王河錦 周釗 王玲 苑蕾
WANG HeJin1,2,ZHOU Zhao2,WANG Ling1,2 and YUAN Lei2
1. 造山帶與地殼演化教育部重點實驗室,北京 100871
2. 北京大學地球與空間科學學院,北京 100871
1. Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,Beijing 100871,China
2. School of Earth and Space Sciences,Peking University,Beijing 100871,China
2014-01-23 收稿,2014-07-20 改回.
湖南北部楊家坪一帶出露有中新元古宇和下古生界。他們是否變質(zhì)存在兩種主要的觀點。如:盧良兆(1987)認為中新元古宇(板溪群,冷家溪群)經(jīng)歷了低綠片巖相區(qū)域低溫動力變質(zhì)作用并達到了“絹云母-綠泥石”級,其發(fā)生時間為中晚元古宙,而震旦和下古生界為雪峰運動后的沉積蓋層。另一種觀點(金文山和孫大中,1997)則認為,湖南的中新元古宇遭受了“絹云母”級亞綠片巖相到低綠片巖相的區(qū)域變質(zhì)作用,其溫度范圍為200 ~400℃,震旦-志留系則為雪峰運動(1000Ma)后的沉積蓋層。前者是根據(jù)礦物組合分析得出的結論,后者則有自生層狀礦物組合與結晶度資料的數(shù)據(jù)。朱明新和王河錦(2001)運用國際上可對比的伊利石結晶度、多型、b0值等方法識別出了湖南東部長沙-澧陵-瀏陽一帶冷家溪群和板溪群存在的淺變質(zhì)和近變質(zhì)作用;王河錦等(2002)運用同樣的國際上可對比的方法得出了湖南中部黃土店-仙溪中新元古宇和下古生界經(jīng)歷了甚低級變質(zhì)作用的影響。Wang et al.(2004)確定出了湘西北沅古坪一帶中新元古宇和下古生界遭受了近變質(zhì)作用的影響。已有資料表明,由東到西,中新元古宇和下古生界所遭受的變質(zhì)作用強度略變低,北部如何,目前尚無資料描述。其它描述了湖南中新元古宇變質(zhì)的文獻還有:吳雪華等(1965)、喻水純(1987)、賈寶華(1995)、候光久和索書田(1996)、鮑振襄等(1999)、車勤建等(2005)和高林志等(2011)。
本研究運用國際上可對比的碎屑巖低溫變質(zhì)理論和方法(Frey,1987;Frey and Robinson,1999;Eberl et al.,1990;Rahn et al.,1995;M?hlmann,1996;Schmidt et al.,1997;Mullis et al.,2002)對湘北楊家坪一帶中新元古宇和下古生界進行分析研究,以希查明甚低級變質(zhì)作用(Very low grade metamorphism)在區(qū)域上的影響變化,并恢復該區(qū)構造熱演化的歷史。
湘北在大地構造上位于揚子地塊江南“古陸”(金文山和孫大中,1997)或華南古陸“殼”(馬麗芳,2002)。冷家溪早期該古陸裂解為微陸塊,本區(qū)形成邊緣裂谷深海次深海環(huán)境,沉積了泥質(zhì)、火山-碎屑濁積巖組合。冷家溪晚期-新元古早期發(fā)生武陵運動,裂谷關閉形成碰撞帶,隨后產(chǎn)生系列褶皺抬升和剝蝕;使得作為湖南最老的冷家溪群出現(xiàn)在武陵運動不整合面之下,并成為揚子地臺的一部分。其后的新元古宇板溪群平行不整合于震旦系之下。冷家溪群由系列碎屑巖-火山物質(zhì)和深海沉積物構成,如砂質(zhì)粉砂質(zhì)板巖、雜砂巖、凝灰?guī)r和變質(zhì)火山巖石等(湖南省地質(zhì)礦產(chǎn)局,1988)。板溪群下部的馬底驛組(Pt3bnm)主要由系列泥質(zhì)和砂質(zhì)板巖組成,而上部的五強溪(Pt3bnw)組則主要由石英砂巖及板巖夾層構成。形成于雪峰運動之后的震旦系主要由沉積蓋層組成;其沉積物具有寒冷氣候的特征;組成的巖石有碎屑砂巖、板巖、白云巖等等(湖南省地質(zhì)礦產(chǎn)局,1988,1997)。下古生界寒武系主要由灰?guī)r、泥質(zhì)灰?guī)r和泥灰?guī)r組成;底部有一層黑色碳質(zhì)頁巖或板巖。奧陶系主要由灰?guī)r、泥質(zhì)灰?guī)r和白云質(zhì)灰?guī)r組成。志留系主要由頁(板)巖和砂巖組成。上古生界和中生界主要出露于剖面的南部和剖面以北區(qū)(圖1)。其它有關湖南前寒武系研究與討論可參見:劉海臣和朱炳泉(1994)、車勤建等(2005)、伍光英等(2005)、高林志等(2011)、孫海清等(2012)和孟慶秀等(2013)。
33 個富含粘土質(zhì)的巖石樣品(板巖、頁巖、泥灰?guī)r等)采集于楊家坪以南到磺廠的元古宇和下古生界剖面,平均1 ~5km 間隔,剖面約長55km(圖1)。約50g 樣品用錘子砸碎至0.5 ~1cm 直徑大小,后用DF-4 錘式碎樣機碎樣約25s。根據(jù)Stocke 沉積法富集<2μm 顆粒,用LXJ-64-1 離心機去除懸浮液中的液體。沉淀法備制定向粘土片,密度>3mg/cm2,室溫條件下自然干燥。Kisch(1991)標樣用于伊利石結晶度Kübler 指數(shù)(Kübler,1964)的校正。粘土礦物顆粒粒度大小由軟件MudMaster (Eberl et al.,1996)分析計算,晶格應變由SHAPECT(Wang and Zhou,2000,2005)軟件分析計算。衍射儀測量條件請參考王河錦等(2002)。
石英、伊利石、綠泥石、斜長石為巖石的主要物相。石膏見于剖面北部的冷家溪群。碳酸鹽主要產(chǎn)于下古生界寒武系和奧陶系,部分產(chǎn)于志留系。混層粘土礦物主要為伊蒙混層和綠蒙混層,僅見于成巖帶(見下一節(jié))。高嶺石僅發(fā)現(xiàn)在最南部的志留系。菱沸石產(chǎn)于下古生界寒武系和志留系。由這些礦物組合及產(chǎn)狀難以判定變質(zhì)作用是否存在。所有礦物組合、伊利石結晶度、b0值、多型、粒度大小、晶格應變以及樣品位置、地層、巖性資料見表1。
