109 resultados para 3-20
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中国牡蛎种类丰富,但是由于贝壳可塑性强,表型变化大,分类学及系统发生学研究进展缓慢,存在诸多争议。本文在全国部分海区采集牡蛎样品,并通过表型和分子生物学方法进行鉴定,重点调查潮下带牡蛎的分布情况。选取江苏南通小庙洪牡蛎礁作为典型海域,研究亲缘关系接近的巨蛎属牡蛎之间在繁殖上如何维持相互之间的关系。本研究的目的在于摸索牡蛎物种鉴定的实用方法,并阐明熊本牡蛎和近江牡蛎生殖隔离是如何维持的。研究结果对牡蛎等海洋贝类的分类及系统发生学研究具有一定的借鉴作用,为牡蛎礁的生态保护提供生物学参考依据。 在辽宁营口、海洋岛,河北秦皇岛,山东西霞口、潍坊、青岛,江苏南通,浙江舟山、奉化,福建莆田,广东汕头等地区采集牡蛎样品,重点采集潮下带的牡蛎,通过地理分布、表型、DNA含量测定和COI种特异性探针鉴定对各地区的牡蛎物种组成进行分析。选取了南通小庙洪牡蛎礁作为研究牡蛎物种间相互关系的最佳地点。该地区牡蛎由主要分布在潮间带的熊本牡蛎和主要分布在潮下带的近江牡蛎组成。 对南通小庙洪牡蛎礁上两种巨蛎属牡蛎在空间上的分布进行调查;定期取样,制作性腺切片,观察两种牡蛎的性腺发育情况;同时,定期在海区挂板,采用半人工采苗的方式采集海区牡蛎幼体,通过ITS1基因鉴定采集的稚贝所属物种。通过调查发现二者的分布存在重叠区域;两种牡蛎在2007年6月中旬至9月中旬存在两个明显的繁殖高峰期,在每个繁殖期内两种牡蛎同时发生大量繁殖行为的可能性极高。结果表明,两种牡蛎不存在明显的生态隔离和季节隔离等交配前生殖隔离机制。 在室内对两种牡蛎进行2×2完全双列杂交,并通过ITS1基因的克隆测序验证杂种后代。双列杂交受精实验采用多亲本混合交配的方式(即每个物种的卵子或精子均来自多个个体),共进行7次重复。结果表明,熊本牡蛎的卵子能够被近江牡蛎的精子以较低的受精率(24.6%)受精,且形成的后代确实为两个物种杂交产生,而反方向不能受精。 幼虫和稚贝生长存活的双列杂交实验共进行3次重复。估测受精率、受精卵的孵化率,第1至29日每两天测量一次D形幼虫的壳高和密度。结果表明杂交幼虫(熊本牡蛎♀与近江牡蛎♂的杂交,SA)的受精率(12.5%)显著低于(P < 0.05)熊本牡蛎(75.4%)和近江牡蛎(84.5%)纯种对照组;而孵化率与对照组无显著差异(P > 0.05);自受精至29日龄,杂交幼虫壳高的生长速度明显低于纯种对照组(P < 0.05);但是存活率与熊本牡蛎无显著差异(P > 0.05)。杂交幼虫附着变态期间死亡率高;93日龄,熊本牡蛎有10.08%的匍匐期面盘幼虫存活至稚贝,显著大于(P < 0.05)近江牡蛎(2.18%)和杂交幼虫(0.76%);杂交稚贝壳高显著小于(P < 0.05)纯种对照组。稚贝在海区挂养3个月。与挂养前相比,杂交稚贝在潮下带的存活率为19.2%,125个稚贝仅存24个,壳高平均增加2.15 mm。熊本牡蛎在潮间带的存活率达到65%,壳高平均增加3.99 mm。近江牡蛎在潮下带的存活率达到85.7%,壳高平均增加5.22 mm,在潮间带的存活率仅10.9%,壳高平均增加3.28 mm。受精6个月后,所有杂交稚贝仅剩3枚,运回实验室暂养一段时间后全部死亡。 设置20、25、30、35共4个盐度梯度,估算双列杂交组合在不同盐度下的受精率、孵化率、7日内的存活率和壳高生长,实验共进行3个重复。结果表明,杂交组合在4个盐度下的受精率(平均为11.2%)均显著低于(P < 0.05)熊本牡蛎(75.0%)和近江牡蛎(77.5%)纯种对照组;而孵化率与对照组无显著差异(P > 0.05);杂交组合在盐度35时的孵化率(85.0%)显著大于20(49.6%)、25(51.3%)和30(55.4%)三个盐度梯度。