TY - JOUR
T1 - Shallow stratification prevailed for ~1700 to ~1300 Ma ocean
T2 - Evidence from organic carbon isotopes in the North China Craton
AU - Luo, Genming
AU - Junium, Christopher K.
AU - Kump, Lee R.
AU - Huang, Junhua
AU - Li, Chao
AU - Feng, Qinglai
AU - Shi, Xiaoying
AU - Bai, Xiao
AU - Xie, Shucheng
N1 - Funding Information:
The authors would like to thank many students in CUG for their assistance in the field. Prof. Yuansheng Du in CUG was thanked here for his interpretation on the sedimentary environments of the Gaoyuzhuang Formation. We are indebted to Prof. Hongfu Yin in CUG for his comments on the manuscript and Prof. Jean Lynch-Stieglitz for editorial handing. Drs. Linda Kah, Andrey Bekker, Timothy Lyons and Noah Planavsky are thanked for their constructive comments which improved the quality of this paper greatly. We appreciate Dr. Linda Kah for her information about the paleoredox condition of the Zigazino–Komorovo Formation in southern Ural Mountains, Russia. This work was supported by the 973 program (grant No. 2011CB808800 , 2013CB955704 ), the NSFC (grant No. 41002003 ), the MOE of China (grant No. NCET-11-0724 to C.L.), the 111 project (grant No. B08030 ) and the fundamental research funds for the central universities, China University of Geosciences, Wuhan ( CUG130406 and CUG120117 ) and by an award from the NASA Astrobiology Institute to LRK.
PY - 2014/8/15
Y1 - 2014/8/15
N2 - The Late Paleoproterozoic to Early Mesoproterozoic (from ~1700 Ma to ~1300 Ma) was highlighted by the assembly of the Nuna supercontinent, expansion of euxinic marine environments and apparent stasis in the diversity of eukaryotes. The isotopic composition of carbonate carbon (δ13Ccarb) was surprisingly constant during this interval, but little is known about the secular variation in the organic carbon isotopic composition (δ13Corg). Here we report δ13Corg data from the latest Paleoproterozoic (>1650 Ma) to Early Mesoproterozoic (~1300 Ma) succession in North China. The δ13Corg values range from -25‰ to -34‰, and are dependent on sedimentary facies. In subtidal and deeper environments δ13Corg values are low and constant, ca. -32‰, but relatively enriched and more variable in shallower intertidal and supratidal environments. We attribute the facies-dependent variation in δ13Corg to the presence of a shallow chemocline. A probable result of a shallow chemocline is that it supported significant contributions of organic matter produced by chemoautotrophic and/or anaerobic photoautotrophic microbes in relatively deep environments from the latest Paleoproterozoic to Early Mesoproterozoic continental shelf of North China.
AB - The Late Paleoproterozoic to Early Mesoproterozoic (from ~1700 Ma to ~1300 Ma) was highlighted by the assembly of the Nuna supercontinent, expansion of euxinic marine environments and apparent stasis in the diversity of eukaryotes. The isotopic composition of carbonate carbon (δ13Ccarb) was surprisingly constant during this interval, but little is known about the secular variation in the organic carbon isotopic composition (δ13Corg). Here we report δ13Corg data from the latest Paleoproterozoic (>1650 Ma) to Early Mesoproterozoic (~1300 Ma) succession in North China. The δ13Corg values range from -25‰ to -34‰, and are dependent on sedimentary facies. In subtidal and deeper environments δ13Corg values are low and constant, ca. -32‰, but relatively enriched and more variable in shallower intertidal and supratidal environments. We attribute the facies-dependent variation in δ13Corg to the presence of a shallow chemocline. A probable result of a shallow chemocline is that it supported significant contributions of organic matter produced by chemoautotrophic and/or anaerobic photoautotrophic microbes in relatively deep environments from the latest Paleoproterozoic to Early Mesoproterozoic continental shelf of North China.
KW - Carbon isotopic composition
KW - Mesoproterozoic
KW - North China Craton
KW - Paleoproterozoic
KW - Stratified sea
UR - http://www.scopus.com/inward/record.url?scp=84902154969&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84902154969&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2014.05.020
DO - 10.1016/j.epsl.2014.05.020
M3 - Article
AN - SCOPUS:84902154969
SN - 0012-821X
VL - 400
SP - 219
EP - 232
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -