甜水海地块寒武纪安山岩的地球化学和年代学研究:对西昆仑-喀喇昆仑造山带原特提斯洋演化的启示

甜水海地块作为西昆仑-喀喇昆仑造山带重要的组成部分,夹持于麻扎-康西瓦板块缝合带和洪山湖-乔尔天山板块缝合带之间,其构造属性的探讨对认知西昆仑地区早古生代地质演化具有重要的科学意义。笔者在甜水海地块中部麻扎地区通过野外填图新发现并厘定出一套火山岩-沉积岩组合,主要由安山岩、英安岩、流纹岩及其火山碎屑岩和少量沉积岩组成;与安山岩互层产出的英安岩和流纹岩锆石U-Pb年龄为519~513Ma,表明这套火山-沉积地层形成于中寒武世。该火山岩套的地球化学特征为：安山岩SiO₂含量为57.0%~67.2%,具有高MgO（1.91%~7.17%）含量和Mg^#值（39.1~65.3,平均值为55.0）,较高Cr（31.0×10^-6~190×10^-6）和Ni（12.2×10^-6~121×10^-6）含量,低FeO^T/MgO比值（1.12~3.26）,低Al₂O₃（13.7%~17.3%）和K₂O（1.12%~5.52%）含量的特征,属于低铁钙碱系列高镁安山岩-镁安山岩;英安岩较安山岩SiO₂含量高（63.8%~71.8%）,具有相似的Al₂O₃（13.4%~15.4%）含量,低MgO（0.28%~1.19%）含量和Mg^#值（9.98~36.5,平均值为25.3）,低Cr（11.5×10^-6~25.2×10^-6）和Ni（4.33×10^-6~11.8×10^-6）含量,高FeO^T/MgO比值（3.64~18.9）和K₂O（4.84%~9.27%）含量的特征,属于高钾钙碱性系列。安山岩和英安岩总体表现出右倾轻稀土富集分配模式,富集Rb、Ba、K、Th等大离子亲石元素,亏损Nb、Ta、Ti高场强元素,具有典型的岛弧岩浆岩特征。野外调查表明,安山岩与英安岩在空间上相邻,呈互层产出,且它们都出露于中寒武系地层中,暗示了二者在成因上紧密相联。岩石地球化学特征指示了安山岩和英安岩可能源于富集地幔楔不同比例的部分熔融作用,所产生的岩浆在上升过程中又遭受了不同比例的地壳混染。推测麻扎地区寒武纪火山岩形成于原特提斯洋向南俯冲消减机制下的岛弧构造环境,同时结合区域资料,认为在寒武纪甜水海地块存在两期岩浆作用,在早寒武系末期（~520Ma）原特提斯洋发生双向俯冲,甜水海地块北缘转化为活动大陆边缘。     

辽西早白垩世义县组砖城子层湖相碳酸盐岩地球化学特征及古湖泊学沉积意义

辽西义县盆地早白垩世义县组陆相湖盆沉积中常发育多个薄层碳酸盐岩沉积层,碳酸盐岩地球化学的研究对揭示湖盆沉积古环境具有重要理论意义。义县组砖城子层英窝山剖面湖相碳酸盐岩分析结果显示,岩石δ¹³C值为-3.44×10^-3~0.27×10^-3,均值为-1.21×10^-3;δ¹⁸O值为-15.73×10^-3~-9.93×10^-3,均值为-10.88×10^-3。盐度Z值变化范围114.78~122.39。碳酸盐岩主量元素分析表明,w（CaO+MgO+LOI）=53.38%~97.04%,均值71.15%;陆源组分w（Al₂O₃+SiO₂+Fe₂O₃）=2.19%~44.87%,均值为27.77%;x（Mg）/x（Ca）摩尔比介于0.92~1.01。碳酸盐岩微量元素地球化学提供了古湖泊学的古盐度、氧化还原和古气候证据。w（Sr）=110.4×10^-6~1360.2×10^-6,w（Ga）=0.152×10^-6~14.13×10^-6,w（Sr）/w（Ba）=0.34~131.49（多数>1）,指示沉积湖泊水体为咸水环境;氧化-还原指标w（V）/w（V+Ni）＝0.51~0.83,w（V）/w（Cr）＝1.59~8.28（多数>2.0）,w（U）/w（Th）=0.39~10.24,且变化范围较大,指示为半封闭—封闭的缺氧还原强分层水体沉积环境;w（Sr）/w（Cu）=54.94~1260.71,均值为213.79,反映炎热干旱气候类型。义县组砖城子层沉积期湖泊为干旱古气候背景下的半咸水—咸水、缺氧还原强分层的半封闭—封闭型。     

