岩石学报
巖石學報
암석학보
ACTA PETROLOGICA SINICA
2004年
4期
837-854
,共18页
菱镁矿和滑石成因%地球动力学演化%剪切带%显微结构%流体包裹%西喀尔巴阡山脉
蔆鎂礦和滑石成因%地毬動力學縯化%剪切帶%顯微結構%流體包裹%西喀爾巴阡山脈
릉미광화활석성인%지구동역학연화%전절대%현미결구%류체포과%서객이파천산맥
Magnesite and talc genesis%Geodynamic evolution%Shear zones%Microstructures%Fluid inclusions%Western Carpathians
本文总结并报导了斯洛伐克西喀尔巴阡山脉内侧的石炭纪岩石中产出的菱镁矿和滑石成因的最新资料.这些矿床赋存于Veporicum构造超单元中和该超单元与Gemericum的接触带中.北部Sinec成矿带是主要的菱镁矿和滑石矿化区,产出的主要矿床有Kokava,Sinec,Samo,Hnsta-Mutnik等矿床.而南部的Ochtina成矿带只产有菱镁矿床,主要矿床包括在Dubrava地体上的Dubrava,Mikov?JedL'vec;Luben韐,Ochtina,Kosice-Bankov,Banisko,Medvedia等矿床.菱镁矿形成于变质M1期石炭系中方解石被白云石和菱镁矿连续交代过程(北矿带成矿温度为280～400℃,南矿带成矿温度为370～420℃;Radvanec＆Prochska,2001;Kodera＆Radvanec,2002).Permoscythian蒸发卤水提供了Mg.成矿事件和华力西期碰撞后运动有关.拉伸构造和高热流值促使成矿热液系统的产生.滑石矿化则形成于稍晚的不同期变质事件(M2),成矿流体来源也与菱镁矿化不同.构造的、微构造的、变质的以及地质年代学的数据将滑石成矿作用和阿尔卑斯上白垩系的构造地热事件AD2联系在一起.AD2事件是阿尔卑斯碰撞(AD1)地壳加厚和变质核杂岩体起源的结果,体现在地壳不整合面上的区域拉伸,及开放系统中大规模热液流动.这一过程在更靠近Veporic热穹的北带区域(Sinec剪切带)很显著,而向着Veporic热穹的周围部分(南Ochtina带),M2变质过程和块滑石化则逐渐减弱.Sinec剪切带是北Sinec带中突出的AD2-AD3结构,白云石/菱镁矿透镜体(在M1期交代造成的)和相伴随的岩石夹杂在AD1中更坚硬的基底岩石之中.本研究证明了AD2中块滑石化的普遍性,滑石和白云石2形成于拉伸显微构造中(变质过程M2;温度为490～540℃,压力为240～330MPa).在Sinec带中AD3阶段的对偶剪切作用形成了该带中的滑石矿.它是AD2事件从去顶到区域扭压剪切的动力学转变过程的逐步延续.北Sinec带使AD3变形处于由坚硬岩石包围的软岩石的狭窄的剪切带中,而在南Ochtina带中AD3变形产生在由里面漂浮着坚硬碳酸盐块的软的岩石柱中.在Ochtina带中,在AD2和AD3阶段由于M2期较低的P-T条件和变形梯度导致了该区有经济价值的滑石矿化不发育.总之,现有的研究结果能用作阿尔卑斯型地体中菱镁矿和滑石找矿的基本标志.
本文總結併報導瞭斯洛伐剋西喀爾巴阡山脈內側的石炭紀巖石中產齣的蔆鎂礦和滑石成因的最新資料.這些礦床賦存于Veporicum構造超單元中和該超單元與Gemericum的接觸帶中.北部Sinec成礦帶是主要的蔆鎂礦和滑石礦化區,產齣的主要礦床有Kokava,Sinec,Samo,Hnsta-Mutnik等礦床.而南部的Ochtina成礦帶隻產有蔆鎂礦床,主要礦床包括在Dubrava地體上的Dubrava,Mikov?JedL'vec;Luben韐,Ochtina,Kosice-Bankov,Banisko,Medvedia等礦床.蔆鎂礦形成于變質M1期石炭繫中方解石被白雲石和蔆鎂礦連續交代過程(北礦帶成礦溫度為280～400℃,南礦帶成礦溫度為370～420℃;Radvanec＆Prochska,2001;Kodera＆Radvanec,2002).Permoscythian蒸髮滷水提供瞭Mg.成礦事件和華力西期踫撞後運動有關.拉伸構造和高熱流值促使成礦熱液繫統的產生.滑石礦化則形成于稍晚的不同期變質事件(M2),成礦流體來源也與蔆鎂礦化不同.構造的、微構造的、變質的以及地質年代學的數據將滑石成礦作用和阿爾卑斯上白堊繫的構造地熱事件AD2聯繫在一起.AD2事件是阿爾卑斯踫撞(AD1)地殼加厚和變質覈雜巖體起源的結果,體現在地殼不整閤麵上的區域拉伸,及開放繫統中大規模熱液流動.這一過程在更靠近Veporic熱穹的北帶區域(Sinec剪切帶)很顯著,而嚮著Veporic熱穹的週圍部分(南Ochtina帶),M2變質過程和塊滑石化則逐漸減弱.Sinec剪切帶是北Sinec帶中突齣的AD2-AD3結構,白雲石/蔆鎂礦透鏡體(在M1期交代造成的)和相伴隨的巖石夾雜在AD1中更堅硬的基底巖石之中.本研究證明瞭AD2中塊滑石化的普遍性,滑石和白雲石2形成于拉伸顯微構造中(變質過程M2;溫度為490～540℃,壓力為240～330MPa).在Sinec帶中AD3階段的對偶剪切作用形成瞭該帶中的滑石礦.它是AD2事件從去頂到區域扭壓剪切的動力學轉變過程的逐步延續.北Sinec帶使AD3變形處于由堅硬巖石包圍的軟巖石的狹窄的剪切帶中,而在南Ochtina帶中AD3變形產生在由裏麵漂浮著堅硬碳痠鹽塊的軟的巖石柱中.在Ochtina帶中,在AD2和AD3階段由于M2期較低的P-T條件和變形梯度導緻瞭該區有經濟價值的滑石礦化不髮育.總之,現有的研究結果能用作阿爾卑斯型地體中蔆鎂礦和滑石找礦的基本標誌.
