沂沭断裂带大水场剖面断层泥的ESR年代学研究

对山东省沂水县大水场断层剖面的断层泥带进行了野外观测和ESR 测年。断层泥的ESR年龄与由其穿插关系等判断出的断层活动次序相符。各断层泥的ESR 年龄显示出大水场断层经历了两个活动较频繁的时段,即0-25～0-28Ma B-P- 和0-45～0-55Ma B.P     

华北盆地北缘香河—皇庄断裂晚更新世以来活动性研究

香河—皇庄断裂位于华北盆地北缘,是京津唐地区一条重要的NE向断裂构造。浅层人工地震反射剖面探测发现,香河—皇庄断裂在廊坊市香河县西马家窝地区表现为一条NE－SW走向的NW倾正断层,剖面上呈铲状,上部略陡,向下逐渐变缓;其对大厂凹陷东缘没有明显的控制作用,为一条新近纪以来形成的断裂,切穿了前中生界基底,且第四纪以来仍有活动。通过部署于断层两侧的构造观察孔岩芯对比及测年数据判断,(6.69±5.6) ka以来香河—皇庄断裂无活动,其上断点很可能位于距地表15～30 m范围内,大致相当于晚更新世早期;在中更新世上部地层中,香河—皇庄断裂存在1.5～1.8 m的垂直落差。香河—皇庄断裂现阶段处于不活动状态,未来发生中强地震的可能性较低。     

潍坊市主要隐伏断层活动特征研究

利用浅层人工地震、电法勘探和工程钻探等多种方法在潍坊市开展了隐伏活断层探测工作,查明了潍坊市城区周围沂水-汤头断裂、鄌郚-葛沟断裂、寒亭断裂和潍县断裂等6条主要断裂的位置;通过释光(TL、OSL)和电子自旋测年(ESR)研究了这些断裂的最新活动时代。结果表明,潍坊市城区范围内无活动断层通过,为土地利用和城市建设规划提供了科学依据。     

用电子自旋共振（ESR）测年法测定断层活动年代的探讨

阐述了断层泥石英颗粒ＥＳＲ信号达到零化的温度和压力环境，通过４个具体ＥＳＲ测年实例，论述了测年样品的不同零化程度和测年数据的可靠性。对ＥＳＲ信号与ＴＬ（热释光）信号零化环境的差别及其原因进行了初步的探讨。介绍了断层测年样品ＥＳＲ信号达到零化的验证的方法。同时，提出了断层测年样品采集时应注意的有关问题     

Study on Buried Faults in the Weifang Urban Area

Buried faults in Weifang city and surrounding areas are studied with geophysical surveys such as shallow seismic survey and electrical exploration, and verified with engineering drilling. Six main faults are detected including the Yishul-Tangtou fault, Tangwu-Gegou fault, Hanting fault and Weixian fault, etc. The latest active age is determined by OSL, TL and ESR dating techniques. No active fault has been found so far in the Weifang urban area. Our results provide a scientific basis for land use and urban planning.     

ESR analysis of the Nojima fault gouge, Japan, from the DPRI 500 m borehole

Abstract Electron spin resonance (ESR) analyses of quartz grains in fault gouge were performed for a core sample taken from the Nojima Fault that moved during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake). Distribution of radiation-induced defects in the gouge at a depth of 389.4 m was measured by extracting quartz grains from seven discrete positions within 30 mm of the fault plane on the granite side. The decrease in E'₁ and Al centers was observed within 2 mm of the fault plane, suggesting partial annealing due to faulting. Partial annealing even at that depth suggested that conventional ESR dating, which is based on the hypothesis of complete annealing during faulting, was not applicable. Theoretical calculations of the temperature rise and of the thermal annealing of defects have been made by assuming a simple annealing model of heat generation on the fault plane. Thermal energy was calculated to have been approximately 8 MJ/m² to explain the profile of the heat-affected region. Thermal energy was much larger than the one estimated from hydrothermal solution, and corresponded to the frictional heat calculated for a normal stress of 20 MPa, a displacement of 2 m, and a frictional coefficient of 0.2.     