藏南米拉山地区中新世埃达克质岩石的年代学、地球化学和成因

中新世是青藏高原隆升、增厚的重要时期,并且在这一时期内拉萨地块广泛发育碰撞后岩浆岩。本文对南拉萨地块米拉山地区的钙碱性钾质火山岩进行了锆石U-Pb年代学、Lu-Hf同位素和全岩主量、微量元素的测定与系统研究。米拉山中新世火山岩为粗面英安岩、英安岩和流纹岩（SiO₂=59.89%~71.78%）。锆石U-Pb定年结果为16.1±0.2Ma~20.4±0.3Ma,表明其喷发时代为中新世。岩石具有较高的Al₂O₃含量（13.54%~16.31%）,低MgO（0.46%~1.95%）、高Sr（388×10^-6~804×10^-6）、低Y（6.55×10^-6~11.20×10^-6）和Yb（0.70×10^-6~1.07×10^-6）的特征,具有较高的Sr/Y值（51~80）、低相容元素（Cr=4.26×10^-6~32.53×10^-6,Ni=4.16×10^-6~25.75×10^-6）和弱Eu负异常。岩石具有轻稀土元素和Rb、Th、U、K等元素富集、重稀土元素和高场强元素Nb、Ta、Ti亏损的特征。米拉山中新世火山岩显示出埃达克质岩石的地球化学特征,可能来自于的镁铁质加厚下地壳的部分熔融,推测下地壳源区是石榴石角闪岩。锆石ε_Hf（t）值为+2.2~+7.8,表明源区为新生地壳物质,有俯冲板片熔体加入。米拉山中新世火山岩的喷发时代与米拉山断裂活动时间一致,二者可能同为拉萨地块岩石圈拆沉的结果。     

云南格咱岛弧普朗斑岩型铜矿年代学、岩石矿物学及地球化学研究

普朗斑岩型铜矿床位于西南三江构造火成岩带义敦岛弧南端,是晚三叠世甘孜-理塘洋壳向德格-中甸陆块俯冲的产物,是我国近年来印支期新发现的超大型铜多金属矿床。与成矿关系密切的斑岩体的岩石类型主要为石英闪长玢岩和石英二长斑岩,通过系统的锆石U-Pb测年方法获得,含矿石英闪长玢岩的形成年龄为219.6±3.5Ma,石英二长斑岩的形成年龄为212.8±1.9Ma。岩石地球化学特征表明,SiO₂含量为61.99%~70.58%,Al₂O₃含量为10.84%~14.96%,MgO含量为1.5%~3.96%,A/CNK值为0.80~1.08,为准铝质-弱过铝质。岩石轻稀土较富集,轻重稀土分馏明显((La/Yb)_N=11.41~16.48),δEu(0.76~0.9)值无明显异常。微量元素表现出具较高的Sr(244×10^-6~845×10^-6)、Ba(543×10^-6~2237×10^-6)含量,Y、Yb含量较低(Y=6.83×10^-6~17.65×10^-6,Yb=0.97×10^-6~1.09×10^-6)指示岩石类型为造山带钙碱性花岗岩系列,具I型花岗岩的特点。利用黑云母和角闪石地质温压计估算出岩浆的结晶温度为750~800℃,岩体侵位的压力为0.77×10⁸~0.9×10⁸ Pa,相应的岩体侵位深度在2.55~2.97km,氧逸度为10^-9~10^-12bar,反映了成矿斑岩体形成于高温、高氧逸度的环境,岩浆侵位具浅成-超浅成侵位的特点。结合本区岩石地球化学、矿物学及同位素年代学的研究,推测普朗成矿斑岩体深部仍存在类似的斑岩型Cu(Au)矿化,具有良好的找矿前景。     

