松嫩平原土地沙化现状与动态变化   总被引：4，自引：2，他引：2  

张哲寰  赵海卿  李春霞  刘强  马宏伟  朱巍  张庭秀 《地质与资源》2008,17(3):202

松嫩平原沙地主要分布于松嫩平原的中西部地区,包括松嫩沙地和科尔沁沙地的一部分.沙地分布区处于半干旱地区,年降水量在350~450 mm,是松嫩平原生态环境变化的敏感地区.采用RS和GIS集成技术,对松嫩平原1986年和2001年的沙地进行遥感解译,结合野外调查,研究松嫩平原沙地分布的现状及其动态变化.结果表明,松嫩平原土地沙化有进一步发展的趋势,2001年沙地面积比1986年增加了861.1 km²,沙地平均每年以0.44%的速度扩展.其中,重度沙地变化率最大,中度沙地面积数量增加最多,轻度沙地略有减少.  相似文献   

CHARACTERISTICS OF THE T3-J1 RADIOLARIAN CHERT AND POTENTIAL FOR HYDROCARBON IN EASTERN HEILONGJIANG PROVINCE     

MA Jin-ping  ZHANG Ting-ting  XUE Lin-fu 《地质与资源》2008,17(4)

  相似文献   

陕西关中盆地中部地下热水H、O同位素交换 及其影响因素   总被引：4，自引：1，他引：3  

马致远  王心刚  苏艳  余娟 《地质通报》2008,27(6):888-894

对关中盆地地下热水δ＆18O和8D数据的研究表明：盆地中部西安、咸阳深部的地压地热流体发生明显的δ^18O同位素交换,并出现^2H同位素交换,表明热储流体发生了强烈的水岩反应,盆地周边及中部的非地压地热流体^18O交换则不明显。根据研究区^18O同位素的交换程度（用^2H过量参数d表征）和水化学资料,可将关中盆地热储流体分为循环型和封闭型热储流体2类。地热水埋深越大、滞留时间越长、TDS和温度越高、地质环境越封闭,18^O交换程度就越大。西安和咸阳地下热水分属于不同的地热系统,具有不同的补给来源。  相似文献   

冀东马兰峪背斜南翼与西部倾伏端盖层变形特征及其构造意义   总被引：2，自引：0，他引：2  

李海龙  张长厚  邹云  邓洪菱  马君 《地质通报》2008,27(10):1698-1708

燕山中部冀东遵化、迁西、青龙一带以太古宇深变质结晶岩系为核部的东西向构造形迹长期以来被认为是一个复式背斜构造,近年来又有学者提出它是一个中生代变质核杂岩。这2种不同认识涉及到华北克拉通北部中生代区域大地构造演化和稳定克拉通内部大型基底结晶岩系的剥露机制问题。对马兰峪背斜南翼和西部倾伏端盖层岩系开展的详细构造研究表明,变形总体表现为连续的褶皱变形及伴生的逆冲构造;构造样式表现为基底卷入式的厚皮构造与盖层内部软弱岩系控制的薄皮构造共存的特征;变形机制表现为顺层挤压导致的纵弯弯曲和相关的断裂构造;近南北向的缩短率介于16%～27%之间。盖层岩系中未发现变质核杂岩构造模型所预期的系列高角度正断层。基底与盖层不整合面接触带尽管在后期构造变形过程中曾经发生过局部的差异性滑动,但并不是造成大规模构造剥蚀和地壳柱切失的剥离断层。因此,冀东马兰峪背斜不是中生代的变质核杂岩,而是水平挤压背景下基底结晶岩系与盖层共同卷入纵弯褶皱变形的厚皮式褶皱构造。  相似文献   

应用生烃动力学法研究川东上二叠统烃源岩生烃史   总被引：3，自引：2，他引：1  

徐立恒  陈践发  卢双舫  马广宇  李吉君 《吉林大学学报(地球科学版)》2008,38(4)

现今川东上二叠统烃源岩生烃史研究具有局限性.首先,没有对上二叠统Ⅰ-Ⅱ1型灰岩生油、Ⅲ型泥岩的生气史分开评价;其次,海相镜质组反射率通过拟合公式换算成镜质体反射率评价烃源岩成熟度具有局限性.针对上述不足,笔者通过热模拟实验,利用化学动力学方法,标定出两类源岩生油、生气的动力学参数,并结合川东地区的埋藏史及热史,模拟出源岩有机质的成烃转化率曲线.研究表明:上二叠统灰岩、泥岩有机质在距今200 Ma和190 Ma分别进入了生油、生气门限,而在距今170 Ma和140 Ma生烃结束.  相似文献   

