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Title: Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia

Abstract

Production, transport and deposition of mineral dust have significant impacts on different components of the Earth systems through time and space. In modern times, dust plumes are associated with their source region(s) using satellite and land-based measurements and trajectory analysis of air masses through time. Reconstruction of past changes in the sources of mineral dust as related to changes in climate, however, must rely on the knowledge of the geochemical and mineralogical composition of modern and paleo-dust, and that of their potential source origins. In this contribution, we present a 13,000-yr record of variations in radiogenic Sr–Nd–Hf isotopes and Rare Earth Element (REE) anomalies as well as dust grain size from an ombrotrophic (rain fed) peat core in NW Iran as proxies of past changes in the sources of dust over the interior of West Asia. Our data shows that although the grain size of dust varies in a narrow range through the entire record, the geochemical fingerprint of dust particles deposited during the low-flux, early Holocene period (11,700–6,000 yr BP) is distinctly different from aerosols deposited during high dust flux periods of the Younger Dryas and the mid-late Holocene (6,000–present). Our findings indicate that the composition of mineral dustmore » deposited at the study site changed as a function of prevailing atmospheric circulation regimes and land exposure throughout the last deglacial period and the Holocene. Simulations of atmospheric circulation over the region show the Northern Hemisphere Summer Westerly Jet was displaced poleward across the study area during the early Holocene when Northern Hemisphere insolation was higher due to the Earth's orbital configuration. This shift, coupled with lower dust emissions simulated based on greening of the Afro-Asian Dust Belt during the early Holocene likely led to potential sources in Central Asia dominating dust export to West Asia during this period. In contrast, the dominant western and southwest Asian and Eastern African sources have prevailed during the mid-Holocene to modern times.« less

Authors:
ORCiD logo; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1565651
Resource Type:
Journal Article
Journal Name:
Earth and Planetary Science Letters
Additional Journal Information:
Journal Volume: 481; Journal Issue: C; Journal ID: ISSN 0012-821X
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
Geochemistry & Geophysics

Citation Formats

Sharifi, Arash, Murphy, Lisa N., Pourmand, Ali, Clement, Amy C., Canuel, Elizabeth A., Naderi Beni, Abdolmajid, A.K. Lahijani, Hamid, Delanghe, Doriane, and Ahmady-Birgani, Hesam. Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia. United States: N. p., 2018. Web. doi:10.1016/j.epsl.2017.10.001.
Sharifi, Arash, Murphy, Lisa N., Pourmand, Ali, Clement, Amy C., Canuel, Elizabeth A., Naderi Beni, Abdolmajid, A.K. Lahijani, Hamid, Delanghe, Doriane, & Ahmady-Birgani, Hesam. Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia. United States. doi:10.1016/j.epsl.2017.10.001.
Sharifi, Arash, Murphy, Lisa N., Pourmand, Ali, Clement, Amy C., Canuel, Elizabeth A., Naderi Beni, Abdolmajid, A.K. Lahijani, Hamid, Delanghe, Doriane, and Ahmady-Birgani, Hesam. Mon . "Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia". United States. doi:10.1016/j.epsl.2017.10.001.
@article{osti_1565651,
title = {Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia},
author = {Sharifi, Arash and Murphy, Lisa N. and Pourmand, Ali and Clement, Amy C. and Canuel, Elizabeth A. and Naderi Beni, Abdolmajid and A.K. Lahijani, Hamid and Delanghe, Doriane and Ahmady-Birgani, Hesam},
abstractNote = {Production, transport and deposition of mineral dust have significant impacts on different components of the Earth systems through time and space. In modern times, dust plumes are associated with their source region(s) using satellite and land-based measurements and trajectory analysis of air masses through time. Reconstruction of past changes in the sources of mineral dust as related to changes in climate, however, must rely on the knowledge of the geochemical and mineralogical composition of modern and paleo-dust, and that of their potential source origins. In this contribution, we present a 13,000-yr record of variations in radiogenic Sr–Nd–Hf isotopes and Rare Earth Element (REE) anomalies as well as dust grain size from an ombrotrophic (rain fed) peat core in NW Iran as proxies of past changes in the sources of dust over the interior of West Asia. Our data shows that although the grain size of dust varies in a narrow range through the entire record, the geochemical fingerprint of dust particles deposited during the low-flux, early Holocene period (11,700–6,000 yr BP) is distinctly different from aerosols deposited during high dust flux periods of the Younger Dryas and the mid-late Holocene (6,000–present). Our findings indicate that the composition of mineral dust deposited at the study site changed as a function of prevailing atmospheric circulation regimes and land exposure throughout the last deglacial period and the Holocene. Simulations of atmospheric circulation over the region show the Northern Hemisphere Summer Westerly Jet was displaced poleward across the study area during the early Holocene when Northern Hemisphere insolation was higher due to the Earth's orbital configuration. This shift, coupled with lower dust emissions simulated based on greening of the Afro-Asian Dust Belt during the early Holocene likely led to potential sources in Central Asia dominating dust export to West Asia during this period. In contrast, the dominant western and southwest Asian and Eastern African sources have prevailed during the mid-Holocene to modern times.},
doi = {10.1016/j.epsl.2017.10.001},
journal = {Earth and Planetary Science Letters},
issn = {0012-821X},
number = C,
volume = 481,
place = {United States},
year = {2018},
month = {1}
}