A study of deformation phases in slates of Manki Formation, Eastern Attock-Cherat Range, Pakistan
Keywords:
Manki Formation; Attock-Cherat Range; deformation phases; bedding-cleavage angle; slatesAbstract
The Manki slates constitute the bulk of the Manki Formation. Its thickness has variously been quoted to be in excess of several kilometers in various parts of the Attock-Cherat Range. Many workers while characterizing the Manki slates attribute its extra-ordinary thickness to multiple folding events. However, there is no structural evidence to support this assumption.
Pelitic rocks tend to cleave as they shorten (a folding precursor). The Manki slates exhibit exceptionally good exposures of cleavage development. This paper summarize the results of a study that measured, analyzed and interpreted more than 1000 cleavage and associated bedding orientations from with in the Manki slates. Our analysis recognized five distinct phases of folding through D1 to D5 deformation events. As such this paper provides first ever structural evidence to explain the extraordinary thickness of the Manki slates through multiple folding events.
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