TY - JOUR
T1 - Be-10 Dating of Ice-Marginal Moraines in the Khumbu Valley, Nepal, Central Himalaya, Reveals the Response of Monsoon-Influenced Glaciers to Holocene Climate Change
AU - Hornsey, Josephine
AU - Rowan, Ann V.
AU - Kirkbride, Martin P.
AU - Livingstone, Stephen J.
AU - Fabel, Derek
AU - Rodes, Angel
AU - Quincey, Duncan J.
AU - Hubbard, Bryn
AU - Jomelli, Vincent
N1 - Funding Information:
J. Hornsey was supported by a Natural Environment Research Council (NERC) ACCE DTP studentship (NE/L002450/1). A. V. Rowan was supported by a Royal Society Dorothy Hodgkin Research Fellowship (DHF/R1/201113). Fieldwork was supported by the “EverDrill” NERC Grant awarded to the Universities of Leeds and Sheffield (NE/P00265X) and Aberystwyth University (NE/P002021). Be‐10 measurements made at SUERC were supported by NERC through a Cosmogenic Isotope Analysis Facility grant (CIAF/9190/1018). M. P. Kirkbride acknowledges the support of the Mount Everest Foundation and the Quaternary Research Association. The authors thank Himalayan Research Expeditions, Kathmandu, for their support and guiding during fieldwork. All rock samples were collected with the permission of the Sagarmatha National Park authority and exported from Nepal with the permission of the Government of Nepal through the Department of National Parks and Wildlife Conservation. The authors thank Benjamin Lehmann, Aaron Putnam and Da Huo for their constructive and thoughtful comments that improved the presentation of this work.
Funding Information:
J. Hornsey was supported by a Natural Environment Research Council (NERC) ACCE DTP studentship (NE/L002450/1). A. V. Rowan was supported by a Royal Society Dorothy Hodgkin Research Fellowship (DHF/R1/201113). Fieldwork was supported by the “EverDrill” NERC Grant awarded to the Universities of Leeds and Sheffield (NE/P00265X) and Aberystwyth University (NE/P002021). Be-10 measurements made at SUERC were supported by NERC through a Cosmogenic Isotope Analysis Facility grant (CIAF/9190/1018). M. P. Kirkbride acknowledges the support of the Mount Everest Foundation and the Quaternary Research Association. The authors thank Himalayan Research Expeditions, Kathmandu, for their support and guiding during fieldwork. All rock samples were collected with the permission of the Sagarmatha National Park authority and exported from Nepal with the permission of the Government of Nepal through the Department of National Parks and Wildlife Conservation. The authors thank Benjamin Lehmann, Aaron Putnam and Da Huo for their constructive and thoughtful comments that improved the presentation of this work.
Publisher Copyright:
© 2022. The Authors.
PY - 2022/8
Y1 - 2022/8
N2 - The dynamic response of large mountain glaciers to climatic forcing operates over timescales of several centuries and therefore understanding how these glaciers change requires observations of their behavior through the Holocene. We used Be-10 exposure-age dating and geomorphological mapping to constrain the evolution of glaciers in the Khumbu Valley in the Everest region of Nepal. Khumbu and Lobuche Glaciers are surrounded by high-relief lateral and terminal moraines from which seven glacial stages were identified and dated to 7.4 ± 0.2, 5.0 ± 0.3, 3.9 ± 0.1, 2.8 ± 0.2, 1.3 ± 0.1, 0.9 ± 0.02, and 0.6 ± 0.16 ka. These stages correlate to each of the seven latest Holocene regional glacial stages identified across the monsoon-influenced Himalaya, demonstrating that a coherent record of high elevation terrestrial palaeoclimate change can be extracted from dynamic mountain landscapes. The time-constrained moraine complex represents a catchment-wide denudation rate of 0.8–1.4 mm a−1 over the last 8 kyr. The geometry of the ablation area of Khumbu Glacier changed around 4 ka from a broad, shallow ice tongue to become narrower and thicker as restricted by the topographic barrier of the terminal moraine complex.
AB - The dynamic response of large mountain glaciers to climatic forcing operates over timescales of several centuries and therefore understanding how these glaciers change requires observations of their behavior through the Holocene. We used Be-10 exposure-age dating and geomorphological mapping to constrain the evolution of glaciers in the Khumbu Valley in the Everest region of Nepal. Khumbu and Lobuche Glaciers are surrounded by high-relief lateral and terminal moraines from which seven glacial stages were identified and dated to 7.4 ± 0.2, 5.0 ± 0.3, 3.9 ± 0.1, 2.8 ± 0.2, 1.3 ± 0.1, 0.9 ± 0.02, and 0.6 ± 0.16 ka. These stages correlate to each of the seven latest Holocene regional glacial stages identified across the monsoon-influenced Himalaya, demonstrating that a coherent record of high elevation terrestrial palaeoclimate change can be extracted from dynamic mountain landscapes. The time-constrained moraine complex represents a catchment-wide denudation rate of 0.8–1.4 mm a−1 over the last 8 kyr. The geometry of the ablation area of Khumbu Glacier changed around 4 ka from a broad, shallow ice tongue to become narrower and thicker as restricted by the topographic barrier of the terminal moraine complex.
KW - Be-10
KW - glacier change
KW - Himalaya
KW - Holocene
KW - moraines
KW - palaeoclimate
UR - http://www.scopus.com/inward/record.url?scp=85136846768&partnerID=8YFLogxK
U2 - 10.1029/2022JF006645
DO - 10.1029/2022JF006645
M3 - Article
AN - SCOPUS:85136846768
SN - 2169-9003
VL - 127
JO - Journal of Geophysical Research: Earth Surface
JF - Journal of Geophysical Research: Earth Surface
IS - 8
M1 - e2022JF006645
ER -
