Organomineralization in Mesoproterozoic giant ooids

Tang, Dongjie; Shi, Xiaoying; Shi, Qing; Wu, Jin‐Jian; Song, Gaoyuan; Jiang, Ganqing

doi:10.1016/j.jseaes.2015.04.034

Cited by 24 publications

(9 citation statements)

References 86 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This deduction is in good consistence with the frequent occurrence of seafloor precipitations (e.g. Tang et al 2015) and the overall less variable carbonate carbon isotopes during the Mesoproterozoic (Bartley and Kah 2004;Guo et al 2013). If this deduction is the case, many similar concretions formed in nitrate and Mn reduction zones with seawater-like carbon isotope composition should exist in the Mesoproterozoic strata and further studies are required to test this explanation.…”

Section: Palaeoenvironmental Implicationsmentioning

confidence: 63%

Growth mechanisms and environmental implications of carbonate concretions from the ~ 1.4 Ga Xiamaling Formation, North China

et al. 2019

View full text Add to dashboard Cite

Carbonate concretions provide unique records of ancient biogeochemical processes in marine sediments, and have the potential to reflect seawater chemistry indirectly. In fine-siliciclastic settings, they preferentially form in organicrich mudstones, owing to a significant fraction of the bicarbonate required for carbonate precipitation resulted from the decomposition of organic matter in sediments. In the Member IV of the Xiamaling Formation (ca. 1.40-1. 35 Ga), North China, however, carbonate concretions occur in organic-poor green silty shales (avg. TOC =~0.1 wt%). In order to elucidate the mechanism of the concretion formation and their environmental implications, a thorough study on the petrographic and geochemical compositions of the concretions and their host rocks was conducted. Macro-to microscopic fabrics, including deformed shale laminae surrounding the concretions, "cardhouse" structures of clay minerals and calcite geodes in the concretions, indicate that these concretions are of early diagenetic origin prior to the significant compaction of clay minerals. The carbon isotope compositions of the concretions (− 1.7‰ to + 1.5‰) are stable and close to or slightly lower than that of the contemporaneous seawater, indicating that the bicarbonates required for the concretion formation were mainly sourced from seawater by diffusion rather than produced by methanogenesis or anoxic oxidation of methane (AOM); the rare occurrence of authigenic pyrite grains in the concretions likely indicates that bacterial sulfate reduction (BSR) did not play a significant role in their formation either. Almost all the calcite in the concretions has low Mn-Fe in nuclei but high Mn-Fe in rims with average Mn/Fe ratio close to 3.3. The calcite shows positive Ce anomalies (avg. 1.43) and low Y/Ho ratios (avg. 31). This evidence suggests that Mn reduction is the dominant process responsible for the formation of calcite rims while nitrate reduction probably triggered the precipitation of calcite nuclei. Prominence of Mn reduction in the porewater likely indicates that there was sufficient oxygen to support active Mn-redox cycling in the overlying seawater.

show abstract

Section: Palaeoenvironmental Implicationsmentioning

confidence: 63%

Growth mechanisms and environmental implications of carbonate concretions from the ~ 1.4 Ga Xiamaling Formation, North China

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The ooidal intervals exhibited wavy and ripple lamination and the muddy intervals were bioclastic wackestone, which suggests open marine conditions with variable hydrodynamic conditions and high sediment supply (Flügel, ; Tucker & Wright, ). The abundant marine cementation within intergranular voids suggests that the ooidal‐muddy laminites preferably formed along the windward side of the reef‐shoal (Flügel, ; Li et al, ; Tang et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Giant ooids were commonly thought to form under high agitation conditions, low nuclei supply, and high seawater carbonate saturation (Sumner & Grotzinger, ). However, studies of Early Triassic giant ooids indicated that abnormally high‐energy (likely storms) and high‐CaCO 3 saturation controlled the formation of giant ooids (Lehrmann, Payne, & Pei, ; Li et al, ; Li, Yan, & Chen, ), and Tang et al () suggested that the main controls on the generation of the Wumishan giant ooids were high carbonate saturation and moderately agitated waters.…”

