Geochronology of the Hannan intrusive complex to adjoin the Qinling orogenand its rapid cooling reason

The geochronological works for the Hannan intrusive complex, cosisting of t he gabbro quartz diorite-plagiogranite bodies, in the north border of the Y angtze craton block, adjoining the Qinling orogen, are reported, because it s age and genesis are of great importance to research of the tectonic evalu tional history for the Qinling orogen and of the rifted processes for the L ate Proterozoic supercontinent Rodinia. A good isochron of t=(837 +/- 26) M a (2 sigma), corresponding to I-Nd=0.51165 +/-2(2 sigma), epsilon (Nd)(t)=1.9, MSWD1.02, was difined by the Nd isotopic analytical results for the 21 whole-rock samples from the varied lithological complex bodies, but for th e Rb-Sr isotopic aralytical data there is no isochron, The Ar-40/Ar-39 plat eau age of the biotite, sorted from plagiogranites, is (796 +/- 20) Ma(2 si gma), and yet for the Rb-Sr isotopic data of the plagiogranite whole-rock s amples (WR) and the sorted biotite (Bio), plagioclase (Plag) and apatite (A pt) mineral samples from the plagiogranite whole-rock samples, an isochron of t=(824.8 +/-3.8) Ma (2 sigma) with I-Sr=0.70393 +/- 14(2 sigma), MSWD2.4 4 is given. The U-Pb isotopic results for the single zircon, sorted from pl agiogranite samples, yielded an upper and a lower intercept ages of similar to 876 Ma and similar to 273 Ma. The Nd isotope data of complex indicate t hat it is probably the products of crystallization differentiation from the magma with epsilon (Nd)>0 when the rapid uplift in 837-800 Ma took place i n the northern border of the Yangtze craton block.