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《Proceedings of the Geologists' Association. Geologists' Association》2022,133(6):603-615
As mobile diamicton sediments move across already deposited sediments whether on land or into oceans generated by either glaciers/ice sheets or landslides, a series of soft-sediment deformation processes occur. These sediments carry signatures of processes at both macro- and micro scales. The processes occur across thin layers of sediment, it is at the microsedimentological scale that deformation structures are detected and is the subject of this paper. Examination of numerous diamicton thin sections of both known glacigenic and non-glacigenic sediments illustrate a myriad of microstructures. Microstructures can be subdivided into brittle, ductile, porewater induced and plasmic fabrics. These fabrics are part of a spectrum of development from grain stacks, to microshear to rotations and, in addition, domains are likely to occur due to scavenging and are all part of a repeating cycle of deformation as sediment is added, eroded, re-transported into the accumulating sediment pile. Diamictons can be subdivided into several levels of abundance of microstructure types from very common to rare to being absent. In general, other than ‘tile’ structures, all diamictons have all types of microstructures. A table is presented illustrating the differentiation of various type of diamictons in terms of microstructure type abundancies in relation to individual environments in which diamictons occur around the past margins of glaciated continents. A distinction can be successfully drawn that allows diamictons to be distinguished and differentiated. 相似文献
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通过黄河上游沙漠宽谷河段现场考察及实测资料分析,依据河岸物质来源及组成将黄河上游崩塌河岸划分为粘性河岸及非粘性风沙堆积河岸两大类,前者可分为平面崩塌、弧形滑动崩塌和复合式崩塌3种类型,后者表现出非粘性河岸的表层滑移及平面崩塌两种形式。进一步以磴口、乌海河段为例,分析粘性河岸和风沙堆积河岸的塌岸特征,并结合近10年的遥感影像解译分析河岸线崩退变化规律,揭示塌岸引起河道横向变化特征。结果表明粘性河段的塌岸后退距离大于风沙堆积河段,局部河段短期出现凹退凸淤的动态岸线变化特点,但全河段长期仍然处于总体淤积的态势。 相似文献
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根据围岩及成因不同,块状硫化物矿床可以分为火山成因块状硫化物矿床(VMS)型和沉积喷流(SEDEX)型.文章对两类矿床从宏观和微观地质构造特征上进行总结,以期对找矿勘探乃至确定矿床成因类型起一定指导作用. 相似文献