Section: Discussionmentioning

confidence: 99%

“…This result implies that the normal and giant ooids formed under highly carbonate-supersaturated environments. Some studies indicated that locally high CaCO 3 supersaturation could be caused by microbial groups and their metabolisms (Dupraz et al, 2009;Visscher & Stolz, 2005 supersaturation (Bartley & Kah, 2004;Tang et al, 2015). Incursion of deepwater that is rich in HCO 3 − , HS − , and CO 2 would create, at least locally, high CaCO 3 supersaturation conditions in shallow seawater (Dupraz et al, 2009;Visscher, Reid, & Bebout, 2000).…”

Section: Depositional Model For Normal and Giant Ooidsmentioning

confidence: 99%

See 1 more Smart Citation

Origin of ooids in ooidal‐muddy laminites: A case study of the lower Cambrian Qingxudong Formation in the Sichuan Basin, South China

et al. 2017

View full text Add to dashboard Cite

Ooids have been considered the most intriguing component of carbonate rocks, but the formation mechanism of carbonate ooids remains a matter of intense discussion. The lower Cambrian Qingxudong Formation in the southeastern Sichuan Basin contains abundant ooidal‐muddy laminites. Petrographic and sedimentological analyses revealed that these laminites formed in a shallow‐marine environment (preferably along the windward side of the reef‐shoal). Changing energy conditions caused variable supplies of grainy and muddy accumulation. A wide variety of ooids developed in grainy intervals. The normal ooids (<2 mm in diameter) in the lower portion of the laminites developed under high‐energy shallow‐water conditions, whereas the giant ooids (>2 mm in diameter) in the upper portion of the laminites developed in a deepening and moderate‐energy subtidal environment but were influenced by episodic hydrodynamic events. Petrographic and geochemical analyses suggest that microbes played an important role in ooid formation. High carbonate‐supersaturated and alkaline conditions that were mediated by microbial activity (e.g., bacterial sulfate reduction and photosynthesis) and agitated seawater conditions were the most important factors that mediated the formation of the Qingxudong ooids. This study provides new insights into paleooceanographic conditions during the Early Cambrian and offers a perspective on the formation of ancient normal and giant ooids.

show abstract

“…Regarding the formation of ooids, there are non-biological hypotheses, in which ooids get their spherical shape owing to highly agitated water [3], such as sea waves pounding on the beaches, that rolls the ooids into spherical shape. However, there is no highly agitated water in lakes.…”

Section: Were the Martian Ooids Formed By Microbes?mentioning

confidence: 99%

Putative Martian Microbes Formed Plentiful Ooids on Mars

Liu¹

2015

Astrobiol Outreach

View full text Add to dashboard Cite

NASA's Mars Rover Curiosity discovered plentiful indigenous spherical ooids at High Dune and Namib Dune in Bagnold dune field, Gale Crater, Mars. Closely resembling ooids of Earth, the Martian ooids are spherical in shape, similar in size, mostly about 0.5 mm in diameter. Colors of the Martian ooids are various, including white, yellow translucent, green, grey, and yellow. The Martian ooids should have been formed by microbes, because ooids of Earth have recently been found to be formed by microbes and microbial borings are found in ooids of Earth and Mars. The Martian ooids are unlikely to have been formed by non-biological mechanisms, because there was no highly agitated water at the discovery sites.

show abstract

Organomineralization in Mesoproterozoic giant ooids

Cited by 24 publications

References 86 publications

Growth mechanisms and environmental implications of carbonate concretions from the ~ 1.4 Ga Xiamaling Formation, North China

Growth mechanisms and environmental implications of carbonate concretions from the ~ 1.4 Ga Xiamaling Formation, North China

Origin of ooids in ooidal‐muddy laminites: A case study of the lower Cambrian Qingxudong Formation in the Sichuan Basin, South China

Putative Martian Microbes Formed Plentiful Ooids on Mars

Contact Info

Product

Resources

About