浅析冈底斯带雄村式斑岩型铜金矿找矿地质标志及找矿方向

西藏雄村斑岩型铜金矿是冈底斯成矿带发现的重要的斑岩型铜金矿床,该矿区的成矿期次包括中侏罗世早、晚两期,矿区的成矿构造背景为与新特提斯洋洋内俯冲作用相关的岛弧环境。该区成矿时代比冈底斯传统意义上第三纪与印度-亚洲大陆碰撞过程中有关矿床成矿时代早100Ma左右,这为冈底斯带找矿指明了新的方向。本文将从大地构造演化、构造、岩浆岩、地层等四个方面对雄村式铜金矿找矿地质标志及下一步找矿方向进行分析。     

广西龙头山金矿床赋矿岩石地球化学特征

广西龙头山金矿床产于晚中生代残存的火山颈机构中。通过对金矿床火山-次火山岩的类型、空间展布及其岩石学和岩石化学等特征分析,结果表明：SiO2含量变化在62.77%～75.24%之间,La/Ce与Rb/Ti比值基本不变,稀土配分曲线为向右倾斜的富轻稀土型,同时铕亏损强烈。研究认为本区岩浆岩均属亚碱性系列英安流纹斑岩类岩石,为一套陆相中心式火山-次火山喷发-侵入岩系,形成于具有火山弧（碰撞期前）-同碰撞性质的构造环境中,具壳幔混合来源特征。     

青海省板块构造体系及演化

运用板块构造理论, 对青海省内板块构造体系及其发展演化做了初步探讨, 并提出一些新的认识。青海省位于古亚洲和特提斯构造域接合部位。在漫长的地史演化过程中, 大陆裂解和大洋扩张, 大陆板块的飘移与碰撞, 洋壳俯冲与大洋消亡, 地壳隆升与造山, 陆陆碰撞及陆内裂陷等活动频频发生, 形成了极其复杂的构造沉积环境及板块构造体系。     

燕辽成矿带铜钼矿床时代与动力背景关系

燕辽铜钼多金属成矿带是中国华北地台北缘重要的铜钼成矿带。燕辽地区与铜钼矿床有关的岩浆侵入活动主要集中在227 Ma、189.0～169.9 Ma、142.0～126 Ma 3个时期;铜钼矿床成矿时代主要集中于242.6～233.1 Ma、197.0～185.0 Ma、164.3～131.0 Ma 3个时期,铜钼多金属矿床的成矿作用与岩浆活跃期关系比较密切。该区内主要的多金属矿床的成矿动力学背景形成分别是:早期的板块碰撞动力源,中-晚三叠世的华北板块与西伯利亚板块相互碰撞后期的挤压造山作用阶段;中期为侏罗世的鄂霍茨克洋的消减到闭合及后期两大陆块持续碰撞挤压阶段;后期为板块俯冲,深部幔源物质上升,岩石圈减薄等的动力学作用阶段。     

巴颜喀拉构造带二叠-三叠纪岩相特征及构造演化

特提斯洋的形成与演化问题是青藏高原重大基础地质问题之一,通过多年的野外观察、分析测试和综合研究,结合覆盖全区及相邻地区的1:25万区域地质调查资料及其他前人研究成果,尤其是对巴颜喀拉构造带二叠-三叠纪地层、岩相特征及构造古地理环境进行了系统研究,并探讨了其构造演化,以期对提高青藏高原特提斯洋演化历史和潘吉亚大陆形成特征等方面的研究工作有所裨益.巴颜喀拉构造带未出露前二叠纪地层,二叠一新近纪地层均有出露,尤以三叠纪地层广泛出露为其主要特征.其中,二叠-三叠系主要为海相沉积,比较连续,尤以海相三叠系最具特色,著名的巴颜喀拉山群横贯全区,分布广泛,厚度巨大,侏罗-第四系主要为陆相河湖沉积.二叠系黄羊岭群岩性为碎屑岩、碳酸盐岩夹火山岩,自下而上表现为浅海相-深海、半深海相-浅海相沉积演化特征;三叠系主要为巴颜喀拉山群,岩性单调,主要为砂泥质类复理石沉积,局部地区夹钙质及火山物质,沉积环境总体表现为浅海相-深海、半深海相-滨浅海相-陆相沉积演化序列.二叠-三叠纪构造古地理环境表现为拉张裂陷形成洋(海)盆-汇聚、部分碰撞形成残留洋(海)盆、前陆盆地-拉张裂陷形成洋(海)盆-汇聚、部分碰撞形成残留洋(海)盆、前陆盆地-完全碰撞造山,海水退出,进入陆相沉积演化的历史.巴颜喀拉地区是塔里木-中朝陆块与南方大陆(冈瓦纳陆块)之间古特提斯洋域的主洋盆所在地区之一,与其南部龙木错一双湖洋盆共同构成古特提斯洋域的双洋域.     

