Sediment routing in the Zagros foreland basin: Drainage reorganization and a shift from axial to transverse sediment dispersal in the Kurdistan region of Iraq

In the northwestern sector of the Zagros foreland basin, axial fluvial systems initially delivered fine-grained sediments from northwestern source regions into a contiguous basin, and later transverse fluvial systems delivered coarse-grained sediments from northeastern sources into a structurally partitioned basin by fold-thrust deformation. Here we integrate sedimentologic, stratigraphic, palaeomagnetic and geochronologic data from the northwestern Zagros foreland basin to define the Neogene history of deposition and sediment routing in response to progressive advance of the Zagros fold-thrust belt. This study constrains the depositional environments, timing of deposition and provenance of nonmarine clastic deposits of the Injana (Upper Fars), Mukdadiya (Lower Bakhtiari) and Bai-Hasan (Upper Bakhtiari) Formations in the Kurdistan region of Iraq. Sediments of the Injana Formation (~12.4–7.75 Ma) were transported axially (orogen-parallel) from northwest to southeast by meandering and low-sinuosity channel belt system. In contrast, during deposition of the Mukdadiya Formation (~7.75–5 Ma), sediments were delivered transversely (orogen-perpendicular) from northeast to southwest by braided and low-sinuosity channel belt system in distributive fluvial megafans. By ~5 Ma, the northwestern Zagros foreland basin became partitioned by growth of the Mountain Front Flexure and considerable gravel was introduced in localized alluvial fans derived from growing topographic highs. Foredeep accumulation rates during deposition of the Injana, Mukdadiya and Bai-Hasan Formations averaged 350, 400 and 600 m/Myr respectively, suggesting accelerated accommodation generation in a rapidly subsiding basin governed by flexural subsidence. Detrital zircon U-Pb age spectra show that in addition to sources of Mesozoic-Cenozoic cover strata, the Injana Formation was derived chiefly from Palaeozoic-Precambrian (including Carboniferous and latest Neoproterozoic) strata in an axial position to the northwest, likely from the Bitlis-Puturge Massif and broader Eastern Anatolia. In contrast, the Mukdadiya and Bai-Hasan Formations yield distinctive Palaeogene U-Pb age peaks, particularly in the southeastern sector of the study region, consistent with transverse delivery from the arc-related terranes of the Walash and Naopurdan volcano-sedimentary groups (Gaveh-Rud domain?) and Urumieh-Dokhtar magmatic arc to the northeast. These temporal and spatial variations in stratigraphic framework, depositional environments, sediment routing and compositional provenance reveal a major drainage reorganization during Neogene shortening in the Zagros fold-thrust belt. Whereas axial fluvial systems initially dominated the foreland basin during early orogenesis in the Kurdistan region of Iraq, transverse fluvial systems were subsequently established and delivered major sediment volumes to the foreland as a consequence of the abrupt deformation advance and associated topographic growth in the Zagros.     

鄂尔多斯盆地直罗组地层岩性测井响应特征

为了准确划分直罗组地层岩性、识别地层及解译矿层,通过综合分析鄂尔多斯盆地4个主要铀矿集区侏罗系直罗组地层的定量伽马、自然电位、三侧向电阻率、密度4条测井曲线参数,采用归类统计和测井曲线形态分析,结果显示不同地区直罗组的伽马照射量率数值差异不大,东南缘地区电阻率值明显高于其他地区,密度值变化呈现\     

西昌盆地油气化探普查效果及下一步找油气方向

为了配合国家加快油气资源勘查步伐，四川石油管理局将西昌盆地作为下一步勘探重点地区，由于西昌盆地属勘探新区，各种地质、构造情况复杂，首先在该区实施了油气化探普查，油气化探普查结果证实了西昌盆地中部地区为油气泄漏特征，这与七坝1井结果吻合，同时发现了三个重点区域，指出盆地西部为下一步工作的重点地区，为下一步地震勘探指明找油气方向。     

沉积地层中成矿作用的碳同位素特征和含矿缺氧盆地成因新观点

沉积盆地内地层中碳的来源 ,根据其碳、氧同位素特征可归纳为 :海洋沉积碳酸盐碳、生物碳、热解非生物成因碳、大气淡水方解石碳和热卤水系统中的无机碳。热水成因的金矿及喷气 沉积矿床中的碳都具有深源成因的无机碳。深部含无机碳的热流体喷溢到海洋底部可以解释为扩张盆地底部形成的缺氧环境和含矿黑色页岩的主导原因     

A two-stage time series model for monthly hydrological projections under climate change in the Lim River basin (southeast Europe)

ABSTRACT

Climate change projections of precipitation and temperature suggest that Serbia could be one of the most affected regions in southeastern Europe. To prepare adaptation measures, the impact of climate changes on water resources needs to be assessed. Pilot research is carried out for the Lim River basin, in southeastern Europe, to predict monthly flows under different climate scenarios. For estimation of future water availability, an alternative approach of developing a deterministic-stochastic time series model is chosen. The proposed two-stage time series model consists of several components: trend, long-term periodicity, seasonality and the stochastic component. The latter is based on a transfer function model with two input variables, precipitation and temperature, as climatic drivers. The Nash-Sutcliffe model efficiency for the observed period 1950–2012 is 0.829. The model is applied for the long-term hydrological prediction under the representative concentration pathway (RCP) emissions scenarios for the future time frame 2013–2070.     

