吐哈盆地侏罗系煤中超微类脂体特征和演化   总被引：3，自引：0，他引：3  

王飞宇  赵长毅 《煤田地质与勘探》1997,25(1):15-19

利用共聚焦激光显微镜和透射电镜对吐哈盆地侏罗系煤进行超微层次有机岩石学分析，发现微米级以下超微类脂体普遍存在于无结构镜质体和一些粗粒体之中。常规光学显微镜下难以分辨超微类脂体，在镜质体反射率Ｒｏ０．５０％￣０．７０％时，煤中超微类脂体数量一般为８％￣１２％。超微类脂体的光性演化明显领先于壳质组形态组分孢子体和角质体，它是吐哈侏罗系煤中重要的生油组分。  相似文献   

有机岩石学及其在油气评价中的应用   总被引：1，自引：0，他引：1  

肖贤明 《地球科学进展》1992,7(2):39-44

  简要介绍了有机岩石学研究方法的发展与特.点，系统的论述了这门新兴学科用于确定烃源岩成熟度、有机质类型，研究油气生成、运移与聚集等方面所取得的进展。
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Assessing thermal maturity of Palaeozoic rocks from reflectance of chitinozoa as constrained by geochemical indicators: an example from southern Ontario, Canada     

M. Obermajer  M.G. Fowler  F. Goodarzi  L.R. Snowdon 《Marine and Petroleum Geology》1996,13(8):907-919

The reflectance of chitinozoa (%ChR₀) was investigated as an alternative technique of determining the level of thermal maturity of organic-rich Palaeozoic rocks in southern Ontario. These sedimentary strata, which include the Ordovician Collingwood Member and the Blue Mountain Formation, as well as the Devonian Marcellus Formation, lack vitrinite precluding the application of a standard vitrinite reflectance (%VR₀) technique. ChR₀ shows a proportional increase at marginal to moderate maturities, being on average 20 to 25% higher than expected vitrinite reflectance. The reflectance data fall into a very narrow range showing a high degree of consistency for each lithostratigraphic unit. The average ChR₀ are as follows: Collingwood Mbr 0.63% (Georgian Bay area) and 0.88% (Toronto area), Blue Mountain Fm 0.92%, Marcellus Fm 0.68%. Correlation with more conventional optical and geochemical maturity parameters obtained from the same set of samples (fluorescence of Tasmanites, Leiosphaeridia and Gloeocapsomorpha alginite, Rock-Eval Tmax, extract data, distribution of terpanes and steranes in extracts) indicates that, within the area of study, the beginning of the catagenetic stage corresponds to ChR₀=0.65% (equivalent VR=0.50%) whereas the threshold of significant oil generation is reached at ChR₀=0.9% (equivalent VR=0.70%). Therefore the Blue Mountain Formation is thermally mature with respect to hydrocarbon generation throughout the whole area of study. The Collingwood shales are mature only in the Toronto area while those occurring in the Georgian Bay area as well as the Marcellus shales have yet to enter the main stage of hydrocarbon generation. This integrated approach of assessing thermal maturity shows that ChR₀, when constrained with other maturity parameters, is a very reliable indicator of thermal maturity in Lower to Middle Palaeozoic sedimentary rocks.  相似文献   

Submersible observations of Equatorial Atlantic mantle: The St. Paul Fracture Zone region     

Hekinian  R.  Juteau  T.  Gràcia  E.  Sichler  B.  Sichel  S.  Udintsev  G.  Apprioual  R.  Ligi  M. 《Marine Geophysical Researches》2000,21(6):529-560

The St. Paul F.Z. is a large structural domain made up of multiple transform faults interrupted by several Intra-Transform Ridge (ITR) spreading segments. Two regions were studied in details by submersible: (1) The ITR short (<20 km in length) segment near 0° 37N–25° 27W and 1° N–27° 42W and (2) The St. Peter and St. Paul's Rocks (SPPR) massif located at 29° 25W (¡3700 m depth). (1) The short ITR segments consist of a magma starved rift valley with recent volcanic activities at 4700 m depth. A geological profile made along the rift valley wall showed localized volcanics (basalts and dykes) which are believed to overlay and intrude the ultramafics. The geological setting and the high ultramafic/volcanic ratio suggest an extremely low magmatic supply and crustal-mantle uplift during lithospheric stretching and denudation. (2) The St. Peter and St. Paul's Rocks (SPPR) massif consists of a sigmoidal ridge within the active transform zone. The SPPR is divided into two different geological domains called the North and the South Ridges. The North Ridge consists of strongly tectonized fault scarps composed of banded and mylonitized peridotite, sporadic gabbros (3900–2500 m) and metabasalts (2700–1700 m). The South Ridge is less tectonized with undeformed, serpentinized spinel lherzolite (2000–1400 m) and basalts. Extensional motion and denudation accompanied by diapirism affected the South Ridge within a transform domain. Instead, the North Ridge was formed during an important strike-slip and faulting motion resulting in the uplifted portion of the St. Paul F.Z. transverse ridge. There is a regional compositional variation of the volcanics where E-MORBs and alkali basalts are produced on the SPPR massif and are comparable to the adjacent northern segments of the Mid-Atlantic Ridge. On the other hand, N and T- MORBs collected from the eastern part of the St. Paul F.Z. (25° 27W IRT) are similar to the volcanics from the southern segments of the MAR. The peridotites exposed in these provinces (SPPR and ITR) are similar in their REE and trace element distribution. Different degrees (3–15%) of partial melting of a mixed composite mantle consisting of spinel and amphibole bearing lherzolite veined with 5–40% clinopyroxenite gave rise to the observed MORBs and alkali basalts.  相似文献   

