大别山超高压变质带面理化榴辉岩中变形石榴石的几何学和运动学特征及其大地构造意义

大别山东部双河附近面理化榴辉岩中, 所有榴辉岩相矿物包括石榴石、绿辉石乃至金红石都受到强烈拉伸。用透射电镜可以观察到石榴石晶体中塑性变形的显微构造, 包括自由位错、位错环、位错壁和位错网。拉伸石榴石的应变轴比表现为 Ｘ＞ Ｙ＞ Ｚ。运动学标志如石榴石的不对称碎斑和旋转的金红石颗粒, 表明有旋转应变的作用。石榴石和金红石的福林系数分别为１１８ 和０９８。所有这些都表明石榴石是在接近于平面应变的条件下形成。由于石榴石颗粒在应变前后体积未变,因此也是在简单剪切作用条件下形成的。根据石榴石韧性变形要求的温度条件, 此种变形应在榴辉岩相条件下发生, 代表一次向南的逆冲作用, 经过展开后, 逆冲的方向为南西。根据石榴石的流变律, 其韧性变形的最低温度估计约为 ８００℃。石榴石中普遍有一组透入性破劈理, 它产生于面理化榴辉石折返后的角闪岩相早期, 形成于石榴石韧性变形之后。破劈理及其中反Ｓ形破劈理的运动指向表明有向北的滑动, 发生在主簿源复背斜形成之前; 主簿源复背斜使面理化榴辉岩的产状由倾向北改变为倾向南。根据面理化榴辉岩及其围岩的同位素年龄, 估算出面理化榴辉岩在２００～１９０ Ｍａ 期间的平均垂直折返速率为９ｍ ｍ ／ａ。此外, 还     

大别山超高压变质带面理化榴辉岩石变形石榴石的几何学和运动学特 …

大别山东部双河附近面理化榴辉岩中,所有榴辉岩相矿物包括石榴石、绿辉石乃至金红石都受到强烈拉伸。用透射电镜可以观测到石榴石晶体中塑性变形的显微构造,包括自由位错、位错壁和位错网。拉伸石榴石的应变轴比表现为Ｘ〉Ｙ〉Ｚ。运动学标志如石榴石不对称碎斑和旋转的金红石颗粒,表明有旋转应变的作用。石榴石和金红石的福林系数分别为１．１８和０．９８。所有这些都表明石榴石在接近于平面应变的条件下形成。由于石榴石颗粒在     

大别山双河地区超高压变质岩矿物超微构造的HRTEM研究

报道了大别山双河地区超高压榴辉岩和硬玉石英岩矿物超微构造及缺陷结构的高分辨透射电镜研究结果。在天然变形绿辉石晶内的自由位错、位错倾斜壁、位错环、位错网、亚晶界、堆垛层错等亚构造中 ,发现了纳米级水分子团 ,这种球形状水分子团包体的存在是导致绿辉石晶体水解弱化和塑性变形的重要因素。在榴辉岩矿物中广泛发育的层错、(10 0 )变形双晶、晶畴结构、界面与晶面的交叉滑移、晶格畸变等变形构造及缺陷结构 ,指示超高压岩石经历了快速折返。在硬玉单晶大约 5 0 0nm的微晶畴内 ,发现了C2 /c和P2 1/n两种结构 ,C2 /c结构的晶体学参数对应于硬玉 ,而P2 1/n结构的晶体学参数对应于绿辉石 ,纳米级P2 1/n出溶结构的存在 ,表明在退变质过程中 ,硬玉在纳米尺度上部分转变为绿辉石 ,并且未能达到平衡。也说明在主体岩石的抬升过程中 ,硬玉晶体伴随有复杂的非平衡退变质作用。对于大别山超高压变质岩的p T轨迹描述及其构造解释具有重要意义。     

榴辉岩组构运动学与大陆深俯冲——中国大陆科学钻探主孔榴辉岩的EBSD研究

中国大陆科学钻探主孔位于苏鲁超高压带南部的东海县毛北榴辉岩体之上。主孔0-600米深度的榴辉岩的塑性变形以具中等倾角的东倾面理,近南北向的水平拉伸线理、“A”型剪切褶皱和一系列平行面理的微型韧性剪切带为特征。使用电子背散射（EBSD）技术测量的主孔7个榴辉岩样品的石榴石和绿辉石的晶格优选定向（LPO）表明：石榴石基本上无序排列,而绿辉石表现出强烈的LPO。绿辉石的[001]轴近平行于拉伸线理方向,（010）面的法线和[100]轴垂直面理分布,{110}的法线形成垂直面理的环带,反映绿辉石的位错蠕变由[001]（100）和1／2〈^-110〉滑移系控制,其不对称的LPO指示了由北向南的剪切指向。根据单斜辉石的高温实验结果,毛北榴辉岩经历了800-900℃的超高压变质作用。通过构造重塑,揭示毛北榴辉岩体为剪切流变褶皱,形成于扬子板块深俯冲时的超高压变质过程。因此榴辉岩中保留的早期岩石组构特征可以为板块的深俯冲运动学和俯冲极性提供重要信息。     

