Ms. Cheng Ruilin Department of Earth Sciences, HKU
Qaidam Basin in the north of Tibetan Plateau is one of the highest and the aridest basins in the world. The basin is in a hyperarid, cold, perennially windy and high-ultraviolet condition now. Qaidam Basin has been proposed as a terrestrial analog of Mars because of their similarities in morphology, mineralogy and climate history. One of the intriguing morphological features on Mars, the polygon, is also widely distributed in the playas of the basin. Here, we report the jigsaw puzzle polygons of ~50-100 m across, which uniquely show the jigsaw puzzle shape with interlocked boundaries, comparing to the other reported polygons in this area. The development of jigsaw puzzle polygons together with regular polygons (without the jigsaw puzzle shape) is the result of salt lake evolution during the climatic transition from wet to dry. This study provides implications to the origin of Martian polygons that have raised rims but without cracks on the chloride-rich terrains. They might be formed by the similar formation processes.