Isotope geochronology is a newly developed science which combines geoscience, Physics, Chemistry and technical sciences, and it is a young and energetic branch of the earth system science. Based on the decay of radioactive isotopes, this science can determine the formation age of geological body and the age of geological events, aiming to study the formation history and evolution of earth and planetary materials. This paper presents brief introduction and summary of relative high-precise isotope dating methods in aspects of theory、experiment techniques、application scope、precautions for use, expecting to provide a useful reference to geologist. Involved isotope dating methods are U-Pb method、Ar-Ar method、 Rb-Sr method、Sm-Nd method、Re-Os method and（U-Th）/He method.（1）U-Pb method: It is one of the earliest radioactive methods for geological age determination as well as the most important isotope dating method in China so far. In the past 10 years, the introduction of insitu zircon U-Pb dating technique has played a significant role in promoting geological research in China, and its application is expanding.（2）Ar-Ar method: Ar-Ar dating has become one of the most important methods of isotope geochronology. The characteristics of this method are as follows: ① wide time-domain measurements, the oldest age is 3.8Ga (the age of lunar rocks), millennium age can be measured for the youngest age (eruption age of Mount Vesuvius, Italy); ② wide range of measurement object, in principle, all the k-bearing minerals and rocks can be used as Ar-Ar isotopic dating, even there are reports on successful determination of Ar-Ar ages from non-potassium minerals such as quartz、sphalerite which contain trace amounts of kainitite inclusion; ③Unique step heating technique and the management of Ar isotope correlation diagram of internal components can not only obtain high-precision age but unfold multi-stage geological evolution of the object; ④Joining with laser technique, it can be used to determine microzonation Ar-Ar age by search the minerals to be tested in polished section, so that we can obtain the priciest time information of the metamorphic rock P-T-t research; ⑤ wide application area, it is used in almost all the branches of geology; ⑥ the most important technique of deposit chronology; ⑦ the backbone technique of isotope thermochronology. Ar-Ar dating has its limitations: Firstly, the complex analysis leads to high cost and long cycle. Secondly, the accuracy of the determination of the neutron parameters directly affects the accuracy of dating samples. Nuclear recoil effect can result in high Ar-Ar age of very fine particles of clay minerals. As samples of Early Proterozoic and Archean metamorphic rocks, there may be natural K and Ar diffusion or later metamorphism, deformation and other disturbance, which will make it difficult for us to determine the age of early metamorphic events.（3）Rb-Sr method: It is a broadly applicated method. We can determine the isotope geological ages of intrusive rocks、volcanic rocks、metamorphic rocks and certain sedimentary rocks by using isochron technique. When determining the age of intermediate and acid intrusive rocks and volcanic rocks by using Rb-Sr isotopic system, if the rocks cooled rapidly, both the whole rock isochron and mineral isochron age may be the formation ages of the rocks. For metamorphic rocks, Rb-Sr isochron age generally represent the Sr isotope homogenization time when the latest strong thermal event happened. For sedimentary rocks, we can determine the authigenic mineral diagenesis age using Rb-Sr dating. The metal deposits, we can determine the formation ages of deposits using inclusion Rb-Sr isochron. Through Rb-Sr mineral dating to determine the formation of faults and ductile shear zone, we can limit the tectonic formation time. The biggest drawback of Rb-Sr dating is that, we may get wrong age due to the mobility of Rb which will result in an open system. In addition, we often face false isochrons problems.（4）Sm-Nd method: For Sm-Nd system is good at preservation and alteration and metamorphism resistance, ages from Sm-Nd dating can represent the original time when primary rocks formed and reflect the characteristics of diagenesis source material. For basic rocks、 ultrabasic rocks and for ancient rocks of Archean, Sm-Nd isochron dating method is a good method. Sm-Nd model age represent the time when the crustal rocks differentiated from CHUR mantle, using model ages of clastic sedimentary rocks, we can identify the source, the background of tectonic, the mean crustal residence age, and the formation and evolution history of crust. The disadvantage is the similarity of Sm, Nd geochemical properties, it will be difficult to separate from each other in the geologic process, and will result in narrow range of Sm, Nd ratio, which will make the Sm-Nd isochron dating problematic and even can not give reliable age.（5） Re-Os method: Re-Os isotope dating is the only mature method to determine mineralization ages of metal deposits directly. However, there are many problems in experiment techniques and applications: ① In recent years, some scientists find that the Re-Os ages of molybdenite in some metal deposits were higher than the ages of ore-bearing rocks, the reasons are unclear; ② the amount of Re in most sulfide mineral including pyrite is significantly low, and contains certain amount of common Os, this requires very low background in the process of chemical preparation of samples, which makes it difficult for general laboratory to achieve, and the common Os is difficult to deduct; ③ sometimes, post hydrothermal activities may reset Os isotope, therefore, the closure temperature and influencting factors of the metal sulfide Re-Os isotope system is a pressing problem to be solved.（6） (U-Th) / He method: The advantage of (U-Th) / He isotope system is that its closure temperature is the lowest among the existing isotopic systems, and it can record temperature information and the time when geologic body went through a lower temperature process. The method also has considerable application in the deposits chronology. The disadvantage is that as the closure temperature is very low, we should pay special attention to the cooling rate and effects of re-heating in geological dating.

