华北中北部晚太古代高压麻粒岩的地质产状及其出露的区域构造背景

The Geological Occurrence, Regional Tectonic Setting andExhumation of Late Archean HighPressure GranuliteWithin the Highgrade Metamorphic Terrains, Northto Central Portion of North China Craton

晋北－冀西北高级变质的灰色片麻岩－花岗质片麻岩杂岩基底内广泛发育晚太古代高压麻粒岩构造透镜体或岩片，几个典型地段的构造填图研究表明，高压麻粒岩主要出露于龙泉关－桑干构造带的东北段，即冀北陆缘活动带与恒山－五台绿岩带之间的高级变质基底内。高压麻粒岩形成与出露的过程中，主要经历４期构造变形：Ｄ１低角度逆掩剪切变形；Ｄ２ＮＷ向伸展作用；Ｄ３区域规模的ＮＮＥ－ＮＥ向褶皱；Ｄ４大规模右旋走滑剪切变形。以上变形明显受区域构造所控制，先后涉及鄂尔多斯和阜平陆块晚太古代构造拼合，太古代末五台裂谷的张开及闭合，以及早元古代冀北陆缘活动带向南俯冲造成的掀斜作用。

A large number of highpressure mafic granulite(HPMG) enclaves or slices are identified within the highgrade TTG to granitic complex basement of northern part of North China Craton(NCC). The detailed structurallithologic mapping and section studies indicate that, HPMGs are predominantly distributed in the northeastern sector of late Archean LongquanguanSanggan tectonic belt(LSTB),roughly trending in NNE direction,which joints Ordos craton(OC) with FupingZanhuang craton(FZC). During its generation and exhumation,HPMG involed at least four major deformation episodes associated with regional tectonic evolution, including: D1 lowerangle thrusting, D2 extensional collapse across NW direction, D3 largescale folding with NENNEtrending hinges, D4 late stage strikesliding shearing. The regional tectonic evolution involved late Archean tectonic colleage between OC and FZC, followed by openning and closure of WutaiHengshan rift, finally early Proterozoic tilting of north margin of NCC to the south, caused by active continental margin belt of North Hebei.