The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff
(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.
Uncertainty over the identity and age of Toba tephras across peninsular India persists, with
radi... more Uncertainty over the identity and age of Toba tephras across peninsular India persists, with radiometric age dates contradicting earlier compositional data, which have been used to identify this important stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff (YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail. Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits, making the Sagileru Valley one of the few globally identified locations with both ash and archaeology. The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another source of information for understanding Late Pleistocene climate change, depositional environments and hominin occupations of South Asia.
Uncertainty over the identity and age of Toba tephras across peninsular India persists, with
radi... more Uncertainty over the identity and age of Toba tephras across peninsular India persists, with radiometric age dates contradicting earlier compositional data, which have been used to identify this important stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff (YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail. Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits, making the Sagileru Valley one of the few globally identified locations with both ash and archaeology. The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another source of information for understanding Late Pleistocene climate change, depositional environments and hominin occupations of South Asia.
Present study consists geochemical variations and spatial distribution of trace elements (Fe, Mn,... more Present study consists geochemical variations and spatial distribution of trace elements (Fe, Mn, Cr, Co, Cu, Ni, Pb and Zn) of the ocean floor sediments collected along the continental shelf off East coast Tamil Nadu (Chennai to Velanganni) during the 2009 southwest monsoon period. Results indicate sand dominance with abundant calcareous debris and shell fragments. Normalisation of trace metals with Al signifies a geogenic sediment origin. Enrichment factor (EF) of trace metals namely Co, Cr, Cu, Ni, Pb, Mn and Zn exhibit an increasing trend Pb>Cr>Co>Zn>Ni>Cu>Mn indicating high values of Pb, Cr, Co and Zn due to the anthropogenic source. However, contamination factor (CF) and pollution load index (PLI) point less than 1 indicating negligible contamination during the 2009 southwest monsoon period.
The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff
(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.
Uncertainty over the identity and age of Toba tephras across peninsular India persists, with
radi... more Uncertainty over the identity and age of Toba tephras across peninsular India persists, with radiometric age dates contradicting earlier compositional data, which have been used to identify this important stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff (YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail. Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits, making the Sagileru Valley one of the few globally identified locations with both ash and archaeology. The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another source of information for understanding Late Pleistocene climate change, depositional environments and hominin occupations of South Asia.
Uncertainty over the identity and age of Toba tephras across peninsular India persists, with
radi... more Uncertainty over the identity and age of Toba tephras across peninsular India persists, with radiometric age dates contradicting earlier compositional data, which have been used to identify this important stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba... more The Indian subcontinent contains a number of volcanic ash deposits representing the Youngest Toba Tuff (YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail. Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits, making the Sagileru Valley one of the few globally identified locations with both ash and archaeology. The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another source of information for understanding Late Pleistocene climate change, depositional environments and hominin occupations of South Asia.
Present study consists geochemical variations and spatial distribution of trace elements (Fe, Mn,... more Present study consists geochemical variations and spatial distribution of trace elements (Fe, Mn, Cr, Co, Cu, Ni, Pb and Zn) of the ocean floor sediments collected along the continental shelf off East coast Tamil Nadu (Chennai to Velanganni) during the 2009 southwest monsoon period. Results indicate sand dominance with abundant calcareous debris and shell fragments. Normalisation of trace metals with Al signifies a geogenic sediment origin. Enrichment factor (EF) of trace metals namely Co, Cr, Cu, Ni, Pb, Mn and Zn exhibit an increasing trend Pb>Cr>Co>Zn>Ni>Cu>Mn indicating high values of Pb, Cr, Co and Zn due to the anthropogenic source. However, contamination factor (CF) and pollution load index (PLI) point less than 1 indicating negligible contamination during the 2009 southwest monsoon period.
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(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.
radiometric age dates contradicting earlier compositional data, which have been used to identify this important
stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have
been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at
c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four
populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka
Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest
Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D
from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from
YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate
unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
radiometric age dates contradicting earlier compositional data, which have been used to identify this important
stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have
been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at
c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four
populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka
Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest
Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D
from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from
YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate
unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.
(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.
radiometric age dates contradicting earlier compositional data, which have been used to identify this important
stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have
been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at
c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four
populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka
Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest
Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D
from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from
YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate
unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
radiometric age dates contradicting earlier compositional data, which have been used to identify this important
stratigraphic marker as the Youngest Toba Tuff (YTT). To address this issue, new single glass shard analyses have
been performed for samples from Morgaon and Bori (north-western India), which have recently been dated at
c. 800 ka. These, and indeed all Toba tephra samples thus far analysed from India, show the presence of four
populations of glass shards (defined by their Ba/Y ratio), which uniquely identifies them as products of the c. 75-ka
Youngest Toba eruption. Confirmation that the YTT fingerprint is characteristic comes from new analyses of Oldest
Toba Tuff (OTT) glass shards from five sites in the Indian Ocean. These are compositionally identical to Layer D
from the ODP site 758 sediment core (c. 800 ka), and belong to a single, low-Ba population, clearly different from
YTT. These analyses show that there is essentially no reworked OTT material in the YTT eruption, and indicate
unequivocally that all known Toba tephra occurrences in India belong to the c. 75-ka Youngest Toba eruption.
(YTT) volcanic eruption of 75,000 years ago, though relatively few localities have been reported in detail.
Here, we identify tephra deposits in the Sagileru Valley, south India, in association with Palaeolithic
industries. The glass shard and biotite composition of the Sagileru tephra matches that of the YTT from
other terrestrial sites in India and from the Toba caldera, and are distinct from earlier large eruptions
from Toba. Moreover, our survey identified rare associations between lithic artefacts and YTT deposits,
making the Sagileru Valley one of the few globally identified locations with both ash and archaeology.
The identification of ash deposits and stone tool assemblages in the Sagileru Valley provides another
source of information for understanding Late Pleistocene climate change, depositional environments and
hominin occupations of South Asia.