雪峰山基底隆升带及其邻区印支期陆内构造特征与成因

狭义的华南陆块东部包括扬子地块和华夏地块,而雪峰山陆内构造系统是扬子地块的重要组成部分.通过对雪峰山地区印支期地层角度不整合时空分布规律的分析表明,高角度不整合-微角度不整合-平行不整合-整合的空间分布区域依次由东往西递变浙新.根据褶皱变形分析得出,雪峰山地区在印支期发育了北东东向和北北东向2个轴迹方向的褶皱,后期叠加了南北向弧形逆冲推覆构造.区域构造背景和动力学分析表明,扬子地块内部印支期总体北东向的变形形迹与东西轴向的秦岭-大别造山带和扬子地块南部东西轴向的构造线相垂直其原因是:扬子地块与华夏地块最终陆内收缩变形的时间比扬子与华北沿秦岭-大别造山带的陆间碰撞拼合的时间早,印支早期的先存北北东向构造线在印支晚期由于扬子地块顺时钟旋转变位为北东东向,从而决定了印支早期现今北东东向的构造线,随后的第二幕北北东向构造线的形成是在与早期第一幕变形的应力场相同的同一构造应力场作用下形成的.但是,秦岭-大别造山带近东西向的构造线取决于主动大陆边缘,即总体近东西向的华北陆块南缘边界,其原始方位为总体近东西向.这些复杂边界条件和旋转决定了先形成彼此近于垂直的构造线,然后拼接形成现今构造线垂直的格局.     

东天山印支期岩浆岩与成矿作用研究进展

东天山印支期钼成矿作用广泛而强烈,东戈壁钼矿床、花黑滩钼矿床。古生代板块缝合带周边分布着大多数钼矿,与成因联系密切是造山后钙碱性花岗岩,成矿作用高峰期在235Ma～220Ma。矿石中辉钼矿铼含量表明,成矿物质中有不同程度幔源组份的贡献。造山后伸展背景下,软流圈地幔上涌底侵、岩石圈拆沉,致使下地壳部分熔融,乃成岩-成矿重要动力学条件,也为成矿作用带来丰富热能、流体及成矿物质。成矿物质主要来自古生代增生作用形成的不成熟大陆壳。已有成矿年龄显示了印支期成矿事件在东天山地区非常显著,发生于大陆碰撞造山体制区域性深大断裂是流体上侵入或深部岩浆成矿的有利部位为圈定找矿靶区提供依据。     

新疆阿勒泰市哈腊苏地区铅锌矿区域地质特征及找矿远景

哈腊苏铅锌矿位于阿勒泰市南东西伯利亚板块阿尔泰陆缘活动带克兰古生代火山弧中部的阿勒泰火山的沉积盆地中,为活动大陆边缘陆内裂谷火山盆地,区内出露地层主要为中泥盆统阿勒泰组下亚组、上亚组及第四系。成矿区带属阿尔泰成矿带克兰多金属成矿亚带,是金、铁、铜、铅锌等重要多金属成矿远景区。     

Rodinia超大陆旋回与华南新元古代成锰作用

中—新元古代,华南陆块新元古代南华纪地层中所形成的锰矿床大多集中在700 Ma左右,与Rodinia超大陆全面裂解时期一致。锰矿的成矿作用与晋宁运动后华南陆块大规模裂解事件密切相关,显示构造环境由挤压向拉伸的转变,这正是全球Rodinia超大陆裂解的表现形式。从同位素地质年代学、大地构造、沉积环境方面探讨了该时期的成锰作用,认为其与Rodinia超大陆旋回事件的关系密切。研究区的锰矿探矿工作可以沿Rodinia超大陆裂解时期华南陆块形成的一系列裂陷槽及同沉积盆地开展,为锰矿的找矿工作提供了思路。     

