生态环境地质学初探

针对当代地质学拓宽服务领域之要求,指出地质学、生物学、环境学交叉形成新的生长点——生态环境地质学。简述了生态环境地质学提出的科学依据、研究现状,提出了其存在问题和发展方向。     

四川盆地宣汉渡口和重庆北碚下三叠统海相碳酸盐碳同位素组成与演化

早三叠世海水的碳同位素组成与演化是二叠纪-三叠纪生物群体灭绝事件之后全球生态萧条与重建时期地球碳循环的重要记录,为地学界长期高度关注。文中测试了四川盆地宣汉渡口和重庆北碚下三叠统及相邻地层258个海相碳酸盐样品的碳、氧同位素组成,以便探讨早三叠世海水的碳同位素组成与演化。这些样品对海水碳同位素组成具有不同的保存性,飞仙关组及嘉陵江组第一、三段保存较好,而嘉陵江组第二、四段保存较差。基于氧同位素可以更为敏感地反映海相碳酸盐成岩蚀变性的原理,在碳、氧同位素相关性分析的基础上,以δ¹⁸O<-7.5‰为剔除标准,筛选出近200个有效数据建立了碳同位素演化曲线,该曲线与前人在贵州建立的同期曲线具有很好的可对比性。曲线显示出海水碳同位素组成的巨大波动,变化幅度达8.55‰,包括2个完整的上升-下降旋回,第1个旋回由飞仙关组和嘉陵江组第一段组成,第2个旋回由嘉陵江组第二段、第三段和部分第四段组成,同时还包括若干短周期的次级旋回。利用曲线形态与前人建立的同期曲线进行了岩石地层与年代地层单位的对比,飞仙关组可大致与Induan阶对应,嘉一段可大致与Smithian亚阶对应,嘉二段、嘉三段和嘉四段下部可大致Spathian亚阶对应;绿豆岩作为下-中三叠统界线其位置可能偏高,下-中三叠统界线应该位于绿豆岩之下的嘉四段内部。早三叠世海水碳同位素组成高频率大幅度的波动指示了生物大灭绝后环境的不稳定性,其中菌藻类等微生物灾后过度繁盛,可能导致了有机碳在短时间内的快速埋藏和海水碳同位素的正漂移;而碳同位素大规模的负漂移可能与甲烷水合物释放带来的轻碳有关。研究认为,白云岩所在的地层段往往具有更高的δ¹³C值,这可能说明微生物活动、白云岩形成和海水δ¹³C值升高之间的有机联系。下三叠统的白云岩、尤其是嘉二段和嘉四段的白云岩可能是微生物成因的,嘉陵江组有机碳的生产和埋藏可能主要是与白云岩形成有关的微生物的贡献,具最高δ¹³C值的嘉二段的烃类在一定程度上可能具有自生自储的特点。     

The first fossil mayfly nymph (Insecta: Ephemeroptera) from the British Isles

Mayflies are very rare in the British fossil record. The first nymph to be found, Schistonotorum wallisi gen. et sp. nov., is described from the non-marine Lower Cretaceous of southeast England. This Early Barremian find is from the Upper Weald Clay Formation at Smokejacks brickworks, Surrey. It is preserved as an adpression in concretionary sideritic ironstone from the upper insect bed exposed in the northeast face of the pit. The palaeoecological significance of this record is discussed.     

Resonance in rocks: Building a sustainable learning and engagement programme for the Jurassic Coast

World Heritage Sites have a duty, through educational and information programmes, to strengthen appreciation and respect by their peoples of the cultural and natural heritage of that site. The Jurassic Coast World Heritage Site (JCWHS) showcases nearly 185 million years of Earth’s history across 95 miles of coast and exemplifies some of the most spectacular rocks, fossils and landforms in the world. However, imparting these values to non-specialist audiences of all ages, abilities and needs provides unique challenges and opportunities. A critical factor for success in addressing such a wide audience is ensuring that content is relevant, meaningful and focused on the expectations of the end user. In this paper we present our learning framework that is based around two approaches. Firstly, we map out the needs and expectations of each of our four core audience groups and set out guidelines for who we should aim our content at and how that should be delivered. Secondly, we set out three pathways (Inspire, Curious and Motivated) through which a person may choose to engage with the Jurassic Coast. We argue that if our tailored content and experiences can resonate with a person at an emotional and intellectual level, they will ultimately become devoted to the Jurassic Coast. Through empowering a community of people who understand and appreciate the geoheritage of the Jurassic Coast, they can become advocates and champions for its protection and conservation in the future.     