7日龄杂交幼虫(10.5%)和近江牡蛎(11.4%)的存活率显著小于(P < 0.05)熊本牡蛎(30.3%);杂交幼虫的壳高(75.7 μm)显著小于(P < 0.05)熊本牡蛎(81.5 μm)和近江牡蛎(85.6 μm)对照组。两因素方差分析表明,杂交组合方式对受精率、孵化率、7日龄存活率和7日龄壳高均有显著影响,盐度对7日龄壳高的影响显著。 实验结果表明,江苏小庙洪牡蛎礁上的熊本牡蛎和近江牡蛎之间在分布空间上存在重叠区域,繁殖时间也存在重叠,并未产生明显的生态隔离和季节隔离。二者之间存在不对称性杂交,熊本牡蛎的卵子能够与近江牡蛎的精子以较低的受精率受精,而反方向完全不亲和。杂交幼虫在受精率上存在显著劣势;但是受精卵的孵化率与纯种受精卵无显著差异;杂交幼虫在生长上也存在显著劣势;而存活率与熊本牡蛎无显著差异;杂交幼虫附着变态期间大量死亡,存活下来的稚贝生长缓慢,死亡率高。表明熊本牡蛎和近江牡蛎之间即存在交配前的配子不亲和性隔离,又存在交配后隔离,主要表现为杂种不活。
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The fatty acid compositions of 22 species of marine macrophytes, belonging to the Ceramiales, Cryptonemiales, Nemalionales, Laminariales, Chordariales, Scytosiphonales, Desmarestiales, Dictyosiphonales, Fucales, Dictyotales and Ulvales and collected from the Bohai Sea, were determined by capillary gas chromatography. The contents of polyunsaturated fatty acids (FAs) in the Bohai Sea algae, in comparison with the same species from the Yellow Sea were found to be lower. Red algae had relatively high levels of the acids 16:0, 18:1(n-7), 18:1(n-9), 20:5(n-3) and 20:4(n-6), and those examined were rich in C-20 PUFAs, these chiefly being arachidonic and eicosapentaenoic acids. The major FAs encountered in the Phaeophyta were 14:0, 16:0, 18:1(n-9), 18:2(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3). C18PUFAs are of greater abundance in the brown algae than in the red algae examined. All three green algae from the Ulvales had similar fatty acid patterns with major components, 16:0, 16:4(n-3), 18:1(n-7), 18:2(n-6), 18:3(n-3), and 18:4(n-3). They contained 16:3(n-3) and more 16:4(n-3), were rich in C18PUFAs, chiefly 18:3(n-3) and 18:4(n-3) and had 18:1(n-7)/18:1 (n-9) ratios higher than 1. (C) 2002 Elsevier Science Ltd. All rights reserved.
