扬子东南大陆边缘晚前寒武纪古海洋演化的稀土元素记录

本文采用中子活化方法分析了晚震旦～早寒武纪１９件样品的稀土元素组成,发现硅质岩石ＲＥＥ配分形式有着复杂的变化,初步可以划分为五种类型,包括“台地型”、“红海型”、“海水型”及两种特殊的配分形式。剖面上Ｃｅ异常由小到大的演变反映了古海洋底层水由缺氧环境向氧化条件的逐渐转化。正Ｅｕ异常的出现代表了热水沉积事件的存在。     

航磁梯度数据解释新方法在迁安铁矿勘探中的应用

为更加清晰和准确地利用磁梯度数据获得地质体的分布特征,笔者采用解析信号总水平导数法和梯度欧拉反褶积技术组合实现磁梯度数据的解释,解析信号总水平导数的极值可有效地圈定出矿体的分布范围,梯度欧拉反褶积法可有效地避免背景异常的干扰,从而准确地给出磁性体的位置和深度信息。理论模型证明解析信号水平导数法和梯度欧拉反褶积法的组合可准确地获得磁性体的水平范围和深度。应用于河北迁安地区磁梯度数据的解释,圈定出5个呈条带状分布的较大型铁矿藏,埋深在200~450 m。     

Quaternary Climate and Environment in the Lop Nur, Xinjiang

Since the middle Early Pleistocene (1.20 Ma B.P.), the desert steppe climate and environment have predominated in the Lop Nur area, Xinjiang, characterized by warm humid epochs interrupted by dry cold intervals. The grain-size and magnetic susceptibility curves record 30 climatic oscillations, each with a ca. 40 ka cycle, in the area since 1.2 Ma B.P., which reflects the controlling effects exerted by the astronomic factor on the environment. The Quaternary sedimentary environment in the Lop Nur gradually changed from a fresh lake through a brackish lake to a saline lake, showing a spiral evolution, and finally it evolved into a playa.     

Simulation of groundwater level recovery in abandoned mines,Fengfeng coalfield,China

Abandoned mines are of high potential risk as they could be a large underground storage of pollutants(heavy metals and organic wastes, etc.). Various physical, chemical and biological reactions would take place when groundwater flows into underground spaces, which makes abandoned mine a huge potential hazard to groundwater environment. The recovery of groundwater level is one of the key elements controlling the reactions and causing such hazards. This paper simulated groundwater level recovery processes in the abandoned mines, Fengfeng coalfield by using the computer program FEFLOW. The paper integrated the pipe flow model, "three zones" model and groundwater inrush(discharge) model in the simulation of groundwater in the complex laneway-aquifer system. Groundwater flow in the laneway systems was considered pipe flow and described in Bernoulli equation. The water-bearing medium(coal seam roof) overlying the laneway systems was divided into "three zones" composed of the caving zone, fissure zone and bending zone based on the disruption degrees of previous mining. Groundwater in the Ordovician limestone aquifer(bottom of coal seam) flowing into laneway systems was considered a major inrush/recharge source, and its flow rate was calculated by an inrush(discharge) model which was newly developed in this study and incorporated into FEFLOW. The results showed that it would take approximately 95 days for groundwater in abandoned mines to recover to regional groundwater level elevation, and the total amount of water filling up would be about 1.41195×10~7 m~3, which is consistent with the actual data. The study could be of theoretical and practical significance to mitigate abandoned mines' hazards and improve mine groundwater utilization.     

昌邑市生态地质环境保护对策

昌邑市位于山东省北部莱州湾南岸,南北狭长,南部为丘陵,中部和北部为平原,潍河纵贯南北。在查明市域内各种生态环境地质问题的基础上,将昌邑市划分为4个生态地质环境保护区和1个生态地质环境保护带,针对各区存在的主要问题,提出了不同的保护对策。     

清镇式铁矿矿石特征及加工技术性能探讨 ——以猫场铝土矿红花寨、白浪坝矿段铁矿床为例

贵州中部清镇、修文等地石炭系铝土矿底部的铁矿俗称为"清镇式铁矿",与黔中铝土矿共同赋存于下石炭统九架炉组之中。本文在实际勘探工作及通过勘探阶段在钻孔副样中采集的铁矿进行可选性试验基础上,以同类型的清镇市猫场铝土矿红花寨、白浪坝矿段铝土矿共生的铁矿为研究对象,指出该类型铁矿矿石自然类型为赤铁矿和褐铁矿;工业类型为需选铁矿石;矿石矿物主要为赤铁矿,部分赤铁矿水化为针柱状褐铁矿;脉石矿物则以白云石和方解石为主。矿石中可供利用的主要元素是铁,造渣组分主要是硅、铝,其次为钙、镁等。试验结果表明,该矿采用一粗一精一扫的强磁选试验可获得铁精矿TFe含量55. 58%,回收率80. 11%的良好指标,精矿中各元素含量达到H55-Ⅰ类赤铁精矿质量要求,在当前市场条件下采用推荐工艺处理该矿可获利。结论对黔中铝土矿资源的综合勘查开发具有借鉴意义。     

