کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4681987 1635140 2016 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The structure of the Amazonian craton: Available geophysical evidence
ترجمه فارسی عنوان
ساختار کاتون آمازون: شواهد ژئوفیزیک موجود
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی


• Geophysical data provide valuable results in the Amazonian craton.
• Deep structure of the craton allow crustal and lithospherical thickness estimations.
• Splitting analysis and seismic tomography enlight uncovered large areas.
• Areas with crustal thickening correspond to Paleoproterozoic magmatic arcs.
• New potential field database provide laterally continuous information in the region.

The Amazonian craton, which covers a large area of South America, and is thought to have been stable since the end of the Mesoproterozoic, has recently benefited from a series of regional geophysical surveys. The Amazonian craton comprises the northern Guyana shield and the southern Central Brazil shield. It has become the main subject of seismological studies aiming to determine crustal thickness. Moho thickness maps that cover a large part of the South American continent summarize these studies. Receiver function studies, aided by surface wave dispersion tomography, were also useful tools applied in the region over the past decade. These have been improved by the addition of temporary and permanent regional seismological arrays and stations. An interesting NNW-SSE Moho depth anomaly, pointing to crustal thickening of up to 60 km in the central Guyana shield and a 50 km thick anomaly of the southern Central Brazil shield were recently identified. Areas with crustal thickening correspond to Paleoproterozoic magmatic arcs. The upper mantle seismic anisotropy in part of the region has been determined from SKS splitting studies. The currently available seismic anisotropy information shows that the orientation of the determined anisotropic axis is related to the frozen in anisotropy hypothesis for the Amazonian craton. The orientation of the anisotropic axis shows no relation to the current South American plate motion in the Amazonian craton. Most recently, detailed information for the two shields has benefited from a series of high-resolution, regional aerogeophysical surveys, made available by CPRM, the Brazilian Geological Survey. In addition to the mentioned contribution from seismology for imaging deeper crustal structures, regional gravity surveys have been expanded, adding to previous Bouguer anomaly maps, and deep drilling information from early exploration efforts have been compiled for the Amazon basin, which covers the Amazonian craton separating the Guyana and Central Brazil shields.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of South American Earth Sciences - Volume 70, October 2016, Pages 162–173
نویسندگان
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