Yan Kai, Wang Chun-Lian, Mischke Steffen, Wang Jiu-Yi, Shen Li-Jian, Yu Xiao-Can, Meng Ling-Yang
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, 100037, China.
Institute of Earth Sciences, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland.
Sci Rep. 2021 Jul 5;11(1):13846. doi: 10.1038/s41598-021-93125-8.
Major, trace and rare earth element (REE) geochemistry of the late Cretaceous lower Zhoutian Formation from the Jitai Basin of Southeast China were measured by inductively coupled plasma mass spectrometry (ICP-MS) analysis to infer the provenance of the sediments and to reconstruct the palaeoenvironment and palaeoclimate. The wide range of Sr/Cu ratios point to a fluctuating palaeoclimate, and the negative correlation between the FeO/MnO and AlO/MgO ratios and the Sr/Cu ratio indicates that the late Cretaceous climate during the lower Zhoutian Formation in the Jitai Basin can be divided into two parts. The lower part experienced two cooling periods, whilst the upper part was dominated by warm-humid climate. Mostly corresponding trends of the B/Ga, Sr/Ba and Sr/Cu ratios show that the salinity changed consistently with the late Cretaceous climate during the lower Zhoutian Formation in the Jitai Basin. During the lower part, the salinity changed from salt water to fresh/brackish water. In the upper part, water was mainly fresh/brackish, and there were many changes from fresh/brackish water to salt water. The relatively stable Ni/Co, V/Cr, V/(V + Ni) and Ce/Ce* data indicate a long period of oxic conditions. The La-Th-Sc, Th-Sc-Zr/10 and La/Th-Hf data of the silt- and sandstones of the lower Zhoutian Formation show that its provenance was mainly a mixture of felsic upper crust sediments and older sedimentary rocks.
通过电感耦合等离子体质谱（ICP-MS）分析，测定了中国东南部吉泰盆地晚白垩世周田组下段的主量、微量和稀土元素（REE）地球化学特征，以推断沉积物的物源，并重建古环境和古气候。广泛的Sr/Cu比值表明古气候波动，FeO/MnO和AlO/MgO比值与Sr/Cu比值之间的负相关表明，吉泰盆地周田组下段晚白垩世气候可分为两个部分。下部经历了两个降温期，而上部以温暖湿润气候为主。B/Ga、Sr/Ba和Sr/Cu比值的大多相应趋势表明，吉泰盆地周田组下段的盐度变化与晚白垩世气候一致。在下部，盐度从咸水变为淡水/微咸水。在上部，水主要是淡水/微咸水，且有多次从淡水/微咸水变为咸水的变化。相对稳定的Ni/Co、V/Cr、V/(V+Ni)和Ce/Ce*数据表明存在长期的氧化条件。周田组下段粉砂岩和砂岩的La-Th-Sc、Th-Sc-Zr/10和La/Th-Hf数据表明，其物源主要是长英质上地壳沉积物和较老沉积岩的混合物。
