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1.
纳米比亚罗辛地区白岗岩型铀矿床产于白岗岩穹窿边部白岗岩与达玛拉基底变质岩内外接触带,以及变质岩片理、褶皱、转折等部位.已有矿床晶质铀矿年龄介于494～508Ma之间,既是D、E两期白岗岩重熔年龄,也是近水平方向韧性剪切变形活动时代.白岗岩型铀矿床铀矿物以晶质铀矿、钍铀矿、钛铀矿为主,晶质铀矿及伴生的锆石、独居石等矿物具有全自形或半自形晶粒状结构、浸染状构造,具有岩浆分异结晶特征.铀铅同位素示踪分析表明铀来自达玛拉基底岩系和A、B、F期白岗岩.含矿的D、E白岗岩是基底变质岩和早期白岗岩部分重熔形成的.以晶质铀矿为主的白岗岩型铀矿床是在达玛拉造山期岩浆形成演化阶段,由结晶分异作用形成铀预富集基础上,在造山期后韧性变形作用下白岗岩再次重熔富集成矿的. 相似文献
2.
东天山区域韧性剪切带特征 总被引：24，自引：2，他引：22
东天山区域韧性剪切带是近年来中国西部发现的大型剪切带之一,称秋格明塔什－黄山韧性剪切带,东西长逾６００ｋｍ,宽５～２０ｋｍ,位于两大板块碰撞接合地带。变形组构较发育,分四期变形,序列演化明显,应变测量属平面单剪,剪切位移量达７５ｋｍ以上。存在逆冲剪切和韧－脆性剪切变形转换。变形时代为海西中晚期,介于３１０～２５０Ｍａ间,高峰期为２９０～２６５Ｍａ,变形机制属地壳中深层次塑性流变和韧性剪切,其与两大板块间的俯冲－碰撞构造演化密切相关,并经历了多期多阶段演变。它的厘定和研究对再造该区构造演化和金铜矿产勘查预测有重要意义。 相似文献
3.
文章对纳米比亚欢乐谷地区白岗岩型铀矿的铀矿物学、成矿期次、主要控矿因素、成矿物质来源及成矿机理等进行了系统的研究,认为白岗岩型铀矿受到构造、岩性、地层、基性岩脉和后期热液活动等因素的综合控制。矿体主要产于褶皱的拐弯处、穹窿边缘及构造变异(转折、膨大)部位,这些构造为铀矿化提供了充足的赋存空间;同时千岁兰区域性断裂为铀的活化迁移提供了通道;在岩性方面,矿化白岗岩具有专属性,只有D、E型白岗岩成矿,其他类型白岗岩不成矿,而且矿化白岗岩主要侵入于卡里毕比组和卡塞布组;后期流体也对铀成矿具有叠加改造作用,该期铀矿化与侏罗纪基性岩浆的侵入密切相关。另外经研究发现,白岗岩型铀矿主成矿期铀来源于富铀的前达马拉基底,热液叠加改造期的铀可能来自于原生铀矿物本身,据此构建了一个全新的四阶段三期的"四维"成矿模式。 相似文献
4.