同位素地质年代学是地球科学、物理学、化学和技术科学相互交叉发展起来的一门新兴学科，是地球系统科学中一个年轻而充满活力的分支学科。它根据放射性同位素衰变规律确定地质体形成和地质事件发生的时代，以研究地球和行星物质的形成历史和演化规律。本文对几种常用的精度比较高的同位素测年方法从理论、实验技术、应用范围、使用的注意事项等方面予以简要总结和介绍，期望为地质同行们提供有益的参考。所涉及的同位素测年方法主要有U-Pb法、Ar-Ar法、Rb-Sr法、Sm-Nd法、Re-Os法、（U-Th）/He法等。（1）U-Pb法：是最早用来测定地质年龄的放射性方法之一,也是国内目前最重要的同位素测年方法。近10年来，近乎完美的锆石微区U-Pb年龄测定技术的引进对我国的地质科学研究起到了巨大的推动作用，并且其应用领域仍在进一步扩展中。（2）Ar-Ar法：Ar-Ar同位素地质测年方法已经成为同位素地质年代学研究最主要的方法之一。该方法具有以下特点：①测量的时间域较宽，最老可到38亿年（月岩年龄），最年轻可测到千年级（意大利维苏威火山喷发年龄）；②测量对象广泛，原则上，所有的含钾矿物、岩石都可以用作Ar-Ar法同位素测年，甚至含有微量钾盐包裹体的非钾矿物如石英、闪锌矿等也有成功测定出Ar-Ar年龄的报道；③独特的分步加热技术和内部组分的Ar同位素相关图处理技术不仅可以获得高精度的年龄，还可以揭示被测定对象所经历的多期地质演化信息；④和激光技术配套可以直接在岩石光片上寻找待测矿物进行微区（几十微米－几百微米）Ar-Ar测年，从而能够获得变质岩P-T-t轨迹研究中最精确的时间信息；⑤应用领域广泛，几乎所有的地质学分支学科中都有应用；⑥是矿床年代学研究的最主要的技术手段；⑦是同位素热年代学研究的支柱技术。Ar-Ar法测年也有其局限性：首先是分析技术复杂导致其成本高、分析周期长。其次中子参数测定的准确性直接影响样品年龄测定的准确性。核反冲效应会导致极细粒的粘土矿物Ar-Ar年龄结果偏高。对于早元古代和太古代古老变质岩样品，由于可能存在K和Ar的自然扩散作用或后期变质、变形等多因素的扰动作用，用Ar-Ar法很难测出早期的变质事件年龄。（3）Rb-Sr法：是一个应用很广泛的方法，利用等时线技术可以测定侵入岩、火山岩、变质岩和某些沉积岩的同位素地质年龄。在用Rb-Sr同位素系统测定中酸性侵入岩和火山岩的年龄时，如果岩石迅速冷却，无论用全岩等时线法或矿物等时线法得到的年龄都可能是岩石的形成年龄。对于变质岩，矿物Rb-Sr等时线年龄一般代表岩石遭受最后一次强变质热事件Sr同位素均一化时间。对于沉积岩，可以利用Rb-Sr法测定成岩自生矿物年龄。对于金属矿床，可以用包裹体的Rb-Sr等时线确定矿床的形成时间。通过断层和韧性剪切带形成的矿物的Rb-Sr年龄测定，可以限定构造形成时间。Rb-Sr法最大缺点是，由于Rb的流动性，极易形成开放系统，从而得到不正确的年龄。此外，还还经常受到假等时线的困扰。（4）Sm-Nd法：由于Sm-Nd体系的保存性能良好,抗蚀变和变质作用的能力较强,因此Sm-Nd法年龄能代表原岩生成的时间和反映成岩物质源区的特性。对于基性岩、超基性岩，对太古宙古老岩石，Sm-Nd等时线法是较好的测年方法。Sm-Nd模式年龄代表地壳岩石从CHUR地幔源中分异出来的时间，利用碎屑沉积岩的模式年龄可以鉴别沉积物的源区，判断岩石形成构造背景，了解其物源区存留地壳的平均年龄，揭示地壳形成和演化历史等。其缺点是由于Sm、Nd地球化学性质的类似，地质作用过程中难以发生相互分离，Sm、Nd在岩石中的比值变化范围就很小，给Sm-Nd等时线法测年带来了困扰，有时不能给出正确可信的年龄。（5）Re-Os法：Re-Os同位素测年法是目前能够直接测定金属矿床矿化年龄的唯一成熟方法。但在实验技术和应用方面还存在不少问题：①近年来发现有些金属矿床辉钼矿的Re-Os年龄高于其赋矿围岩的年龄，原因不明；②黄铁矿等多数硫化物矿物含Re量很低，并含有一定程度的普通Os，对样品化学制备过程中低本底的要求很高，一般实验室难以达到，普通Os也难以准确扣除；③后期的热液活动有时可以使Os同位素发生重置，因此，金属硫化物Re-Os同位素体系封闭温度及其影响因素是一个亟待解决的问题。（6）（U-Th）/He法：(U-Th)/He同位素系统的优势是其封闭温度是已有同位素体系中最低的，能够记录地质体经历较低温度范围的时代与温度信息。该方法在矿床年代学研究中也具有可观应用前景。其不足之处是因为封闭温度很低，在用于地质体定年时要特别关注冷却速率和再加热作用的影响。

