吉林省东部贵金属、有色金属矿床的时空分布规律

将吉林省东部地区的贵金属、有色金属矿床在成矿作用时间上与全球性成矿事件及区域性成矿事件对比分析,总结成矿的相似性和本区成矿的特点及具中国特色的燕山期成矿的重要性,提出区内大型矿田(或矿集区)的空间分布特点及主控因素,对成矿预测具指导意义。     

丹霞地貌概念讨论

关于丹霞地貌概念上的不同意见,主要是：①岩性岩相上是较单一的“陆相碎屑岩”还是涵盖多种岩性岩相的“沉积岩”;②地貌上是“丹崖”,还是“赤壁丹崖”,或是“赤壁丹崖群”。根据目前已知的中外丹霞地貌的基本特征,初步认为,丹霞地貌是由砂岩砾岩为主的沉积岩经侵蚀作用所形成的赤壁丹崖群地貌。近10a来,一些丹霞地貌概念,基本上属于“中国丹霞地貌”的概念,不完全符合世界丹霞地貌的实际情况。     

Early Cretaceous sedimentary provenance and structural evolution of the central Sanandaj–Sirjan Zone,Iran: implications for palaeogeographic reconstructions of the northern Neo-Tethyan margin

ABSTRACT

The Early Cretaceous was an important epoch in the evolution of the Earth system in which major tectonic episodes occurred, especially along the Alpine–Himalayan belt. The paucity of reliable palaeogeographic data from the central segment of this geological puzzle, however, hampers the reconstruction of a panoramic view of its Early Cretaceous palaeogeography and geodynamic setting. Here we present multidisciplinary provenance data from Lower Cretaceous strata of the overriding plate of the Neo-Tethyan subduction zone (the Sanandaj–Sirjan Zone; SSZ, of central Iran), including structural, basin-fill evolution, petrographic and geochemical analyses. Sandstone provenance analysis of Lower Cretaceous red beds suggests the occurrence of sub-mature litho-quartzose sandstones attributed to an active continental arc margin in convergent setting predominantly derived from plutonic, quartzose sedimentary and metamorphic rocks exposed in the central SSZ. Weathering indices indicate moderate chemical weathering in the source area which may be related to close source-to-sink relationships or arid climate. Our palaeogeographic reconstructions and original geological mapping indicate that the erosion of uplifted basement rocks exposed in horst blocks provided the sediment sources for the syn-extensional deposition of uppermost Jurassic–lowermost Cretaceous conglomerates and Lower Cretaceous siliciclastic red beds within a continental retro-arc basin during initiation of the ‘Neo-Tethys 2?. The polyphase tectonic reactivation along the principal fault of the study area controlled the syn- and post-extensional tectonostratigraphic evolution that reflect the corresponding mechanical decoupling/coupling along the northern Neo-Tethyan plate margin.     

贵金属资源的应用及开发

将贵金属的应用,资源分布,生产和贵金属的分析化学结合在一起进行了综述,由于贵金属资源的短缺性及考虑可持续发展战略,特别介绍了贵金属资源的二次回收问题,并对其将来的发展作了一定的评价和展望。     

Reddening of dune sands—evidence from southeast India

Thin section, SEM, and TEM analyses have indicated that the red ‘teri’ sands of southeast India have formed from weathering in situ of coastal dune sands. The data does not support a detrital origin for the red sands. C¹⁴ dates indicate that dune deposition and weathering, to a maximum depth of 10 m, leading to the formation of a hematite, koalinite and illite rich matrix has taken place rapidly over the past 25,000 years. It is postulated that garnet was a major source of hematite (ferric oxide).     

