Enhancement of the total horizontal gradient of magnetic anomalies using tilt derivatives: Part II — Application to real data

Ferreira, Francisco José Fonseca; Castro, Luís Gustavo de; Bongiolo, Alessandra B.S.; Souza, Jeferson de; Romeiro, Marco Antonio Thoaldo

doi:10.1190/1.3628216

Cited by 14 publications

(13 citation statements)

References 9 publications

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“…The THD filter is used for multi-scale edge detection through aeromagnetic data (Archibald et al, 1999; Blenkinsop, 2008, 2009;Henson et al, 2010;Holden et al, 2000). Ferreira et al (2011) proposed that applying tilt derivative (TDR) filter on the THD data facilitates the enhancement and visualization of magnetic edges. The TDR filter has been widely applied on aeromagnetic data for enhancement of magnetic edges and bodies (e.g., Ma and Li, 2012;Miller and Singh, 1994;Salem et al, 2007;Verduzco et al, 2004).…”

Section: Pathway Evidence Mapmentioning

confidence: 99%

Section: Conceptual Model Of Orogenic Gold Deposits and Exploration Cmentioning

confidence: 99%

“…Thus, in order to detect the edges of aeromagnetic anomalies we applied total horizontal derivative (THD) filter (Airo, 2001(Airo, , 2007Bierlein et al, 2006a,b Henson et al, 2010Ferreira et al, 2011;Almasi et al, 2014). The THD filter is used for multi-scale edge detection through aeromagnetic data (Archibald et al, 1999;Blenkinsop, 2008, 2009;Henson et al, 2010;Holden et al, 2000).…”

Section: Pathway Evidence Mapmentioning

confidence: 99%

“…Additionally, mylonitic granites and altered mylonitic granites, which were indicated as a secondary host rocks, have relatively higher radioactiveelements content in their minerals (feldspar, plagioclase, zircon: Aliyari, 2006; Tajeddin, 2011) than other rock units of the study area and can be detected using airborne geophysical survey. Furthermore, because the geological units have various magnetic characteristics, contacts and discontinuities between these units can be identified efficiently using edge detection methods (Airo, 2001(Airo, , 2007 Bierlein et al, 2006a,b;Henson et al, 2010;Ferreira et al, 2011;Almasi et al, 2014).Based on the characteristics of orogenic gold deposits in well-explored areas as well as in the study area of this paper, the localization of orogenic gold deposits within an endowed geological setting requires the synthesis of several critical factors, which can be defined in terms of a minerals system. These factors are (e.g., Groves et al, 2000;Bierlein et al, 2006a;Aliyari et al, 2009Aliyari et al, , 2012Tajeddin, 2011;: (1) metal source(s); (2) superior structural plumbing systems, such as fault, geological contact, and shear zones; and (3) ore trap such as reactive host rocks.…”

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Prospectivity analysis of orogenic gold deposits in Saqez-Sardasht Goldfield, Zagros Orogen, Iran

Almasi

Yousefi

Carranza

2017

Ore Geology Reviews

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Diverse deposit-types or mineral systems form by diverse geological processes, so translation of knowledge about the controls of mineralization acquired from the 4D geological modeling into 2D spatial predictor maps is a major challenge for prospectivity analysis. In this regard, mathematical functions have been used to model the conceptual or perceived spatial relationships between geological variables and targeted type or system of mineralization. In this paper, due to the different models of spatial relationships between predictors and mineral deposits, we investigated the performance of different fuzzification functions to quantify the relationships. We demonstrated that various types of relationships between exploration features and a mineralization-type sought could be quantified using different fuzzification functions for prospectivity analysis. We illustrated the process of the prospectivity analysis by using a data set of orogenic gold deposits in Saqez-Sardasht Goldfield, Iran. Prospectivity modeling of orogenic gold mineralization in the study area showed that the NE-SW trending targets have priority for further prospecting of the deposits. Saqez-Sardasht Goldfield, Zagros Orogen, Iran (by A. Almasi, M. Yousefi, E. J.M. Carranza) Manuscript submitted to Ore Geology Reviews 2 Prospectivity analysis of orogenic gold deposits in IntroductionFor mineral prospectivity mapping (MPM) of a deposit-type sought in an area, mathematical functions have been used to model spatial relationships between geological variables system of mineralization (e.g., Bonham-Carter, 1994;Luo and Dimitrakopoulos, 2003; Porwal et al., 2003a,b,c;Carranza, 2008Carranza, , 2017. In MPM, mathematical functions, have been widely used to assign weights to discretized spatial evidence values as fuzzified evidential maps in the [0,1] range or to rank target areas as fuzzy prospectivity models (e.g., Bonham-Carter, 1994;Carranza and Hale, 2002;Luo and Dimitrakopoulos, 2003;Porwal et al., 2003c;Carranza, 2008Carranza, , 2009Carranza, , 2017Lisitsin et al., 2013;Mutele et al., 2017;Nykänen et al., 2017). The weights assigned to classes of discretized evidential values may be based on (a) expert judgment directly, (b) locations of known mineral occurrences (KMOs), (c) a combination of (a) and (b), or (d) subjectively-defined functions, so indirectly-assigned by analyst (e.g., Luo, 1990;Bonham-Carter, 1994;Cheng and Agterberg, 1999;Luo and Dimitrakopoulos, 2003;Porwal et al., 2003a Porwal et al., ,b,c, 2004Porwal et al., , 2006Carranza et al., 2005;Carranza, 2008Carranza, , 2014Porwal and Kreuzer, 2010;Mejía-Herrera et al., 2014;Carranza and Laborte, 2016;McKay and Harris, 2016). All these methods impart bias due to discretization of continuous spatial values, use of subjective expert judgments, and sparse or incomplete data on locations of KMOs in knowledge-and data-driven MPM (Coolbaugh et al., 2007;Lusty et al., 2012;Ford et al., 2016).To reduce bias in the assignment of weights to continuous-value spatial evidence, various re...

