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1.
对准噶尔南缘郝家沟剖面下侏罗统三工河组的沉积相与层序地层特征进行了详细的研究,确认三工河组发育辫状河三角洲沉积。辫状河三角洲包括辫状河三角洲平原亚相、辫状河三角洲前缘亚相和前辫状河三角洲亚相。辫状河三角洲前缘亚相又可进一步划分为水下分流河道、水下分流河道间、席状砂和河口坝等微相类型。三工河组辫状河三角洲沉积除一些层位的辫状河道沉积物颗粒较粗外,主体沉积物以砂岩、粉砂岩和泥岩为主,为砂质辫状河三角洲。运用高分辨率层序地层学基准面旋回划分原理,将三工河组划分为2个中期基准面旋回,下部中期基准面旋回又可划分为4个短期基准面旋回,上部中期基准面旋回发育不完整。  相似文献   

2.
The pre‐Devonian sedimentary and volcanic sequence exposed along the south coast of New South Wales has previously been divided into three stratigraphic groups: (1) Upper Ordovician graptolite‐bearing slate which is conformable with (2) interlayered thinly‐bedded greywacke and pelite of undifferentiated Ordovician age and (3) Cambrian successions of interlayered chert, pelite and volcanic rock at Bate‐mans Bay and Narooma. The main bases for this subdivision are a change in rock types between (1) and (2), and the unconformity between (2) and (3) formerly proposed on the basis of changes in rock type and fold style across the boundary. New structural data are presented which refute the presence of the unconformity, and conformity of (2) and (3) with the fossiliferous slates is established.  相似文献   

3.
周景尧  李哲  陈家玮 《地学前缘》2019,26(4):295-300
基于硫酸根自由基的高级氧化技术能有效降解水中磺胺类药物残留。由于在自然环境中共存重金属会对环境修复效果产生一定影响,文中重点研究了不同pH环境条件下不同重金属离子对针铁矿活化过硫酸盐(PS)去除水中磺胺吡啶(SPY)的影响。不同类型重金属离子(Cu^2+、Pb^2+、Cd^2+,0.2mmol/L)在反应体系(初始条件:针铁矿,1.0g/L;PS,4mmol/L;SPY,10mg/L;pH=8.2)中对SPY的降解对比研究发现:在无重金属共存的条件下,针铁矿/PS体系降解SPY的去除率为25.2%;Pb^2+和Cd^2+对针铁矿/PS体系的影响较弱,去除率分别为30.8%和34.8%;Cu^2+的促进作用很大,可以使SPY被完全降解(100%)。机理分析认为,在针铁矿/PS体系中Pb^2+和Cd^2+主要通过影响吸附作用导致磺胺吡啶被去除,而Cu^2+主要通过自身活化PS的作用。不同pH条件(3.0,8.0,12.0)实验证实弱碱性条件下,Cu^2+/针铁矿/PS能够发挥较高的活性从而降解SPY。本文结果为采用针铁矿活化过硫酸盐技术修复类似复合污染地下水环境提供了实验依据。  相似文献   

4.
New data on the composition of tagamites (impact melt rocks) of the Popigai atsrobleme (Siberia) are presented. The preliminary results support the following major conclusions: (1) the matrix of the studied tagamites is crystallized and is composed of identified minerals; (2) the degree of the matrix crystallization and the amount of inclusions in tagamites can vary significantly; (3) tagamites are identical to the intracrater gneisses of the Popigai astrobleme by the REE contents and are distinct from them by significantly lower SiO2 and higher Al2O3, FeO, MgO, and CaO contents; (4) the Popigai tagamites and intracrater gneisses are enriched in Ni (on average) in comparison with gneisses of the Khapchan Group; and (5) the various (often sufficient) degrees of crystallization of tagamites indicate the duration of the cooling of the melt, when diamonds could possibly have been dissolved.  相似文献   