红层“哑地层”划分对比方法——以东营凹陷南坡始新统为例

针对红层划分对比所面临的难题,在充分吸收前人研究成果的基础上,将现有的多种分层方法相互整合,彼此约束和印证,形成了一套科学、便捷的技术方法,即"接触关系明顶底、岩电特征找界面、多元融合定方案、地震约束建格架"的综合地层划分对比技术。该方法针对红层的特殊性,根据岩电特征对干旱气候的响应变化,充分利用了测、录井资料纵向上的连续性优势(避免了取样分析的局限),以及地震资料横向上的优势,有效地解决了红层纵向划分、横向对比的难题,在济阳坳陷东营凹陷南坡始新统沙河街组、孔店组的应用取得了良好效果。该方法可为其它地区同类复杂地层划分对比提供技术支持。     

岩石物理化学性质对泰宁丹霞洞穴的形成制约

泰宁丹霞红层由铁钙质混合胶结的较松散固结红色砂砾岩构成,岩石胶结物中CaCO3含量较高,抗压强度极低、孔隙度和含水性均较高。当岩石遇水湿润或浸泡时,或者生物风化过程中受到各种动植物分泌的有机酸作用,岩石胶结物中CaCO3易溶解流失,促使丹霞红层进一步软弱松散。冬季水结冰之后体积会膨胀,所以岩层表面产生片状裂隙。通过裂隙的毛细管效应,孔隙-裂隙水由岩石内部向结冰的表面扩散,在表面张力作用下水呈表面积最小的球状。春季化冻时岩石沿球形片状裂隙自由剥落的片状风化,圆球形洞穴开始形成,随着四季交替,年复一年,间歇性结冰和融化过程,使得洞穴逐渐扩大,形成泰宁丹霞各种形态的洞穴奇观。     

浮床无土栽培植物控制池塘富营养化水质

采用浮床无土栽培技术,在池塘水面种植景观植物--陆生植物美人蕉(Cana generalis     

中国南方湿润区“荒漠化”问题讨论

荒漠化是当今世界所面临的严重的环境与社会经济问题,推进荒漠化研究工作对于保护生态环境,促进区域可持续发展具有重要意义。本文在对荒漠化内涵进行系统回顾的基础上,认为除了人为干扰叠加气候性干旱作用导致的荒漠化之外,南方湿润区因水土流失叠加物理性干旱作用导致的极端土地退化也是一种荒漠化,并从物质基础、气候条件、影响因子、形成营力、核心作用和地表过程方面进行比较,最后以南方红层区特殊的"红层荒漠化"为案例,利用实地调查和TM影像的植被覆盖度指标VFC对1992-2013年红层土地退化进行分析。结果显示,在人为反复干扰和其他自然因素作用下地表植被持续退化、群落干旱趋势明显,表土层流失,岩石风化加剧,以致形成类似"荒漠"景观的现象。红层区的退化过程可类比于喀斯特石漠化、红壤山地丘陵退化,但这类极端土地退化现象可否视为"荒漠化",有待于进一步的深入研究。     

Evaluating along‐strike variation using thin‐bedded facies analysis,Upper Cretaceous Ferron Notom Delta,Utah

Thin‐bedded delta‐front and prodelta facies of the Upper Cretaceous Ferron Notom Delta Complex near Hanksville in southern Utah, USA, show significant along‐strike facies variability. Primary initiation processes that form these thin beds include surge‐type turbidity currents, hyperpycnal flows and storm surges. The relative proportion of sedimentary structures generated by each of these depositional processes/events has been calculated from a series of measured sedimentological sections within a single parasequence (PS6–1) which is exposed continuously along depositional strike. For each measured section, sedimentological data including grain size, lithology, bedding thickness, sedimentary structures and ichnological suites have been documented. Parasequence 6–1 shows a strong along‐strike variation with a wave‐dominated environment in the north, passing abruptly into a fluvial‐dominated area, then to an environment with varying degrees of fluvial and wave influence southward, and back to a wave‐dominated environment further to the south‐east. The lateral facies variations integrated with palaeocurrent data indicate that parasequence 6–1 is deposited as a storm‐dominated symmetrical delta with a large river‐dominated bayhead system linked to an updip fluvial feeder valley. This article indicates that it is practical to quantify the relative importance of depositional processes and determine the along‐strike variation within an ancient delta system using thin‐bedded facies analysis. The wide range of vertical stratification and grading sequences present in these event beds also allows construction of conceptual models of deposition from turbidity currents (i.e. surge‐type turbidity currents and hyperpycnal flows) and storm surges, and shows that there are significant interactions and linkages of these often paired processes.