马里亚纳海槽玄武岩岩石学   总被引：3，自引：0，他引：3  

陈穗田  张德玉 《海洋地质与第四纪地质》1991,(3)

马里亚纳海槽岩石学的研究表明本区岩石属基性的玄武岩,又细分为洋底玄武岩(OFB)和钙碱玄武岩(CAB)。微量元素相对球粒陨石标准化数值特征:除了Sc、Ti,V外,其它过渡元素都有亏损,Cr、Ni出现了明显负异常,Ti相对较富集,稀土元素(REE)表现富集型的型式;同位素测试结果,εNd(0)=6.9。可以认为这些玄武岩是上幔岩的局部熔融形成的岩浆沿着扩张中心喷溢到海底,而形成的新生洋壳。  相似文献   

马里亚纳海槽热液区岩石矿物学和岩石化学特征研究     

吴世迎  刘焱光  李泽林  张德玉  张道建  王湘芹  白黎明  吴军瑞 《海洋科学进展》2001,19(4):22-29

马里亚纳海槽中央轴裂谷中的小扩张脊部位 ,广布火山喷发的玄武岩体 ,海底热液硫化物就是从这些岩体的裂隙中喷溢堆积起来的。利用我国“大洋一号”船拖网所获岩样进行了矿物学和岩石化学特征研究 ,认定为高铝低钾的大洋底玄武岩或拉斑玄武岩系列和钙 -碱玄武岩。为进一步弄清马里亚纳海槽区热液活动岩石学条件和探讨海槽区热液物质来源提供科学证据  相似文献   

Cathodoluminescence study of carbonate cements in the Upper Cambrian conglomerates from the Wonominta Block,northwestern New South Wales     

《Australian Journal of Earth Sciences》2013,60(2):247-259

Petrological studies were carried out on the Upper Cambrian conglomerates from the Bilpa and Cupala Creek areas, in the Wonominta Block, northwestern New South Wales. The sediments are post‐orogenic, molasse‐type, shaped in continental and shallow‐marine environments, and deposited in the form of major coarse‐grained deltas. Diagenetic processes caused an extensive lithification of these psephitic deposits. Multistage carbonate cementation is one of the most significant diagenetic changes that occurred. Several generations of carbonate cements have been distinguished based on observations under the polarising microscope, and particularly, using cathodoluminescence analysis. In both areas studied the conglomerates show four types of calcite cements under cathodoluminescence developed in the following order: non‐luminescent (+oscillatory zoned)‐bright orange‐dull orange‐(non‐luminescent). The most likely sequence of carbonate cementation is presented involving eo‐, meso‐ and telo‐ stages of diagenesis. Minor malachite crystallised along with calcite in the telodiagenetic stage.  相似文献   

Petrology and P–T evolution of garnet peridotites from central Sulawesi, Indonesia     

Kadarusman  & Parkinson 《Journal of Metamorphic Geology》2000,18(2):193-209.