Kisch(1991)標樣用于伊利石結晶度Kübler 指數(shù)的測試校正。校正后的Kübler 指數(shù)可在國際范圍進行對比,其近變質(zhì)帶的界限為0.21 ~0.38°Δ2θ。本剖面中新元古宇和下古生界Kübler 指數(shù)變化范圍0.21 ~0.67°Δ2θ,中新元古宇(風化樣品除外)變化范圍為0.21 ~0.24°Δ2θ,而下古生界為0.28 ~0.67°Δ2θ。這表明中新元古宇處于高近變質(zhì)作用范圍,而下古生界則跨越了近變質(zhì)作用和成巖作用。區(qū)域上看,下古生界遭受的近變質(zhì)作用巖石為與元古宇緊密相連的寒武系和奧陶系。表明北部楊家坪一帶為近變質(zhì)的中心地帶,近變質(zhì)作用范圍包括了下古生界的寒武系和奧陶系。而遠離該中心的中新元古宇的下古生界則基本沒遭受近變質(zhì)作用的影響。
20 世紀70 年代Sassi and Scolari(1974)和Guidotti and Sassi(1976)提出了云母b0值地質(zhì)壓力計。其基本原理是隨著壓力的增加,K 云母發(fā)生IV 次和VI 次配位多面體的替代,使得晶格發(fā)生變化導致b0值增大,從而根據(jù)b0值的大小可以反推K 云母形成時的壓力。當然,云母b0值地質(zhì)壓力計是建立在被地質(zhì)事實證實的基礎上的,如Sassi and Scolari(1974)根據(jù)已經(jīng)被公認的不同變質(zhì)壓力地質(zhì)體(西班牙Bosost 低壓-美國N. New Hampshire 中低壓-新西蘭Otago 中高壓-日本Sanbagawa 高壓系列泥質(zhì)變質(zhì)巖)統(tǒng)計出來的K 云母b0值的分布圖描繪了低壓-中低壓-中高壓-高壓系列K 云母b0值分布特征,非常清晰的描述了云母b0值隨壓力增大b0值分布曲線也隨之增大的特點。此外,Guidotti and Sassi(1986)還進一步提出了低中高三種壓力類型的界限:b0<0.9000nm 為低壓類型,0.9000nm <b0<0.9040nm 為中壓類型,而b0>0.9040nm 為高壓類型。值得指出的是,云母b0值地質(zhì)壓力計是適用于泥質(zhì)變質(zhì)地質(zhì)體的一種估計變質(zhì)壓力的方法,不應該超范圍使用,如不應該用于成巖作用和沉積作用樣品的壓力估計。其誤差與b0值測試條件相關,本文為±0.0001nm。根據(jù)本區(qū)近變質(zhì)作用區(qū)巖石所獲得的8 個b0值,其波動范圍為:0.9000 ~0.9045nm,平均0.9017nm。因而,估計的近變質(zhì)作用壓力為中低壓變質(zhì)壓力類型。這與剖面較近的南部黃土店中新元古宇-下古生界甚低級變質(zhì)(王河錦等,2002)以及西部沅古坪一帶的中新元古宇-下古生界近變質(zhì)壓力(中低壓)(Wang et al.,2004)一致,而略低于東部長沙-醴陵-瀏陽一帶的中新元古宇甚低級變質(zhì)壓力(中等壓力)(朱明新和王河錦,2001)。
表1 地層、巖性、礦物組合、伊利石結晶度、b0 值、多型、粒度大小參數(shù)、晶格應變以及樣品位置Table 1 Stratum,petrology,mineral assemblage,illite crystallinity Kübler Index (KI),b0 cell dimension of K-white mica,polytype,mean logarithms thickness (α),logarithms variance (β2),general ripening (α×β2),mean thickness,lattice strain (τ)and sample localities
盡管還存在許多不同的觀點(Merriman and Roberts,1985;Frey,1987;Dong and Peacor,1996;Merriman and Peacor,1999),但是,許多研究者已經(jīng)證實(Yoder and Eugster,1955;Maxwell and Hower,1967;Ylagan et al.,1996)伊利石多型的演化由1Md到2M1是與蒙脫石經(jīng)伊蒙混層向伊利石轉(zhuǎn)變相伴而生的。因而,伊利石多型也可用于監(jiān)測由成巖作用到變質(zhì)作用的轉(zhuǎn)變。通常,1Md到2M1的轉(zhuǎn)變發(fā)生在成巖晚期到變質(zhì)作用的開始。有關多型含量的測量與計算是參照ICDD-2005 數(shù)據(jù)庫(International Centre for Diffraction Data,PDF-2 Release 2005)的資料進行的;其中,1M 多型獨有(112)、(112)、(023)衍射峰,而2M1多型獨有(114)、(114)及(025)衍射峰,由此可區(qū)別二種不同的多型。需要特別指出的是,當伊利石含量少,又為混合物時,多型的鑒別是極為困難的。同樣,巖石中砂質(zhì)含量偏高時,碎屑物質(zhì)中所含碎屑云母極易影響多型的分析測試。由于碎屑云母多為2M1多型,因而,常常造成2M1多型云母含量的過高估計。實驗結果表明:元古宇近變質(zhì)帶伊利石多型為2M1,而下古生界近變質(zhì)巖石以及成巖帶巖石所含伊利石多型為2M1+1M 混合類型。這表明,成巖帶巖石含有碎屑云母。
圖2 伊利石結晶度Kübler 指數(shù)與對數(shù)平均粒度α 的關系(a)和與對數(shù)粒度頻數(shù)β2 的關系(b)Fig.2 Relation between the Kübler Index and α (a)and relation between the Kübler Index and β2(b)
