Climatic and environmental indications of carbon and oxygen isotopes from the Lower Cretaceous calcrete and lacustrine carbonates in Southeast and Northwest China
Climatic and environmental indications of carbon and oxygen isotopes from the Lower Cretaceous calcrete and lacustrine carbonates in Southeast and Northwest China
复制标题
中国东南西北地区下白垩统钙质结垢和湖相碳酸盐岩碳氧同位素气候与环境指示
DOI：
10.1016/j.palaeo.2013.03.011
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发表时间：
2013-09-01
影响因子：
3
通讯作者：
Liu, Ling
中科院分区：
文献类型：
--
作者：
Li, Xianghui;Xu, Wenli;Liu, Ling
碳和氧同位素比是根据来自中国东南部 (SE) 和西北 (NW) 四个碳酸盐岩相的 100 个下白垩统样品测定的，用于古气候和古环境分析。这些样品被解释为远端冲积池（SF1）、开放浅湖（SF2）、滨海湖泊（SF3）和沼泽（SF4）岩相下的沉积物。分析结果显示，在中国东南部地区，Delta C-13 值范围在 -5.0 ppm 至 3.0 ppm 之间，随时间推移呈负趋势，Delta O-18 值均为负值（-19.3 ppm - 7.4 ppm）；在中国西北地区，Delta C-13 值范围为 -4.0 ppm 至 4.0 ppm，具有周期性变化，Delta O-18 值范围为 -18.0 ppm 至 1.5 ppm。 大多数 Delta C-13 和 Delta O-18 的值相对较大且协方差明显，表明中国西北部和东南部地区半干旱气候和封闭性咸水湖泊、沼泽和池塘的主导地位早白垩纪时期。其中，正的 C-13 三角洲（0.0 ppm 至 4.0 ppm）和相对较重的 Delta O-18（-5.0 ppm 至 1.5 ppm）值表明，闽西南早特里阶、酒泉盆地西部中阿普阶、鄂尔多斯盆地西南部阿普阶晚期、以及鄂尔多斯盆地西南阿普阶晚期-早阿尔阶阶间歇性干旱蒸发中断。六盘山盆地。在早阿普特阶的短暂时期内，浙江西南部局部地区高岭石含量较高，气候炎热湿润，而酒泉盆地西部地区植物区系温暖，可能是一个例外。其中，极端负三角洲O-18值（主要为-19.0~-9.0 ppm）表明闽东南贝里亚-巴列姆阶、六盘山盆地晚阿普阶、鄂尔多斯盆地西南部阿普阶中晚、酒泉盆地西部中晚阿普阶气温相对较低，推测与海拔2 500 m~4 500 m有关。三角洲C-13和三角洲O-18在中国西北地区比中国东南部和中国大陆比美国有更多的正值和更多的协方差比，表明前者比后者处于干旱气候，这可能与距海距离的古地理有关。早白垩世钙质结垢三角洲C-13值偏移的初步对比表明，海洋OAE与陆地碳酸盐沉积物之间以及中国西北与美洲之间具有良好的兼容性。大陆，意味着全球对海洋和陆地环境中的碳循环做出反应。该特征表明了前新生代陆地钙质结垢三角洲 C-13 偏移的全球相关性和应用的潜力。 (C) 2013 Elsevier B.V. 保留所有权利。
Carbon and oxygen isotopic ratios were determined from similar to 100 Lower Cretaceous samples from four carbonate-bearing facies in Southeast (SE) and Northwest (NW) China for palaeoclimatic and palaeoenvironmental analyses. The samples were interpreted as sediments within sublithofacies of distal alluvial ponds (SF1), open shallow lakes (SF2), littoral lakes (SF3), and marshes (SF4). Results of analyses show in SE China, delta C-13 values range between -5.0 parts per thousand and 3.0 parts per thousand with a negative trend through time, and delta O-18 values are all negative (-19.3 parts per thousand--7.4 parts per thousand); in NW China, delta C-13 values range from -4.0 parts per thousand to 4.0 parts per thousand with periodic change, and delta O-18 values range between -18.0 parts per thousand and 1.5 parts per thousand.Both relatively heavy values and pronounced covariances of most delta C-13 and delta O-18 indicate semiarid climate and domination of closed brackish lakes, marshes, and ponds in NW and SE China during the Early Cretaceous. Of them, positive delta C-13 (0.0 parts per thousand to 4.0 parts per thousand) and relatively heavy delta O-18 (-5.0 parts per thousand to 1.5 parts per thousand) values suggest interruptions of arid-evaporation in intermittences of the early Hauterivian in SW Fujian, of the middle Aptian in West Jiuquan basin, of the late Aptian in SW Ordos basin, and of the late Aptian-early Albian in Liupanshan basin. In a short interval of the early Aptian, the hot and humid climate occurred in local SW Zhejiang by high kaolinite content and in West Jiuquan basin by warm flora could be an exception. Particularly, extremely negative delta O-18 values (mainly -19.0--9.0 parts per thousand) indicate relatively low temperature in SE Fujian in the Berriasian-Barremian, in Liupanshan basin in the late Aptian, in SW Ordos basin in the late Albian, and in West Jiuquan basin in the mid-late Aptian, which is supposed to attribute to the presence of 2500 m-4500 m in elevation. More positive values and more covariance ratios of delta C-13 and delta O-18 in NW China than in SE China and in mainland China than in America indicate a arider climate in former than in later, probably attributing to the palaeogeography in distance to sea.A tentative correlation of the Early Cretaceous delta C-13 value excursion of calcretes shows a good compatibility between marine OAEs and terrestrial carbonate sediments and between NW China and America continents, implying a global response to carbon cycle in both marine and terrestrial environments. The feature suggests the potential of global correlation and application of terrestrial calcrete delta C-13 excursions in pre-Cenozoic. (C) 2013 Elsevier B.V. All rights reserved.