安徽霍山戴家河—六安毛坦厂地区中生代的火山作用

根据详细填图和研究资料,将区内中生代火山岩系划分为两个喷发旋回,分别属钙碱性系列和碱性系列,并对其岩石化学和地球化学特征等作了较系统的总结。查明了区内火山活动特点,恢复和圈定了数处火山机构,并对其喷发机制、演化规律进行了探讨。     

德尔布干成矿带火山岩型金(铜)矿床地质特征

近年来 ,在德尔布干成矿带发现了四五牧场金 (铜 )矿床 ,矿床地质特征显示成矿与晚侏罗世—早白垩世火山活动有关 ,今后应注意寻找此类型矿床     

松辽盆地庆深气田储层火山岩锆石U-Pb同位素年龄及其地质意义

庆深气田储层火山岩是由多期火山喷发叠置形成,分布在白垩系下统的营城组,以酸性喷发岩为主。火山岩离子探针(SHRIMP)锆石U-Pb年龄测定结果表明,储层火山岩年代集中在111～115 Ma,介于早白垩世晚期阿普第阶(Aptian)和阿尔布阶(Albian)的分界线附近。对比兴城与升平两个天然气产区的储层火山岩的形成年代,发现它们是同一时代的火山作用产物,并不是以前所认为的兴城地区火山岩属于营城组一段,升平地区火山岩属于营城组三段。这一结果对于松辽盆地火山岩气藏的勘探开发具有实际意义。     

松辽盆地改造残留的古火山机构与现代火山机构的类比分析

现代火山机构形态有盾状、锥状和穹状,可按喷发样式进一步划分为7种类型。据此分类,在松辽盆地周缘剖面及其北部徐家围子断陷区可识别出4类火山机构：盾状火山机构,由喷溢相熔岩组成,可夹有薄层爆发相火山碎屑岩;层火山机构,由互层的熔岩与火山碎屑岩组成,喷溢相与爆发相交替的序列明显;火山碎屑锥,几乎全部由火山碎屑（熔）岩组成,爆发相为主;熔岩穹丘由高粘度的流纹质、英安质熔岩堵塞火山口后缓慢挤出形成,喷溢相和侵出相发育,兼有火山通道相。盆地内埋藏火山机构最小坡度为3°,最大坡度为25°,底部直径为2～14 km,分布面积为4～50 km²,火山岩厚度为100～600 m;总体上呈现出数目多、个体规模小、受区域大断裂控制、具裂隙式-多中心喷发、彼此相互叠置的特征。火山岩岩性和岩相是控制松辽盆地古火山机构类型及形态的主要因素。     

火山岩相的岩屑识别——以松辽盆地南部东岭探区为例

以松辽盆地南部东岭探区为例,建立了用火山岩钻井岩屑来确定火山岩亚相的方法和工作流程。首先辨别真假岩屑,然后用真岩屑制片并进行薄片鉴定。根据火山岩显微镜下的岩性、结构和构造特征与火山岩岩相和亚相的对应关系确定其所对应的火山岩岩相和亚相。岩屑法对于厚度在一个采样间距（1 m）以上的火山岩层段可以准确定出火山岩亚相,与岩心鉴定结果的符合率大于90％。此外,该方法亦可校正录井岩性。用该方法对东岭地区15口探井火山岩段的录井岩性岩相进行了识别校正,提高了井间岩性岩相和储层对比的精度。     

松辽盆地东缘中生代断裂构造特征、形成期次及其储层意义

松辽盆地东缘中生代断裂构造十分发育。在对松辽盆地东缘营城组详细野外地质调查基础上,较系统刻画了断裂的性质、产状和时空分布规律,将研究区中生代断裂活动划分出海西晚期[CD1]印支期、营城期、营城末期和晚白垩世晚期4期。依据营城组火山口的分布规律首次识别出营城期隐伏断裂,该断裂控制了营城组火山岩的形成和分布。在研究区发现了营城期南北向断裂,为与徐家围子地区庆深气田营城组中的南北向断裂对比提供了重要依据。营城期本区处于近东西向伸展断陷和挤压逆冲相互交替的构造应力场中,营城末期受佳木斯-伊通和四平-哈尔滨两条左旋走滑断裂的强烈影响,形成北东-南西向的构造应力场,控制了北东向基性岩脉的侵入和大量北东向、北西向走滑断层的形成。认为研究区与徐家围子地区营城期及营城末期断裂具有明显的可比性,为庆深气田火山岩储层分布规律预测奠定了构造基础。     

Digital photogrammetry and kinematic GPS applied to the monitoring of Vulcano Island, Aeolian Arc, Italy

Digital photogrammetry and kinematic global positioning system (GPS) techniques are investigated and compared over a volcanic area as operational approaches to map the topography and monitor surface displacements. The use of terrestrial and airborne GPS to support the photogrammetric survey allowed for operational and processing time reduction without loss of accuracy. A digital elevation model (DEM) is obtained from the processing of the high-resolution digital imagery survey, which provides detailed information over a large area. The internal accuracy of the derived DEM has been verified by the comparison of two sets of data obtained from imagery acquired in different epochs; the observed root-mean-square error of residuals ranges from a few centimetres to 15 cm depending on the morphological features. Kinematic and pseudo-kinematic GPS surveys are performed to derive accurate 3-D coordinates at monumented benchmarks and accurate elevation profiles along footpaths. The average repeatability of the GPS measurements on benchmarks is 1 cm for measurement durations of 2–3 min. The standard deviation of interpolated vertical coordinates obtained at the crossings of kinematic GPS profiles is 4.3 cm. The high quality of these GPS coordinates justifies their use also for the validation of the photogrammetric DEM. A comparison of 6000 common points provides a standard deviation of residuals of 18 cm. The results show that the deformation pattern of a volcanic area can be rapidly and accurately monitored even in the absence of geodetic benchmarks. The integration of aerial photogrammetry with GPS kinematic surveys may be considered as an optimal approach for deriving high-resolution mapping products to be used in support of studies of volcanic dynamics.     

A study on neogene volcanic landforms of the middle Tanlu fault belt

Neogene volcanic group (also called Linchang volcanic group) in Shandong is mainly distributed in the fault basins of Linqu and Changle area, the west block of the Middle belt of Tanlu fault belt. Its formation is related to the huge strike-slip activities of Tanlu fault belt and the shrinkage of Bohai Sea basin[1]. It is the famous protected area of Shanwang paleontologic fossil in the world, and also the famous mining area of sappire and diatomite in the country. It is of important impli…     

宽甸火山群地质遗迹的地质特征与特殊性

宽甸地处营口-宽甸古隆起东部北缘,在距今0.12~8 Ma间,火山多次喷发留下了特殊的火山群地质遗迹.宽甸火山群的多期喷发,产生多种岩石组成的火山岩,火山岩中含有大量上地幔橄榄岩包体与丰富的巨晶矿物以及特殊的火山群地质地貌具有追溯地质历史的重大科学研究价值和观赏价值.