South Extremity of Andes: Geology of Isla de los Estados, Argentine Tierra del Fuego
South Extremity of Andes: Geology of Isla de los Estados, Argentine Tierra del Fuego
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安第斯山脉南端：阿根廷火地岛 Isla de los Estados 的地质
DOI：
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发表时间：
1974
期刊：
影响因子：
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通讯作者：
R. Casanova
中科院分区：
文献类型：
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作者：
I. W. D. Dalziel;R. Caminos;K. Palmer;F. Nullo;R. Casanova
最近对阿根廷火地岛上安第斯山脉科迪勒拉山脉东南部的一项研究证实，该岛完全由上侏罗统-下白垩统火山和沉积沉积组成。岛上大部分地区都露出了一层非常厚的硅质火山岩，由均匀的凝灰岩和次要的火山沸石和熔岩组成。这些岩石由石英-辉石到流纹岩组成，沉积在以浅海为主、零星分布火山岛的地区。上覆沉积岩为黑色钙质泥岩，出露在岛的西北部。这两个地层之间的边界是一种整合的过渡性沉积接触。对详细构造资料的初步分析表明，岩石分布在单一的大型向斜中，东端不对称，向北倾覆，西端竖直。从安第斯科迪勒拉到北斯科舍海脊的整个岛屿的岩性和结构的连续性再次强调了这些地质特征进入斯科舍弧区的持久性。
A recent study of the southeastern extremity of the Andean Cordillera on Isla de los Estados in Argentina Tierra del Fuego confirmed that the island consists exclusively of Upper Jurassic-Lower Cretaceous volcanic and sedimentary deposits. A very thick sequence of silicic volcanic rocks consisting of homogeneous tuffs and subordinate ignimbrites and lavas crops out over most of the island. These rocks, of quartz-latite to rhyolite composition, were deposited in a dominantly shallow-marine area with sporadic volcanic islands. The overlying sedimentary rocks are black calcareous mudstones cropping out in the northwest of the island. The boundary between the two formations is a concordant, transitional sedimentary contact. Preliminary analysis of detailed structural data ind cates that the rocks are disposed in a single large syncline, asymmetric and overturned to the north at the east end of the island, and upright in the west. Continuity of lithology and structure through the island from the Andean Cordillera toward the North Scotia Ridge reemphasizes the persistence of these geologic features into the Scotia arc.