RT Journal Article
T1 Organic matter influence on ooid formation: New insights into classic examples (Great Salt Lake, USA; Triassic Germanic Basin, Germany)
A1 Pei, Yu
A1 Suárez González, Pablo
A1 Duda, Jan-Peter
A1 Reitner, Joachim
AB Ooids are coated grains composed of a tangential or radial cortex growing around a nucleus. They are common in carbonate deposits of almost any geological age and provide insights into environmental conditions. However, abiotic or biotic factors influencing their formation remain unclear. This study aims to advance current understanding of ooid formation with a multi-analytical approach (for example, field emission scanning electron microscopy, Raman spectroscopy and micro X-ray fluorescence) to classic examples from Great Salt Lake, USA, and the Lower Triassic Germanic Buntsandstein Basin, Germany. Both of these deposits represent hypersaline shallow-water environments where ooids are closely associated with microbial mats. Great Salt Lake ooids are dominantly 0.2 to 1.0 mm in size, ellipsoidal to subspherical in shape, composed of aragonite and contain organic matter. Germanic Buntsandstein Basin ooids are mainly ≤4 mm in size, spherical to subspherical in shape, composed of calcite and currently contain little organic matter. Despite the differences, both ooids have the same cortex structures, likely reflecting similar formation processes. Some Great Salt Lake ooids formed around detrital grains while others exhibit micritic particles in their nuclei. In Germanic Basin ooids, detrital nuclei are rare, despite the abundance of siliciclastic particles of various sizes in the host rocks. Germanic Basin deposits also include ‘compound ooids’, i.e. adjacent ooids that coalesced with one another during growth, suggesting static in situ development, which is supported by the lack of detrital grains as nuclei. Germanic Basin ooids also grew into laminated microbial crusts with identical microstructures, further indicating a static formation. Such microbial crusts typically form through mineral precipitation associated with organic matter (for example, extracellular polymeric substances), suggesting a similar formation pathway for ooids. The inferred key-role of organic matter is further supported by features in radial ooids from the Great Salt Lake, which commonly exhibit, from their nuclei towards their surface, increasing organic matter contents and decreasing calcification.
PB Wiley
YR 2024
FD 2024-02-07
LK https://hdl.handle.net/20.500.14352/108040
UL https://hdl.handle.net/20.500.14352/108040
LA eng
NO Pei, Yu, et al. «Organic Matter Influence on Ooid Formation: New Insights into Classic Examples (Great Salt Lake, USA ; Triassic Germanic Basin, Germany)». Sedimentology, vol. 71, n.o 5, agosto de 2024, pp. 1419-35, https://doi.org/10.1111/sed.13179
NO Göttingen Academy of Sciences and Humanities
NO Ministerio de Ciencia e Innovación
NO China Scholarship Council
NO University of Tübingen
NO China Postdoctoral Science Foundation
NO Alexander von Humboldt Foundation
DS Docta Complutense
RD 10 abr 2025