Eberl et al.(1990)的研究成果表明大多數(shù)粘土礦物顆粒經(jīng)歷過Ostwald 成熟效應而重結晶,其顆粒大小分布具有典型對數(shù)正態(tài)分布特征。Brime and Eberl(2002)和Bove et al.(2002)的研究成果進一步表明由成核到面積控制生長過程,顆粒大小分布的模式為漸近線轉(zhuǎn)為對數(shù)正態(tài)分布。由此可知,溫度越高或者成巖程度越高或者變質(zhì)級別越高,粘土礦物顆粒越大。由此粘土礦物顆粒的大小和分布特征可以描述粘土礦物的形成條件。
本文運用X 射線中的Bertaut-Warren-Averbach 實驗技術(Bertaut,1950;Warren and Averbach,1950;MudMaster 軟件,Eberl et al.,1996)進行粘土礦物顆粒大小的測試;由動差計算(Langford et al.,2000)和實驗法(Drits et al.,1997)確定的對數(shù)正態(tài)分布參數(shù)用于確定伊利石一致散射平均大小(mean coherent scattering domain,CSD)。由對數(shù)平均顆粒大小(α,mean of logarithms of the observations)和對數(shù)顆粒頻數(shù)(β2,the variance of the logarithms of the observations)(Eberl et al.,1990)與伊利石結晶度Kübler 指數(shù)的關系(圖2a,b)表明,KI-α 缺乏良好的線性關系,而KI-β2僅具有弱線性關系。這表明,單一對數(shù)顆粒大小或?qū)?shù)顆粒頻數(shù)特征無法完整地描述粘土礦物顆粒在成巖和變質(zhì)過程中成熟效應的變化,需要一個較為完整的能夠描述總體變化的參數(shù)才可。為此,我們提出對數(shù)總成熟效應(GLR:general logarithmic ripening)參數(shù)即:GLR =α ×β2來描述粘土礦物顆粒的生長(數(shù)字)特征。本區(qū)對數(shù)總成熟效應具有兩組不同的分布特征即近變質(zhì)作用區(qū)(GLR >1.88)與成巖作用區(qū)(GLR <1.88),這是一個新的發(fā)現(xiàn)(圖3)。
晶格應變是一個重要的影響衍射峰寬化的因素,因此對伊利石結晶度會產(chǎn)生相應的影響。已經(jīng)有眾多的學者對此發(fā)表了許多的文章討論晶格應變及其對伊利石結晶度的影響(Zulauf et al.,2002;árkai et al.,1997;Jiang et al.,1997;Merriman et al.,1995)。就伊利石結晶度而言,應變導致的衍射峰寬化效應應該去除,才可以得到準確的結晶度信息或Kübler 指數(shù)的真值。否則,結晶度和應變將共同作用于伊利石衍射峰的寬化效應,當應變寬化效應達到一定程度時,Kübler 指數(shù)描述的是礦物的粒度大小與應力引起的應變作用的混合效應。這偏離了Kübler 指數(shù)的原意:描述溫度引起的礦物生長的效應。HW-IR 圖解(Wang and Zhou,2000)和SHAPECT 軟件(Wang and Zhou,2005)用于分解粒度大小與應變大小對衍射峰的寬化效應,從而可以消除應變的影響。結果表明,應變值τ%達到小數(shù)點后1 位的樣品(HW-331,338)其對應的KI 指數(shù)也比相鄰樣品的KI 數(shù)值高(KI/τ% <2),其它樣品的KI/τ% >2。由此表明,較大的應變對KI 指數(shù)產(chǎn)生了有效的影響,而其它較小的應變對KI 指數(shù)產(chǎn)生的影響不大。
表2 綠泥石成分地質(zhì)溫度計數(shù)據(jù)(HW-324)Table 2 Data of chemical geothermometer of chlorite (HW-324)
由于綠泥石廣泛產(chǎn)于成巖和低溫變質(zhì)階段,其形成溫度可代表低溫變質(zhì)所產(chǎn)生的變質(zhì)溫度條件。因而,綠泥石地質(zhì)溫度計被應用在低溫變質(zhì)研究中。綠泥石地質(zhì)溫度計分為IV 占位溫度計和化學成分溫度計兩大類(Cathelineau,1988;Inoue et al.,2009;Hillier and Velde,1991;Xie et al.,1997;Vidal et al.,2001)。前者(以Cathelineau,1988 為代表)將溫度對綠泥石結構的影響表達為四面體中Al-Si 占位與形成溫度的關系,而后者(以Inoue et al.,2009 為代表)不僅考慮溫度與IV 中Al 占位的情況而且考慮了溫度與MgFeAl 在VI占位的情況。理論上,后者描述了溫度與綠泥石成分的全面關系,因此,近年來更受人們的“青睞”。本文即采用綠泥石成分地質(zhì)溫度計(公式18,Inoue et al.,2009)估算近變質(zhì)的溫度條件。結果約為260℃。詳細的數(shù)據(jù)見表2。
冷家溪群與其上的板溪群區(qū)域上呈現(xiàn)角度不整合關系,冷家溪群被當作變質(zhì)基底而板溪群及其上地層當作沉積蓋層是不少學者的觀點,這是地臺發(fā)展演化的模式。由于湖南跨越了揚子地臺和東南褶皺帶,因而,其橫向應該反映出地臺轉(zhuǎn)變?yōu)轳薨檸У淖兓Ρ纫延械某晒?湘西沅古坪,Wang et al.,2004;湘中黃土店,王河錦等,2003;湘東長沙-澧陵-瀏陽,朱明新和王河錦,2001;湘東北岳陽-臨湘,Wang et al.,2014),表明由北西向南東,變質(zhì)程度升高,即由近變質(zhì)轉(zhuǎn)變?yōu)闇\變質(zhì),變質(zhì)溫度由約260℃轉(zhuǎn)變?yōu)榧s360℃。這種變化反映出了湖南大地構造位子的特點。另外,板溪群和寒武紀黑色板巖的變質(zhì)表明了“沉積蓋層”的“活動”,似乎支持地臺再活動的地洼學說。而元古宇冷家溪群和板溪群的弱變質(zhì)則表明它們與大陸演化早期的“Greenvillian”事件(強烈陸-陸碰撞產(chǎn)生高級麻粒巖相變質(zhì))(Jamieson et al.,1992)關聯(lián)性小,揚子板塊與東南板塊之間的“碰撞”不“壯烈”,僅可能是“拼合”或“合并”。
