地质论评
地質論評
지질론평
GEOLOGICAL REVIEW
2010年
1期
31-42
,共12页
邓宾%刘树根%刘顺%李智武%司建涛%郭兵%田小兵
鄧賓%劉樹根%劉順%李智武%司建濤%郭兵%田小兵
산빈%류수근%류순%리지무%사건도%곽병%전소병
构造特征%弧形构造%较场弧形带%松潘-甘孜褶皱带
構造特徵%弧形構造%較場弧形帶%鬆潘-甘孜褶皺帶
구조특정%호형구조%교장호형대%송반-감자습추대
structural feature%arc structure%Jiaochang arc belt%Songpan-Garze fold belt
根据详细野外露头特征及显微构造特征将较场弧形带由南向北分为三个变形带:弧顶部、弧核部和弧翼部,不同分带具有明显不同的变形特征.由南向北变形特征由以塑性变形为主过渡为脆性变形为主,变质流体活动喜马拉雅构造期活动强烈,且向北逐渐增强;弧核部以叠瓦状逆冲构造特征分隔弧顶和弧翼部;弧翼部东西两翼变形及变质流体活动特征具有一定差异性.较场弧形带总体体现出多期次南北向挤压-张性应力变形构造特征,叠加北西-北北西向同构造期挤压变质运动,其宏观和微观变形特征与典型"走滑成因"模式弧形构造特征相异,为其大地构造成因机制的解释提出了新的限制条件.
根據詳細野外露頭特徵及顯微構造特徵將較場弧形帶由南嚮北分為三箇變形帶:弧頂部、弧覈部和弧翼部,不同分帶具有明顯不同的變形特徵.由南嚮北變形特徵由以塑性變形為主過渡為脆性變形為主,變質流體活動喜馬拉雅構造期活動彊烈,且嚮北逐漸增彊;弧覈部以疊瓦狀逆遲構造特徵分隔弧頂和弧翼部;弧翼部東西兩翼變形及變質流體活動特徵具有一定差異性.較場弧形帶總體體現齣多期次南北嚮擠壓-張性應力變形構造特徵,疊加北西-北北西嚮同構造期擠壓變質運動,其宏觀和微觀變形特徵與典型"走滑成因"模式弧形構造特徵相異,為其大地構造成因機製的解釋提齣瞭新的限製條件.
근거상세야외로두특정급현미구조특정장교장호형대유남향북분위삼개변형대:호정부、호핵부화호익부,불동분대구유명현불동적변형특정.유남향북변형특정유이소성변형위주과도위취성변형위주,변질류체활동희마랍아구조기활동강렬,차향북축점증강;호핵부이첩와상역충구조특정분격호정화호익부;호익부동서량익변형급변질류체활동특정구유일정차이성.교장호형대총체체현출다기차남북향제압-장성응력변형구조특정,첩가북서-북북서향동구조기제압변질운동,기굉관화미관변형특정여전형"주활성인"모식호형구조특정상이,위기대지구조성인궤제적해석제출료신적한제조건.
The Jiaochang arc belt in Songpan-Garze fold belt is composed with three partitions: arc roof, arc kern, arc limbs,which are different from each others according to the structural feature in field and microstructural feature. The deformational strength becomes shallower from the south to the north, which is mainly ductile strain in south and brittle deformation in north, as well as metamorphic fluid becomes stronger active in Himalayan Epoch according to ESR. Arc kern separates the arc roof from arc limbs, which imbricatly thrusts from south to north, while the later has different feature in activity of metamorphic fluid and deformational strength between western limb and eastern limb. In a word, the Jiaochang arc belt is totally characteristic of multi-phase compressional-tensional movements in north-south trending, overprinted compressional metamorphose in (NW-NNW)-(SE-SSE) trending on orogenic epoch. The macro- and micro- structural feature in Jiaochang arc belt is different from the "strike-slip" mechanism of arc belt, compared with the tectonic setting, it is concluded that the mechanism of the Jiaochang arc belt is owe to combined effect of the Qinling orogen belt and Upper Yangtze block.