“…The Palaeoproterozoic Jhazpur Group (NW Indian craton) is considered to be correlative with the Aravalli Super group (Sinha Roy et al 1998;Malhotra and Pandit 2000). The lower Dolomite unit of this Group have negative to near 0 d 13 C values (-4.8 to ?0.9% V-PDB) and negative d 18 O values (-9.5 to -3.8% V-PDB) (Pandit et al 2003). These values are consistent with the d 13 C and d 18 O values obtained from the vempalle carbonates proving a significant correlation between these two units.…”
Section: Comparison With Other Proterozoic Marine Carbonates Of Indiasupporting
confidence: 88%
“…Carbonate strata younger than *1,200 Ma are characterized by significantly higher d 13 C values ranging between ?3.5 ± 1.0% (Bartley et al 2007). To date mechanism proposed by different workers for these C-isotopic shifts in earth's history remain highly debated (Pandit et al 2003(Pandit et al , 2009 and references therein; Melezhik et al 1999). Therefore, there is a wide scope to work on stable isotope geochemistry on Proterozoic marine carbonates to throw light on Proterozoic ocean-atmosphere system, palaeoclimate and geobiology.…”
The marine stromatolitic dolomites of Palaeoproterozoic Vempalle Formation, of Cuddapah Basin, South India show significantly depleted d 18 O (-8.19 to -18.25%) and d 13 C (-0.03 to -5.74) values and are consistent with the global Proterozoic data. A comparison of the stable isotope values from major localities of Proterozoic Basins of India has also been attempted in this study. Significantly depleted d 18 O values of Vempalle carbonate samples could not be considered to be postdepositional modifications as there exists an inverse correlation relationship between C and O isotopic values. The Vempalle stromatolitic dolomite is likely to be precipitated in equilibrium with marine waters significantly depleted in oxygen isotopes (-10 to -15% SMOW) with respect to modern sea water. The negative d 13 C values of the Vempalle carbonates are likely to be interpreted at the backdrop of global ''icehouse'' as there is an indication of dropstone-like features in the lower part of the Vempalle Formation just 2 km, southwest of the study area.
“…The Palaeoproterozoic Jhazpur Group (NW Indian craton) is considered to be correlative with the Aravalli Super group (Sinha Roy et al 1998;Malhotra and Pandit 2000). The lower Dolomite unit of this Group have negative to near 0 d 13 C values (-4.8 to ?0.9% V-PDB) and negative d 18 O values (-9.5 to -3.8% V-PDB) (Pandit et al 2003). These values are consistent with the d 13 C and d 18 O values obtained from the vempalle carbonates proving a significant correlation between these two units.…”
Section: Comparison With Other Proterozoic Marine Carbonates Of Indiasupporting
confidence: 88%
“…Carbonate strata younger than *1,200 Ma are characterized by significantly higher d 13 C values ranging between ?3.5 ± 1.0% (Bartley et al 2007). To date mechanism proposed by different workers for these C-isotopic shifts in earth's history remain highly debated (Pandit et al 2003(Pandit et al , 2009 and references therein; Melezhik et al 1999). Therefore, there is a wide scope to work on stable isotope geochemistry on Proterozoic marine carbonates to throw light on Proterozoic ocean-atmosphere system, palaeoclimate and geobiology.…”
The marine stromatolitic dolomites of Palaeoproterozoic Vempalle Formation, of Cuddapah Basin, South India show significantly depleted d 18 O (-8.19 to -18.25%) and d 13 C (-0.03 to -5.74) values and are consistent with the global Proterozoic data. A comparison of the stable isotope values from major localities of Proterozoic Basins of India has also been attempted in this study. Significantly depleted d 18 O values of Vempalle carbonate samples could not be considered to be postdepositional modifications as there exists an inverse correlation relationship between C and O isotopic values. The Vempalle stromatolitic dolomite is likely to be precipitated in equilibrium with marine waters significantly depleted in oxygen isotopes (-10 to -15% SMOW) with respect to modern sea water. The negative d 13 C values of the Vempalle carbonates are likely to be interpreted at the backdrop of global ''icehouse'' as there is an indication of dropstone-like features in the lower part of the Vempalle Formation just 2 km, southwest of the study area.