安徽宣城荞麦山矿床成矿岩体及其暗色包体成因与成矿意义:锆石U-Pb年代学、地球化学、Sr-Nd-Hf-O同位素制约

宣城矿集区是长江中下游成矿带内新提出的矿集区,近年来取得了重大的找矿突破,尤其是大型斑岩型铜金矿的发现使宣城矿集区逐渐成为研究热点。宣城矿集区一系列的斑岩-矽卡岩矿床均与早白垩世侵入体密切相关。荞麦山铜钨矿床是区内典型的矽卡岩矿床,矿床形成与花岗闪长斑岩密切相关,且花岗闪长斑岩发育较多的暗色包体。确定暗色包体的成因有助于深入理解含矿岩体的岩浆演化过程及成矿意义。本次工作以荞麦山矿床花岗闪长斑岩和暗色包体作为研究对象进行U-Pb同位素年代学、岩石及矿物地球化学、全岩Sr-Nd、锆石Hf-O同位素地球化学分析,探讨暗色包体及成矿岩体的源区、岩浆演化过程及其对成矿的意义。暗色包体的形成时代为141Ma（MSWD=0.8）,（⁸⁷Sr/⁸⁶Sr）_i值为0.7059~0.7069,ε_Nd（t）值为-6.0~-9.2,ε_Hf（t）值为-12.7~-5.8,δ¹⁸O值为5.8‰~7.7‰;寄主岩石形成时代为140Ma（MSWD=0.3）,（⁸⁷Sr/⁸⁶Sr）_i值为0.7061~0.7064,ε_Nd（t）值为-8.7~-7.7,ε_Hf（t）值为-12.1~-8.1,δ¹⁸O值为5.6‰~7.4‰。此外,暗色包体与寄主岩石主要氧化物含量与SiO₂含量呈线性负相关趋势、微量元素特征相似和寄主岩石斜长石斑晶的不平衡结构及捕掳晶的发现指示荞麦山暗色包体为岩浆混合成因,花岗闪长斑岩为起源于富集地幔的岩浆与壳源岩浆混合成的母岩浆侵位而来,同时幔源岩浆和壳源岩浆的混合也分别提供了成矿金属元素铜和钨,最终形成了铜钨共生的荞麦山矿床。     

新疆色尔特能地区超镁铁岩岩石地球化学特征及构造环境分析

通过对出露在康古尔韧性剪切带西段的色尔特能超镁铁岩的野外地质调查和岩石学、岩石地球化学方面的分析研究工作,结果显示：色尔特能超镁铁岩发生了强烈蛇纹石化,基本蚀变成蛇纹岩;岩石主量元素具高Mg （w（MgO）=36.15%~37.96%）、高Cr （w（Cr₂O₃）=0.32%~0.36%）、高Ni （w（NiO）=0.17%~0.21%）、低Si （w（SiO₂）=40.50%~41.92%）、贫Al （w（Al₂O₃）=1.19%~1.77%）、低Fe （w（TFeO）=6.98%~7.87%）特征,Mg^#值为94.71~97.73,m/f值为8.03~9.42,属于典型镁质超镁铁岩,推测原岩为斜方辉石橄榄岩;稀土元素总量w（ΣREE）=1.44×10^-6~2.92×10^-6,配分模式为轻稀土微弱富集近平坦型,w（La）_N/w（Yb）_N=3.09~5.49,具一定程度的负Eu异常（δEu=0.48~1.09）和负Ce异常（δCe=0.53~0.60）;微量元素富集Ba、U、Ta,亏损Nb、Ti。色尔特能超镁铁岩属变质橄榄岩,是SSZ型蛇绿岩的底部组成单元,由原始地幔经2%~10%部分熔融形成的亏损地幔岩,其形成于俯冲带环境中的洋内弧后盆地。     

南天山拜城县波孜果尔A型花岗岩类锆石U-Pb定年及其Lu-Hf同位素组成

新疆拜城县波孜果尔A型花岗岩类岩体位于塔里木地台北缘及邻区的近东西向碱性侵入岩带上,主要岩石类型为霓石钠闪石英碱长正长岩、霓石钠闪碱长花岗岩、黑云母碱长正长岩。全岩SiO₂=68.97%~74.14%,Na₂O+K₂O=9.67%~11.19%,Al₂O₃=13.72%~15.26%,Fe₂O₃=0.18%~1.41%,FeO=0.91%~1.51%,CaO=0.35%~0.63%。稀土元素总量较高,ΣREE=298×10^-6~1286×10^-6,平均706×10^-6,轻稀土富集,重稀土亏损,强烈的Eu负异常,呈“右倾海鸥型”的稀土元素配分模式。富Nb、Ta、Zr、Hf等高场强元素,亏损Ba、K、Sr等大离子亲石元素,Zr+Nb+Ce+Y=936×10^-6~3684×10^-6,平均1813×10^-6。为A1型花岗岩。岩体形成于早二叠纪。锆石LA-ICP-MS U-Pb年龄为287.7~291.6Ma,平均289.8Ma,岩体形成后,在279.1~282Ma左右经历了后期热液流体的改造。锆石ε_Hf（t）值为-6.3~9.0,两阶段模式年龄（t_DM2）跨越古元古代晚期-新元古代中期,主要集中在中元古代。岩浆平均温度832~839℃,形成于非造山的板内构造环境,且具高温、无水、低氧逸度的成岩特点。该岩体具有壳幔混源的特点。     