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为了解春小麦萌发期生理生化变化对干旱胁迫的响应及为早期抗旱筛选鉴定提供科学依据,选用抗旱性不同的9个春小麦品种为材料,在20%聚乙二醇(PEG6000)干旱胁迫下和非干旱胁迫下进行萌发试验,研究了α-淀粉酶活性及其同工酶的表达。结果表明:1)在两种胁迫处理下,α-淀粉酶活性在品种间都存在着差异,但干旱胁迫下抗旱品种α-淀粉酶活性显著高于干旱敏感品种;2)α-淀粉酶活性与胚芽鞘长度之间呈显著正相关;3)在20%PEG6000胁迫下,抗旱品种α-淀粉酶同工酶受抑制较小,条带较多,胚芽鞘长度与主胚根长度受抑制较小。因此认为,抗旱品种在干旱胁迫下有着较高的萌发势,可能与具有表达α-淀粉酶同工酶的强势基因型有关;干旱胁迫下α-淀粉酶活性和α-淀粉酶同工酶可以作为春小麦抗旱性筛选和鉴定的指标。
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通过观察、套袋、人工授粉对引种至低海拔栽培地的2种“藏茵陈”类植物——川西獐牙菜(Swertia mus-sotii)和抱茎獐牙菜(S.franchetiana)繁育系统进行研究.结果表明:(1)引种的2种植物均为雌雄同株、自交亲和,但大部分花雌雄异熟(dichogamy)和雌雄异位(herkogamy),雌雄同熟的比例为24%,且雌雄同熟的雄蕊群远离雌蕊,需要靠传粉昆虫等传粉媒介传粉.(2)引种到低海拔的2种“藏茵陈”类植物结实率和发芽率均较高,其中川西獐牙菜柱头张开第2天的授粉结实率达76.54%,种子发芽率达84.29%.(3)低海拔栽培的川西獐牙菜的传粉昆虫是家养蜜蜂,抱茎獐牙菜的开花时间较川西獐牙菜晚20 d,有效的传粉昆虫由家养蜜蜂变成一种很小的蜂类.研究表明,川西獐牙菜和抱茎獐牙菜由高海拔引种到低海拔地区后,结实率和种子发芽率均较高,可以用引种栽培的方式进行“藏茵陈”药材的繁殖.
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对祁连山海北高寒草甸地区近夏至日微气象观测分析表明: (1) 14:00 (北京时,下同) 太阳总辐射瞬时值最高可达1061 W·m-2 , 净辐射、反射辐射、光合有效辐射和紫外辐射分别为670、218、380 和168 W·m-2 , 分别约为太阳总辐射的58 %、20 %、36 %和14 % , 6 月下旬日平均反射率约为0. 22 ; (2) 土壤热通量、感热通量和潜热通量瞬时值最大分别为91、274 和362 W·m-2 , 相应占净辐射的比例为20 %、38 %和42 %; (3) 地—气温度在一定范围的水平和垂直方向变化较为剧烈, 大气逆温约出现于20 :00 至次日11 :00 , 午夜01 :00 最强; (4)风速阵性强, 有显著日变化的时间性分布。
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研究了大吴风草属的核形态。染色体间期为复杂型;前期染色体为中间型。染色体长度从3. 70μm 到2. 64μm, 平均长度为3. 20μm;核型公式为2n= 60= 14m + 26sm + 20st (4SA T), 为3A类型。过去认为大吴风草属与橐吾属接近, 并比之原始;但染色体和花粉特征并不支持这种处理。
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研究青藏高原金露梅灌丛和矮嵩草草甸两种植被类型枯枝落叶分解作用强度及其随着埋放时间延长的变化规律。结果表明, 两种植被的枯枝落叶在埋放的前3 个月均显示出明显的分解效果。其总分解率分别达到20. 31%和30. 4% , 随后分解率逐渐降低, 埋放后5 个月的总分解率仅为前3 个月的37. 60% 和39. 33%。矮嵩草草甸枯枝落叶的分解率显著高于金露梅灌丛。土壤温度、微生物数量和枯枝落叶本身的化学成分是影响分解率的主要因素。与其相比, 动物粪便的分解率很低。
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Located in the Paleozoic uplift along the southern margin of Tu-Ha basin in eastern Xinjiang, the newly discovered Hongshan Cu-Au deposit occurs in the superimposed Mesozoic volcanic basin upon the north section of later Paleozoic Dananhu-Tousuquan accretionary arc. Kalatage Cu-Au orebelt is controlled by NWW-trend faults, and includes Hongshan and Meiling Cu-Au deposits. The host rocks of Hongshan ore district are mainly rhyolitic-dacitic ignimbrites, whereas Cu-Au mineralization is closely related to quartz porphyry, rhyolitic porphyry and granitic porphyry. Mineralization styles are dominantly veinlet-disseminated and veinlet, occasionally stockwork. The mineral association is chalcopyrite, pyrite, bornite, chalcocite and sphalerite. The hydrothermal alteration consists of silicfication, sericitization, alunitization, pyrophylitization, illitization, hydromuscovitization, and chloritization. Hongshan Cu-Au deposit, on the edge of the desert, is one of the driest areas in eastrn Tianshan. Moreover, the highest temperature has been up to 60℃, and the average rainfall receives only 34.1mm/y. The light rainfall and rapid evaporation in the vicinity of this deposit have allowed the formation of a great variety of water-soluble sulfates. Oxidization zone of this deposit lies on the upper part of primary sulfide orebodies appearing with a depth of 50-60m, which is dominant in sulfate minerals. 