Sources and sinks of sea salt in a newfoundland blanket bog

Over an oceanic peatland, the concentration of Na in fog averaged 38.1 mgl^?1 compared with 1.8 mgl^?1 in rain, resulting in a significant flux of mineral elements to the surface. Between 16 May and 20 June 1990 the average mass flux of Na to the bog surface by fog, rain, and dry deposition was 21.9, 10.4 and 7.0 mg m^?2 d^?1. There was little long-term storage of Na within the peatland system, where Na losses measured in stream runoff averaged 34.8 mg m² d^?1, and deep groundwater losses 4 mg m^?2 d^?1. Calcium and Mg were preferentially retained in the organic soil, whereas K was relatively mobile. Potassium tended to become concentrated in the unsaturated zone. Stream runoff had a consistently higher pH than groundwater, corresponding to higher Ca and Mg concentrations, which may have been from mineral sources in the headwater ponds. Otherwise, the stream water chemistry was closely related to groundwater in the upper layers of the peat deposit.     

Paleoproterozoic Extensional Structure and Its Controlling on Mineralization in the East of Liaoning Province

IntroductionThe area of eastern Liaoning is an importantmetal and nonmetal metallogenetic district in China,and the Liaohe group is one of the most importantstrata that hosts Pb, Zn, Au, B and Mg etcstratabound deposits. Up to now many geo1ogistssuch as Z…     

平阳矾山明矾石矿床岩石学特征及其成因浅析

在野外地质工作的基础上，通过对浙江平阳研山明矾石矿床的岩石学及地球化学特征进行认真的研究，进一步证实了矾山明矾山矿床是酸性火山气热液与中酸性火山碎屑岩内的碱性长石的交代中形成的。为了解释矿床的均一性，成矿的周期性和矿床单向依变分带等重要特征，我们重点研究了矿床中明矾石化和叶蜡石化的热力学性质，得出了K 活度和pH值是控制交代产物的重要因素的新结论，提出了该矿床交代成矿作用的新模型，并据此成功地解释了矿床的一些重要特征。     

Observations on the ecological importance of salt marshes in the Cumberland Basin,a macrotidal estuary in the Bay of Fundy

The Cumberland Basin, a 118 km² estuary at the head of the Bay of Fundy which has an average tidal range of about 11m, contains large tracts of salt marsh (15% of the area below highest high water). Low marsh (below about 0·9 m above mean high water) is composed almost exclusively of Spartina alterniflora while the vegetation on high marsh is more diverse but dominated by Spartina patens. Because of its higher elevation, high marsh is flooded infrequently for short periods by only extreme high tides. Low marsh is inundated much more frequently by water as much as 4m deep for periods as long as 4 h per tide. Temporal variability in the occurrence of extreme tides influences the flooding frequency of high marsh for any given month and year. Using a modification of Smalley's method, the mean annual net aerial primary production (NAPP) of low and high marsh is estimated to be 272 and 172 g C m^?2, respectively. Vegetation turnover times average 1·0 and 2·0 y for low and high marsh, respectively. Because of abundant tidal energy, much of the low marsh production appears to be exported and distributed widely about the estuary. Since high levels of turbidity suppress phytoplankton production, salt marshes produce approximately half of the carbon fixed photosynthetically in the Cumberland Basin. It is concluded that salt marshes play a major ecological role in the Cumberland Basin.     

Arsenic incorporation in a salt marsh ecosystem

Replicate portions of a Delaware salt marsh were enclosed in cylindrical microcosms and exposed to elevated levels of inorganic arsenic (arsenate). All biotic and abiotic components in dosed cylinders rapidly incorporated arsenic. Spartina blades showed the greatest arsenic enrichment, with dosed plants incorporating arsenic concentrations an order of magnitude higher than controls. Spartina detritus and sediments also exhibited greatly elevated arsenic concentrations. Virtually all of the arsenic was incorporated into plant tissue or strongly sorbed to cell surfaces. Thus, elevated arsenic concentrations in estuarine waters will be reflected in living and non-living components of a salt marsh ecosystem, implying that increased arsenic will be available to organisms within the marsh ecosystem.     

