scholarly journals In situ U-Pb dating and geochemical characterization of multi-stage dolomite cementation in the Ediacaran Dengying Formation, Central Sichuan Basin, China: Constraints on diagenetic, hydrothermal and paleo-oil filling events

2022 ◽  
Vol 368 ◽  
pp. 106481
Author(s):  
Ao Su ◽  
Honghan Chen ◽  
Yue-xing Feng ◽  
Jian-xin Zhao ◽  
Zecheng Wang ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Geochemical Characterization ◽  
Multi Stage ◽  
Dengying Formation ◽  
Central Sichuan Basin

Hydrothermal dolomite reservoir in the Precambrian Dengying Formation of central Sichuan Basin, Southwestern China

2017 ◽  
Vol 82 ◽  
pp. 206-219 ◽  
Author(s):  
Mingyou Feng ◽  
Pengcheng Wu ◽  
Zitong Qiang ◽  
Xiaohong Liu ◽  
Yong Duan ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Southwestern China ◽  
Dengying Formation ◽  
Central Sichuan Basin ◽  
Hydrothermal Dolomite

scholarly journals In Situ Geochemical Analysis of Organics in Growth Lines of Antarctic Scallop Shells: Implications for Sclerochronology

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 529 ◽  
Author(s):  
Alberto Pérez-Huerta ◽  
Sally E. Walker ◽  
Chiara Cappelli
Keyword(s):  
Shell Growth ◽  
Organic Matrix ◽  
Atom Probe ◽  
Proxy Data ◽  
Geochemical Characterization ◽  
Growth Increments ◽  
Scallop Shells ◽  
The Antarctic

Bivalve shells are extensively used as bioarchives for paleoclimate and paleoenvironmental reconstructions. Proxy calibrations in recent shells are the basis for sclerochronology and the applications of geochemistry data to fossils. Shell geochemical information, however, could be altered with the disappearance of intercrystalline organic matrix components, including those linked to shell growth increments, during early diagenesis. Thus, an evaluation of the chemistry of such organics is needed for the correct use of sclerochronological records in fossil shells. Here, we use atom probe tomography (APT) for in situ geochemical characterization of the insoluble organic matrix in shell growth increments in the Antarctic scallop, Adamussium colbecki. We confirm the presence of carboxylated S-rich proteoglycans, possibly involved in calcite nucleation and growth in these scallops, with significant concentrations of magnesium and calcium. Diagenetic modification of these organic components could impact proxy data based on Mg/Ca ratios, but more importantly the use of the δ15N proxy, since most of the shell nitrogen is likely bound to the amide groups of proteins. Overall, our findings reinforce the idea that shell organics need to be accounted for in the understanding of geochemical proxies.

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