کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5770103 1413272 2017 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Anthropogenic trigger for Late Holocene soil erosion in the Jebel Toubkal, High Atlas, Morocco
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Anthropogenic trigger for Late Holocene soil erosion in the Jebel Toubkal, High Atlas, Morocco
چکیده انگلیسی


- Investigation of an infilled moraine basin in the Jebel Toubkal, High Atlas
- New data on sedimentology, organic microfossils and radiocarbon dating
- Evidence for hillslope erosion after 430-640 AD
- Destruction of tree cover, burning and grazing pressure implicated

The Assif n'Imserdane valley, located in the Jebel Toubkal area of the High Atlas, Morocco, is a highly dynamic geomorphological setting. The valley was glaciated during the Late Pleistocene, and subsequently experienced a catastrophic rock avalanche leading to the formation of one of the largest mass movement landforms in North Africa. Recent research (Hughes et al., GSA Bulletin 126: 1093-1104) has dated the formation of the rock avalanche to the mid-Holocene at 4.5 ± 0.5 ka. In this paper, we examine the sedimentological (organic matter content, magnetic susceptibility, particle size and XRF) and palaeoecological (pollen and spores, non-pollen palynomorphs (NPPs), microcharcoal and conifer tracheid fragments) record of a small infilled basin located adjacent to a Late Pleistocene moraine and close to the rock avalanche in the Arroumd sector. The deposits, primarily fine-grained and minerogenic with a low concentration of organic microfossils including pollen, coprophilous ascospores, wood and charcoal microfragments, are enriched in fine silts and ferrimagnetic minerals, consistent with erosional sources from surrounding slope soils. Three radiocarbon dates from the deposit indicate that the infill event occurred during the first millennium AD (after 430-640 AD). As such, the deposits point to a phase of slope instability and erosion that is not linked to either deglaciation processes or to the mid-Holocene rock avalanche. Instead, the nature and timing suggest that an anthropogenic trigger of degradation to the natural vegetation cover may be implicated, consistent with an increasing scale and intensity of pastoral activity in the southern High Atlas during the early Islamic period in Morocco. The record casts light on a previously undocumented phase of landscape instability in the dynamic setting of the Assif n'Imserdane valley, and highlights the potential for further exploration of small infilled basins in the High Atlas to illuminate the geoecological history of the region.

272

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: CATENA - Volume 149, Part 3, February 2017, Pages 713-726
نویسندگان
, ,