ESR and OSL dating of fossil-bearing deposits from Naracoorte Cave Complex palaeontological sites,south Australia

Little work has been undertaken on combined dating of sedimentary quartz grains using electron spin resonance (ESR) and optically stimulated luminescence (OSL) techniques in Australia. This study aims to assess the suitability of a combined ESR and OSL dating approach for establishing improved chronologies of Middle-Late Pleistocene deposits within the Naracoorte Cave Complex (NCC), South Australia. Here, we apply ESR and OSL dating in tandem to a series of samples collected from three different NCC sites: Whale Bone, Specimen and Alexandra cave. ESR quartz dating focuses on the multi-centre (MC) approach, which involves comparative evaluations of Al and Ti centre signals, while paired luminescence dating focuses on single-grain OSL analysis and includes examination of multi-grain averaging effects. The comparative ESR-OSL dating results exhibit broad agreement for deposits spanning 50–150 thousand years, with either the Ti–H or Al centre ages overlapping with paired OSL ages at 2σ in nearly all cases. MC ESR evaluations (Al v Ti–Li v Ti–H age assessments) indicate incomplete resetting of the bleachable Al centre signal for a small number of samples. Two-thirds of samples exhibit Ti–Li ages that are significantly older than corresponding Al centre ages, which is unexpected from a bleaching kinetics perspective and may indicate a broader reliability issue for Ti–Li palaeodose evaluation with these particular samples. Our findings: (i) support the applicability of both palaeodosimetric dating methods in this depositional setting; (ii) highlight the merits of applying combined ESR-OSL analyses in tandem, and; (iii) provide one of the first reliable evaluations of quartz ESR MC dating for samples with natural dose ranges as low as only a few tens of Gy. These results show that the Whale Bone, Specimen and Alexandra cave sites are temporally related and can be used to derive multi-site reconstructions of faunal assemblages and palaeoenvironmental history.     

深圳市观澜断裂第四纪活动性研究

观澜断裂是深圳陆域地区规模最大的北北西向断裂。通过地质地貌调查、联合钻孔探测及地质年代测定等技术方法对观澜断裂的第四纪活动性进行了详细考察与综合研究。结果表明：穿越低丘陵台地地貌区的观澜断裂两侧未见地貌差异或现代构造形变现象;4个典型地质露头和2条钻孔联合剖面显示断裂没有扰动上覆第四系．观澜大布巷钻孔探测剖面还获得了断裂上覆冲洪积砂层底部12．6±2．4Ka的光释光测年数据;断裂物质主要由碎裂岩、构造角砾岩、硅化岩等组成．可见硅质被膜及半固结岩屑或岩粉状物质;7个断层样品的电子自旋共振测试结果显示断裂的最新活动年龄为距今21．1±2．1万年。结合12条浅层地震测线探测未发现断裂错移第四纪覆盖层底界的事实．得出了观澜断裂最新一次活动发生在中更新世晚期．自晚更新世中期以后没有新的近地表活动的结论。     

Paramagnetic lattice defects in quartz for applications to ESR dating

Quartz is one of the minerals useful for ESR dating with many applications. Although the study has quite a long history since 1980's, ESR dating of quartz is still in a developing stage. After the basis in physics for the ESR signals in quartz is described, the current status of ESR dating of quartz is summarized for applications to fault gouge, tephra and sediment. Both basic studies for mechanisms and practical applications with independent age controls are still necessary to establish the protocols.     

