甘肃陇中黄土高原农业灌溉耗水系数监测试验研究     

凡炳文  仲复捷 《地下水》2020,(1):83-87,254

选择甘肃省临洮县洮惠渠灌区为试验研究区,通过直接观读、自动监测等技术手段,获取试验灌区的引水量、退水量、土壤墒情、降水量及蒸发量等水文基础数据。以水文监测基础数据为依据,采用引排差法、水分平衡法等相结合的方法,开展了农业灌溉耗水系数试验研究。初步试验结果表明:试验灌区灌溉期平均耗水系数为0. 730,典型地块灌溉期平均耗水系数为0. 671,2016年试验灌区降水量较常年偏少13. 0%~26. 3%,总体上属轻度干旱年份。该研究成果可为甘肃陇中黄土高原区水资源管理提供技术支撑。  相似文献   

Full moment tensor inversion constrained by double-couple focal mechanism for induced seismicity*          下载免费PDF全文

Yuyang Tan  Haijiang Zhang  Junlun Li  Chen Yin  Furong Wu 《地震科学（英文版）》2020,33(4):177-193

In this study, we propose a new method to determine full moment tensor solution for induced seismicity. This method generalizes the full waveform matching algorithm we have developed to determine the double-couple (DC) focal mechanism based on the neighbourhood algorithm. One major difference between the new method and the former one is that we adopt a new misfit function to constrain the candidate moment tensor solutions with respect to a reference DC solution in addition to other misfit terms characterizing the waveform matching. Through synthetic tests using a real passive seismic survey geometry, the results show the new constraint can help better recover the DC components of inverted moment tensors. We further investigate how errors in the velocity model and source location affect the moment tensor solution. The synthetic test results indicate that the constrained inversion is robust in recovering both the DC and non-DC components. We also test the proposed method on several real induced events in an oil/gas field in Oman using the same observation system as synthetic tests. While it is found that the full moment tensor solutions without using the DC constraints have much larger non-DC components than solutions with the DC constraints, both solutions are able to fit the observed waveforms at similar levels. The synthetic and real test results suggest the proposed DC constrained inversion method can reliably retrieve full moment tensor solutions for the induced seismicity.  相似文献   

2020年5月6日新疆乌恰5.0级和5月9日柯坪5.2级地震总结     

马亚伟  宋治平  杨文  解孟雨  苑争一  钟骏  李美  姚丽  邓世广  臧阳 《地震地磁观测与研究》2020,41(4):179-192

2020年5月6日、5月9日，新疆地区南天山西段先后发生乌恰5.0级和柯坪5.2级地震，系统总结2次地震发生前出现的地震活动和地球物理观测异常，其中：①地震活动：震前存在调制地震集中、地震窗、5级以上地震成组等中短期异常；②地球物理观测：2次地震震中附近震前出现形变、电磁和流体观测异常，其中形变异常3项、电磁异常4项、流体异常1项，主要分布在柯坪5.2级地震震中附近。通过对2次地震序列进行跟踪，发现：乌恰5.0级地震余震较少，震后60天内共记录M_L 3.0以上余震4次，最大震级为M_L 4.5；柯坪5.2级地震后余震较丰富，震后60天内共记录M_L 3.0以上余震10次，最大震级为M_L 4.7，计算得到序列h值为1.6，b值为0.73。综合分析认为，2020年5月新疆地区2次5级以上地震前存在的地震活动异常较少，但区域地震活动水平较强，主要存在具有中短期指示意义的地球物理观测异常。  相似文献   

2020年1月25日西藏丁青5.1级地震总结     

臧阳  薛艳  姚琪  解孟雨  苑争一  王阅兵  马亚伟  张小涛 《地震地磁观测与研究》2020,41(3):162-173

2020年1月25日，藏东昌都丁青地区发生5.1级地震，尽管此次地震发生在监测能力较低地区，但震前仍监测到小震调制比高值、低b值等地震活动中短期异常。文中系统总结了地震构造背景、震源物理参数、序列特征以及震前出现的地震活动和地球物理观测等异常，结果发现：震源机制解显示为拉张型破裂，最近断裂为巴青—类乌齐断裂；序列活动特征、序列h值和b值计算结果显示，此次地震为主余型地震序列。目前，藏东地区仍存在一些地震活动和地球物理观测异常，表明该地区存在发生6级以上地震的强震背景，丁青5.1级地震的发生未能缓解该地区强震危险性。  相似文献   

