Universidade Federal da Bahia, Instituto Rua Barão de Geremoabo, s/n, Campus Universitário de Ondina, Ondina, 40170-290 Salvador, BA, Brazil.
An Acad Bras Cienc. 2021 Mar 24;93(1):e20200178. doi: 10.1590/0001-3765202120200178. eCollection 2021.
The transition zone between the Archean blocks, Jequié and Itabuna-Salvador-Curaçá, in the county of Laje, Bahia, Brazil, is potentially important for iron ore deposits of economic interest. This research investigates one of the eighteen anomalies defined by a previous integrated interpretation of geological and airborne gamma ray spectrometry and magnetic data in this transition zone. Its choice resulted from being located in an area with intense transcurrent shear and from the occurrence of pebbles rich in magnetite. Because of paucity of surface geological information, a ground-based geophysical survey added valuable information for the definition of a drilling program in the area. The survey consisted of two parts and followed up the aforementioned previous integrated interpretation of the Valença sheet. The first part consisted of one gravity and magnetic profile, which indicated a favorable site for additional investigation. The second part consisted of a detailed survey in the selected area with gravity, magnetic, and VLF-EM. The interpretation of the data of the geophysical methods allowed to delineate two zones in the area, both located at magnetic anomalies, gravity highs and relatively conductive parts. The two zones have a high potential for iron ore, because they present significant and correlated anomalies.
巴西巴伊亚州拉热市的杰奎、伊塔布纳-萨尔瓦多-库里亚卡弧形地块之间的过渡带，具有形成经济利益铁矿石矿床的潜力。本研究调查了该过渡带地质和航空伽马射线能谱及磁力数据综合解释之前确定的 18 个异常之一。之所以选择这个异常，是因为它位于一个横切剪切作用强烈的区域，并且存在富含磁铁矿的卵石。由于地表地质信息匮乏，地面地球物理调查为该区域的钻井计划提供了有价值的信息。该调查由两部分组成，是对前文提到的瓦伦萨图幅的综合解释的后续。第一部分由一条重力和磁力剖面组成，该剖面显示了一个有利于进一步调查的地点。第二部分是在选定区域进行的详细重力、磁力和甚低频电磁测量。对地球物理方法数据的解释，在该区域划定了两个区域，这两个区域都位于磁异常、重力高和相对导电部分。这两个区域具有很高的铁矿石潜力，因为它们存在显著且相关的异常。
