Baga Gazriin is an area of granite outcroppings in Middle Gobi province, covering about 300 square kilometres. According to the guidebooks it contains many ancient graves, petroglyphs, khirigsuurs and other monuments, although I didn't see any. Many of the remains date from the time of the Khunnu Empire (better known as the Xiongnu Empire).
The rock formations, which were what we had come here to photograph, are an intrusion of Late Triassic A-type granites: the Baga-Gazriin Chuluu pluton, which was extruded after the Mongol-Okhotsk Ocean closed.