5.
额尔古纳地块基底岩石时代与构造属性一直颇受争议。笔者对额尔古纳地块南部比列亚铅锌多金属矿区ZK6301钻孔226 m片麻状二长花岗岩岩心进行了锆石LA-ICP-MS定年。测试结果显示,24个测试点的数据均在谐和线上,207Pb/206Pb年龄包括4个不同年龄区段,分别为:2 549~2 562 Ma(加权平均年龄为(2 555±19) Ma,MSWD=0.17,n=3),2 596~2 624 Ma(加权平均年龄为(2 606±17) Ma,MSWD=0.032,n=17),2 688~2 715 Ma(加权平均年龄为(2 702±18) Ma, MSWD=0.70,n=3),2 786 Ma(n=1)。通过锆石的Th,U质量分数与Th/U值分析,207Pb/206Pb年龄((2 606±17) Ma)代表了该片麻状二长花岗岩的结晶年龄;207Pb/206Pb年龄((2 549~2 562) Ma)很可能代表了构造热事件的作用年龄;本次报道的岩石结晶年龄,揭示了额尔古纳地块上存在新太古代的结晶基底。结合前人研究资料分析可知,额尔古纳地块上该期变质结晶基底可能在该地块的南、北部均有分布,并且得尔布干断裂可能并非该地块的南部边界。综合分析前寒武纪古老地块的演化历史可得出,额尔古纳地块经历了全球大陆构造旋回演化的完整过程。  相似文献   

6.
The possibility to use some widely known standard discrimination diagrams such as the K2O/Na2O-SiO2/Al2O3, SiO2-K2O/Na2O, (Fe2O3* + MgO)-TiO2, F1-F2, Th-La-Sc, Sc-Th-Zr/10, and Sc/Cr-La/Y for deciphering the paleogeodynamic settings of sedimentary sequences is considered with reference to the Lower and Middle Riphean (Mesoproterozoic) deposits of the Uchur-Maya region (Far East) and the Bashkir meganticlinorium (South Urals). It was shown that only some of them can be used with a certain degree of confidence for reconstructing the settings of the platform sedimentary sequences made up of both sandstones and fine-grained terrigenous rocks.  相似文献   

7.
Petrology of the Upper Border Series of the Skaergaard Intrusion   总被引：3，自引：3，他引：3  
The Upper Border Series of the Skaergaard intrusion consistsof a 960 m thick sequence of rocks that crystallized againstthe roof of the magma chamber. The texture and composition ofthe unit vary systematically from top to bottom as a resultof changes that occurred in the magma during the solidificationof the intrusion. The order of crystallization of primocrystminerals in the Upper Border Series was: olivine; + plagioclase;+ apatite; + ilmenite; + magnetite; + Ca-rich pyroxene;—olivine;+ olivine; + ferrobustamite. The major silicate phases varyfrom high-temperature compositions to low-temperature compositionswith increasing distance from the upper contact. Post-crystallizationre-equilibration has affected the compositions of the oxideminerals and to a lesser extent the compositions of olivineand Ca-rich pyroxene. The Upper Border Series differentiationsequence differs from the Layered Series sequence, in that:(1) apatite appears much earlier; (2) magnetite precipitatedbefore Ca-rich pyroxene rather than after it; (3) orthopyroxeneis much less common; (4) the plagioclase is systematically poorerin K2O; and (5) the rocks are systematically richer in K2O andSiO2. The upper part of the Skaergaard magma appears to havebeen enriched in H2O, K2O, SiO2, and P2O5 relative to the partthat was parental to the Layered Series.  相似文献   