阳山金矿矿化-未矿化岩脉中锆石年代学研究

阳山金矿位于扬子、中朝板块及松潘-甘孜褶皱带所夹持的三角区域内。本文对矿区内矿化-未矿化花岗斑岩脉中锆石进行了LA-ICP-MS U-Pb年龄测定,探讨岩脉与金成矿的关系。结果显示,矿化与未矿化花岗斑岩脉内锆石呈自形柱状,环带韵律结构发育,具岩浆锆石特征。锆石²⁰⁶Pb-²³⁸U协和年龄可分为2组,分别为(727±28)Ma与(212.5±2.6) Ma,其中第1组年龄为捕获新元古代华南板块碧口群锆石;第2组年龄为花岗斑岩结晶年龄,且该期岩浆活动与金成矿作用密切相关。早-中三叠世扬子-秦岭微陆块与华南板块发生碰撞,并逐渐由挤压体系向拉伸构造体系转化,晚三叠世岩石圈发生大面积拆沉,导致秦岭碧口地块发生熔融形成岩浆,最终形成花岗斑岩脉,进一步为金矿的形成奠定基础。     

Insulin resistance, high prevalence of diabetes, and cardiovascular risk in immigrant Asians. Genetic or environmental effect?

OBJECTIVES: To compare the prevalence of diabetes, hyperinsulinaemia, and associated metabolic abnormalities in immigrant Asians, Asians in India, and native white British men. DESIGN: Case control study. SETTING: Wythenshawe Hospital, Manchester, United Kingdom, and Maulana Azad Medical School, New Delhi, India. SUBJECTS: Men with angiographically proved coronary artery disease; 83 British Asians, 87 white men, and 30 Indian Asians with age matched controls. INTERVENTIONS: Fasting lipid concentrations, serum glucose, and total insulin concentrations were measured in the fasting state and one and two hours after a 75 g glucose load by mouth. All subjects had a physical examination by the same observer. RESULTS: Asians in the United Kingdom and in India had a higher prevalence of diabetes and impaired glucose tolerance than the white British men. Patients in all three ethnic groups had higher total insulin concentrations than their controls in the fasting state and after the glucose load. British Asian and Indian Asian patients and controls had higher total insulin concentrations than the white men in the fasting state and after the glucose load. Total insulin concentrations were similar in British and Indian Asians, though fasting concentrations were higher in British Asians than Indian Asians. White men had similar cholesterol, lower triglyceride, and higher high density lipoprotein cholesterol concentrations than Asians in the United Kingdom and in India. British Asian patients had higher cholesterol concentrations and British Asian controls had higher triglyceride concentrations than the Indian Asian groups. Asian patients and controls were more active. British and Indian Asian patients had higher waist to hip ratios than controls. The waist to hip ratio was positively correlated with insulin and triglyceride concentrations and negatively correlated with the high density lipoprotein cholesterol concentration. Fasting insulin and high density lipoprotein concentrations were independent predictors of coronary artery disease in white men, whereas in British Asians the waist to hip ratio was the strongest independent predictor. In Indian Asians the waist to hip ratio and high density lipoprotein concentration were independent predictors of coronary artery disease. CONCLUSIONS: Central obesity in the subgroups of Asians studied showed a close association with hyperinsulinaemia and the risk of coronary artery disease. A predisposition to insulin resistance and its metabolic abnormalities in this group of Asians seems to be genetically determined, environmental changes after migration having only a small additional effect.     