(1)湘北中新元古宇及下古生界寒武系奧陶系遭受到了近變質(zhì)作用的影響,其變質(zhì)溫度約為260℃,具有中低壓變質(zhì)壓力類型特征。
(2)對數(shù)總成熟效應較好地描述了由成巖作用到變質(zhì)作用轉(zhuǎn)變過程中粘土礦物顆粒生長階段的差異變化。
(3)應力產(chǎn)生的礦物的應變在一定程度上可影響伊利石結晶度,從而產(chǎn)生對Kübler 指數(shù)的影響,并導致對成巖/變質(zhì)界限劃分的影響。
致謝 感謝蘇桂明高級工程師在電子探針測試給予的幫助。
árkai P,Balogh K and Frey M. 1997. The effects of tectonic strain on crystallinity,apparent mean crystallite size and lattice strain of phyllosilicates in low-temperature metamorphic rocks:A case study from the Glarus overthrust, Switzerland. Schweizerische Mineralogische und Petrographische Mitteilungen,77(1):27 -40
Bao ZX,Wan RJ and Bao JM. 1999. Metamorphic series of W-Sb-Au deposit in epimetamorphic rock series,western Hunan. Gold Geology,5(3):41 -47 (in Chinese with English abstract)
Bertaut EF. 1950. Raies de Debye-scherrer et repartition des dimensions des domaines de Bragg dans les poudres polycristallines. Acta Crystallographica,3(1):14 -18
Bove DJ, Eberl DD, McCarty DK and Meeker GP. 2002.Characterization and modeling of illite crystal particles and growth mechanisms in a zoned hydrothermal deposit,Lake City,Colorado.American Mineralogist,87(11 -12):1546 -1556
Brime C and Eberl DD. 2002. Growth mechanisms of low-grade illites based on shapes of crystal thickness distributions. Schweizerische Mineralogische und Petrographische Mitteilungen,82 (2):203-209
Bureau of Geology and Mineral Resources of Hunan Province (BGMRH).1988. Regional Geology of Hunan Province. Beijing:Geological Publishing House,6 -99 (in Chinese)
Bureau of Geology and Mineral Resources of Hunan Province. 1997.Stratigraphy (Lithostratic)of Hunan Province. Wuhan:China University of Geosciences Press,4 -122 (in Chinese)
Cathelineau M. 1988. Cation site occupancy in chlorites and illites as a function of temperature. Clay Minerals,23(4):471 -485
Che QJ,Wu GY,Tang XS and Peng HQ. 2005. Disintegration of Mesoproterooic Lengjiaxi Group in Northeast Hunan Province.Geology and Mineral Resources of South China,(1):47 -53,71(in Chinese with English abstract)
Dong H and Peacor DR. 1996. TEM observations of coherent stacking relations in smectite,I/S and illite of shales:Evidence for MacEwan crystallites and dominance of 2M1 polytypism. Clays and Clay Minerals,44(2):257 -275
Drits V,Srodon J and Eberl DD. 1997. XRD measurement of mean crystallite thickness of illite and illite/smectite:Reappraisal of the Kubler index and the Scherrer equation. Clays and Clay Minerals,45(3):461 -475
Eberl DD,Srodon J,Kralik M,Taylor BE and Peterman ZE. 1990.Ostwald ripening of clays and metamorphic minerals. Science,248(4954):474 -477