深圳市横岗-罗湖断裂第四纪活动性研究

本文在前人研究的基础上,采用地质地貌调查、联合钻孔探测及地质年代测定等技术方法,对深圳横岗-罗湖断裂的第四纪活动性进行了详细考察与综合研究。结果表明：横岗-罗湖断裂最新一次活动发生在中更新世,自晚更新世中期以来没有新的活动证据。     

孝丰—三门湾断裂广德—杭州段第四纪活动性研究

孝丰—三门湾断裂是浙江地区一条规模较大的NW向断裂,该断裂与萧山—球川断裂交汇处曾发生929年杭州5 1/4级地震,与余姚—丽水断裂交汇处曾发生1998年嵊州—新昌4.5级地震。研究认为孝丰—三门湾断裂广德—杭州段大致以苏州—安吉断裂和湖州—临安断裂为界,分为广德—安吉段、安吉—黄湖段和黄湖—瓶窑段,活动性质为正断层,倾向NE。通过野外地质地貌调查和ESR年龄样品测年认为,该断裂最新活动时代为中更新世晚期。     

郯庐断裂带南段新活动性的初步研究

由于郯庐断裂带南段的第四纪地层不发育,尽管断裂构造岩松散而未固结成岩,也难以应用地层变位法来确定它的最新活动时代和活动方式。笔者在发育断层泥的断裂露头剖面上,采集断层泥样品9个,通过扫描电镜——石英碎砾刻蚀形貌法来确定它的新动活性。根据石英碎砾的刻蚀形貌类型判定断层的最新活动时代和活动方式;蠕滑?粘滑?从而确定郯庐断裂带南段的最新活动时代在N_2—Q_1或Q_2,活动方式以粘滑为主。     

临潼-长安断裂上断层崩积楔光释光测年的探讨

选择西安临潼-长安断裂带上韩峪乡范家村剖面的一个典型崩积楔样品进行测试.用3种不同的释光测试方法测出了9个不同的年龄数据.根据地层信息和矿物的释光生长曲线确定只有采用混合矿物简单多片再生法、纯石英矿物简单多片再生法以及纯石英矿物单片再生法的光释光测年法所得结果更接近于崩积楔的真实年龄.这些断层崩积楔年龄接近于围岩的形成...     

Microstructural features of fault gouges from Tianjing-shan-Xiangshan fault zone and their geological implications

Detailed observation of the microstructural features of 11 fault gouge and 3 fault breccia samples collected from Tianjingshan-Xiangshan fault zone has revealed that fault gouge can be classified into 3 types: flow banded granular gouge, foliated gouge and massive gouge. The determination of the shape preferred orientation (SPO) of survivor grains in fault gouges indicates that the foliated gouge displays a profound SPO inclined to the shear zone boundary, similar to theP-foliation; flow banded granular gouge displays a SPO parallel to the shear zone boundary, while massive fault gouge and fault breccia display a random SPO. All these fault gouges fall in different fields of shear rate ternary diagram.     

ESR dating of the Eupchon fault, South Korea

We investigated temporal pattern of Quaternary fault activity of the Eupchon fault zone in the southeastern part of the Korean peninsula, using ESR dating of fault rocks. The counterfeit E′ signal significantly affected the equivalent dose on some samples. In particular, the counterfeit E′ signal tends to affect samples with E′ intensity close to saturation level. Storage at room temperature for 360 days and heating at 170 °C for 15 min. after γ-ray irradiation did not change significantly the intensities, the dose responses and ESR ages for OHC, Al, and Ti signals. ESR ages from the Eupchon fault zone range from 2000 to 500 ka. The fault rocks were reactivated at least five times 2000, 1300, 900–1100, 700–800, and 500–600 ka ago. These data indicate that long-term cyclic fault activity of this fault zone continued into the Quaternary. The results from this study suggest that the Eupchon fault zone can be classified as a potentially active fault and presents some potential seismic hazards to the nuclear power plant in its vicinity.     