8.
西准噶尔地区中-上志留统玛依拉山组主要分布于玛依拉山一带,以玛依勒蛇绿岩的围岩产出,两者为断层接触,主要组成为灰绿-暗灰绿色凝灰质粉-细砂岩,砂岩和砂砾岩组合,夹硅质岩和玄武岩。对玄武岩进行详细的岩石地球化学研究表明,SiO2含量中等(47.1%～53.92%),高Fe2O3T(12.54%～17.82%)、Al2O3(13.3%～15.7%)、Na2O(3.84%～8.02%),低TiO2(0.45%～1.48%)、MgO(3.28%～5.77%,Mg#=27.01～41.96)、K2O(0.36%～0.7%),全碱K2O+Na2O含量为4.4%～8.39%,属于亚碱性拉斑玄武岩系列。稀土元素总量较低(∑REE=27.16×10-6～54.41×10-6),轻、重稀土分馏较为明显((La/Yb)N=1.53～2.74),无明显Eu异常(Eu/Eu*=0.96～1.16),稀土配分模式类似于E-MORB。相对富集LILE(如Rb、Ba、Th和K),亏损HFSE(如Zr、Ti),明显的Nb和Ta负异常,具有岛弧玄武岩的地球化学特征。综合研究认为玛依拉山组玄武岩形成于俯冲带上的弧后盆地环境,与玛依拉山蛇绿岩的形成环境不同,其岩浆来源于尖晶石二辉橄榄岩2%～10%的部分熔融,并有少量俯冲流体的参与。结合前人研究资料,认为西准噶尔在志留纪-石炭纪处在洋内弧演化阶段。  相似文献   

9.
为掌握不同蓄水阶段温室气体通量强度,揭示水生生态系统在水库蓄水后的重建过程,选择2004年(蓄水后第1年)、2008年(蓄水后第5年)为典型年,结合同期主要环境参量,比较研究了三峡典型支流澎溪河回水区水柱表层CO2分压p(CO2)及其扩散通量FCO2特征。研究发现,2004年澎溪河双江大桥处水柱表层p(CO2)、FCO2年均值分别为(101.9±7.5)Pa、(13.99±1.58)mmol/(m2·d),2008年相应为(129.1±16.4)Pa、(19.92±3.55)mmol/(m2·d)。水位上升淹没土地带来更多有机质降解,可能引起了p(CO2)和FCO2的总体升高;蓄水过程水域生态系统逐渐完善,浮游植物生长对p(CO2)和FCO2的影响逐渐显现。  相似文献   

10.
分布于西藏林周县扎雪地区的林子宗群帕那组火山岩,主要由流纹质-粗安质熔岩和火山碎屑岩组成。岩石总体上反映出高Al高K的特点,Al2O3的质量分数平均为14.55%,K2O+Na2O的质量分数平均为8.78%,K2O质量分数平均为.77%,K2O/Na2O比值平均为2.07,显示了高钾钙碱性-钾玄质火山岩的特征。稀土配分曲线呈轻稀土富集的右倾形式,并具有中等-强烈的负Eu异常。微量元素Rb、Th强烈富集,Ta、Ba、U相对富集,而Y、Yb、Sr等相对亏损。岩石地球化学特征显示了陆壳重熔的特点。研究表明,扎雪地区帕那组火山岩是40 Ma左右陆壳加厚并部分熔融形成的,是印度板块和欧亚板块后碰撞作用的产物。  相似文献   

11.
通过对青藏高原腹地钻孔岩心剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区苟弄措湖泊沉积记录(孔深7.25 m)约30 ka BP以来的古气候变化,并在孔深3.32～1.98 m处识别出“仙女本期”的3个气候颤动事件,即:①老仙女术事件(孔深3.32～2.62 m);②中仙女本事件(孔深2.62～2.43 m);③新仙女本事件(孔深2.43～1.98 m)。这3个气候颤动事件都是以冷干时段开始、以冷湿时段结束的,并有越向后期其冷干的时段越长的变化趋势,而其后的冷湿时段却具有等时的变化趋势。岩心沉积物的有机碳、有机氮和磁化率以及化学元素含量的变化,都与仙女本期气候变化具有十分吻合的变化态势。仙女术期气候在湖泊沉积物中的响应,在青藏高原环境演化中还是首次发现,为研究第四纪末次冰期冰消期以来的气候变化提供了新的信息。  相似文献   

