重金属锌,铅对菲律宾蛤仔的急性毒性试验

本文研究了必需元素Ｚｎ及非必需元素Ｐｂ对菲律宾蛤仔的急性毒性作用，得到Ｚｎ对其的４８ｈＬＤ５０和９６ｈＬＤ５０分别为１４７．９１、１６．４０ｍｇ／ｄｍ＾３；Ｐｂ对其的４８ｈＬＤ５０和９６ｈＬＤ５０分别为３１．６２、１４．２８ｍｇ／ｄｍ＾３。估算得到Ｚｎ、Ｐｂ对菲律宾蛤仔的安全浓度分别为０．８２、０．７１ｍｇ／ｄｍ＾３。     

粤东成矿地质背景及银-铜-铅-锌成矿物质来源探讨

通过对粤东地区地层和岩石中成矿元素含量和区域地质背景的分析,认为粤东地区铜铅-锌-银成矿作用与燕山期的构造-岩浆作用关系密切,成矿物质中银-铜-锌以下地壳来源为主,铅则以上地壳及沉积地层来源为主。     

Metal sources of the Navan carbonate-hosted base metal deposit, Ireland: Nd and Sr isotope evidence for deep hydrothermal convection

Nd and Sr isotope analyses are presented for gangue mineral samples from the giant carbonate-hosted Navan Zn–Pb deposit, Ireland, and for rocks from which Navan metals may have been derived. Analysis of gangue minerals spanning the Navan paragenetic sequence reveals systematic evolution in the composition of the mineralising fluid. Early fluid represented by replacive dolomite exhibits the lowest initial ⁸⁷Sr/⁸⁶Sr ratio (0.7083–0.7086), closest to that of the host limestone and to Lower Carboniferous seawater, and the highest ¹⁴³Nd/¹⁴⁴Nd ratio (0.51161–0.51176). Later generations of dolomite, barite and calcite, which encompass sulphide precipitation, have higher initial ⁸⁷Sr/⁸⁶Sr ratios (maximum 0.7105) and lower initial ¹⁴³Nd/¹⁴⁴Nd ratios (minimum 0.51157). All samples have initial Nd isotope ratios that are too low to have been acquired only from the host limestone. Drill core samples of presumed Ordovician volcanic and sedimentary rocks from beneath the Navan orebody have ¹⁴³Nd/¹⁴⁴Nd and ⁸⁷Sr/⁸⁶Sr ratios at the time of mineralisation of 0.51184–0.51217 and 0.7086–0.7138, respectively. The data are interpreted to indicate mixing of sulphide-rich, limestone-buffered brine, with a metal-bearing hydrothermal fluid, which had passed through sub-Carboniferous rocks, consistent with published fluid inclusion and S isotope data. The ¹⁴³Nd/¹⁴⁴Nd ratio of this basement-derived fluid is too low to have been imparted by flow through the Devonian Old Red Sandstone, as required in models of regional fluid flow in response to Hercynian uplift. Irrespective of whether such regional fluid flow occurred, the hydrothermal Nd must have been derived from sub-Devonian rocks. These conclusions broadly support the hydrothermal convection cell model in which brines, ultimately of surface origin, penetrated to a depth of several kilometres, leaching metals from the rocks through which they passed. The data also support increasing depth of penetration of convection cells with time. Metals were subsequently precipitated in carbonate rocks at sites of mixing with cooler, sulphide-rich fluids. However, comparison of the Navan hydrothermal gangue Nd–Sr isotope data with data from Lower Palaeozoic rocks strongly suggests that the latter cannot alone account for the “basement” signature. As the Navan deposit lies immediately north of the Iapetus Suture, this suggests that the Laurentian margin includes Precambrian basement.     

华南下寒武统镍钼矿层中铜铅锌矿物的发现及意义

华南扬子地块是我国古热水沉积成矿作用最为发育的地区之一,其热水沉积特性最早引起我国学者的关注。华南下寒武统黑色岩系中赋存多个与热水沉积成矿作用相关的大型、超大型重晶石矿床与N i-Mo-U-V多金属富集层。进一步研究分布在华南扬子地块黑色岩系中的金属、非金属矿床成因及其地球化学特征,对认识华南乃至全球晚震旦—早寒武世生物与环境演化有着十分重要的意义。本文对华南下寒武统镍-钼富集层矿石进行电子探针研究,识别出黄铜矿、黝铜矿等铜的独立矿物;闪锌矿等锌的独立矿物;方铅矿、白铅矿等铅的独立矿物。研究表明,在镍-钼矿石中这些矿物的发现为镍-钼矿层是热水沉积作用产物提供了直接的矿物学证据。     

