河岸带潜流层温度示踪流速计算方法

为揭示低温水影响下的河岸带潜流层的温度场和流场分布特性,利用野外水温水位实时监测试验,研究河岸带潜流层温度场在不同季节、不同空间位置上的分布特性,并利用水温资料计算获得地下水流速。结果表明:河岸带潜流层温度场在夏季和冬季分别呈现出"上暖下冷"和 "上冷下暖"的温度分层现象;通过对温度示踪方法的4种计算方法进行分析比较,得到Hatch相位法计算的地下水流速具有较高的准确性,在2014年12月15—31日时段内流速大小为1.03×10-4~7.96×10-4m/s,在空间上,断面深度增加,地下水流速降低,且不同深度流速曲线接近平行。     

The North Atlantic Oscillation (NAO) and Europe Blocking and Their Impacts on Extreme Snowstorms: A Review

Large-scale, low frequency modes such as the North Atlantic Oscillation(NAO)and blocking, have an important modulation on the northern hemisphere weather and climate. In this paper, the physical mechanism studies on inter-decadal and decadal variability of NAO and blocking were summarized. The relationship between NAO regime transitions and the interannual variability of NAO in winter during was examined by using a statistical approach. The time-space relationship between NAO and European blocking were discussed. Based on two extreme cold and snowstorm events, the impacts on local weather especially the extreme events within the life cycle (two weeks) of the NAO and blocking were further examined. It was found that the frequently occurrence of the Eurasian extreme snowstorm was closely related to the special combination of NAO and blocking regime. In addition, the development of theoretical modes for NAO and blocking was discussed and issues that remain to be solved were proposed.     

Active Characteristics and Paleoearthquakes in the West Kalpin Nappe Since the Holocene,SW Tianshan Mountain

the Kalpin nappe is an important multiple thrust system. It is important to study the Cenozoic tectonic of the Tianshan Mountain. Holocene active characteristics and paleoearthquake of the Kalpin nappe can be used to evaluate the neotectonic of this area. In this paper, we accurately measured the fault scarp in the front of three thrust-fold faults and analyzed paleoearthquake events in the trenches of the Kalpin nappe. Using the ¹⁰Be exposure age, we obtained those geomorphic surface ages and paleoearthquake times. The result showed that the slip rates of the west Kalpintag fault, aozitag fault and the tuoketag fault were 1.45(+1.68/-0.44) mm/a, 0.81(+0.35/-0.19) mm/a and (0.3±0.05) mm/a, respectively since the Holocene. The slip rate indicated that the increased activity transferred from back-row fault to front-row fault and accorded with the piggy-back propagation model in the Tianshan Mountain. Displacements and recurrence intervals of paleoearthquakes was similar to the slip rate characteristics. It also showed paleoearthquakes in the front row fault were stronger than paleoearthquakes of the back row fault. The strong paleoearthquake which caused the highest surface rupture happened in the Kalpintag fault. The interval of paleoearthquakes was about 4 ka and the displacement of every paleoearthquake was about 3 m in the west Kalpintag fault; the interval of paleoearthquakes was about 2 ka and the displacement of every paleoearthquake was about 1m in the aozitag fault; the tuoketag fault ruptured only one paleoearthquake since 7 ka. The Piqiang tear fault was the tectonic result of different shortening rate between the west Kalpin system and the east Kalpin system. The shortening rate of west Kalpin system was obviously stronger than the east Kalpin system. The huge separation distance was near 20 km between the east and the west back-row fault. Because the slip rate of system transferred to the front-row fault in the piggy-back propagation model, the separation distance (~4 km) between the east and the west front-row fault was increasing.     

