黄连山自然保护区的土壤及其地理分布规律

本文根据野外调查，土样室内理化分析及对前人工作成果的系统分析结果表明，黄连山自然保护区的土壤及其地理分布规律是；海拔800m以下为砖红壤；海拔800－1100m为砖红壤性红壤；海拔1100—1600m为山地红壤；海拔1600—1900m为山地黄壤；海拔1900m以上为山地黄棕壤。     

Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance

Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite-andesines; and in high-A1 basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite-anorthites.∑REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondritenormalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area.     

甘孜－理塘蛇绿混杂岩带特征及其构造意义

本文系统总结了甘孜－理塘蛇绿混杂岩带的地质学、岩石学和地球化学特征。该蛇绿岩由变质橄榄岩、堆积岩、席状岩墙、枕状玄武岩与块状玄武岩和放射虫硅质岩组成。岩石地球化学特征表明，蛇绿岩形成于洋脊扩张环境。该蛇绿混杂岩带是义敦碰撞造山带大地构造相中的弧前混杂带相。     

Two Periods of Skarn Mineralization in the Baizhangyan W–Mo Deposit,Southern Anhui Province,Southeast China: Evidence from Zircon U–Pb and Molybdenite Re–Os and Sulfur Isotope Data

The recently discovered Baizhangyan skarn‐porphyry type W–Mo deposit in southern Anhui Province in SE China occurs near the Middle–Lower Yangtze Valley polymetallic metallogenic belt. The deposit is closely temporally‐spatially associated with the Mesozoic Qingyang granitic complex composed of g ranodiorite, monzonitic g ranite, and alkaline g ranite. Orebodies of the deposit occur as horizons, veins, and lenses within the limestones of Sinian Lantian Formation contacting with buried fine‐grained granite, and diorite dykes. There are two types of W mineralization: major skarn W–Mo mineralization and minor granite‐hosted disseminated Mo mineralization. Among skarn mineralization, mineral assemblages and cross‐cutting relationships within both skarn ores and intrusions reveal two distinct periods of mineralization, i.e. the first W–Au period related to the intrusion of diorite dykes, and the subsequent W–Mo period related to the intrusion of the fine‐grained granite. In this paper, we report new zircon U–Pb and molybdenite Re–Os ages with the aim of constraining the relationships among the monzonitic granite, fine‐grained granite, diorite dykes, and W mineralization. Zircons of the monzonitic granite, the fine‐grained granite, and diorite dykes yield weighted mean U–Pb ages of 129.0 ± 1.2 Ma, 135.34 ± 0.92 Ma and 145.3 ± 1.7 Ma, respectively. Ten molybdenite Re–Os age determinations yield an isochron age of 136.9 ± 4.5 Ma and a weighted mean age of 135.0 ± 1.2 Ma. The molybdenites have δ³⁴S values of 3.6‰–6.6‰ and their Re contents ranging from 7.23 ppm to 15.23 ppm. A second group of two molybdenite samples yield ages of 143.8 ± 2.1 and 146.3 ± 2.0 Ma, containing Re concentrations of 50.5–50.9 ppm, and with δ³⁴S values of 1.6‰–4.8‰. The molybdenites from these two distinct groups of samples contain moderate concentrations of Re (7.23–50.48 ppm), suggesting that metals within the deposit have a mixed crust–mantle provenance. Field observation and new age and isotope data obtained in this study indicate that the first diorite dyke‐related skarn W–Au mineralization took place in the Early Cretaceous peaking at 143.0–146.3 Ma, and was associated with a mixed crust–mantle system. The second fine‐grained granite‐related skarn W–Mo mineralization took place a little later at 135.0–136.9 Ma, and was crust‐dominated. The fine‐grained granite was not formed by fractionation of the Qingyang monzonitic granite. This finding suggests that the first period of skarn W–Au mineralization in the Baizhangyan deposit resulted from interaction between basaltic magmas derived from the upper lithospheric mantle and crustal material at 143.0–146.3 and the subsequent period of W–Mo mineralization derived from the crust at 135.0–136.9 Ma.     

层序地层学在区域地质调查中的应用

在四川北部广元地区1：5万区域地质调查填图工作中，应用层序地层理论和方法，对测区古生代一中生代海相沉积地层进行了详细划分，利用层序地层对岩石地层单位界线进行了优化，从而提高了测区地层划分对比的精度和预测地质体的能力，使岩石地层单位的划分更为合理。建立了测区岩石地层单位，并论述了层序地层与岩石地层的相关性，提出了层序地层在沉积岩区1：5万区调地质图面的表达方式。     

