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1.
《矿物岩石》2016,(4)
针对佛子冲地区产出的正长花岗岩进行锆石LA-ICP-MS锆石U-Pb同位素年代学研究,结果表明,该岩体的形成年龄为170.8 Ma±6.3 Ma,时代为中侏罗世。岩石地球化学研究表明该岩石具有高钾钙碱性特征(K_2O+Na_2O=8.64%~9.62%,σ=2.44~2.69),准铝—弱过铝质(A/CNK=1.01~1.04),稀土含量高(ΣREE=273×10~(-6)~439×10~(-6),平均323×10~(-6)),LREE强烈富集,HREE轻度富集(La/Yb)N=10.87~16.21,平均13.68),较强的Eu负异常(δEu=0.18~0.26),总体呈向右缓倾斜的海鸥式,微量元素蛛网图上出现强烈富集Rb,Th,U,Pb,而亏损Ba,Sr,P,Ti,Eu,结合花岗岩成因类型判别图解确定其为A型花岗岩。综合区域上的研究成果,佛子冲中侏罗世正长花岗岩进一步佐证了华南地区在侏罗纪时,岩石圈发生了伸展作用,区域上是太平洋板块向西俯冲的一个地质响应。 相似文献
2.
塔里木盆地西北缘早二叠世后碰撞花岗质岩浆活动及其构造意义 总被引：1，自引：0，他引：1
塔里木地块西北缘的阔什布拉克钾长花岗岩富碱(Na_2O+K_2O平均8.36%8%),富钾(K_2O/Na_2O=1.27～1.47),准铝质(A/CNK=0.82～0.88),属于高钾钙碱性系列岩浆岩。岩石的稀土含量较高(∑REE=263.90×10~(-6)～445.75×10~(-6)),富集Th、U、Ta、Nb、Hf和Y等高场强元素和大离子亲石元素Rb,具有强的负Eu异常(δEu=0.003～0.019),富集高不相容元素(Zr+Nb+Ce+Y=368×10~(-6)～531×10~(-6)350×10~(-6)),高Ga(Ga/Al×10 000=4.17～4.722.6),显示出A型花岗岩的地球化学特征。岩石Th/U比值(平均为3.86)、Nb/Ta比值(平均为12.75)和Rb-Th富集、Ti亏损指示其壳源成因。对花岗岩进行的LA-ICP-MS微区原位锆石U-Pb定年结果表明,花岗岩的结晶侵位年龄为275.4±2.8 Ma。综合西南天山与塔里木盆地早二叠世花岗质岩浆活动的特点,认为早二叠世西南天山的后碰撞岩浆活动不仅在西南天山内部引起了强烈的花岗质岩浆活动,而且对塔里木地块西北边缘的花岗质岩浆活动也有显著的影响。阔什布拉克A型花岗岩也说明西南天山地区的碰撞造山作用在275.4±2.8 Ma之前已经趋于结束,以南天山洋盆为代表的古亚洲洋已基本结束了其演化历史。 相似文献
3.
前人对扬子地块西缘新元古代I型和S型花岗岩开展了深入的研究工作,但有关A型花岗岩的研究则鲜有报道,其岩石成因及大地构造意义仍存较大争议。文章选择最新发现的泸沽A型花岗岩体为研究对象,开展系统的LA-ICP-MS锆石U-Pb年代学、岩石学和地球化学研究,探讨其成因机制和地质意义。泸沽花岗岩由钾长花岗岩和二长花岗岩组成,LA-ICP-MS锆石U-Pb年代学分析显示其结晶年龄分别为(806±5)Ma和(815±5)Ma,属新元古代岩浆活动产物。岩石具有高硅(SiO_2=71.2%~76.1%)、高碱(K_2O+Na_2O=6.73%~8.95%)、高K_2O/Na_2O比值(1.89~3.60)和强过铝质(A/CNK=1.07~1.49)的特征。[FeO~T/(FeO~T+Mg O)]-SiO_2和[(Na_2O+K_2O)-CaO]-SiO_2图解均指示泸沽花岗岩为铁质碱钙性A型花岗岩。泸沽花岗岩具有较高的稀土元素含量(∑REE=221×10~(-6)~387×10~(-6)),具有轻稀土富集而重稀土亏损的特征((La/Yb)N=3.42~9.69),具有明显Eu的负异常(δEu=0.10~0.34)。泸沽花岗岩具有较高的Zr、Nb、Ce和Y含量,具有较高的Ga/Al、Y/Nb、Yb/Ta和Ce/Nb比值,显示出典型的A2型花岗岩特征。综合元素地球化学及区域地质资料,文章提出泸沽新元古代铝质A2型花岗岩起源于新元古代早期俯冲造山过程中的变泥质岩熔融。 相似文献
4.
