Evolution of the Mesozoic Granites in the Xiong''''ershan-Waifangshan Region,Western Henan Province,China,and Its Tectonic Implications

Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-SrⅠ-type granite emplaced in the early stage (～160 Ma),Ⅰ-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma). Geochemical characteristics of the high-Ba-SrⅠ-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between～160 Ma and～115 Ma. The genesis of the early- and middle-stageⅠ-type granites could be linked to delamination of subducted lithosphere of the Qiniing orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qiniing -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios, which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons.     

考虑孔隙特性的压实黄土抗剪强度试验研究

以甘肃省临夏某机场场址黄土为研究对象,基于室内三轴剪切试验,研究了初始含水率和压实度对重塑黄土抗剪强度指标、应力路径、破坏强度的影响规律;结合室内电镜扫描试验得到的重塑黄土细观结构图像,定量分析了不同压实度下重塑黄土孔隙特性,并建立了孔隙特性与破坏强度之间的关系.研究结果表明:(1)不同初始含水率和压实度条件下重塑黄土应力G应变关系曲线形式为软化型、弱硬化型和强硬化型:7%含水率以下、90%压实度以上条件下为软化型,7%含水率、 85%压实度以下及9%含水率、90%压实度以上条件下为弱硬化型,其余条件下则为强硬化型; (2)重塑压实黄土应力路径曲线呈斜直线形式,曲线形式基本不受压实度和含水率影响;(3)重塑压实黄土抗剪强度指标、破坏强度随初始含水率的增加而减小,随压实度的增加而增大;(4)重塑压实黄土破坏强度与微、小孔隙含量成正比例关系,与中、大、特大孔隙含量及孔隙平均周长和面积成反比例关系.     

豫西熊耳山矿集区栾灵金矿床辉钼矿Re-Os同位素年龄及其地质意义

豫西栾灵金矿床地处熊耳山金多金属矿集区南部马超营断裂带北侧,金矿体产于构造破碎带中,呈钾长石石英脉体和蚀变岩产出,为本区一种新的金矿化类型。文章为厘定栾灵金矿床的成矿时代,采用辉钼矿Re-Os同位素定年方法,测得栾灵金矿6件辉钼矿样品的Re-Os同位素模式年龄为(161±3)Ma~(164±2)Ma,加权平均年龄(163±1)Ma(MSWD=0.68),等时线年龄(163±2)Ma(MSWD=1.5),表明栾灵金矿床形成于晚侏罗世早期。与祁雨沟、前河金矿等早白垩世(125 Ma)金矿相比,栾灵金矿的成矿作用早约38 Ma。这些年龄数据表明,该矿床在区域上可能与南泥湖-三道庄、上房沟钼矿等形成于同一成矿系统,它的发现为在熊耳山地区寻找相似成矿地质条件的金、钼矿床提供了依据。     

"三七"高炮防雹对昭苏县气象站雹日数影响的统计分析

根据昭苏县气象站1956－1973年（防雹前）和1974－1998年（防雹后）6－8月平均雹日数的变化，就“37”高炮防雹对下游地区雹日数的影响进行了统计分析。经计算，防雹后25年的平均雹日数比防雹前减少了3.8d，为了证明这一结果是人为影响还是自然变化，进行了序列检验和回归分析，表明，人工防雹使防区内雹日数显著减少，显著性水平分析达到0.001和0．01。     

基于EGM2008分析我国沿海陆地和岛礁高程异常

利用EGM2008地球重力场模型计算我国沿海13个省市的高程异常,结合实际的GNSS水准观测数据进行了比较分析,得出了GNSS水准实测的高程异常与EGM2008模型的高程异常之差的标准差是11 cm。     

地幔柱构造对松辽盆地及渤海湾盆地形成的制约

中国东部松辽盆地和渤海湾盆地形成与演化的深部动力学机制尚未得到很好的解释．通过对区域地震资料盆地沉积记录、火山岩岩石探针和大地构造演化历史的综合分析,认为地幔柱(柱头直径约500km)在晚侏罗世一晚白垩世时形成于松辽地区,经历了软流圈地幔上涌、地壳抬升与伸展、火山活动,导致松辽盆地的形成;由于华北板块向北移动,始新世时地幔柱(柱头直径600-800km)移动到京津一渤海湾地区,类似的地质过程形成了渤海湾盆地．渤海湾地幔柱的活动还可能是京津唐地区地震多发的根本原因。     

Phytoplankton forcing by a record freshwater discharge event into a large lagoonal estuary

We report here the response of the water column and phytoplankton biomass of a large lagoonal estuary to a record freshwater discharge event which followed from extraordinary hurricane activity. In the fall of 1999, three hurricanes passed over eastern North Carolina coast in a 7-wk period: Hurricane Dennis (August 24–September 5), Hurricane Floyd (September 14–17), and Hurricane Irene (October 13–16). The hurricanes delivered record rainfall to the watersheds of the Pamlico Sound, North Carolina, the second largest estuary in North America. Hurricane Floyd was followed by a 500-yr flood that displaced 80% of the volume of the Sound and delivered half the annual nitrogen (N)-nutrient load to this N-limited system.After Hurricane Floyd, buoyancy stratification restricted the mixed layer depth, dissolved inorganic nitrogen (DIN) in surface waters increased, and surface chlorophyll biomass increased up to 4-fold. Chlorophyll biomass did not increase to the potential indicated by residual DIN because of light-limitation attributable to suspended particulates, phytoplankton pigments, and colored dissolved organic material (CDOM).The discharge waters created hydrological conditions and supplied materials that we interpret to have both stimulated and restricted phytoplankton blooms. The effects of the discharge event on the hydrology and phytoplankton of the Pamlico Sound persisted about 6 months, after which it returned to its pre-event condition, attesting to the resilience of the system.     

