湖北江汉盆地潜江凹陷深层地下卤水水文地球化学研究

潜江凹陷是我国东部的一较大型油盐沉积盆地．凹陷内的Ｑ组（渐新统）含盐系地层是一套内陆盐湖相沉积，其中不仅蕴藏着丰富的石油和固体盐类，而且卤水资源也十分丰富．卤水为高矿化度、高ＳＯ含量、低Ｃａ（２＋）、Ｍｇ（２＋）含量的硫酸盐型陆相古盐湖沉积卤水．卤水的ｐＨ值平均为５．６６，总矿化度平均为２８３．２５克／升．水盐体系主要为Ｎａ，Ｋ／／Ｃｌ，ＳＯ４－Ｈ２Ｏ，古卤水水化学类型为Ｎａ２ＳＯ４亚型．卤水中含近２８种化学成分，ＳＯ的平均含量达９６６５．８毫克／升，Ｃａ（２＋）和Ｍｇ（２＋）的平均含量才分别为８９９．４毫克／升和１７３．８毫克／升．Ｋ、Ｂ、Ｌｉ、Ｂｒ、Ｉ等的含量较大，Ｋ、Ｂ、Ｌｉ的含量随Ｃｌ浓度的增加而增加，Ｂｒ、Ｉ的含量随矿化度的增加而增加，随ＳＯ浓度的增加而减少．卤水中绝大多数离子的含量在沉积盆地浓缩中心区大，在理深较大的第四、五、六水层高．     

内蒙古固阳福顺店一带渣尔泰山群褶皱构造研究

通过区调填图对内蒙古固阳一带渣尔泰山群褶皱构造进行了分析研究.在地质演化过程中, 渣尔泰山群主要经历了3期褶皱变形, 即早期的层内褶皱, 主期同斜倒转褶皱与晚期叠加褶皱.早期褶皱形成于中元古代, 系由层间的剪切滑动所至, 主要发育于阿古鲁沟组; 主期褶皱形成于中元古代, 晚期褶皱形成于早古生代; 主期与晚期褶皱均形成于纵弯褶皱机制.由于晚期褶皱对主期褶皱的改造, 形成了较为复杂的叠加构造网络.      

复合荒漠化及其时空变化研究——以新疆艾比湖地区为例

以新疆艾比湖地区为研究区,通过对现有荒漠化监测指标体系的归纳分析,界定了复合荒漠化概念.利用遥感影像数据提取研究区各类荒漠化的现状与动态变化信息.研究结果表明:单一主导因子荒漠化类型面积占荒漠化土地总面积的82.29%,复合荒漠化面积占17.71%.2002～2005年,艾比湖湖面面积缩小了322.507 3 km2,相应的总体土地荒漠化面积增加了7.18%,复合荒漠化面积增加了133%.土地荒漠化的过程同时也发生了变化,风蚀、复合荒漠化增加而土地盐渍化减少,荒漠化程度加重,复合荒漠化类型增加并向其他土地类型扩展.     

东南极中山站附近湖冰与固定冰热力学过程比较

2006年对东南极中山站附近湖冰和固定冰的热力学过程进行了系统观测.基于观测数据比较湖冰和固定冰热力学生消过程;分析湖冰和固定冰温度对气温变化的响应规律;计算不同深度层湖冰和固定冰的垂向热传导通量.结果表明:观测的湖泊和海岸区均在2月底至3月初形成连续冰层;湖冰9月底至10月初达到最大冰厚,早于固定冰1-2个月,湖冰最...     