Eberl DD,Drits V,Irodo J and Nüesch R. 1996. MudMaster:A Program for Calculating Crystallite Size Distributions and Strain from the Shapes of X-ray Diffraction Peaks. U. S. Geological Survey Open File Report,96 -171
Frey M. 1987. Very low-grade metamorphism of clastic sedimentary rocks. In:Frey M (ed.). Low Temperature Metamorphism.Glasgaw and London:Blackie,9 -58
Frey M and Robinson D. 1999. Low-temperature metamorphism:An overview. In: Frey M and Robinson D (ed.). Low-grade Metamorphism. London:Blackwell Science,1 -9
Gao LZ,Chen J,Ding XZ,Liu YR,Zhang CH,Zhang H,Liu YX,Pang WH and Zhang YH. 2011. Zircon SHRIMP U-Pb dating of the tuff bed of Lengjiaxi and Banxi groups,northeastern Hunan:Constraints on the Wuling Movement. Geological Bulletin of China,30(7):1001 -1008 (in Chinese with English abstract)
Guidotti CV and Sassi FP. 1976. Muscovite as a petrogenetic indicator in pelitic schists. Neues Jahrbuch für Mineralogie Abhandlungen,127(2):97 -142
Guidotti CV and Sassi FP. 1986. Classification and correlation of metamorphic facies series by means of muscovite b0 data from lowgrade metapelites. Neues Jahrbuch für Mineralogie Abhandlungen,153(3):363 -380
Hillier S and Velde B. 1991. Octahedral occupancy and the chemical composition of diagenetic (low-temperature ) chlorites. Clay Minerals,26(2):149 -168
Hou GJ and Suo ST. 1996. Study of relation between Au-deposit and metacomplex rocks in Woxi, western Hunan. Journal of Geomechanics,2(3):43 -44 (in Chinese)
Inoue A,Meunier A,Patrier-Mas P,Rigault C,Beaufort D and Vieillard P. 2009. Application of chemical geothermometry to low-temperature trioctahedral chlorites. Clays and Clay Minerals,57(3):371 -382
Jamieson RA,Culshaw NG,Wodicka N,Corrigan D and Ketchum JWF.1992. Timing and tectonic setting of Grenvillian metamorphism:Constraints from a transect along Georgian bay,Ontario. Journal of Metamorphic Geology,10(3):321 -332
Jia BH. 1995. Features of Minoscale structure in epimetamorphic rock at the Lengjiaxi Group,Wenjiashi,border between Hunan and Jiangxi provinces. Geology of Jiangxi,9(3):169 -176 (in Chinese)
Jiang WT,Peacor DR,árkai P,Toth M,Kim JW. 1997. TEM and XRD determination of crystallite size and lattice strain as a function of illite crystallinity in pelitic rocks. Journal of Metamorphic Geology,15(2):267 -281
Jin WS and Sun DZ. 1997. Texture and Evaluation in Deep Crust of the Continent in the South of China. Beijing:Geological Publishing House,4 -22 (in Chinese)
Kisch HJ. 1991. Illite crystallinity: Recommendations on sample preparation,X-ray diffraction settings,and interlaboratory samples.Journal of Metamorphic Geology,9(6):665 -670