超高压榴辉岩中金红石的纳米级微构造特征及成因机制探讨

本文应用透射电子显微镜(TEM)详细研究了,中国苏鲁毛北地区金红石榴辉岩中金红石的超微构造特征。在该金红石榴辉岩中发育有两种不同类型的金红石晶体。第一种类型的金红石(Rt(A))与石榴石和绿辉石共生,其晶体内部发育有极密集的晶体缺陷,调制结构和变形双晶。变形双晶面分别为(100)和(010)。表明该类金红石晶体曾遭受过强烈的应力作用,推测它们可能是在大陆板块俯冲或折返过程中形成中发育的。而另一类金红石(Rt(B))存在于石榴石和绿辉石晶体中的包体,其晶格十分完整,没有变形痕迹。可能是由于该类金红石寄主于较大颗粒的石榴石或绿辉石晶体中,在大陆板块俯冲或折返过程中因受到寄住主晶的保护,没有发生晶格畸变。     

山东青岛、日照首次发现不同期榴辉岩

苏鲁地区榴辉岩呈大小不等的透镜状、团块状或不规则状赋存于超基性岩、片麻岩、大理岩和石英片岩中。作者于1993年在青岛市仰口和日照市梭罗树首次发现了两期榴辉岩。仰口榴辉岩体露头面积约100m~2,边缘有少量蛇纹岩伴生,围岩为花岗质片麻岩。岩体与围岩位于韧性变形带内,二者均受褶皱,并强烈糜棱岩化,被晚期(燕山期)花岗质脉体穿切。第一期为片麻状中粗粒榴辉岩,是主体岩性,片麻理走向近南北向。除局部保存较好外,绝大多数已被后期退变质作用所改造,新生的角闪石和斜长石成为主要矿物,少数石榴石呈斑状残留,新生片麻理与原始     

含柯石英榴辉岩形成深度的构造校正测算

应用透射电子显微镜(TEM)对大别地区英山县含柯石英榴辉岩、石英榴辉岩及石榴角闪岩中石榴子石进行研究,结果表明在强塑性变形的三类岩石中,石榴子石的超微构造特征存在明显差异。在含柯石英榴辉岩中的石榴子石位错密度比角闪岩中的低。修正石榴子石材料系数α为0.25,用石榴子石位错密度估算了相对差异应力值,并讨论了在超高压榴辉岩形成和退变质过程中各阶段的变质条件。根据石榴子石位错密度测定的差异应力,结合石榴子石的变形测量,恢复构造三维主应力及构造附加静水压力值P_S,从柯石英相的转变压力P中减去构造附加静水压力值P_S后,利用单纯由重力引起的静水压力值P_G换算上覆岩石的重力和厚度,获得大别超高压变质带含柯石英榴辉岩形成深度仅为 ≥ 32.09~32.11km.因此提出,该含柯石英榴辉岩是在这一地壳深处(或稍深一些)受强烈构造作用形成的新认识。同位素资料分析表明,大别地区榴辉岩系地壳成因,这对于榴辉岩是壳内产物的认识提供了进一步证据。      

超高压榴辉岩中绿辉石组构和变形机制研究进展

榴辉岩中绿辉石晶格优选方位(LPO)类型主要有S型(压扁型)组构、L型(收缩型)组构、L-S中间型组构、退火型组构,其中L型和S型组构是绿辉石在超高压岩石中最发育的组构类型.矿物组构的产生与变形机制密切相关,目前还无法解释绿辉石LPO产生和变化的原因.对天然绿辉石变形机制的最新研究进行了评述,包括位错蠕变产生变形绿辉石LPO的传统观点,以及扩散蠕变伴随晶体各向异性生长和空间群转换两种新观点.使用费氏台对大别山双河地区榴辉岩中的绿辉石组构进行了测量,并用电子背散射衍射技术(EBSD)对测量结果进行了验证.结合榴辉岩的显微构造和绿辉石组构特征对大别山双河超高压榴辉岩中绿辉石的变形机制进行了初步探讨,认为其变形机制以位错蠕变为主.     