본문총결병보도료사락벌극서객이파천산맥내측적석탄기암석중산출적릉미광화활석성인적최신자료.저사광상부존우Veporicum구조초단원중화해초단원여Gemericum적접촉대중.북부Sinec성광대시주요적릉미광화활석광화구,산출적주요광상유Kokava,Sinec,Samo,Hnsta-Mutnik등광상.이남부적Ochtina성광대지산유릉미광상,주요광상포괄재Dubrava지체상적Dubrava,Mikov?JedL'vec;Luben겹,Ochtina,Kosice-Bankov,Banisko,Medvedia등광상.릉미광형성우변질M1기석탄계중방해석피백운석화릉미광련속교대과정(북광대성광온도위280～400℃,남광대성광온도위370～420℃;Radvanec＆Prochska,2001;Kodera＆Radvanec,2002).Permoscythian증발서수제공료Mg.성광사건화화력서기팽당후운동유관.랍신구조화고열류치촉사성광열액계통적산생.활석광화칙형성우초만적불동기변질사건(M2),성광류체래원야여릉미광화불동.구조적、미구조적、변질적이급지질년대학적수거장활석성광작용화아이비사상백성계적구조지열사건AD2련계재일기.AD2사건시아이비사팽당(AD1)지각가후화변질핵잡암체기원적결과,체현재지각불정합면상적구역랍신,급개방계통중대규모열액류동.저일과정재경고근Veporic열궁적북대구역(Sinec전절대)흔현저,이향착Veporic열궁적주위부분(남Ochtina대),M2변질과정화괴활석화칙축점감약.Sinec전절대시북Sinec대중돌출적AD2-AD3결구,백운석/릉미광투경체(재M1기교대조성적)화상반수적암석협잡재AD1중경견경적기저암석지중.본연구증명료AD2중괴활석화적보편성,활석화백운석2형성우랍신현미구조중(변질과정M2;온도위490～540℃,압력위240～330MPa).재Sinec대중AD3계단적대우전절작용형성료해대중적활석광.타시AD2사건종거정도구역뉴압전절적동역학전변과정적축보연속.북Sinec대사AD3변형처우유견경암석포위적연암석적협착적전절대중,이재남Ochtina대중AD3변형산생재유리면표부착견경탄산염괴적연적암석주중.재Ochtina대중,재AD2화AD3계단유우M2기교저적P-T조건화변형제도도치료해구유경제개치적활석광화불발육.총지,현유적연구결과능용작아이비사형지체중릉미광화활석조광적기본표지.
This paper summarizes recent data about magnesite and talc genesis in Carboniferous host rocks of Western Carpathians (Slovakia), which occur in two distinct belts in tectonic superunit Veporicum and its contact zone with Gemericum. The northern Since magnesite and talc belt (with main deposits Kokava, Sinec, Samo, Hnust'a-Mutnik) contains economic accummulation of magnesite Kosice - Bankov, Banisko, Medvedia) the magnesite is dominating.The magnesite genesis by successive replacement of Carboniferous calcite to dolomite and magnesite during metamorphic process M1 (northern belt 280 ～ 400℃, southern belt 370 ～ 420℃; Radvanec & Prochaska, 2001; Kodera & Radvanec, 2002), being supplied by Mg from Permoscythian evaporitic bittern brines, relates to Variscan post-collisional (post-VD) evolution. The extensional tectonics and the high heat flow facilitated the generation of a hydrothermal system.The time-separated later metamorphic and sourcely different fluid flow event (M2; l. C.) produced talc. Tectonic, microtectonic,al., 1996) tectonothermal event AD2. This event, being the consequence of Alpine collisional (AD1) crustal thickening and metamorphic core complex origin, meant regional extension and pervasive fluid flow of open system in crustal discontinuities. This process was prominent in the northern belt (Sinec shear zone) located more closely to Veporic thermal dome, while towards its peripheral parts (southern Ochtina belt) the M2 metamorphic process and steatitization gradually weakened.Studies from Sinec shear zone (being the prominent AD2-AD3 structure of northern Sinec belt), where the dolomite/magnesite lenses (replacement in M1) and their accompanying lithology were in AD1 sandwitched between more competent basement blocks,proved in AD2 the pervasite steatitization, the talc and dolomite 2 origin in extensional microstrnctures (metamorphic process M2; 490～540℃, 240 ～330 Mpa, l. C.).The economic accummulations of talc in Sinec belt are the products of antithetic shearing during the AD3 phase, being the gradual continuation of AD2 (change of kinematics from unroofing to regional transpressional shearing). Contrary to the northern Sinec belt having located the AD3 deformation into narrow shear zone with soft lithology surrounded by hard lithology, in southern Ochtina belt the deformation AD3 was accommodated by wide soft rock column with rigid carbonate blocks floating inside. The lower P-T (M2) conditions and deformational gradient in Ochtina belt during AD2 and AD3 phases caused why no economic talc accummulations developed there. The results of presented study can be used as general criteria for magnesite and talc prospection in Alpine type terranes.