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Section: Pathway Evidence Mapmentioning

confidence: 99%

Section: Conceptual Model Of Orogenic Gold Deposits and Exploration Cmentioning

confidence: 99%

Section: Pathway Evidence Mapmentioning

confidence: 99%

mentioning

confidence: 99%

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Prospectivity analysis of orogenic gold deposits in Saqez-Sardasht Goldfield, Zagros Orogen, Iran

Almasi

Yousefi

Carranza

2017

Ore Geology Reviews

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“…The total horizontal derivative (THD) technique is the fastest and more efficient approach in estimating contact locations of causative bodies at crustal depths. This efficiency is as a result of its ability to give a peak anomaly over the magnetic contacts [69][70][71]. The technique is known for its low sensitivity to noise in the magnetic data because it essentially requires the computation of the first-order horizontal derivatives of the magnetic field in the x-and y-directions.…”

Section: Total Horizontal Derivative (Thd)mentioning

confidence: 99%

Structural and hydrothermal alteration mapping related to orogenic gold mineralization in part of Kushaka schist belt, North-central Nigeria, using airborne magnetic and gamma-ray spectrometry data

Sanusi

Amigun

2020

SN Appl. Sci.

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This paper presents an interpretation of airborne magnetic and gamma-ray spectrometry data over a part of the Kushaka schist belt of Nigeria with a view to assess the sub-surface structural framework and hydrothermal alteration haloes that are related to orogenic gold mineralization in the study area. The geophysical analyses performed to improve the quality of the aeromagnetic data for better understanding of the subsurface geology were reduction to the equator, upward continuation, total horizontal derivative, analytical signal, source edge detection, tilt-angle derivative of total horizontal derivative. The analyses performed on the airborne gamma-ray spectrometry data were made on K/eTh, F parameter and deviation of ideal K values (Kd). Deep-seated, brittle-ductile shear/fracture zones with characteristic depth of 428.0-607.6 m and area extent of 15.5 km by 6.5 km that were delineated in the area coincide with beehive of artisanal miners exploiting gold deposits. In this study, subsurface geologic structures, specifically dykes/faults, that trend in the ENE-WSW direction constitute a first-order control on orogenic gold mineralization in the study area. The hydrothermally altered zones mapped in the area indicated they are structurally controlled and closely associated with orogenic gold mineralization. Apart from geologic structural evidences that are controlling orogenic gold mineralization, this study has indicated that hydrothermal alteration mapping is equally important for a promising orogenic gold mineralization mapping.

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Magnetic Data Interpretation for the Source-Edge Locations in Parts of the Tectonically Active Transition Zone of the Narmada-Son Lineament in Central India

Ghosh

2015

Pure Appl. Geophys.

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Enhancement of the total horizontal gradient of magnetic anomalies using tilt derivatives: Part II — Application to real data

Cited by 14 publications

References 9 publications

Prospectivity analysis of orogenic gold deposits in Saqez-Sardasht Goldfield, Zagros Orogen, Iran

Prospectivity analysis of orogenic gold deposits in Saqez-Sardasht Goldfield, Zagros Orogen, Iran

Structural and hydrothermal alteration mapping related to orogenic gold mineralization in part of Kushaka schist belt, North-central Nigeria, using airborne magnetic and gamma-ray spectrometry data

Magnetic Data Interpretation for the Source-Edge Locations in Parts of the Tectonically Active Transition Zone of the Narmada-Son Lineament in Central India

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