Field validation of antioxidant enzyme biomarkers in mussels (Perna viridis) and clams (Ruditapes philippinarum) transplanted in Hong Kong coastal waters

Green-lipped mussels, Perna viridis, and Manila clams, Ruditapes philippinarum were sourced from “clean” sites in the Hong Kong region, depurated in a laboratory using uncontaminated filtered seawater for 8 days, and transplanted to a suspected gradient of chemically polluted sites in Hong Kong. After 14- and 28-days of field exposure, several antioxidant parameters including glutathione S transferase (GST), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were quantified in gill and hepatopancreas tissues. Whole body tissue concentrations of polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were determined in pooled site samples. Chemical analyses indicated that: (a) clams had higher levels of PAHs, PHCs, DDTs and PCBs, whereas mussels had higher hexachlorocyclohexane (HCHs) and there was no difference between species for dieldrin and remaining OCs; (b) Kat O should not be continued as a “clean” reference site for Hong Kong, because of the levels of contaminants measured and (c) PAH concentrations in the current survey were similar to those previously measured. Toxicological conclusions were: (a) antioxidant responses were different between species; (b) CAT and GST have highest utility in clams for field use in Hong Kong, whereas CAT in both gill and hepatopancreas tissue showed most potential in mussels; (c) significant induction of antioxidant responses over day 0 (excluding GPx in both tissues, and GST in mussel hepatic tissue); (d) groups of contaminants do not consistently induce antioxidant responses and (e) organochlorines and PCBs correlated significantly with CAT and GST in clam hepatopancreas and with CAT in mussel gill and hepatic tissue. Multivariate statistical techniques indicated little relationship between the site patterns for antioxidant responses and the contaminant gradients identified in body burden analysis.     

Antioxidant responses to polycyclic aromatic hydrocarbons and organochlorine pesticides in green-lipped mussels (Perna viridis): do mussels "integrate" biomarker responses?

Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs) are generally present in the marine environment in complex mixtures. The ecotoxicological nature of contaminant interactions, however, is poorly understood, with most scientific observations derived from single contaminant exposure experiments. The objective of this experiment was to examine dose-response relationships between antioxidant parameters and body contaminant levels in mussels exposed to different exposure regimes under laboratory conditions. Accordingly, the green-lipped mussel, Perna viridis, was challenged with a mixture of PAHs (anthracene, fluoranthene, pyrene, benzo[a]pyrene) and OC pesticides (alpha-HCH, aldrin, dieldrin, p,p'-DDT) over a 4 week period. Contaminants were delivered under four different dosing regimes, with all treatments receiving the same total contaminant load by the end of the exposure period. Antioxidant biomarkers were measured after 1, 2, 3 and 4 weeks, including glutathione (GSH), gluathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and lipid peroxidase (LPO). GST and CAT were induced in hepatic tissues in most of the exposure regimes, with the majority of significant induction occurring in a constant exposure regime and a two-step alternate exposure regime. Significant differences among exposure regimes were detected in the body burden of contaminants after 28 days. Hepatic CAT and GSH are proposed as potentially useful biomarkers as they showed good correlation with target contaminants and were not readily affected by different dosing patterns.     

Antioxidant responses to polycyclic aromatic hydrocarbons and organochlorine pesticides in green-lipped mussels (Perna viridis): Do mussels “integrate” biomarker responses?

Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs) are generally present in the marine environment in complex mixtures. The ecotoxicological nature of contaminant interactions, however, is poorly understood, with most scientific observations derived from single contaminant exposure experiments. The objective of this experiment was to examine dose-response relationships between antioxidant parameters and body contaminant levels in mussels exposed to different exposure regimes under laboratory conditions. Accordingly, the green-lipped mussel, Perna viridis, was challenged with a mixture of PAHs (anthracene, fluoranthene, pyrene, benzo[a]pyrene) and OC pesticides (α-HCH, aldrin, dieldrin, p,p′-DDT) over a 4 week period. Contaminants were delivered under four different dosing regimes, with all treatments receiving the same total contaminant load by the end of the exposure period. Antioxidant biomarkers were measured after 1, 2, 3 and 4 weeks, including glutathione (GSH), gluathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and lipid peroxidase (LPO). GST and CAT were induced in hepatic tissues in most of the exposure regimes, with the majority of significant induction occurring in a constant exposure regime and a two-step alternate exposure regime. Significant differences among exposure regimes were detected in the body burden of contaminants after 28 days. Hepatic CAT and GSH are proposed as potentially useful biomarkers as they showed good correlation with target contaminants and were not readily affected by different dosing patterns.