Recognition and application of offlap in endorheic basins: new insights into plateau growth

Accumulating sediments is an inherent attribute of endorheic basins. Overall aggradational stratigraphic architecture can be predicted in endorheic basins, whereas the offlap process can be regarded as an important geological indicator in closed basins. This study theoretically proposes the possible offlap process in endorheic basins, and then explores the actual pattern of the offlap process in the Qaidam basin, the largest endorheic basin in the northern Tibetan Plateau. According to the interpretation of drilling well data and seismic reflection profiles, widespread offlap is identified at all the three boundaries of the Qaidam basin since the late Miocene. The offlap process in endorheic basins is controlled by newborn faults or new isostatic flexures inside the previous basin margin. Interpretation of seismic reflection profiles reflects that the rigid Qaidam block was gradually broken during the India-Eurasian collision and the plateau progressively expanded from pre-existing mountains to basins.

Automated summary

The offlap process in endorheic basins is controlled by newborn faults or new isostatic flexures inside the previous basin margin. Interpretation of seismic reflection profiles of the Qaidam basin reveals that the rigid Qaidam block was gradually broken during the India-Eurasian collision, and the plateau expanded progressively from pre-existing mountains to basins.