福建深沪湾海底古森林与全新世强古地震

介绍了深沪湾海底古森林遗迹，指出了海底古森林与古地震的关系，给出了深沪湾全新世强古地震的依据。     

福建深沪湾晚更新世古牡蛎滩与晚更新世中晚期以来的地壳运动

介绍了深沪湾沿岸地层、构造、海底古森林及晚更新世古牡蛎滩遗迹，深沪湾的地壳运动与古环境变迁；研究了海底古森林和晚更新世古牡蛎滩的成因。     

导致古森林沉没于海的福建深沪湾古地震研究

福建深沪湾海底古森林是强古地震遗迹。研究结果表明 ,全新世早期该处海底古森林生长在由松散的晚更新世含砾砂粘土构成的低凹洼地内。距今 70 0 0a左右的强古地震导致古森林沉没于海并形成泻湖环境 ,约距今 2 0 0 0a的又一次强古地震使海底古森林沉没到更深的海底 ,推测这两次古地震的震级都超过 7级     

导致古森林沉没于海的福建深沪湾古地震研究

福建深沪湾海底古森林是强古地震遗迹.研究结果表明,全新世早期该处海底古森林生长在由松散的晚更新世含砾砂粘土构成的低凹洼地内.距今7 000a左右的强古地震导致古森林沉没于海并形成泻湖环境,约距今2 000a的又一次强古地震使海底古森林沉没到更深的海底,推测这两次古地震的震级都超过7级.     

福建深沪湾海底古森林及晚更新世牡蛎滩遗迹介绍

福建深沪湾海底古森林及晚更新世牡蛎滩遗迹介绍徐起浩，冯炎基（广东省地震局，广州　５１００７０）（中国科学院广州地理研究所，广州５１００７０）福建深沪湾海底古森林及晚更新世牡蛎滩遗迹位于福建中部晋江半岛南东端深沪湾潮间带，是笔者等于１９８６年在执行国家     

福建晋江市前港湖、龙湖等四湖泊的成因机理

对前港湖、龙湖、虺湖、(氵丙)州湖的地理环境进行了实地考察,对钻孔和钻孔岩心沉积相及微体古生物进行了分析,对14C样品进行了年代测定,特别是通过对龙湖湖内和沿岸共78个钻孔岩心的分析,揭示了龙湖及沿岸残坡积层和晚更新世以来的沉积层展布,进而得到了龙湖成湖前的凹陷和发育在凹陷内的古河流环境,最终推断这4个湖泊为全新世晚期地震断塞湖.主要理由是:这4个湖沿衙口-(氵丙)州隐伏断裂(控制深沪湾地堑NW侧边界的断裂)呈线状展布,都为淡水湖;都发育在晚更新统含砾砂黏土及残坡积层构成的凹陷内,成湖前凹陷内有古河流;已发现龙湖湖盆SE近隐伏断裂处的下游古河床被抬高,且高出上游河床3m以上;前港湖、龙湖的最早成湖年龄都为距今2.4ka左右,这个年龄处于全新世晚期的强古地震发生的可能时间区间内,该地震同时导致了深沪湾海底古森林更深沉没于海底;都存在湖坝和可能的地震沉积相.推断上述湖泊是在该古地震时衙口-(氵丙)州断裂NW侧地块翘起掀升堵塞河流形成的地震断塞湖.湖泊形成后,当地盛行的风沙在湖坝处的加积和在地堑内的填积,导致湖坝变宽增高并和地堑沉积连成大致等高的一体,阻挡了湖水的外流,这是使湖泊继续发育并留存至今的重要原因.     

福建深沪湾地区晚更新世中晚期以来的地壳运动

研究表明 ,深沪湾地区晚更新世早中期地壳运动以下沉为主 ,沉积了冲洪积含砾砂粘土层。晚更新世中晚期以来地壳先升后降 ,近 15 0 0aB .P .以来地壳较为稳定。在 (2 5 5 80± 2 4 90 )～15 4 6 0aB .P .期间 ,该区地壳与水动型海平面大致同步升高 ,上升幅度为 8m左右 ,速率达 0 .78mm/a ,深沪湾内生长了古牡蛎。 15 4 6 0～ 110 0 0aB .P .期间 ,该区地壳快速上升 ,上升幅度超过 10m ,速率超过 2mm/a ,形成多个由晚更新世含砾砂粘土构成的低凹洼地 ,古牡蛎滩成为台地。其后地壳稳定 ,在低凹洼地内生长了古森林。 70 0 0aB .P .深沪湾发生了由强古地震导致的地壳快速下沉 ,古森林生长的凹陷洼地变成泻湖环境 ,古牡蛎滩台地与海面很接近。 2 0 0 0aB .P .左右 ,深沪湾又一次发生由强古地震导致的地壳快速下沉 ,古森林下沉到更深的海底 ,古牡蛎滩回到潮间带海域     

深沪湾海底古森林——牡蛎礁遗迹暨石圳海岸景观自然保护区论证会在晋江县召开

1990年9月26—28日在晋江县召开了建立福建省晋江县深沪湾海底古森林—牡蛎礁遗迹暨石圳海岸地貌地质景观自然保护区论证会。参加会议的有国家海洋局海洋第三研究所、海洋出版社、福建省科委、晋江县委、泉州科委及福建省有关高等学校、科研单位、地质、地震、林业等各部门的领导、专家、学者等总共51人,笔者被邀请参加了会议。     

青海省的古地震研究

本文根据近几年来在青海境内发掘的古地震资料,阐述了开展古地震研究工作的目的、意义和现状。提出了辨认古地震期次、判别古地震强度和确定震中位置的方法与标志。     

古地震学、地震复发性及面临的挑战

在过去25年中,地震地质学家和古地震学家们在确定单个古地震的时间和强度方面取得了重要信息。全球大部分地区,历史地震记录都短于地震轮回长度(发生一次会释放出某个地区长期累积的平均地震     

Ancient planets and cosmic vagabonds

Strange goings-on in space are revealed by powerful instruments in concert, observing the same phenomena at the same time and in consequence, revealing the inner workings of the stars. Peter Bond reports.     