内蒙古洪格尔地区斑岩型矿床成矿作用及矿床特征

中蒙边境洪格尔地区近年来先后发现了多处大中型斑岩型钼多金属矿床,矿床的形成时代大致可以划分为三期:海西期290~300Ma、印支期190~200Ma和燕山期130~135Ma,矿床的形成与古亚洲洋板块碰撞缝合及后期板块的伸展作用有关。矿床普遍具有低电阻率、高极化率的电性特征以及成矿元素异常面积大、浓度高、套和良好、具有明显的浓集分带和浓集中心等地球化学特征。板块的碰撞俯冲及后期的伸展作用所诱发的富碱性岩浆作用及相关流体活动为钼多金属矿床的形成提供了动力和物质来源。     

Effect of doctors' ethnicity and country of qualification on prescribing patterns in single handed general practices: linkage of information collected by questionnaire and from routine data

OBJECTIVES: To test whether Asian general practitioners who qualified in the Indian subcontinent prescribe items more often, more expensive items, and fewer generic drugs than their British trained Asian and non-Asian counterparts. DESIGN: Linkage study using data collected by questionnaire and from routine sources. SETTING: General practices in England. SUBJECTS: 155 single handed general practitioners: 42 Asian doctors qualified in United Kingdom (group 1), 58 white doctors qualified in United Kingdom (group 2), and 55 Asian doctors qualified in Indian subcontinent (group 3). MAIN OUTCOME MEASURES: Prescribing cost (cost per ASTRO-PU), prescribing frequency (number of items per ASTRO-PU), and generic prescribing (percentage of drugs prescribed that are generic). RESULTS: Doctors in group 1 were significantly younger than those in the other groups and had a higher proportion of patients who were from deprived wards. There was no difference between the groups in the proportion of female doctors and total list size. After adjustment for confounding factors, there were no significant differences between the three groups for prescribing cost (16.58 (95% confidence interval 6.39 to 26.77) for group 1, 17.31 (6.92 to 27.69) for group 2, 17.80 (7.22 to 28.38) for group 3, P = 0.55); prescribing frequency (6.58 (4.60 to 8.40), 6.45 (4.70 to 8.30), 7.89 (6.16 to 9.64), P = 0.34); and generic prescribing (44.44 (38.95 to 49.93), 47.41 (42.12 to 52.70), 44.04 (38.75 to 49.33), P = 0.37). CONCLUSIONS: Asian doctors qualified from the Indian subcontinent did not differ from British trained doctors in their prescribing practice. This study refutes the common belief that Asian doctors are high volume and high cost prescribers.     

四川会理大铜厂铜矿床地层控矿规律分析

大铜厂铜矿床为陆相沉积砂砾岩型铜矿床。矿床与盆地内下部含煤建造、中部红色含铜碎屑岩建造和上部白色膏盐建造关系密切。含矿岩系具有向上变细的剖面结构。矿体严格受白垩系地层控制并呈层状似层状产出。含矿岩石以细砾岩为主,铜矿化与沉积物颜色、砾岩中砾石成分亦有着密切关系。     

Hemoglobins Aida (alpha 64 Asp leads to Asn) and D-Los Angeles (beta 121 Glu leads to Gln) in an Asian-Indian family

Hemoglobins D-Los Angeles (beta 121 Gln) and Aida (alpha 64 Asn) were encountered in an Asian Indian, unassociated with any clinical manifestations. These hemoglobins had normal oxygen affinities and were stable to heat and isopropanol. The ratio of alpha chain synthesis to beta chain synthesis was close to unity. The identical change in isoelectric points of the two variants produced an interesting electrophoretic pattern.     

Asian Indians' responses to discrimination: A mixed-method examination of identity, coping, and self-esteem.

The focus on racial injustice in ethnic minority psychology recognizes a need to understand the effects of racism experienced by Asian Indians in the U.S. Utilizing a mixed-method approach with 102 first and second generation Asian Indians, we examined (a) when and why race and ethnicity are salient for Asian Indians, (b) the mediating roles of racial identity and ethnic identity, and (c) the moderating roles of generational status and racial socialization on the relationship between racism related stress, self-esteem and coping. Qualitative analyses revealed distinct and overlapping themes related to race and ethnicity highlighting the relevance of both constructs to participants. Quantitative analyses revealed racial identity to be a significant mediator in the relationship between racism related stress, self-esteem, and coping. Neither generational status nor racial socialization experiences moderated this relationship. Implications of these findings for research and clinical intervention with Asian Indians are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

MR findings of hypoxic damage of the bilateral striate cortices: a case report

The frequency of accessory mental foramina (AMF) was studied in four population groups: 20th century Asian Indians, African Americans and American Whites, and Pre-Columbian Nazca Indians. AMF were found less frequently in the American White and Asian Indian populations than in the other groups (American White, 1.4%; Asian Indian, 1.5%; African American, 5.7% and Nazca, 9.0%). The incidence of AMFs did not differ significantly between right- and left-hand sides. In certain ethnic groups, i.e., African American, AMF may occur more often in males. Additional studies with larger samples are needed to show whether AMFs are more common in males.     

