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Hesham M Harbi - One of the best experts on this subject based on the ideXlab platform.
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utilization of spot 5 data for mapping gold mineralized diorite Tonalite intrusion bulghah gold mine area saudi arabia
Arabian Journal of Geosciences, 2014Co-Authors: Hesham M Harbi, Ahmed MadaniAbstract:The present study utilizes the processed SPOT 5 data to discriminate and to generate 1:10,000 geologic image map to delineate the mineralized diorite–Tonalite intrusion around Bulghah gold mine area, Saudi Arabia. The rock units exposed in the area include gossan, marble, Hulayfah volcanics, diorite–Tonalite, gneissose granite, and alkali granite. Gold mineralization at Bulghah mine is hosted mainly by Syn- to Late-tectonic diorite–Tonalite intrusion aligned along N–S direction and is associated mainly with cataclastic zones and quartz veins. Gossans and jasparoidal gossans (Hulayfah group), recorded at the western side of Bulghah mine area as discontinuous small lenses, can be easily discriminated on 4/2 and 4/3 band ratio SPOT images by their white and black image signatures, respectively. Granitoids (gneissose granite and alkali granite) are easily discriminated in 3/2 ratio image, in which gneissose granite has gray image signature, whereas alkali granite has dark gray image signature. On the SPOT false color composite band ratios image (3/2 R, 4/2 G, and 4/3 B), gossan, marble, Hulayfah volcanics, diorite–Tonalite, gneissose granite, and alkali granite have sky blue, blood red, bluish light brown, orange, brick red, and deep blue colors, respectively. Fusion of the false color composite SPOT ratios image (3/2 R, 4/2 G, and 4/3 B) with the high spatial resolution SPOT pan image is performed using IHS transformation method. The fused image is used to delineate the mineralized diorite–Tonalite intrusion and to produce 1:10,000 geologic image map for Bulghah gold mine area. The present study reveals the usefulness of the processed SPOT 5 data for adding new extensions at the southern and northern boundaries of diorite–Tonalite intrusion.
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spectroscopy of the mineralized Tonalite diorite intrusions bulghah gold mine area saudi arabia effects of opaques and alteration products on fieldspec data
Ore Geology Reviews, 2012Co-Authors: Ahmed Madani, Hesham M HarbiAbstract:Abstract This paper aims to reveal the spectral characteristics of the mineralized Tonalite–diorite intrusions exposed at Bulghah gold mine area, Saudi Arabia, using FieldSpec spectroradiometer and Landsat ETM + data. Gold mineralization at Bulghah gold mine is hosted mainly by Syn- to Late-orogenic Tonalite–diorite intrusions aligned in N–S direction and is associated mainly with cataclastic zones and quartz veins. Based on field, petrography and FieldSpec data two main Tonalite–diorite groups namely A and B are recognized. Group “A”, recorded at the mine area, is characterized by low flat spectral profiles with overall low reflectance values (~ 10%). These low values are attributed to the presence of high content of trans-opaque phases (hematite and goethite) as indicated by petrographic study. Spectral profiles of group “B”, recorded at Bulghah North area, show high reflectance values (~ 40%) with three main absorption features around the 1.45 μm, 2.20 μm and 2.35 μm wavelength regions. These absorption features are attributed mainly to the presence of clay minerals, sericite, chlorite and carbonate alteration products. To discriminate the above mentioned Tonalite–diorite groups, band ratios and Minimum Noise Fraction (MNF) techniques are conducted. Landsat false color composite band ratio image (7/4:R, 4/1:G and 4/5:B) discriminates easily the bluish brick red Tonalite–diorite intrusions from the surrounding rock units but failed to distinguish the above mentioned two Tonalite–diorite groups. On MNF3 image, the two Tonalite–diorite groups can be distinguished easily in which group “A” has white color whereas group “B” has gray color. The present study proved the usefulness of FieldSpec spectral profiles and the processed Landsat ETM + data for discriminating and delineating the mineralized Tonalite–diorite intrusions exposed at the study area.
Ahmed Madani - One of the best experts on this subject based on the ideXlab platform.