石榴石流变学研究的某些进展

简要概述了近年来石榴石的晶体结构,高温高压实验,显微构造及其变形机制等领域的研究现状和进展;结合大别山榴辉岩的研究成果,着重讨论了石榴石的变形机制及其运动学特征,认为大别山燕窝榴辉岩中的石榴石经受了两期变形作用;早期变形是在榴辉岩相条件下,表现为塑性变形,其变形机制为简单剪切;而晚期变形则发生在角闪岩相条件下,表现为脆性变形的特点。     

大别—苏鲁超高压变质带内的块状榴辉岩及其构造意义

大别—苏鲁超高压(> 27× 108Pa) 变质带内的榴辉岩, 在大陆深俯冲、碰撞和折返剥露过程中, 大都遭受了强烈的变形和变质作用的重置与再造.但是, 大型榴辉岩体核部以及包裹于大理岩和石榴橄榄岩体内部的块状榴辉岩, 往往保留其初始简单的矿物组合、中-细粒状变晶结构和块状构造.详细地分析了块状榴辉岩的几何学、岩相学及变质作用特征, 指出它们是超高压榴辉岩递进及多期变质变形分解作用的残留体, 位于尺度不同的弱应变域内, 是大陆深俯冲及碰撞作用的真正记录.      

Structure analysis of geopolymers synthesized from clay originated from Serbia

The paper presents chemical and structural analysis of geopolymer materials which are obtained by alkali-activated calcined clay (metakaolin) originated from Serbia under strictly defined conditions. Characterization of the metakaolin and geopolymers molecular structure has been done using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The paper presents the possibility of obtaining geopolymer structure and differences in chemical and structural characterization of these materials taking into account the concentration of NaOH as a variable parameter. The results of MALDI analysis of metakaolin and synthesized geopolymer structures using various matrix system: 2,4,6 trihydroxyacetophenone (THAP), α-cyano-4-hydroxycinnamic, 2,6 dihydroxyacetophenone and laser desorption/ionization, have shown that THAP matrix is the most appropriate for analysing these aluminosilicate materials.     

Genesis of melilitolite from Colle Fabbri: inferences from melt inclusions

Melilite and wollastonite from the Colle Fabbri stock contain silicate melt and silicate-carbonate inclusions. The homogenization temperatures of silicate inclusions are within the magmatic temperature range of mantle ultrabasic melts: about 1,320?±?15 °С. Their composition is melilititic and evolves to the composition of leucite tephrite and phonolite. The composition of silicate-carbonate inclusions are high SiO₂, Ca-rich, enriched in alkalies and are similar to that of inclusions of carbonatite melts in the minerals of melilitolites of other intrusive ultramafic complexes. They are also similar to the compositions of metasomatized travertine covering the melilitolite stock. The presence of primary silicate and silicate-carbonate inclusions evidences that the melilitite magma from which melilitolites of Colle Fabbri crystallized was associated with carbonatite liquid. This liquid was highly fluidized, mobile and aggressive. Actively interacting with overlying travertine, the liquid enriched them with alkalies, aluminosilicates and incompatible elements, which resulted in the equalization of their compositions. Heterogeneous compositional dominions were formed at the contact between melilitolite and wall pelites. In the minerals of these contact facies high-Si melt inclusions of varying composition have been observed. Their occurrence is related to the local assimilation by the high-temperature melilitite magma of pelitic country rocks. The content of incompatible elements in melilitite melts and melilitolites is higher than the mantle norm and they have peculiar indicator ratios, spectra, Eu/Eu^* ratio, which suggest a peculiar mantle source.     

The characteristics of glacial tills from Northern England derived from a relational database

Geotechnical investigations have been carried out for many years in order to identify the depth, extent and the properties of the glacial deposits of Northern England. This valuable source of data exists in various forms because of the differences in the design of the investigations, the codes of practice relevant at the time of investigations, and contractors practice. An electronic store of these data would be a valuable asset not only to future development but to help in scientific studies of glacial till. This paper presents an overview of NETDATA (Northern England Till DATA), a relational database which is designed to store that data in a consistent format, allowing flexibility for further use. A preliminary analysis of the data has resulted in a characteristic data set for the tills.     

Chemistry of petroleum brines from oil-producing wells in Cretaceous rocks from Southeast Mexico

Brine chemical data obtained from oil wells in Cretaceous oilfields in the Southeastern Basin of Mexico show a complex evolution, with the following main hydrochemical processes: (1) mixing of highly evaporated brines, past the point of halite precipitation with seawater; (2) water/rock interactions between brines and carbonated rocks (dolostones).     

Mechanism of Mineral Reactions Inferred from Textures of Impure Dolomitic Marbles from East Greenland

Mineral assemblages and chemical compositions of minerals foundin impure dolomitic marbles embedded in gneisses and migmatitesof the E. Greenland Caledonian fold belt (Scoresby Sund) suggestthat the marbles were metamorphosed near 630 °C at 5 kbpressure. The analysis of complex textural and mineralogicalrelations among minerals such as dolomite, calcite, forsterite,pargasite, chlorite, spinel, diopside and phlogopite led tothe conclusion that the major mineralogical features of therocks were probably caused by sodium metasomatism at constanttemperature and pressure. The effect of the inferred sodiummetasomatism may be summarized by three schematic reactionsall involving modal changes of excess dolomite, calcite, forsterite,chlorite and spinel: (a) nucleation and growth of pargasite,(b) resorption of phlogopite, and (c) growth of pargasite fromphlogopite.     

