The extent, timing and palaeoclimatic significance of Late-glacial and Holocene snowpatches and glaciers in the Marrakech High Atlas, Morocco

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dc.contributor.authorBell, BAen_AU
dc.contributor.authorHughes, PDen_AU
dc.contributor.authorFletcher, WJen_AU
dc.contributor.authorBraithwaite, RJen_AU
dc.contributor.authorCornelissen, HLen_AU
dc.contributor.authorFink, Den_AU
dc.contributor.authorRhoujjati, Aen_AU
dc.date.accessioned2023-03-30T21:39:23Zen_AU
dc.date.available2023-03-30T21:39:23Zen_AU
dc.date.issued2021-03-19en_AU
dc.date.statistics2023-04-28en_AU
dc.description.abstractPleistocene glaciers were extensive in the Marrakech High Atlas, Morocco. Today, semi-permanent snowpatches survive in topoclimatic settings and there is evidence of niche glaciers as recently as the Little Ice Age and early 20th Century. However, little is known about the state of permanent snow and niche glaciers through the Holocene. One hypothesis is that Little Ice Age glaciers were the largest snow and ice masses since the end of the Late-glacial (Younger Dryas 12.9-11.7 ka). Another possibility is that snow and ice expanded to similar or greater extents at other points in the Holocene. To test these hypotheses, moraine boulders have been sampled on moraine successions in the highest parts of the High Atlas, including moraine successions in front of the névé permanent below the north-facing cliffs of Tazaghart (3890 m a.s.l.), a semi-permanent snowpatch that survives many summers today. This site is bounded by prominent moraine ridges with no soil development and no lichens on surface boulders. Several other high-level sites have been targeted and over 40 samples are currently being processed for 10Be and 36Cl exposure dating. Establishing the relative difference in extent and altitude of Late-glacial and the most recent glaciers in the High Atlas is important for understanding landscape and climate evolution in high mountain areas in the subtropics (31ºN). The dated geomorphological records for late-lying snow and glaciers will be compared to high-resolution 14C dated continuous parasequences from sediment cores from marshes at the Yagour Plateau and Oukaïmeden, both high-level sites in the High Atlas (~2700 m a.s.l.). The proximity of these sites (5-30 km, respectively) from the snowpatch/glacier sites will provide an important independent record of environmental change, spanning the Late-glacial and Holocene. This geomorphological record of former glaciers and snowpatches (moraines and pronival ramparts) is inherently fragmentary in time and the continuous core records from these alpine marshes will provide crucial insights into changing moisture conditions over time, which at these altitudes are closely related to the extent and volume of snowpack. The climates associated with perennial snow cover and niche glaciers, and the associated annual snowpack melt, will be quantified using degree-day modelling. This allows melt rates to be predicted and this can be compared against observed modern climate in the High Atlas region. This involves interrogation of existing meteorological datasets from across the High Atlas and the development of algorithms for interpolation and extrapolation to ungauged higher altitudes. Changes in the nature of the cryosphere through time in the High Atlas Mountains is crucial for understanding human activity and socioeconomic development in the wider region. Today, snowmelt from the High Atlas represents the most important ground water recharge used for a wide variety of purposes. Understanding changes in snow conditions, and as a consequence the behaviour of niche glaciers, in the High Atlas through the Holocene has important implications not only for water supply for humans but also for biological refugia and the evolution of cold-adapted flora and fauna.en_AU
dc.identifier.citationBell, B., Hughes, P., Fletcher, W., Braithwaite, R., Cornelissen, H., Fink, D., & Rhoujjati, A. (2021). The extent, timing and palaeoclimatic significance of Late-glacial and Holocene snowpatches and glaciers in the Marrakech High Atlas, Morocco. Paper presented to the EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7706. Retrieved from: https://doi.org/10.5194/egusphere-egu21-7706en_AU
dc.identifier.conferenceenddate30 April 2021en_AU
dc.identifier.conferencenameEGU General Assembly 2021en_AU
dc.identifier.conferenceplaceOnlineen_AU
dc.identifier.conferencestartdate19 April 2021en_AU
dc.identifier.otherEGU21-7706en_AU
dc.identifier.urihttps://doi.org/10.5194/egusphere-egu21-7706en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/14758en_AU
dc.language.isoenen_AU
dc.publisherCopernicus GmbHen_AU
dc.subjectSnowen_AU
dc.subjectMorainesen_AU
dc.subjectMountainsen_AU
dc.subjectClimatesen_AU
dc.subjectEvolutionen_AU
dc.subjectGeomorphologyen_AU
dc.subjectWateren_AU
dc.subjectHumansen_AU
dc.subjectQuaternary perioden_AU
dc.subjectMoroccoen_AU
dc.titleThe extent, timing and palaeoclimatic significance of Late-glacial and Holocene snowpatches and glaciers in the Marrakech High Atlas, Moroccoen_AU
dc.typeConference Paperen_AU
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