Origin of the Deccan Trap flows at Mahabaleshwar inferred from Nd and Sr isotopic and chemical evidence

Mahoney, John J.; MacDougall, J. D.; Lugmair, G. W.; Murali, A. V.; Das, M. Sankar; Gopalan, K.

doi:10.1016/0012-821x(82)90019-x

Cited by 187 publications

(65 citation statements)

References 30 publications

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“…The major issue in the study of continental basalts is to identify their mantle source (Mahoney et al 1982). The obtained data reflect a contamination of LIL-depleted magmas by two magmatic members; one is undoubtedly the continental crust and the other enriched mantle.…”

Section: Discussionmentioning

confidence: 99%

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

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The paper presents new major and trace element and first Sr-Nd isotope data from selected lavas among the Permian basaltic andesite and basalts of the Hronicum Unit and the dolerite dykes cutting mainly the Pennsylvanian strata. The basic rocks are characterized by small to moderate mg # numbers (30 to 54) and high SiO 2 contents (51-57 wt. %). Low values of TiO 2 (1.07-1.76 wt. %) span the low-Ti basalts. Ti/Y ratios in the dolerite dykes as well as the basaltic andesite and basalt of the 1 st eruption phase are close to the recommended boundary 500 between high-Ti and low-Ti basalts. Ti/Y value from the 2 nd eruption phase basalt is higher and inclined to the high-Ti basalts. In spite of this fact, in all studied Hronicum basic rocks Fe 2 O 3 * is lower than 12 wt. % and Nb/La ratios (0.3-0.6) are low, which is more characteristic of low-Ti basalts. The basic rocks are characterized by Nb/La ratios (0.56 to 0.33), and negative correlations between Nb/La and SiO 2 , which point to crustal assimilation and fraction crystallization. The intercept for Sr evolution lines of the 1 st intrusive phase basalt is closest to the expected extrusions age (about 290 Ma) with an initial 87 Sr/ 86 Sr ratio of about 0.7054. Small differences in calculated values I Sr document a partial Sr isotopic heterogeneity source (0.70435-0.70566), or possible contamination of the original magma by crustal material. For Nd analyses of the three samples, the calculated values εCHUR (285 Ma) are positive (from 1.75 to 3.97) for all samples with only subtle variation. Chemical and isotopic data permit us to assume that the parental magma for the Hronicum basic rocks was generated from an enriched heterogeneous source in the subcontinental lithospheric mantle.

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Section: Discussionmentioning

confidence: 99%

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Vozár¹,

Spišiak²,

Vozárová³

et al. 2015

Geologica Carpathica

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“…The lower most, Salher Formation, is conspicuously dominant in the lower reaches and mainly consists of compound flows. The overlying thick pile of largely compound flows known as Lower Ratnagarh Formation and the next overlying group of compound flows exposed is called as Upper Ratnagarh Formation [15]- [17].…”

Section: Location and Geology Of The Areamentioning

confidence: 99%

Slope Stability Assessment of Saptashrungi Gad Temple, Vani, Nashik, Maharashtra, India—A Numerical Approach

Ansari¹,

Ahmad²,

Singh³

et al. 2016

WJET

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The worship places in India are usually situated in and around the hilly regions and/or mountainous area and a number of devotees used to visit the holy places in every area for worship. The stability slopes upon which these worship places are located in the hilly and mountainous region are always a major concern. Moreover, heavy precipitation, weathering conditions, seismic disturbances and human activities could cause problem to the stability of such slopes. The effect of slope instability could cause delay in traffic, loss of life of the devotees at pilgrim sites and the loss of the properties. The Saptashrungi gad temple (SGT) situated on basaltic hills belongs to Deccan volcanic and is one among the 51 Shakti Peeths and the most holy place for pilgrims. In this research, the slope stability analysis at SGT hill is assessed using Phase 2, a finite element program along the two parikrama paths: Parikrama Path 1 (or the Badi Parikrama Path "BPP"), and Parikrama Path 2 (or the Chhoti Parikrama Path "CPP"). On the basis of extensive field work, topographic survey, complex geology, orientations of joint sets, hill slope faces and geotechnical conditions, the study area has been divided into eight zones (Zone#01 to Zone#08), and eighteen topographic profiles (AA′ to RR′) are taken from these eight zones for detailed slope stability analysis. The analysis helps to identify the potentially vulnerable slope and zone of instability.

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“…Neodymium isotope ratios of basalts from Mau- Dupre, unpubl. data, 1984); Rodrigues (data from Baxter et al, 1985); Mauritius (data from Mahoney et al, 1989); the Ambenali, Mahabaleshwar, and Poladpur formations of the Deccan flood basalts from southwestern India (data from Mahoney et al, 1982;Lightfoot, 1985;Lightfoot and Hawkesworth, 1988); and several other islands from the Indian and South Atlantic oceans (White and Hofmann, 1982;Dupre and Allegre, 1983;Hart, 1988;Palacz and Saunders, 1986; W. M. White and B. Dupre, unpubl. data, 1984).…”

Section: Temporal Variations In Reunion Mantle Plume Magmasmentioning

confidence: 99%

“…For example, Lightfoot and Hawkesworth (1988) attribute the low 206 Pb/ 204 Pb ratios in Mahabaleshwar and Ambenali magmas to a continental lithospheric component. Mahoney et al (1982) also argued that at least two assimilates were required: an upper crustal "granitic" component, and a lower crustal "granulitic component" or an "incompatible-elementenriched mantle" component.…”

Section: Relationship Of Leg 115 and Deccan Basaltsmentioning

confidence: 99%

Isotope Geochemistry of Leg 115 Basalts and Inferences on the History of the Réunion Mantle Plume

White¹,

Cheatham²,

Duncan³

1990

Proceedings of the Ocean Drilling Program

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Strontium, neodymium, and lead isotope ratios are reported for 13 Leg 115 basalts as well as 3 basalts from Texaco drill hole SM-1 on the Mascarene Plateau. Pb ratios, typical of Indian Ocean mid-ocean ridge (MORB) and oceanic-island basalts (OIB). Isotopic compositions of Leg 115 basalts generally fall between fields for MORB and Reunion Island basalts, consistent with the conclusion drawn from geochronological studies that Deccan flood basalt volcanism, the Chagos-Laccadive Ridge, and the Mascarene Plateau are all products of the Reunion mantle plume. Isotopic compositions of magmas produced by this plume have varied systematically with time in the direction of less "depleted," less MORB-like isotopic signatures. This compositional change has been accompanied by a decrease in eruption rate. We interpret Deccan volcanism as the voluminous beginning of the plume. Reduced entrainment of asthenosphere following melting of the plume head resulted in less MORB-like isotope ratios in magmas and a decrease in eruptive activity with time.

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Origin of the Deccan Trap flows at Mahabaleshwar inferred from Nd and Sr isotopic and chemical evidence

Cited by 187 publications

References 30 publications

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

Slope Stability Assessment of Saptashrungi Gad Temple, Vani, Nashik, Maharashtra, India—A Numerical Approach

Isotope Geochemistry of Leg 115 Basalts and Inferences on the History of the Réunion Mantle Plume

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