CT 双期增强扫描在甲状腺腺瘤及结节性甲状腺肿鉴别诊断中的价值?          下载免费PDF全文

薛峰  孙丹  厉玛萱萱  乔忠云  单华 《CT理论与应用研究》2016,(4):471-476

目的：探讨 CT 双期增强扫描对甲状腺腺瘤和结节性甲状腺肿鉴别诊断中的价值。资料与方法：回顾性比较25例经手术后病理证实的甲状腺腺瘤和结节性甲状腺肿患者 CT 平扫及增强扫描结果,并进行分析。结果：25例患者共取出甲状腺结节35枚,其中甲状腺腺瘤18枚,结节性甲状腺肿17枚。腺瘤组平扫 CT 值30～60 HU,结节性甲状腺肿组平扫 CT 值25～55 HU,两者差别不明显。腺瘤组增强扫描 CT 值120～160 HU,结节性甲状腺肿组增强扫描 CT 值60～100 HU,两者有显著差异。结论：甲状腺 CT 双期增强扫描对甲状腺腺瘤和结节状甲状腺肿在鉴别诊断上可以提供重要的参考。  相似文献   

The Burren: a glacial,karstic and biokarstic expression of a limestone plateau in western Ireland          下载免费PDF全文

John P. McIlroy de la Rosa 《地球表面变化过程与地形》2016,41(11):1614-1628

The term glaciokarst describes a landscape where both glacial and karstic processes have contributed to geomorphological evolution and has been applied to a range of environments from the high arctic to the alpine Mediterranean. Nevertheless, glaciokarstic environments globally often exhibit significant variation in geomorphological processes and landforms due to these geographical differences. The Burren, County Clare, Republic of Ireland, is often quoted as a quintessential glaciokarstic landscape. However, the Burren and other similar environments would appear to lean towards one end of the glaciokarst spectrum, where solutional and biological processes have been dominant throughout the Holocene, in contrast to ice‐dominated glaciokarsts where karstic and biokarstic processes are temperature‐limited and cryospheric processes remain the principal geomorphological agents. Holocene landscape evolution and the development of a range of meso‐, micro‐ and nano‐scale karren features on limestone surfaces appears to be largely biokarstic in origin. Karstification of many glacially scoured limestone pavements would have begun under acidic soil cover, with biological soil processes contributing to smooth, rounded cryptokarstic surface forms. Holocene soil erosion is attributed to anthropogenic activity, climatic fluctuations and the evolution of the karstic groundwater system leading to vertical soil loss through widening grikes. Exposed limestone pavements subject to subaerial conditions often exhibit extensive lichen colonization which has been shown to influence the overall rate of karstification and contribute to the development of micro‐ and meso‐scale bioweathering features. Where cryptokarstic features have been exhumed from beneath soil cover, their evolution under subaerial conditions leads to intermediate, polygenetic karren features. In light of our current understanding of the Burren landscape, it is proposed that the term glaciobiokarstic may be a better expression to encompass the biological processes that have played a fundamental role in the evolution of the Burren and similar landscapes, without neglecting the contribution of glacial and inorganic karstic processes. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

对江苏沛县新庄铁矿区富水性规律的初步认识   总被引：2，自引：2，他引：0       下载免费PDF全文

景佳俊  陶文杰  管祯 《中国地质调查》2016,3(6):68-74

江苏沛县新庄铁矿属于典型的矽卡岩类接触交代型铁矿,矿区主要富水含水层为奥陶系灰岩。分析了该矿区地下水补径排条件、矿区含水层特征及断层富水性特征,初步总结了该矿区富水性规律。认为矿坑涌水主要受上覆灰岩控制,其次受构造断层控制; 断层的涌水量受裂隙充填影响变化较大,增加了突水、透水的风险性,将直接威胁矿山的生产安全。总结该矿区富水性规律,可为国内相同类型矿山的前期勘查及后期矿床开采提供参考。  相似文献   