扬子克拉通东南缘新元古代陆缘弧型TTG的厘定及其构造意义

在扬子克拉通东南缘的江山-绍兴结合带沿线多处出露新元古代深成杂岩,以往被认为是沿扬子克拉通和华夏地块碰撞缝合带侵入的板内型深成岩类。本文选择其中的浙江金华罗店中酸性深成杂岩进行了系统的岩石学、年代学和地球化学研究,提出它们属TTG岩石组合,包括英云闪长岩-奥长花岗岩-花岗闪长岩组合(T1T2G1)和二长花岗岩-花岗岩组合(G2QM)两类,普遍以明显富集Rb、Ba、K、Pb等大离子亲石元素而强烈亏损Nb、Ta、Ti、P等高场强元素为特征,δCe为弱负异常或无异常,属典型的弧岩浆岩类。T1T2G1组合富钠贫钾,εNd(t)值=+2.6~+9.4,Mg#值为41.5~63.1,推断由玄武质俯冲板片脱水部分熔融而成,并受到地幔楔橄榄岩熔体的混染。G2QM组合与T1T2G1组合地球化学特征类似,但又明显富K2O(2.75%~5.08%)、LILE和LREE,低Mg#值(27.2~52.31)和εNd(t)值(+1.7~+2.0),应是T1T2G1源区继续部分熔融的产物,可能未受到明显的地幔楔橄榄岩混染。测得花岗闪长岩(G1)锆石SHRIMP U-Pb年龄为841±10Ma,奥长花岗岩(T2)锆石LA-ICPMS U-Pb年龄为793±13Ma,前人报道之花岗岩(G2)年龄为832±44Ma,结合上述地球化学特征,说明T1T2G1和G2QM组合是由新元古代古华南洋向扬子东南缘持续俯冲形成的。综合区域地质资料及前人研究结果,提出金华罗店与诸暨璜山、绍兴平水等地的深成杂岩共同构成了扬子克拉通东南缘一条长达200km的青白口纪(930~793Ma)陆缘弧型深成杂岩带,反映迟至793Ma前仍存在强烈的洋壳俯冲,扬子克拉通尚未与华夏地块发生碰撞拼合,且T1T2G1-G2QM组合的出现指示洋壳俯冲正处于早-中期阶段。     

浙东南英安质火山岩早侏罗世锆石SHRIMP年龄的首获及其地质意义

浙江中生代晚期火山岩极为发育,而有无中生代早期火山岩,则向无定论。本文在确认浙东南松阳毛弄煤矿一带煤系沉积下部火山岩属中生界毛弄组的基础上,测得其SHRIMP锆石U-Pb年龄为180±4Ma,首次证明浙江存在早一中侏罗世火山岩,同时表明浙东南尚没有确切的中侏罗世晚期至晚侏罗世火山岩活动记录,而且也缺失晚侏罗世和大部分中侏罗世地层。     

西太平洋南段新生代构造单元划分、地层特征及其对喜马拉雅造山运动的指示

系统梳理西太平洋南段（包括华南、日本、菲律宾及东印度尼西亚）部分地区的新生代构造-地层特征,并以区域性角度不整合为主要依据,对喜马拉雅运动期次、时代及其构造背景进行探讨。研究区受白垩纪末期晚燕山运动的影响,古新统乃至下始新统大都缺失,新生界高角度不整合于前新生界之上。根据不同构造单元内地层沉积-火山类型及接触关系对比,研究区新生界可分为3个构造层,即始新统—渐新统、中新统或上渐新统—中新统及上新统以上。上述3个构造层之间为2个穿时的区域性角度不整合分隔,分别对应早喜马拉雅造山运动（33~20 Ma）及晚喜马拉雅造山运动（5.3~2.6 Ma）界面,并以前者最强烈。区域2次构造运动均与岛弧或裂离微地块向欧亚板块边缘的碰撞拼贴有关,指示西太平洋南段喜马拉雅运动是发生于大陆边缘的增生造山过程,受控于太平洋板块和印度洋-澳大利亚板块运动方向与速率变化。在2次构造事件期间,始新世和中新世弧后的强烈伸展,导致华南大陆边缘古老山系的夷平及边缘海的产生,并最终形成现今的地质及地理格局。     

香港世界地质公园晚侏罗世荔枝庄组岩石组合及其成岩地质过程解析

中国东南大陆晚侏罗世地层普遍缺失,仅零星见于个别地区,香港新界东北的荔枝庄组即为其一。荔枝庄组出露于香港世界地质公园沉积岩园区的荔枝庄地区,自下往上由火山岩—沉积岩—火山岩组合而成,沉积岩中发育大型包卷层理和滑塌构造等典型沉积构造,是香港地区最具代表性的晚侏罗世火山—沉积岩系。通过实测地层剖面研究,确定其成岩过程大体上可划分为早期普林尼式火山爆发、中期破火山口湖相沉积和晚期普林尼式火山爆发三个阶段,以湖相沉积作用为主、火山喷发作用为辅;受晚期火山岩浆活动的影响,沉积岩层普遍发生硅化或炭化。荔枝庄组独特的岩石组合与形成的古地理环境,为探讨中国东南大陆中生代火山活动—沉积作用方式与成岩过程,提供了难得的研究实例。     

渤海南部现代沉积特征

渤海南部现代沉积属陆源碎屑沉积，长石含量平均４５．３％，石英２５．９％，可分为六个沉积区，其沉积物类型、矿物组成、沉积速率和风化程度等差异明显。