东昆仑造山带东段哈图沟–清水泉–沟里韧性剪切带塑性变形及动力学条件研究 总被引：1，自引：0，他引：1
东昆仑造山带东段哈图沟–清水泉–沟里韧性剪切带记录了多个旋回的造山作用,本文通过对韧性剪切带中石英c轴组构和显微构造特征测试分析,探讨东昆仑造山带东段陆块间俯冲拼合及地壳伸展减薄的形成机制。结果显示,韧性剪切带变形温度介于380~650℃之间,形成环境为中–高绿片岩相到低角闪岩相,剪切带内差异应力值介于173~509 MPa之间,应变速率介于6.93×10–14~1.43×10–8 s–1之间,主体为10–11~10–10 s–1,显示韧性剪切带变形是快速俯冲作用下的产物,越靠近东昆仑造山带东段东昆中断裂带其变形温度、差异应力值及相应的应变速率值越大,表明东昆仑造山带东段韧性剪切变形中心为东昆中断裂带。利用不同方法所计算出的韧性剪切带运动学涡度值,显示韧性剪切带早期瞬时运动学涡度(0.56~1)对应于东昆仑造山带东段东昆南与东昆仑造山带东段东昆北陆块间俯冲的初始阶段,中后期运动学涡度(0.25~0.91)应当对应于东昆南与东昆北陆块间的俯冲碰撞阶段,最晚期的C′瞬时运动学涡度(0.19~0.51)则对应于后造山的伸展阶段。通过石英c轴组构结合其宏微观构造特征,认为东昆中构造带至少经历了3个期次的构造运动,分别为加里东晚期的逆冲兼左行走滑剪切作用、晚海西–印支期的逆冲兼右行走滑剪切作用和燕山早期及之后的脆韧性–脆性的左行走滑剪切作用。 相似文献
5.
中国大陆岩石圈壳幔韧性剪切带系统 总被引：12，自引：0，他引：12
众多地震测深剖面的地质构造解析显示,大陆岩石圈存在既有显著差异又有密切联系的两套断裂系统,即以地壳表层脆性剪切带为主的浅层断裂系统和以切割莫霍界面的壳幔韧性剪切带为主的深部断裂系统。根据地震测深速度结构特征,结合深部构造岩石地球化学的综合研究,将切割莫霍界面或壳幔过渡带的壳幔韧性剪切带划分为三类(俯冲带、缝合带和剪切带)五型(大陆岩石圈边缘海沟俯冲带、大陆岩石圈碰撞缝合带、挤压型壳幔韧性剪切带、伸展型壳幔韧性剪切带和走滑型壳幔韧性剪切带)。建立起中国大陆岩石圈构造变形由地壳表层向深部扩展以及由壳幔过渡带向地壳中上部扩展的岩石圈双向扩展模式。壳幔韧性剪切带既是无机成因天然气等深部流体的通道,又是地震活动区的发震构造之一,因此研究大陆岩石圈壳幔韧性剪切带具有重要学术价值和实际意义。 相似文献
6.
本文对纳米比亚欢乐谷地区与铀成矿关系密切的白岗岩进行了系统的主量元素、微量元素及Sr-Nd同位素研究。结果表明,矿化白岗岩具有较高的SiO_2(68.81%~76.02%,平均值73.11%),富钾,A/CNK为0.96~1.07,平均值1.01,为亚碱性系列的准铝质-弱过铝质岩石。岩石富集轻稀土[LREE/HREE=2.53~7.71;(La/Yb)_N=2.14~10.40],Eu亏损中等,高Rb/Sr比值(2.03~5.50,平均值4.36),岩石同时富集Rb、Th、U、K及Pb等大离子亲石元素,亏损Ba、Nb、Ta及Sr等元素。岩石的初始~(87)Sr/~(86)Sr比值为0.73035~0.79345,ε_(Nd)(t)值为-13.5~-17.4,晶质铀矿的ε_(Nd)(t)值为-14.8~-16.5,两阶段Nd模式年龄为2.43~2.56Ga。元素和Sr-Nd同位素地球化学特征表明矿化白岗岩是在碰撞后的伸展构造环境中形成的,主成矿期的成矿物质来源于富铀的前达马拉基底;热液叠加改造期的铀可能来源于原生铀矿物本身。 相似文献
7.