FAULT ACTIVITY OF THE SOUTHWESTERN SEGMENT OF THE EASTERN BRANCH OF XINYI-LIANJIANG FAULT ZONE IN GUANGDONG PROVINCE

The NE-trending Xinyi-Lianjiang fault zone is a tectonic belt, located in the interior of the Yunkai uplift in the west of Guangdong Province, clamping the Lianjiang synclinorium and consisting of the eastern branch and the western branch. The southwestern segment of the eastern branch of Xinyi-Lianjiang fault zone, about 34km long, extends from the north of Guanqiao, through Lianjiang, to the north of Hengshan. However, it is still unclear about whether the segment extends to Jiuzhoujiang alluvial plain or not, which is in the southwest of Hengshan. If it does, what is about its fault activity? According to ‘Catalogue of the Modern Earthquakes of China’, two moderately strong earthquakes with magnitude 6.0 and 6.5 struck the Lianjiang region in 1605 AD. So it is necessary to acquire the knowledge about the activity of the segment fault, which is probably the corresponding seismogenic structure of the two destructive earthquakes. And the study on the fault activity of the segment can boost the research on seismotectonics of moderately strong earthquakes in Southeast China. In order to obtain the understanding of the existence of the buried fault of the southwestern segment, shallow seismic exploration profiles and composite borehole sections have been conducted. The results indicate its existence. Two shallow seismic exploration profiles show that buried depth of the upper breakpoints and vertical throw of the buried fault are 60m and 4~7m(L5-1 and L5-2 segment, the Hengshan section), 85m and 5~8m(L5-3 segment), 73m and 3~5m(Tiantouzai section), respectively and all of them suggest the buried fault has offset the base of the Quaternary strata. Two composite borehole sections reveal that the depth of the upper breakpoints and vertical throws of the buried segment are about 66m and 7.5m(Hengshan section) and 75m and 5m(Tiantouzai section), respectively. The drilling geological section in Hengshan reveals that the width of the fault could be up to 27m. Chronology data of Quaternary strata in the two drilling sections, obtained by means of electron spin resonance(ESR), suggest that the latest activity age of the buried fault of the southwestern segment is from late of early Pleistocene(Tiantouzai section) to early stage of middle Pleistocene(Hengshan section). Slip rates, obtained by Hengshan section and Tiantouzai section, are 0.1mm/a and 0.013mm/a, respectively. As shown by the fault profile located in a bedrock exposed region in Shajing, there are at least two stages of fault gouge and near-horizontal striation on the fault surface, indicating that the latest activity of the southwestern segment is characterized by strike-slip movement. Chronology data suggest that the age of the gouge formed in the later stage is(348±49) ka.     

黄河小浪底水库区断层的ESR年龄测定

为了检验应用ESR方法测定断层运动年龄的可行性,在黄河小浪底水库区内的5个断层剖面上采集了13个样品进行ESR年龄测定。结果指出;研究区内的断层活动大致发生于距今0.154—0.183Ma及0.374—0.532Ma两个时期。并对一些有关问题作了讨论,指出这是一种很有希望的确定断层活动近似年龄的新方法,在地震地质及工程地质领域中具有良好的应用前景     

Potential of quartz OSL dating on moraine deposits from eastern Tibetan Plateau using SAR protocol

Optically stimulated luminescence (OSL) dating methods have been widely applied in Quaternary glaciology. However, glacigenic deposits are considered in general as problematic for OSL dating, mainly because they are transported shorter distances prior to burial and are usually partially bleached. Thus, most researchers choose glaciofluvial and glaciolacustrine sediments (with relatively longer transportation times) for OSL dating when constraining the age of glaciation. In this study, four samples were collected from a lateral moraine series at Zhuqing Village, northern margin of Queer Shan Mountain, eastern Tibetan Plateau, in order to investigate the applicability of OSL dating for morainic deposits. Quartz grains (38–63 μm) were extracted and measured using single aliquot regenerative-dose (SAR) protocol. Internal checks and dose recovery test show that the SAR protocol is appropriate for equivalent dose (D_e) determination. The effect of thermal transfer is small for all samples and the recycling ratio for each individual sample is close to unity. The symmetry in the D_e distributions indicates that quartz grains were well-bleached prior to burial. OSL ages show good agreement with geomorphological and field investigations, and are also concordant with an independent ESR age. It is concluded that: (a) the morainic deposits in Zhuqing were well-bleached and suitable for OSL dating; (b) SAR protocol can be applied to morainic deposits for samples under study.     