1. Based on the field observation, the volcanic and sub-volcanic rock composition, hydrothermal alteration, ore structure and mineralization characteristics, this paper proposed that the Hongshan Cu-Au deposit belongs to a transitional type from high-sulfide epithermal to porphyry Cu-Au deposit, which corresponds with the typical HS-epithermal deposit such as Zijinshan Au-Cu deposit in Fujian Province, SE-China. 2. The Hongshan copper-gold deposit was controlled by the tectonic, stratum, magma activity and volcanic apparatus, whereas Au mineralization is closely related to quartz porphyry, rhyolitic porphyry and fine grained pyritization in hydrothermal activity, and Cu mineralization is closely related to quartz porphyry and hydrothermal explosive breccia. 3. Oxidation zone of Hongshan Cu-Au deposit lies on the upper part of primary sulfide orebodies deposit. 23 sulfate minerals were identified in this work. The results of samples XRD and chemical analysis were furthermore confirmed through thermal, infrared spectrum and mössbauer spectrum analysis. Among those, nine minerals as Ferricopiapite, Cuprocopiapite, Rhomboclase, Parabutlerite, Krausite, Yavapaiite, Metasideronatrite Kroehnkite and Paracoquimbite were founded in China for the first time. And Paracoquimbite was secondly reported in the world (first case reported at 1938 in Chile). 4. EPMA analysis shows that Al impurity in crystal lattice is important to polytype formation of paracoquimbite and coquimbite besides stack fault. 5. Compared with Meiling Cu-Au deposit in the same Kalatage ore belt from the characteristics of δ34S of barite, lithofacies, hydrothermal alteration and homogeneous temperature, Hongshan Cu-Au deposit belongs to the same metallogenic system of HS-epithermal type as Meiling Cu-Au deposit. But Hongshan Cu-Au deposit has less extensive alteration and shallower denudation. 6. Sulfur isotope analyses show that δ34S values of pyrites vary in the range of +1.86‰~+5.69‰, with an average of 3.70‰, mostly in the range of +1.86‰~+3.20‰, and δ34Scp<δ34Spy. Therefore ore-forming fluid of porphyry comes from mantle and was contaminated by the earth’s crust. Sulfur isotope has reached balance in ore-forming process. 7. Sulfur isotope analyses show that δ34S values of sulfates vary in the range of +2.15‰~+6.73‰, with an average of +3.74‰, mostly equals as δ34S values of primary sulfides in Hongshan Cu-Au deposit. So supergene sulfates inherit sulfur of primary sulfide. δ34S values are mostly same in different sulfates. As well as pyrite and chalcopyrite, volcanic hot spring and associated native sulfur underground also provide water medium and sulfur during the formation process of sulfate. 8. According to the EPMA of sample chalcopyrite and pyrite in Hongshan Cu-Au, the value of Cu/Ni is 0.98-34.72, mostly close to the value of 5, which shows that Hongshan deposit is a typical volcanogenic magmaic hypothermal deposit. Au and Ag, Zn, Te and Bi are positive correlation, Cu and Hg, Se, Sb are positive correlation, indicates Au and Cu don’t locate in the factor of mineralization of same mineralization groups. The reasons of gold concentration in the oxidation zone are: 1). Change of redox potential (Eh) makes gold to deposit from the liquid of mineralization zone; 2). PH is one of the most factors of gold’s deposition; 3). Soluble complex and colloid of gold can be adsorbed easily. 