东天山北麓2000多年以来的森林线与环境变化

依据吉木萨尔县泉子街乡桦树窝子和小西沟两个剖面进行高时间分辨率的孢粉分析，结合剖面岩性特征分析、历史文献记录和碳屑鉴定，揭示了天山北麓最近2000多年以来的环境变化。2000aB．P．以前，该地植被为荒漠草原；2000-1300aB．P．(50a B．C．-650A．D．)，植被为草原植被，其中1750—1400aB．P．(200—550A．D．)，植被为有少量森林的草原植被，当时气候状况较今凉湿，适宜云杉生长，使得云杉林带下移，幅度可达250m左右。当时的年均气温较今低1℃而降水量较高，是新疆历史上一个相对冷湿的环境；约1300—450a B．P．(650—1500A．D．)，植被为荒漠草原；4．50aB．P．年以来，植被为荒漠草原—草原。     

苏北溱潼凹陷戴南组一段次生孔隙形成与分布特征

次生孔隙是戴南组一段（E2d1）砂岩储层的主要孔隙类型，其分布与油气聚集关系密切。本文在沉积、成岩作用研究基础上，探讨了次生孔隙成因机理，指出有机酸的溶解作用是形成戴南组一段次生孔隙的主要原因，并根据有机质成熟生烃和粘土矿物的转变导致的泥岩压实异常特征，进行次生孔隙的横向分布预测，取得了凹陷不同构造带次生孔隙分布与油气聚集规律的新认识。     

Mobility of heavy metals as a function of pH of samples from an overbank sediment profile contaminated by mining activities

Parts of the flood plains north of the Harz Mountains are contaminated with heavy metals, such as Pb, Cu, Zn and Cd derived from mining, which has been carried out in the Harz Mts. since the Middle Ages. It is important to know the mobility of the heavy metals in these overbank sediments in order to estimate the danger to the environment arising from this source. This paper deals with the effect of pH on heavy-metal mobility, using a constant-pH method. The investigations were carried out on an overbank sediment profile near Salzgitter Bad, north of the Harz Mts. The mobility of the heavy metals in the overbank sediment profile is described as a function of pH and depth. Besides the mobile heavy-metal fraction at a certain pH, the buffering capacity of the sediment at this pH must be taken into consideration. The different layers of the overbank sediment profile show distinct differences in buffering capacity and a natural pH harrier could be identified in the upper part of the profile. Therefore, to avoid increasing heavy-metal mobility the natural layering of the overbank sediment profile should not be disturbed. Two different kinds of desorption experiments at constant pH are also discussed, as well as the conversion of the heavy-metal species in the ore minerals into the species in the sediment.     

天山北坡降水对河流水沙情势影响

以天山北坡头屯河流域为例，在对山区不同海拔的降水特征、侵蚀产沙情势以及河流水沙运移特点分析的基础上，详尽就山区降水对河流水沙情势的年际变化、年内变化以及月变化的影响进行了分析研究，并就降水对不同海拔的河流水沙情势的影响强度及相互关系作了探讨．     

辽东湾北部浅海区泥沙输送及其沉积特征

根据实测资料，本文定量分析了辽东湾北部泥沙输送及其分布，并对辽河三角洲沉积区划作了初步讨论。研究表明本区泥沙以纵向搬运为特征。双台子河以西来沙和辽河西水道入海泥沙是区域东部拦门沙体和浅滩发育的主导因素。汛季大潮期，泥沙自西向东运移落淤在河口及毗邻浅水域；小潮期，泥沙除向东扩散外，大部泥沙向海方搬运。调查区可划分六个现代沉积作用区，即潮坪沉积区、辽河水下三角洲细粒沉积区、河口沙洲沉积区、波浪潮流冲蚀沉积区、河口冲积沉积区以及潮汐水道沉积区。     

大别山超高压石榴多硅白云母片岩中钻石U－Pb年龄

大别山超高压石榴多硅白云母片岩中钻石Ｕ－Ｐｂ年龄刘晓春（中国地质科学院地质力学研究所，北京１０００８１）李惠民，左义成（地质矿产部天津地质矿产研究所，天津３００１７０）关键词石榴多硅白云母片岩，Ｕ－Ｐｈ年龄，早元古代表壳岩，印支期超高压变质，大别山高...     