凤太矿田层控铅锌(铜)矿床的成矿物质来源探讨

秦岭凤太矿田层控铅锌(铜)矿床的金属物质、硫和成矿溶液主要来自深部基底的岩石,属海底喷流—沉积成因矿床。从这一理论认识出发可进一步分析控矿地质条件及今后在该区有效地寻找同类矿床。     

广西岩溶区金属硫化物矿床风化与元素表生迁移特征

对广西岩溶区三个铅锌硫化物矿床风化带观测结果表明，中低山岩溶区硫化物矿床具有更强烈的风化淋滤作用，但次生晕面积较小；岩溶平原区硫化物矿床风化与元素表生迁移特征较相似于非岩溶区的情况，表现在可产生较宽的ｐＨ偏低带和较大面积的次生晕     

元岭金矿蚀变破碎带特征及其找矿意义

根据对元岭金矿三条蚀变破碎带一般地质特征、微量元素特征的对比研究，并借鉴邻近矿区蚀变破碎带的矿化特征，本文阐明了元岭蚀变破碎带矿化的有利构造部位，总结了蚀变破碎带特征与矿化强度之间的关系，指出蚀变破碎带的矿化蚀变元素为中低温组合，矿化蚀变愈强则参与元素的种类愈多、数量愈大。围岩性质对矿化蚀变有一定影响，围岩中的易迁移亲铜元素和亲硫铁族无素对矿化有利。据此，为进一步成矿预测、评价蚀变破碎带的含矿性提供依据。     

On salinity regimes and the vertical structure of residual flows in narrow tidal estuaries

An examination is made of the circulation in narrow estuaries subject to a predominant tidal forcing. Velocity structures are derived separately for residual flow components associated with (a) river flow, (b) wind stress, (c) a well-mixed longitudinal density gradient and (d) a fully stratified saline wedge. Dimensionless parameters are introduced to indicate the magnitude of each component and these parameters are evaluated for 9 major estuaries, thereby revealing their sensitivity to each component.For a channel of constant breadth and depth, formulae are deduced for the length of saline intrusion, L. Comparisons with observed data show that such formulae may be used with confidence to predict changes in L arising from variations in river flow, tidal range or channel depths.The level of stratification is shown to be related to a product of two parameters, one associated with velocity structure and a second involving the square of the ‘flow ratio’ $\text{u}\text{u}\text{?}$ (i.e. residual velocity/amplitude of the tidal velocity). This relationship provides a simple classification system for estuarine stratification which can be used to indicate the sensitivity of any particular estuary to changing conditions.     

八庙—青山金红石矿床化学成分与成矿关系

本矿床是我国金红石矿床重要的成因及工业类型，为具有特定化学成分的岩石在特定变质条件下形成的。本文通过对大量数据的处理，查明了化学成分与成矿的关系：高Ａｌ２Ｏ３、ＭｇＯ、Ｆｅ２Ｏ３＋ＦｅＯ、Ｋ２Ｏ、Ｐ２Ｏ５、Ｈ２Ｏ＋、ＭｎＯ，低ＳｉＯ２、ＣａＯ、Ｎａ２Ｏ、ＣＯ２、Ｓ等，利于钛富集；高ＴｉＯ２、ＭｇＯ、Ｐ２Ｏ５、Ｓ，低ＳｉＯ２、ＣａＯ、Ｋ２Ｏ、Ａｌ２Ｏ３、Ｆｅ２Ｏ３／ＦｅＯ，利于金红石形成；高Ｓｃ、Ｚｒ、Ｎｉ、Ｚｎ及Ｌａ／Ｙｂ，低Ｙ、Ｎｂ、Ｔｈ、Ｃｄ、Ｂａ、Ｂｅ、ΣＲＥＥ，利于金红石纯度提高。对研究矿床成因及寻找新的同类矿床等有重要意义