河南平顶山地区朱砂洞组是华北 陆块南部下寒武统底部辛集组之后沉积的珍贵地质遗迹。通过对朱砂洞组的命名、沿革的调查及其地层学、岩石学、沉积学、层序地层学、古生物学及含矿性研究, 确认朱砂洞组属于典型的大区级地质遗迹,具有较高的科学价值,值得保护。通过对大地构造分析,对朱砂洞组形成的地质背景提出新认识。朱砂洞组形成时大地构 造格局是陆在北,海在南,海水来自与扬子浅海相连的北秦岭二郎坪海槽。早寒武世早期扬子海向北侵进,通过南襄海峡,贯通二郎坪海槽,于沧浪铺期到达华北陆 块南部,成为华北陆表海,在浅水陆棚及滨岸潮坪相辛集组形成之后,成为滨岸潮坪缓坡与浅水潮下缓坡,生成朱砂洞组滨岸潮坪相含膏岩系。

Seismites of the Shidian Member of the Cambrian Mantou Formation have been found in different areas of the central Shandong Province in recent years. They were formed in a dry tidal flat lagoon environment, and developed in the upper part of the Lower Cambrian. They have the characteristics of intra-layer structures recording strong seismic events, such as the escaped structure of water (seismogenic micrite vein) , liquefied fold deformation, micro-fault-graded and net-like cracks etc. Through a comprehensive correlation of the strata, the isochroneity of seiemites in different areas is proved in the paper. It is considered that there was a seismic active period at the end of the Early Cambrian in the central Shandong area. The seismic sequence belongs to the original position system of the vibrational liquefaction seismic sequence in carbonate rocks put forward by Qiao Xiufu(1994, 2001a), and the distribution of the seismites was in a region of earthquake intensity of 7-11 degree caused by some strong palaeo-earthquakes about 510 Ma ago, with the palaeo-Tancheng-Lujiang fault zone as the seismic center. In order to be distinguished from the seismic event bed of the Neoproterozoic Shiwangzhuang Period in the central Shandong area, this earthquake-genetic stratum is temporarily named the seismic event bed of the Mantou Period.

