天然气水合物系统的环境效应

环境效应是天然气水合物科学体系中重要一环,同时,有关该领域的调查研究也是人类安全、环保、经济、科学地利用水合物资源的可靠保证。海底天然气水合物所孕育的独特的生态系统、与之关联的重大地学、环境问题以及资源的勘探开发均是充满魅力而又富有挑战的科学新领域。梳理了当前全球范围内有关水合物环境效应的大部分研究工作,综述了与天然气水合物环境有关的生物效应、化学效应和物理效应的研究现状及内容,着重强调了与该领域相关的基础问题和焦点问题,展望了该领域未来发展的趋势,希望藉此为我国的水合物环境效应调查与评价工作向纵深推进提供参考依据,并能引起广大研究者的兴趣与重视。     

甘肃省明舒井地区高光谱蚀变异常及找矿分析

正明舒井地区位于甘肃省北西侧,敦煌市北侧、瓜州县北西侧。前人在该区及周边区域开展了区调、矿调及相关多金属矿的勘查工作(王瑞军等,2014,2017),在遥感地质方面,仅开展了多光谱遥感的应用工作,而针对高光谱遥感的研究工作还未开展。明舒井地区基岩出露好、地形起伏小、切割弱,地表蚀变发育,矿床、矿点分布较多,具备开展高光谱遥感技术的地质和自然地理条件,有利于发挥高光谱的技术优势。     

缩短核磁共振测定冻土未冻水含量实验时间的方法

为利用核磁共振(NMR)技术更快地测试得到冻土中未冻水的含量, 首先对传统的单试样测试方法进行了分析, 探究了其实验时间过长的原因. 然后, 基于传热学中的集总参数法, 研究了小体积试样在空气中以自然对流传热为冷却方式的温度变化特征. 根据试样温度与时间的对应关系, 提出了多试样连续测试法. 最后, 以一种黏土为例, 分别利用多试样连续测试法和单试样测试法测量了土样冻结过程中NMR信号强度随温度变化的关系. 实验结果表明: 二者的测量结果非常接近, 但连续测试法耗费的时间非常少. 综合比较两种利用NMR技术所耗费的时间和实验结果的精确程度, 多试样连续测试法是可行的.     

Trace element zoning in pyroxenes from ODP Hole 735B gabbros: diffusive exchange or synkinematic crystal fractionation?

Major and trace element profiles of clinopyroxene grains in oceanic gabbros from ODP Hole 735B have been investigated by a combined in situ analytical study with ion probe, and electron microprobe. In contrast to the homogeneous major element compositions, trace elements (REE, Y, Cr, Sr, and Zr) show continuous core to rim zoning profiles. The observed trace element systematics in clinopyroxene cannot be explained by a simple diffusive exchange between melts and gabbros along grain boundaries. A simultaneous modification of the melt composition is required to generate the zoning, although Rayleigh fractional crystallization modelling could mimic the general shape of the profiles. Simultaneous metasomatism between the cumulate crystal and the porous melt during crystal accumulation is the most likely process to explain the zoning. Deformation during solidification of the crystal mush could have caused squeezing out of the incompatible element enriched residual melts (interstitial liquid). Migration of the melt along grain boundaries might carry these melt out of the system. This process named as synkinematic differentiation or differentiation by deformation (Natland and Dick in J Volcanol Geotherm Res 110(3–4):191–233, 2001) may act as an important magma evolution mechanism in the oceanic crust, at least at slow-spreading ridges.     

辽宁省红旗营子铅锌矿床岩脉与含矿构造关系研究

文章通过野外对岩脉和含矿构造特征的观察研究,得出它们之间的先后顺序为：NE向花岗斑岩脉→闪长玢岩→矿化构造,NW向岩脉最晚.早期的NE向岩脉为成矿物质提供了运移通道和最佳的容矿空间,并表现为构造矿化带常沿着岩脉产出.     

西准噶尔玛依拉山组志留纪玄武岩的地球化学特征及构造意义

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。     

贵州天柱磨山─油麻坳金矿化带地球化学特征及成矿作用

贵州天柱磨山油麻坳金矿化带地球化学特征及成矿作用＊张杰余大龙李明琴张先煜杨勇俊（贵州工业大学资源工程系，贵阳５５０００３）关键词金矿化带金矿地球化学金矿成矿作用黔东天柱本文主要研究了黔东天柱磨山—油麻坳金矿化带内主要类型岩石矿石的地质－地球化学特征，...     