腾冲地块高地热异常区晚白垩世-始新世钾玄质强过铝花岗岩岩石地球化学、年代学特征及构造意义 总被引：3，自引：2，他引：1
腾冲地块高地热异常区清水左所营初糜棱岩化黑云母二长花岗岩岩体、新华黑石河热田强糜棱岩化黑云母二长花岗岩岩体、热海热田硫磺塘硅化碎裂正长花岗岩岩体变形变质、岩石地球化学及锆石年代学的研究表明,晚白垩世(73Ma)初糜棱岩化黑云母二长花岗岩岩体为高温钾玄质强过铝花岗岩,形成于活动大陆边缘火山弧-后碰撞转换或过渡构造环境,并经历强烈伸展变形作用,普遍发育早期近水平-低角度(30°)韧性伸展剪切糜棱面理,局部发育晚期高角度右旋走滑挤压韧性糜棱面理;始新世(48~46Ma)强糜棱岩化黑云母二长花岗岩岩体、硅化碎裂正长花岗岩岩体为中-高温钾玄质强过铝花岗岩,并具铝质A型花岗岩特征,形成于后碰撞-板内构造环境,以发育晚期高角度(70°~87°)右旋走滑挤压韧性糜棱面理为特征,其右旋走滑韧性剪切变形时代晚于始新世(48~46Ma)。晚白垩世-始新世钾玄质强过铝花岗岩的形成与俯冲-碰撞造山隆升后的伸展垮塌、拆沉地幔物质上涌玄武质岩浆底侵和地壳部分熔融作用密切相关。始新世-第四纪岩浆活动与高地热异常区(带)空间上密切伴生,新近纪晚期-第四纪构造活动主要表现为脆性走滑-拉张正断层和构造拉分断陷盆地的形成,构造断陷边界断裂与深部岩浆活动是导致腾冲地区高地热异常区(带)中-高温地热温泉沿走滑-拉张断裂带集中分布的主要原因。 相似文献
8.
对纳米比亚欢乐谷地区的白岗岩进行了详细的岩石学和地球化学特征研究,初步讨论了白岗岩成因。研究结果表明,欢乐谷地区白岗岩的矿物组成和化学成分显示了较大的变化范围,白岗岩岩性主要为正长花岗岩和二长花岗岩,部分为碱长花岗岩、英云闪长岩和花岗闪长岩等。根据岩石和矿物的颜色、结构、矿物学特征、矿化特点等,可将其划分为A、B、C、D、E、F 6种类型,并且从A类至F类,白岗岩的形成时间顺序为由早到晚。白岗岩具有高硅、高碱和低锰、镁、钠、磷、钙的特点,为高钾钙碱性系列钾玄岩系列的准铝质过铝质岩石。不同类型的白岗岩主量元素特征未显示出它们是同源岩浆演化的产物,而可能是达马拉造山运动晚期构造演化不同阶段的产物。 相似文献
9.
西秦岭勉略带陆内构造变形研究 总被引：12，自引：3，他引：9
秦岭造山带勉略缝合带是古特提斯洋盆向北俯冲形成的华北与华南最后拼接带。这个主缝合带俯冲-碰撞过程中以由北向南的一系列韧性逆冲推覆构造为特征,形成由前泥盆系、泥盆-石炭系和蛇绿混杂岩等不同构造岩片叠置的复杂构造带,碰撞时代从245Ma一直延续到230Ma左右。最近,作者对勉略缝合带内发育的韧性和脆性左行走滑剪切变形进行了研究,结果表明这些顺造山带的左行韧性走滑剪切变形带的变形时代为223±2Ma,与碰撞后花岗岩所确定的碰撞后构造环境的起始时间(225Ma)一致,显示这些韧性走滑剪切变形带是勉略带陆内变形初期变形产物。亦即华北、扬子大陆碰撞之后很快就转入陆内变形阶段,并且是以顺造山带的侧向走滑位移为主要变形方式。勉略带内顺造山带的脆性左行走滑断层的发育,表明这种顺造山带的侧向位移过程从深部到地壳浅层是一致的。因此,大陆碰撞在直接碰撞之后很快转变为顺造山带的侧向走滑位移为主的陆内变形,这种位移可能表现为两个大陆碰撞后的相对走滑,或是碰撞带中强烈变形部分顺造山带的侧向挤出,从而消减了正向碰撞所造成的地壳缩短和增厚。 相似文献
10.
