CAJ | 학술논문

黑龙江杂岩主要由蓝闪石片岩构成,蓝闪石片岩主要包括绿帘石、绿泥石、钠长石、钠质角闪石、多硅白云母和石英以及为数不多的榍石、钛铁矿和黑硬绿泥石.其中,钠质角闪石包括蓝闪石和镁质钠闪石.变质条件的压力(P)温度(T)评价条件为400～425 ℃和0.69～0.86 MPa,对应岩相为绿帘蓝闪石片岩相.黑龙江杂岩蓝闪石片岩的地球化学研究表明,其原岩是可与洋岛型(OIB)玄武岩和一些洋中脊型(E-MORB)玄武岩相对比的大洋玄武岩,这说明黑龙江杂岩蓝闪石片岩的玄武岩原岩是在海底山或者在大洋隆起条件下由富集源形成的;具有洋岛型玄武岩地球化学特征的变质玄武岩以及富锰的变质燧石、大理石、变质硬砂岩和蛇绿岩鳞片的加入证明黑龙江杂岩是消减-增生杂岩,它含有变形洋壳的碎块和在被改造的前震旦纪佳木斯岩体西边缘上形成于侏罗纪的增生楔岩石;黑龙江杂岩在原岩成分上可与活动大陆边缘许多增生的杂岩相当.
흑룡강잡암주요유람섬석편암구성,람섬석편암주요포괄록렴석、록니석、납장석、납질각섬석、다규백운모화석영이급위수불다적설석、태철광화흑경록니석.기중,납질각섬석포괄람섬석화미질납섬석.변질조건적압력(P)온도(T)평개조건위400～425 ℃화0.69～0.86 MPa,대응암상위록렴람섬석편암상.흑룡강잡암람섬석편암적지구화학연구표명,기원암시가여양도형(OIB)현무암화일사양중척형(E-MORB)현무암상대비적대양현무암,저설명흑룡강잡암람섬석편암적현무암원암시재해저산혹자재대양륭기조건하유부집원형성적;구유양도형현무암지구화학특정적변질현무암이급부맹적변질수석、대리석、변질경사암화사록암린편적가입증명흑룡강잡암시소감-증생잡암,타함유변형양각적쇄괴화재피개조적전진단기가목사암체서변연상형성우주라기적증생설암석;흑룡강잡암재원암성분상가여활동대륙변연허다증생적잡암상당.
The Heilongjiang Complex contains blueschists composing of epidote, chlorite, albite, sodic amphibole, phengite, quartz, with minor amounts of titanite, ilmenite, and stilpnomelane. Sodic amphiboles are glaucophane to magnesioriebeckite. The Pressure(P)-Temperature(T) metamorphic conditions are estimated to be 400-425 'C and 0. 69-0. 86 MPa, which correspond to epidote-blueschist facies. Geochemical study of blueschists from the Heilongjiang Complex showed that their protoliths were oceanic basalts, which were comparable with oceanic island basalt(OIB) or some types of basalts from plume-influenced regions(E-MORB). This suggests the formation of basalt protolith of the Heilongjiang blueschists from enriched source in seamount or oceanic uplift setting. The presence of metabasalts with geochemical features typical of ocean island basalts, as well as Mn-rich metacherts, marbles, metagraywackes and ophiolite slices, indicates that the Heilongjiang Complex is a subduction-accretionary complex, containing fragments of deformed oceanic crust and rocks of an accretionary wedge, which was formed at the western part of reworked Pre-Sinian Jiamusi Massif in the Jurassic. The complex is comparable in protolith compositions with many accretionary complexes of active continental margins.