Kübler B. 1964. Les argiles,indicateurs de métamorphisme. Pevue Instituté de la Fran?ais Pétrole,19:1093 -1112
Langford JI,Louer D and Scardi P. 2000. Effect of a crystallite size distribution on X-ray diffraction line profiles and whole-powderpattern fitting. Journal of Applied crystallography,33(2):964-974
Liu HC and Zhu BQ. 1994. Study on the formation times of the Lengjiaxi and Banxi groups. Chinese Science Bulletin,39(2):148 -150 (in Chinese)
Lu LZ. 1988. The feature of metamorphic rock series of various age and metamorphic megacycles in China. In:Dong SB and Shen QH(eds.). Contribution to Compilation and Study of Metamorphic Map of China (2). Beijing:Geological Publishing House,1 - 9 (in Chinese)
Ma LF. 2002. Geological Atlas of China. Beijing:Geological Publishing House,245 -251 (in Chinese with English abstract)
M?hlmann RF. 1996. The pattern of diagenesis and metamorphism by vitrinite reflectance and illite“crystallinity”in Mittelbunden and in the Oberhalbstein. 2. Correlation of coal petrographical and of mineralogical parameters. Schweizerische Mineralogische und Petrographische Mitteilungen,76(1):23 -46
Maxwell DT and Hower J. 1967. High grade diagenesis and low-grade metamorphism of illite in the Precambrian belt series. American Mineralogist,52(5 -6):843 -857
Meng QX,Zhang J,Geng JZ,Zhang CL and Huang WC. 2013. Zircon U-Pb age and Hf isotope compositions of Lengjiaxi and Baxi groups in middle Hunan Province:Implications for the Neoproterozoic tectonic evolution in South China. Geology of China,40(1):197 -222 (in Chinese with English abstract)
Merriman RJ and Roberts B. 1985. A survey of white mica crystallinity and polytypes in pelitic rocks of Snowonia and Lly^n,North Wales.Mineralogical Magazine,49(352):305 -319
Merriman RJ,Roberts B,Peacor DR and Hirons SR. 1995. Strainrelated differences in the crystal growth of white mica and chlorite:A TEM and XRD study of the development of metapelitic microfabrics in the southern uplands thrust terrane, Scotland. Journal of Metamorphic Geology,13(5):559 -576
Merriman RJ and Peacor DR. 1999. Very low-grade metampelites:Mineralogy,microfabrics and measuring reaction progress. In:Frey M and Robinson D (eds.). Low Grade Metamorphism. Oxford:Blackwell,10 -60
Mullis J,Rahn MK,Schwer P,de Capitani C,Stern WB and Frey M.2002. Correlation of fluid inclusion temperatures with illite crystallinity data and clay mineral chemistry in sedimentary rocks from the external part of the Central Alps. Schweizerische Mineralogische und Petrographische Mitteilungen,82 (2):325-340