辽南金州拆离断层带中花岗质岩石的变形:显微构造、组构与年代学分析 总被引：1，自引：0，他引：1
花岗岩(脉)在中下地壳韧性剪切带中普遍发育,如何正确鉴别剪切带中剪切前、剪切期及剪切后花岗岩(脉)以及正确理解剪切过程中构造变形与岩浆作用之间的关系一直是一个重要课题。本文以辽南金州拆离断层带为研究对象,选取中部地壳伸展作用过程中具有不同变形表现的花岗岩(脉)开展宏观-微观构造观察、石英EBSD组构分析及锆石LA-ICP-MS年代学测试等工作,从而进一步丰富构造-岩浆关系判别准则。剪切前花岗岩(脉)多变形强烈且具有后期固态变形叠加在早期高温岩浆组构之上的特点,而剪切期的花岗岩由于侵位的时间不同,岩石的变形程度也会不同。剪切晚期侵入的岩脉遭受了较弱的晶内塑性变形,而剪切早期的岩脉可以显示岩浆流动或结晶后高温至中温固态变形。从组构特点上看,剪切前和剪切期花岗质岩石石英c轴组构大多表现为中高温组构叠加有低温组构的特点。剪切后的花岗质岩石仅发生微弱的晶内变形或未变形而显示低温或无规律的组构特征。对五个典型的样品进行年代学测试,其结果符合相应的期次划分类型。应用宏观构造、显微构造与组构分析,结合年代学测试综合分析,对于辽南变质核杂岩构造-岩浆活动性进行了精细划分,包括134~130Ma初始伸展阶段,130~115Ma峰期伸展与强烈岩浆活动阶段,以及115Ma前后伸展作用结束。 相似文献
11.
12.
南阿尔金断裂的韧性剪切作用时代及其构造意义 总被引：6，自引：5，他引：1
位于阿尔金山腹地古元古界阿尔金群深变质岩系与中-新元古界浅变质岩系间的南阿尔金断裂,是1条以近于E-W走向,微向S高角度倾斜的大型逆冲断裂,它经历了韧性变形和脆性变形2个构造演化阶段.韧性剪切带的形成始于晚寒武世,强烈活动期为中奥陶世-志留纪(468.4～412.2Ma),早-中泥盆世、早石炭世、晚二叠世和早侏罗世时期,剪切带进入以高、中温为主的韧性变形期,随着时间推移,变形温度不断降低,剪切作用的强度明显减弱,早侏罗世后,南阿尔金断裂完全进入以脆性变形为主的构造演化阶段.南阿尔金断裂以北广泛分布的年龄区间为491.3 ±4.6～413.8±8.0Ma的钙碱性系列花岗岩和断裂南侧出露的时代为519±37～500±10Ma的榴辉岩和角闪糜棱岩,表明在发生极性向北的逆冲型韧性剪切作用前,沿南阿尔金断裂曾发生过自南而北的岩石圈尺度的俯冲作用.因此,南阿尔金断裂是阿尔金山腹地的1条重要的早古生代板块汇聚、碰撞带. 相似文献
13.