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utilization of spot 5 data for mapping gold mineralized diorite Tonalite intrusion bulghah gold mine area saudi arabia
Arabian Journal of Geosciences, 2014Co-Authors: Hesham M Harbi, Ahmed MadaniAbstract:The present study utilizes the processed SPOT 5 data to discriminate and to generate 1:10,000 geologic image map to delineate the mineralized diorite–Tonalite intrusion around Bulghah gold mine area, Saudi Arabia. The rock units exposed in the area include gossan, marble, Hulayfah volcanics, diorite–Tonalite, gneissose granite, and alkali granite. Gold mineralization at Bulghah mine is hosted mainly by Syn- to Late-tectonic diorite–Tonalite intrusion aligned along N–S direction and is associated mainly with cataclastic zones and quartz veins. Gossans and jasparoidal gossans (Hulayfah group), recorded at the western side of Bulghah mine area as discontinuous small lenses, can be easily discriminated on 4/2 and 4/3 band ratio SPOT images by their white and black image signatures, respectively. Granitoids (gneissose granite and alkali granite) are easily discriminated in 3/2 ratio image, in which gneissose granite has gray image signature, whereas alkali granite has dark gray image signature. On the SPOT false color composite band ratios image (3/2 R, 4/2 G, and 4/3 B), gossan, marble, Hulayfah volcanics, diorite–Tonalite, gneissose granite, and alkali granite have sky blue, blood red, bluish light brown, orange, brick red, and deep blue colors, respectively. Fusion of the false color composite SPOT ratios image (3/2 R, 4/2 G, and 4/3 B) with the high spatial resolution SPOT pan image is performed using IHS transformation method. The fused image is used to delineate the mineralized diorite–Tonalite intrusion and to produce 1:10,000 geologic image map for Bulghah gold mine area. The present study reveals the usefulness of the processed SPOT 5 data for adding new extensions at the southern and northern boundaries of diorite–Tonalite intrusion.
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spectroscopy of the mineralized Tonalite diorite intrusions bulghah gold mine area saudi arabia effects of opaques and alteration products on fieldspec data
Ore Geology Reviews, 2012Co-Authors: Ahmed Madani, Hesham M HarbiAbstract:Abstract This paper aims to reveal the spectral characteristics of the mineralized Tonalite–diorite intrusions exposed at Bulghah gold mine area, Saudi Arabia, using FieldSpec spectroradiometer and Landsat ETM + data. Gold mineralization at Bulghah gold mine is hosted mainly by Syn- to Late-orogenic Tonalite–diorite intrusions aligned in N–S direction and is associated mainly with cataclastic zones and quartz veins. Based on field, petrography and FieldSpec data two main Tonalite–diorite groups namely A and B are recognized. Group “A”, recorded at the mine area, is characterized by low flat spectral profiles with overall low reflectance values (~ 10%). These low values are attributed to the presence of high content of trans-opaque phases (hematite and goethite) as indicated by petrographic study. Spectral profiles of group “B”, recorded at Bulghah North area, show high reflectance values (~ 40%) with three main absorption features around the 1.45 μm, 2.20 μm and 2.35 μm wavelength regions. These absorption features are attributed mainly to the presence of clay minerals, sericite, chlorite and carbonate alteration products. To discriminate the above mentioned Tonalite–diorite groups, band ratios and Minimum Noise Fraction (MNF) techniques are conducted. Landsat false color composite band ratio image (7/4:R, 4/1:G and 4/5:B) discriminates easily the bluish brick red Tonalite–diorite intrusions from the surrounding rock units but failed to distinguish the above mentioned two Tonalite–diorite groups. On MNF3 image, the two Tonalite–diorite groups can be distinguished easily in which group “A” has white color whereas group “B” has gray color. The present study proved the usefulness of FieldSpec spectral profiles and the processed Landsat ETM + data for discriminating and delineating the mineralized Tonalite–diorite intrusions exposed at the study area.
Antonio Castro - One of the best experts on this subject based on the ideXlab platform.
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atypical peri gondwanan granodiorite Tonalite magmatism from southern iberia origin of magmas and implications
Lithos, 2020Co-Authors: Antonio Castro, M F Pereira, Carmen Cristofol Rodriguez, Carlos Fernandez, Jesus D De La RosaAbstract:Abstract An ensemble of fifteen granodiorite/Tonalite plutons and minor intrusions was generated during Cambro-Ordovician times (ca. 498–462 Ma) at the margin of Gondwana, which occupies a large portion of the Central Iberian Zone of the Iberian Massif (Spain and Portugal). This ensemble is known as the Beira-Extremadura batholith (BEB), which is mainly composed of tonalities and granodiorites (>90 vol%) and shows an atypical composition, with values of ASI (alumina saturation index) ≈ 1.2 on average, and marked calc-alkaline affinity in terms of major and trace elements. SHRIMP zircon U-Pb ages of 476 ± 7 Ma, 476 ± 6 Ma, and 474 ± 7 Ma for Montanchez, Santa Cruz de la Sierra and Valdemorales Tonalites, respectively, coincide within uncertainty with the age of other Lower Ordovician BEB intrusions. Analysis of phase relations and comparisons with experimental results on cotectic liquid compositions, indicate that these atypical rocks represent calc-alkaline magmas that carried exogenous pelitic restites from depth. Assimilation of partially molten metasediments by invasion of calc-alkaline magmas is a plausible explanation. Model mixing of experimental calc-alkaline liquids and Ediacaran metasedimentary rocks yields that 20% (up to 40% in samples of the Santa Cruz Pluton) of assimilated metagreywackes and metapelites is required to account for geochemical atypical compositions departing from a main cotectic array of calc-alkaline systems. The processes of melting or melting plus assimilation are favored by addition of water-rich fluids. We propose a tectonic scenario of crustal extension and metasomatized mantle melting that supplied hydrous intermediate magmas to the crust triggering crustal melting and massive assimilation of metasediments.