辽东岫岩地区下古生界碎屑锆石定年:罗迪尼亚和冈瓦纳超大陆在华北遗留的痕迹？     

董晓杰  陈煜嵩  刘正宏  徐仲元  沙茜 《岩石学报》2020,36(6):1857-1869

超大陆演化是地质研究的重要内容,华北克拉通与不同地质历史时期超大陆汇聚与裂解的联系对反演华北克拉通构造演化历史具有重要意义。本文在辽吉古元古代造山带中段的原划分为辽河群地层中首次识别出一套早古生代沉积建造。这套沉积建造与华北克拉通以浅海相的碳酸盐岩为主的早古生代沉积并不一致,以发育大量的陆源碎屑沉积为特征。我们对2件细砂岩分别进行了锆石LA-ICP-MS和SHRIMP U-Pb定年。定年结果显示,2件样品的最小年龄分别为～482Ma和～498Ma,反映了它们的最大沉积时代。2件样品的碎屑锆石年龄主要介于1600～500Ma,缺乏亲华北的物源信息,表明它们的物源主要来自于华北之外。2件样品年龄谱中最重要的峰值出现在格林威尔期和泛非期,表明华北克拉通曾与罗迪尼亚超大陆和冈瓦纳大陆存在联系。格林威尔期碎屑锆石可能来自于罗迪尼亚超大陆时期波罗地古陆物质在华北克拉通东缘的再循环;泛非期碎屑锆石可能来自于东冈瓦纳大陆的北缘造山带。  相似文献   

Using Mesoproterozoic sedimentary geochemistry to reconstruct basin tectonic geography and link organic carbon productivity to nutrient flux from a Northern Australian large igneous Province     

Bo Yang  Alan S. Collins  Grant M. Cox  Amber J. M. Jarrett  Steven Denyszyn  Morgan L. Blades  Juraj Farkaš  Stijn Glorie 《Basin Research》2020,32(6):1734-1750

The Beetaloo Sub-basin, northern Australia, is considered the main depocentre of the 1,000-km scale Mesoproterozoic Wilton package of the greater McArthur Basin – the host to one of the oldest hydrocarbon global resources. The ca. 1.40–1.31 Ga upper Roper Group and the latest Mesoproterozoic to early Neoproterozoic unnamed group of the Beetaloo Sub-basin, together, record ca. 500 million years of depositional history within the North Australia Craton. Whole-rock shale Sm–Nd and Pb isotope data from these sediments reveal sedimentary provenance and their evolution from ca. 1.35 to 0.85 Ga. Furthermore, these data, together with shale major/trace elements data from this study and pyrolysis data from previous publications, are used to develop a dynamic tectonic geography model that links the organic carbon production and burial to an enhanced weathering of nutrients from a large igneous province. The ca. 1.35–1.31 Ga Kyalla Formation of the upper Roper Group is composed of isotopically evolved sedimentary detritus that passes up, into more isotopically juvenile Pb values towards the top of the formation. The increase in juvenile compositions coincides with elevated total organic carbon (TOC) contents of these sediments. The coherently enriched juvenile compositions and TOC the upper portions of the Kyalla Formation are interpreted to reflect an increase in nutrient supply associated with the weathering of basaltic sources (e.g. phosphorous). Possible, relatively juvenile, basaltic sources include the Wankanki Supersuite in the western Musgraves and the Derim Derim–Galiwinku large igneous province (LIP). The transition into juvenile, basaltic sources directly before a supersequence-bounding unconformity is here interpreted to reflect uplift and erosion of the Derim Derim–Galiwinku LIP, rather than an influx of southern Musgrave sources. A new baddeleyite crystallisation age of 1,312.9 ± 0.7 Ma provides both a tight constraint on the age of this LIP, along with its associated magmatic uplift, as well as providing a minimum age constraint for Roper Group deposition. The unconformably overlying lower and upper Jamison sandstones are at least 300 million years younger than the Kyalla Formation and were sourced from the Musgrave Province. An up-section increase in isotopically juvenile compositions seen in these rocks is interpreted to document the progressive exhumation of the western Musgrave Province. The overlying Hayfield mudstone received detritus from both the Musgrave and Arunta regions, and its isotopic geochemistry reveals affinities with other early Neoproterozoic basins (e.g. Amadeus, Victoria and Officer basins), indicating the potential for inter-basin correlations.  相似文献   