安徽巢湖地区中二叠统栖霞组的遗迹化石特征及其沉积环境     

王冰  李双应  赵大千  石传军  杜叶龙 《地层学杂志》2012,(1):109-115

在安徽巢湖177高地、无为白牡山等地中二叠统栖霞组顶部灰岩段和臭灰岩段发现大量遗迹化石Zoophycos cf.caudagalli。这些遗迹化石以系统觅食迹为主,指示水动力及波浪作用较弱、贫氧的深水沉积环境。在栖霞组的砾状灰岩中,发现部分Zoophycos穿插于灰岩砾石和基质之中,这揭示栖霞组石灰砾岩中的砾石并非成岩作用成因,而是碎屑流沉积形成,属于异地成因碳酸盐岩。综合巢湖地区栖霞组的地层和岩石地球化学特征以及Zoophycos的生活习性和分布特征,发现表明巢湖地区中二叠统栖霞组臭灰岩段和顶部灰岩段属于贫氧的碳酸盐台缘斜坡沉积。  相似文献   

Differential Diagenesis of Limestone-Marl Alternations   总被引：1，自引：0，他引：1  

LIU Xiting  YAN Jiaxin  XUE Wuqiang 《地质论评》2012,58(4)

灰岩-泥灰岩韵律层包括结核状灰岩到灰岩和泥灰岩互层,广泛分布在陆棚及深海环境中,出现于各地质时期,是研究高分辨率地层学和环境恢复的理想工具.但是成岩作用在灰岩-泥灰岩韵律层形成过程中的作用一直存在分歧,有的学者认为差异化学压实成岩作用加强了原始沉积的差异,有的学者认为成岩作用不仅能够强烈歪曲原始环境特征,还可以通过自身成岩作用形成与原始沉积特征类似的现象.灰岩-泥灰岩韵律层中的差异成岩作用是指泥灰岩中的不稳定碳酸盐矿物在海底成岩环境中经过溶解、迁移和在灰岩中再沉淀,导致灰岩层没有明显被压实,而泥灰岩层受到明显压实.本文重点评述了差异成岩作用发生的环境和过程,并对与之相关的胶结物来源问题和有机质在早期成岩过程中的作用进行了讨论.并以华南中二叠统栖霞组韵律层为例,探讨了差异成岩作用在其形成过程中的作用,最后对以后的研究方向进行了展望.  相似文献   

Stratigraphic records of the dynamic uplift of the Emeishan large igneous province     

《International Geology Review》2012,54(1):112-130

Abstract

Fluid dynamical and numerical modelling predicts a large-scale regional domal uplift prior to basalt eruptions in large igneous provinces, which can be readily measured when a plume head rises below a shallow marine sedimentary basin. Research on the sedimentology, biostratigraphy, and isotopic chronology of the Emeishan large igneous province demonstrates that the sedimentary environment in the Maokou stage is not uniform carbonate platform facies, but rather sedimentary facies with a north–south linear alignment and west–east different distribution controlled by the syn-depositional normal faulting of the Changhai and Xiaojiang faults, which are the result of underwater dynamic uplift induced by deep mantle activity. The dynamic uplift started in the Maokou stage. Thus, thinning of the Maokou limestone was the product of the difference in the initial depositional thickness caused by the underwater uplift and post-depositional surface uplift and erosion, but post-depositional uplift was much less than kilometre scale. Sedimentary facies differentiation and tectonic–sedimentary evolution in the Maokou stage provide a constraint for the time of the initial eruption and eruption environment before and during the Emeishan basalt eruption. Small-scale magmatic activity might have already begun in the middle of the Maokou stage, whereas submarine and terrestrial sedimentary environments coexisted before and during Emeishan basalt eruption.  相似文献   

埋藏有机酸性流体对四川盆地东北部飞仙关组储层的溶蚀改造作用：溶解动力学实验研究   总被引：4，自引：0，他引：4  

黄康俊  王炜  鲍征宇  谢淑云  万能  梅廉夫  钱一雄 《地球化学》2011,40(3):289-300

通过白云岩化鲕粒灰岩与0.1 mol/L乙酸的旋转盘溶解动力学实验,研究了深埋藏中有机质热演化过程中伴生的有机酸对鲕粒灰岩储层的改造作用机理.结果显示,白云岩化鲕粒灰岩溶解反应的速率在3.26×10-7～6.66×10-7 mol/(cm2·s)之间,并且溶蚀速率随温度和转速的增加而增大.反应前后样品表面的扫描电子显微...  相似文献   