张性环境中与断裂相关的褶皱类型及特征

张性环境下与断裂相关的褶皱作用 (包括纵向褶皱作用和横向褶皱作用 )的研究刚刚起步 ,以往的研究都将后者归因于走滑扭动或挤压反转的结果。但最新研究表明 ,横向褶皱多与张性环境下正断层作用相关的位移变化密切相关 ,也即横向褶皱是应变控制的构造 ,而不是应力控制的构造。根据相关断裂级别 ,横向褶皱级别也分为 5类 :盆地级别 (一级 )的横向褶皱、控坳及控隆横向褶皱、控凹及控凸横向褶皱、控制断鼻的横向褶皱、小尺度孤立横向褶皱 ,并与断裂分级对应。对张性环境下褶皱同时的干涉和先后的叠加 (统称复合作用 )进行了系统研究 ,对复合褶皱样式进行创新与探讨。这一研究不仅有助于伸展区发现新的圈闭类型 ,指导油气勘探 ;而且在于可创新性地在平面构造图上进行断裂生长顺序和组合规律的定性分析 ,同时还可对沉积相分布、沉积厚度变化等进行对应分析。     

Differences in trophodynamics of commercially important fish between artificial waterways and natural coastal wetlands

Extensive artificial waterways have replaced natural wetlands and created new estuarine habitats on the southern Queensland coast, Australia. Economically important fish species found in adjacent natural wetlands of mangrove, saltmarsh and seagrass also occur in the artificial waterways. Stable isotope analyses (δ¹³C, δ¹⁵N) were used to test whether the relative importance of basal sources of energy varied for foodwebs found in artificial (canals and tidal lakes) and natural waterways. None of the fish species differed in their isotope values between artificial waterways. In contrast, isotopic signatures of snub-nosed garfish (Arrhamphus sclerolepis; Hemiramphidae) varied greatly between natural and artificial waterways, having highly enriched δ¹³C values (−10.5‰) in natural wetlands, demonstrating reliance on seagrass (−11.4‰), and significantly less enriched values (−19.0‰) in artificial waterways, consistent with either local algal sources (−19.8 to −20.4‰) or a mixture of seagrass and other less enriched autotrophs from adjacent natural wetlands. Isotopic signatures of sand whiting (Sillago ciliata; Sillaginidae) were also significantly more enriched in natural (−18.2‰) than artificial (−21.0‰) habitats, but means were not far enough apart to distinguish between different sources of nutrition. δ¹³C values of yellowfin bream (Acanthopagrus australis; Sparidae) did not differ between artificial and natural habitats (about −20‰ in both). δ¹⁵N values of fish varied among habitats only for A. sclerolepis, which in artificial waterways had values enriched by 2‰ over those in natural waterways. This was consistent with a shift from seagrass (relatively depleted δ¹⁵N) as a source in natural habitat to algal sources (relatively enriched δ¹⁵N) in artificial habitats. This study provides some of the first evidence that at least some fish species rely on different autotrophs in artificial waterways than in adjacent natural wetlands.     

Uncertainty Analysis of Wind-Wave Predictions in Lake Michigan

With all the improvement in wave and hydrodynamics numerical models, the question rises in our mind that how the accuracy of the forcing functions and their input can affect the results. In this paper, a commonly used numerical third-generation wave model, SWAN is applied to predict waves in Lake Michigan. Wind data are analyzed to determine wind variation frequency over Lake Michigan. Wave predictions uncertainty due to wind local effects are compared during a period where wind has a fairly constant speed and direction over the northern and southern basins. The study shows that despite model calibration in Lake Michigan area, the model deficiency arises from ignoring wind effects in small scales. Wave prediction also emphasizes that small scale turbulence in meteorological forces can increase prediction errors by 38%. Wave frequency and coherence analysis show that both models can predict the wave variation time scale with the same accuracy. Insufficient number of meteorological stations can result in neglecting local wind effects and discrepancies in current predictions. The uncertainty of wave numerical models due to input uncertainties and model principals should be taken into account for design risk factors.     

