福建安村矿区寻找隐爆角砾岩矿床的探讨

安村金矿区处于华南褶皱系闽东断拗带的周宁-华安断隆带中段。矿体成矿作用与断裂构造密切相关,矿体受北东、北西断裂带控制;围岩蚀变以硅化、绢英岩化、黄铁矿化最为重要。文章阐述了区域成矿地质背景、西乾金铜矿矿床地质及构造特征和成矿规律,分析了在安村金矿区寻找隐爆角砾岩矿床的可能性,对进一步寻找隐爆角砾岩型矿床方向进行探讨。     

云南某金矿床地质特征及成因分析

该金矿产于哀牢山构造带南段,矿床的形成与哀牢山的构造岩浆活动密切相关,本文通过对该矿床成矿地质背景、矿体特征、矿石特征、找矿标志进行分析研究,判断该矿床为一中低温热液型金矿,矿体多受断层破碎带或层间破碎带控制,通过该矿床成因研究,以期为后续勘查工作提供一定指导。     

黑龙江省伊春市晨明东山金多金属矿地质特征及找矿前景分析

阐述了晨明东山金多金属矿的成矿条件、矿体地质特征,总结了成矿规律。其中金矿与构造关系极为密切,钼矿(化)与蚀变作用发生在区域性大断裂构造之后,初步确定该矿床的成因类型为受构造控制与剪切带有关的矿床。从矿床的成矿规律及控矿构造特征分析,与糜棱岩化二长花岗岩及脉岩有关,深部在脉岩厚度变大的部位有可能找到规模较大的矿体,矿体产状较为稳定,向深部具有一定的延深,说明矿体深部具有较好的找矿前景。     

四川壤塘县扎阔金矿床地质特征及矿床成因

扎阔金矿床产于燕山期中酸性侵入体外接触带--晚三叠世侏倭组碎屑岩中,赋存于NE向韧脆性断裂构造带内,矿体呈脉状.从矿床地质特征、成矿地质条件和矿床地球化学等方面对该矿床进行了分析,指出晚三叠世侏倭组碎屑岩地层为金矿之矿源层,燕山期中酸性侵入体岩浆作用为金矿的形成提供热源,构造作用对含金热液的流动与迁移提供通道.金矿化与硅化、黄铁矿化、褐铁矿化关系密切.其矿床成因为热液一构造蚀变岩型金矿床.     

陕西省华县任家滩金矿地质特征及成因浅析

任家滩金矿位于陕西省华县金堆镇,大地构造位置位于华北地台南缘豫西断隆金堆城坳陷区,在成矿带区划上,位于信阳-栾川-卢氏-金堆城多金属成矿带中。金矿体受区内青岗坪大断裂的次级构造控制,成矿与构造关系密切,矿床类型为构造蚀变岩型金矿。本文在分析区内已有勘查成果的基础上,对区内金矿地质特征、矿床成因进行了分析,对于区内进一步开展金矿找矿勘查工作有一定的参考价值。     

陕西省华县任家滩金矿地质特征及成因浅析

任家滩金矿位于陕西省华县金堆镇,大地构造位置位于华北地台南缘豫西断隆金堆城坳陷区,在成矿带区划上,位于信阳-栾川-卢氏-金堆城多金属成矿带中。金矿体受区内青岗坪大断裂的次级构造控制,成矿与构造关系密切,矿床类型为构造蚀变岩型金矿。本文在分析区内已有勘查成果的基础上,对区内金矿地质特征、矿床成因进行了分析,对于区内进一步开展金矿找矿勘查工作有一定的参考价值。     

甘肃北山营毛沱一带白石滩金矿地质特征及找矿前景浅析

白石滩金矿位于甘肃省营毛沱地区,是近年来新发现的金矿,其矿体赋存于罗雅楚山组砂岩内,主要受EW向次级断裂控制。围岩蚀变以绢云母化、碳酸盐化、硅化和黄铁矿化为主,金的富集与成矿主要受构造和岩体的控制。根据金矿化体产出位置、形态、控矿因素及矿床地质特征,初步判断该矿为构造热液蚀变岩型金矿。通过分析区域地质背景及矿床地质特征,探讨了矿床成因。矿区物化探资料显示,矿区深部及外围具有良好的找矿潜力。该矿床的发现,对找寻区域上同类型矿床具有重要的指示意义和现实意义。     

青海省那尔扎金矿床地质特征及控矿因素

那尔扎金矿床位于东昆仑成矿带东段,矿区内已发现5条金矿化带,共圈定9条金矿体。通过分析成矿地质背景、矿区及矿床地质特征,进而探讨了控矿因素。分析表明:矿体主要赋存在上二叠统格曲组中,围岩蚀变主要有绢云母化、硅化、黄铁矿化、碳酸盐化、褐铁矿化、高岭土化、绿泥石化,其中硅化、黄铁矿化、褐铁矿化与成矿关系密切;断裂构造是主要控矿因素,矿化带和矿体主要受北西西向断裂构造控制。     

