河南栾川钼铅锌多金属矿集区土壤重金属累积及源解析

河南栾川钼铅锌多金属矿集区内长期矿产资源开发产生了大量的重金属,目前研究区农田表层土壤重金属累积及不同种类矿业活动对其影响尚不明晰。本文选取研究区内5个典型小流域,采集河流沿岸29条水平土壤剖面上95件农田表层土壤样品,采用极谱法测定Mo,电感耦合等离子体质谱法测定Cd,X射线荧光光谱法测定Cr、Cu、Pb和Zn,原子荧光分光光度法测定Hg和As含量,通过地累积指数法、内梅罗综合污染指数法和潜在生态风险指数法分别评价重金属的累积特征、污染程度和生态风险;采用多元统计分析和PMF模型对表层土壤重金属的来源进行解析。结果表明：研究区农田表层土壤中主要污染物为Mo,局部为Hg;除Cr外,其他重金属均不同程度地受到周边矿业活动的影响;5个流域土壤重金属富集程度依次是：北沟河＞淯河＞石宝沟＞陶湾北沟＞伊河。北沟河土壤总体为重污染,中等生态风险,其他流域土壤总体污染程度为轻度,生态风险等级为轻微;但不同流域均存在重金属污染较重和生态风险较强的点位。典型横向土壤剖面分析表明,近岸部分土壤重金属富集程度明显高于远岸土壤。研究区农田表层土壤重金属来源于自然源（32.9%）、铅锌矿矿业活动（30.6%）、钼矿矿业活动（26.8%）和金矿矿业活动（9.7%）。     

A new tree fern stem,Tempskya zhangii sp. nov. (Tempskyaceae) from the Cretaceous of Northeast China

A new Cretaceous tree fern species from the family Tempskyaceae, Tempskya zhangii sp. nov., from Keshan County, Heilongjiang Province, Northeast China, is described based on silicified fragments. The species is characterized by dichotomizing stems embedded in a matrix of adventitious roots, together forming a solid and compact false trunk. The dorsiventral stems are composed of solenosteles, and their internodes are short with 2–3 (rarely 4) leaf traces. A three-layered cortex includes a sclerenchymatous outer zone, parenchymatous middle zone, and an inner zone composed of sclerenchyma band and parenchyma cells. The pith consists of a parenchymatous outer zone and sclerenchymatous inner zone. The petiole has a single C- or U-shaped vascular strand. The adventitious root has diarch xylem surrounded by an inner sclerenchymatous and an outer parenchymatous cortex. In possessing these characters, T. zhangii is more similar to T. wyomingensis from the Cretaceous of North America than to other species of Tempskya. However, the Chinese species distinctly differs from T. wyomingensis in having a sclerenchymatous outer cortex, parenchymatous middle cortex, and sparse parenchyma in the xylem. It is the first record of Tempskya from China and the fourth from Asia. This species, together with Cyatheaceae, Osmundaceae, Cycadeoidaceae, and conifers found in the same region constituted the plant community at the time.     

奇异性理论在弱异常信息提取中的应用—以冀北隐伏中-酸性侵入岩体为例

冀北地区是河北省矿产资源重要聚集地之一,成矿条件优越,其中中-酸性侵入岩体与银铅锌多金属矿床成矿密切相关。然而,大量的第四系覆盖压制了一些深部及隐伏弱异常成矿信息,使得常规化探方法在该覆盖区提取效果微弱。本文运用奇异性分析及主成分分析对冀北1：20万水系沉积物常量元素化探数据进行分析处理,提取区内成矿元素弱异常,并将其与未进行奇异性处理的结果进行对比。结合区域地质背景、物化探资料圈定覆盖区内与中-酸性侵入岩体有关的异常区,对成矿作用、成矿规律进行分析、讨论,以期揭示区内元素富集规律。结果显示,上述组合方法可以有效提取元素弱异常并进行成矿有利区圈定,并且圈定位置与已知岩体位置、区域构造条件相吻合,共圈出隐伏异常点7个,推测其为成矿远景区。     