9. The biotite and hornblende K-Ar isotopic ages from the wall rock-quartz diorite, biotite granite and monzonite granite are 231.99±3.45Ma, 237.97±2.36Ma and 296.53±6.69Ma respectively. The ore-bearing rhyolitic breccia lava contains breccia of the biotite granite which indicates the volcanism and related Cu-Au mineralization occurred later than the granite, possibly in Mesozoic. K-Ar ages of granitoids in Sanya, Baishiquan and Hongliugou area and Molybdenite Re-Os age of Baishan Mo deposit all are in Triassic. Besides late Paleozoic magmatism, igneous magmatic event of Mesozoic was widespread in eastern Tianshan. 10. The K-Ar age dating indicates that the K-Ar age of Voltaite occurred below surface 1m is 56.02±3.98Ma, K-Ar age of Ferricopiapite occurred below surface 1.5m is 8.62±1.12Ma, K-Ar age of Yavapaiite occurred below surface 14 m is 4.07±0.39Ma, and K-Ar age of Voltaite occurred below surface 10 m is 14.73±1.73Ma. So the age interval of oxidation zone of Hongshan copper-golden bed is between 60 -3.38Ma. Oxidization occurred at Caenozoic era (from 65Ma), which can be identified through comparing with different deposits oxidation zone in other countries. The coupling between global tectonic event and climatic change event which occur from Caenozoic era has some effect on epigeosphere system, which can act on the surface of bed oxidation zone similarly. It induces that the age mentioned above coincide with collision of India-Asia and multistage uplifting of Qinhai-Tibet Plateau happened subsequently. Bed oxidation zone is the effect and record of collision and uplifting of Tibet Plateau. The strong chemical weathering of surface accumulation to which was leaded by PETM event occurred Paleocene and Eocene is the reason of Voltaite sharply rises. On the contrary, Ferricopiapite formed due to the global cold weather. The predecessor did much research through biota, isotopes, susceptibility, but this paper try to use different sulfate mineral instead of climatic change. So the research of sulfate minerals not only indicates a great deal of oxidized zone feature, but also the intergrowth of sulfate minerals may be used to trace paleoenviroment and paleoclimate of oxidation zone. 11. Analysis of the information of alteration and mineralization features of four bore cores, induced activity polarization well logging and Eh-4 geophysical section, deep mineralization anomaly objects of Hongshan ore districts shows low resistance, middle and high polarization, measurements of Eh-4 consecutive conductance section show the existing of concealed porphyry ore body deeper than 450m, on the top of and around rock body there are low resistance body ranged from 100-300Ω•m, this area may be the ore-bearing part. In a word, Hongshan Cu-Au deposit deposit is a combine of upper HS-style epithermal Au deposit and deeper porphyry mineralization system. It has great potential to find large HS-style epithermal-porphyry Au-Cu deposits. This paper consists of seven chapters and twenty seven sections. The geological character of deposit is basic condition in this work. Constitute of oxidation zone, research of sulfate mineral, relation between oxidation and primary zone, K-Ar ages of potassic sulfate are key parts of thesis. Genesis of ore deposit is the further expansion of this research. Analysis of ore-controlling factors is the penetration above basic. Analysis of potential is application of exploration.