Thomas Leydier Philippe Goncalves Pierre Lanari Emilien Oliot 《Journal of Metamorphic Geology》2019,37(8):1129-1149
The inherited localization model for shear zone development suggests that ductile deformation in the middle and lower continental crust is localized on mechanical anisotropies, like fractures, referred to as shear zone brittle precursors. In the Neves area (Western Tauern Window, Eastern Alps), although the structural control of these brittle precursors on ductile strain localization is well established, the relative timing of the brittle deformation and associated localized fluid flow with respect to ductile deformation remains in most cases a matter of debate. The present petrological study, carried out on a brittle precursor of a shear zone affecting the Neves metagranodiorite, aims to determine whether brittle and ductile deformations are concomitant and therefore relate to the same tectonic event. The brittle precursor consists of a 100–500 µm wide recrystallized zone with a host mineral‐controlled stable mineral assemblage composed of plagioclase–garnet–quartz–biotite–zoisite±white mica±pyrite. Plagioclase and garnet preserve an internal compositional zoning interpreted as the fingerprint of Alpine metamorphism and fluid–rock interactions concomitant with the brittle deformation. Phase equilibrium modelling of this garnet‐bearing brittle precursor shows that metamorphic garnet and plagioclase both nucleated at 0.6 ± 0.05 GPa, 500 ± 20°C and then grew along a prograde path to 0.75 ± 0.05 GPa, 530 ± 20°C. These amphibolite facies conditions are similar to those inferred from ductile shear zones from the same area, suggesting that both brittle and ductile deformation were active in the ductile realm above 500°C for a depth range between 17 and 21 km. We speculate that the Neves area fulfils most of the required conditions to have hosted slow earthquakes during Alpine continental collision, that is, coupled frictional and viscous deformation under high‐fluid pressure conditions ~450°C. Further investigation of this potential geological record is required to demonstrate that slow earthquakes may not be restricted to subduction zones but are also very likely to occur in modern continental collision settings. 相似文献
14.
《Journal of African Earth Sciences》1999,28(3):675-691
The Ngondo Complex is one of the Pan-African plutons intruded in the West Cameroon Pan-African Orogenic Belt. The complex consists of three major groups of rocks: basic to intermediate rocks (diorites, granodiorites and minor gabbros), fined-grained granites and coarsed-grained granites successively emplaced in a metamorphic country rock of amphibolite-facies. Synkinematic emplacement of the complex, in relation with a ductile mega shear zone, is documented by a study of microstructures and foliation patterns which indicate a continuous transition from magmatic to high temperature solid-state deformation. The geometry of the internal foliation trajectories and the joint orientation in the complex suggest that the emplacement of the three groups of rocks was totally controlled by a N30° sinistral shear zone. Emplacement mechanisms, which are related in time and space to a continuum of deformation, may indicate a relative rheological change of the crust from ductile to brittle behaviour. 相似文献
15.
The metabasites and mylonitic granites of the East and South East of Chadegan in the Isfahan province are a part of the Sanandaj-Sirjan Zone. This region is a large-scale ductile shear zone which has experienced different phases of deformation and dynamothermal metamorphism. There are at least three phases of deformation in this area. During the first phase which was related to the subduction of the Neotethys oceanic lithosphere under the Iranian microcontinent, the study rocks have experienced regional metamorphism. The second deformational phase was concurrent with the collision between the Arabian plate and the Iranian plate in the Late Cretaceous and caused mylonitization of the metamorphic rocks. The NW–SE trending fold and thrust faults have formed in this stage. The mylonitization have been formed along the dextral transpressional faults. During the third stage of deformation and exhumation of the metamorphic complex, the mylonitic zones have been uplifted to the surface. In this the deformation phase, developed the current morphology of the rocks. The granites have been injected along the extensional shear zones related to the dextral transpressional displacements. These granites are related to the continental collision granites type and have been formed synchronous to the collision between the Arabian and the Iranian plate. Enrichment in LREEs comparison to HREEs and the negative Eu anomaly in the primitive mantle-normalized spidergram and Chondrite-normalized REE patterns support an intra-crustal origin for these granites. Upper continental crust-normalized REE patterns show that in terms of LREEs, are similar to Upper continental crust. 相似文献
16.
