山东半岛近岸海区全新世泥质沉积体研究现状

20世纪80年代以来,山东半岛近岸海区全新世泥质沉积体引起了地学界的关注,很多学者对其进行过研究并发表了众多相关论文。综合前人的研究成果认为,山东半岛全新世泥质沉积体受到黄海暖流和黄海沿岸流的共同作用,呈现出中间厚、向海向陆减薄的楔形,并沿山东半岛发育,其物质来源主要是黄河注入所带来的沉积物;在形成机制上,受到海平面上升、潮流和黄河入海口的迁移等多种因素的控制,成因复杂;在形成时间上,现今的研究成果普遍认为该泥楔形成于全新世冰后期海平面上升时期。对目前研究中仍存在的问题进行讨论,提出了山东泥楔的未来研究方向,指出应该建立多种水动力耦合作用下的泥沙输运与沉积模式,着重从海洋沉积动力学角度进行新的研究。     

山东半岛东部海域表层沉积物元素组成及物源指示意义

通过对山东半岛东部海域表层沉积物常量、微量元素、有机碳(TOC)以及碳酸盐(CaCO₃)等指标的分析,研究了该海域表层沉积物元素组成特征及其控制因素,并对物质来源进行了探讨。结果表明,山东半岛东部海域表层沉积物元素的平均组成与上陆壳(UCC)相比Al,K,Na,Mg,Fe,Ca,Cu和Zn等元素,相对较低,而Mn,Co,Ni,Cr以及REE元素含量较高,Si和Ti与UCC的含量相当。研究区砂粒级沉积物轻重稀土分异明显,(La/Yb)_N值与韩国河流的非常相近;其余粒级沉积物LREE分异较弱,标准化曲线与黄河沉积物的具有相似性。研究区沉积物的元素含量主要受控于源岩组成,存在明显的"粒级效应"。除此之外,Fe-Mn氧化物、生物碳酸盐等因素对元素组成产生一定影响。沉积物物源判别结果显示,山东半岛近岸及其东南部沉积物主要来源于黄河,该区域沉积物分布受山东半岛沿岸流及近岸潮流影响。研究区东北部为残留砂,其沉积物元素组成特征与朝鲜半岛和鸭绿江沉积物组成相近,表明研究区东北部砂质区沉积物代末次冰期低海平面时可能由朝鲜半岛或鸭绿江供应。     

Eco-environmental spatial characteristics of Fildes Peninsula based on TuPu models

This study applies a TuPu analysis to investigate ecological and environmental aspects of an Antarctic ice-free area, using Fildes Peninsula as an example. The TuPu unit was determined using a vector-grid mixed data model. Information from the eco-environment elements was effectively extracted, and was generalized into different classes by means of data mining technol- ogy. A series of single-factor thematic information TuPu models, such as topography, soil, animal and vegetation, and human activities for Fildes Peninsula were built in this study. The topography TuPu model contained information on elevation and slope. The soil TuPu model involved soil development stages and soil thickness information. The animal and vegetation TuPu model contained the distribution of animals, plant types, lichen cover and lichen height. The human activities TuPu model included popu- lation density and human disturbance index information. The landscape comprehensive information TuPu model of Fildes Penin- sula also was established, and contains twenty-nine landscape units and twelve types of combined environments. The study quan- titatively revealed the spatial morphology and correlation of the regional eco-environment based on the analysis of these TuPu models. From these models, we can draw the conclusion that there is a regular differentiation of eco-environment from the coastal bands to the central hills in Fildes Peninsula, and that the eco-environment condition of the eastern coasts is different from that of the western coasts. The eco-environmental spatial variation also differs greatly from north to south. Based on analysis of spatial correlation, the vegetation in Fildes Peninsula has the greatest correlation with human activity, and has a certain correlation with topography and soil. This research may provide a new technical approach and scientific basis for the in-depth study of Antarctic eco-environments.     

雷州半岛高桥红树林沉积物中砷的分布

采用五态连续提取法(SEP)对雷州半岛高桥红树林群落内外不同深度的沉积物砷含量进行测定.结果表明,高桥红树林湿地0~60cm深处沉积物中除Al-结合态砷和Ca-结合态砷含量低,难以检出外,交换态砷、残渣态砷、Fe-结合态砷皆可检出,沉积物砷积累以残渣态砷和 Fe-结合态砷为主,总砷测定含量为7.34±0.39~10.32±0.48 mg/kg,其中以20~40cm深处沉积物总砷测含量最多;不同深度沉积物砷含量中林内与林区外裸滩呈现不同的分布规律,林外裸滩-林缘-林内的表土总砷含量的分布呈波浪式分布,以林缘为最高,总砷达9.97±1.29 mg/kg,林内显著大于林外裸滩(p值<0.05),林内沉积物对砷的吸附强度较林外裸滩高     

A comparison of Jiaojia- and Linglong-type gold deposit ore-forming fluids: Do they differ?