四川甘洛铅锌矿集区闪锌矿Rb-Sr等时线年龄及其地质意义

四川甘洛铅锌矿集区位于扬子地块西南缘的川滇黔铅锌成矿带北段,是四川主要的铅锌产地,具有重要经济价值。为研究该矿集区铅锌成矿时代、成矿大地构造背景和成矿机制,以支撑区域找矿勘查,在区内选择赤普和尔呷地吉两个典型铅锌矿床开展闪锌矿Rb-Sr同位素体系研究,获得Rb-Sr等时线年龄246 ± 17 Ma（MSWD= 2.3）,表明区内铅锌矿化作用发生于早三叠世,与古特提斯洋闭合时限吻合;闪锌矿(87Sr/86Sr)i值变化于0.71061~0.71393,高于幔源87Sr/86Sr值0.70355及峨眉山玄武岩87Sr /86Sr值0.704979~0.706938,低于基底岩石87Sr /86Sr值0.7243~0.7288,暗示成矿物质主要来源于地壳。综合前人研究,认为在古特提斯洋闭合背景下,强烈造山运动诱发盆地卤水深循环并萃取基底地层中的成矿物质,在峨眉山玄武岩岩浆活动的热动力条件下,含矿流体沿马拉哈断裂进一步迁移沉淀形成了赤普和尔呷地吉铅锌矿床。马拉哈深大断裂及造山作用派生的层间或断层破碎带、碳酸盐岩地层是甘洛地区主要的控矿要素。     

造山型金矿容矿建造分类、成矿模式及找矿勘查

造山型金矿床指造山过程中形成的后生脉状金矿床,受构造、建造双重控制,是全球最重要的金矿勘查类型。按容矿岩石建造的不同,造山型金矿可分为绿岩带型（包括绿片岩型、BIF型和花岗- 片麻岩型3个亚类型）、浊积岩型、碳酸盐岩型和浅成侵入岩型,构成了造山型金矿床完整的成矿谱系。不同类型之间具有紧密的时空和成因联系,可互为找矿标志。绿岩组合和浊积岩系具有高的金丰度,既是容矿岩系,也是重要的矿源层,多类型造山作用驱动大规模区域性流体活动,造就了造山型金矿省/巨型成矿带,岩浆流体叠加和“热机效应”是形成超大型金矿床的重要因素。构建了多源区域性流体+岩浆流体叠加的地壳连续成矿模型和造山型金矿区域成矿模式,强调了多旋回造山作用对造山型金矿的成矿意义。“富金矿源层+剪切变形带+浅成侵入岩”组合是大型金矿系统的勘查选区标志,靶区优选的目标是获取找矿潜力大的优质矿权;矿权区勘查的优先目标是发现可规模化露天开采的矿床（体）,通过化探异常评价和浅钻追索次生富集带,可快速发现主矿体;矿区深部找矿（深度>300 m）潜力巨大,主攻目标是资源量大、品位高的热液通道相的厚板状或筒状矿体。     

基于新型探测资料对西安一次弱降水预报失误的原因分析

利用微波辐射计、激光测风雷达、多普勒雷达、相控阵雷达等新型探测资料、地面加密观测资料、ERA5再分析及多模式数值预报结果对2022年4月24日西安城区一次弱降水预报出现明显失误的原因进行分析,结果表明：(1)全球数值预报模式和中尺度数值预报模式对本次过程西安城区均报有明显降水,主要原因为模式对低层相对湿度预报明显偏大;(2)多种新型探测数据分析认为近地层湿度条件较差及中层的绝对水汽含量低,中层的干暖空气不利于成云致雨,垂直上升运动不强,且由于低层非常干燥,使水滴在下沉过程中蒸发,从而无法形成雨滴下落,这些原因共同造成西安城区无降水,低层相对湿度预报偏大是造成这次西安城区降水预报失误的主要原因之一;(3)造成西安城区近地层湿度条件差的原因是城市干热岛效应和低层干暖平流输送,且降水云团翻越秦岭后其湿空气绝热下沉至城区后出现增温降湿,使得城区形成较为深厚的干层,即使有雨滴在下落过程中也会造成更强的蒸发,这也是城区没有降水的重要原因之一;(4)预报员主观预报订正出现空报主要是源于对边界层水汽、抬升条件等关键降水要素缺乏订正能力,且对大城市的干热岛效应和秦岭山区地形影响研究不足。     

