Geochemistry of Marine Carbonates from Hole 1394, off the coast of Montserrat, IODP Expedition-340; Implications on provenance, paleoenvironment and Lesser Antilles arc migration
| Autor: | A. K. Krishna, Ch. Narshimha, K.S.V. Subramanyam, C. Manikyamba, Parijat Roy, Vysetti Balaram, S. S. Sawant |
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| Přispěvatelé: | Council of Scientific and Industrial Research [India] (CSIR) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Total organic carbon
Provenance 010504 meteorology & atmospheric sciences Rare-earth element Terrigenous sediment Geochemistry engineering.material IODP-Expedition 340 ''Lesser Antilles Volcanism and Landslides'' Science Party IODP Expedition-340 010502 geochemistry & geophysics 01 natural sciences chemistry.chemical_compound Montserrat Volcanic Island chemistry Total inorganic carbon Marine carbonates engineering Lesser Antilles Arc Carbonate Plagioclase [CHIM]Chemical Sciences Seawater 14. Life underwater Rare earth elements Geology 0105 earth and related environmental sciences |
| Zdroj: | Dynamics of the Earth System: Evolution, Processes and Interactions Dynamics of the Earth System: Evolution, Processes and Interactions, Springer International Publishing, pp.101-140, 2020, Society of Earth Scientists Series, ⟨10.1007/978-3-030-40659-2_6⟩ Dynamics of the Earth System: Evolution, Processes and Interactions ISBN: 9783030406585 |
| DOI: | 10.1007/978-3-030-40659-2_6⟩ |
| Popis: | International audience; The marine carbonate sediment samples are subsampled and collected from various cores spanning from top depths 11.67 meters (core depth below sea floor; CSF) and 11.45 meters (CSF) up to the depth of 168.57 meters (CSF) respectively of U1394 A and B holes drilled to south east of Montserrat Volcanic Island during IODP Expedition 340 These thin horizons are characterised for major, minor, trace and rare earth elements, total carbon to decipher their mode of origin, provenance, implications on paleo-environment. The carbonate sediments show variation in major oxide contents in SiO2 (11.4-35.5 wt.%), CaO (22.4-44.7 wt.%), CaCO3 (3.6-76.6 wt.%), Fe2O3T (1.1-6.0 wt.%), MgO (2.9-4.0 wt.%) with very low K2O, TiO2 and P2O5 contents. Their Mg/Ca, reciprocals (Ca/Mg) and Sr/Ca ratios classify these sediments as dolomitic limestones. These sediments depict very low total organic carbon (TOC) contents compared to total inorganic carbon (Tic) indicating their lithgenic origin. The PAAS normalised rare earth element and yttrium (REY) distribution patterns show slightly depleted LREE abundances relative to HREE with (La/Yb)SN range between 0.3-0.7 indicating low degree of fractionation with varying ∑REE contents (35-105 ppm). Subchrondritic to superchondritic Y/Ho (25.7-31.6), Ce/Ce* (0.2-0.5) and Pr/Pr* (1.0-1.3) indicate low magnitude negative anomalies, slight negative to positive anomalies Eu/Eu* (0.9-1.6) point towards the minimal terrigenous input, varied nature of sediments and plagioclase addition. The studied sediments mimic the seawater REY distribution patterns indicating REY are sourced from the seawater. The major, minor, immobile element ratios and redox sensitive element proxies indicate that the studied carbonate sediments are derived from an intermediate to felsic source. These sediments deposited in a low saline, oxygen rich open ocean shallow water environment akin to an active continent margin affinity. It can also be stated that later to their dissolution in extinct arc zones (between the old and young arc) led to the re-deposition in favourable sites in the marine sediment column during middle Miocene period or later due to the submarine slope failures and debri avalanches. |
| Databáze: | OpenAIRE |
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