习水县岩溶水系统ρ(Sr2+)、ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)分布特征及其应用

通过对流域内不同类型水取样分析,发现流经不同岩层的地下水具有不同的ρ(Sr2+)、ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)值.一般来说,流经砂岩层的基岩裂隙水ρ(Sr2+)低,而ρ(Sr)/ρ(Ca)、ρ(Sr)/ρ(Mg)值较高,当砂岩中的基岩裂隙水受到灰岩岩溶水或煤系地层水补给时,其ρ(Sr2+)、ρ( Sr...     

直流电法在水文地质勘查中的应用研究

直流电法主要有电阻率法（联合剖面法和电测深法）和充电法,广泛应用于工程地质和水文地质勘察中,如地基勘察,水库涌水处理,矿山岩溶水测量等。直流电法能有效地圈定含水体的位置,确定其产状,特别是选择的方法组合应用效果更佳,为工程水文地质提供准确的资料。     

Yanshanian Magma-Tectonic-Metallogenic Belt in East China of Circum-Pacific Domain (Ⅰ):Igneous Rocks and Orogenic Processes

Ｙａｎｓｈａｎｉａｎｍａｇｍａ－ｔｅｃｔｏｎｉｃ－ｍｅｔａｌｏｇｅｎｉｃｂｅｌｔｏｆｔｈｅＥａｓｔＣｈｉｎａｉｓａｐａｒｔｏｆｔｈｅｃｉｒｃｕｍ－Ｐａｃｉｆｉｃｄｏｍａｉｎ．Ａｌｏｔｏｆｐａｐｅｒｓｈａｖｅｂｅｅｎｐｕｂｌｉｓｈｅｄｔｏｄｉｓｃｕｓｓ...     

Al_2O_3-SiC-C砖渣静态侵蚀后的显微结构分析

铁水预处理用鱼雷罐、铁水罐的炉衬多为Ａｌ２Ｏ３ＳｉＣＣ砖,随着铁水脱硫量的加大,耐火材料的侵蚀也较严重。而现在由于市场需要钢水中的磷含量要求较低,脱磷处理过程中由于国外多采用氧化铁系脱磷剂,氧化亚铁对石墨的氧化很大,对炉衬侵蚀也大,这就要求对Ａｌ２Ｏ３ＳｉＣＣ砖的性能进行改进以适宜工艺需要。国内对脱磷的研究较少,实际生产对铁水进行脱磷处理的厂家也很少。为探讨脱硫、磷剂对耐火材料的影响,本文对不同脱硫、磷剂侵蚀Ａｌ２Ｏ３ＳｉＣＣ砖后的残砖的显微结构进行了分析,探讨了铝碳化硅碳砖的侵蚀原…     

CT技术在土体结构性分析中的应用初探

提出了一种利用 Ｃ Ｔ 技术定量评价黄土结构性的方法。利用该方法对不同压实度的黄土进行了初始扫描,并从 Ｃ Ｔ 数和 Ｃ Ｔ 图像两方面分析压实黄土的初始结构,得到一些有益的结果。     

Progressive,episodic deformation in the Mexican Fold–Thrust Belt (central Mexico): evidence from isotopic dating of folds and faults

We used illite Ar/Ar dating to obtain absolute ages of folds and shear zones formed within the Mexican Fold–Thrust Belt (MFTB). The methodology takes advantage of illite dating in folded, clay-bearing layers and the ability to obtain accurate ages from small-size fractions of illite using encapsulated Ar analysis. We applied our approach to a cross-section that involves folded Aptian–Cenomanian shale-bentonitic layers interbedded with carbonates of the Zimapán (ZB) and Tampico–Misantla (TMB) Cretaceous basins in central-eastern Mexico. Basinal carbonates were buried by syn-tectonic turbidites and inverted during the formation of the MFTB in the Late Cretaceous. Results from folds and shear zones record different pulses of deformation within this thin-skinned orogenic wedge.