山东招远金岭金矿埠上矿区矿体空间定位机制研究

通过对金岭金矿矿区和矿床地质特征的系统分析,在详细研究了金岭金矿埠上矿区控矿断裂面形态、产状的空间变化和矿体空间展布特征的基础上,结合金岭金矿控矿构造面等值线图、工业矿体展布与控矿构造面夹角关系等值线图、勘探线剖面图和应力分析示意图等图件以及成矿后构造的改造与影响,并相互比较,综合研究,揭示金矿体是在断裂构造走向上偏北、倾向上倾角变陡的局部引张部位富集成矿的规律,总结并建立了金矿体受控矿构造左旋正断控制和分段富集的空间定位模型,进而为矿区及其外围开展矿体定位预测和矿产开发提供有益的信息.     

四川若尔盖阿西金矿床地质特征及成因探讨

通过对阿西金矿床地质特征、成矿条件和矿床成因的研究,认为阿西金矿床产于中三叠统扎尕山组第三、四段的碎屑岩和碳酸盐岩中,赋存于闪长岩体的内、外接触带,受NW向断裂带控制。金矿(化)带的形成与闪长岩体有密切关系,产于岩体外接触带围岩构造破碎带中的金矿体是阿西金矿床最重要的矿体。矿体形态为脉状、似层状及透镜状,矿体厚度及品位变化不大,矿化相对均匀。金矿化与硅化、碳酸盐化、黄铜矿化、黄铁矿化关系密切。中酸性岩浆活动与断裂构造是矿床形成的先决条件。该矿床成因为岩浆及(期后)热液改造型矿床。     

胶东大磨曲家金矿控矿断裂及成矿规律

招平断裂带是胶东地区的重要控矿构造, 大磨曲家金矿是赋存于该断裂带北段的大型破碎带蚀变岩型金矿床。区内302号破碎蚀变带与上下盘次级断裂共同组成大磨曲家金矿控矿断裂系统, 并控制了金矿体的产出。矿区存在构造—蚀变—矿化的水平分带性。总结了矿床矿化富集规律, 进行了深部找矿预测。     

黑龙江和平林场环形构造特征及对金矿控制作用

根据和平林场环形构造产出的地质背景和遥感影像特征,探讨环形构造与线性构造的关系及其成因,指出环形构造及与之相关的断裂、热液蚀变、化探异常与金成矿的关系密切,圈出了10 处找矿靶区。     

鲁西关山头-车往峪地区隐爆角砾岩群地质特征及成矿前景

通过对关山头—车往峪地区角砾岩群的分布特征、岩石特征、矿化蚀变及构造控制因素的分析, 指出该角砾岩群由隐爆作用形成。隐爆角砾岩群出露区分布有磁异常及Au、Ag、Cu、Pb、Zn等元素化探异常, 基岩显示出较高的As、Sb元素化探异常。通过分析认为, 关山头—车往峪地区成矿前景较好, 深部可能存在隐伏矿体。     

江西金山金矿田门前山金矿地质特征及找矿方向

门前山金矿床位于江西省金山超大型金矿田北西缘,是矿田内继金山、西蒋、石坞、朱林西等后发现的又一处具有影响的金矿床,找矿成果丰富了金山金矿田深边部找矿理论.矿区内金矿找矿,证实了矿田内金山-朱林、西蒋-石碑等主要剪切带及金矿体倾向上的深部延伸,剪切带的构造岩分带、蚀变分带明显,具有典型的＂超糜棱岩、糜棱岩带-石英、黄铁矿、铁白石化带-金矿化（体）带＂等构造岩-蚀变-金矿化三位一体的成矿特征.矿床成因为受韧性剪切带控制的变质热液型金矿床,具有＂火山沉积-区域变质-动力变质-韧性剪切带控矿容矿-改造叠加＂的综合成矿模式.文章论述了门前山金矿床的成矿地质背景、矿石类型及组构、矿体特征、围岩蚀变特征及控矿韧性剪切带等地质特征,进而提出了进一步找矿的方向.     

Prefrontal contributions to delayed spatial and object alternation: A positron emission tomography study.