Rheological Strength of UHP Eclogite from Dabieshan: Evidences from High p-T Experiments

ＴｈｅｈｙｐｏｔｈｅｓｉｓｏｆｔｒａｎｓｆｏｒｍａｔｉｏｎｏｆｂａｓａｌｔｔｏｅｃｌｏｇｉｔｅａｔｔｈｅｃｏｎｔｉｎｅｎｔａｌＭｏｈｏｄｉｓｃｏｎｔｉｎｕｉｔｙｉｎ 196 0ｓｅｖｅｒｂｒｏｕｇｈｔｂｒｏａｄｉｎｔｅｒｅｓｔｓｔｏｇｅｏｓｃｉｅｎｃｅｃｏｍｍｕｎｉｔｙ (ＲｉｎｇｗｏｏｄａｎｄＧｒｅｅｎ ,1996 ;ＧｒｅｅｎａｎｄＲｉｎｇｗｏｏｄ ,1972 ;ＩｔｏａｎｄＫｅｎｎｅｄｙ ,1971;ＫｕｓｈｉｒｏａｎｄＡｏｋｉ,196 8) .Ｔｈｉｒｔｙｙｅａｒｓｌａｔｅｒ ,ｗｉｔｈｔｈｅｄｉｓｃｏｖ ｅｒｉｅｓｏｆｃｏｅｓ…     

九连墩楚墓青铜器锈蚀产物的拉曼光谱分析

利用拉曼光谱对几件九连墩楚墓出土青铜器的腐蚀产物进行了测试。结果表明,九连墩楚墓出土的青铜器上主要的锈蚀产物为孔雀石[CuCO_3·Cu(OH)_2],存在部分蓝铜矿[2CuCO_3·Cu(OH)_2]和少许副氯铜矿[Cu_2(OH)_3Cl];此批青铜器锈蚀情况比较复杂,锈蚀种类比较丰富。在此基础上,探讨了科学保护此批青铜器的方法。     

Preparation of iron phosphate from sludge sourced from the electrocoagulation treatment of source-separated urine

In order to prepare iron phosphate by waste sludge, we report a method for effective utilization of the sludge obtained from the electrocoagulation treatment of source-separated urine. The sludge was dissolved with hydrochloric acid and pretreated with H₂O₂ and Na₃PO₄; finally, NaOH was added to precipitate iron phosphate from the solution. Thermal treatment of the precipitate at 750 °C in air yielded crystalline quartz-like anhydrous FePO₄. The precipitate was characterized by a number of thermal techniques such as thermogravimetry/differential thermal analysis, scanning electron microscopy, and X-ray powder diffraction.     

Thermoluminescence of carbonates from carbonatites

The Gejiu tin field in southern China consists of six major deposits and many minor ones containing more than 120 million tons (pre-mining resource) at 1% Sn and significant amounts of Cu, Ag, Zn, and Pb. It is one of the largest tin fields of primary deposits in the world. Mineralization is the result of the intrusion of granitic plutons into Permian and Triassic sedimentary rocks, which are dominantly limestone, dolomitic limestone, and dolomite. Five (mostly peraluminous) granitic intrusives (64-115 Ma) are present in the area. The largest orebodies are spatially and temporally related to the Laoka (principally), Beipaotai, and Marsong granites. Tin mineralization is mainly within greisens developed at the outermost zone of a skarn zonal sequence and are mineralogically dominated by fluorite, quartz, and micas.

The deposits are the result of volatile-rich ore solutions that evolved late in the plutonic crystallization history. The solutions produced metamorphic skarns as well as ore skarns, both of which later became “greisenized” skarns. Gejiu is the largest example of what has been, up to now, a style of mineralization reported only in minor amounts.     

Palaeoclimatic inferences from the behaviour of radiocarbon dates of carbonates from Sand Dunes of Rajasthan

Radiocarbon dates on pedogenic CaCO₃, accumulated at various depths in a stabilised dune at Budha Pushkar, Rajasthan, show inversion with respect to ‘stratigraphy’. Occurrence of younger carbonates overlain by older ones at various levels, is interpreted in terms of a shift in climatic conditions causing pedogenic carbonates to be leached to greater depths. Based on this model, several wetter regions during the last 6000 years have been identified. The most significant shift from a dry to a wet phase seems to have taken place between 5000 and 4500 years ago. Conclusions drawn from this study is in agreement with that based on pollen data and extends this method as a potential palaeoclimatic indicator.