滇东南地区新发现中三叠统关岭组典型 台缘生物礁和斜坡滑塌灰岩     

黄志英  朱同兴  张启跃  周长勇  谢韬 《地质通报》2013,32(9):1436-1439

2012年底在云南省泸西县东山镇地区中三叠统关岭组中发现大规模典型台地边缘鲕粒浅滩和生物礁,同时在向阳乡方摆村附近发现典型台地前缘斜坡相泥晶灰岩,滑塌构造发育.台缘生物礁垂向3分结构明显,礁基为浅滩相鲕粒灰岩、豆粒灰岩;礁核为粘结海绵-水螅骨架岩,蓝绿藻粘结结构和亮晶栉壳状胶结结构发育;礁盖为台缘斜坡相深灰色薄层泥晶灰岩和泥质灰岩.生物礁横向展布也具有3个明显特征:礁后为碳酸盐台地相灰岩,礁核为粘结海绵-水螅骨架岩,礁前为台缘斜坡相薄层灰岩和泥岩,局部发育滑塌构造和滑塌角砾岩.该发现可为滇东南地区继续寻找油气资源开辟新的勘探方向.  相似文献   

Buruanga peninsula and Antique Range: Two contrasting terranes in Northwest Panay,Philippines featuring an arc–continent collision zone     

Lawrence R. Zamoras  Mary Grace A. Montes  Karlo L. Queaño  Edanjarlo J. Marquez  Carla B. Dimalanta  Jillian Aira S. Gabo  Graciano P. Yumul Jr. 《Island Arc》2008,17(4):443-457

Alternating chert–clastic sequences juxtaposed with limestone blocks, which are units typical of accretionary complexes, constitute the Buruanga peninsula. New lithostratigraphic units are proposed in this study: the Unidos Formation (Jurassic chert sequence), the Saboncogon Formation (Jurassic siliceous mudstone–terrigenous mudstone and quartz‐rich sandstone), the Gibon Formation (Jurassic(?) bedded pelagic limestone), the Libertad Metamorphics (Jurassic–Cretaceous slate, phyllite, and schist) and the Buruanga Formation (Pliocene–Pleistocene reefal limestone). The first three sedimentary sequences in the Buruanga peninsula show close affinity with the ocean plate stratigraphy of the North Palawan terrane in Busuanga Island: Lower–Middle Jurassic chert sequences overlain by Middle–Upper Jurassic clastics, juxtaposed with pelagic limestone. Moreover, the JR5–JR6 (Callovian to Oxfordian) siliceous mudstone of the Saboncogon Formation in the Buruanga peninsula correlates with the JR5–JR6 siliceous mudstone of the Guinlo Formation in the Middle Busuanga Belt. These findings suggest that the Buruanga peninsula may be part of the North Palawan terrane. The rocks of the Buruanga peninsula completely differ from the Middle Miocene basaltic to andesitic pyroclastic and lava flow deposits with reefal limestone and arkosic sandstone of the Antique Range. Thus, the previously suggested boundary between the Palawan microcontinental block and the Philippine Mobile Belt in the central Philippines, which is the suture zone between the Buruanga peninsula and the Antique Range, is confirmed. This boundary is similarly considered as the collision zone between them.  相似文献   

利用测井资料自动识别藻灰岩   总被引：3，自引：0，他引：3  

张振城  孙建孟  马建海  张炜  苏远大 《吉林大学学报(地球科学版)》2005,35(3):382-388

藻灰岩在测井曲线图上具有不同于其它岩性的特征,据此确定了7种测井参数(自然伽玛、自然电位、井径、声波时差、补偿中子、补偿密度及深电阻率),将测井数据归一化后得到了相应的岩性判别样本参数。利用F-Means中速度较快的聚类迭代(LBG)算法对研究样本进行分类,优选了一组数据用于判别分析。在进行Q因子分析的基础上建立了用于岩性判别的3个判别函数,并对花土沟油田某井段进行了岩性识别预测分析。  相似文献