution of sponges but this enrichment in Ge, coupled with that in vanadium and the absence of enrichment in molybdenum, indicates a slightly reducing deposition milieu (suboxic). Such conditions usually favor organic matter accumulation, but not here, due to protracted sedimentation hiatuses. Lastly, glauconite trapped relatively large amounts of Ge due to reducing conditions and long exposure time to seawater, which makes it Revised manuscript with no changes marked Click here to view linked References

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Section: Glauconitementioning

confidence: 99%

Syndepositional glauconite as a paleoenvironmental proxy - the lower Cenomanian Chalk of Cap Blanc Nez (N-France)

et al. 2021

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“…2c and the insert). These features are indicative of 'highly evolved' glauconite (Baldermann et al, 2015;Choudhury et al, 2021).…”

Section: Resultsmentioning

confidence: 99%

Impact of green clay authigenesis on K–Mg–Fe sequestration in marine settings

Baldermann

Banerjee

Czuppon

et al. 2021

Preprint

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Retrograde clay mineral reactions (i.e., reverse weathering), including glauconite formation, are first-order controls on element (re)cycling vs sequestration in modern and ancient marine sediments. Here, we report substantial K–Mg–Fe sequestration by glauconite formation in shallow marine settings from the Triassic to the Holocene, averaging 4 ± 3 mmol K·cm−²·kyr− 1, 4 ± 2 mmol Mg·cm−²·kyr− 1 and 10 ± 6 mmol Fe·cm−²·kyr− 1, which is ~ 2 orders of magnitude higher compared to deep-sea settings. Upscaling of glauconite abundances in shallow-water (< 200 m) environments predicts a global K–Mg–Fe uptake of ~ 0.05–0.06 Tmol K·yr− 1, ~ 0.04–0.06 Tmol Mg·yr− 1 and ~ 0.11–0.14 Tmol Fe·yr− 1. We conclude that authigenic clay elemental uptake had a large impact on the global marine K, Mg and Fe cycles throughout Earth`s history, in particular during ‘greenhouse’ periods with sea level highstand. Quantifying authigenic clay formation is key for better understanding past and present geochemical cycling in marine sediments.

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“…The first indication of the autochthonous origin of glaucony is the relatively low thickness (less than 3 m) of the glauconite-bearing condensed interval, and the close association of the glauconitic pellets with trace fossils and intensely burrowed sediments [29,30]. Another reliable indication of authigenesis is the scarcity of small fragments of broken pellets and the presence of deeply penetrating cracks within the glauconitic granules, which in turn is indicative of little or no appreciable transport [31,32]. These fractures likely formed due to the expansional growth of glauconite, which induces cracking at the grain surface.…”

Section: Discussionmentioning

confidence: 99%

Mineralogical and Crystal-Chemical Constraints on the Glauconite-Forming Process in Neogene Sediments of the Lower Guadalquivir Basin (SW Spain)

Fernández-Landero

Fernández-Caliani

2021

Minerals

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Glaucony is a significant green marine facies in the northwestern passive margin of the Guadalquivir Basin (Spain), where glauconite formed authigenically on a sediment-starved continental shelf, with fecal pellets and benthic foraminiferal tests being the main glauconitized substrates. Results from a study using XRD, TGA-DSC, SEM-EDS, and EPMA have revealed that glauconite is remarkably heterogeneous in mineral composition and chemical maturity, even in a single grain, reflecting a complex interaction of micro-environmental factors, substrate influences and post-depositional alterations. In its early stage, the glauconitization process is consistent with the slow precipitation of a Fe-rich smectite phase, most likely intergrade between nontronite and Fe-montmorillonite end-members, which evolved to a regularly interstratified glauconite-smectite (Gl/S). The Fe-smectite-to-Gl/S transformation is interpreted as a diffusion-controlled reaction, involving sufficient Fe availability in pore water and the constant diffusive transport of seawater K+ and Mg2+ ions towards the substrate. The pelletal glauconite is actually a highly evolved Gl/S consisting almost totally of mica layers, with 0.74 ± 0.05 apfu of K+ in the interlayer, while the Gl/S occurring as replacements of foraminiferal tests contains a mean of 7% of expandable layers in the walls and 16% in the chamber fillings, due to rate-limited ion diffusion.

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Glauconite authigenesis during the onset of the Paleocene-Eocene Thermal Maximum: A case study from the Khuiala Formation in Jaisalmer Basin, India

Cited by 28 publications

References 112 publications

Syndepositional glauconite as a paleoenvironmental proxy - the lower Cenomanian Chalk of Cap Blanc Nez (N-France)

Syndepositional glauconite as a paleoenvironmental proxy - the lower Cenomanian Chalk of Cap Blanc Nez (N-France)

Impact of green clay authigenesis on K–Mg–Fe sequestration in marine settings

Mineralogical and Crystal-Chemical Constraints on the Glauconite-Forming Process in Neogene Sediments of the Lower Guadalquivir Basin (SW Spain)

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