副矿物的电子探针化学定年方法原理及应用   总被引：13，自引：0，他引：13  

张文兰王汝成  华仁民陈小明 《地质论评》2003,49(3):253-260

化学定年方法是利用电子探针分析副矿物中的U、Th、Pb含量而进行定年的一种新方法。基本原理是，假设可以忽赂矿物韧始铅，封闭体系中矿物的总铅含量代表U—Th衰变形成的放射性成因铅含量，即：Pb总＝^238U(e^λ238r-1) ^235U(e^λ235r—1) ^232Th(e^λ232r—1)，该方法可利用的副矿物包括：锆石、独居石、褐帘石、碘纪矿、铀石、钍石、晶质铀矿等。本文以华南西华山岩体漂塘花岗岩中的锆石为例，对该方法进行了尝试性的研究。分析结果计算表明，两颗锆石的平均年龄分别为143．9Ma和143Ma，与前人通过同位素方法获得的年龄基本相符。结果还显示，锆石颗粒从中心到边缘的年龄呈现从老到新的趋势。  相似文献   

裂缝宽度的定量计算及储层流体类型识别   总被引：2，自引：0，他引：2  

魏斌  卢毓周  乔德新  王晓锋  孙宝喜 《物探与化探》2003,27(3):217-219

在辽河测井公司完成的声电成像模拟井的基础上,利用声波成像测井资料建立了定量计算裂缝宽度的方法,并应用该方法评价储层裂缝参数,进而通过综合研究识别储层流体类型,在辽河油田复杂岩性储层取得了良好的应用效果.  相似文献   

起伏地形上规则二度体复重磁场正演和直接反演     

安玉林 《物探与化探》2003,27(4):284-291

上接211页13　n个无限薄板叠加场反演13.1　复场展开以Mj代替2Mmj和2fMgj,以F(S)代替G′(S)和T(S),得复场F(S)= nj=1Mjσj-S=- nj=1MjS-σj。(13.1)展开上式,即F(S)=-1(S-σ1)(S-σ2)…(S-σn)×{M1(S-σ2)(S-σ3)…(S-σn)+M2(S-σ1)(S-σ3)…(S-σn)+…+Mn(S-σ1)(S-σ2)…(S-σn-1)}。(13.2)根据(9.2)、(9.9)式有(S-σ1)(S-σ2)…(S-σn)=-1F(S){Φ1+Φ2+…+Φn};Φ1=M1{Sn-1-x1(1)Sn-2+x2(1)Sn-3-　　　　…+(-1)n-1x(n-1)(1)},Φ2=M2{Sn-1-x1(2)Sn-2+x2(2)Sn-3-　　　　…+(-1)n-1x(n-1)(2)},Φn=Mn{Sn-1-x1(n)S…  相似文献   

利用13X沸石分子筛净化含Pb~(2+)废水的实验研究   总被引：11，自引：0，他引：11  

马鸿文  肖万  陶红 《现代地质》2003,17(2):157-162

采用静态间歇法 ,实验研究了含Pb2 +废水的 pH值及吸附时间对 13X沸石分子筛吸附Pb2 +性能的影响 ,得出了最佳去除效果的优化条件为 :废水的 pH值接近中性 ,吸附时间 10min。通过吸附实验 ,确定了在Pb2 +初始浓度为 2 0mg/L的条件下 ,13X沸石对Pb2 +的吸附量为 2 1 4 2mg/g ,即每克沸石净化含Pb2 +废水的最大体积量约为 75 0mL。解析实验表明 ,加入沉淀剂 ,浓缩洗脱液中的Pb2 +即以PbS的形式生成沉淀 ,为回收金属铅提供了可能 ;13X沸石在循环使用 5次的条件下 ,对废水中Pb2 +的吸附率仍高达 98% ,重复使用性能良好。经处理后的净化水中Pb2 +的浓度小于 0 4mg/L ,显著低于国家废水排放标准GB8978 88的指标 ( 1 0mg/L)。 13X沸石对Pb2 +的主要吸附形式是离子交换和表面络合反应。  相似文献   

复杂地层超长桩施工技术研究     

吴失文 《中国煤田地质》2003,15(1):46-47

福州市新都会花园广场,其施工场地工程地质条件复杂,设计灌注桩深度为60m左右。针对复杂地层中超长灌注桩桩施工的技术难点、应采用的技术措施、以及成孔工艺进行了分析与研究,总结了在复杂地层超长桩施工中采用气举反循环回转加冲击施工技术及桩底后压浆技术的运用成效。  相似文献   