Delayed alternation tasks are frequently used as probes of frontal lobe functioning. To clarify the neural substrates of delayed alternation performance in humans, the authors measured regional cerebral blood flow with H?1?O positron emission tomography in healthy subjects as they performed delayed spatial and object alternation. Consistent with the monkey lesion literature, increased dorsolateral prefrontal activity emerged during delayed spatial alternation but not delayed object alternation, whereas orbitofrontal activations emerged in both alternation tasks. The possible cognitive processes contributing to the orbitofrontal and dorsolateral prefrontal involvement in delayed alternation are discussed. Additional activations localized to several nonfrontal. regions suggest caution in interpreting alternation deficits in patients as strictly reflecting frontal lobe impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

陕西铧厂沟金矿床地质特征及成矿规律

铧厂沟金矿床位于秦岭褶皱系南部,北距康县—略阳—勉县深大断裂4 km。金矿化严格受地层、岩性及韧性剪切带控制,主要控矿层位为蚀变细碧岩及灰岩与粉砂质千枚岩之间的过渡部位,控矿构造多为压扭性断裂。金矿体呈脉状和透镜状产出,矿化带类型以蚀变细碧岩型及蚀变碳酸盐岩型为主,黄铁矿是矿石中最主要的载金矿物。矿石中金的赋存状态主要为包裹金和裂隙金,粒间金次之,围岩蚀变主要有黄铁矿化、硅化、碳酸盐化、钠长石化和绢云母化等。黄铁矿热电系数和原生晕地球化学研究显示,本区金矿体向深部有一定的延伸,应重点加强细碧岩型矿带和砂岩矿带的地质找矿与探矿工作。     

Recovery of delayed alternation in rats after lesions in medial frontal cortex and septum.

Two experiments using contingently reinforced T-maze alternation with 48 male Long-Evans and hooded rats found that (a) normal Ss, after achieving high accuracy in alternation with brief (0 sec) intertrial intervals (ITIs), dropped to chance levels with longer ITIs (90 sec) but reacquired effective alternation with additional practice; (b) small lesions in mediodorsal pregenual cortex had no effect on postoperative retention of alternation at either short or long ITIs; (c) however, small lesions in posterodorsal septum temporarily disrupted alternation at brief ITIs, whereas at long ITIs Ss chose randomly and never recovered; and (d) large lesions in medial frontal cortex disrupted retention of alternation at brief ITIs of 10 sec but significant recovery did occur with additional experience. Implications regarding task difficulty and locus of lesion for recovery of function are discussed. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of effects of small lesions in posterodorsal septum on spontaneous and rerun correction (contingently reinforced) alternation in rats.

Compared characteristics of T-maze alternation behavior by giving 11 hooded rats 7 sessions under conditions of "rerun correction" (contingent reinforcement for alternation) and another 11 Ss the same number of sessions with noncontingent reinforcements (i.e., entering either goal arm of the –T maze was reinforced). Both groups alternated significantly above chance, and the difference in medians between groups was small but significant. However, Ss given rerun correction training quickly came against the "ceiling" of 100% alternation, and individual differences were small. Scores of Ss run under conditions of "spontaneous" alternation were more variable, both within and between Ss. In a 2nd part of the study, 6 Ss in each group received small electrolytic lesions in posterodorsal septum. There were 5 operated-control Ss from each group. After 2-wk recovery all Ss were again given 7 sessions in the –T maze. Under rerun correction procedure, controls retained near-perfect alternation scores. Most Ss with lesions dropped to chance levels but recovered to control level over the sessions. Ss tested under spontaneous alternation conditions behaved quite differently. Controls continued to alternate significantly, but Ss with lesions alternated significantly less and did not recover. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous alternation behavior.

Research concerned with spontaneous alternation behavior in rats is examined and related to learning theory. It is concluded that alternation behavior can no longer be adequately interpreted in terms of Hull's concept of reactive inhibition. The notion of stimulus satiation as an explanation of alternation behavior has received general support from the research literature, but some data seem to require a more general theoretical explanation. Motivational concepts such as curiosity are suggested. 47 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential ontogeny of working memory and reference memory in the rat.

Examined the ability of 15-, 21-, and 27-day-old rats to perform 2 spatial working memory problems (delayed alternation and discrete-trials delayed alternation) and a reference memory problem (position habit) in a T-maze. In the delayed alternation problem, each S was presented with a series of free-choice trials and was rewarded for regularly alternating responses to the left and right arms of the T-maze. In the discrete-trials delayed alternation problem, each S was forced to one maze arm and rewarded (forced run) and was then placed back into the start box and given a choice of arms (choice run). The direction of forced runs followed an irregular, counterbalanced series, and Ss were rewarded for choosing the alternate maze arm on choice runs. In the position habit problem, Ss were rewarded for consistently choosing 1 of the 2 arms of the T-maze. At all ages, rat pups learned to perform the delayed alternation and position habit problems. Only 21- and 27-day-old rats were able to learn the discrete-trials delayed alternation problem. Results of these experiments show that reference memory capacity is present by at least 15 days of age in the rat and does not develop further at later ages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)