The Jiaodong peninsula contains the most important concentration of gold deposits in China, which can be divided into Jiaojia-type and Linglong-type deposits based on mineralization style. The former is characterized by disseminated- and stockwork-style mineralization hosted in first-order regional faults, with relatively larger tonnages and lower gold grades. The latter is characterized by massive auriferous quartz veins commonly hosted in subsidiary second- or third-order faults, with smaller tonnage but higher grade orebodies. Despite these differences, both groups of deposits have the same alteration assemblages, mineral paragenesis, element concentrations, and ore-forming ages.The mainly Jiaojia-type Luoshan gold deposit and the mainly Linglong-type Fushan gold deposit are characterized by H-O-S-Pb isotope data that indicate the ore-forming fluids have a dominantly metamorphic source. The fluids were derived during the Yanshanian orogenic event, and were most likely associated with dehydration and decarbonization processes near the top of the subducting paleo-Pacific plate. The Linglong-type ores have relatively lighter calculated δ¹⁸O compositions (−3.9 to −2.3‰) than the Jiaojia-type ores (0.3–8.0‰), possibly because of a greater degree of mixing with meteoric water. Petrographic, cathodoluminescence, microthermometric, and laser Raman spectroscopic analyses of fluid-inclusion assemblages in quartz from the two types of ores indicate fluids were similar, in both cases characterized by medium–high homogenization temperatures (211–393 °C), significant CO₂ (∼15% mol), minor CH₄ (⩽18% in the carbonic phase), and low salinity (⩽11.2 wt% NaCl eq.). The Linglong-type ores, however, have a wider range of CO₂ and CH₄ concentration and salinity than the Jiaojia-type ores. Fluid immiscibility, occurred in main ore stage of both ore types, with the trapping conditions of 77–185 MPa and 284–328 °C, although the unmixing is more intense and widespread in the Linglong-type ores. Both fluid-wallrock interaction and fluid immiscibility are important gold-deposition processes in the two types, but immiscibility is more important in the Linglong-type ores and that has led to the typical higher gold grade.In general, there is little geochemical differences between the ore-forming fluids for Jiaojia- and Linglong-type gold deposits. Both Jiaojia- and Linglong-type ores can exist in a single deposit and form in the same metallogenic event. The Linglong-type ores developed as more massive veins, because of their location in zones of more extensive extension and they lack significant post-ore cataclastic deformation.     

Exploring for heavy minerals on Cape York Peninsula,Queensland, Australia

This paper describes the results of a preliminary study of the heavy mineral (HM) potential of the northwest coast of Cape York Peninsula in far north Queensland that was funded by the Queensland Government's Future Resources Program Industry Priorities Initiative. The study found that the northwest coast may have the potential to host world-class HM deposits. All the essential ingredients in a HM mineral system are present: fertile source rocks, effective transport mechanisms and abundant potential trap sites, particularly along the well-preserved Pleistocene coast.

The source rocks are Proterozoic metamorphic and Paleozoic granitic rocks of the Coen Inlier and Mesozoic sedimentary rocks of the Laura and Carpentaria basins, all of which crop out along the spine of the Peninsula. These rocks were exposed in the early Cenozoic and were vigorously eroded by seasonally active rivers throughout the Quaternary. Most of these rivers are currently carrying HM, and the zircon content in river sediments in the region is comparatively high. It is speculated that in the late Pleistocene HM delivered by rivers to the northwest coast were transported predominantly in a southwesterly direction, and trapped in the swash zone of prograding beaches. It is further speculated that at this time the coastline was deeply embayed with cliffs and headlands formed in bauxite, and that structural trap sites formed on the northeastern side of prominent headlands.

Pleistocene coastal sediments were partially reworked by Holocene coastal processes, and HM liberated by these processes may have been captured by prograding Holocene beach ridges. These Holocene beach ridges are not as extensive as the Pleistocene beach ridges but are more prominent, partly because they are less well vegetated. The Holocene coastline was probably more regular than the Pleistocene coastline, with fewer headlands to create structural traps. The modern coastline is relatively starved of river sediment because the Holocene and Pleistocene coastal sediments act as barriers to river flow.