吉林省土壤中有效锰、铜、钼和锌含量的时空变化

选择吉林省的五个大豆种植区(敦化、桦甸、榆树、农安、白城)、四个水稻种植区(白城、九台、延吉、梅河口)及3个草场分布区(镇赉、洮南、大安)，对其土壤中有效锰、铜、钼和锌的含量在过去20年的变化作了比较和分析。经研究表明：吉林省土壤中有效锰和有效铜含量较20年前有所增高，有效钼含量总体呈降低趋势，中部部分地区和东部地区土壤有效锌含量降低，其余地区含量增高。空间分布东部高于中西部。     

扬子地块西缘灯影组层控铅锌矿床成因的地球化学论证

扬子地块西缘灯影组层控铅锌矿床成因的地球化学论证邵世才（有色总公司北京矿产地质研究所，北京１０００１２）李朝阳（中国科学院地球化学研究所，贵阳５５０００２）关键词层控铅锌矿床地球化学矿床成因扬子地块西缘１矿床地质特征扬子地块西缘灯影组铅锌矿床呈南北向...     

Comparison of Cu and Zn cycling in eutrophic lakes with oxic and anoxic hypolimnion

Data on the cycling of Cu and Zn in two eutrophic lakes are presented: Lake Greifen that becomes seasonally anoxic in its hypolimnion and Lake Sempach that is aerated during winter and oxygenated during summer. They suggest that hypolimnetic oxygenation 1) enhances the release of copper from the sediment but 2) also accelerates the entrapment and deposition of Cu and Zn by freshly formed Mn- and Fe-oxides.     

凤太矿集区金铅锌矿地球化学特征及找矿方向

通过对金、铅锌矿成矿规律和地球化学特征的研究,讨论陕西凤太矿集区今后的找矿方向,并初步圈定了4处找矿靶区。     

Genetic significance of fluid inclusions in the CSA Cu–Pb–Zn deposit, Cobar, Australia

CSA mine exploits a ‘Cobar-type’ Cu–Pb–Zn±Au±Ag deposit within a cleaved and metamorphosed portion of the Cobar Supergroup, central New South Wales. The deposit comprises systems of ‘lenses’ that encompass veins, disseminations and semi-massive to massive Cu–Pb–Zn ores. The systems and contained lenses truncate bedding, are approximately coplanar with regional cleavage and similarly oriented shear zones and plunge parallel to the elongation lineation. Systems have extreme vertical continuity (>1000 m), short strike length (400 m) and narrow width (100 m), exhibit vertical and lateral ore-type variation and have alteration haloes. Models of ore formation include classical hydrothermalism, structurally controlled remobilisation and polymodal concepts; syntectonic emplacement now holds sway.Fluid inclusions were examined from quartz±sulphide veins adjacent to now-extracted ore, from coexisting quartz–sulphide within ore, and from vughs in barren quartz veins. Lack of early primary inclusions precluded direct determination of fluids associated with D₂–D₃ ore and vein emplacement. Similarly, decrepitation (by near-isobaric heating) of the two oldest secondary populations precluded direct determination of fluid phases immediately following D₂–D₃ ore and vein emplacement. Post-decrepitation outflow (late D₃ to early post-D₃) is recorded by monophase CH₄ inclusions. Entrained outflow of deeply circulated meteoric fluid modified the CH₄ system; modification is recorded by H₂O+CH₄ and H₂O+(trace CH₄) secondary populations and by an H₂O+(trace CH₄) primary population. The contractional tectonics (D₂–D₃) of ore emplacement was superseded by relaxational tectonics (D_4P) that facilitated meteoric water penetration and return flow.Under D₂ prograde metamorphism, entrapment temperatures (Tt) and pressures (Pt) for pre-decrepitation secondary inclusions are estimated as Tt300–330 °C and Pt1.5–2 kbar≈Plith (the lithostatic pressure). Decrepitation accompanied peak metamorphism (T350–380 °C) in mid- to late-D₃, while in late-D₃ to early post-D₃, essentially monophase CH₄ secondary inclusions were entrapped at Tt350 °C and Pt=1.5–2 kbar≈Plith. Subsequently, abundant CH₄ and entrained meteoric water were entrapped as H₂O+CH₄ secondaries under slowly decreasing temperature (Tt330–350 °C) and constant pressure (Pt1.5–2 kbar). Finally, with increasingly dominant meteoric outflow, H₂O+(trace CH₄) populations record decreasing temperatures (Tt>300 to <350 down to 275–300 °C) at pressures of Phydrostatic<Pt (1 kbar) <Plith (1.5 kbar).The populations of inclusions provide insight into fluid types, flow regimes and P–T conditions during parts of the deposit's evolution. They indirectly support the role of basin-derived CH₄ fluids in ore formation, but provide no insight into a basement-sourced ore-forming fluid. They fully support post-ore involvement of meteoric water. The poorly constrained entrapment history is believed to span 10 Ma from 395 to 385 Ma.