基于NSWT模极大值的PSF估计     

张亚新  耿则勋  陈波  马智刚 《测绘科学技术学报》2008,25(1):64-67

大气湍流扰动严重影响了空间目标的观测、成像和识别。在目标图像的重建过程中,对成像系统和大气条件先验知识的缺乏使PSF（Point Spread Function）的估计成为解决病态问题的重要内容。在NSWT（NonSubsampled Wavelet Transform）和Fried参数的理论基础上,根据不同尺度下小波变换模极大值和高斯点扩散函数方差的关系,结合Fried参数提出一种新的估计方法,即基于非抽取小波变换模极大值的PSF估计算法。实验结果证明,该估计算法是确实可行的,重建的PSF能够有效地改善因受大气湍流影响的图像解卷积的效果。  相似文献   

一种全自动提取居民地的方法     

王明孝  翟辉琴  马淑宇 《地理空间信息》2008,6(1):22-25

对遥感影像中居民地提取的各种方法作了一般性的阐述,并在吸收这些算法优势的同时,提出了一种全自动实现遥感影像中居民地目标的提取方法：先求取非最大值抑制后的梯度图,而后进行高斯模糊处理,以提高影像上居民地区域纹理特征一致性;通过增强大津法和形态学的方法全方位腐蚀与膨胀,完成面状地物居民地的提取;最后进行图象矢量化处理。论述方法的同时,展示和分析了实验结果。  相似文献   

On quality control of large scale aerial digital map citing Tongshan surveyed area as an example     

MA Zhong-wei  YANG Li-ping  HE Chao-jin 《地质学刊》2008,32(4)

  相似文献   

ELECTROCHEMICAL MEASUREMENT OF STEEL CORROSION IN SEABOTTOM SEDIMENT WITH “MD” METHOD     

马士德  李言涛  谢肖勃  郑国安  常伟  栗艳侠 《中国海洋湖沼学报》1996,(2)

The tbough one year cormsion potential and polarisation resistanoc for 3 kinds of stals in seabottomedment of Liaodong Bay were measured with the “MD” method.The measurements wiIl have some thoretical and pndital talues. The thooretical valoc lies in thatthe reoorded changing process of the practital corrosion case can be basis for indoor discussion andeectrochemical on the corrosion practical value lies in that the obtained datu canbe basis for designing and controlling elatrochemical protation syttems. In fact, it is very difficult tomeasure in situ the cornosion parnders of steeIs in sea sediment.  相似文献   

Provenance of Conglomerate and Sandstone from Early Permian Shoushangou Formation in Xi Ujimqin, Inner Mongolia: Implications for Understanding Paleo-Asian Ocean Subduction     

ZHANG Yingli  GUO Xianqing  MA Shouxian 《《地质学报》英文版》2024,98(1):10-31

During the Late Carboniferous to Early Permian, a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean (PAO) subduction in the Xi Ujimqin area. Nevertheless, the closure time of the PAO is still under debate. Thus, to identify the origin of the PAO, the geochemistry and U-Pb age of zircons were analyzed for the extra-large deep marine, polymict clastic boulders and sandstones in the Shoushangou Formation within the basin. The analyses revealed magmatic activity and tectonic evolution. The conglomerates include megaclasts of granite (298.8 ± 9.1?Ma) and granodiorite porphyry (297.1 ± 3.1?Ma), which were deposited by muddy debris flow. Results of this study demonstrated that the boulders of granitoids have the geochemistry of typical I-type granite, characterized by low Zr + Nb + Ce + Y and low Ga/Al values. The granitoid boulders were formed in island arc setting, indicating the presence of arc magmatism in the area that is composed of the Late Carboniferous to Early Permian subduction-related granitoid in southern Xi Ujimqin. Multiple diagrams for determining sedimentary provenance using major and trace elements indicate that Shoushangou sediments originated from continental island arc-related felsic rocks. Detrital zircon U-Pb age cluster of 330–280?Ma was obtained, indicating input from granite, ophiolite, Xilin Gol complex, and Carboniferous sources to the south. The basin was geographically developed behind the arc during the Early Permian period because the outcropped intrusive rocks in the Late Carboniferous to Early Permian form a volcanic arc. The comprehensive analyses of source areas suggest that Shoushangou sediments developed in a backarc basin in response to the northward subduction of the PAO. The backarc basin and intrusive rocks, in addition to previously published Late Carboniferous to Early Permian magmatic rocks of arc unit in Xilin Gol, confirm the presence of an Early Permian trench-arc-basin system in the region, represented by the Baolidao arc and Xi Ujimqin backarc basin. This study highlights the importance and potential of combined geochemical and geochronological studies of conglomerates and sandstone for reconstructing the geodynamic setting of a basin.  相似文献