关于山东省地热尾水回灌试验的应用研究   总被引：1，自引：0，他引：1       下载免费PDF全文

崔圆圆 《山东国土资源》2019,35(7)

为解决地热水开采利用过程中造成诸如水位下降、热流体排放引起的热污染和化学污染等问题,通过开展地热尾水回灌试验研究,认为在开采深层的地下热水资源的同时,必须进行人工的回灌补源,山东省通过在德州、东营、济南等地开展地热尾水回灌试验工作,效果显著。  相似文献   

山东蒙山与四川海螺沟冰川擦痕特征对比及成因分析   总被引：1，自引：0，他引：1       下载免费PDF全文

王照波  王江月 《山东国土资源》2019,35(6)

冰川擦痕在冰川遗迹的判断中具有极为重要的意义,其中以槽谷岩壁擦痕与冰碛砾石擦痕最为明显。槽谷岩壁擦痕具有细长密集、近似平行的特征;冰碛砾石擦痕具有短粗稀疏、方向杂乱的特征。除此之外,还有弧形擦痕、逆冲擦痕、新月形凿口、新月形裂纹、新月形裂口、颤痕等刻蚀遗迹的配套产出。经对比分析,蒙山发育的擦痕与四川海螺沟现代冰川谷内的擦痕具有完全的一致性,因此进一步确定了蒙山擦痕的冰川成因。  相似文献   

滕州荆泉水源地岩溶塌陷特征与成因分析          下载免费PDF全文

贾继成  孟宪洲  白平 《山东国土资源》2018,34(6)

自2015年6月以来,在山东滕州荆泉水源地范围内连续发生多起岩溶塌陷。通过研究区域地质条件,在已有认识的基础上分析得出发育的浅层开口岩溶洞隙的存在,一定厚度的松散覆盖层及地下水位大幅下降是该区产生岩溶塌陷的基本条件。阐述了岩溶塌陷形成发育过程及影响因素,得出长期过量抽采岩溶水是区内岩溶塌陷的主要因素,合理减少地下水开采量是预防岩溶塌陷最有效的方法。  相似文献   

鲁西地区矽卡岩型铜金矿He—Ar同位素测定及其地质意义——以沂南地区铜井式铜金矿为例          下载免费PDF全文

祝德成  田瑞聪  田京祥  于学峰  杨振毅  杨仕鹏 《山东国土资源》2018,34(8)

铜井式铜金矿(包括铜井铜金矿、金场铜金矿)是鲁西地区发现和开采最早、矿化最普遍的矽卡岩型铜金矿。该文通过矿床的He-Ar同位素测试分析,并结合前人的H,O,S,C稳定同位素分析和年代学测试结果,对铜井式铜金矿成因及成矿机制进行探讨。研究认为,铜井式金矿主要形成于燕山晚期(128~121Ma),黄铁矿中流体包裹体的~(3 )He/~(4 )He值为0.112 9~0.120 9R/Ra,高于地壳物质值,低于典型地幔物质值;~(40 )Ar/~(36 )Ar=364.1~458.0,高于大气值,低于地幔值,成矿流体中存在来源于地壳的放射成因Ar;~(4 )He/~(40 )Ar=1.16~3.433,平均2.296 5,略高于地幔值(1.36~2.23),低于典型地壳值(6.4),表明成矿流体中存在地幔He,Ar;同时有地壳He,Ar加入。综上认为,矿床成矿物质和流体具有深源特征,应来自地幔或下地壳,金成矿主要是与燕山晚期浅成—超浅成中酸性侵入岩有关,这些侵入体在侵位过程中与古生代碳酸盐岩地层发生接触交代作用,形成矽卡岩型铜金矿床。  相似文献