青藏高原北缘新构造运动特征

ＮＥＥ向阿尔金主断裂带的新构造运动以左旋压扭性活动为特征，仅西端发育张性构造，并可划分出两期变形，新构造运动强度在时间上自上新世晚期开始至第四纪断裂活动强度增大，在空间上自ＳＷＷ向ＮＥＥ方向断裂活动强度逐渐减弱；柴达木北缘的新构造运动可划分为两期，其主要构造特征表现为向柴达木盆地逆冲的前进式叠瓦道冲带，柴达木盆地第四纪时的北界相对于第三纪时的北界向南迁移了数十公里；河西走廊盆地的新构造运动主要表现为盆地边缘断裂的逆冲兼走滑，盆地接受新生代沉积、盆地内第三系的轴面南倾的褶皱；ＮＥＥ向阿尔金主断裂带与其南侧的ＮＷＷ向断裂带是在统一构造应力场作用下相互协调、同时活动的两组关系紧密的构造带，两者的共同活动构成了断块运动。     

露头剖面层序中的海平面变化研究

在以往的沉积研究中，常常用露头剖面中的相对水深变化来讨论海平面的变化规律，本文通过对塔里木盆地北部寒武纪反映相对海平面变化的上超点变化曲线与肖尔布拉克地区寒武系露头剖面中相对水深变化曲线的对比研究发现，上超点变化曲线与相对水深变化曲线具有明显的差异，前者在寒武纪呈持续上升趋势，而后者除早期有一快速上升外，总体呈持续下降趋势，这说明相对水深变化虽与海平面变化存在着本质的联系，但单凭露头剖面中相对水深     

Magmatic arc metamorphism: petrology and temperature history of metabasic rocks in the Coastal Cordillera of northern Chile

We investigated the metamorphic cooling history of underplated magmatic rocks at midcrustal depth. Granulites and amphibolites occur within the Jurassic magmatic belt of the Coast Range south of Antofagasta in northern Chile between 23°25' and 24°20' S. The protoliths of the metamorphic rocks are basic intrusions of Early Mesozoic age. They are part of the magmatically formed crust, and the essentially dry magmas were emplaced in an extensional regime. The granulites (clinopyroxene–orthopyroxene–plagioclase) show all stages of fabric development from magmatic to granoblastic fabrics. Pyroxene compositions were reset at temperatures around 800°  C independent of the stage of textural equilibration. The granulites were partially amphibolitized at upper amphibolite facies temperatures of 600–700°  C. Following cooling, a possible reheating to greenschist facies temperatures around 500°  C is indicated by prograde zoning in magnetite–ilmenite pairs. Mineral assemblages are not suitable for barometry, but a conservative estimation of the garnet-in reaction at given whole-rock compositions suggests maximum pressures in the granulite facies of around 5 kbar, and similar pressures are indicated by phengite barometry for the greenschist facies. The P–T  path of granulite–amphibolite metamorphism is one of slow cooling from magmatic temperatures with heterogeneous deformation. The thinning of the pre-Andean (Precambrian–Triassic) crust was apparently compensated by the magmatic underplating and this special tectonomagmatic setting caused the prolonged residence of the accreted rocks at midcrustal levels.     

安徽省大别山南部宿松杂岩变质作用研究

宿松杂岩的变质作用可分为３个阶段：早期、主期和晚期阶段。主期阶段的矿物组合在云母片岩中为石榴石＋多硅白云母＋石英＋磁铁矿±钠云母±绿帘石／黝帘石；在白云母钠长（二长）片岩和片麻岩中为石榴石＋多硅白云母＋钠长石＋石英＋绿帘石／黝帘石±冻蓝闪石；在石榴石钠长角闪岩中为石榴石＋冻蓝闪石＋钠长石＋黝帘石＋石英±钠云母±金红石／磁铁矿。根据多种地质温压计和变质反应可以推测主期变质条件为：Ｔ＝５２０℃～５８０℃，Ｐ＝１．２～１．４ＧＰａ，地热梯度为１２℃／ｋｍ，相当于高压过渡型。晚期阶段变质条件为：Ｔ＝４６０℃～４８０℃，Ｐ＝０．６～０．７ＧＰａ，为中压绿帘角闪岩相。宿松杂岩的变质条件介于其南部的蓝闪绿片岩相和北部的榴辉岩相之间，三者是扬子板块向华北板块之下俯冲到不同深度的产物。