7第六章区域变质作用教程.ppt

第六章 区域变质岩;埋藏变质岩;埋藏变质岩的一般特点;Fig. 25-2. Temperature-pressure diagram showing the generally accepted limits of the various facies used in this text. Winter (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.;2. 埋藏变质作用;埋藏变质作用;区域埋藏变质作用新西兰Otago地区;(3) 埋藏变质作用;Section X-Y shows more detail;区域埋藏变质作用新西兰Otago地区 ;区域埋藏变质作用;造山带也许直接从成岩作用转变到绿泥石或黑云母带 在新西兰低级变质岩带的发育也许反映了火山灰, 杂砂岩和热水活动的极不稳定性, 泥质沉积岩也许直至高级变质时才发生反应.;造山变质岩;造山带的一般特点;双变质带Paired Metamorphic Belts of Japan;Fig. 25-2. Temperature-pressure diagram showing the generally accepted limits of the various facies used in this text. Winter (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.;日本对变质带;外带, 称之为 Sanbagawa带 其具有具有 高压-低温 特征 泥质岩中仅达到石榴石变质带程度 与Ryoke带相比基性(Basic)岩石是十分普遍的, 然而, 在该带中的岩石内发现蓝闪石(glaucophane) 这些岩石通常称为蓝片岩(blueschists);两个带彼此平行产出, 其间为一条大断层所分割 (该断层称之为中线(the Median Line)) Ryoke-Abukuma 带的岩石源于教成熟的火山岛弧(mature volcanic arc) Sanbagawa 带的岩石源于靠大洋一侧的加机楔 (accretionary wedge) , 那儿的物质源于岛弧沉积物和火山岩, 并混有洋壳和大洋沉积物.;日本的对变质带;Miyashiro (1961, 1973) 提出的同时代的变质带: 外带-高P/T 带, 内带: 低 P/T 带, 这种对变质带无论是现今还是较老时期, 在俯冲带中是十分普遍的现象.;双变质带中的特征矿物;Blueschist;;大陆造山变质作用;Fig. 25-2. Temperature-pressure diagram showing the generally accepted limits of the various facies used in this text. Winter (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.;造山变质作用;造山带变质作用;造山带变质作用;在整个造山带中, 变形也许不具有相同样式, 甚至即便是同时代的情况下;Stage II: D2 overprints D1 in forearc (A) in the form of sub-horizontal folding and back-thrusting as pushed against arc crust. Area (C) begins new subduction zone with thrusting and folding migrating toward trench.;Stage III: Accretion deforms whole package. More resistant arc crust gets a D1 event. D2 overprints D1 in forearc (A) and in pluton-emplacement structures in (B). Area (C) in the suture zone gets D3 overprinting D2 recumbent folds on D1 foliations.;造山带可能随着抬升和剥蚀而展现.;主要变质相、特征矿物及岩石;Figure 22-1c. Garnet muscovite schist. Muscovite crystals are visible and silvery, garnets occur as large da