地球学报
地毬學報
지구학보
ACTA GEOSCIENTIA SINICA
2014年
4期
510-518
,共9页
付顺%阚瑷珂%肖进%胡瑾%向芳%张腾%李文韬
付順%闞璦珂%肖進%鬍瑾%嚮芳%張騰%李文韜
부순%감애가%초진%호근%향방%장등%리문도
大巴山国家地质公园%构造地貌%构造变形期次%年代学证据
大巴山國傢地質公園%構造地貌%構造變形期次%年代學證據
대파산국가지질공완%구조지모%구조변형기차%년대학증거
Daba Mountain National Geopark%tectonic geomorphology%tectonic deformation periods%chronological evidence
通过野外路线考察,典型地区填图,地质、地形图判读发现,大巴山国家地质公园主要构造地貌景观横向分布呈现由 NE 至 SW 即从造山带向前陆盆地方向逐渐减弱特征;纵向上明显受早期构造格局和岩石类型约束,在区域上呈现 NW-SE 向延展的平行岭谷地貌,山峰和谷地的走向与地质构造线基本一致。通过对主要构造地貌景观构造应力和变形期次判别探讨,确定构造地貌景观形成的构造期次大致为三期,应力主要来自于NE-SW、SE-NW向,反映该区不仅受到NE-SW向的冲断挤压变形作用,还受到SE-NW向的右旋剪切挤压变形作用,推测是由多期受力叠加改造而成。通过ESR及14C定年确定距今12 Ma以来,该区在500 kaBP、278 kaBP、29 kaBP分别出现三次规模较大的快速抬升运动,提供了与其构造景观形成密切相关的新构造运动年代学证据。
通過野外路線攷察,典型地區填圖,地質、地形圖判讀髮現,大巴山國傢地質公園主要構造地貌景觀橫嚮分佈呈現由 NE 至 SW 即從造山帶嚮前陸盆地方嚮逐漸減弱特徵;縱嚮上明顯受早期構造格跼和巖石類型約束,在區域上呈現 NW-SE 嚮延展的平行嶺穀地貌,山峰和穀地的走嚮與地質構造線基本一緻。通過對主要構造地貌景觀構造應力和變形期次判彆探討,確定構造地貌景觀形成的構造期次大緻為三期,應力主要來自于NE-SW、SE-NW嚮,反映該區不僅受到NE-SW嚮的遲斷擠壓變形作用,還受到SE-NW嚮的右鏇剪切擠壓變形作用,推測是由多期受力疊加改造而成。通過ESR及14C定年確定距今12 Ma以來,該區在500 kaBP、278 kaBP、29 kaBP分彆齣現三次規模較大的快速抬升運動,提供瞭與其構造景觀形成密切相關的新構造運動年代學證據。
통과야외로선고찰,전형지구전도,지질、지형도판독발현,대파산국가지질공완주요구조지모경관횡향분포정현유 NE 지 SW 즉종조산대향전륙분지방향축점감약특정;종향상명현수조기구조격국화암석류형약속,재구역상정현 NW-SE 향연전적평행령곡지모,산봉화곡지적주향여지질구조선기본일치。통과대주요구조지모경관구조응력화변형기차판별탐토,학정구조지모경관형성적구조기차대치위삼기,응력주요래자우NE-SW、SE-NW향,반영해구불부수도NE-SW향적충단제압변형작용,환수도SE-NW향적우선전절제압변형작용,추측시유다기수력첩가개조이성。통과ESR급14C정년학정거금12 Ma이래,해구재500 kaBP、278 kaBP、29 kaBP분별출현삼차규모교대적쾌속태승운동,제공료여기구조경관형성밀절상관적신구조운동년대학증거。
Field study, geological mapping of typical areas and interpretation of geological and topographic maps show that the main structural landforms of the area weaken horizontally in NE-SW direction, which is the direction from the orogenic belt to the foreland basin longitudinally constrained obviously by early tectonic framework and rock type. The present parallel ridge valley landforms extend in NW-SE direction. The trend lines of peaks and valleys are basically consistent with the geological structure. Based on the discussion on the tectonic stress and the tectonic deformation stages of the major constructed landscape in the study area, the authors hold that the tectonic structure of the landscape can be roughly divided into three periods, and the stress is mainly in NE-SW and SE-NW directions, suggesting that the study area experienced not only NE-SW trending thrust extrusion deformation but also SE-NW trending dextral shear extrusion deformation, presumably resulting from a multi-phase transformation from the superposition of the force. ESR and 14C dating shows that there have occurred three times of large-scale rapid uplifting since 12 Ma ago, which took place at 500 kaBP, 278 kaBP, and 29 kaBP respectively. The results obtained by the authors provide chronological evidence of neotectonism which was closely related to the formation of structural landscape.