| 山东蓬莱史家沟西山火山碎屑岩风化壳元素地球化学特征 |
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| 关键词:weathering crust geochemistry volcaniclastic rock climate Penglai |
| 基金项目:中国地质调查局项目“华北地区重要地质遗迹调查(山东)”(编号: DD2017078);“山东省重要地质遗迹调查”(编号: 鲁财建指[2012]110号) |
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| The Geochemical Characteristics of the Weathering Crust Originating from Volcaniclastic Rock in Xishan of Shijiagou, Penglai,Shandong Province |
| A total of 21 samples were collected in the weathering crust originating from volcaniclastic rock in Xishan of Penglai, Shandong Province, and were analyzed for major elements, trace elements, rare earth elements and clay minerals. The geochemical characteristics were revealed, and the age and the climate of crust formation were discussed. The weathering crust in Xishan originated from basic-ultrabasic vitric tuff with the average CIA of 92.3, and suffered from strong weathering. Most of K, Na, Ca and Mg were lost, and Al, Fe accumulation and desilicification were clearly found. The profile of Xishan could be divided into two eruptive cycles with the boundary at 200 cm. The first eruptive cycle is the horizon below 200 cm, and the horizon above 200 cm is the second eruptive cycle. The CIA of the first cycle ranges from 94.0 to 97.2, indicating that the first cycle is at the strong weathering level. The first cycle exhibits significant leaching of V, Rb, Sb, Mo, Li and Ga, and has the peak of ?REE, ?HREE, and ?LREE at 213 cm with the negative anomaly of Ce. The first cycle suffered from strong montmorillonitization, and shows gray and white color. The CIA of the second cycle varies between 86.3 and 89.2, lower than that of the first cycle; nevertheless, there exist some primary minerals, such as feldspar, hematite and quartz. It could be inferred that the weathering crust of Xishan occurred in Late Miocene and Pliocene with warm and humid climate, and the cooling trend resulted in the significant differences of weathering degree and geochemical characteristics between two eruptive cycles. |
| BIAN Yue-yue,MENG Yong-hui,YAN Tang,YAO Ying-qiang,LIU Rui-feng,ZOU Lian-qing,SHANG Ting-ting,FU Juan.2018.The Geochemical Characteristics of the Weathering Crust Originating from Volcaniclastic Rock in Xishan of Shijiagou, Penglai,Shandong Province[J].Acta Geoscientica Sinica,39(4):498-512. |
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