共查询到20条相似文献，搜索用时 682 毫秒
1.
中国科学院西部地区南水北调综合考察队地质组 《地质科学》1960,3(5):241-241
1930年譚錫畴和李春昱在四川西部(原西康省)进行地貭調查吋,曾将康定以西的一套黑灰色板岩、頁岩和砂岩,以及綠灰色板岩和砂岩的地层命名为“西康系”,并在雅江以西地区采得植物化石。化石多为Podozamites,故将“西康系”与香溪煤系对比,并将它划归侏罗紀(見譚錫畴、李春昱,1959:四川西康地貭志)。黄汲清在1945年所著的“中国主要地貭构造单位”一书中,曾列举了五点証据,否定“西康系”为侏罗紀地层,并认为主要属古生代。在1955年所出的“康藏路线地貭图”中,将“西康系”地层另命名为“札科系”,将其时代定为二迭紀。1958年甘孜地貭队将它划为石炭二迭紀,另外亦有人将它定为石炭紀。总之,这套地层的时代,长期以來是爭論不休的。 相似文献
2.
3.
4.
5.
“仑山灰岩”标准地点在江苏南部句容县的仑山。1933年,俞建章在研究“仑山灰岩”中的头足类动物群时,曾指出:“仑山灰岩”的时代应属于早、中奥陶世。1935年,李捷等在系统研究宁镇山脉地质时,对“仑山灰岩”重新进行划分,把上部含鞘角石(Vaginoceras)动物群的灰岩归入中奥陶统,称汤山灰岩。 相似文献
6.
7.
概述雷公墨是一种天然玻璃,常称为“玻璃陨石”,因为自古以来多认为是从天空陨落的。“雷公墨”这个名称最早为十世纪中叶唐朝刘恂所采用。现在雷州半岛的群众都称之为“雷公屎”,可能是因为常在雷雨冲刷之后暴露于地表之故。 相似文献
8.
岩石中微量銻的測定,因受光譜分析的灵敏度的限制,一般采用比色法測定,其中一种是应用甲基紫进行比色。在地貭科学1960年第1期中刊登有陈增源所写“岩石及土壤中微量銻的快速比色测定”一文,在該文中已对这种方法作了介紹。 相似文献
9.
准噶尔盆地西北缘辫状河沉积模式探讨--以七区下侏罗统八道湾组辫状河沉积为例 总被引：1，自引：0，他引：1
准噶尔盆地西北缘下侏罗统下部地层主要发育辫状河沉积。以新疆油田七区下侏罗统八道湾组为例,以岩芯观察为基础,综合利用薄片鉴定、分析化验以及测井解释等资料,分析认为该区辫状河的沉积鉴别标志为:岩石类型比较单一;岩石成分复杂,成熟度较低,局部常见富集成层的碳屑;沉积构造丰富,具有“二元结构”;砂体具有“泛连通体”结构等。在此基础上,进一步从颜色、岩性、粒度、沉积构造和测井曲线特征等方面剖析了河床滞留、心滩和泛滥平原等微相的沉积特征,并结合沉积微相的空间分布规律,探讨了研究区的辫状河沉积模式。该研究成果对油田的滚动勘探和开发调整都具有重要意义。 相似文献
10.
青海石油管理局科学研究所岩矿研究室詹述星同志在配制成功“碘盐重液”的基础上,又进一步利用水银、碘化钾、碘及水配制成功又一种新的重液。这种重液,最大比重可达3:1,其效果性能、操作中应注意事项及重液的回收完全与“碘盐重液”相同。（参看石油勘探第13期:“自制碘盐重液”。）成本较碘盐重液还要便宜,降低达72％,每磅只需15.9元。药品也很容易买到。 相似文献
11.
Jim Watkins Michael Manga Christian Huber Michael Martin 《Contributions to Mineralogy and Petrology》2009,157(2):163-172
Spherulites are spherical clusters of radiating crystals that occur naturally in rhyolitic obsidian. The growth of spherulites
requires diffusion and uptake of crystal forming components from the host rhyolite melt or glass, and rejection of non-crystal
forming components from the crystallizing region. Water concentration profiles measured by synchrotron-source Fourier transform
spectroscopy reveal that water is expelled into the surrounding matrix during spherulite growth, and that it diffuses outward
ahead of the advancing crystalline front. We compare these profiles to models of water diffusion in rhyolite to estimate timescales
for spherulite growth. Using a diffusion-controlled growth law, we find that spherulites can grow on the order of days to
months at temperatures above the glass transition. The diffusion-controlled growth law also accounts for spherulite size distribution,
spherulite growth below the glass transition, and why spherulitic glasses are not completely devitrified.
An erratum to this article can be found at 相似文献
12.
