|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|6431419||1635153||2014||17 صفحه PDF||سفارش دهید||دانلود رایگان|
- The inferred tectonic setting by new discrimination diagrams are agreeing with the reported ones.
- The new discrimination diagrams are reliable in inferring the tectonic origin of all types of rocks.
- The new discrimination diagrams may be applied successfully for young, older and altered rocks.
Several new multi-dimensional tectonomagmatic discrimination diagrams employing log-ratio variables of chemical elements and probability based procedure have been developed during the last 10Â years for basic-ultrabasic, intermediate and acid igneous rocks. There are numerous studies on extensive evaluations of these newly developed diagrams which have indicated their successful application to know the original tectonic setting of younger and older as well as sea-water and hydrothermally altered volcanic rocks. In the present study, these diagrams were applied to Precambrian rocks of Mexico (southern and north-eastern) and Argentina. The study indicated the original tectonic setting of Precambrian rocks from the Oaxaca Complex of southern Mexico as follows: (1) dominant rift (within-plate) setting for rocks of 1117-988Â Ma age; (2) dominant rift and less-dominant arc setting for rocks of 1157-1130Â Ma age; and (3) a combined tectonic setting of collision and rift for Etla Granitoid Pluton (917Â Ma age). The diagrams have indicated the original tectonic setting of the Precambrian rocks from the north-eastern Mexico as: (1) a dominant arc tectonic setting for the rocks of 988Â Ma age; and (2) an arc and collision setting for the rocks of 1200-1157Â Ma age. Similarly, the diagrams have indicated the dominant original tectonic setting for the Precambrian rocks from Argentina as: (1) with-in plate (continental rift-ocean island) and continental rift (CR) setting for the rocks of 800Â Ma and 845Â Ma age, respectively; and (2) an arc setting for the rocks of 1174-1169Â Ma and of 1212-1188Â Ma age. The inferred tectonic setting for these Precambrian rocks are, in general, in accordance to the tectonic setting reported in the literature, though there are some inconsistence inference of tectonic settings by some of the diagrams. The present study confirms the importance of these newly developed discriminant-function based diagrams in inferring the original tectonic setting of Precambrian rocks.
Journal: Journal of South American Earth Sciences - Volume 56, December 2014, Pages 468-484