Journal article
Preliminary Estimation of Paleoproductivity via TOC and Habitat Types: Which Method Is More Reliable? - A Case Study on the Ordovician-Silurian Transitional Black Shales of the Upper Yangtze Platform, South China
Journal of China University of Geosciences, Vol.19(5), pp.534-548
10/01/2008
DOI: 10.1016/S1002-0705(08)60059-X
Abstract
New total organic carbon (TOC) data from the two Ordovician-Silurian transitional graptolite-bearing black shale intervals, the Wufeng Formation and the Longmaxi Formation in Central Guizhou and West Hubei, respectively, as well as previously reported TOC data from the same intervals in other places on the Yangtze platform of South China, have been used to produce an initial estimate of the primary paleoproductivity via a conventional inverse method (i.e., Rpp-inverse). The values of the Rpp-inverse are estimated to be 32 (43-21) gC/(m(2).a) (Wufeng Formation) and 21 (27-16) gC/(m(2).a) (Longmaxi Formation). Also, simultaneously, the habitat types (i.e., HT; cf., BA: benthic assemblage) and their temporal and spatial changes have been documented from the same succession, and an initial estimate of the primary paleoproductivity has been produced using a forward method (i.e., Rpp-forward). Being bounded mainly by the peritidal to inner-shelf environment shelly-facies or mixed-facies successions with BA1 to BA3 faunas both at the top and the base, which indicates the habitat types from HT II1 to HT III2, the biohabitat type of the two graptolite-bearing black shale intervals can be limited to HT Ill to HT IV, corresponding to the inner shelf to the outer shelf, with depths from roughly 60 m to 200-300 m. Based on the current data from the South China Sea and the southern part of the East China Sea, values of Rpp-forward should be about 100 to 400 gC/(m(2).a). The difference in the results via the two methods suggests that paleoproductivity estimates from the geological strata need to be made cautiously, with particular attention paid to the paleogeographic setting, oxic-anoxic conditions, as also the preservation factor of organic carbon.
Details
- Title: Subtitle
- Preliminary Estimation of Paleoproductivity via TOC and Habitat Types: Which Method Is More Reliable? - A Case Study on the Ordovician-Silurian Transitional Black Shales of the Upper Yangtze Platform, South China
- Creators
- Su Wenbo - China University of Geosciences (Beijing)Wang Yongbiao - China University of GeosciencesBradley D Cramer - University of Iowa, Earth and Environmental SciencesAxel Munnecke - Univ Erlangen Nurnberg, GeoZentrum Nordbayern, Fachgrp Palaoumwelt, D-91054 Erlangen, GermanyLi Zhiming - China University of GeosciencesFu Lipu - Chinese Academy of Geological Sciences
- Resource Type
- Journal article
- Publication Details
- Journal of China University of Geosciences, Vol.19(5), pp.534-548
- Publisher
- CHINA UNIV GEOSCIENCES
- DOI
- 10.1016/S1002-0705(08)60059-X
- ISSN
- 1002-0705
- Number of pages
- 15
- Grant note
- G0800-06-ZS-319 / SINOPEC 40372057; 40772076 / National Natural Science Foundation of China
- Language
- English
- Date published
- 10/01/2008
- Academic Unit
- Earth and Environmental Sciences; Office Of The Provost; International Programs
- Record Identifier
- 9984229171202771
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