Jesus D De La Rosa - One of the best experts on this subject based on the ideXlab platform.
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atypical peri gondwanan granodiorite Tonalite magmatism from southern iberia origin of magmas and implications
Lithos, 2020Co-Authors: Antonio Castro, M F Pereira, Carmen Cristofol Rodriguez, Carlos Fernandez, Jesus D De La RosaAbstract:Abstract An ensemble of fifteen granodiorite/Tonalite plutons and minor intrusions was generated during Cambro-Ordovician times (ca. 498–462 Ma) at the margin of Gondwana, which occupies a large portion of the Central Iberian Zone of the Iberian Massif (Spain and Portugal). This ensemble is known as the Beira-Extremadura batholith (BEB), which is mainly composed of tonalities and granodiorites (>90 vol%) and shows an atypical composition, with values of ASI (alumina saturation index) ≈ 1.2 on average, and marked calc-alkaline affinity in terms of major and trace elements. SHRIMP zircon U-Pb ages of 476 ± 7 Ma, 476 ± 6 Ma, and 474 ± 7 Ma for Montanchez, Santa Cruz de la Sierra and Valdemorales Tonalites, respectively, coincide within uncertainty with the age of other Lower Ordovician BEB intrusions. Analysis of phase relations and comparisons with experimental results on cotectic liquid compositions, indicate that these atypical rocks represent calc-alkaline magmas that carried exogenous pelitic restites from depth. Assimilation of partially molten metasediments by invasion of calc-alkaline magmas is a plausible explanation. Model mixing of experimental calc-alkaline liquids and Ediacaran metasedimentary rocks yields that 20% (up to 40% in samples of the Santa Cruz Pluton) of assimilated metagreywackes and metapelites is required to account for geochemical atypical compositions departing from a main cotectic array of calc-alkaline systems. The processes of melting or melting plus assimilation are favored by addition of water-rich fluids. We propose a tectonic scenario of crustal extension and metasomatized mantle melting that supplied hydrous intermediate magmas to the crust triggering crustal melting and massive assimilation of metasediments.
Fred J. Longstaffe - One of the best experts on this subject based on the ideXlab platform.
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Fluid-present Anatexis of Neoarchean Tonalite and Amphibolite in the Western Shandong Province
Lithos, 2019Co-Authors: Chris Yakymchuk, Wenran Zhao, Yusheng Wan, Shoufa Lin, Fred J. LongstaffeAbstract:Abstract MetaTonalite and amphibolite from the Taishan region of the Western Shandong Province in the North China Craton record c. 2.60 Ga fluid-present partial melting via the breakdown of biotite, plagioclase and quartz to produce peritectic hornblende and anatectic melt. Eight paired leucosome–melanosome samples from metaTonalite and three paired samples from amphibolite were investigated to evaluate the composition of the melt. Hornblende, biotite and plagioclase in the leucosomes and hornblende and plagioclase in melanosomes from both rock types have similar compositions. Two leucosome samples from the metaTonalite were influenced by the removal of heavy rare earth element-rich hornblende and the accumulation of plagioclase. The other leucosomes are interpreted to represent near initial melt compositions with a minor component of peritectic hornblende and are enriched in Si, Na and Sr and depleted in K, Ca, Ba and Rb relative to melanosomes. The enrichment of Na in the melt is inconsistent with experimental results of fluid-present melting of Tonalite, but is broadly consistent with the experimental results of fluid-fluxed melting of amphibolite. The absence of K-feldspar in both rock types is a critical control on the composition of anatectic melt and initial melt compositions were probably similar for both rock types. Leucosomes inherited rare earth element patterns from their sources, which suggests that some trace element diagrams used to infer tectonic settings and depths of melting are not appropriate for reworked components of Archean grey gneisses. Whole-rockδ18O suggest that the fluids responsible for inducing local melting were derived from the intrusion and crystallization of ~2.60 Ga Tonalites and trondhjemites in the Taishan region. One amphibolite sample has a relatively low δ18O suggestive of interaction with meteoric water or seawater possibly related to crustal extension and asthenosphere upwelling at ~2.60 Ga. Fluid-present partial melting reworked 2.75–2.60 Ga Tonalites and amphibolites, generating ~2.60 Ga sodium-rich components of grey gneisses in the Western Shandong Province.