Zuzana Kratinová Karel Schulmann Jean-Bernard Edel Anne-Sophie Tabaud 《International Journal of Earth Sciences》2012,101(3):803-817
Orogenic compression-related fabrics (~340–335 Ma) were reworked during regional extensional deformation (~328–325 Ma) in
a large anatectic crustal domain of the Central Vosges (NE France). The extension was first accommodated by brittle dilation
affecting vertically anisotropic high-grade rocks associated with emplacement of subvertical granitic sheets. The AMS fabric
of granitoids is consistent with highly partitioned transtensional deformation marked by alternations of flat and steep foliations
and development of orthogonal lineations. This deformation passes to top-to-the-southwest ductile shearing expressed in southerly
migmatitic middle crust. The AMS fabric revealed moderately west-dipping foliations bearing subhorizontal NNW–SSE-trending
lineations and predominantly plane strain to prolate shapes. This fabric pattern is interpreted as a viscous response of stretched
partially molten crust during continuous ductile extension. Vertical ascent of voluminous granites and stoping of the upper
crust occurs further south. This gravity ascent triggered by extension leads to development of south-dipping AMS foliations,
south-plunging lineations and oblate fabrics in various crustal granites. Vertical shortening related to ascent of these (~325 Ma)
granitoids and persistent N–S stretching is responsible for reworking and remelting of originally vertical compression-related
fabric in roof supracrustal granites (~340 Ma) and development of highly prolate fabrics in these rocks. This work shows that
the finite shape of AMS fabric ellipsoid is highly sensitive to both strain regime and superpositions of orthogonal deformation
events. 相似文献
17.
纳米比亚欢乐谷地区斑状花岗岩成因及构造背景 总被引：1，自引：0，他引：1
对纳米比亚欢乐谷地区斑状花岗岩进行系统的地球化学及 Sr--Nd 同位素研究,并对其岩石成因及构造意义进行了讨论。结果表明,该斑状花岗岩为高钾钙碱性-钾玄岩系列的准铝质花岗岩; 岩石富碱、轻稀土和 Ｒb、Th、U、K、Pb 等大离子亲石元素,贫 Nb、Ta、Ti、Zr、Hf 等高场强元素,具有中等铕负异常。岩石锶初始值为 0. 715 61 ～0. 722 07,εNd( t) 为 －13. 9 ～ －12. 7,Nd 同位素模式年龄为2 025 ～2 153 Ma。揭示欢乐谷地区斑状花岗岩为同碰撞 S 型花岗岩,主要来源于古老地壳物质的重熔,是 Kalahari 克拉通和 Congo 克拉通碰撞造山的产物。 相似文献
18.
以矿区构造节理统计分析为基础,结合矿区地质特征及区域构造演化,分析了哈达门沟金矿区构造控矿特征及应力场演化。认为山前"钾化带"与矿体就位直接相关,它沟通了复式褶皱核部的隐伏岩体与浅部节理,并成为流体运移的主要通道。与成矿控矿有关的构造应力场可分为四期:第一期变形在新太古代的乌拉山旋回,最大主应力σ1方位15°～195°,共轭节理为NNW和NE向;在成岩、变质作用同时进行下除形成了区内透入性的强塑性叠加小褶皱外还有整体上的大型复背斜。第二期构造应力场作用时间在晚古生代,σ1方位约在160°～340°,形成近SN和NE向共轭节理和西侧的大桦背岩体,这一期有局部的矿化现象;前两期应力场形成了轴向近EW向的叠加褶皱、断裂和两期共轭剪节理等成矿前主要构造。第三期应力场处于主成矿期,变形为燕山运动中、晚期构造,σ1在290°方位近水平扭压,形成EW和NW向共轭剪节理;张扭性应力场使近EW向的节理弯曲变形,并形成追踪张节理,这两类裂隙成为主要的矿液通道及容矿空间。第四期构造应力场应在晚燕山运动及以后,为成矿后构造变形,σ1近直立,整体抬升使矿脉遭受剥蚀而出露地表。 相似文献
19.
20.