12.
准噶尔盆地第三纪磁性地层柱的建立   总被引：2，自引：2，他引：2  
通过对新疆准噶尔盆地第三系３个剖面古地磁样品的分析、测试，在生物地层学研究的基础上，建立了一条较为完整的第三纪磁性地层柱，标定了各组地质年代，为在不同盆地进行对比，提供了新的依据。  相似文献   

13.
为研究无机水化学离子在降雨径流示踪中的可能性,在实验流域实测降雨、地面径流、壤中流、地下水径流过程和流域内17个测孔的地下水过程中,施测了Na+,K+,Ca2+,Mg2+,Cl-,SO42-,HCO3-+CO32-,NO3-,F-,NH4-,PO42-,SiO2和pH,EC,18O的同步过程,还施测了少数土壤水水样。结果是:①在Ca2+与Cl-/SO42-和EC与Na+/(Na++Ca2+)的关系中以及除NO3-,NH4-,PO42-外的所有离子,都可识别出上述各种径流组分;②径流离子过程均与降雨离子过程相仿,随径流组分从地面到地下而渐趋坦化;③除个例外,离子浓度过程均以降雨为最小并从地面径流到地下水径流渐次增大;④降雨和地下水离子过程表现为径流离子过程的两端元;⑤在降雨和各径流组分中,18O过程与大部分离子过程有一定的同步性。从以上结果认为,降雨并不是流域径流离子输出的主要来源,然而却是形成它的主要控制因素。此外,有关试验结果还对应用Cl-进行地下水补给的估算方法提出了问题。  相似文献   

14.
青藏高原东北缘茶卡北山地区首次发现锂辉石伟晶岩脉群。这些伟晶岩脉沿宗务隆山南缘断裂北侧密集出露,并呈狭窄带状北西向展布。到目前为止,已发现9条含绿柱石锂辉石伟晶岩脉(Li2O平均品位为1.11%~3.13%,BeO平均品位为0.06%)和13条含绿柱石伟晶岩(BeO平均品位为0.044%~0.056%)。伟晶岩锆石U-Pb测年确定其成岩成矿年龄为217 Ma,含绿柱石伟晶岩具有高SiO2(71.62%~77.34%)、Al2O3(15.57%~17.55%)和富K2O(1.99%~2.02%)、Na2O(6.09%~6.24%),稀土元素总量非常低(ΣREE=5.2~9.1μg/g),轻稀土元素略微富集((La/Yb)N=6.8~10.1),Eu具负异常(δEu=0.25~0.92),具有Cs、Rb、Ta、P和Pb富集,以及Ba、Th、La、Ce、Sr、Nd和Ti的强烈亏损特征。含绿柱石锂辉石伟晶岩具有高SiO2(75.73%~77.34%)、Al2O3(15.58%~17.52%)和富Na2O(3.0%~3.16%)、贫K2O(0.36%~0.79%),稀土元素总量也很低(ΣREE=5.3~6.0μg/g),轻稀土元素略微富集((La/Yb)N=3.1~4.6),Eu具强烈负异常(δEu=0.17~0.23)。相对于含绿柱石伟晶岩,含绿柱石锂辉石伟晶岩更加富集Cs、U、Nb、Ta、Th、Sn和B,更亏损K和P。含绿柱石伟晶岩和含绿柱石锂辉石伟晶岩锆石具有相似的Hf同位素组成,εHf(t)值分布范围在–15.1~–12.9之间,对应的Hf同位素地壳模式年龄tDM2为1.99~2.22 Ga,表明伟晶岩源于全吉地块古元古代地壳物质的重熔再造。茶卡北山(含绿柱石)含绿柱石锂辉石伟晶岩的发现可推断宗务隆山构造带东段是青藏高原北部一条新的、重要的锂铍成矿带,除Li和Be外,Nb、Ta、Cs和Sn可能也是有潜力的成矿元素。  相似文献   

