Formation and Evolution of Ancient Lakes on South Coast Plain of Laizhou Bay

Based on the data of historical geography, the analysis of the stratigraphic section, and the textual research of place names and satellite photographic interpretations, the authors study the formation and evolution of ancient lakes on the south coast plain of Laizhou Bay where there were once three lakes: Judian Lake, Qingshuibo Lake and Biehua Lake. All the lakes formed 6000 years ago evolved from the lagoons near the estuary and went through two periods, the golden age in the Middle Holocene and the shrinking age in the Late Holocene. The disappearance of the lakes resulted from the drying climate, the migration of the river courses and the activities of human beings. Among the three reasons, the migration of the river courses is the main one.

Element Response to the Ancient Lake Information and Its Evolution History of Argillaceous Source Rocks in the Lucaogou Formation in Sangonghe Area of Southern Margin of Junggar Basin

With the analysis of the element geochemistry characteristics, the ancient lake infor- mation evolution history of the argillaceous source rocks in Lucaogou 0~/~＇~） Formation in San- gonghe area is reconstructed. According to the ancient lake information and total organic matter （TOC） characteristics of argillaceous source rocks, the study section is divided into 6 Subsec- tions. Subsection I mainly developed low-quality source rocks. This is because of the arid climate, high salinity, low lake productivity, unstable preservation conditions in this Subsection. Subsection II mainly developed high-quality source rocks. This is because of the humid climate, low salinity, high lake productivity, stable preservation conditions in this Subsection. Though the paleoclimate was humid and preservation conditions were stable. Lake productivity and the water salinity changed frequently. So Subsection III mainly developed medium-quality source rocks. Because of the humid climate, high lake productivity, medium sedimentary rate and stable preservation conditions, high-quality source rocks were developed in Subsection IV. The preservation conditions were stable, but other ancient lake information changed frequently. Therefore, the quality of the formed source rocks in Subsection V was different. Subsection VI mainly developed high-quality source rocks be- cause of the humid climate, medium sedimentary rate, high lake productivity, low salinity and good preservation conditions. In summary, the ancient lake information parameters and TOC characteris- tics of each Subsection are different from each other.

Evolution of an Ancient Large Lake in the Southeast of the Northern Tibetan Plateau

Nam Co is the largest (1920 km2 in area) and highest (4718 m above sea level) lake in Tibet. According to the discovery of lake terraces and highstand lacustrine deposits at several places in Nam Co and its adjacent areas, the authors confirm the existence of an ancient large lake in the southeastern part of the northern Tibetan Plateau. On the basis of the U-series, 14C and ESR dating, coupled with the levelling survey of lake deposits and geomorphology, the evolutionary process of the ancient large lake in the southeastern part of the northern Tibetan Plateau may fall into three stages: (1) the ancient large lake stage at 115-40 ka BP, when the ancient lake level was 140-26 m above the level of present Nam Co; (2) the outflow lake stage at 40-30 ka BP, when the ancient level was 26-19 m above the present lake level; and (3) the Nam Co stage since 30 ka BP, when the ancient lake level was < 19 m above the present lake level. During the ancient large lake stage, a large number of modern large, medium-sized and small lakes, including Nam Co, Siling Co and Zhari Namco, in the southeastern part of the northern Tibetan Plateau, were connected into a single large ancient lake, rather than several separate lakes connected by river channels. Its areal extent may have gone beyond the watersheds of the modern endorheic and exorheic drainage systems; so it may be called the 'ancient east lake', 'ancient south lake' and 'ancient west lake'. It might also be connected with other ancient lakes in the southern and western parts of the northern Tibetan Plateau to form a unified 'ancient large lake' on the northern Tibetan Plateau.

Simulation of the dynamic disturbance characteristics of the soft sediment in the Diexi ancient dammed lake,China

In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China,10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments.In this paper,the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations.A two-to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions.The results support the following conclusions:(1)The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region.(2)The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation.(3)The greater the earthquake intensity is,the greater the disturbance amplitude is;moreover,the lower the consolidation degree is,the greater the disturbance amplitude.(4)The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region.These results are valuable for ongoing palaeoseismic research in the region.

