摘要
综合分析前人的热年代学数据发现华山地区自晚白垩世以来至少经历了三次快速隆升阶段,在120～57Ma间华山经历了缓慢隆升过程,约57Ma以来华山开始相对渭河地堑的快速隆升。其中,57～42Ma间、32～22Ma间和约8Ma以来均为相对快速隆升阶段,视隆升速度约为0.18～0.23mm/a;而42～32Ma间和22～8Ma间则为相对缓慢隆升过程,视隆升速度约为0.01mm/a。约57Ma以来华山的隆升-剥蚀量约为8.5km,平均隆升速度约为0.15mm/a;约32Ma以来的总隆升幅度约为4.5～5.1km,平均视隆升速度约为0.14～0.16mm/a。晚中生代以来华山的隆升过程实际上反映的是东秦岭的隆升过程,与区域地貌结构和周缘断陷盆地的演化过程有密切的成因联系,它表明东秦岭地区的三级等高峰顶面是120～57Ma、42～32Ma和22～8Ma间山脉缓慢隆升-剥蚀的结果,同时反映57～55Ma是渭河盆地开始快速裂陷和秦岭北麓正断层开始强烈活动的时间。
This paper addresses the postcrystallization uplift history of Huashan granite on the basis of low temparature thermochronological technique.We think Huashan must have undergone three phases of alternately rapid uplift and slow uplift according to the results of low temperature thermochronology and other geological evidence.The slow uplift happened during 120-57 Ma,42-32 Ma and 22-8 Ma,with surface uplift rate,approximately 0.01 mm/a.The rapid uplift occurred during 57-42 Ma,32-22 Ma and 8-0 Ma with uplift rate approximately 0.18-0.23 mm/a.The geothermal gradient, 35°C/km,the region mean temperature is 10°C.So some 8.5 km of uplift are estimated and the mean rate of uplift is about 0.15 mm/a since about 57 Ma in Huashan area.While some 4.5-5.1 km of uplift are estimated since about 32 Ma and the mean rate of uplift is about 0.14-0.16 mm/a.The three uplift stages of Huashan area accord with isoaltitude peak top surfaces series of east Qinling and the depositional unconformity of Weihe Basin.Therefore,the uplift history in Huashan area indicates that the peak top surfaces of east Qinling were formed respectively during 120-57 Ma,42-32 Ma and 22-8 Ma from old to new,and the rapid rift of Weihe basin began at about 57 Ma.
出处
《地质科技情报》
CAS
CSCD
北大核心
2003年第3期27-32,共6页
Geological Science and Technology Information
基金
国家攀登项目(95-专-05
95-预-40)
国家自然科学基金资助项目(49973018)