黑河新生地区中侏罗世花岗质岩石锆石U-Pb年龄、地球化学特征及岩石成因

黑河新生地区西古兰河以北二长花岗岩的LA-ICP-MS锆石U-Pb同位素测试结果表明,其形成时代为中侏罗世((163.8±1)Ma)。这些中侏罗世二长花岗岩属于弱过铝质高钾钙碱性系列的Ⅰ型花岗岩,明显富集大离子亲石元素(Rb、Ba、Th)和亏损高场强元素(Zr、Hf、Nb、Ta),元素Sr具有明显的负异常,表明其原始岩浆起源于地壳火成岩的部分熔融。结合区域资料同时代火成岩的组合特征和古太平洋板块的构造演化,认为该二长花岗岩形成于活动大陆边缘,而其形成的地球动力学背景可能为古太平洋板块向欧亚板块俯冲造山后的伸展环境。     

甘肃宝积山盆地中侏罗世石拐茨康叶表皮构造及古环境意义

甘肃宝积山盆地中侏罗统窑街组发现茨康类植物化石,通过对其外部形态和表皮构造研究,认定为石拐茨康叶(Czekanowskia(Vachrameevia)shiguaiensis)。对比当前化石及其现存最近对应种(the nearest living equivalent species)—Ginkgo biloba L.的气孔比率,得到宝积山盆地在中侏罗世的古大气CO_2体积分数为1.55×10~(-3),数值接近GEOCARBⅢ碳平衡模型的拟合曲线,表明茨康叶属植物也是恢复古大气CO_2体积分数的良好材料。同时,通过角质层特征进行古环境重建,结果表明宝积山盆地在中侏罗世时期气候较为温和湿润。     

滨里海盆地Z油田油藏类型与成藏因素研究

Z油田主要含油层系包括白垩系-中侏罗统低幅度背斜构造油藏、中三叠统盐檐断鼻油藏和上三叠统岩性圈闭油藏3种油藏类型。通过对紧密围绕盐有关的构造和有效盐窗这两个影响Z油田油气成藏的关键因素的研究认为成藏模式为"盐下生成、盐窗沟通、盐边盐间断层输导、高点聚集、后期保存"。Z油田油源充足,盐窗大而有效,多种有效的输导体系,圈闭类型多而好,埋深适中,储盖层发育且配置良好,侧向遮挡条件具备且后期保存条件良好,可作为今后勘探首选目标区。     

构造物理模拟和PIV有限应变分析对构造裂缝预测的启示

油气储层中构造裂缝发育与有限应变状态关系密切,为了探索有限应变分析与构造裂缝预测的新技术方法,此次研究设计完成了一组单侧挤压收敛模型的物理模拟实验,并引入粒子图像测速(PIV,Particle Image Velocimetry)技术对实验过程进行了定量化分析。实验模型在垂向上为含粘性层的多层结构,实验结果形成了一个肉眼可见的箱状褶皱。通过PIV技术可以获取实验模型变形演化过程中各阶段的位移场数据,计算出各阶段的增量应变,实现从初始状态到褶皱形成之后整个变形过程的有限应变分析,探讨构造裂缝成因机制和分布规律,进行定量化裂缝预测。挤压变形过程初期,应变分布范围很广,有限应变较弱(约4%~8%),在挤压方向上的线应变表现为弱压应变,在垂向上的线应变表现为弱张应变,这种现象是褶皱和断层产生前平行层缩短和层增厚的纯剪变形结果,也是区域型张裂缝和剪裂缝形成的主要机制。褶皱和断层即将发育之时至发育之后,应变局限在断层发育的剪切带及附近区域,有限应变表现为较强(达20%)的剪切应变和剪切张应变,是断层面附近简单剪切变形作用的结果,也是局部型剪裂缝和张剪裂缝形成的主要机制。     