海洋水声环境调查数据处理系统的设计与实现

针对目前海洋环境调查现状,结合国内现有的技术条件和现有的处理方法、原理,详细论述了海洋水声环境调查处理系统软件主要功能的设计及关键技术,该系统软件满足海洋调查的需求,极大提高了海洋环境数据处理的自动化、数字化和信息化程度。     

Heterogenous zircons from Mesozoic igneous rocks in the North China Craton and their tectonic implications

Based on a synthesis of zircon inheritance from Mesozoic igneous rocks in the eastern portion of the North China Craton （NCC） , it is proposed that inherited zircons with Neoproterozoie ages identified from these rocks are of a heterogenous derivation from the Yangtze/South China block, rather than from the NCC itself. The mechanism that introduces these zircons incorporated into the NCC is likely by tectonic underplating during the Triassic continental subduction of the Yangtze block beneath the NCC. Tectonic addition of abundant crustal materials represented by the heterogenous zircons into the NCC, probably along Moho or weak interfaces within the NCC＇s crust, led to the crustal thickening in the NCC. These heterogenous materials, either as （partial） source rocks or as contaminants of the magmas generated during an extension environment following the crustal thickening, were reworked and therefore have significant contribution to petrogenesis of the Mesozoic igneous rocks. The crustal thickening resulted from the tectonic underplating, as indicated by the distribution extent of the heterogenous zircons, is spatially similar to that of the lithospheric thinning, with both mainly occurring in the eastern segment of the NCC. This is probably suggestive of an intrinsic relation between the thickening and thinning events during the Mesozoic evolution of the NCC.     

Early Cretaceous Metasomatized Lithospheric Mantle beneath the Central Jiangnan Orogen in South China: Geochemical and Sr-Nd Isotope Evidence from the Tuanshanbei Dolerite

It is well established that Cretaceous magmatism in the South China Block (SCB) is related to the Paleo-Pacific subduction. However, the starting time and the associated deep crust-mantle processes are still debatable. Mafic dike swarms carry important information on the deep earth (including mantle) geodynamics and geochemical evolution. In the Jiangnan Orogen (South China), there is no information on whether the Mesozoic magmatic activities in this region are also directly related to the Pacific subduction or not. In this study, we present detailed zircon U-Pb geochronological, whole-rock element and Sr-Nd isotope data for Early Cretaceous Tuanshanbei dolerite dikes, and provide new constraints on the condition of the lithospheric mantle and mantle dynamics of the SCB during that time. LA-ICP-MS zircon U-Pb dating suggests that this dolerite erupted in the Early Cretaceous (~145 Ma). All samples have alkaline geochemical affinities with K2O + Na2O = 3.11–4.04 wt%, K2O/Na2O = 0.50–0.72, and Mg# = 62.24–65.13. They are enriched in LILE but depleted in HFSE with higher initial 87Sr/86Sr ratio (0.706896–0.714743) and lower εNd(t) (?2.61 to ?1.67). They have high Nb/U, Nb/La, La/Sm and Rb/Sr, and low La/Nb, La/Ta, Ce/Pb, Ba/Rb, Tb/Yb and Gd/Yb ratios. Such geochemical signatures suggest that the fractional crystallization is obvious but crustal contamination play a negligible role during magmatic evolution. Tuanshanbei dolerite were most likely derived from low-degree (2%–5%) partial melting of a phlogopite-bearing mantle material consisted of ~85% spinel peridotite and ~15% garnet peridotite previously metasomatized by asthenosphere-derived fluids/melts with minor subduction-derived fluids/melts. Slab-rollback generally lead to the upwelling of the hot asthenosphere. The upwelling of asthenosphere consuming the lithospheric mantle by thermo-mechanical-chemical erosion. The lithospheric mantle may have partially melted due to the heating by the upwelling asthenosphere and lithospheric extension. It is inferred that the Tuanshanbei dolerite might be associated with the initial slab rollback and corresponding lithospheric extension occurred potentially at ca. 145 Ma.