Proterozoic first-order sedimentary sequences of the S茫o Francisco craton, eastern Brazil

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• 作者：Fernando F. Alkmim^a ; ^{ffalkmim@gmail.com} ; ^{alkmim@degeo.ufop.br} ; Marcelo A. Martins-Neto^b
• 关键词：First-order sequences ; Proterozoic ; Sã ; o Francisco craton ; Brazil
• 刊名：Marine and Petroleum Geology
• 出版年：2012
• 期刊代码：37_02648172
• 类别：pw
• 出版时间：May, 2012
• 卷：33
• 期：1
• 页码：127-139
• 文件大小：3749 K

摘要

The S茫o Francisco craton in eastern Brazil hosts sedimentary sequences deposited between the Paleoarchean (鈭?300聽Ma) and Late Neoproterozoic (鈭?80聽Ma). Proterozoic successions occurring in this region comprise five 1st-order sedimentary sequences, which besides episodes of global significance record major basin-forming events. The ca. 8000聽m-thick Minas-Itacolomi 1st-order sequence, exposed in the Brazilian mining district of the Quadril谩tero Ferr铆fero and containing as marker bed the Lake Superior-type Cau锚 Banded Iron Formation, tracks the operation of a Wilson cycle in the Paleoproterozoic Era. The quartz-arenite dominated Espinha莽o I and II sequences record at least two major rift-sag basin-forming events, which affected the host continent of the S茫o Francisco craton at around 1.75聽Ga and 1.57聽Ga. The Maca煤bas sequence and its correlatives in the extracratonic domains witness the individualization of a S茫o Francisco-Congo plate in synchronicity with the break-up of Rodinia in the Cryogenian period. The S茫o Francisco-Congo plate together with various fragments derived from Rodinia reassembled to form Gondwana in the Ediacaran period. In the course of the Gondwana amalgamation, orogenic belts developed along the margins of the craton; its interior, converted into foreland basins, received the shallow water carbonates and pelites of the Bambu铆 1st-order sequence and its correlatives.