15.
Scheelite-bearing calc-silicate gneisses (CSG) oceur in the Montagne Noire within a series of dominant micaschists. Detailed petrographical and mineralogical studies reveal three successive stages of metamorphism and hydrothermal alteration: (1) stage 1, a regional metamorphism at 550°C and 4.5 kb where no mineralization is formed; (2) stage 2a, a hydrothermal alteration at 500 to 450°C and 4 to 3 kb which is characterized by an intense sericitization of feldpars and deposition of Sn in Sn-bearing cale-silicates; and (3) stage 2b, a hydrothermal alteration characterized by the crystallization of idocrasegrossular in CSG with concomittant precipitation of scheelite. Tungsten was transported through the micaschist environment and deposited as scheelite only in the CSG of stage 2b at relatively low pressures. To characterize the mechanism of tungsten transport, tungsten speciation at high P-T and scheelite solubility in aqueous solations buffered by the CSG and by the micaschists assemblages were calculated. It was found that H2WO 0 4 , HWO - 4 and WO 2- 4 are the dominant tungsten aqueous species in H2O–NaCl (one molal) solutions at 500°C and 2–4 kb. Calculations also indicate that scheelite deposition is controlled by decreasing pressure and increasing activity of aqueous calcium in this system. This is consistent with the petrographical and mineralogical observations. The consequences of the presence of volatiles (N2, CH4, CO2) in the regional fluids were examined by determining the effect of N2 on tungsten speciation and scheelite solubility. The addition of N2 (up to 10 mol%) to the mineralizing fluids results in a marked increase in H2WO 0 4 and HWO - 4 concentrations relative to WO 2- 4 and in a large decrease of scheelite solubility. This mechanism favours scheelite precipitation and accounts for the commonly observed association of W (and Sn) deposits with graphitic series generating mixed volatiles fluids.  相似文献   

16.
深圳沿海表层海水与地表水关系的地球化学分析   总被引：2，自引：2，他引：0       下载免费PDF全文
依据深圳沿海所取31件表层海水样品的水化学数据,对主要离子Ca2+、Mg2+、Na+、K+、SO42-和HCO3-与C l-以及B r-与C l-的关系作散点图分析。西海岸表层海水Ca2+、K+、SO42-和HCO3-与C l-的比偏离海水稀释线,源于其位于珠江河道影响范围,与珠江水有不同程度的混合;东海岸表层海水Ca2+、K+和HCO3-与C l-的比主要围绕海水稀释线波动,表明沿海表层海水流动缓慢,受表层海水蒸发和当地沿岸污染河水排泄的长期累积影响;靠近深圳湾的5件西海岸海水样品成分与东海岸表层海水相似。  相似文献   

17.
中亚成矿域斑岩铜矿床基本特征   总被引：9，自引：2，他引：7  
中亚成矿域发育许多大型和超大型斑岩铜矿床,是世界上重要的斑岩铜矿成矿域。我们对9个大型和超大型斑岩铜矿床进行了研究,包括地质特征、含矿岩体地球化学、SIMS锆石U-Pb定年和成矿流体成分等,结合前人成果,我们认为中亚成矿域斑岩铜矿床具有如下特点:(1)成矿时代为古生代和中生代,成矿高峰期为泥盆纪和石炭纪;(2)含矿岩浆为钙碱性中酸性岩浆和少量的碱性岩浆,含矿岩体为花岗闪长岩、闪长岩、英云闪长岩和少量的二长岩;(3)含矿岩浆大多数源于新生的洋壳,少量有古老的基底物质和围岩物质参与;(4)成矿构造背景主要为岛弧,少量为陆缘弧和岛弧向陆缘弧过渡的环境;(5)矿床可分为三类,包括斑岩型Cu-Au、Cu(Au,Mo)和Cu-Mo矿床;(6)成矿流体可分为两类,包括氧化性H2O-Na Cl-CO2-SO2体系和少量的还原性H2O-Na Cl-CH4-CO2体系;(7)成矿系统可分为三类,包括简单的斑岩系统和少量的斑岩-矽卡岩成矿系统和斑岩-浅成低温热液成矿系统。  相似文献   