多源数据融合技术在矿产开发动态监测中的应用——以天津北部山区为例

在把遥感数据融合技术引入到地学数据的处理中,尝试将不同分辨率的遥感影像、采矿登记数据、地球化学数据等进行融合,取得了较好的效果。通过对比分析天津北部山区数十年来资源开采情况,评价其对环境所产生的影响,指出工作区存在部分违规采矿行为,很好地实现了对本区采矿行为及影响的动态监测,为地方的资源管理提供了科学依据。     

吉林南部三棵榆树组火山岩的成因:锆石U-Pb年龄和Hf同位素证据

锆石LA-ICP-MS U-Pb测年结果显示,吉林南部地区三棵榆树组粗面岩形成于118 Ma的早白垩世晚期。岩石地球化学研究表明,三棵榆树组粗面岩的SiO2含量为65.11%～65.61%,富碱(K2O=6.29%～7.28%,Na2O=3.71%～4.21%),属于钾玄岩系列,弱过铝质(A/CNK=1.05～1.12),含镁指数Mg#=9～16;稀土元素总量较高(∑REE=317.72×10-6～371.30×10-6),轻重稀土分馏明显(LaN/YbN=19.50～22.80),Eu负异常较弱(δEu=0.75～0.81);微量元素富集Rb、Th、Zr、K,明显亏损Nb、Ta和Sr等,显示典型的大陆地壳特征。锆石的176Hf/177Hf比值介于0.282 206～0.282 309之间,εHf(t)值介于-13.32～-16.97之间,Hf模式年龄(TDM2)介于2.0～2.6 Ga之间,平均为2.2 Ga。上述特征表明,吉林南部地区早白垩世粗面岩主要来源于古元古代地壳物质的部分熔融,形成于伸展构造环境。     

The Removal of Dissolved Metals by Hydroxysulphate Precipitates during Oxidation and Neutralization of Acid Mine Waters, Iberian Pyrite Belt

This study examines the removal of dissolved metals during the oxidation and neutralization of five acid mine drainage (AMD) waters from La Zarza, Lomero, Esperanza, Corta Atalaya and Poderosa mines (Iberian Pyrite Belt, Huelva, Spain). These waters were selected to cover the spectrum of pH (2.2–3.5) and chemical composition (e.g., 319–2,103 mg/L Fe; 2.85–33.3 g/L SO₄⁼) of the IPB mine waters. The experiments were conducted in the laboratory to simulate the geochemical evolution previously recognized in the field. This evolution includes two stages: (1) oxidation of dissolved Fe(II) followed by hydrolysis and precipitation of Fe(III), and (2) progressive pH increase during mixing with fresh waters. Fe(III) precipitates at pH < 3.5 (stages 1 and 2) in the form of schwertmannite, whereas Al precipitates during stage 2 at pH 5.0 in the form of several hydroxysulphates of variable composition (hydrobasaluminite, basaluminite, aluminite). During these stages, trace elements are totally or partially sorbed and/or coprecipitated at different rates depending basically on pH, as well as on the activity of the SO₄⁼ anion (which determines the speciation of metals). The general trend for the metals which are chiefly present as aqueous free cations (Pb²⁺, Zn²⁺, Cu²⁺, Cd²⁺, Mn²⁺, Co²⁺, Ni²⁺) is a progressive sorption at increasing pH. On the other hand, As and V (mainly present as anionic species) are completely scavenged during the oxidation stage at pH < 3.5. In waters with high activities (> 10⁻¹) of the SO ₄⁼ ion, some elements like Al, Zn, Cd, Pb and U can also form anionic bisulphate complexes and be significantly sorbed at pH < 5. The removal rates at pH 7.0 range from around 100% for As, V, Cu and U, and 60–80% for Pb, to less than 20% for Zn, Co, Ni and Mn. These processes of metal removal represent a significant mechanism of natural attenuation in the IPB.     

中印度洋脊Edmond热液区黄铁矿的标型特征及其对海底成矿作用环境的指示

对中印度洋脊Edmond热液区的丘顶和丘坡进行电视抓斗取样,获得了大量的金属硫化物等热液作用产物样品。在进行细致的矿相学分析基础上,对硫化物中黄铁矿的标型特征及其演化进行了详细研究。结果表明,Edmond热液区的黄铁矿可分3种类型,其形态标型和成分标型分别具有以下特征:Ⅰ型:呈自形立方体状,S/Fe原子数比接近于2.00,微量元素具有高Cu,低Zn、As、Pb、Ni和Ag的特点,Cu/Zn值高,平均可达4.26;Ⅱ型:呈半自形立方体状,S/Fe原子数比平均2.03,具有高Zn、Co、低Cu的特点,Cu/Zn值(平均0.04)低;Ⅲ型:主要呈胶状、莓球状,S/Fe原子数比平均2.04,具有Ag、Pb、Zn、As元素富集的特点,Cu/Zn值介于前两者之间(平均1.09)。根据硫化物中矿物共生组合关系,认为这3类黄铁矿分别对应高温、中高温和低温成矿作用,黄铁矿的形态和成分能很好地指示热液区的成矿环境和成矿条件的演变。