Zircon LA-ICP-MS Dating of the Volcanic Rocks from Huaining Basin in the Middle——Lower Yangtze Valley
详细信息
- 责任者：Yan Jun (School of Resources and Environmental Engineering ; Hefei University of Technology ; Hefei 230009 ; China) ; Shi Lei
- 刊名：Geological Review
- 出版年：2013
- 卷期：59(6)
- 关键词：火山岩 ; volcanic rocks ; 铀—铅计时 ; U-Pb dating ; 长江中下游成矿带 ; Metallogenic Belt of Middle and Lower Reaches of Yangtze River
- 页码：p.1218-1226
- 图表：6 illus., 3 tables, 26 refs.
- 分类号：0801
- issnNo：ISSN0371-5736
- isbnNo：CN11-1952/P
摘要
The Huaining basin is one of the many Mesozoic volcanic basins in the Middle—Lower Yangtze Valley,where from the bottom to up the volcanic rocks of the Pengjiakou and the Jiangzhen Formations distributed.The rock types are dominantly trachyte tufflava,trachyandesite and rhyolite. SiO2contents of samples from the Pengjiakou Formation are 61. 56% and 70. 61%,respectively and that from the Jiangzhen Formation are from 61.91% to 63. 77%. All the samples are shoshonite serials with the samples of the Pengjiakou Formation being more potassium enrichment. Zircon LA-ICPMS U-Pb isotopic dating on the volcanic rocks from the Pengjiakou and Jiangzhen Formations gives weighted mean206Pb /235U ages of 130. 0 ± 1. 7 Ma( MSWD = 0. 73) and 130. 5 ± 1. 7Ma( MSWD = 0. 78),respectively,which indicates they erupted in the Early Cretaceous within a briefly active duration. The ages of volcanic rocks in the Huaining basin are consistent with that of other basins distributed in the Middle—Lower Yangtze Valley,suggesting that erupted ages of the Mesozoic volcanic rocks in the Middle—Lower Yangtze Valley concentrated in a period of 135 to 127 Ma and the volcanic rocks were derived from partial melting of lithospheric mantle under a intense extended setting.