Thermal evolution of the southeastern Canadian Cordillera
Thermal evolution of the southeastern Canadian Cordillera
复制标题
加拿大东南部科迪勒拉山脉的热演化
DOI：
10.1139/e95-130
复制
发表时间：
1995
影响因子：
1.4
通讯作者：
R. Parrish
中科院分区：
文献类型：
--
作者：
R. Parrish
加拿大南部科迪勒拉的东部变质顶端是一个复合核杂岩，在较低的构造层次上暴露出Monashee滑脱，这是一个主要的收缩断层，晚白垩世至古新世具有较大的东向位移。这条断层的上盘--塞尔柯克异形体，是一个剪切的逆冲片，记录了大约170-60 Ma期间的变质和变形事件，并在逐渐加深的水平上记录了更年轻的运动学和热事件。Monashee杂岩是Monashee滑脱岩系的下盘地体，由早元古代结晶基底杂岩组成，上面覆盖着晚元古代和显生界的变质沉积岩。根据本文提供的U-Pb数据，在古近纪(60-55 Ma)，莫纳什杂岩发生了显著的变质变形。对U-Pb钛铁矿资料的分析表明，该变质事件的持续时间最多只有几百万年，为进一步研究该变质事件的成因提供了强有力的地质依据。
The eastern metamorphic culmination of the southern Canadian Cordillera is a composite core complex, which at low structural levels exposes the Monashee decollement, a major contractional fault with large Late Cretaceous to Paleocene east-directed displacement. The hanging wall of this fault, the Selkirk allochthon, is a sheared thrust sheet, recording metamorphic and deformational events spanning the period from ca. 170 to 60 Ma, with younger kinematic and thermal events recorded at progressively deeper levels. The Monashee complex, the footwall terrane of the Monashee decollement, consists of an Early Proterozoic crystalline basement complex overlain by Late Proterozoic and perhaps Phanerozoic metasedimentary rocks. The Monashee complex was significantly metamorphosed and deformed in Paleogene time (60–55 Ma), on the basis of U–Pb data presented in this paper. Analysis of U–Pb titanite data show that the duration of this metamorphic event was but a few million years at most, and it provides a strong arg...