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The Study on rheology of the lithosphere and the environments of the seismogenic layer is currently the basic project of the international earthquake research. Yunnan is the ideal place for studying this project. Through the multi-disciplinary comprehensive study of petrology, geophysics, seismo-geology, rock mechanics, etc., the depth-strength profiles of the lithosphere have been firstly constructed, and the seismogenic layer and its geophysical and tectonic environments in Yunnan have been systematically expounded in this paper. The related results achieved are of the important significances for further understanding the mechanism of strong earthquake generation, dividing the potential foci and exposing recent geodynamical processes in Yunnan. Through the comprehensive contrast of the metamorphic rocks in early and middle Proterozoic outcropping on the surface, DSS data and experimental data of rock seismic velocity under high temperature and high pressure, the petrological structure of the crust and upper mantle has been studied on Yunnan: the upper, middle and lower crust is composed of the metamorphic rocks of greenschist, amphibolite and granulite facies, respectively or granitoids, diorites and gabbros, respectively, and the upper mantle composed of the peridotites. Through the contrast studies of the heat flow and epicenters of the strong earthquakes, the distribution of the geotemperature and the data of focal depth, the relationship of between seismicity and geothermal structure of the lithosphere in Yunnan has been studied: the strong earthquakes with magnitude M ≥ 6.0 mainly take place at the geothermal gradient zone, and the seismic foci densely distribute between 200~500 ℃ isogeotherms. On the basis of studies of the rock properties and constituents of the crust and upper mantle and geothermal structure of the lithosphere, the structure of the rheological stratification of the lithosphere has been studied, and the corresponding depth-strength profiles have been constructed in Yunnan. The lithosphere in majority region of Yunnan has the structure of the rheological stratification, i.e. the brittle regime in the upper crust or upper part of the upper crust, ductile regime in the middle crust or lower part of the upper crust to middle crust, ductile regime in the lower crust and ductile regime in the subcrustal lithosphere. The rheological stratification has the quite marked lateral variations in the various tectonic units. The distributions of the seismogenic layer have been determined by using the high accurate data of focal depth. Through the contrast of the petrological structure, the structure of seismic velocity, electric structure, geotemperature structure, and rheological structure and the study of the focal mechanism in the seismogenic layer, the geophysical environments of the seismogenic layer in Yunnan have been studied. The seismogenic layer in Yunnan is located at the depths of 3 ~ 20 km; the rocks in the seismogenic layer are composed of the metamorphic rocks of greenschist to amphibolite facies (or granites to diorites); the seismogenic layer and its internal focal regions of strong earthquakes have the structure of medium properties with the relatively high seismic velocity, high density and high resistivity; there exists the intracrustal low seismic velocity and high conductivity layer bellow the seismogenic layer, the geotemperature is generally 100~500 ℃ in the depth range in which the seismogenic layer is located. The horizontal stress field predominates in the seismogenic layer, the seismogenic layer corresponds to the brittle regime of the upper crust or brittle regime of the upper crust to semibrittle regime of the middle crust. The formation of the seismogenic layer, preparedness and occurrence of the strong earthquakes is the result of the comprehensive actions of the source fault, rock constituent, structure of the medium properties, distribution of the geotemperature, rheological structure of the seismogenic layer and its external environments. Through the study of the structure, active nature, slip rate, segmentation of the active faults, and seismogenic faults, the tectonic environments of the seismogenic layer in Yunnan have been studied. The source faults of the seismogenic layer in Yunnan are mainly A-type ones and embody mainly the strike slip faults with high dip angle. the source faults are the right-lateral strike slip ones with NW-NNW trend and left-lateral strike slip ones with NE-NEE trend in Southwestern Yunnan, the right-lateral strike slip ones with NNW trend and left-lateral strike slip ones with NNE trend (partially normal ones) in Northwestern Yunnan, the right-lateral strike slip ones with NWW trend in Central Yunnan and left-lateral strike slip ones with NW-NNW trend in Eastern Yunnan. Taking Lijiang earthquake with Ms = 7.0 for example. The generating environments of the strong earthquake and seismogenic mechanical mechanism have been studied: the source region of the strong earthquake has the media structure with the relatively high seismic velocity and high resistivity, there exists the intracrustal low velocity and high conductivity layer bellow it and the strong earthquakes occur near the transitional zone of the crustal brittle to ductile deformation. These characteristics are the generality of the generating environments of strong earthquakes. However, the specific seismogenic tectonic environments and action of the stress field of the seismic source in the various regions, correspondingly constrains the dislocation and rupture mechanical mechanism of source fault of strong earthquake.