准噶尔大型坳陷湖盆坡折带的类型和分布特征

在海相盆地和断陷湖盆中都发育坡折带，并对层序和沉积起重要控制作用，这一观点已得到广泛关注并被普遍接受。对准噶尔盆地侏罗系的研究表明，在大型坳陷湖盆中也发育坡折带，其成因带型丰富，可划分为构造坡折、沉积坡折和侵蚀坡折。并且分布广泛，表现为多级坡折的特点，在剖面上具有正向阶梯状组合、逆向阶梯状组合、沟谷组合、山梁组合和沟梁组合等组合样式；在平面上具有梳状组合、帚状组合、斜交组合、喇叭状组合和平行组合等组合样式。于一定构造背景下发育的一组有成因联系并具类似组合样式特征的坡折带可构成一个构造坡折域。在准噶尔盆地侏罗纪湖盆中共划分出6个构造坡折域。坡折带对层序、沉积和非构造圈闭的发育具有十分重要的控制作用，在不同构造坡折域形成不同的水系和沉积体系特征。     

The benthic macrofauna of the St. Lucia Estuary during the 2005 drought year

The St. Lucia Estuary is the largest estuarine system in Africa. The estuary is part of the Greater St. Lucia Wetland Park, which has been declared a World Heritage Site. This ecosystem has been subjected to severe drought conditions over the last four to five years, resulting in its mouth being closed off from the ocean in June 2002 for a period of over four years. The main aim of this study was to document the effects of the prevailing drought on the macrofauna of the system, since the last work on this benthic component had been undertaken over a decade ago, during a normal-to-wet phase. Macrofauna samples together with physico-chemical data were collected at representative sites in the Narrows, and the South and North lakes in February, April, August and October 2005. The drought exerted a strong influence on the system, leading to hypersaline conditions developing in its northern regions (maximum of 126 at Hell's Gate), and to the loss of aquatic habitat. Ordinations and clustering indicated that the macrofauna of the system could generally be separated into three clusters viz. (1) the Narrows and the southern portion of South Lake, (2) the northern half of South Lake, and (3) the North Lake–False Bay complex. Multivariate correlations indicated weak relationships between macrofaunal community structure and physico-chemical parameters. The distinction in macrofaunal assemblages between these clusters was probably caused by these habitats being physically separated at the peak of the drought, with no water flow between them, thereby preventing exchange of planktonic larvae and retarding colonisation of habitats. There was a northward decline in taxonomic richness and diversity of macrofauna in the system, which correlated positively with water depth and negatively with the biomass of microphytobenthos. It is evident that the drought structured macrofauna communities primarily through its effects on water depth and habitat fragmentation. The results of this investigation provide valuable information regarding the effects of droughts on estuarine–lake systems and the possible mechanisms by which they occur.     

The importance of missing strain in Deep Water Fold and Thrust Belts

Deep water fold and thrust belts (DWFTBs) are sedimentary wedges that accommodate plate-scale deformation on both active and passive continental margins. Internally, these wedges consist of individual structures that strongly influence sediment dispersal, bathymetry and fluid migration. Most DWFTB studies investigate basin- and intra-wedge- scale processes using seismic reflection profiles, yet are inherently limited by seismic resolution. Of critical importance is strain distribution and its accommodation on discrete faults compared to distributed deformation. Recent studies have considered strain distribution by investigating regional reflection DWFTBs profiles within coupled systems, which contain down-dip compression and up-dip extension. There is broad agreement of a mis-balance in compression versus extension, with ∼5% excess in the latter associated with horizontal compaction, yet this remains unproven.Using two exceptionally well exposed outcrops in the Spanish Pyrenees we consider deformation of DWFTB at a scale comparable to, and beyond, seismic resolution for the first time. By coupling outcrop observations (decametre to hectometre scale) with a re-evaluation of seismic profiles from the Orange Basin, South Africa, which contains one of the best imaged DWFTBs globally, we provide a unique insight into the deformation from metre to margin scale. Our observations reveal hitherto unrecognised second order structures that account for the majority of the previously recognised missing strain. This re-evaluation implies that ∼5% missing strain should be accounted for in all DWFTBs, therefore existing studies using restorations of the sediment wedge will have underestimated crustal shortening in active margins, or sedimentary shortening in gravity driven systems by this amount. In contrast to previous studies, our observations imply that the majority of this strain is accommodated on discrete fault surfaces and this can explain the occurrence and location of a range of intra-wedge processes that are intimately linked to structures including sediment dispersal, fluid migration pathways and reservoir compartmentalisation.