辽河三角洲湿地生态循环经济模式探讨

辽河三角洲湿地是我国重要的湿地资源之一。随着经济和社会的快速发展,人们对辽河口湿地土壤、水、生物、矿产等资源的掠夺越来越严重,湿地资源过度开发,湿地退化严重,生态环境失衡。因此,如何保护和利用好辽河口湿地资源并实现良性的生态循环经济,已成为迫切需要解决的问题。根据可持续性评价目标提出了建立生态循环经济模式的5大评价标准:生产性、稳定性、保护性、经济可行性和社会承受力,在此基础上探讨了3种生态循环经济模式。     

Depositional origin of an adverse delta surface slope at Altermarka,northern Norway

Based on grain-size analysis of sediment samples from a delta at Altermarka, it has previously been suggested that two tills were deposited on the delta surface as a glacier planed off the delta topsets and created its adverse surface slope. In this reinvestigation of the delta, there was no evidence that a glacier overrode the surface: the topset beds remain intact and no appreciable till was found. Sediments resembling the ‘till’ samples were located, but soil processes and other sedimentary processes easily account for the wide grain-size distributions of these sediments. As a result, this study cautions against using grain-size analysis, on its own, to interpret the genesis of sediments. Other processes potentially responsible for the adverse surface slope include differential isostatic rebound, recent differential slip along ancient thrust faults, and failure of the delta surface to reach sea level. Based on the sedimentology of the topset beds and the local relative sea level history (indicating the delta (9495±70 ¹⁴C yr BP) formed about the time of the local marine limit (9560–9375 ¹⁴C yr BP) 17 m higher than the delta surface), the feature is determined to have built up below sea level with an adverse surface slope.     

2005 Photometric observations and multiple frequencies of the <Emphasis Type="Italic">δ</Emphasis> Scuti variable V350 Peg

We present the V light curves of δ Scuti type variable V350 Peg, obtained between August and October 2005 at the Ankara University Observatory (AUG) and the TüBíTAK National Observatory (TUG). By application of multiple-frequency analyses using Period04 to 7878 photometric V measurements (which are consist of our 747 V data and 7131 V data obtained at Monegrillo Observatory) of V350 Peg, a five-frequency solution was found to be fitted well to the data. In accordance with the computed Q values for V350 Peg, it was found that this star has probably radial mode with l=0 and g-mode oscillations.     

基于CA和神经网络的长江三角洲区域承载力定量分析

近些年来,越来越多的学者开始关注人类的可持续发展问题,而与之有着密切关系的承载力理论研究可以说是人类研究可持续发展战略的一个分支.本文以长江三角洲地区为研究区,着重介绍了如何用元胞自动机和神经网络相结合的方法对区域承载力进行定量分析,希望对长三角地区的可持续发展提供一些理论依据.     

百色盆地东部凹陷北部陡坡带东段百岗组二段沉积特征分析

通过对研究区内100余口钻井测井资料的综合分析、20余口钻井岩心的详细描述、700多块薄片的详细鉴定,并充分利用地震资料,综合分析了研究区百岗组二段的岩石组合、沉积构造、剖面结构、生物化石、测井相和地震相等特征,认为研究区百岗组二段发育了扇三角洲和湖泊两种沉积相,扇三角洲主要发育在研究区的西北部和东北部,湖泊沉积相主要发育在研究区的南部.     

全新世长江三角洲的发育及其对相邻海岸沉积体系的影响

依据钻孔资料和已发表的文献,对全新世长江三角洲的形成和发育及其对相邻沉积体系的影响作了综合和概括.在末次冰期低海平面时,现今长江三角洲地区可分为下切河谷和两侧的河间地两个古地貌单元.冰后期海平面上升,下切河谷被淹,并转化为河口湾,海水随之扩展到两侧的古河间地.全新世最大海侵时形成以镇江-扬州为顶点的古河口湾.7000～7500年以来,当沉积速率超过海平面上升速度时,长江带来的物质大量沉积,河口湾被充填,并逐渐转变为潮汐平原和三角洲.河口湾被充填之后,长江带来的河流泥沙随之溢出河口湾,进入相邻的河口海岸地区,影响相邻沉积体系的形成和发育.长江泥沙向南进入钱塘江河口湾,在湾顶形成沙坎;向北输运,成为苏北南黄海潮成沙脊的重要物源,影响该潮成体系的形成和发展.舟山群岛海蚀平台上直接覆盖泥质沉积是以退积为主的河口湾向进积的三角洲环境转变的又一证据.长江输沙量在不断减少,而河口滩涂围垦力度在增加,这将导致相邻的河口海岸沉积体系增长速度减缓,出现侵蚀或侵蚀加剧.     