近几年在鲁中不同地区发现馒头组石店段中均有震积岩产出。震积岩形成于干燥的潮坪泻湖环境，发育在下寒武统的上部。它们具有记录强地震事件的泄水构造（地震成因泥晶脉）、液化卷曲变形、阶梯状小断裂、层内错断和液化网状裂纹等层内构造的特征。本文通过地层综合对比，论证了不同地区震积岩的等时性。认为：鲁中早寒武世末有一个地震活跃期；地震序列属乔秀夫（1994，2001a)提出的碳酸盐岩振动液化地震序列的原地系统；震积岩分布范围是约在510Ma前，以古郯庐带为震中的强地震之7－11度烈度区。为区别于张增奇（1996）提出的鲁中新元古代石旺庄期地震事件层，将此地震成因地层名之为馒头期地震事件层。

早寒武世初期,随着从古沂沭海 峡向西海侵的发展,鲁西地区沉积了厚度不等的主要由砂岩、泥岩和碳酸盐岩组成的滨海、潟湖及浅海相沉积,其层位属下寒武统底部的李官组和朱砂洞组。在它们 沉积过程中,沂沭断裂带正发生着伴有频繁海底地震的构造裂陷活动,使海底沉积物在自沂沭断裂带向西200 km范围内产生了不同的地震效应,形成了各种地震成因的同沉积变形构造。发育在朱砂洞组中的地震效应记录除有少量半固结沉积物的脆性变形外,主要是液化底 劈、碳酸盐灰泥火山、液化脉、液化角砾岩、震褶曲、粒序断层和硅质脉等软沉积物变形;李官组中既有含滑塌褶曲、负载构造、球—枕构造等震滑塌堆积,也有震 浊积岩。由海底地震效应记录所反映的震级为5～8.9级。这些证据表明沂沭断裂带在早寒武世初期发生了强构造活动。从海底工程地质的角度来分析,上述地震 效应是地震对海底沉积层的破坏形式,这为认识海底工程地基岩土层的地震破坏提供了直观的资料。

新疆大石头-色皮口地区位于博格达造山带东段北部。该区大石头群流纹岩Rb-Sr同位素等时线年龄为306．7±2．3Ma，是博格达裂谷闭合后区域隆升阶段的产物。这些流纹岩的εNd（t）为＋5．30～＋6．40，（^87Sr／^86Sr）；为0．703289～0．703496，（^206Pb／^204Pb），为18．037～18．425、（^207Pb／^204Pb），为15．524～15．567、（^208Pb／^204Pb）；为37．198～37．810，因此其Nd-Sr—Pb同位素特征与博格达陆内裂谷伸展和沉降阶段形成的早石炭世七角井组玄武岩和流纹岩相近。七角井组与大量玄武岩伴生的少量流纹岩是由玄武岩浆分离结晶作用的产物，而大石头群中的大量流纹岩群仅与少量玄武岩伴生故是由玄武岩浆分离结晶的产物可排除大的可能性。该区流纹岩很可能是碰撞后的底侵玄武岩在地幔热量影响下发生重熔的产物。大石头群流纹岩正εNd（t）值、负εSr（t）值（低Sr初始值）和低Pb同位素比值表明博格达裂谷碰撞后的底侵幔源岩浆重熔的基性产物与碰撞前的七角井组玄武岩一样也来自亏损地幔。

在对苏皖北部的上前寒武系进行了矿物学研究基础上,选择安徽北部淮南群四顶山组燧石作为测定对象,系统测试Rb-Sr和Sm-Nd同位素,应用Sm-Nd等时线方法进行了定年.本次研究表明,安徽淮南群四顶山组燧石可能是在海洋环境中形成,主要反映了陆源物质特征,其形成时代约为800Ma.这为苏皖北部地区上前寒武系是位于华北区青白口系和扬子区震旦系之间的一套地层提供了一个新的证据,也进一步印证了淮南生物群属于先伊迪卡拉期的学术观点.