吉林省敦化地区晚三叠世碱性-亚碱性侵入杂岩体的地质特征及构造背景分析   总被引：2，自引：1，他引：2  

齐成栋  纪春华  韩江  聂立军 《吉林地质》2003,22(3):12-18

吉林省敦化地区以碱厂沟、三岔子、青林子岩体为代表的碱性-偏碱性侵入杂岩体,主要由碱性辉长岩、角闪碱长正长岩、石英正长岩和角闪碱长花岗岩等组成,具复合环状深成杂岩之特征。辉长岩KAr同位素年龄为224Ma①,角闪碱长正长岩UPb同位素年龄为(223±1)Ma,表明岩体形成时代为晚三叠世。岩石化学、地球化学特征表明岩浆源于上地幔物质的部分融熔,但并非典型大陆裂谷性质的碱性岩,其形成标志着区域上南北向古亚洲构造域碰撞造山已结束,开始进入稳定大陆裂谷的发展阶段,并预示着北东向滨太平洋构造域的开始。  相似文献   

The Fanshan Apatite-Magnetite Deposit in the Potassic Ultramafic Layered Intrusion, North China   总被引：1，自引：0，他引：1  

Chun Cheng  Shihua Sun 《Resource Geology》2003,53(2):163-174

Abstract. This article reviews work carried out on the Fanshan layered apatite (-magnetite) deposit, which occurs in the Fanshan complex, a potassic ultramafic-syenite layered intrusion located in North China. The Fanshan complex intruded into Proterozoic sedimentary rocks in the early Triassic. The complex comprises First- to Third-Phase Intrusives. The First-Phase Intrusive includes rhythmic Units 1 to 9, which mainly consist of clinopyroxenite and biotite clinopyroxenite. The apatite (-magnetite) deposit is situated near the top of rhythmic Unit no. 6 of the First-Phase Intrusive.
The economical deposit comprises Orebody II and Orebody III. Orebody II, situated at the top of Unit no. 6, consists of two kinds of layer: one magnetite-apatite rock layer at the top and a few apatite rock layers at the bottom. Orebody III is situated several meters below Orebody II, and consists of an apatite rock layer.
There is controversy over the ore formation mechanism, the temperature and pressure of the magma intrusion, and the origin of the magma (including the possibility of magma immiscibility). We review these problems of this unique apatite (-magnetite) magmatic deposit.  相似文献   

关于赣西武功山地区构造问题的讨论   总被引：5，自引：0，他引：5  

刘细元  衷存堤 《华东地质学院学报》2003,26(3):249-253

赣西武功山地区发育的穹窿状变形变质体的组成结构和成因机制与经典的变质核杂岩有相似之处，它们由内核和外壳组成，并具三层式结构特征。但其内核主要为花岗岩，核内和核外的地层几乎同时代，并无“古老变质核”，它的形成机制主要是岩浆底辟强力侵住引起地壳局部隆升和伸展滑覆。本文将赣西武功山地区的穹窿状变形变质体改称为“武功山岩浆核杂岩”。  相似文献   

The origin of K-feldspar megacrysts hosted in alkaline potassic rocks from central Italy: a track for low-pressure processes in mafic magmas     

Giulia Perini  Frank J. Tepley  III  Jon P. Davidson  Sandro Conticelli   《Lithos》2003,66(3-4):223-240

In situ Sr-isotope and microchemical studies were used to determine the provenance of K-feldspar megacrysts hosted in mafic alkaline potassic, ultrapotassic rocks and in differentiated rocks from two nearby volcanic apparatus in central Italy.

At Monte Cimino volcanic complex, mafic leucite-free ultrapotassic megacryst-bearing rocks of olivine latitic composition are associated with evolved latite and trachyte. Here, latites and trachytes straddle the sub-alkaline field. Age-corrected ⁸⁷Sr/⁸⁶Sr values (Sr_i) of the analysed Cimino olivine latites vary from 0.71330 and 0.71578 and strongly increase at constant Mg value. Latite and trachyte have lower Sr_i than olivine latites ranging between 0.71331 and 0.71361. Sr_i of K-feldspar megacrysts from olivine latites are between 0.71352 and 0.71397, but core and rim ⁸⁷Sr/⁸⁶Sr ratios within individual megacryst are indistinguishable. In all the mafic rocks, the megacrysts are not in isotopic equilibrium with the hosts. K-feldspar megacrysts from both the latite and trachyte have similar Sr-isotope compositions (Sr_i=0.71357–0.71401) to those in the olivine latites. However, Sr_i of megacryst in the trachyte vary significantly from core to rim (Sr_i from 0.71401 to 0.71383). As with the olivine latites, the K-feldspar megacrysts are not in isotopic equilibrium with bulk rock compositions of the latite or trachyte.

