کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8907368 | 1634675 | 2018 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Continental margin subsidence from shallow mantle convection: Example from West Africa
ترجمه فارسی عنوان
فروپاشی حاشیه قاره ای از جنس مگس کم عمق: مثال از غرب آفریقا
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
کنسانتره گوشته کوچک در مقیاس کوچک، کیپ ورد، غرب آفریقا، حمایت پویا بالا بردن، فروپاشی،
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی
Spatial and temporal evolution of the uppermost convecting mantle plays an important role in determining histories of magmatism, uplift, subsidence, erosion and deposition of sedimentary rock. Tomographic studies and mantle flow models suggest that changes in lithospheric thickness can focus convection and destabilize plates. Geologic observations that constrain the processes responsible for onset and evolution of shallow mantle convection are sparse. We integrate seismic, well, gravity, magmatic and tomographic information to determine the history of Neogene-Recent (<23 Ma) upper mantle convection from the Cape Verde swell to West Africa. Residual ocean-age depths of +2 km and oceanic heat flow anomalies of +16 ± 4 mWâmâ2 are centered on Cape Verde. Residual depths decrease eastward to zero at the fringe of the Mauritania basin. Backstripped wells and mapped seismic data show that 0.4-0.8 km of water-loaded subsidence occurred in a â¼500 à 500 km region centered on the Mauritania basin during the last 23 Ma. Conversion of shear wave velocities into temperature and simple isostatic calculations indicate that asthenospheric temperatures determine bathymetry from Cape Verde to West Africa. Calculated average excess temperatures beneath Cape Verde are >+100â°C providing â¼103 m of support. Beneath the Mauritania basin average excess temperatures are <â100â°C drawing down the lithosphere by â¼102 to 103 m. Up- and downwelling mantle has generated a bathymetric gradient of â¼1/300 at a wavelength of â¼103 km during the last â¼23 Ma. Our results suggest that asthenospheric flow away from upwelling mantle can generate downwelling beneath continental margins.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 481, 1 January 2018, Pages 350-361
Journal: Earth and Planetary Science Letters - Volume 481, 1 January 2018, Pages 350-361
نویسندگان
Bhavik Harish Lodhia, Gareth G. Roberts, Alastair J. Fraser, Stewart Fishwick, Saskia Goes, Jerry Jarvis,