It is recommended that ongoing exploration for HM in the region should focus on potential trap sites on the Pleistocene coast and that two sites, Vrilya Point and Jackson River, where structural traps may have been formed by coastal promontories, should be priority targets. It is also noted that if the exploration of Cape York Peninsula for HM deposits is to be effective, further research needs to be carried out into the geomorphological evolution of the west coast and, in particular, the role of cyclones in forming HM deposits in tropical climates.     

南极半岛屈韦维尔岛白垩纪中期火山岩浆作用及其构造指示:锆石U-Pb年代学和Hf同位素制约

南极半岛长期以来位于冈瓦纳古陆的西缘,是冈瓦纳古陆最后裂解的发生地。南极半岛内出露有大量的中新生代火成岩,关于其成岩期次、源区性质以及产出的动力学背景等尚存争议,从而影响到对南极半岛构造演化的认识。本文报道了南极半岛中部构造域屈韦维尔岛地区出露的安山质火山岩、闪长玢岩脉及其中闪长岩捕掳体的LA-MC-ICP-MS锆石UPb年代学和Hf同位素分析数据。其中含角砾安山质熔岩、安山质火山角砾岩、中粒闪长岩捕虏体和闪长玢岩脉4件样品的锆石U-Pb测年结果分别为103.3±1.7Ma、101.9±1.8Ma、92.0±1.2Ma和85.7±07Ma,表明该岛在白垩纪中期存在三幕火山岩浆作用事件:第一幕约为102Ma发生的强烈火山喷发;第二幕约为92Ma的闪长岩侵入作用;第三幕约为86Ma的闪长玢岩体侵入作用。锆石的Hf同位素原位分析结果表明,主要测点的εHf(t)值在+2.5~+7.9之间,平均值为+4.4,其一阶段Hf模式年龄为505~678Ma,表明白垩纪中期出露的火成岩可能由新元古代-寒武纪的亏损地幔物质部分熔融所形成。结合前人研究成果,得出本岛出露的火成岩形成于冈瓦纳古陆裂解过程所伴生的俯冲岛弧环境中,是构成南极半岛中部岩浆弧构造域的主体岩性之一。     

High resolution WRF climatic simulations for the Iberian Peninsula: Model validation

A high resolution atmospheric modelling study was done for a 20-year recent historical period. The dynamic downscaling approach adopted used the Max Planck Institute Earth System Model (MPI-ESM) to drive the WRF running in climate mode. Three online nested domains were used covering part of the North Atlantic and Europe, with a resolution 81 km, and reaching 9 km in the innermost domain which covers the Iberian Peninsula.This paper presents the validation of the WRF configuration, which is based on historic simulations between 1986 and 2005 and observational datasets of near surface temperature and precipitation for the same period. The validation was done in terms of comparison of probability distributions between model results and observations, as daily climatologies, spatially averaged inside subdomains obtained with cluster analysis of the observations, for each of the four seasons. In addition, Taylor diagrams are presented for each of the seasons and subdomains. This validation approach was repeated with the results of a new WRF simulation with the same parameterisations but forced by the ERA-Interim reanalysis. The capacity of the MPI-ESM driven WRF configuration to compare with observations and in a manner similar to the ERA-Interim driven WRF, ensures the capacity of the configuration for climate and climate change studies.Considering the difficulty to simulate extremes in long term simulations, the results showed a comfortable comparison of both models (forced by climate model and reanalysis results) with observations. This provides us confidence on the continuity of using the MPI-ESM driven WRF configuration for climate studies.     

Robust inferences on climate change patterns of precipitation extremes in the Iberian Peninsula

