Geology and geochemistry of palaeoproterozoic low-grade metabasic volcanic rocks from Salumber area, Aravalli Supergroup, NW India

Shekhawat, L. S.; Pandit, Manoj K.; Joshi, Dev

doi:10.1007/s12040-007-0034-2

Cited by 5 publications

(6 citation statements)

References 31 publications

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“…In fact, these diagrams, particularly the Nb/Y-Zr/TiO 2 diagram of Winchester & Floyd (1977), have been in wide use even today. Just to name a few references during 2007−2008, we can cite: Gökten & Floyd (2007); Shekhawat et al (2007); Ahmad et al (2008); Bağcı et al (2008); Gladkochub et al (2008); Gürsü (2008); Kadir et al (2008); Keskin et al (2008); Kalmar & Kovacs-Palffy (2008); Kaygusuz et al (2008); Mondal et al (2008); Nardi et al (2008); Pandarinath et al (2008); Wang et al (2008); Yiğitbaş et al (2008); and Zheng et al (2008). On the other hand, others, such as Sheth & Melluso (2008), have used the SINCLAS program for the TAS classification.…”

Section: Introductionmentioning

confidence: 99%

Multidimensional Classification for Altered Igneous Rocks

Verma

2019

Road From Geochemistry to Geochemometrics

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The International Union of Geological Sciences (IUGS) has proposed recommendations for the classification of relatively fresh volcanic rocks, but with no specific instructions for altered volcanic rocks, other than discouraging the use of the total alkalis versus silica diagram. The Nb/Y-Zr/TiO 2 diagram has been in use for the classification of altered rocks now for over 30 years. Recently (during 2007) another diagram (Co-Th) has been proposed to replace this old diagram, particularly for altered arc rocks. Using an extensive database of all kinds of relatively fresh rocks from four tectonic settings (island arc, continental rift, ocean island, and mid-ocean ridge), as well as from three settings excluding island arc, we carried out an objective evaluation of the old Nb/Y-Zr/TiO 2 diagram for rock classification. Similarly, for the evaluation of the new Co-Th diagram, an extensive database of similar rocks from island arcs, the Andean active continental margin, continental rifts, ocean islands, and the Mexican Volcanic Belt, was used. Statistical parameters of correct classification or success rate and minimum misclassification defined in this work, respectively, were used to evaluate these diagrams. Our results of the quantification of these parameters showed that none of these diagrams seems to work precisely for the classification of fresh rocks. It is therefore difficult to imagine that they would work well for the classification of altered rocks. Thus, there is an urgent need to apply correct statistical methodology for handling compositional data in proposing new classification diagrams that could provide classification and nomenclature to altered volcanic rocks fully consistent with the IUGS nomenclature for fresh rocks.

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Section: Introductionmentioning

confidence: 99%

Multidimensional Classification for Altered Igneous Rocks

Verma

2019

Road From Geochemistry to Geochemometrics

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“…Proximal to Bhukia area, the basal Aravalli volcanic rocks are well exposed in Salumber region that are coeval to the Delwara–Nathdwara volcanic rocks. Shekhawat, Pandit, and Joshi () have carried out geochemical studies of these volcanic rocks and concluded that (a) the bulk of the Salumber volcanic rocks have high‐Mg tholeiitic basalt chemistry albeit a few rocks that reflect komatiitic chemistry; (b) these rocks reflect enrichment of LREE, incompatible elements, similar to continental tholeiites or P‐type MORB; (c) the enriched continental signatures in primitive high Mg tholeiite (and komatiites) are inferred to suggest enriched source regions, possibly reworking of an old subcontinental lithosphere; and (d) similar to the Nathdwara–Delwara volcanics, the trace and rare element chemistry of the Salumber volcanic rocks point towards a complex evolutionary history and diverse and transitional source characteristics mainly between Within Plate and MORB settings.…”

Section: Resultsmentioning

confidence: 99%

Geochemical characterization of mineralized albitite from Paleoproterozoic Bhukia IOCG‐IOA deposit of Aravalli‐Delhi Fold Belt, Rajasthan, western India: Genetic linkage to the gold (±Cu ± U) mineralization

2019

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Paleoproterozoic Bhukia gold deposit is located within the Debari Group of Aravalli Supergroup, Rajasthan, northwestern India. The major lithounits that are associated with gold-graphite (±Cu ± U) mineralization exposed in Bhukia are albitite, carbonates, and quartzite which have undergone upper greenschist to amphibolite facies metamorphism. Ore mineralization viz. pyrrhotite, arsenopyrite, chalcopyrite, pyrite, graphite, magnetite, and goethite in the study area are associated with NNW-SSE trending shear zone. Nuggets of gold are identified in the thick gossan zones that occurs parallel to the shear zone. The gold-sulfide lodes of the Bhukia deposits are largely confined either to marble or albitized marble and pure monomineralic albitite.The mineralization that is associated with the albitite, follows the boundaries of albite grains which confirms the role of these weak zones for the mobilization of mineralizing fluid and concentration of metal ions. Hence, geochemical studies of albitite would help to evaluate the petrogenesis, likely magmatic affinity, tectonic setting, controls of the mineralizing fluid, source, and their linkage to the gold (±Cu ± U) metallogeny. Bhukia albitite is characterized by Na-Al-rich and K-poor compositions along with metaluminous nature. Geochemical analysis of various key elements suggests that albitite is the product of low-K calc-alkaline magma series with variation in Nb/Ta ratio indicating their fractionation during the melt-rock interaction within the shear zone. Geochemical signatures suggest the role of upper continental crust in channelizing the mineralized fluids that generated albitite with felsic to intermediate composition in and around Bhukia deciphered from their low Nb/Y ratios. Lower concentration of compatible elements (Ni and Cr) and higher concentration of incompatible elements (Th, La, and Nd) with SiO 2 suggest that evolution of albitite rock is related to the fractional crystallization process. Zr/Hf ratios of 9-35 with the average of 18 suggest that albitite formed under magmatic-hydrothermal transitional environment. Rare Earth Elements (REE) patterns of albitite samples are moderately fractionated showing Light Rare Earth Elements (LREE)-enrichment with a rather steep slope and exhibit distinct negative Eu anomalies (0.42-0.71, average 0.57). The enrichment of LREE in comparison to the Heavy Rare Earth Elements (HREE) suggests a more evolved source, i.e., process of melting at shallow environments. Tectonic setting of albitite samples suggest their origin in a volcanic arc region that underwent rifting. Detailed geochemical characterization unravelled complex evolutionary history of albitite in the Bhukia area, which attests derivation of the parental melt possibly from an enriched SCLM (Sub-continental lithospheric mantle) source similar to most of the IOCG-IOA deposits worldwide.

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“…Located 130 km ESE of Udaipur, it represents the southeastern extension of the stratigraphic units of the Aravalli type-section (Heron, 1953). Towards the southeast margin, near Salumber, the volcanic rocks are high-Mg tholeiitic basalts and komatiites that reflect enriched LREE and incompatible elements (similar to continental tholeiites or P-type MORB; Shekhawat et al, 2007). The quartzite/conglomerate at the base directly overlies the BGC belong to a well developed Debari Group of rocks.…”

Section: Aravalli Succession In Salumber-bhukia-ghatol Sectionmentioning

confidence: 99%