龙门山中段后山断裂带晚第四纪运动特征

本文通过对龙门山断裂带中段后山断裂带主要断裂的研究,认识到从茂汶断裂往西北到挂思岭断裂,断裂最新活动时代有逐渐变老的趋势,反映了龙门山后山断裂在晚新生代同样具有前展式(背驮式)逆冲推覆特征,主断裂茂汶断裂的最新活动时代为晚更新世晚期;后山断裂带除逆冲挤压构造变形外,还存在拉张变形,这为研究青藏高原的运动学及动力学等问题提供了重要信息.     

Luminescence and ESR dating of the sedimentary infill from the multi-level cave system of Alkerdi-Zelaieta (Navarre,N Spain)

The finding of Upper Paleolithic engravings in 2016 triggered a multidisciplinary investigation of the Alkerdi cave system (Urdazubi, N Spain). The study of the speleogenetic processes led to the identification of at least 6 paragenetic cave levels with associated sedimentary infill. In order to unravel the timing of changes in the karst dynamics and to get some insights about sediment origin, two sediment samples were collected from cave levels 4 and 1 for numerical dating purpose, using both Optically Stimulated Luminescence (OSL) and Electron Spin Resonance (ESR) methods. One additional modern-age sample was also taken from the entrance of the karst to evaluate the magnitude of the optical bleaching achieved by the quartz grains before entering the cave system. Last, one sample was collected from a flowstone for U-series dating, providing independent age control.OSL measurements were carried out using small quartz multi-grain (MG) and single-grain (SG) Single Aliquot Regenerative-dose (SAR) protocol. Initial Equivalent Dose (D_e) results show evidence of saturated OSL signal for the sample of the higher level (with ∼60% of saturated aliquots). Unlike SA data, SG analyses do not meet the usual quality criteria (e.g., relatively high recuperation ratios, only a few grains with useable signal), suggesting that corresponding dating results should be treated with caution.Hence, both MG and SG TT-OSL and MG ESR methods were subsequently employed, as the corresponding signals are known to have higher saturation levels than OSL ones. ESR analyses were based on the Multiple Centre (MC) approach using the standard multi-grain multi-aliquot additive (MAA) dose method, while TT-OSL measurements were performed following Demuro et al. (2020). The latter, however, did not return any useful results for both samples. MC ESR data show the usual D_e pattern (D_e(Al)>D_e(Ti op. D)>D_e(Ti–H)) indicating that among the three ESR signals analyzed, the Ti–H most likely provides the closest estimate to the true burial age. However, low measurement repeatability and goodness-of-of fit indicate that the reliability of the ESR results may be reasonably questioned.Results derived from this multi-technique dating approach provide the first chronological constraints for the sedimentary infill of the Alkerdi cave system. In particular, they suggest that sediment deposition in Cave Level 4 (ALK-OSL01) occurred around 130 ka, which is in good agreement with the minimum age constraint given by the speleothem (80.5 ± 9.0 ka). In comparison, the young age obtained for sample ALK-OSL02 (5.0 ± 0.9 ka) suggests recent Holocene formation of the lowest cave level 1.Finally, the MG De value obtained for the modern sample is close to zero (<1 Gy), indicating that the OSL signal is almost fully reset at a multi-grain level before entering the cave. Additionally, despite the large De overdispersion measured in this modern sample, the De values are one to two order of magnitude lower than those obtained with the same model in the other two samples. Therefore, the large OSL D_e overdispersion (OD) values of up to 64% obtained for the two samples from Cave Level 4 and 1 are most likely related to re-sedimentation processes inside the cave system.