【摘要】 丹霞山是"中国丹霞"世界自然遗产的典型代表,目前对成景地层-上白垩统丹霞组沉积环境的研究程度不高,尤其对丹霞组锦石岩段沉积环境还存在争议。文中利用沉积学和稳定同位素地球化学方法,对丹霞山丹霞组锦石岩段钙质泥岩进行研究,分析该套泥岩沉积时期的古环境和古气候。粤北丹霞盆地丹霞组锦石岩寺段钙质泥岩的δ¹³C_PDB值在-3.34‰～-2.0‰之间,平均值为-2.49‰,δ¹⁸O_PDB值在-8.9‰～-5.7‰之间,平均值为-7.28‰。盐度值Z平均为119,在中国典型湖相碳酸盐岩碳氧同位素分布图中,样品主要投点于四川盆地侏罗系大安寨段和青藏高原北部的湖相碳酸盐岩中,预示着其可能形成于咸水-半咸水的陆相湖泊体系中。其古水温为19～34℃,平均为26℃之间。在75Ma,丹霞盆地大气CO₂浓度为1009～1436ppmv,平均为1282ppmv。丹霞盆地晚白垩世锦石岩寺段时期,具有干燥的地表沉积环境,可能与晚白垩世中期Campanian期东亚中纬度地区的干旱古气候条件相关。更多还原

【Abstract】 Danxiashan is a typical representative of the world’s natural heritage-"China Danxia". The study on the sedimentary environment of the Upper Cretaceous Danxia formation is not deep, especially for Jinshiyansi section of Danxia formation. In this research, the calcareous mudstone in Jinshiyan section of Danxia formation was studied by means of sedimentology and stable isotope geochemistry. The value of δ¹³C_PDB of the calcareous mudstone in the Jinshiyansi section is between-3.34‰ and-2.0‰, with an average value of -2.49‰; the value of δ¹⁸O_PDB is between-8.9‰ and -5.7‰, with an average value of -7.28‰. The salinity value Z is 119 on average. In the carbon and oxygen isotope distribution map of typical lacustrine carbonate rocks in China, the samples are mainly taken in the range of the lacustrine carbonate rocks in the Jurassic Daanzhai section in Sichuan basin and the northern part of Qinghai-tibet plateau, indicating that they developed in the saltwater or semi-saltwater lake system. The ancient water temperature is between 19 and 34℃, with an average of 26℃. At 75 Ma, the atmospheric concentration of CO₂ in Danxia basin was 1009～1436 ppmv, with an average of 1282 ppmv. In the Jinshiyansi period of the late Cretaceous, Danxia basin had a dry surface sedimentary environment which may be related to the arid paleoclimate conditions in the middle latitude region of East Asia in Campanian period.更多还原