GUADALUPIAN-LOPINGIAN BOUNDARY
; NORTHERN GUIZHOU PROVINCE
; ZHENGAN-DAOZHEN AREA
; LA-ICP-MS
; WESTERN GUANGXI
; KARSTIC BAUXITE
; SEA-LEVEL
; GLACIAL DEPOSITS
; MINERALOGICAL CHARACTERISTICS
; PALEOMAGNETIC CONSTRAINTS
WOS学科分类:
Geosciences, Multidisciplinary
WOS研究方向:
Geology
英文摘要:
The late Paleozoic Era was an interval of major tectonic and climatic changes, including formation of the supercontinent Pangea and the similar to 60-Myr-long Late Paleozoic Ice Age (LPIA). Although bauxite formation declined globally from the Carboniferous to the Permian in conjunction with global cooling, it was an interval of widespread bauxite formation in China. In South China, (1) the Jiujialu Formation bauxite deposits in central and northern Guizhou (Zunyi area) are of early-middle Visean age; (2) the Dazhuyaun Formation bauxite deposits in northern Guizhou (Wuchuan-Zhenean-Daozheng area) to southern Chongqing (Nanchuan area) and southeastern Guizhou (Fuquan-Kaili area) are of Late Pennsylvanian-Early Permian age; and (3) the Heshan Formation bauxite deposits in western Guangxi to Yunnan are of Middle-Late Permian age. In North China, the Benxi Formation bauxite deposits are of Late Mississippian-Middle Pennsylvanian age. The contrasting trends in bauxite metallogenesis between China and the rest of the world imply different climatic patterns in the eastern Tethys (high annual humidity with seasonal dryness) and Pangea (aridification). This hypothesis is further supported by differences in the chemical index of alteration, or CIA ( > 80 in the eastern Tethys vs.-50 in western Pangea), and in paleotemperatures (mean annual temperature, or MAT =-20 C in the eastern Tethys vs.-4 C in western Pangea) determined from Permo-Carboniferous siliciclastic deposits. Permo-Carboniferous bauxite deposits in South China formed in coastal plain and coastal karstic depression environments, in which the position of the groundwater table was related to sea-level changes. During the late Paleozoic, high-frequency eustatic fluctuations caused by waxing and waning of Gondwana icesheets controlled sedimentation in these coastal depositional systems, leading to cyclic accumulation of coal and bauxite deposits and cycles of vadoseand phreatic-type bauxite formation. The results of the present study show that, during interglacial stages, lateritization resulted from high pCO2, high sea-level and groundwater-table elevations, low precipitation, and limited vegetation cover, whereas during glacial stages, bauxitization of these ferralitic weathering products was promoted by low pCO2, low sea-level and groundwater-table elevations, high precipitation, and more extensive vegetation cover. Thus, a unique combination of geographic, climatic, and eustatic factors accounted for widespread formation of bauxite in South China during the LPIA.
1.China Univ Geosci, Sch Earth Sci, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Hubei, Peoples R China 2.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Hubei, Peoples R China 3.Univ Cincinnati, Dept Geol, Cincinnati, OH 45221 USA 4.Guizhou Bur Geol & Mineral Explorat & Dev, 106 Geol Party, Zunyi 563099, Peoples R China
Recommended Citation:
Yu, Wenchao,Algeo, Thomas J.,Yan, Jiaxin,et al. Climatic and hydrologic controls on upper Paleozoic bauxite deposits in South China[J]. EARTH-SCIENCE REVIEWS,2019-01-01,189:159-176