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根据关中平原黄土地层岩溶作用产物的研究,可将该区500～10ka BP黄土地层岩溶作用分为北亚热带侵蚀-溶蚀型、湿暖湿润带强溶蚀-侵蚀型、温冷半湿润带中溶蚀-侵蚀型和温冷半干旱带弱溶蚀-侵蚀型4种。根据古土壤发育时岩溶作用垂向分带遗迹,可将前人划分的渗流带进一步分为上部非饱和循环强溶蚀亚带、中部过饱和循环沉淀亚带和下部不稳定循环弱溶蚀-弱沉淀亚带。3个亚带的划分对确定CO_2在垂向上的循环有重要指示意义。该区500～10ka BP可分为10个岩溶发育阶段,构成5个岩溶旋回,发展趋势是由强变弱。 相似文献
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目前基于构件设计的基坑设计理论使得很多支护体系缺乏必要的冗余度,并导致了众多基坑事故。将离散元方法引入到基坑垮塌模拟和冗余度研究中,提出了基于局部破坏的冗余度分析模拟方法。进而以探究支撑端部连接对支护结构冗余度的影响为例,对两种连接情况的基坑的破坏过程进行了模拟,对其中的连续破坏现象进行了分析,并将模拟结果与实际工程进行了对比。结果表明,支护体系冗余度的提高可以有效地抵抗连续破坏的发生,防止基坑在局部损伤情况下,由一种形式的破坏引发其他形式的破坏,由局部破坏导致整体崩溃。另外,模拟结果也验证了离散元法在基坑破坏模拟中的适用性与可行性,为类似地下工程的破坏模拟和基坑冗余度的深入研究提供了参考。 相似文献
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冀中坳陷束鹿凹陷古近系沙河街组三段泥灰岩成因探讨 总被引：5，自引：3，他引：5
冀中坳陷束鹿凹陷中部古近系沙河街组三段下部（简称沙三下）泥灰岩属一类特殊的岩石类型组合，既非典型的碳酸盐岩，又非经典的碎屑岩。在进行了详细的岩心、薄片观察和各种分析化验资料的综合分析基础上，认识到研究区岩石为混积岩类，将混积岩（广义的）、混合沉积的概念和体系引入沉积物类型和岩相的划分中，为泥灰岩的科学定名提供了依据。据此对混积岩的类型进行了细致的划分，共划分出3大类型：结构混合、互层混合和夹层混合。每一类可以再细分为多种，其中结构混合包括①陆源组分为主的混积岩，②以内源组分为主的混积岩。互层混合成因的混积岩是最重要的岩石类型，本区所谓的纹层状泥晶灰岩大部分属于这一沉积类型，主要由灰质泥岩或泥灰岩与泥晶灰岩组成明暗相间的条带，有时含丰富的有机质。互层出现的形式是多种多样的，依据其岩石中原地组分和异地组分的含量不同，可进一步划分为4种类型。夹层混合沉积，表现为巨厚的碳酸盐岩质砾岩层夹前两类混积岩。构造、气候及物源等是控制混积岩形成的主要因素。 相似文献
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Basic Types and Structural Characteristics of Uplifts: An Overview of Sedimentary Basins in China 总被引：4，自引：2，他引：2
The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19-3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types ? the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can be subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones (belts) with multiple productive formations and various types of oil and gas reservoirs. 相似文献
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热力构造的概念分类特征及其研究进展 总被引：11，自引：0，他引：11
热力作用是与应力、重力相类同的一类地质作用力。以往对其研究多有忽视,近年来研究进展较大。热力作用是盆地发育演化和改造的主要因素,随着大陆动力学研究的深化,大陆垂向热力作用及其热力构造陆续被发现。对目前尚无公认统一分类方案的热力构造,根据现今构造、地貌形态分为三类:正向穹窿型、负向塌陷型和边隆核陷型;按岩浆-热力作用影响深度等分为五种类型:(古)地热异常群集区、表浅层火山喷发-热液活动-浅成斑岩侵入型、热力背斜(热穹隆)型、中深层侵入型(含壳内热柱型)、地幔热柱型。深度分类的第二类表浅层火山喷发-热液活动-浅成斑岩侵入型又可再分为许多亚类:火山-热力管道、环状断裂、破火山口和火山塌陷、中浅成侵入型(含变质核杂岩和浅层热穹隆)、隐伏热力构造。热力背斜(热穹隆型)实际为中成或中浅成岩浆侵入型;中深层侵入型多在盆地基底或中下地壳内活动或造山带内产出,可称为地壳热异常柱,在地壳内分布规模不大,盆地下部一般难以直接见到,要依靠地球化学、地球物理等技术手段来确认;岩浆岩体侵入的深度不一,热力构造类型和发育程度不同;地幔(或地壳)热柱型影响深度最大,没有明显的地貌显示,要依靠深部构造岩石学、地球物理学等间接研究方法确认。地质-地球物理-地球化学综合研究应该是一种有效的研究方法。盆地深部多层结构研究发现热力构造区多具有明显的垂向极低电阻率值区和壳内低阻层,应为地壳热异常柱,有其特殊的热力作用环境。盆地深部热力作用与热力构造的复杂性和较强烈活动性,对盆地能源研究与评价及煤油气铀成矿成藏的勘探评价等方面均具有重要的影响意义。 相似文献
