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Preservation of Cyanobacterial UVR‐Shielding Pigment Scytonemin in Carbonate Ooids Formed in Pleistocene Salt Lakes in the Qaidam Basin, Tibetan Plateau
Author(s) -
Sun Yu,
Li Yiliang,
Li Long,
He Hongping
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083321
Subject(s) - geology , aragonite , ooid , halite , gypsum , evaporite , geochemistry , carbonate , sedimentary depositional environment , paleontology , structural basin , sedimentary rock , calcite , materials science , metallurgy
The formation of ooids and their use as a proxy to trace biogeochemical cycles have long been controversial. Here, we examined three beds of evaporite‐cemented ooids in the Qaidam Basin, including a layer of dolomitic ooids formed at 293 ± 4 kyr and cemented by gypsum at 266 ± 3 kyr, a layer of aragonitic ooids formed at 163 ± 1 kyr and cemented by halite at 111 ± 0.8 kyr, and another layer of aragonitic ooids formed at 38 ± 0.5 kyr and cemented by gypsum at 23 ± 0.3 kyr. The Raman spectra of organic extracts from these ooids indicate ubiquitous preservation of scytonemin, a unique cyanobacterial ultraviolet radiation (UVR)‐shielding pigment. This discovery suggests that ooids are capable of preserving biomarker from their depositional environment. Consequently, ooid may be used as a proxy for tracing biogeochemical processes and potentially applied to the search for life on Mars.