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云南大红山层状铜矿是大红山铁铜矿床的一部分。其成矿主要分为两个阶段:早期火山喷流作用形成了层状铜矿矿胚。而后期热液对原先的矿胚进行了改造和富集。本文选取大红山层状铜矿中石英脉型铜矿石石英样品系统地进行了流体包裹体的研究,主要发现了富液相(L+V)、舍子晶多相(L+S±V)和纯CO2三类主要包裹体。显微测温结果表明,其均一温度在103-456℃之间;盐度范围为0.53%~59.76%NaCl equiv.,密度为0.80~1.45g/cm^3;纯CO2包裹体均一温度为-34.3-20.8℃,对应密度为0.77-1.09g/cm^3。稳定同位素测定结果表明,硫化物δ^34S分布范围为-0.6‰~+10.9‰,表明岩浆硫和海水硫酸盐还原成因硫参与了早期成矿过程。方解石δ^13 CPDB值范围为-5.6‰~-3.1‰,与地幔碳同位素值(-5.0±2‰)完全吻合,暗示了热液中碳质有地幔来源。根据氧同位素方解石-水及石英-水之间的分馏方程,计算得到成矿流体中水的δ^18 OSMOW值在-1.9‰-13.7‰之间,与火成岩δ^18O范围(5‰~15‰)基本一致。根据矿体地质特征、岩相学、流体包裹体以及稳定同位素等方面的综合研究,本文认为在喷流沉积之后的挤压环境下,从地幔分异出来的高温、中-高盐度并富含CO2的流体和海水一起改造了原岩,形成了变质火山-沉积岩,并使原先的铜矿矿胚活化富集.
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在前人对热带亚热带季风型气候条件下云南个旧砂矿、老挝Xaymomboun特区Ban Nameung铜多金属矿和Champasak省Boloven高原玄武岩等研究成果基础上,采用典型表生矿床实证解剖思路,选择个旧白云岩风化剖面、锡铅砂矿、锰结核、砂矿重选流程、Ban Nameung硫化氧化矿和Boloven玄武岩风化壳等对象,通过岩矿鉴定、主量微量元素地球化学、稀土元素地球化学、人工重砂、化学物相和微区分析等研究手段,研究这些矿床表生成矿物质来源、成矿机理、矿床地球化学特征和矿物工业可利用性等内容,并探索热带亚热带季风型气候条件下典型矿床表生成矿三个问题:(1)Sn、Pb、Mn、Ag、REE、Nb、Ta、Ga和Cd等元素表生富集成矿(矿化)规律;(2)上述元素成矿机理和工业利用可能性;(3)典型矿床其他20几种元素表生贫化与富集规律。研究获得如下主要认识: 1. 个旧地区燕山期以来持续抬升和亚热带季雨林的表生环境,使个旧地区大面积出露的碳酸盐岩风化形成强烈岩溶地貌,碳酸盐岩风化过程中CaO和MgO大量淋失,为砂矿提供了巨大容矿空间,同时碳酸盐地区碱性环境有利于原生硫化矿分解。含矿或不含矿白云岩、花岗岩、玄武岩、夕卡岩和原生硫化矿石等风化形成粘土矿物和铁锰氧化物,释放出Sn、Pb、Mn、Ga、Cd、Ag、In、Cu和Zn等元素,难风化重矿物如锡石表生残留富集,而粘土矿物和铁锰氧化物对成矿元素吸附是砂矿表生成因机理之一。 2. 