Rahn M, Mullis J, Erdelbrock K and Frey M. 1995. Alpine metamorphism in the north Helvetic flysch of the Glarus Alps,Switzerland. Eclogae Geologicae Helvetiae,88(1):157 -178
Sassi FP and Scolai A. 1974. The b0 value of the potassic white micas as a barometric indicator in low-grade metamorphism of pelitic schists.Contributions to Mineralogy and Petrology,45(2):143 -152
Schmidt D,Schmidt ST,Mullis J,M?hlmann RF and Frey M. 1997.Very low grade metamorphism of the Taveyanne formation of western Switzerland. Contributions to Mineralogy and Petrology,129(4):385 -403
Sun HQ,Huang JZ,Guo LQ and Chen J. 2012. Subdivision and isotopic age of Lengjiaxi Group in Hunan Province. Geology and Mineral Resources of South China,28 (1):20 - 26 (in Chinese with English abstract)
Vidal O,Parra T and Trotet F. 2001. A thermodynamic model for Fe-Mg aluminous chlorite using data from phase equilibrium experiments and natural pelitic assemblages in the 100 to 600℃,1 to 25kb range. American Journal of Science,301(6):557 -592
Wang H and Zhou J. 2000. The relationships between the Kübler index,Weaver index and Weber index of illite crystallinity and their applications. Schweizerische Mineralogische und Petrographische Mitteilungen,80(2):187 -198
Wang H,Zhou J,Wang L,Zhou Z and Yuan L. 2014. Diagenesis and metamorphism of the Meso-Neoproterozoic and the Lower Paleozoic along profile Yueyang-Linxiang in northeastern Hunan Province,China. Dresden, Germany: Abstract of 7thMid-European Clay Conference
Wang HJ,Zhou J,Xu QS,Liu CX and Zhu MX. 2002. Very low-grade metamorphism of the Meso-Neoproterozoic and the Lower Paleozoic along the profile from Huantudian to Xianxi in the central-northern part of Hunan Province,China. Science in China (Series D),32(9):742 -750 (in Chinese)
Wang HJ,Chen T,Wang H and Zhang ZQ. 2004. Anchimetamorphism of the Neoproterozoic and the Lower Paleozoic along the Profile of Yuanguping in western Hunan Province,China. Acta Geologica Sinica,78(1):170 -176
Wang HJ and Zhou J. 2005. Numerical conversion between the Pearson VII and pseudo-Voigt functions. Journal of Applied Crystallography,38:830 -832
Warren BE and Averbach BL. 1950. The effect of cold-work distortion on X-ray patterns. Journal of Applied Physics,21(6):595 -599
Wu GY,Li JD,Tang XS,Huang JZ,Xiao QH,Che QJ and Peng HQ.2005. Mineralogy,petrology and geochemistry of the Neoarchean metasedimentary-volcanic rocks at Jixichong,northeastern Hunan.Geology of China,32 (1):82 - 89 (in Chinese with English abstract)
Wu XH,Ling CF,Jiang CY and Li DM. 1965. Primary study of the metasedimentary-volcanic rocks in the Upper Banxi Group,eastern Guizhou Province. Geological Review,23 (1):54 - 60 (in Chinese)
