Paläogeographische Entwicklungen an mobilen Schollengrenzen im Westhindukusch (Bande Amir,Zentralafghanistan)

In the region of Bande Amir, located on the southern rim of the Tadschik basin, the Mesozoic section starts with detrital and conglomeratic limestones. These marine deposits of Upper Cretaceous age (Cenomanian-Turonian) disconformably cover a truncated complex of Upper Paleozoic rocks (Permian). After an interval of neritic sedimentation (Santonian, Campanian) the Upper Cretaceous sea (Maastrichtian) regressed from the Central Afghanian High. In the Hindukusch mountains the regression is related to crustal movements and regional uplifts, which hinged on the Herat lineament. Intermontane basins, developed on this mobile zone during mid-Tertiary time, gathered continental debris (Neogene conglomerates; Zohak-Formation) and led to the deposition of lacustrine sediments (Ghulghola-Formation). Orogenetic movements along the colliding edges of crustal blocks were rejuvenated in Plio-Pleistocene time, shifting the focus of deposition to the northwest. The basin was finally captured by the Amu Darja drainage system, leading to the development of canyon-like incisions. During warm periods of the Quaternary, fluviatile erosion in Bande Amir was interrupted at least four times by the retention of water behind large dams of travertine.