At Vico volcano, megacryst-bearing rocks are mafic leucite-free potassic rocks, mafic leucite-bearing ultrapotassic rocks and old trachytic rocks. The mafic leucite-bearing and leucite-free rocks are a tephri-phonolite and an olivine latite, respectively. A megacryst in Vico trachyte is isotopically homogeneous (Sr_i CORE=0.71129, RIM=0.71128) and in equilibrium with the host rock (Sr_i bulk ROCK=0.71125). Sr_i of megacryst from tephri-phonolite is clearly not in isotopic equilibrium with its host (Sr_i bulk ROCK=0.71158), and it increases from core (Sr_i=0.71063) to rim (Sr_i=0.71077). A megacryst in Vico olivine latite is isotopically homogeneous (Sr_i CORE=0.71066, RIM=0.71065), but not in equilibrium with the host rock (Sr_i bulk ROCK=0.71013).

The Sr isotope microdrilling technique reveals that Cimino megacrysts were crystallised in a Cimino trachytic magma and were subsequently incorporated by mixing/mingling processes in the latitic and olivine latitic melts. A model invoking the presence of a mafic sub-alkaline magma, which was mixed with the olivine latite, is proposed to justify the lack of simple geochemical mixing relation between Cimino trachytes and olivine latites. This magmatological model is able to explain the geochemical characteristics of Cimino olivine latites, otherwise ascribed to mantle heterogeneity.

The similarity of core Sr_i of megacrysts hosted in Vico tephri-phonolite and olivine latite suggests that the K-feldspar megacrysts are co-genetic. Isotopic equilibrium between megacryst and Vico host trachyte indicates that the trachyte is the parent of this megacryst. On the contrary, the megacrysts hosted in tephri-phonolite and olivine latite do not derive from the old trachytic magma because no diffusion process may explain the core to rim Sr isotope increase of the xenocryst hosted in the tephri-phonolite. The megacrysts hosted in the Vico mafic rocks might derive from a trachytic melt similar in composition to the old Vico trachytes.  相似文献   

王安镇岩体岩石地球化学特征及成因探讨   总被引：14，自引：14，他引：14  

蔡剑辉  阎国翰  常兆山  王晓芳  邵宏翔  储著银 《岩石学报》2003,19(1):81-92

王安镇岩体是我国东部太行山-大兴安岭中生代构造岩浆带中规模最大、岩石类型最多的代表性岩体之一,该岩体由早期、主期和晚期三期岩石组成。本文通过对王安镇岩体三期岩石主量元素、稀土元素、微量元素和Sr、Nd、Pb同位素的系统研究,发现该岩体主期岩石(花岗闪长岩、二长花岗岩和少量石英闪长岩)具有与埃达克岩类似的独持的岩石地球化学特征:SiO_2≥56％,Al_2O_3≥15％,低Y(4.20～12.68μg/g)而高Sr(518～861μg/g)和Sr/Y值(60.19～178.10),LREE强烈富集(La/Yb)_N=34.06～76.91,HREE强烈亏损Yb=0.44～1.00,Sr、Eu无明显异常,高场强元素(如Nb,Hf和Ti)相对亏损,I_(Sr)值为0.7060,ε_(Nd)(t)均为负值(-16.29～-14.27),ε_(Sr)(t)均为正值(+23.7～+25.0),应属于埃达克质岩,但又与俯冲板片熔融形成的埃达克岩的地球化学组成明显不同,推测可能是由于晚中生代区域内热地幔物质是“蘑菇云”状上涌,使热侵蚀面抬升到地壳底部,导致玄武质下地壳在高压下发生部分熔融的产物。而早期和晚期岩石则属于非埃达克质岩,早期为基-中性岩石(角闪石岩、辉长岩和闪长岩),富Mg、Fe,LREE富集,Eu呈正异常,富集相容元素而亏损不相容元素,I_(Sr)=为0.7056,ε_(Nd)(t)=-16.72～-10.92,推测是华北地台岩石圈富集地幔部分熔融的产物,  相似文献