Xie XG,Byerly GR,F(xiàn)errell Jr RE. 1997. IIb trioctahedral chlorite from the Barberton greenstone belt:Crystal structure and rock composition constraints with implications to geothermometry. Contributions to Mineralogy and Petrology,126(3):275 -291
Ylagan RF,Altaner SP and Pozzuoli A. 1996. Hydrothermal alteration of a rhyolitic hyaloclastite from Ponza Island, Italy. Journal of Volcanology and Geothermal Research,74(3 -4):215 -231
Yoder HS and Eugster HP. 1955. Synthetic and natural muscovites.Geochimica et Cosmochimica Acta,8(5 -6):225 -242,IN1-IN2,243-258,IN3,259 -280
Yu SC. 1987. Characteristics of the meta-volcanic rocks of Fengxijiang in Longhui County. Geology of Hunan,6(1):28 -34 (in Chinese with English abstract)
Zhu MX and Wang HJ. 2001. Very low-grade metamorphism of the Lengjiaxi and Banxi groups around the area of Changsha-Liling-Liuyang,Hunan Province,China. Acta Petrologica Sinica,17(2):291 -300 (in Chinese with English abstract)
Zulauf G,Kowalczyk G,Krahl J,Petschick R and Schwanz S. 2002.The tectonometamorphic evolution of high-pressure low-temperature metamorphic rocks of eastern Crete,Greece:Constraints from microfabrics,strain,illite crystallinity and paleodifferential stress.Journal of Structural Geology,24(11):1805 -1828
附中文參考文獻
鮑振襄,萬容江,鮑玨敏. 1999. 湘西淺變質(zhì)巖系中鎢銻金礦床成礦系列. 黃金地質(zhì),5(3):41 -47
車勤建,伍光英,唐曉珊,彭和求. 2005. 湘東北中元古代冷家溪群的解體及其地質(zhì)意義. 華南地質(zhì)與礦產(chǎn),(1):47 -53,71
高林志,陳峻,丁孝忠,劉耀榮,張傳恒,張恒,劉燕學,龐維華,張玉海. 2011. 湘東北岳陽地區(qū)冷家溪群和板溪群凝灰?guī)rSHRIMP鋯石U-Pb 年齡——對武陵運動的制約. 地質(zhì)通報,30(7):1001 -1008
湖南省地質(zhì)礦產(chǎn)局. 1988. 湖南省區(qū)域地質(zhì)志. 北京:地質(zhì)出版社,6 -99
湖南省地質(zhì)礦產(chǎn)局. 1997. 湖南省巖石地層. 武漢:中國地質(zhì)大學出版社,4 -122
候光久,索書田. 1996. 湘西沃溪變質(zhì)核雜巖與金礦關系研究. 地質(zhì)力學學報,2(3):43 -44
賈寶華. 1995. 湘贛邊境文家市一帶冷家溪群淺變質(zhì)巖小構造特征.江西地質(zhì),9(3):169 -176
金文山,孫大中. 1997. 華南大陸深部地殼結構及其演化. 北京:地質(zhì)出版社,4 -22
劉海臣,朱炳泉. 1994. 湘西板溪群及冷家溪群的時代研究. 科學通報,39(2):148 -150
盧良兆. 1987. 中國各時代變質(zhì)巖系及變質(zhì)巨旋回的特點. 見:董申保,沈其韓編.中國變質(zhì)地質(zhì)圖編圖論文集. 北京:地質(zhì)出版社,1 -9
馬麗芳. 2002. 中國地質(zhì)圖集. 北京:地質(zhì)出版社,245 -251
孟慶秀,張健,耿建珍,張傳林,黃文成. 2013. 湘中地區(qū)冷家溪群和板溪群鋯石U-Pb 年齡、Hf 同位素特征及對華南新元古代構造演化的意義. 中國地質(zhì),40(1):197 -222
孫海清,黃建中,郭樂群,陳俊. 2012. 湖南冷家溪群劃分及同位素年齡約束. 華南地質(zhì)與礦產(chǎn),28(1):20 -26
王河錦,周健,徐慶生,劉楚雄,朱明新. 2002. 湘中北黃土店-仙溪中新元古界-下古生界的甚低級變質(zhì)作用. 中國科學(D 輯),32(9):742 -750
伍光英,李金冬,唐曉珊,黃建中,肖慶輝,車勤建,彭和求. 2005.湘東北澗溪沖新太古代變質(zhì)沉積-火山巖巖石礦物學和巖石地球化學研究. 中國地質(zhì),32(1):82 -89
吳雪華,凌長富,江朝洋,李德明. 1965. 黔東上板溪羣地層中變質(zhì)火山碎屑巖的初步認識. 地質(zhì)論評,23(1):54 -60
喻水純. 1987. 隆回縣楓溪江變質(zhì)火山巖特征. 湖南地質(zhì),6(1):28-34
朱明新,王河錦. 2001. 長沙-澧陵-瀏陽一帶冷家溪群及板溪群的甚低級變質(zhì)作用. 巖石學報,17(2):291 -300