斜长石是自然界最常见的造岩矿物,一般认为它是完全类质同象系列的典型代表。然而近代研究发现,斜长石在地质体中出现的概率是不均等的,呈不连续的众数分布。在斜长石的X射线衍射、电子衍射、光学性质以及红外吸收光谱所记录的相关曲线上,出现反映结构变化的不连续点,这些不连续点与上述稳定斜长石(呈众数者)的成分点一致。另外,斜长石的非布拉格“卫星”衍射等都说明斜长石超结构对斜长石的稳定性起着重要的制约作用。本文以大量的实际资料,把斜长石的内部结构和斜长石各种物理化学性质联系起来,讨论各种斜长石成分的分布规律,并提出低结构态斜长石分类。 相似文献
13.
一、引言铸石是利用天然岩石,如玄武岩、辉绿岩或某些工业废渣为原料,经配料或直接熔化、浇铸成型、结晶、退火而成的一种工艺岩石。它的矿物组分主要为单斜辉石,磁铁矿的量很少,在个别情况下可有少量橄榄石。从生产技术来看,铸石就是把天然玄武岩类所含的复杂矿物相用人工转变为单一矿物相,也就是将原料中大量的斜长石和相当量的橄榄石 相似文献
14.
P. L. Clay B. O’Driscoll R. Gertisser H. Busemann S. C. Sherlock S. P. Kelley 《Contributions to Mineralogy and Petrology》2013,165(2):373-395
Spherulitic textures in the Rocche Rosse obsidian flow (Lipari, Aeolian Islands, Italy) have been characterized through petrographic, crystal size distribution (CSD) and in situ major and volatile elemental analyses to assess the mode, temperature and timescales of spherulite formation. Bulk glass chemistry and spherulite chemistry analyzed along transects across the spherulite growth front/glass boundary reveal major-oxide and volatile (H2O, CO2, F, Cl and S) chemical variations and heterogeneities at a ≤5 μm scale. Numerous bulk volatile data in non-vesicular glass (spatially removed from spherulitic textures) reveal homogenous distributions of volatile concentrations: H2O (0.089 ± 0.012 wt%), F (950 ± 40 ppm) and Cl (4,100 ± 330 ppm), with CO2 and S consistently below detection limits suggesting either complete degassing of these volatiles or an originally volatile-poor melt. Volatile concentrations across the spherulite boundary and within the spherulitic textures are highly variable. These observations are consistent with diffusive expulsion of volatiles into melt, leaving a volatile-poor rim advancing ahead of anhydrous crystallite growth, which is envisaged to have had a pronounced effect on spherulite crystallization dynamics. Argon concentrations dissolved in the glass and spherulites differ by a factor of ~20, with Ar sequestered preferentially in the glass phase. Petrographic observation, CSD analysis, volatile and Ar data as well as diffusion modeling support continuous spherulite nucleation and growth starting at magmatic (emplacement) temperatures of ~790–825 °C and progressing through the glass transition temperature range (T g ~ 750–620 °C), being further modified in the solid state. We propose that nucleation and growth rate are isothermally constant, but vary between differing stages of spherulite growth with continued cooling from magmatic temperatures, such that there is an evolution from a high to a low rate of crystallization and low to high crystal nucleation. Based on the diffusion of H2O across these temperature ranges (~800–300 °C), timescales of spherulite crystallization occur on a timescale of ~4 days with further modification up to ~400 years (growth is prohibitively slow <400 °C and would become diffusion reliant). Selective deformation of spherulites supports a down-temperature continuum of spherulite formation in the Rocche Rosse obsidian; indeed, petrographic evidence suggests that high-strain zones may have catalyzed progressive nucleation and growth of further generations of spherulites during syn- and post-emplacement cooling. 相似文献
15.
16.
通过野外观察,结合薄片、铸体薄片等手段研究,发现海拉尔盆地呼伦湖凹陷西界上库力组火山通道相次火山亚相的柱状节理流纹岩和喷溢相上部亚相的球粒流纹岩中发育两种不同结构的球粒,两种球粒均形成于高的过冷却动力学效应下。柱状节理流纹岩中的球粒肉眼不可见,球粒直径小于0. 2 mm,球粒中心发育结晶核,组成球粒的纤维体多为隐晶质。条带状球粒流纹岩中的球粒在野外露头上醒目,圆形、椭圆形特征明显,球粒直径在0. 5～2 mm之间,均匀分布,结晶核不明显,组成球粒的纤维体为霏细质。本文认为导致这两种球粒结构差异性的主要原因是受熔浆过冷度大小的影响,柱状节理流纹岩过冷度较条带状球粒流纹岩大,因此成核速率高,成核密度大,球粒直径小,排列紧密,条带状球粒流纹岩较之相反。同时,流纹质熔浆的均质性程度影响了球粒间孔的充填特征。此外,研究发现,球粒间孔的发育程度和球粒形态直接相关。柱状节理流纹岩基质中的球粒结构紧密排列,球粒受相互生长制约呈不规则状,由于柱状节理本身由十分致密的球粒构成,储集空间不发育,因此不含油。由于条带状球粒流纹岩的球粒排列相对疏松,孔隙大量发育,可能含有丰富的油气,储集空间主要类型为球粒间孔和球粒溶蚀孔。 相似文献
17.
