کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10121375 | 1641620 | 2005 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermal structure of the Costa Rica - Nicaragua subduction zone
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
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چکیده انگلیسی
We constructed four high-resolution, finite-element thermal models across the Nicaragua - Costa Rica subduction zone to predict the (i) thermal structure, (ii) metamorphic pressure (P)-temperature (T) paths followed by subducting lithosphere, and (iii) loci and types of slab dehydration reactions. These new models incorporate a temperature- and stress-dependent olivine rheology for the mantle-wedge that focuses hot asthenosphere into the tip of the mantle-wedge. At P = 3 GPa (100 km depth), predicted slab interface temperatures are â¼800 °C, about 170 °C warmer than temperatures predicted using an isoviscous mantle-wedge rheology. At the same pressure, predicted temperatures at the base of 7 km thick subducting oceanic crust range from 500 °C beneath SE Costa Rica to 400-440 °C beneath Nicaragua and NW Costa Rica. The high thermal gradients perpendicular to the slab interface permit partial melting of subducting sediments while the underlying oceanic crust dehydrates, consistent with recent geochemical studies of arc basalts. Hydrous eclogite is predicted to persist to â¼120 km depth beneath Nicaragua. This is slightly less than the â¼150 km depth extent of a dipping low-seismic-velocity wave guide which may reflect deeper persistence of metastable gabbro. Along-strike variations in the calculated thermal structure are relatively minor compared to variations in the distribution of Wadati-Benioff earthquakes and arc geochemistry, suggesting that regional variations in slab stresses, crustal thickness, incoming sediment load, and the distribution of hydrous minerals in the incoming lithosphere play important roles.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 149, Issues 1â2, 15 March 2005, Pages 187-200
Journal: Physics of the Earth and Planetary Interiors - Volume 149, Issues 1â2, 15 March 2005, Pages 187-200
نویسندگان
Simon M. Peacock, Peter E. van Keken, Stephen D. Holloway, Bradley R. Hacker, Geoffrey A. Abers, Robin L. Fergason,