Outcrops of Kurram and North Waziristan Agencies (Pakistan): Implications from Structural Modeling

In the article, our research of the tectono-stratigraphic imprints of the Indian–Asian plates collision in the outcrops of Kurram and North Waziristan agencies in Pakistan with the help of detailed mapping and subsurface modeling, is presented. Three tectonic domains have been identified in the research based on the stratigraphic mismatch including the Nappe Domain, the allochthonous Indian Plate margin (Orakzai Ranges), and the autochthonous Indian Plate margin (Kohat Basin). In our work we focused on establishing the sequence of tectonic events based on the emplacement of the Nappe Domain eastward on top of the other two domains. The rocks from each domain have been measured and logged to determine their stratigraphic differences. Nappe Domain consists of Jurassic and Cretaceous sequence of sedimentary mélange rocks which are intensely folded and faulted and emplaced on the other two domains. These mélange rocks are emplaced on the Eocene shales of Kohat Basin in the southern part of the research area, while the same mélange rocks overlie the Paleocene carbonates in the Orakzai Ranges. This variable emplacement of the mélange sequence signifies that the research area represents the confluence of tectonically distinct blocks which were far apart during the post-Cretaceous and later, from Late Eocene to Miocene, these blocks were juxtaposed under influence of regional faulting. Our research also proves that the emplacement of the mélange rocks from the west started in post-Paleocene in the northern Orakzai Ranges while the southern Kohat Basin was receiving extensive Eocene deposition which was later overlained by the mélange rocks.