ABSTRACT

This paper examines the geomorphological evolution of the Criffel–Dalbeattie granitic pluton (CDGP). Research is based on data from Shuttle Radar Topography Mission, Google Earth, Ordnance Survey maps and field measurements. Granitic emplacement into Southern Uplands terrain along Caledonian structural trends took place during the mid-late Devonian. Faulting and subsidence during the late Palaeozoic and Mesozoic preceded assumed differential uplift of the pluton during the early Palaeocene. This led to the development of bidirectional palaeo-surfaces. Structural rather than lithological controls formed the dominant bases for subsequent weathering during the Palaeogene and Neogene. Shallow surface weathering over the CDGP and absence of saprolite imply that weathering episodes may have been relatively short-lived. However, joint enlargement and in situ eroded corestones indicate that earlier weathered features were substantially modified by glacial agencies. Pleistocene glacial events included ice streaming from the NNW which took place over moulded hills. Thinner late-stage ice scoured irregular hill long profiles while divergent ice contributed to basin erosion. Localised resurgent ice streaming was shortlived. After early uplift and palaeo-surface formation, the CDGP hills evolved through phases of granitic weathering and glacial erosion likely over the past 65 Ma since the early Palaeocene.

摘要

本文研究了 Criffel-Dalbeattie 花岗岩岩体 (CDGP) 的地貌演化。研究基于航天飞机雷达地形任务、谷歌地球、军械测量图和现场测量的数据。在泥盆纪中晚期，花岗岩沿加里东构造趋势进入南部高地地形。晚古生代和中生代的断层和沉降先于假设的早古新世岩体的差异隆升。这导致了双向古表面的发展。构造而不是岩性控制形成了古近纪和新近纪随后风化作用的主要基础。CDGP 上的浅表风化和腐泥土的缺失意味着风化事件可能相对较短。然而，节理扩大和原位侵蚀核心石表明早期风化特征已被冰川作用显着改变。更新世冰川事件包括发生在模压山丘上的 NNW 冰流。较薄的晚期冰冲刷了不规则的山长剖面，而发散的冰则导致盆地侵蚀。局部复苏的冰流是短暂的。在早期隆起和古地表形成之后，CDGP 山丘可能经历了自古新世早期以来的过去 65 Ma 的花岗岩风化和冰川侵蚀阶段。较薄的晚期冰冲刷了不规则的山长剖面，而发散的冰则导致盆地侵蚀。局部复苏的冰流是短暂的。在早期隆起和古地表形成之后，CDGP 山丘可能经历了自古新世早期以来的过去 65 Ma 的花岗岩风化和冰川侵蚀阶段。较薄的晚期冰冲刷了不规则的山长剖面，而发散的冰则导致盆地侵蚀。局部复苏的冰流是短暂的。在早期隆起和古地表形成之后，CDGP 山丘可能经历了自古新世早期以来的过去 65 Ma 的花岗岩风化和冰川侵蚀阶段。