Detailed examination of sediments retained in two north-facing cirques south of Sani Top (latitude 29°30'S; longitude 29°2'E) has been undertaken as a contribution to the Late Quaternary history of highland Lesotho. The sediments are exposed by gullies incised through the deposits. Nine sections are discussed in detail. Inorganic sediments, matrix-supported diamictons and derived orange gravels as well as organic dark clays and peats are present. Eight dated organic samples range in age from 13490BP, currently the oldest organic carbon date from highland Lesotho, to 2310 BP. The sedimentary sequences are interpreted to present a sequence of Late Quaternary events with climatic implications.
A variety of active periglacial microforms have been identified in the vicinity of Tlaeeng Pass (3275 m a.s.l.) in the Lesotho Highlands. These include thufa (both earth and stone‐cored varieties), terracettes, stone polygons and patterned ground. Ground ice within the saturated zone of soil profiles is clearly evident during the winter season, and pebbles perched on needle ice up to 5 cm in length are common. Although possible relict periglacial landforms (such as nivation hollows and protalus ramparts) have been recorded in the area, their identification and, hence, associated climatic inferences is problematic.
The presence of active features clearly indicates present‐day periglacial activity, with the variety of forms resulting from diurnal or seasonal freeze‐thaw cycles. Considering a widely accepted global decrease in temperature during the Quaternary, a severity of temperatures greater than what is experienced under present marginal periglacial conditions can be projected for the Lesotho Highlands. However, past moisture regimes are more difficult to project from present‐day features, and this problem is exacerbated by the general paucity of clearly defined diagnostic relict forms.
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