Vertically stacked Gilbert-type deltas of Ventimiglia (NW Italy): The Pliocene record of an overfilled Messinian incised valley

Overfilled incised valleys develop when the rate of sediment supply outpaces the rate of accommodation. An overfilled incised valley presents simple or compound valley-fill architecture, depending on the depth of the valley incision, compared with the height reached by the following sea-level rise.The Ventimiglia incised valley, exposed on the Ligurian coast, north-western Mediterranean margin, presents a spectacular example of compound incised-valley fill, developed in perennial “overfill” conditions. The valley was subaerially incised during the Messinian Salinity Crisis and rapidly flooded by the sea at the beginning of Pliocene, then filled by eleven coarse-grained Gilbert-type deltas during Early–Middle Pliocene time.The basal Messinian unconformity is locally paved with subaerial scree breccias and bioclastic shallow-marine sandstones, and blanketed by bathyal marls. These deposits record the lowstand, transgressive and early-highstand systems tracts of the first valley-fill sequence. The subsequent progradation of Gilbert-type deltas occurred in four stages, or depositional sequences, separated by transgressive marine-marl intervals. Within each depositional sequence, the deltaic bodies display offlapping architecture, recording falling shoreline trajectory, downward shifts in facies, and overall forced regression. The water depth and accommodation in the inundated coastal valley was gradually decreasing with time. The reduced accommodation allowed the youngest deltas to prograde out to the shelf edge, triggering mass collapses and subsequent filling into the newly created slump scars. Some of the deltas probably acted as “canyon-perched deltas” and supplied sediment to the deep-water slope and floor of the Ligurian Basin.The vertical stacking of Gilbert-type deltas is usually attributed, in tectonically active basins, to fault-related subsidence pulses. In Ventimiglia, the accommodation was created by high-frequency eustatic sea-level rises that, probably accompanied by climate controlled reductions in sediment supply, temporarily outpaced uplift, leading to the development of multiple cycles of infill.     

Controls on clastic sequence geometries in a shallow-marine, transtensional basin: the Bohemian Cretaceous Basin, Czech Republic

The Bohemian Cretaceous Basin combines features of a shallow‐water (mostly < 100 m) epicontinental seaway formed during a global transgression with those of a tectonically active, transtensional setting. The basin formed under a greenhouse climate and was affected by strong axial currents. Dense well‐log coverage, combined with locally high‐quality exposures and biostratigraphic control, make it possible to examine in three dimensions the geometries of genetic sequences and interpret their controlling variables. Sand‐dominated deltas formed sequences at several spatial scales that reflect nested transgressive–regressive cycles with durations ranging from tens of thousands of years to millions of years. Progradation directions and distances, thicknesses and internal geometry of the individual sequences were controlled primarily by intrabasinal faulting, basin‐scale changes in subsidence rate, eustatic fluctuations and localized bathymetric changes due to successive filling of the basin. Along‐strike change in sediment input from different parts of the source area and a short‐lived uplift of a secondary clastic source provided additional controls on the sequence geometry. Efficient hypopycnal transport combined with redeposition of fine clastics in shallow water promoted development of steep slopes of sand‐dominated deltas while preventing downlap of muddy clinoforms; most of the suspended load became deposited downcurrent in subhorizontal or gently dipping bottomsets. Long‐term accommodation rates were low during the Early to Middle Turonian, with minor intrabasinal faulting, but became accelerated in the Late Turonian and Early Coniacian. This acceleration was caused at least partly by increased subsidence rate accompanied by structural partitioning of the depocentre and partly compensated by increased sediment input indicating increased uplift rates in the Western Sudetic Island source area. This event probably reflected an increase in the regional strain rate in Central Europe. The succession of two major flooding events in the Early Turonian and late Early Coniacian, separated by a low‐accommodation interval in the Middle Turonian, shows a close similarity to published estimates of long‐term eustatic curves. However, the eustatic component of accommodation rate in the Bohemian Late Turonian and Coniacian is difficult to separate from accelerated subsidence. In several cases, evidence for short‐term (100 kyr scale) forced regressions, independent of basinal structural activity, suggests small‐scale eustatic falls at rates which, as presently understood, cannot be explained other than by a glacio‐eustatic mechanism.     

塔里木盆地巴楚及塔中地区二叠系层序地层学分析

通过钻井、测井以及野外剖面等资料的综合分析,塔里木盆地巴楚及塔中地区二叠系可识别出6个层序边界.除B4为Ⅱ型层序边界外,其他各层序边界均为Ⅰ型层序边界,并以侵蚀下切为特征.根据6个层序边界可将二叠系划分为5个三级层序,这些层序均符合Vail经典层序地层学模式.SQ4层序可识别出湖侵体系域和高位体系域,SQ1、SQ2、SQ3、SQ5层序可识别出低位体系域、海(湖)侵体系域和高位体系域.低位体系域为河流相性质的侵蚀沟谷充填沉积,海(湖)侵体系域为滨浅湖和半深湖沉积,高位体系域为半深湖-滨浅湖以及三角洲沉积,另外,SQ3层序高位体系域上部还发育火山岩.河流相侵蚀沟谷充填沉积和三角洲沉积主要分布在塔东隆起西部斜坡上.     

鄂尔多斯盆地史家湾地区长6油层组层序-岩相古地理

通过岩心描述、岩石薄片鏊定和古生物、物源区和测井曲线等资料的综合分析,对鄂尔多斯盆地史家湾地区上三叠统长6油层组沉积相和层序地层学特征进行了详细研究,确定长6油层组属于河控型三角洲沉积体系.可划分为1个长期、3个中期和10个短期旋回层序.以古盐度的定量计算和盐度分区为依据,进一步确定了史家湾地区长6油层组沉积期的古湖岸线位置.在此基础上,以物源区和沉积相、层序分析成果为基础,选取中期旋回层序的上升和下降相域为等时地层单元编制史家湾地区长6油层组各时期层序-岩相古地理图,结果表明各时期古地理面貌和砂体展布格局主要受湖平面升、降和物源区方向控制.最有利储层发育的水上一水下分流河道主要出现在各中期旋回的湖侵相域,砂体的延伸方向与东北部的主物源方向相平行,此研究成果对史家湾地区长6油藏的后续勘探有重要的指导意义.