The well known geological mountainMantoushan is located in the mountain area of southern Jinan city. The standard (stratotype) profile from the Longwangmiao Stage to the Zhangxia Stage of the Lower middle Cambrian of the North China is established here. Here, geological traces are so rich and research history is so long that Mantoushan mount is famous at home and abroad. The Jinan area lies in the west side of  the Tanlu fault and seismic zone. During the early Cambrian, a set of terrigenous clastic sediments consisted of sand and mud intercalated with carbonate were deposited in the western Shandong region including Jinan city where was littoral, sabkha and epicontinental sea, which stratigraphic sequence, from bottom to top, was the Liguan Formation (∈ 1 l), the Zhushadong Formation((∈ 1 l) and the Mantou Formation(∈ 1-2 m).   By means of field observation and labexammination, various synsedimentary deformation structures caused by earthquakes, namely seismites, were identified in the Lower Cambrian of Mantoushan mount, eastern hill to the Qingyang village, Hongyegu valley and Gunqiushan mount, and so on. The synsedimentary deformation structures discovered by the study include convolute deformation (seismic fold), graded microfault, gliding structure, slump fold, load structure, pillow mass, mixed insertion sediment, soft siliceous vein, diapir structures of soft siliceous layers, deformation of diatoms stramatolitic, settlement structure, thixotropic wedge, boudinage, seismic crack or fissure, shattered breccia and seismic breccia, and so on. Most of them belong to plastic deformation structures of softsediments, but shattered breccia, seismic breccia and seismic crack or fissure are brittle deformation structures of semiconsolidated to uncompletely consolidated sediments. Their characteristics and formation mechanism are detailed in this paper.   The thixotropic wedge has been reported firstly in China. Some thixotropic wedge and settlement structures developed in dolomite with siliceous layers, and their original sediment was dolomitic limemud with soft siliceous layers. By triggering of strong earthquake, soft siliceous layers became more soft because viscosity of siliceous sediment (SiO 2 · n H 2 O) get diminished, meanwhile dolomitic limemud was liquefied.   Under vertical shock force, soft siliceous layers were cut off, and subsequently sinkage of disconnected siliceous layers formed settlement structure, which extended down so that disconnected siliceous layers converged to result in the formation of thixotropic wedge.   Differences of thixotropic wedge, seismic crack and filling structure of seismic crack are as follows: (1) Thixotropic wedge are one of plastic deformations which are formed for viscosity of soft nonliquefied sediments is diminished and their rheological property is enhanced (thixotropy) by earthquake triggering. With settlement structure  going on to deep, thixotropic wedge was formed. Formations of wedge body and it's host rock are synchronous; (2) Seismic crack is a tensile fissure of the "V" shape，which belongs to brittle deformation of semiconsolidated or incompletely consolidated sediment formed by the earthquake action; (3)The filling structure of seismic crack is usually wedge yet, but its filling is soft sediment or brittle seismic breccia. In general, the formation process of wedge body is out of synch with that of the crack.   On the basis of the distribution of palaeotectonic plates and seismic zones in the early Cambrian, it is considered that these seismic sedimentary traces are records of the intraplate ancient earthquakes during the early Cambrian, and it is can be deduced that they are response to tectonic activities of the PaleoTanlu fault zone. The discovery of paleoseismic event records and the interpretation of this paper enrich the geological sciences connotation of the southern Jinan area, especially the Mantoushan mount. 

蜚声中外的地质名山馒头山处在济南南部山区。通过野外调查和室内研究，从馒头山及其附近的青杨村东山、红叶谷、滚球山等地的下寒武统中，鉴别出了许多地震引起的同沉积变形构造（震积岩），主要有卷曲变形（震褶岩）、粒序微断层、滑移构造、滑塌褶曲、负载构造、枕状体、混插沉积、软硅质脉、软硅质层底辟构造、硅藻叠层石变形、沉陷构造、触变楔、布丁、震裂缝、震裂角砾岩及震碎角砾岩等。本文较详细地阐述了它们的特征和形成机理。触变楔属国内首次发现。触变楔和沉陷构造发育在夹软硅质层的白云岩中，其原始沉积物是含软硅质层的白云质灰泥。受强震触动，因软硅质沉积物(SiO2·nH2O)的粘度变小，软硅质层的粘度变小而变得更软，灰泥同时发生液化；在竖向震动力作用下，软硅质层被断开、继而沉陷形成了沉陷构造；沉陷构造向下延伸，结果使断开的硅质层汇聚，形成了触变楔。根据早寒武世古构造板块与地震带的分布，认为这些地震沉积遗迹是早寒武世板内地震记录，推测由古郯庐带的构造活动的响应。这些古地震事件记录的发现，丰富了济南南部山区、尤其是馒头山的地质科学内涵。 