Mineralogical compositions, variations in illite polytypes, illite crystallite size (CS), and Ar/Ar ages were obtained from several size fractions in limbs and hinges of the folds and in the shear zones. 1M_d-illite polytype (with CS of 6–9 nm) dominates in two folds in the TMB while 2M₁-illlite (with CS of 14–30 nm) dominates in the third fold, in the ZB, and in the fold/shear zone. From west (higher grade) to east (lower grade): Ar retention ages indicate shearing occurred at ~84 Ma in the westernmost shear zone, folding at ~82 Ma in the ZB with subsequent localized shearing at ~77 Ma, and Ar total gas ages constrain the time of folding at ~64 Ma on the west side of the TMB and ~44 Ma on the eastern edge. These results are consistent with the age and distribution of syn-tectonic turbidites and indicate episodic progression of deformation from west to east.     

Early Permian extensional shearing of an Ordovician granite: The Saint-Eutrope “C/S-like” orthogneiss (Montagne Noire,French Massif Central)

Dating the magmatic events in the Montagne Noire gneiss dome is a key point to arbitrate between the different interpretations of the Late Carboniferous–Early Permian tectonics in this southern part of the Variscan belt. The Saint-Eutrope orthogneiss crops out along the northern flank of the dome. We show that the protolith of this orthogneiss is an Ordovician granite dated at 455 ± 2 Ma (LA-ICP-MS U-Pb dating on zircon). This age is identical to that previously obtained on the augen orthogneiss of the southern flank, strongly suggesting that both orthogneiss occurrences have the same Ordovician protolith. The Saint-Eutrope orthogneiss experienced intense shearing along the Espinouse extensional detachment at ca. 295 Ma (LA-ICP-MS U-Pb-Th on monazite), an age close to that determined previously on mica by the ³⁹Ar-⁴⁰Ar method and contemporaneous with the emplacement age of the syntectonic Montalet granite farther to the west. This normal sense shearing reworked previous fabrics related to Variscan thrusting that can be still observed in the augen orthogneiss of the southern flank, and is responsible for the spectacular “C/S-like” pattern of the Saint-Eutrope orthogneiss. This work also shows that care is needed when dealing with C/S-type structures, since they can develop not only in syntectonic intrusions, but also in orthogneisses affected by an intense secondary deformation, at decreasing temperature.     

青海省土壤有机碳储量估算及其源汇因素分析

收集了青海省第二次土壤普查资料的2 856个土壤统计剖面数据,计算了20世纪80年代青海省土壤0～20 cm和0～65 cm深度的土壤有机碳密度,根据1∶400万数字化土壤类型图,统计了不同类型土壤的土壤有机碳储量。结合本研究采集的105个表层土壤数据,估算了青海省典型地区土壤有机碳近30年来的年均变化量。研究建立了土壤有机碳含量与温度、降雨等气候因子的关系方程,根据青海省土地利用现状估算了不同时期土地利用方式变化对青海省土壤碳源汇转化的影响。结果显示:(1)0～20 cm表土层SOCD20加权平均值为4.509 kg/m2,其值在各类型土壤间差异较为显著,SOCR20为2.953 Pg;0～65 cm的SOCD65加权平均值为13.597 kg/m2,SOCR65为8.904 Pg。由于受气候、土壤类型、植被类型、海拔等因素的影响,青海省土壤有机碳密度的分布呈现自东南向西北递减的带状分布特征;(2)近30年来青海省有机碳含量明显下降;(3)根据气象站的资料,分析了近50年来的年均气温变化趋势,预测在全球变暖背景下青藏高原土壤将表现出碳源效应,而研究区愈加明显的人类活动影响、大面积草地退化等土地利用方式改变也是造成土壤碳释放的主要原因之一。     

柴达木盆地东北部中新世沉积物色度记录的气候变化

中新世是新生代古气候变化的关键时期。本文以柴达木盆地东北部瑙格剖面18.4～6.9Ma沉积物为研究对象,通过对沉积物颜色指标的测定与分析,获得该时段沉积物高分辨率颜色指标变化序列。发现色度值变化与氧化—还原作用有关,红度值与赤铁矿相对含量呈正相关。结合其它资料分析表明,柴达木盆地东北部地区中新世气候变化为18.4～14.2Ma相对暖湿阶段、14.2～7.7Ma相对冷湿阶段、7.7～6.9Ma相对干冷阶段,其变化可能受到全球温度变化的影响,气候转型主要导致了该区沉积相和沉积物色度的变化。