变质岩中的球状结构及其对变质作用的指示 总被引：1，自引：1，他引：0
球状结构是指由纤维状晶体组成的放射状集合体,其为一种高度不平衡的结构。它们常见于火山岩、假玄武玻璃、沉积岩以及热液沉积物中,在不同变质级别的变质岩中也有广泛报道。变质岩中的球状结构记录了丰富的变质作用信息,然而其在变质岩中的成因机制和对变质作用的指示意义尚缺少详细的研究。球状结构的生长需要温度、压力或成分的改变使得结晶体系远离平衡,它的结晶动力学过程受物质的扩散控制,要求晶体生长速率远大于物质扩散速率。详细解析球状结构和分析导致不平衡的因素有助于限定变质作用的条件和过程。本文拟从变质岩中报道的代表性球状结构出发,基于球状结构结晶所需的热力学和动力学条件,总结变质岩中球状结构的四种可能成因机制:流体结晶、变质熔体结晶、冲击变质作用和高度不平衡的变质反应。组成球状结构的纤维状晶体具有大的表面能,在持续保持温压和流体条件不变的情况下会快速重结晶使得球状结构消失,球状结构得以保留意味着其所处的环境要迅速转变为它不再结晶的条件。因此,变质岩中的球状结构指示寄主岩石经历了持续时间很短的非平衡变质作用过程。借鉴其它学科研究球状结构的定量方法和在变质作用条件下开展球状结构的实验研究是变质岩中球状结构研究的潜在方向。 相似文献
18.
无机晶体的折射率不仅取决于它的化学成分及内部构造,而且取决于离子的电子壳层结构。作者在研究氧离子最紧密堆积构造的矿物的折射率时,曾指出轻元素Be,Li,Al,Na,Mg(惰性气体结构类型的离子)起着同样的作用,具有d层价电子的过渡族元素Fe,Ti,Mn,Cr,Sc等有较大的折射率增量。 相似文献
19.
南海新生代碱性玄武岩中斜长石矿物的化学成分及意义 总被引：1，自引：0，他引：1
南海新生代碱性玄武岩中存在两种不同粒径的斜长石矿物.其一为斜长石斑晶,常见熔蚀麻点,是岩浆上升、压力降低时发生熔蚀作用并在骤冷条件下形成的;其二斜长石微晶,半定向或杂乱分布于火山玻璃中,其中空骸晶结构表明斜长石微晶是在淬冷条件下迅速结晶形成的.斜长石斑晶具弱成分环带,斑晶边部的An值稍高或接近于斜长石微晶.微晶斜长石An值与岩浆喷出后的水深以及喷发位置距离岩浆主通道的远近存在一定联系.本区的斜长石斑晶形成温度明显低于冲绳海槽地区,而类似于东海陆架地区;斜长石微晶的结晶温度类似于冲绳海槽,表明两地区在岩浆喷出海底后淬火结晶的物理化学条件相似.结合同样品中橄榄石斑晶研究结果以及已有的地球物理学和岩石学方面的资料,可能反映了地幔柱快速上涌使早期部分熔融及结晶分异作用较弱,岩浆本身温度高提供了早期结晶形成的斑晶与寄主岩浆进一步充分反应的热量.计算的斜长石斑晶温度不能反映源区温度特征,后者应高于本文所计算的斜长石斑晶的结晶温度. 相似文献
20.
Bulk chemistry and mineralogy of the peculiar rock of Ricetto (Carseolani Mts., Central Apennines, Italy) was studied to resolve its controversial origin: igneous dyke or anthropic product. This hybrid rock consists of a colorless, felsic component made up of glass plus quartz, and a brown, femic component made up of fans and spherulites of diopside, calcic plagioclase, wollastonite, and melilite. Textural relationships indicate very rapid cooling and immiscibility phenomena. The bulk chemistry of the rock is the same as that of the surrounding siliciclastic sandstone. The 14C analysis of a coal fragment from bottom of the body yields the conventional age of 227(±50) years. The Ricetto occurrence is an example of pyrometamorphism of a siliceous limestone induced by a charcoal pit burning. The small size of the heat source at Ricetto caused an intense but short-lived melting of the country rock. Prograde metamorphism caused a temperature increase up to 1,000–1,100 °C when melilite crystallization conditions were reached at appreciable P(CO2) and high f(O2). Melting occurred in a close system represented by the simplified equation: 3Cal+16.5Qtz+Ms+BtMel+Melt+2H2O+3CO2+0.5O2. Diopside+calcic plagioclase+wollastonite formed by melilite breakdown during rapid cooling, through the reaction: 6Mel+6Qtz+0.5O23Di+2An+7Wo. Liquid immiscibility caused the separation between the felsic melt component and the femic melilite-bearing component. Immiscibility was characterized by different fractionation of alumina and alkalies between these two phases. Differences in bulk, glass, and mineral chemistry between the Ricetto and other melilite-bearing pyrometamorphic rocks can be attributed mainly to different protoliths.An erratum to this article can be found at 相似文献