Anthropogenic trigger for Late Holocene soil erosion in the Jebel Toubkal, High Atlas, Morocco
Anthropogenic trigger for Late Holocene soil erosion in the Jebel Toubkal, High Atlas, Morocco
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摩洛哥高阿特拉斯山图卜卡勒山晚全新世土壤侵蚀的人为触发因素
DOI：
10.1016/j.catena.2016.03.025
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发表时间：
2017
期刊：
影响因子：
6.2
通讯作者：
P. Hughes
中科院分区：
文献类型：
--
作者：
W. Fletcher;P. Hughes
位于摩洛哥High Atlas的Jebel Toubkal地区的Assif n 'Imserbal山谷是一个高度动态的地貌环境。该山谷在晚更新世期间被冰川化，随后经历了灾难性的岩石雪崩，导致北非最大的群众运动地貌之一的形成。最近的研究（Hughes等人，GSA Bulletin 126：1093-1104）将岩石雪崩的形成时间定在4.5 ± 0.5 ka的全新世中期。在本文中，我们研究了沉积学（有机质含量，磁化率，粒度和XRF）和古生态（花粉和孢子，非花粉palynomorphs（NPPs），微木炭和针叶树管胞片段）记录的一个小填充盆地位于邻近晚更新世冰碛和接近岩石雪崩的Arroumd部门。沉积物，主要是细粒和成矿与低浓度的有机微化石，包括花粉，粪生子囊孢子，木材和木炭微碎片，富含细粉砂和亚铁磁性矿物，符合侵蚀源周围的斜坡土壤。从存款的三个放射性碳测年表明，填充事件发生在公元第一个千年（公元430-640年后）。因此，这些沉积物表明了斜坡不稳定和侵蚀的阶段，该阶段与冰消过程或中全新世岩石雪崩无关。相反，性质和时间表明，人为触发退化的自然植被覆盖可能会牵连，在摩洛哥的早期伊斯兰时期在南部高阿特拉斯的畜牧业活动的规模和强度不断增加的一致。该记录揭示了以前未记录的阶段景观不稳定的动态设置的Assif n 'Imserket山谷，并强调了进一步探索小填充盆地的高阿特拉斯照亮该地区的地质生态历史的潜力。
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.
影响因子：
18.3
作者：
Buentgen, Ulf;Myglan, Vladimir S.;Kirdyanov, Alexander V.
通讯作者：
Kirdyanov, Alexander V.