Interpretation of geophysical data for iron ore detailed survey in Laje, Bahia, Brazil

Abstract

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.

Estimation of Depth, Physical Parameters, and Location using Nonlinear Inverse Modeling of Magnetic Data by Bhattacharya Method in a field of NW Iran

“…Meanwhile, the gravimetric method is also used as auxiliary and complementary methods (Abedi et al, 2015;Doulati Ardejani et al, 2011;Hosseini et al, 2013;Hosseini et al, 2014). Often, in the studied areas, due to the outcrops of magnetite seen on the earth surface and their relationship with existing tectonic systems, the pursuit of these iron-bearing zones in-depth, as well as the extent of their expansion in different directions, has necessitated the performance of magnetometric operations (Blakely, 1995;Blakely & Simpson, 1986;Hinze, 1990;Hinze & Von Frese, 1990; Moradzadeh et al, 2021;Sampaio et al, 2021;Yadav et al, 2022).…”

“…An optimized combination of geophysical survey methods was capable by Fu et al (2020) for taking single-point, continuous measurements (e.g., the high-precision ground magnetic survey (HPGMS), the transient electromagnetic (TEM), and the magnetotelluric (MT) methods) can be employed to accurately determine the anomalous planar spatial locations, anomalous pro le morphologies, and burial depths of concealed iron ore bodies such as banded iron formation (BIF)-type (Florio et al, 2022;Fu et al, 2020), and the survey helped to characterize subsurface geology better (Madani et al, 2019). Finally, used magnetic data were used to improve neighboring bodies' resolution and densify the information, pro le, and 2D survey by Sampaio et al (2021).…”

Geobody Estimation by Bhattacharyya Method Utilizing Nonlinear Inverse Modeling of Magnetic Data in Baba-Ali Iron Deposit, NW Iran

“…Meanwhile, the gravity method is also auxiliary and complementary (Abedi et al, 2015;Doulati Ardejani et al, 2011;Hosseini et al, 2013;Hosseini et al, 2014). Often, in the studied areas, due to the outcrops of magnetite seen on the earth's surface and their relationship with existing tectonic systems, the pursuit of these iron-bearing zones in-depth, as well as the extent of their expansion in different directions, has necessitated the performance of magnetic operations (Blakely, 1995;Blakely & Simpson, 1986;Hinze, 1990;Hinze & Von Frese, 1990;Moradzadeh et al, 2021;Sampaio et al, 2021;Yadav et al, 2022). In addition, the magnetic method is used as a geophysical method with high and inexpensive survey efficiency in most mineral potentials, especially in iron-bearing areas, so it is before other geophysical methods in this regard (Doulati Ardejani et al, 2011;Moradzadeh et al, 2005;Paterson & Reeves, 1985;Shakiba et al, 2018).…”

“…An optimized combination of geophysical survey methods was capable by Fu et al (2020) for taking single-point, continuous measurements (e.g., the high-precision ground magnetic survey (HPGMS), the transient electromagnetic (TEM), and the magnetotelluric (MT) methods) can be employed to accurately determine the anomalous planar spatial locations, anomalous profile morphologies, and burial depths of concealed iron ore bodies such as banded iron formation (BIF)-type (Florio et al, 2022;Fu et al, 2020), and the survey helped to characterize subsurface geology better (Madani et al, 2019). Furthermore, magnetic data were used to improve neighboring bodies' resolution and densify the information, profile, and 2D survey by Sampaio et al (2021). As the application of magnetic inversion methods in recent years, a transient electromagnetic induction was used to detection of near-surface horizontal anisotropy in weathered metamorphic schist at Llano Uplift, Texas (Collins et al, 2006).…”

Geobody Estimation by Bhattacharyya Method Utilizing Nonlinear Inverse Modeling of Magnetic Data in Baba-Ali Iron Deposit, NW Iran

“…Meanwhile, the gravity method is also auxiliary and complementary Doulati Ardejani et al, 2011;Essa et al, 2021b;Hosseini et al, 2013;Hosseini et al, 2014). Often, in the studied areas, due to the outcrops of magnetite seen on the earth's surface and their relationship with existing tectonic systems, the pursuit of these iron-bearing zones in-depth, as well as the extent of their expansion in different directions, has necessitated the performance of magnetic operations (Blakely, 1995;Blakely & Simpson, 1986;Hinze, 1990;Hinze & Von Frese, 1990;Moradzadeh et al, 2021;Sampaio et al, 2021;Yadav et al, 2022).…”