Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2012 The Indian monsoon affects the livelihood of over one billion people. Despite the importance of climate to s...
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Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/5291 2023-05-15T18:00:45+02:00 Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations Ponton, Camilo Bay of Bengal Arabian Sea 2012-06 application/pdf https://hdl.handle.net/1912/5291 en_US eng Massachusetts Institute of Technology and Woods Hole Oceanographic Institution WHOI Theses https://hdl.handle.net/1912/5291 doi:10.1575/1912/5291 doi:10.1575/1912/5291 Monsoons Paleoclimatology Holocene Pelagia (Ship) Cruise 64PE300 Thesis 2012 ftwhoas https://doi.org/10.1575/1912/5291 2022-05-28T22:58:36Z Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2012 The Indian monsoon affects the livelihood of over one billion people. Despite the importance of climate to society, knowledge of long-term monsoon variability is limited. This thesis provides Holocene records of monsoon variability, using sediment cores from river-dominated margins of the Bay of Bengal (off the Godavari River) and the Arabian Sea (off the Indus River). Carbon isotopes of terrestrial plant leaf waxes (δ13Cwax) preserved in sediment provide integrated and regionally extensive records of flora for both sites. For the Godavari River basin the δ13Cwax record shows a gradual increase in aridity-adapted vegetation from ~4,000 until 1,700 years ago followed by the persistence of aridity-adapted plants to the present. The oxygen isotopic composition of planktonic foraminifera from this site indicates drought-prone conditions began as early as ~3,000 years BP. The aridity record also allowed examination of relationships between hydroclimate and terrestrial carbon discharge to the ocean. Comparison of radiocarbon measurements of sedimentary plant waxes with planktonic foraminifera reveal increasing age offsets starting ~4,000 yrs BP, suggesting that increased aridity slows carbon cycling and/or transport rates. At the second site, a seismic survey of the Indus River subaqueous delta describes the morphology and Holocene sedimentation of the Pakistani shelf and identified suitable coring locations for paleoclimate reconstructions. The δ13Cwax record shows a stable arid climate over the dry regions of the Indus plain and a terrestrial biome dominated by C4 vegetation for the last 6,000 years. As the climate became more arid ~4,000 years, sedentary agriculture took hold in central and south India while the urban Harappan civilization collapsed in the already arid Indus basin. This thesis integrates marine and ... Thesis Planktonic foraminifera Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Indian Woods Hole, MA |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Monsoons Paleoclimatology Holocene Pelagia (Ship) Cruise 64PE300 |
spellingShingle |
Monsoons Paleoclimatology Holocene Pelagia (Ship) Cruise 64PE300 Ponton, Camilo Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
topic_facet |
Monsoons Paleoclimatology Holocene Pelagia (Ship) Cruise 64PE300 |
description |
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2012 The Indian monsoon affects the livelihood of over one billion people. Despite the importance of climate to society, knowledge of long-term monsoon variability is limited. This thesis provides Holocene records of monsoon variability, using sediment cores from river-dominated margins of the Bay of Bengal (off the Godavari River) and the Arabian Sea (off the Indus River). Carbon isotopes of terrestrial plant leaf waxes (δ13Cwax) preserved in sediment provide integrated and regionally extensive records of flora for both sites. For the Godavari River basin the δ13Cwax record shows a gradual increase in aridity-adapted vegetation from ~4,000 until 1,700 years ago followed by the persistence of aridity-adapted plants to the present. The oxygen isotopic composition of planktonic foraminifera from this site indicates drought-prone conditions began as early as ~3,000 years BP. The aridity record also allowed examination of relationships between hydroclimate and terrestrial carbon discharge to the ocean. Comparison of radiocarbon measurements of sedimentary plant waxes with planktonic foraminifera reveal increasing age offsets starting ~4,000 yrs BP, suggesting that increased aridity slows carbon cycling and/or transport rates. At the second site, a seismic survey of the Indus River subaqueous delta describes the morphology and Holocene sedimentation of the Pakistani shelf and identified suitable coring locations for paleoclimate reconstructions. The δ13Cwax record shows a stable arid climate over the dry regions of the Indus plain and a terrestrial biome dominated by C4 vegetation for the last 6,000 years. As the climate became more arid ~4,000 years, sedentary agriculture took hold in central and south India while the urban Harappan civilization collapsed in the already arid Indus basin. This thesis integrates marine and ... |
format |
Thesis |
author |
Ponton, Camilo |
author_facet |
Ponton, Camilo |
author_sort |
Ponton, Camilo |
title |
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
title_short |
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
title_full |
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
title_fullStr |
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
title_full_unstemmed |
Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
title_sort |
aridification of the indian subcontinent during the holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations |
publisher |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution |
publishDate |
2012 |
url |
https://hdl.handle.net/1912/5291 |
op_coverage |
Bay of Bengal Arabian Sea |
geographic |
Indian |
geographic_facet |
Indian |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
doi:10.1575/1912/5291 |
op_relation |
WHOI Theses https://hdl.handle.net/1912/5291 doi:10.1575/1912/5291 |
op_doi |
https://doi.org/10.1575/1912/5291 |
op_publisher_place |
Woods Hole, MA |
_version_ |
1766169973397389312 |