Ancient solar wind in lunar microbreccias

The Apollo 11 soil breccias are samplers of the ancient lunar environment due to their history in the regolith and their efficient closure to addition of recent solar wind upon compaction. These breccias contain the lowest¹⁵N/¹⁴N isotopic ratio yet reported for any lunar sample (in fact, for any natural sample). This extends the range of variation of¹⁵N/¹⁴N of the solar wind to greater than 30%, from a δ¹⁵N of ?190‰ in the past to +120‰ at present. No mechanism is yet known that is capable of accounting for such a large change in the¹⁵N/¹⁴N ratio without producing a substantial concomitant change in the¹³C/¹²C ratio, although some sort of nuclear reaction in the sun appears to be required. Apollo 11 soil breccias and 15086 are all formed by meteoritic impacts which compact the lower regolith against the basement rock without much heating. Rock 15086 formed from the layer of regolith between 100 and 200 cm depth, as shown by the close agreement between the nitrogen content and isotopic ratios of 15086 and those of the Apollo 15 deep drill core. Cosmic ray exposure ages, based on spallation-produced¹⁵N, are 2.3 ± 0.4 b.y. for Apollo 11 breccias. This age is much greater than the estimate from cosmogenic²¹Ne, presumably due to diffusive loss of neon.     

Ancient volcanic glasses of the Urals

The existing data on findings of unaltered volcanic glasses in the Paleozoic (from Late Ordovician to Late Devonian inclusive) volcanic strata of the Ural fold belt are systematized. These glasses have compositions that correspond to tholeiitic basalts, potassic alkaline basaltoids, andesites, and rhyolites. Relic portions of glasses of cenotypal appearance are preserved in thick glassy crusts of pillow lava flows, in fragments among hyaloclastites, in bombs from tuffs, and in extrusive bodies and dykes. Chemical analysis showed that the amount of dissolved water was low (1–1.3 wt %) in the primary tholeiitic magma and higher (8–10 wt %) in the magma that formed island-arc hyalobasalts, potassic alkaline basaltoids, andesites and rhyolites.     

古建筑中灰土设计概述

采用的灰土抗压强度、抗剪试验方法,通过对相关古建筑中灰土材料的试验研究,来确定其相关物理力学性质指标和设计方法。并借用了岩石试验的相关试验方法,对灰土的相关物理力学性质进行了试验研究,试验最终确定了古建筑灰土主要的相关力学性质、参数。其成果和研究方法均作为其他古建筑检测、设计以及施工的参考。     

中国古籍中的地震海啸记录

2004年12月26日的印度洋地震海啸波及10国，造成20余万人死亡和失踪、50万人受伤、100万人流离失所的浩劫，引发了人们对海洋地震灾害的关注。建立海啸预警系统的呼声也日趋强烈。我国海岸线长达32000km，我国的经济重心又相对集中在沿海地区，产业发达，人烟稠密，人们自然会对海啸表示相当的关注。本文在查阅大量地震史料的基础上，发现我国也有地震海啸发生，但除台湾外，其他地区并不严重，概率较低。为防患于未然，对我国自身的地震预警系统也应适当予以关注。     

东昆仑断裂带古地震综合研究

整合多年来前人对东昆仑活动断裂带各段落古地震零散的现场考证结果,经过分析将其归并成68条独立的古地震事件及4条历史地震.根据功能原理,从理论上推导出断层段各震级档地震的约束关系.利用现代地震统计得到的区域地震活动性参数b、现场考证得到的各区段平均走滑速率、各震级档一次地震事件的平均位错量和破裂带长度,计算各段和全带不同震级档地震的平均复发周期,在此基础上讨论其地震活动规律.     

Ancient magnetic field determinations on selected chondritic meteorites

Paleofield intensity determinations involving a comparison of the stable natural remanence (NRM) component with a laboratory thermoremanence (TRM) were carried out on nine chondrites selected in Brecher and Fuhrman (1979a, this issue, hereafter called Paper I), as well as on two manifestly unsuitable controls. To judge their reliability: (1) heat-alteration was monitored by comparing saturation coercivity spectra before and after heating; and (2) the NRM and TRM intensity and stability were compared to those of residual magnetization following zero-field cooling (TRM₀) from above the Curie point of kamacite (Ni---Fe). The latter criterion separates the role of an external magnetic field (of 0.43 Oe) at cooling from intrinsic contributions to magnetic grain alignments, due to accretionary, metamorphic or shock-oriented petrofabrics.

In some chondrites (e.g., Brownfield, H3B; Holyoke, H4C; Farley, H5A), a surprisingly large (10% NRM) and stable TRM₀ proved so similar to NRM and TRM, that sizeable spurious “paleofields” — comparable to paleointensities obtained — were derived by the standard method for zero-field cooling. In other chondrites, with negligible TRM₀ (1% of NRM) and irregular AF demagnetization curves, more reliable paleofield strengths in the range 0.01–0.09 Oe were obtained (e.g., Cavour, H6C). These seem representative of magnetic fields at the end of metamorphism intervals (10⁷ years after accretion) and/or at post-shock cooling. Thus, field strengths obtained from ordinary chondrites are typically weaker (by factors of 10–100) than those reliably determined from carbonaceous chondrites and ureilites, suggesting temporal decay of nebular magnetic fields, from the end of accretion until the end of metamorphism and early catastrophic-collisional stages.