The lower marine to lower freshwater Molasse transition in the northern Alpine foreland basin (Oligocene; central Switzerland–south Germany): age and geodynamic implications

The Wilhelmine Alpe section near Immenstadt (Allgäu, south Germany), which represents one of the best continuously exposed outcrops within the northern Alpine foreland basin, has been analyzed for magnetostratigraphic and palynostratigraphic signals. The section comprises the marine-to-terrestrial transition from Lower Marine (UMM) to Lower Freshwater Molasse (USM) sediments. Based on the correlation of the local magnetic pattern with the geomagnetic polarity timescale (GPTS) and palynostratigraphic data, an age of about 31 Ma is suggested for the UMM–USM transition in the Wilhelmine Alpe section. A comparison with coeval magnetostratigraphic sections from central and eastern Switzerland indicates that the regression of the UMM sea along the southern margin of the Molasse basin occurred strongly heterochronously between 31.5 and 30 Ma. The heterochroneity is attributed to the deposition of fan-delta and alluvial fan sediments which document that the overall marine conditions during the UMM were accompanied by strong clastic input derived from the rising Alps. This clastic contribution had a much stronger influence on the depositional pattern than previously thought.     

两花岗岩体接触带铀系核素迁移的初步模拟

随着世界各国大力发展核电，放射性废料的安全处置已成为当今研究热点和前沿学科。高放废物深地质处置的安全性主要取决于处置库内放射性核素向生物圈的迁移程度。在侵入岩中，放射性核素主要是通过地下水沿岩石孔隙从处置库向生物圈迁移的。为了理解放射性核素在花岗岩体接触带的迁移行为，本文根据两花岗岩体接触带中样品的铀系核素放射性活度比值（^234U/^238U,^230Th/^234U,^226Ra/^230Th,^230Th/^238U)，利用 α-反冲（弹射）作用引起的放射性不平衡理论，计算了铀系核素子体^234U,^230Th,^226Ra在后期地下水的作用下在花岗岩体接触带及其裂隙内的迁出率、迁入率、并进行了质量平衡的计算。结果表明，经α-反冲作用进入流体的核素的迁出率要远大于因核素自然衰变的消亡率；裂隙充填物及裂隙能阻滞大量核素的迁移，其沉淀核素来自接触带花岗岩；花岗岩能强烈阻滞核素的迁移，可作为阻止放射性核素从核废料地下处置库向外迁移的有利天然屏障。     

Drainage basin object-based method for regional-scale landform classification: a case study of loess area in China

Landform classification is one of the most important procedures in recognizing and dividing earth surface landforms. However, topographical homogeneity and differences in regional-scale landforms are often ignored by traditional pixel- and object-based landform classification methods based on digital elevation models (DEMs). In this work, a drainage basin object-based method for classifying regional-scale landforms is proposed. Drainage basins with least critical areas are first delineated from DEMs. Then, terrain derivatives of mean elevation, mean slope, drainage density, drainage depth, and terrain texture are employed to characterize the morphology of the drainage basins. Finally, a decision tree based on the topographical characteristics of the drainage basins is constructed and employed to determine the landform classification law. The experiment is validated in the landform classification of regional-scale loess areas in China. Results show that clear boundaries exist in different landforms at the regional scale. Landform type in a specific region shows significant topographical homogeneity under its specific regional geomorphological process. Classification accuracies are 87.3 and 86.3% for the field investigation and model validation, respectively. Spatial patterns of classified landforms and their proximity to sediment sources and other factors can be regarded as indicators of the evolutionary process of loess landform formation.     

基于建设工程三维可视化规划报建技术应用研究

三维可视化是建设工程规划报建的最新发展方向,本文重点研究和总结一套基于建设工程规划报建的三维模型构建技术,并介绍了其基础数据的获取方法、三维可视化规划管理分析及网络发布的技术。     

辽宁查马屯铁矿三维地质建模及深部预测

查马屯铁矿是一处隐伏于中生代火山沉积岩之下的沉积变质型铁矿床,矿体规模大、埋藏浅,深部资源潜力巨大.利用三维地质体建模软件Creatar,通过收集钻孔数据,建立地质数据库,生成三维钻孔.通过剖面定义、单工程矿体圈定、剖面编辑、曲面连接,建立矿体三维模型.依据"点-线-面-体"的思路,建立了辽宁查马屯铁矿三维地质模型.模型显示,查马屯铁矿体西南段向北西倾斜,北东部向南东倾斜,呈北东东向展布,应沿该方向部署找矿.矿体与磁异常复合关系表明,2号矿体南部存在巨大找矿空间,查马屯村南部及北东部是下一步找矿勘探的重点方向.