马厂箐斑岩型铜、钼矿辉钼矿Re-Os年龄及地质意义

滇西马厂箐富碱侵入岩体为多期、多阶段岩浆活动叠加侵入的复式岩体,其岩浆活动时限为52～29 Ma,最早岩浆活动始于52Ma,中期岩浆活动为47～42Ma,晚期岩浆活动为37～29Ma。采用ICP-MS法测定宝兴厂斑岩型铜、钼矿中的辉钼矿Re-Os同位素年龄,获得其模式年龄为34.9±0.8～36.0±0.5Ma,加权平均值为35.3±0.7 Ma,指示了马厂箐铜、钼矿床的成矿时限为35～36Ma左右。这种方法获得的年龄与马厂箐复式杂岩体晚期花岗斑岩(29～37 Ma)相吻合,表明成矿作用主要与晚期岩浆侵入活动有关。马厂箐铜、钼多金属矿床存在2种矿体产出形态和矿物组合形式,均属于同期成矿作用的产物,是同期成矿作用在不同空间部位上的不同表现形式,属于同一个成矿系统。金沙江-哀牢山成矿带斑岩型铜、钼矿床是同期成矿作用的产物,成矿时限集中在35～36Ma。     

Dynamic transformation above the A_(e3) in a 0.06%C low carbon steel

A 0.06%C low carbon steel was deformed in torsion over the temperature range 877-917℃in a 2% H₂ - Ar gas atmosphere.Strains of 0.25 -5.0 were applied at strain rates ofε= 0.04 s^-1 andε= 0.4 s^-1 to study the formation of ferrite by dynamic transformation（DT） at temperatures above the A_e3.The critical strain for ferrite formation by DT was aboutε= 0.2 and its volume fraction increased with strain and decreased with temperature above the A_e3.Average ferrite grain sizes of 1.5μm to 5μm were produced,which decreased with strain rate.At the lower strain rate(ε= 0.04 s^-1) reverse transformation（RT） took place during deformation once an incubation time of about 40 s,was exceeded.An increase in strain rate fromε= 0.04 s^-1 toε= 0.4 s^-1 arrested RT during testing at all temperatures as the total test times did not exceed 13 s.The present work shows that DT is favored at higher strain rates by increasing the driving force（i.e.stored energy ） and by suppressing RT.     

Lipoprotein(a) is an independent risk factor for coronary artery disease in NIDDM patients in South India

OBJECTIVE: Asian Indians have been reported to have very high prevalence rates of coronary artery disease (CAD) in the absence of traditional risk factors. Recently, elevated levels of lipoprotein(a) [Lp(a)] have been reported to be associated with premature CAD in migrant Asian Indians. However, there are very little data regarding Lp(a) in CAD patients from the Indian subcontinent and virtually none in individuals with NIDDM. The objective of this study was to assess the role of Lp(a) as a marker for CAD in South Indian NIDDM patients. RESEARCH DESIGN AND METHODS: We estimated serum Lp(a) in 100 control subjects, 100 NIDDM patients without CAD, and 100 NIDDM patients with CAD. Lp(a) values were transformed into natural logarithms. Statistical analysis included Student's t test, one-way analysis of variance, and chi2 test. Multiple logistic regression analysis was used to identify associations with CAD. RESULTS: Lp(a) levels were significantly higher in NIDDM patients with CAD compared with NIDDM patients without CAD and control subjects (geometric mean 24.6, 15.1, and 19.4 mg/dl, respectively, P < 0.05). Results of logistic regression analysis showed that Lp(a), age, and HDL were associated with CAD. In NIDDM patients with CAD, there was no correlation between Lp(a) and serum cholesterol, triglyceride, or HDL cholesterol levels, but there was a weak association with LDL cholesterol and systolic blood pressure. CONCLUSIONS: The data suggests that serum Lp(a) is an independent risk factor for CAD in NIDDM patients in South India.