黄河三角洲滨海湿地演化过程中的碳埋藏效率及其控制因素

2007年在黄河三角洲布设了一口浅钻ZK4,孔深28.3 m,对获取的岩心样品进行了详细的沉积学观测及含水量、有机碳、总碳和营养成分的实验室分析测试。通过ZK4孔的地层分析,将其划分为7种沉积环境,揭示了滨海湿地地质演化过程。并利用AMS14C测年方法,结合黄河改道的历史记录,运用历史地理学和沉积地质学综合分析的方法对黄河三角洲沉积环境进行了年代划分,并计算了黄河三角洲不同沉积环境沉积物的沉积速率和碳的加积速率。结果表明:总碳和有机碳与除硫和磷元素以外的各营养成分都呈良好的线性相关;碳、氮、磷的加积速率与沉积物的沉积速率呈极显著正相关关系(R0.89,p0.01),沉积物的沉积速率是碳、氮、磷的加积速率的主控因素;虽然现代黄河三角洲沉积物有机碳浓度较低(1%),但由于沉积物的高沉积速率,现代黄河三角洲沉积物有机碳的平均加积速率达到2878.23 g/(m2·a),远高于世界其他高有机碳浓度的湿地,因此是很好的碳汇地质体。     

新疆博格达山北麓白杨河剖面页岩地球化学特征及其地质意义

通过博格达山北麓白杨河剖面芦草沟组页岩的地球化学特征的综合研究,讨论了芦草沟组页岩的元素富集特征和沉积环境以及源区物源特征和构造背景。结果表明:1研究区页岩P元素极为富集,这受控于页岩中凝灰质火山灰夹层的广泛发育;2对比于世界页岩微量元素分布,白杨河页岩相对富集Li、B、Pr、Tb、Dy、Ho、Er、Tm和Lu元素,其他元素相对亏损;3白杨河剖面页岩地化参数揭示芦草沟组自下而上气候由温湿向干热转变,进而引起水体由淡水向咸水的转变和还原程度的进一步加强;4物源区遭受低级-中等风化程度,物源类型主要为长英质火成岩,其次为铁镁质火成岩;5物源区大地构造背景以大陆岛弧-活动大陆边缘构造背景为主。     

西天山Muruntau金矿床地质和S-Pb同位素示踪

Muruntau金矿床位于乌兹别克斯坦卡拉库姆板块北缘,是世界规模最大的金矿床。赋矿地层为一套发生绿片岩相浅变质作用的含炭复理石建造。矿区主要经历了四期变形变质作用(D1-D4),矿体受构造控制明显,就位于桑格龙套-塔姆德套与穆龙套-道古兹套剪切带的构造交汇部位,金矿化主要产于次级韧脆性断裂中。对矿床的矿石硫化物及地层开展了系统S、Pb同位素研究,结果表明石英脉型及蚀变岩型矿石中硫化物的δ34S变化范围较大,集中于2.2‰~6.1‰,其中蚀变岩型矿石中毒砂样品δ34S值集中于2.2‰~4.6‰,含金石英脉中硫化物样品δ34S值集中于3.0‰~6.1‰,方解石-石英脉中硫化物样品δ34S值集中于3.5‰~4.0‰,表明矿石中硫主要来源于地层,可能有少量岩浆硫加入。2件黑色页岩中毒砂206Pb/~(204)Pb为19.906~20.378,~(207)Pb/~(204)Pb为15.730~15.750,208Pb/~(204)Pb为38.388~39.894;3件含金石英脉中黄铁矿206Pb/~(204)Pb为18.848~19.431,~(207)Pb/~(204)Pb为15.669~15.736,208Pb/~(204)Pb为38.346~38.879;2件方解石脉中毒砂206Pb/~(204)Pb为18.715~19.563,~(207)Pb/~(204)Pb为15.639~15.740,208Pb/~(204)Pb为38.640~39.295。6件地层岩石样品的铅同位素组成206Pb/~(204)Pb为19.416~20.600,~(207)Pb/~(204)Pb为15.675~15.746,208Pb/~(204)Pb为38.876~39.431。矿石铅与地层铅均落于上地壳与造山带之间,矿石铅显示较大的跨度,且与地层岩石铅具有部分重合,显示成矿物质具有双重来源,与赋矿地层及造山期变质流体均表现出密切成因联系。结合矿床地质特征总结分析,沉积地层的物质准备+多期构造运动驱动变质流体运移(D1-D4)+岩浆热液的后期叠加应该是Muruntau巨量金属富集的关键控制因素。