“…MnO‐SrO‐FeO wt% plot of carbonate compositions of the studied regional marbles ( n = 57), other marbles, limestones, and dolostones [Data from, (i) limestones ( n = 8), Alvarenga, Santos, Vieira, Lima, & Mancini, 2014; Nagarajan et al, 2008; (ii) cap dolostones ( n = 8), Kennedy, 1996; Mohanty, Barik, Sarangi, & Sarkar, 2014; (iii) marine dolostones ( n = 38), Kah et al, 2001; Kah, 2000; Azmy et al, 2001; (iv) low‐grade dolomitic marble ( n = 10), Pandit et al, 2003; Kuznetsov et al, 2010; and (v) low‐grade calcitic marbles ( n = 4), Kuznetsov et al, 2010]…”
Section: Discussionmentioning
confidence: 99%
“…Marble, a metamorphic rock containing predominant carbonate minerals, can be formed either from regional or contact metamorphism of limestone or dolostone (Bucher & Grapes, 2011). Of these two types, regionally metamorphosed low‐grade marbles often preserve their primary structural, mineralogical, and geochemical characteristics (Kuznetsov et al, 2010; Pandit, Sial, Malhotra, Shekhawat, & Ferreira, 2003). Although, primary textural characteristics of high‐grade regional marbles have been obliterated through metamorphic process, their primary chemical and isotope contents could be inherited as observed in certain terrains (Boulvais, Fourcade, Moine, Gruau, & Cuney, 2000; Melezhik, Huhma, Condon, Fallick, & Whitehouse, 2007).…”
Proterozoic high‐grade marbles cover a significant portion of the Highland Complex (HC) of Sri Lanka. Although many studies on metamorphic silicate rocks of the country have been carried out, marbles, which can be used as a tool to interpret the evolution history of the crust, has been paid little attention. The present study aims to understand the genesis and characteristics of protolith of these marbles by investigating their mineralogy and geochemistry. The studied marbles occur as bands intercalated with pelitic gneisses and quartzites of the HC, indicating the pre‐existing sandstone‐shale‐carbonate sedimentary sequence. Except along the lithological contacts, the studied marbles contain low amounts of silicate minerals (<5%) and are dominated by dolomites (>90%) with minor calcites. Calcites occur as inclusions within dolomites or as fine grains along the grain boundaries of dolomites. Silicate minerals always occur as lensoid or layered aggregations. Dolomites are related to the protolith composition, while most of the calcites are metamorphic products formed due to the reaction of silicate minerals with dolomite. Silicate mineralogical zones suggest the inherited compositional variations of the protolith. Although the marbles have undergone granulite‐grade metamorphism, their trace elemental contents have been well preserved. Concentrations of Fe, Mn, Sr, Na, and K as well as rare earth element (REE) contents of the marbles are comparable to those of marine origin carbonates. Hence, marine dolostone can be proposed as the protolith for Sri Lankan marbles. The distinct mineralogy as well as elevated trace element and REE concentrations of marble in the lithological contact zones are evidenced for prevailed syn‐ to post‐metamorphic fluid activities in the HC. Mineralogical and trace elemental composition of Sri Lankan marbles are correlated well with the marbles from other East‐Gondwanaland crustal units.
“…In the Jahajpur area two parallel ridges of dolomitic limestone occur from Ghevaria (SW) up to Jahajpur (NW) [6, 7]. Figure 1Geology map of the study area [17, 18, 19]…”
Advancement of airborne hyperspectral remote sensing techniques provides subtle variations to identify minerals and to make distinctions between rock formations. These techniques clearly define barren land versus economically viable zones containing ores and minerals. As we know profitable mineral zones are commonly associated with hydrothermal alteration zones, hyperspectral remote sensing techniques have the capability to identify and distinguish between altered, weathered, and clay minerals. In this research work, airborne hyperspectral remote sensing image from AVIRIS-NG is used to identify hydrothermally altered minerals in the Jahajpur region of Bhilwara district, Rajasthan, India. The purpose of this study is the identification of the minerals through spectral features of image spectra in corroboration with field sample spectra and USGS laboratory spectra. The spectral angle mapper (SAM) and Spectral Feature Fitting (SFF) algorithms were used for the mapping of the minerals. This study was conducted to prove the capability of AVIRIS-NG hyperspectral remote sensing data to identify zones of profitable mineral deposits.
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