The Mysterious Mid-Carnian “Wet Intermezzo” Global Event  

作　　者：James G.Ogg 

机构地区：[1]Department of Earth, Atmospheric and Planetary Sciences, Purdue University [2]Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences

出　　处：《Journal of Earth Science》2015年第2期181-191,共11页地球科学学刊（英文版）

基　　金：Support for this Mid-Carnian preparation wasprovided by a visiting professorship at the State Key Laboratory of Geobiology and Environmental Geology of the China University of Geosciences at Wuhan, China,and by a visiting-scholar sabbatical hosted by the Geosciences Australia in Canberra, Australia

摘　　要：Approximately 230 million years ago in the middle of the Carnian stage of the Upper Triassic, the sedimentary records in different regional basins display dramatic changes. Tropical carbonate platforms abruptly ended, and engorged river systems left widespread sand-rich layers across inland basins and coastal regions. This pulse lasted less than a million years in some basins, but constituted a permanent shift in others. Following this event, the Late Carnian has the earliest record of significant dinosaurs on land and the emergence of the calcareous nannoplankton in the oceans that now govern Earth＇s carbon cycle. This ＂most distinctive climate change within the Tri- assic＂ has been interpreted by some geoscientists as a global disruption of the Earth＇s land-ocean-biological system. The eruption of the Wrangellia large igneous province may have been the trigger for a sudden carbon-dioxide-induced warming and associated increased rainfall in some of these regions. Indeed, some workers have proposed that this ＂wet intermezzo＂ warming event is a useful analog to aid in predicting the effects of our future greenhouse on land ecosystems and ocean chemistry. However, the understanding of the onset, duration, global impacts and relatively rapid termination of this postulated warming pulse has been hindered by lack of a global dataset with inter-calibrated terrestrial and marine biostratigraphy, precise radio-isotopic ages, stable isotope records of temperature and the carbon system, and cycle-calibrated rates of regional and global change.Approximately 230 million years ago in the middle of the Carnian stage of the Upper Triassic, the sedimentary records in different regional basins display dramatic changes. Tropical carbonate platforms abruptly ended, and engorged river systems left widespread sand-rich layers across inland basins and coastal regions. This pulse lasted less than a million years in some basins, but constituted a permanent shift in others. Following this event, the Late Carnian has the earliest record of significant dinosaurs on land and the emergence of the calcareous nannoplankton in the oceans that now govern Earth＇s carbon cycle. This ＂most distinctive climate change within the Tri- assic＂ has been interpreted by some geoscientists as a global disruption of the Earth＇s land-ocean-biological system. The eruption of the Wrangellia large igneous province may have been the trigger for a sudden carbon-dioxide-induced warming and associated increased rainfall in some of these regions. Indeed, some workers have proposed that this ＂wet intermezzo＂ warming event is a useful analog to aid in predicting the effects of our future greenhouse on land ecosystems and ocean chemistry. However, the understanding of the onset, duration, global impacts and relatively rapid termination of this postulated warming pulse has been hindered by lack of a global dataset with inter-calibrated terrestrial and marine biostratigraphy, precise radio-isotopic ages, stable isotope records of temperature and the carbon system, and cycle-calibrated rates of regional and global change.

关 键 词：TRIASSIC CARNIAN climate pluvial Wrangellia carbon isotope EXCURSION DOLOMITE China LIP Yangtze Platform Wet Intermezzo large igneous province. 

分 类 号：P534.51[天文地球—古生物学与地层学]