你好,请
登录
首页
平台概况
新闻中心
中心新闻
行业新闻
媒体关注
平台资源
资源列表
平台服务
机时安排 A
机时安排 B
投诉建议
服务成效
服务成效
服务案例
下载中心
中心发布
调试工具
运行环境
关于
联系我们
发展历程
BJSHRIMP
平台组建背景
搜索
返回
Mississippian volcanism in the south-central Andes New U–Pb SHRIMP zircon geochronology and whole-rock geochemistry
[
查看
]
F.Martina
、
J.M.Viramonte
、
R.A.Astini
、
M.M.Pimentel
、
E.Dantas
In the northern extension of the Famatina and the southern Puna (NW Argentina) prominent rhyolitic volcanic rocks traditionally referred to as Ordovician are exposed, resting on metamorphic basement and covered by thick Late Paleozoic siliciclastic successions. We report new U–Pb SHRIMP ages from these rhyolites that show them to be of Mississippian (348–342 Ma) age, thus identifying a previously unknown volcanic event in this portion of western Gondwana. Whole-rock geochemistry and Sr–Nd isotopic analyses suggest a crustal source for these rocks but with a juvenile input (εNd(t) between −2.91 and −0.3, and TDM values between 1.09 and 1.1 Ga). This is different from the Early Paleozoic magmatism of western Argentina where crustal recycling took place without any involvement of mantle material. The Carboniferous magmatism is compatible with an extensional environment developed along the Terra Australis accretionary orogen as a result of tectonic switching processes. These rhyolites may be related to the coeval Mississippian A-type granites exposed to the east, in the Sierras Pampeanas, confirming the regional character of this magmatism.
© BJSHRIMP 2013 - bjshrimp.cn