塔吉里霞隆花岗闪长岩体位于冈底斯构造岩浆岩带西段,拉萨地块中西部。岩石w(SiO_2)=63.38%~72.56%;w(Al_2O_3)=13.85%~15.73%;Alk(K_2O+Na_2O)=5.12%~6.79%;w(K_2O)/w(Na_2O)=0.67~1.32;A/CNK=0.90~1.02,属Ⅰ型弱过铝质高钾钙碱性系列。稀土总量∑REE=128.34×10~(-6)~167.25×10~(-6),LREE/HREE=6.94~10.73,轻稀土富集重稀土亏损,配分曲线呈右倾型;δEu=0.69~0.86,弱负铕异常。岩石具有富集Rb、Th、K等大离子亲石元素,而亏损Ba、U、Nb、P等高场强元素的特征,岩石显示出岛弧火山岩亲缘性。锆石U@b定年结果表明,塔吉里霞隆岩体主要侵位于126.3±1.1Ma,属早白垩世晚期。塔吉里霞隆花岗闪长岩显示出壳幔混合源特征,班公湖-怒江洋壳岩石圈的南向俯冲和随后发生的板片回转可以较好的解释岩体成因。 相似文献
5.
对秦祁结合部位宝鸡地区香泉正长花岗岩进行了LA-ICP-MS锆石U-Pb年龄和岩石地球化学研究。结果显示,锆石~(206)Pb/~(238)Pb年龄加权平均值为410±5Ma(MSWD=0.20,n=18),限定该岩体的形成时代为早泥盆世。香泉正长花岗岩具有高硅(SiO_2=69.63%~73.94%)、富钾(K_2O=4.24%~4.88%,K_2O/Na_2O=1.23~1.44)、富铁(TFe_2O_3=2.10%~3.70%,TFe_2O_3/MgO=3.88~6.84)、低镁(MgO=0.31%~0.94%)、低磷(P_2O_5=0.08%~0.21%)的特征,属准铝质、高钾钙碱性系列。香泉正长花岗岩稀土元素含量较高(318×10~(-6)~499×10~(-6)),表现出明显的负Eu异常(δ Eu=0.37~0.46),富集Rb、Th、Zr、Sm、Ga(10000×Ga/Al=2.59~2.93)等微量元素,贫Ba、Nb、Ta、Sr,整体表现出A型花岗岩特征。结合区域资料认为,香泉正长花岗岩形成于造山后环境,为低压环境下长英质地壳物质部分熔融成因。 相似文献
6.
