Lithospheric temperature estimates from seismic attenuation across range fronts in southern and central Eurasia

Seismic attenuation (1/Q) changes abruptly between the stable Eurasian crat on and adjacent mountain belts associated with the Alpine-Himalayan collisi on. New attenuation measurements on local body and coda waves provide quant itative constraints on this contrast, near the Caucasus, Kopet Dagh, and Ti en Shan mountains. The 1/Q estimates from all range fronts are similar, the mountains being two to three times more attenuative than adjacent stable p latforms. These 1/Q variations are a reasonable proxy for temperature varia tions, and reveal crustal heating on the order of 100 degrees C but probabl y not melting beneath the mountain ranges. Attenuation (1/Q) is high wherev er high topography is seen, implying that active mountains are typically ho t. Hence, processes that generate or transport heat dominate advective cool ing due to lithospheric thickening, even over the 10-20 m.y. lifetimes of t hese young mountain belts.