Alpine‐type orogenic garnet‐bearing peridotites, associated with quartzo‐feldspathic gneisses of a 140–115 Ma high‐pressure/ultra‐high‐pressure metamorphic (HP‐UHPM) terrane, occur in two regions of the Indonesian island of Sulawesi. Both exposures are located within NW–SE‐trending strike–slip fault zones. Garnet lherzolite occurs as <10 m wide fault slices juxtaposed against Miocene granite in the left‐lateral Palu‐Koro (P‐K) fault valley, and as 10–30 m wide, fault‐bounded outcrops juxtaposed against gabbros and peridotites of the East Sulawesi ophiolite within the right‐lateral Ampana fault in the Bongka river (BR) valley. Six evolutionary stages of recrystallization can be recognized in the peridotites from both localities. Stage I, the precursor spinel lherzolite assemblage, is characterized by Ol+Cpx+Opx±Prg‐Amp ± Spl±Rt±Phl, as inclusions within garnet cores. Stage II, the main garnet lherzolite assemblage, consists of coarse‐grained Ol+Opx+Cpx+Grt; whereas finer‐grained, neoblastic Ol+Opx+Grt+Cpx±Spl±Prg‐Amp±Phl constitutes stage III. Stages IV and V are manifest as kelyphites of fibrous Opx+Cpx+Spl in inner coronas, and Opx+Spl+Prg‐Amp±Ep in outer coronas around garnet, respectively. The final (greenschist facies) retrogressive stage VI is accompanied by recrystallization of Serp+Chl±Mag±Tr±Ni sulphides±Tlc±Cal. P–T conditions of the hydrated precursor spinel lherzolite stage I were probably about 750 °C at 15–20 kbar. P–T determinations of the peak stage IIc (from core compositions) display considerable variation for samples derived from different outcrops, with clustering at 26–38 kbar, 1025–1210 °C (P‐K & BR); 19–21 kbar, 1070–1090 °C (P‐K), and 40–48 kbar, 1205–1290 °C (BR). Stage IIr (derived from rim compositions) generally records decompression of around 4–12 kbar accompanied by cooling of 50–240 °C from the IIc peak stage. Stage III, which post‐dates a phase of ductile deformation, yielded 22±2 kbar at 750±25 °C (P‐K) and 16±2 kbar at 730±40 °C (BR). The granulite–amphibolite–greenschist decompression sequence reflects uplift to upper crustal levels from conditions of 647–862 °C at P=15 kbar (stage IV), through 580–635 °C at P=10–12 kbar (stage V) to 350–400 °C at P=4–7 kbar (stage VI), respectively, and is identical to the sequence recorded in associated granulite, gneiss and eclogite. Sulawesi garnet peridotites are interpreted to represent minor components of the extensive HP‐UHP (peak P >28 kbar, peak T of c. 760 °C) metamorphic basement terrane, which was recrystallized and uplifted in a N‐dipping continental collision zone at the southern Sundaland margin in the mid‐Cretaceous. The low‐T , low‐P and metasomatized spinel lherzolite precursor to the garnet lherzolite probably represents mantle wedge rocks that were dragged down parallel to the slab–wedge interface in a subduction/collision zone by induced corner flow. Ductile tectonic incorporation into the underthrust continental crust from various depths along the interface probably occurred during the exhumation stage, and the garnet peridotites were subsequently uplifted within the HP‐UHPM nappe, suffering a similar decompression history to that experienced by the regional schists and gneisses. Final exhumation from upper crustal levels was clearly facilitated by entrainment in Neogene granitic plutons, and/or Oligocene trans‐tension in deep‐seated strike–slip fault zones.  相似文献   

Early Permian supra‐subduction assemblage of the South Island terrane,Percy Isles,New England Fold Belt,Queensland     

M. C. Bruce  Y. Niu 《Australian Journal of Earth Sciences》2013,60(6):1077-1085

Ultramafic‐intermediate rocks exposed on the South Island of the Percy Isles have been previously grouped into the ophiolitic Marlborough terrane of the northern New England Fold Belt. However, petrological, geochemical and geochronological data all suggest a different origin for the South Island rocks and a new terrane, the South Island terrane, is proposed. The South Island terrane rocks differ from ultramafic‐mafic rocks of the Marlborough terrane not only in lithological association, but also in geochemical features and age. These data demonstrate that the South Island terrane is genetically unrelated to the Marlborough terrane but developed in a supra‐subduction zone environment probably associated with an Early Permian oceanic arc. There is, however, a correlation between the South Island terrane rocks and intrusive units of the Marlborough ophiolite. This indicates that the two terranes were in relative proximity to one another during Early Permian times. A K/Ar age of 277 ± 7 Ma on a cumulative amphibole‐rich diorite from the South Island terrane suggests possible affinities with the Gympie and Berserker terranes of the northern New England Fold Belt.  相似文献   

大同矿区5#煤层煤岩煤质特征及其清洁利用方式     

赵彦  李春兰  张宁  孔庆虎 《中国煤炭地质》2022,(1)

大同矿区位于山西省大同市的西南,主要含煤地层为侏罗系大同组和石炭二叠系山西组、太原组,是我国典型的双纪煤田。在收集大同矿区以往勘查资料的基础上,系统分析了大同矿区5#煤层的煤岩煤质特征,煤质主要为中灰、高挥发分、中硫、高热稳定性煤,整体以弱黏结煤为主,煤层的黏结性变化规律受深成变质作用影响,变质程度由低至高,煤的黏结性也随之逐渐增强。5#煤层煤岩特征以半亮-半暗煤为主,镜质组含量较高,以较干燥森林沼泽相和湖沼相为主。绘制了煤质指标的等值线图,研究其分布特征及变化规律,并参照焦化、气化、液化用煤指标体系对5#煤清洁利用方式进行划分,结果显示,5#煤洗选后大部分可作为焦化用煤,部分煤可作为直接液化用煤。  相似文献