松辽盆地西缘早白垩世伸展事件：流纹岩锆石U Pb年龄、地球化学研究 总被引：4，自引：0，他引：4
为研究松辽盆地西缘大兴安岭早白垩世火山岩的构造属性,对研究区内流纹岩开展锆石U-Pb测年和地球化学测定。锆石U-Pb定年结果显示,流纹岩形成于131.6±0.6~123.9±1.7Ma,属早白垩世。主量元素分析表明,流纹岩具高硅(SiO_2=69.08%~79.58%)、富碱(K_2O+Na_2O=5.93%~9.76%,平均为8.14),富钾(K_2O/Na_2O大于1.0,平均为2.14)、贫钙镁(平均CaO为0.60、MgO为0.27)和高FeOT/MgO(平均为6.77)比值的特征,属过铝质(A/CNK=1.35~1.78)高钾钙碱性—钾玄武岩系列岩石。据微量元素地球化学特征将其划分为两组:Ⅰ组流纹岩稀土元素总量较高(∑REE介于149.04×10~(-6)~213.18×10~(-6)之间,平均为172.35×10~(-6)),轻稀土元素(LREE)富集、轻重稀土元素分馏较强[(La/Yb)_N=4.89~11.87,平均为7.75)],中等—弱负铕异常(δEu=0.54~0.88,平均为0.70),配分曲线右倾模式,强烈富集大离子亲石元素(LILE)Rb,Ba,Th,K和亏损高场强元素(HFSE)_Nb,Ta,P和Ti;Ⅱ组流纹岩以稀土总量(∑REE平均为142.60×10~(-6))相对较低,具相对较强的负铕异常(δEu=0.05~0.46,平均为0.27),配分曲线相对较平缓以及Ba,Sr,P,Ti元素的强烈亏损与Ⅰ组流纹岩相区别,两组流纹岩地球化学成分相关性较好,二者均有低的Sr(206×10~(-6))和高Yb(大于2)含量,具壳源和造山后花岗岩的特征。结合最新资料及本文研究成果,初步认为研究区流纹岩为地壳部分熔融的产物,之后经历强烈的矿物分离结晶作用,与蒙古—鄂霍次克造山后伸展作用有关。 相似文献
7.
《华北地质》2016,(3)
内蒙古赤峰市白音诺尔铅锌矿床是大兴安岭地区储量最大的铅锌矿床。该矿床位于白音乌拉火山机构的北部,矿区范围内出露二长花岗岩和花岗闪长(斑)岩侵入体,与黄岗梁组大理岩或结晶灰岩接触带附近发育系列矽卡岩,铅锌矿体主要产于透辉石矽卡岩中,属于矽卡岩型矿床。二长花岗岩地球化学显示富硅(SiO_2=68.98%~75.44%),高铝(Al_2O_3=12.49%~15.62%)、低镁(Mg=0.1%~1.25%),富碱(Na_2O+K_2O=7.73%~8.80%,Na_2O/K_2O=0.96~1.33)的特点,属于高钾钙碱性系列的准铝质花岗岩。稀土配分呈轻稀土富集型分布模式,稀土总量变化于127.4×10-6~145.95×10-6之间,存在较弱的正Ce异常和明显的Eu负异常,微量元素表现为Rb、Th、K等大离子亲石元素富集,而Nb、Ta、P、Ti等高场强元素亏损的特征。在Rb-(Y+Nb)、Rb-(Yb+Ta)构造环境判别图解中,所有样品均落入火山弧花岗岩构造环境中。两件二长花岗岩锆石LA-ICP-MS法U-Pb年龄为254.8±1.6 Ma和245.6±3.5 Ma,将岩浆岩侵入及相关的成矿作用限定为古生代末期,推测在晚古生代末期古亚洲洋局部残留洋盆的俯冲是形成白音诺尔二长花岗岩及成矿的动力学机制。 相似文献
8.
