کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10120766 1640466 2018 27 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Magmatism: A crustal and geodynamic perspective
ترجمه فارسی عنوان
ماگماتیسم: چشم انداز پوسته و ژئودینامیک
کلمات کلیدی
پانگها ابرقهرمان، گرم کردن مانت، کمربند ارتوپسی دور کمر، گرماسنج مگا، چرخه های جهانی، آمار زمین شناسی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی
The Earth's continental crust constitutes a major interface between the inner and outer envelops of the planet, controlling the differentiation of magmas produced in the mantle and their transfer to the surface. This close link facilitates the use of different chemical proxies to qualitatively unravel the crustal thickness related to fossil magmatic systems based on the message carried by magmas. This paper aims to bridge different results of statistical petrology, recently obtained at different scales of observation, in a global geodynamic model. Statistical analyses applied to a large multidimensional database of magmatic rocks show that crustal thickness could actually exert a first-order control on the composition of magmas, which become more calc-alkaline and comparatively less tholeiitic with increasing crustal thickness. Using this correlation, we document the progressive build-up of a thick (>40 km) Jurassic to Cretaceous accretionary belt along the Circum-Pacific Orogenic Belts (CPOB) that bounded the Panthalassa Ocean. The destruction of this thick belt started at ca. 125 Ma and was initially recorded by the thinnest magmatic systems hosting amphibole-bearing magma. Thinning of the CPOB became widespread in the northern regions of western America and in the western Pacific after ca. 75 Ma, possibly in response to oceanic plate segmentation, which triggered slab rollback and overriding plate extension. This chemical evolution is superimposed on a more global evolution of magma controlled by the temperature of the mantle that has gradually decreased since 200 Ma. Although the relative contribution of crust vs mantle cooling in the chemical signature of magmatic rocks should be further explored in the future, our results offer a new global perspective of the magmatic history of Pangea, the last supercontinent.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 114, September 2018, Pages 329-335
نویسندگان
, ,