地质学报2018，Vol.92Issue(3)：413-436,24.
鲁西地块NW走向断层的活动特征及裂变径迹证据
Characteristics of NW-Trending Faults and Evidence of Fission Track in the Luxi Block
摘要
Abstract
Unlike the North China Craton,the eastern part of which commonly contains NE-trending faults,the Luxi Block hosts one group of well-developed NW-trending faults with obvious geological features,including non-basin-controlled faults and basin-controlled faults.The former is located in the south end of the Luxi Block,with relatively large dipping,and cuts through the Paleozoic and underlying strata.Ductile shear zone occurs in the lower Archaean footwall,with faulting fragments indicating multiple activities.The latter located in the north of the non-basin-controlled faults,except the Mengshan fault,has underdeveloped ductile shearing zone and relatively flat dip,which controls the sedimentation since the Mesozoic.Apatite/zircon fission track analysis show that there existed some differences in activity of the NW-trending faults.The apparent ages of apatite fission track for the samples from hanging wall and footwall are 67±5Ma and 35 ±2Ma,respectively,and the track histogram shows that the samples were not subject to thermal disturbances during the cooling process.The activity time of the faults is restrained using the average track length-age (or banana diagram),single grain peak age,track age spectrum pattern and thermal history inversion simulation.The results show that the non-basin-controlled faults might start activity in the Early Jurassic of about 184Ma,and continued to be active in the Late Cretaceous 80～75Ma and the Cenozoic ca.61Ma and 51～43Ma,and might cease after 43Ma.The basin-controlled faults started active relatively late,probably in Early Cretaceous ca.141Ma,Late Cretaceous 80～75Ma,and was active in about 61Ma,49～42Ma and 36～32Ma during the Cenozoic period.In general,the NW-trending faults developed chronologically from south to north.The non-basin-controlled faults were active early but ceased early;while the basin-controlled faults were active late but ceased later and controlled northward development of the depression.Changing of regional tectonic stress field and strike-slipping of the Tan-Lu fault zone since the Mesozoic was the fundamental causes for the evolution divergence of two types of NW faults.Deep part of the faults was controlled by continent-content collision of North China and Yangtze plates in the Late Triassic,as well as direction and speed change of paleo-Pacific plate subduction.The Indosinian transition from compression to extension,coupled with the sinistral strike-slipping of the Tanlu fault zone,gave the top priority to the development of NW-trending faults near the southern margin of the North China Craton.Because the large dip angle failed to control the development of the basin,the faults extended relatively toward north end,forming basin-controlled faults.After extension in the Early Cretaceous (ca.141Ma),the faults finally gradually took a shape at end of Late Cretaceous (ca.80～ 75Ma) and in the Cenozoic.The generally northward migration of the NW-trending faults suggests that destruction of the North China Craton may initiate in the Early Jurassic or Late Jurassic and delaminated gradually from south to north.关键词
NW走向断层/裂变径迹/演化/中、新生代/鲁西地块Key words
NW-trending faults/evolution/fission track/Meso-Cenozoic/Luxi Block引用本文复制引用
李理,钟大赉,陈霞飞,陈衍..鲁西地块NW走向断层的活动特征及裂变径迹证据[J].地质学报,2018,92(3):413-436,24.基金项目
本文为国家自然科学基金(41672193)资助的成果. （41672193）