The Eastern Desert of Egypt is well known as a gold-mining district since ancient times. Gold mineralization is closely associated with the granitic rocks in such way that the mineralization is either hosted by or occurs immediately adjacent to the granite intrusions. Granitic rocks accompanying gold mineralization in the Eastern Desert can be grouped into three categories i.e. syn-late tectonic calc-alkaline granites, calc-alkaline to mildly alkaline granites of the transitional stage and post-tectonic alkaline granites.Tectonically, gold mineralization is linked with the tectonothermal stages that were operative during the evolution of the Arabian–Nubian Shield (ANS). During the primitive stages of the island-arc formation, pre-orogenic gold mineralization (auriferous exhalites) was formed by hot brines accompanying submarine volcanic activity. No role for the granite is observed in this stage. Syn-orogenic gold mineralization (i.e. gold hosted in altered ophiolitic serpentinites along thrust faults and in sutures, quartz veins hosted in the metavolcano-sedimentary assemblage and/or the I-type granitic rocks surrounding them) connected with the collision and accretion stage is characterized by emplacement of calc-alkaline (I-type) older granite batholiths. Shear fractures reflected in brittle–ductile shear zones and amphibolite-green schist facies regional metamorphism were broadly contemporaneous with this intense compressional tectonic regime. Available fluid inclusion microthermometry and isotopic studies reveal that both metamorphic and magmatic fluids related to the syn-late tectonic calc-alkaline granites were operative. A further indication for the role of the granites is indicated by the presence of some concentrations of Antimony, Bismuth, Molybdenum, Tungsten, Rubidium, Beryllium, Tin, Yttrium, Ytterbium, Tantalum and Niobium in some auriferous quartz veins in the Egyptian gold mines.In the cratonal development of the (ANS), the land underwent a transitional stage between the major subduction-related calc-alkaline magmatic activity and the subsequent post-tectonic plutonism represented by the alkaline granites. This transitional stage is dominated by the eruption of Dokhan volcanics and deposition of molass-type Hammamat sediments. At ~ 590–530 Ma, the Arabian–Nubian Shield was deformed by post-accretionary structures, in the form of N-trending shortening zones such as the Hamisana shear zone and NW-trending strike-slip faults such as the Najd fault system. The regional NNW–SSE directed extension opened spaces that were progressively sealed with different magmatic phases including among them a considerable proportion of rocks referred to as “younger granites” in the Egyptian literature. Late-orogenic gold mineralization connected with the transitional stage is represented principally by the gold-bearing quartz veins traversing Hammamat molasse sediments, quartz veins traversing syn-extensional younger granites and generally quartz veins in ductile to brittle shears related to the Najd fault system and within Hamisana shear zone and its splays.By the end of Pan African orogeny until the Tertiary, the basement was intermittently intruded by a number of sub-alkaline to per alkaline granite bodies that host Mo, Sn, W, Nb–Ta and U mineralization in the Eastern Desert of Egypt. Anorogenic gold mineralization connected with post-orogenic granites is represented by small amounts of the element in disseminations, stockworks and quartz veins of Sn–W–Ta–U mineralization.The present review shows that gold mineralization in Egypt is an expression of two major cycles with distinct magmatic and tectonic characteristics, and the two cycles were separated by a transitional stage. The emplacement of granites in the compressional cycle played an important role in metamorphosing the country rocks by producing the heat energy required for the regional metamorphism and the providing of the magmatic fluids. The H2O–CO2 fluids enriched in volatiles were released at the greenschist–amphibolite facies transition at 450°–500 °C and mixed with the I-type calc-alkaline granite related fluids and both moved down a temperature gradient away from the amphibolite-green schist transition at depth to a lower temperature regime in the upper levels where it is deposited in brittle–ductile shear zones. With the extensional cycle, the syn-extensional granite intrusions acted as heat engine in such way that the heat of the granite drove the convective cells to circulate through the auriferous host-granite contacts, leaching gold and other elements and depositing it in structurally favorable sites. In addition, the contrasts in competency between the granites with brittle deformational characteristics and the surrounding country rocks with a ductile response to stress, led to a generation of extensive fracture pattern within the more competent unit. 相似文献