Carbonate isotope chemostratigraphy suggests revisions to the geological history of the West Finnmark Caledonides, northern Norway
Carbonate isotope chemostratigraphy suggests revisions to the geological history of the West Finnmark Caledonides, northern Norway
复制标题
碳酸盐同位素化学地层学建议对挪威北部西芬马克喀里多尼德斯地区的地质历史进行修正
DOI：
--
复制
发表时间：
2006
影响因子：
2.7
通讯作者：
A. Fallick
中科院分区：
文献类型：
--
作者：
T. Slagstad;V. Melezhik;C. Kirkland;K. B. Zwaan;D. Roberts;I. Gorokhov;A. Fallick
挪威北方西芬马克Sørøy序列（结构上Kalak推覆杂岩）Falkenes组角闪岩相大理岩的锶和碳同位素数据表明，这些大理岩沉积于760 ~ 710 Ma之间。类似年龄的大理石以前只在挪威中北部的Uppermost Allochthon被发现，在那里它们被认为具有劳伦的祖先。一个类似的起源和构造地层位置似乎可能为Falkenes组。相比之下，在Kalak推覆复合体的结构较低的单位似乎有波罗的海的亲和力。这种二分法要求人们对西芬马克加里东期构造地层学的普遍看法进行修正。结合最近从与大理石有关的岩石中获得的锆石和独居石的U-Pb测年结果，同位素数据表明，卡拉克推覆杂岩的Sørøy序列并不像以前认为的那样是一个连续的沉积序列，而是由一些不同的、可能不相关的逆冲岩片组成，这些逆冲岩片在晚志留世、斯堪的纳维亚造山作用期间聚集在一起。这项工作表明，西芬马克加里东山脉与斯堪的纳维亚加里东山脉的某些其他地区有着大致相似的构造变质历史，并有助于现有的数据，可能使整个加里东带的“化学地层”相关和重建。
Strontium and carbon isotopic data from amphibolite-facies marbles of the Falkenes formation, Sørøy succession (structurally upper Kalak Nappe Complex) in West Finnmark, northern Norway, indicate that the marbles were deposited between 760 and 710 Ma. Marbles of similar age have previously been identified only in the Uppermost Allochthon in north–central Norway, where they are considered to have a Laurentian ancestry. A similar origin and tectonostratigraphic position appears likely for the Falkenes formation. In contrast, structurally lower units within the Kalak Nappe Complex appear to have Baltican affinities. This dichotomy requires that commonly held ideas regarding the tectonostratigraphy of the West Finnmark Caledonides be revised. Combined with recent U–Pb dating of zircon and monazite from rocks associated with the marbles, the isotopic data suggest that the Sørøy succession of the Kalak Nappe Complex is not a continuous, depositional sequence as previously thought, but rather consists of a number of disparate and probably unrelated thrust-sheets, assembled during Late Silurian, Scandian orogenesis. This work shows that the West Finnmark Caledonides share a generally similar tectonometamorphic history with certain other parts of the Scandinavian Caledonides, and contributes to already existing data that may allow ‘chemostratigraphic’ correlation and reconstruction of the entire Caledonian belt.