Guandishan Granitoids of the Paleoproterozoic Lüliang Metamorphic Complex in the Trans-North China Orogen:SHRIMP Zircon Ages,Petrogenesis and Tectonic Implications

The Paleoproterozoic Liiliang Metamorphic Complex(PLMC)is situated in the middle segment of the western margin of the Trans-North China Orogen(TNCO),North China Craton(NCC). As the most important Iithological assemblages in the southern part of the PLMC,Guandishan granitoids consist of early gneissic tonalities,granodiorites and gneissic monzogranites,and younger gneissic to massive monzogranites.Petrochemical features reveal that the early gneissic tonalities and granodiorites belong to the medium-K calc-alkaline series;the early gneissic monzogranites are transitional from high-K caic-alkaline to the shoshonite series;the younger gneissic to massive monzogranites belong to the high-k calc-alkaline series,and all rocks are characterized by right-declined REE patterns and negative Nb,Ta,Sr,P,and Ti anomalies in the primitive mantle normalized spidergrams.SHRIMP zircon U-Pb isotopic dating reveal that the early gneissic tonalities and granodiorites formed at ～2.17 Ga,the early gneissic monzogranites at ～2.06 Ga,and the younger gneissic to massive monzogranites at ～1.84 Ga.Sm-Nd isotopic data show that the early gneissic tonalities and granodiorites have εNd(t) values of +0.48 to -3.19 with Nd-depleted mantle model ages (TDM)of 2.76-2.47 Ga,and early gneissic monzogranites have εNd(t) values of -0.53 to -2.51 with TDM of 2.61-2.43 Ga,and the younger gneissic monzogranites have εNd(t) values of -6.41 to -2.78 with a TDM of 2.69-2.52 Ga.These geochemical and isotopic data indicate that the early gneissic tonalities,granodiorites,and monzogranites were derived from the partial melting of metamorphosed basaltic and pelitic rocks,respectively,in a continental arc setting.The younger gneissic to massive monzogranites were derived by partial melting of metamorphosed greywackes within the continental crust.Combined with previously regional data,we suggest that the PaleOproterOzOic granitoid magmatism in the Guandishan granitoids of the PLMC may provide the best geologicaI signature for the complete spectrum of Paleoproterozoic geodynamic processes in the Trans-North China Orogen from oceanic subduction.through collisional orogenesis,to post-orogenic extension and uplift.     

新疆富蕴县恰库尔特—带碱性花岗岩的基本特征及形成的大地构造背景

恰库尔特一带的碱性花岗岩按侵入顺序和岩性可分为:晶洞(霓石)钾长花岗岩、(霓石)碱长花岗斑岩、霓石花岗岩.这些岩石大都含碱性暗色矿物.发育指示浅成特点的晶洞构造及文象结构,从矿物组合看岩石具贫水特征;岩石化学方面以高硅、高碱或过碱,贫铝、镁、钙为主要特征;岩石通常具有高的∑REE,其中以过碱性的霓石花岗岩为最高;轻稀土较重稀土富集,并具有强的负Eu异常;微量元素地球化学图谱表明,岩石相当于洋脊花岗岩,具有高钾、铷、钍的含量,而钡、钽、铌的富集程度相对较低.以上特征和区域构造分析表明,恰库尔特一带的碱性花岗岩为阿尔泰造山带造山作用结束以后于中晚三叠世的非造山环境下形成的A型花岗岩.     

PI-RADS v2.1联合PSA相关指标预测PSA灰区前列腺癌的价值研究

目的：探讨建立前列腺影像报告及数据系统（PI-RADS v2.1）联合前列腺抗原（PSA）相关衍生物的Logistic模型对PSA灰区（4～10ng/mL）前列腺癌（PCa）的诊断价值。材料与方法：回顾性分析经病理证实的49例前列腺癌（PCa）和118例非癌患者的资料,包括年龄、tPSA、fPSA、PI-RADS v2.1评分、PSAD、fPSA/tPSA。对组间有统计学差异的指标进行Logistic回归分析,确定PCa独立预测指标,并分别联合PI-RADS v2.1评分建立Logistic回归预测模型。通过受试者工作特性曲线（ROC）评价各模型的诊断效能。结果：①年龄、tPSA、fPSA在PCa与非癌组间无统计学差异,fPSA/tPSA、PSAD、PI-RADS v2.1评分有统计学差异。②Logistic回归分析显示PI-RADS v2.1评分、PSAD、fPSA/tPSA为PCa独立预测因子;拟建立预测模型,A模型：Logit（P）=-10.82+2.32×PI-RADS v2.1+11.89×PSAD;B模型：Logit（P）=-6.13+2.19×PI-RADS v2.1-12.02×fPSA/tPSA。ROC曲线下面积分别为0.918和0.893,均高于单独使用PI-RADS v2.1评分,差异具有统计学意义。其中A模型敏感度0.843、特异度0.829,较单独使用PI-RADS v2.1评分（敏感度0.767、特异度0.801）诊断效能最佳。结论：PI-RADS v2.1评分联合PSA相关指标建立的Logistic模型在PSA灰区前列腺癌的诊断效能均优于单独运用PI-RADS v2.1评分,能够避免不必要的穿刺活检,对优化临床治疗策略具有较好的指导作用。