Morphodynamique d'une dune sous-marine du détroit du pas de CalaisMorphodynamics of an undersea sandwave of the Dover Straits

This paper investigates the dynamics of sandwaves in relationship with tidal currents and weather conditions. The studied sandwaves are located in the Dover Straits and are covered by megaripples. These megaripples have migration speeds of $\text{1 }\text{m}\text{h}{}^{\mathrm{?1}}$ and slopes of 34°, suggesting the potential for avalanches to occur along the flanks of the sandwave. Tidal cycles without reversing currents were observed during stormy weather. Wind-induced currents lead to a unidirectional migration of megaripples and sandwaves. Well-defined areas without megaripples were observed and correlated with an increase in sandwave height. We propose interpretations for understanding sandwave saturation and migration. To cite this article: D. Idier et al., C. R. Geoscience 334 (2002) 1079–1085.     

Évolution récente et actuelle de la côte basque française (analyse et perspectives)

A recent multidisciplinary study, comprising existing data analysis and geomorphological and geological fieldwork, has helped clarify marine erosion processes of Pyrenean formations along the Basque Coast. An important discovery was made during our study of an alterite of regional extent, which calls into question recent and present evolution of the Basque Coast and the processes leading to coastline retreat. Modelling these factors has made it possible to propose a predictive scenario for future coastal evolution. To cite this article: A. Genna et al., C. R. Geoscience 337 (2005).     

气象条件对膨胀土力学参数的影响

由气象条件对膨胀土力学性质影响的分析,总结出土体气候影响带内土体力学性质基本变化规律。还对季节因素对工程地质勘察中力学参数选用的影响进行初步分析,提出相应解决方法。     

An overview of the geology and major ore deposits of Central Africa: Explanatory note for the 1:4,000,000 map “Geology and major ore deposits of Central Africa”

This paper is prepared within the frameworks of IGCP Project 470 and the associated BRGM scientific project “Africa 1999–2004” to accompany the 1:4,000,000 scale map “Geology and major ore deposits of Central Africa, presented at the 20th Colloquium of African Geology in Orleans in June 2004. It incorporates geological and metallogenic data from eight countries in Central Africa (Angola, Cameroon, Chad, Central African Republic, Congo Brazzaville, Democratic Republic of Congo (DRC), Equatorial Guinea and Zambia). The map is a harmonised and geo-referenced preliminary map, based on a GIS at 1:2,000,000 scale, and focusses on the spatial and temporal distribution of selected major deposits.     

关于地质调查立法研究

地质调查立法既是建设社会主义市场经济体制的需要,也是地质调查工作自身发展的必然要求,必须加快推进.地质调查工作提供公共产品,服务经济社会发展的方方面面,其立法应属于社会法领域.在“大国土”、“大资源”和“大地质”的理念下,地质调查工作隶属于自然科学体系的范畴,应该建立一个与资源平行的地质工作法律体系.在立法过程中,必须坚持地质调查工作的公益性定位,遵循地质工作规律、市场经济规律和法律工作规律,建立地质调查规划、地质调查权、成果质量监督检查、资料管理与服务、财政出资等6项基本制度,以保障和推动地质调查工作的发展.     

努力创造有宏观影响的大成果——中国区域地质志编纂的阶段性成果

中国区域地质志项目实施8年以来,已启动24个省级和2个区级地质志的编纂工作,其中11个省级地质志已经完成并通过验收,即将出版面世。通过编纂地质志,对编志地区以及全国地质进行了大综合、大集成,取得若干创新性成果:前寒武纪地质研究获重大突破;重新厘定了一些地区和全国地层系统;分析总结了岩浆岩时空分布规律;进行了构造区划,深化了中国地质构造的认识;发现典型的洋盆地层系统;成功进行了三维立体地质图的编图试点。志书的编纂完成,将为中国地质工作和国家经济社会发展提供一套具有宏观影响的基础地质系列丛书。