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造盆作用及成矿盆地的历史动力综合分类建议 总被引：3，自引：0，他引：3
本文把历史分析方法与动力分析方法两种分折方法结合起来,提出了一个综合的盆地分类方案。按历史动力综合分类,造盆作用及盆地可划分为三大类:大洋壳型、雏陆壳(过渡壳)型及大陆壳型大壳型中可细分为活动区型及稳定区型。雏陆壳型包括前地槽型及地槽前期型。大陆壳型中计有地槽后期型、地台型和地洼型。 相似文献
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造盆作用及成矿盆地的历史──动力综合分类 总被引：5，自引：4，他引：5
陈国达 《大地构造与成矿学》1994,18(1):1-23
关于盆地的分类，不少学者提出过有意义的方案。它们主要是从某个单一角度进行：或者是从历史角度分析，或者是从动力角度分析，为了更较全面地认识它们，以求得更有效地指导找矿勘探，作者把两种分析方法结合起来，提出一个综合分类方案。按历史－动力综合分类，造盆作用及盆地可划分为三大类：大洋壳型、雏陆壳（过渡壳）型及大陆壳型。大洋壳型中可细分为活动区型（主要为拉张式）和稳定区型。雏陆壳型包括前地槽型（其中可分出多种活动区型及稳定区型，有待详究；活动区型中拉张式多见）及地槽前期型（主为拉张式）．大陆壳型中计有地槽后期（褶皱带）型（挤压式或拉张式）、地台型（主为陷落式，偶为张陷式－－断拉谷Ｑｕｌａｃｏｇｅｎ）和地洼型（挤压式、拉张式或压张式）。 相似文献
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The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19-3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types--the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can he subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones (belts) with multiple productive formations and various types of oil and gas reservoirs. 相似文献
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中国红土型金矿床研究综述 总被引：9，自引：1，他引：8
对红土型含矿床的勘查现状,矿化特征及成矿规律进行了探讨和总结,认为它形成于第三系－第四系红土风化壳内,可包括狭义的铁帽型金矿床,;概述了红土型金矿床的有效勘查方法和具体勘查方案。 相似文献
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试论新疆深部构造基本特征 总被引：4，自引：0，他引：4
在编制１：２００万新疆莫霍面等深线图的基础上，结合航磁、遥感、地质和地球物理资料，系统编制出新疆古深部构造分区图，划分出新疆深部构造类型和单元，并简要阐述其基本特征。深部构造类型分为构造区和幔源断裂，构造区分为幔隆区、幔坳区和幔坡区三大类及幔凸、幔脊、幔坪、幔槽、幔谷、幔凹、幔坡等若干工类，幔源断裂按其活动时间和特征分为古、恒、今幔源断裂三类。新疆深部构造单元划分为阿尔泰—蒙古幔坳区、准噶尔幔隆区、伊犁幔坳区、塔里木幔隆区、昆仑幔坡区和羌塘—冈底斯幔坡区等６个一级，２０个二级及２７个三级单元。由此对新疆古板块进行了初步探讨，认为额尔齐斯、天山中央、康西瓦三条断裂深部构造特征明显，可作为一级板块构造界线。准噶尔古板块属古生代洋壳板块，其内不存在前寒武纪变质岩结晶基底。 相似文献
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通过淮南煤田张集井田层滑构造的具体表现形式分析,对层滑构造进行了系统分类。根据层滑构造的表现形态分为揉皱型和断裂型两种基本类型,根据不同层滑构造的组合形态又可分为书斜式、垒堑式、阶梯状和"y"与反"y"字形等,并采用物理模拟方法对不同层滑构造类型进行了实验研究。运用镜质体的反射率各向异性恢复了矿区构造应力场,张集井田中生代以来至少受到两期构造应力场作用,NWW-SEE方向的拉伸是形成张集井田层滑构造的主要力学机制。 相似文献
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乌拉山金矿带金矿化分为石英脉型(Ⅰ),石英脉-蚀变岩型(Ⅱ),蚀变岩型(Ⅲ)三大类型,其分带性与大桦背花岗岩具有密切空间关系. 相似文献