Most rocks in the range are crystalline, with few areas with sedimentary rock. As such, the mountains are massifs, cut by narrow valleys. Limestone is found only in a few places. Erosion has formed several very prominent platforms, such as the Borăscu platform. Glaciers were present during the ice ages, leaving glacial calderas and small glacial lakes, such as the Bistra Lake.
Climate
Because of the Western climatic influences, the amount of rainfall in the Țarcu Mountains is quite high. Snow may fall at altitudes above 1500 metres at any time in the year, while the snowpack usually lasts from October or November until June or even July in the glacial calderas of the highest peaks.
Important peaks
Vârful Țarcu, 2190 metres, has a weather station on its top.
Vârful Pietrii, 2192 metres, dominating the Bistra Lake.