柴北缘东段奥陶纪埃达克岩-富Nb玄武岩:对大陆深俯冲之前大洋俯冲及地壳增生的启示

在柴北缘东段识别出早古生代埃达克岩-富Nb玄武岩的火山岩组合。埃达克岩富Na₂O、贫K₂O,K₂O/Na₂O比值介于0.14~0.43之间;高Sr（614×10^-6~1043×10^-6）,但亏损Y（3.26×10^-6~14.1×10^-6）和Yb（0.33×10^-6~1.46×10^-6）,具有高的Sr/Y比值（44~282）;富集Sr、Ba等大离子亲石元素,亏损Nb、Ta、Ti等高场强元素及Cr、Ni、Co、V等相容元素。富Nb玄武岩富Na₂O、贫K₂O、高TiO₂,其Nb含量较高,介于16.9×10^-6~17.9×10^-6之间,具有高的Nb/Ta、Nb/U、（Nb/La）_N比值,同时富集高场强元素。埃达克岩锆石U-Pb定年得到453±4Ma和457±4Ma的结晶年龄。锆石ε_Hf（t）范围较大,介于3.40~13.23之间,对应的二阶段模式年龄t_DM2介于1059~566Ma之间,显示以新生物质为主的特征。综合研究表明柴北缘东段埃达克岩可能为岛弧环境下俯冲的南祁连大洋板片部分熔融的产物。板片来源的埃达克质熔体交代或与上覆地幔楔橄榄岩反应,导致被交代的地幔橄榄岩部分熔融而形成富Nb玄武质岩浆。柴北缘东段埃达克岩-富Nb玄武岩火山岩组合的厘定表明南祁连洋可能直到~455Ma之前并未完全闭合,同时表明俯冲大洋板片的部分熔融可能是柴北缘早古生代地壳增生的一种重要方式。     

北大巴山高桥地区镁铁质岩单斜辉石矿物化学特征及其指示意义

在北大巴山高桥地区广泛出露一套镁铁质岩,岩石类型为辉绿岩、辉长辉绿岩、辉绿玢岩和辉石闪长岩等。主要组成矿物为单斜辉石、斜长石、角闪石和铁钛氧化物。本文利用电子探针对单斜辉石进行了详细研究,表明该区所有单斜辉石均属于普通辉石,从辉绿玢岩和辉长辉绿岩到辉石闪长岩,单斜辉石具有从富镁向富铁演化的趋势。单斜辉石内部四面体位置的Al含量为0.02～0.20,Al^Ⅳ/Al^Tot=85%～100%,指示其形成于不饱和的碱性玄武质岩浆中,与单斜辉石碱性判别图解和岩石地化特征反映的碱性岩系列相一致。单斜辉石的平衡温度为1132～1164℃,压力为0.71×10²～9.30×10²MPa,显示明显的深源特征。Al对Si的替代所导致的电荷不平衡主要由Fe³⁺来补偿,Ti大多形成钛辉石,Al^Ⅵ进入八面体形成契尔马克分子Ca（Mg,Al^Ⅵ）,Ca²⁺和Na⁺的类质同像置换使得辉石具有较高Ca含量和较低的Na₂O含量。综合岩体地质产状以及单斜辉石对构造环境的指示意义,认为高桥岩体形成于与俯冲相关的弧后盆地环境,为弧后拉张作用的产物。     

西准噶尔巴音达拉地区卡拉岗组火山岩锆石U-Pb年代学、地球化学及其地质意义

西准噶尔巴音达拉地区发育一套酸性火山岩,被称为卡拉岗组,岩石组合以流纹岩、英安岩、流纹质熔结凝灰岩等酸性火山岩为主。本文对卡拉岗组火山岩进行高精度锆石LA-ICP-MS U-Pb测年,获得英安岩和流纹岩的加权平均²⁰⁶Pb/²³⁸U年龄分别为（294.4±1.3）Ma（n=9,MSWD=0.8）和（298.4±2.5）Ma（n=9,MSWD=3.4）,其形成于早二叠世。岩石地球化学特征表明,卡拉岗组火山岩岩具有高硅（66.69%~75.21%）,富碱（Na₂O+K₂O：6.98%~8.35%）,低MgO（0.18%~1.32%）,贫钙（0.24%~2.49%）的特征,均属过铝质（A/CNK：1.14~1.33）及高钾钙碱性系列。微量元素数据显示,稀土总量为∑REE为83.82×10^-6~197.61×10^-6,（La/Yb）_N=3.15~12.50,轻、重稀土元素分馏比较明显,轻稀土元素（LREE）较为富集,重稀土元素分布相对平坦,球粒陨石标准化配分模式为右倾型。微量元素富集大离子亲石元素（LILE）Rb、Th、U、K,并亏损高场强元素（HFSE）_Nb、Ta、P、Ti。综合最新区域资料及本文研究成果,文章认为研究区早二叠世卡拉岗组火山岩岩浆来源于壳源物质不同程度的部分熔融,残留相中有少量斜长石和角闪石,为后碰撞伸展阶段的产物。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an     

PROSPECTING EXPLORATION

正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of