大兴安岭富克山地区兴华渡口群地球化学及锆石U-Pb年龄特征 总被引：1，自引：0，他引：1
对富克山地区兴华渡口群岩石地球化学、锆石LA-ICP-MS U-Pb年代学研究结果表明,5件样品:Si O_2=50.24%~54.66%,Al_2O_3=14.41%~17.36%,Ca O=6.5%~8.68%,Na_2O=2.62%~4.67%,K_2O=1.36%~2.29%,Na_2O+K_2O=4.09%~6.3%,稀土总量∑REE=108.33×10~(-6)~240.28×10~(-6),稀土元素配分模式表现为轻稀土元素富集,重稀土元素相对亏损的右倾型曲线,具有弱的负铕异常。富集大离子亲石元素(K、Rb、Ba),相对亏损高场强元素(Nb、Ta、Zr、P、Ti等)。锆石U-Pb测年结果表明其岩浆形成时代为晚寒武世—早奥陶世(486.6±3.3 Ma)。富克山地区兴华渡口群原岩岩石组合类型为基性火山岩,为一套晚寒武世—早奥陶世活动大陆边缘火山建造。 相似文献
9.
江西彭山锡多金属矿集区隐伏花岗岩体的岩石地球化学、锆石U-Pb年代学和Hf同位素组成 总被引：8，自引：7，他引：1
本文对江西彭山锡多金属矿集区隐伏花岗岩体进行了详细的锆石U-Pb年代学、Hf同位素组成和岩石地球化学研究。SHRIMP和LA-ICP-MS锆石U-Pb定年表明,该岩体年龄为128~129Ma,属燕山晚期岩浆活动的产物。详细的地球化学分析显示,彭山隐伏花岗岩体具有高硅(SiO2=75.42%~76.46%)、富碱(Na2O+K2O=7.93%~8.35%,K2O/Na2O=1.32~1.61)的特征,极度贫Mg(普遍MgO=0~0.07%),贫Ca(CaO=0.37%~0.69%),弱过铝质(A/CNK=1.04~1.11),富集Rb、Th、U等大离子亲石元素及Hf、Nb等高场强元素,强烈亏损Sr、Ba、Eu、P、Ti。稀土总量偏低(∑REE=41.18×10-6~85.06×10-6),强烈的Eu负异常(Eu/Eu*=0.05~0.11)。104×Ga/Al比值变化于2.75~4.04,平均值为3.19。这些特征均不同于典型的A型和S型花岗岩。岩石学和地球化学特征指示该岩体可能是一个高分异的I型花岗岩。该花岗岩中锆石εHf(t)值偏高,主要集中在-0.6~-4.5,显示在成岩过程中有地幔组分的参与,属壳幔混源花岗岩,推测该岩体的形成可能与燕山晚期华南岩石圈伸展拉张环境有关。 相似文献
10.
茶庵岩体位于秦岭造山带东段,岩体的主要岩性为二云母花岗岩。岩石地球化学分析结果显示,茶庵岩体w(SiO2)为73.22%~75.29%,w(K_2O)为4.11%~4.74%,w(Na_2O)为3.68%~4.34%,w(Al_2 O_3)为13.90%~15.31%,具有高钾钙碱性和过铝质(ACNK=1.03~1.17)特征。岩石稀土总量较低(22.02×10-6~84.18×10-6),轻稀土元素相对富集,重稀土元素相对亏损,具有Eu的负异常,岩体富集Rb、U、Hf和Y,亏损Ba、Nb、Ta和Ti,显示出I型花岗岩的特点,形成于碰撞造山后的伸展构造环境。 相似文献
11.
东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。 相似文献
12.
The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads 总被引：3，自引：1，他引：2
Clemente Irigaray Francisco Lamas Rachid El Hamdouni Tomás Fernández José Chacón 《Natural Hazards》2000,21(1):65-81
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning. 相似文献
13.
郯庐断裂南段研究进展与断裂性质讨论 总被引：13，自引：3，他引：13
据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。 相似文献
14.
15.
Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
16.
某高速公路下伏煤矿采空区稳定性分析 总被引：10，自引：0，他引：10
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。 相似文献
17.
Dean S. Oliver 《Mathematical Geology》1998,30(7):911-933
In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix. 相似文献
18.
Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers 《《幕》》2008,31(3):315-318
The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs. 相似文献
19.
Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
20.
正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the 相似文献