Thermochronologic constraints on uplifting events since the early cretaceous in the north margin of the Luxi rise, eastern China

Abstract

Two 40Ar/39Ar ages and six fission track ages from monzonite and the Jurassic-Cretaceous rocks provide new geochronologic constraints on the timing of uplifting events in the north margin of the Luxi (鲁西) rise, eastern China. 40Ar/39Ar age 111.1±2.4 and 111.2±2.5 Ma of biotite and K-feldspar sampled from the monzonite may record the cooling age at 300 and 150–300 °C, respectively. Fission track ages of zircon and apatite from the monzonite changing from 75±7 to 40±3 Ma record the cooling age at 250 and 120 °C, respectively. The apatite from the Jurassic-Cretaceous sandstone and volcanic rocks yielded a different T-t path. The results indicate that there are two phases 111-46.9 and 13.4 (6.5)-0 Ma of rapid uplifting happened to the north margin of the Luxi rise; the first one is a tilted uplift from north to south in Zibo (淄博) during 111-46.9 Ma and in the south in Mengshan (蒙山) during 70-40 Ma; the second one is a tilted uplift from south to north in Mengshan during 32-20 Ma, and in turn in Taishan (泰山) and Zibo during 23-20 and 13.4-0 or 6.5-0 Ma, respectively. The aging coincidence between magmatism and tectonic uplifting implies there are two phases of uplifting induced by large scale extension and lithospheric thinning.