18.
Authigenic ferromanganese formations in sediments from two horizons (0–10 and 240–250 cm) located in the low/high bioproductive transitional zone of the Pacific Ocean were studied. In addition to the compositionally different two types of micronodules, crusts and ferromanganese nodules were detected in the surface horizon (0–1 cm). Three size fractions (50–100, 100–250, and 250–500 μm) of manganese micronodules were investigated. In terms of surface morphology, color, and shape, the micronodules are divided into the dull round (MN1) and angular lustrous (MN2) varieties with different mineral and chemical compositions. The dull MN1 are enriched in Mn and depleted in Fe as compared with the lustrous MN2. The Mn/Fe value in the dull MN1 varies from 13 to 14. Asbolane-buserite and birnessite are the major manganese minerals in them. The lustrous MN2 is mainly composed of vernadite with Mn/Fe = 4.3–4.8. Relative to the dull MN1, fraction 50–100 μm of the lustrous MN2 is enriched in Fe (2.6 times), W (1.8), Mo (3.2), Th (2.3), Ce (5.8), and REE (1.2–1.8). Relative to counterparts from the dull MN1, separate fractions of the lustrous MN2 are characterized by a greater compositional difference. For example, increase in the size of micronodules leads to decrease in contents of the following elements: Fe (by 10 rel %), Ce (2 times), W (2.1 times), Mo (2.2 times), and Co (1.5 times). At the same time, one can see increase in contents of other elements: Th and Cu (2.1 times), Ni (1.9 times), and REE (1.2–1.6 times). Differences in the chemical and mineral compositions of MN1 and MN2 fractions can be related to alternation of oxidative and suboxidative conditions in the sediments owing to the input of a labile organic matter, which serves as the major reducer, and the allochthonous genesis of MN2.  相似文献   

19.
The bronzite—chromite-anorthite assemblage of the F—unit(Cameron & Emerson, 1959) from the Critical Zone of theBushveld Igneous Complex, was examined with the aid of an electrolyticcell designed after Sato (1971). The resultant fO2-T data reveala last equilibration at an fO2 value of 1011·82 ±·40 atm and at a temperature of 1091 ± 35 °C.These fO2-T data when compared with: (1) a one atmosphere quenching—technique solidus determinationof 1110 ± 5 °C, (2) the Bushveld plagioclase compositional trends (Cameron,1970), (3) Bushveld petrofabric examinations (Cameron, 1969) (4) phase equilibria in the system CaO–MgO–FeO–CaAl2Si2O8–SiO2(Roeder & Osborn, 1966), (5) phase equilibria in the system CaAl2Si2O8–NaAlSi3O8–SiO2–MgO–Fe–O2–H2O–CO2(Eggler, 1974), all support the idea that the Eastern Bushveld magma was notappreciably differentiating in the middle Critical Zone betweenF and the L Horizons, an accumulation of nearly 220 meters.  相似文献   

20.
三峡库区奉节县宝塔坪小区大型复杂滑坡特征及成因机制   总被引：12，自引：1，他引：11  
张加桂 《地质论评》2000,46(4):431-436
奉节县新城宝塔坪小区的地质灾害问题是当前学术界关注的焦点,也是库区具有普遍性问题。本文首次提出,在小区发育有５个复杂结构的滑坡。滑坡具３种成因：（１）碎裂－溶蚀－杏黄色泥质条带发育－滑坡;（２）碎裂－溶蚀－Ｔ２ｂ＾２粉砂质泥岩顶层泥化－滑坡;（３）Ｔ２ｂ＾４泥岩溶蚀－滑坡。岩溶蚀作用为主导作用。断裂的发育为溶蚀作用提供了通道。  相似文献   

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