This work presents a methodology to make statistical significant and robust inferences on climate change from an ensemble of model simulations. This methodology is used to assess climate change projections of the Iberian daily-total precipitation for a near-future (2021–2050) and a distant-future (2069–2098) climates, relatively to a reference past climate (1961–1990).Climate changes of precipitation spatial patterns are estimated for annual and seasonal values of: (i) total amount of precipitation (PRCTOT), (ii) maximum number of consecutive dry days (CDD), (iii) maximum of total amount of 5-consecutive wet days (Rx5day), and (iv) percentage of total precipitation occurred in days with precipitation above the 95th percentile of the reference climate (R95T). Daily-total data were obtained from the multi-model ensemble of fifteen Regional Climate Model simulations provided by the European project ENSEMBLES. These regional models were driven by boundary conditions imposed by Global Climate Models that ran under the 20C3M conditions from 1961 to 2000, and under the A1B scenario, from 2001 to 2100, defined by the Special Report on Emission Scenarios of the Intergovernmental Panel on Climate Change.Non-parametric statistical methods are used for significant climate change detection: linear trends for the entire period (1961–2098) estimated by the Theil-Sen method with a statistical significance given by the Mann-Kendall test, and climate-median differences between the two future climates and the past climate with a statistical significance given by the Mann-Whitney test. Significant inferences of climate change spatial patterns are made after these non-parametric statistics of the multi-model ensemble median, while the associated uncertainties are quantified by the spread of these statistics across the multi-model ensemble. Significant and robust climate change inferences of the spatial patterns are then obtained by building the climate change patterns using only the grid points where a significant climate change is found with a predefined low uncertainty.Results highlight the importance of taking into account the spread across an ensemble of climate simulations when making inferences on climate change from the ensemble-mean or ensemble-median. This is specially true for climate projections of extreme indices such CDD and R95T. For PRCTOT, a decrease in annual precipitation over the entire peninsula is projected, specially in the north and northwest where it can decrease down to 400 mm by the middle of the 21st century. This decrease is expected to occur throughout the year except in winter. Annual CDD is projected to increase till the middle of the 21st century overall the peninsula, reaching more than three weeks in the southwest. This increase is projected to occur in summer and spring. For Rx5day, a decrease is projected to occur during spring and autumn in the major part of the peninsula, and during summer in northern Iberia. Finally, R95T is projected to decrease around 20% in northern Iberia in summer, and around 15% in the south-southwest in autumn.     

Recent trends of extreme precipitation indices in the Iberian Peninsula using observations and WRF model results

Spatial and temporal distributions of the trends of extreme precipitation indices were analysed between 1986 and 2005, over the Iberian Peninsula (IP). The knowledge of the patterns of extreme precipitation is important for impacts assessment, development of adaptation and mitigation strategies. As such, there is a growing need for a more detailed knowledge of precipitation climate change.This analysis was performed for Portuguese and Spanish observational datasets and results performed by the Weather Research and Forecast (WRF) model forced by the ERA-Interim reanalysis. Extreme precipitation indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices were computed, by year and season. Then, annual and seasonal trends of the indices were estimated by Theil-Sen method and their significance was tested by the Mann-Kendal test. Additionally, a second simulation forced by the Max Planck Institute Earth System Model (MPI-ESM), was considered. This second modelling configuration was created in order to assess its performance when simulating extremes of precipitation.The annual trends estimated for the 1986–2005, from the observational datasets and from the ERA-driven simulation reveal: 1) negative statistically significant trends of the CWD index in the Galicia and in the centre of the IP; 2) positive statistically significant trends of the CDD index over the south of the IP and negative statistically significant trends in Galicia, north and centre of Portugal; 3) positive statistically significant trends of the R75p index in some regions of the north of the IP; 4) positive statistically significant trends in the R95pTOT index in the Central Mountains Chain, Leon Mountains and in the north of Portugal.Seasonally, negative statistically significant trends of the CWD index were found in Galicia, in winter and in the south of the IP, in summer. Positive statistically significant trends of the CWD index were identified in the Leon Mountains, in spring, and in Galicia, in autumn. For the CDD index, negative statistically significant trends were seen in Valencia, in the spring, and, in Galicia and Portugal (north and centre), in summer. Positive statistically significant trends of the CDD index were found: in the east of the IP, in the winter; in the Cantabrian Mountain, in the spring; and, in the south of the IP, in summer. Regarding to the R75p index, negative statistically significant trends were found in Galicia, in winter and positive statistically significant trends in the north of Portugal, in spring and in the Central Mountains Chain and north of Portugal, in autumn. For the R95pTOT index, negative statistically significant trends were found over the Sierra Cuenca and Sierra Cazorla, in winter and positive statistically significant trends were found over the Sierra Cebollera, in winter and in Castile-la Mancha region, in spring.The results of the annual and seasonal trends of the extreme precipitation indices performed for observational datasets and the simulation forced by ERA-Interim, are similar. The results obtained for the simulation forced by MPI-ESM are not satisfactory, and can be a source of criticism for the use of simulation forced by MPI-ESM in this type of climate change studies. Even for the relatively short period used, the WRF model, when properly forced is a useful tool due to the similar results of Portuguese and Spanish observational datasets and the simulation forced by ERA-Interim.