个旧地区岩溶型砂矿形成机理为:(1)原生重矿物残留富集成矿,如锡石、磁铁矿。(2)金属硫化物残留成矿,如砂矿中残存大量方铅矿、黄铜矿、黄铁矿,是原生硫化物残留结果。(3)表生矿物富集成矿,如白铅矿、孔雀石、自然铅和自然铜等富集。(4)铁锰氧化物吸附和包裹成矿,如铁锰氧化物吸附Pb和Ga等元素,包裹含Pb和Zn微粒矿物。(5)锰结核吸附包裹成矿,锰结核吸附和包裹Sn、Pb和Cu等元素和微粒矿物。(6)类质同象成矿,如Ga和Al类质同象,Cd和Zn等类质同象成矿。(7)岩溶作用成矿,岩溶落水洞或溶洞内水流冲刷使锡石等重矿物富集成矿。元素表生成矿不仅是单一成矿作用结果,而是综合作用结果,如Pb有表生矿物富集成矿,也有铁锰氧化物吸附成矿。 3. 砂矿中锰结核是锰铁结核,主要成分为Fe2O3 、Al2O3、SiO2和MnO等,包裹了赤铁矿、方解石、云母、石英、蒙脱石、高岭石、白云石、钾长石等和锡石、白铅矿等矿物。锰结核中Mn、Sn、Pb、Ag、Ga、Cd和In富集成矿,Cu和Zn富集矿化,锰结核比砂矿更富集Mn、Pb和REE,其成矿机理应是吸附和包裹成矿元素或矿物使其富集成矿。 4. 个旧表生砂矿共生伴生组分复杂,有用矿物有锡石、方铅矿、白铅矿、黄铜矿、自然铅、自然铜、孔雀石、软锰矿、白钨矿、磁铁矿和褐铁矿等。模拟岩溶作用自然过程中砂矿矿物流向的源兴采选车间砂矿重选流程结果表明,锡铅精矿中Pb、Ga、Mo、Cd、In、Cu和Zn等金属总实收率仅为3.03%~6.44%,绝大部分金属留在了尾矿中。一段床和矿泥床分析中,Ag和Mn回收率低于0.66%~0.29%,Ag富集在硫化物态中,没有富集在铁锰氧化物态中;Mn富集在碳酸盐态中,没有铁锰氧化物态中。整个流程中Pb、Mn、Cu和Zn等富集在碳酸盐态矿物中,没有富集在硫化物态中。选矿流程没有利用具有潜在利用价值矿物如磁铁矿。重选流程解释了岩溶过程能富集Pb、Mn、Cu和Zn的碳酸盐矿物,不能富集这些元素的硫化矿物。 5. 老挝Ban Nameung硫化矿氧化初期,风化产物中Ag、Pb、Zn和Cu淋失,SiO2、K2O和CaO富集,风化后期Ag、Fe和Mn富集。硫化矿风化过程中,Au硫化物态部分变为有机态和铁锰氧化物态;Ag硫化物态部分变为铁锰氧化物态和有机态;Cu硫化物态部分变为铁锰氧化物态和碳酸盐态;Pb硫化物态、吸附态、碳酸盐态和铁锰氧化物态部分变为铁锰氧化物态、碳酸盐态和有机态;Zn硫化物态变为部分铁锰氧化物态、有机态、碳酸盐态和吸附态矿物。随着风化作用加强,上述几种相态比例还会改变。 6. 老挝Boloven新生代亚碱性玄武岩富Nb、Ta和Ga等微量元素,风化壳中REE、Nb、Ta和Ga已富集成矿,∑REE最高775×10-6~1003×10-6,(Nb2O5+Ta2O5)最高642×10-6~656×10-6,Ga最高81.6 ×10-6。风化壳中达到边界品位的(Nb2O5+Ta2O5)厚度有2m以上。REE可能存在于含P和Ti矿物中,也可能形成REE独立矿物。Nb、Ta和Ga应赋存在Ti、U、Zr和Th矿物中,其成矿应是重矿物表生残留富集结果,与粘土矿物吸附和三水铝石关系不紧密。