Possible relatedness between the outburst of the Diexi ancient dammed lake and ancient Chengdu’s cultural change

The Diexi ancient dammed lake is in the upper reaches of the Minjiang River.Six terraces with lacustrine sediments occur at the base.These terraces are the products of the graded outburst of the Diexi ancient dammed lake.The outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the Minjiang River.In this paper,on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain,and the environmental indicators of each sediment layer were tested.Through a comparative analysis of the environmental indicators in the sediments at the two locations,the following results were obtained:the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent changes.The most important finding is that the types and content of the major pollen taxa at the two locations are similar.The Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the Minjiang River.Considering that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake,this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake.

Ancient European Lakes: Reservoirs of Hidden Microbial Diversity? The Case of Lake Pamvotis (NW Greece)

Ancient European lakes are clustered within a radius of 300 km around Lake Ohrid. Information concerning microbial diversity in these lakes is limited. We studied diversity of the dominant prokaryotic phylotypes in the sediments in one of these lakes, known as Lake Pamvotis. The analysis was performed in samples from two stations for four seasons of the same year. DNA extraction followed by PCR amplification (16S rDNA), Denaturing Gradient Gel Electrophoresis, cloning and sequencing was applied in order to reveal the sequence signatures of the dominant bacterial and archaeal phylotypes. Bacterial and archaeal cell numbers were quantified by real-time PCR. Several environmental variables measured in parallel, including pH, Nickel, Chromium, Arsenic, Calcium, Total Nitrogen and Total Carbon, were found to affect strongly the prokaryotic abundances. Most of the identified sequences of Bacteria belong to Proteobacteria and most of the sequences of Archaea belong to Euryarchaeota. The great majority of these bacterial (84.21%) and archaeal sequences (95.65%) have no cultivated counterparts in the databases. In addition, many of these bacterial (50.88%) and archaeal sequences (20.65%) correspond to potentially new species. Six of the bacterial sequences constitute a new class of Cyanobacteria which we have named “Lake Pamvotis cluster” (LPC). Our findings highlight Lake Pamvotis as a habitat for several previously unidentified species of Bacteria and Archaea.

The Evolution of the Quaternary Salt Lakes in the Qaidam Basin

The paper discusses the distribution of Quaternary sediments, occurrence of saline minerals and phases of neotectonic movements and their manifestations in the Qaidam basin. The formation of four successive lacustrine terraces in Tertiary anticlinal zones in the western part of the basin was related to the neotectonic movements that took place 100 Ka ago, and the distribution of such terraces discloses, in a way. the evolutionary history of the Quaternary salt lakes. According to the distribution of the terraces coupled with the distribution of Quaternary sediments and features of salt deposition, four periods of Quaternary salt lake evolution in the basin may be distinguished, which correspond to four stages of salt deposition respectively.

An integrated north–south paleo-Dadu-Anning River: New insights from bulk major and trace element analyses of the Xigeda Formation

The Xianshuihe-Anninghe fault extends SE–S and constitutes the southeastern margin of the Tibetan Plateau.However,the Dadu River which is associated with the fault does not flow following the path,but makes a 90ºturn within a distance of 1 km at Shimian,heading east,and joins the Yangtze River,finally flowing into the East China Sea.Adjacent to the abrupt turn,a low and wide pass near the Daqiao reservoir at Mianning separates the N–S course of the Dadu River from the headwater of the Anning River which then flows south into the Yunnan Province along the Anninghe fault.Therefore,many previous studies assumed southward flow of the paleo-Dadu River from the Shimian to the Anning River.However,evidences for the capture of the integrated N–S paleo-Dadu-Anning River,its timing,and causes are still insufficient.This study explored the paleo-drainage pattern of the Dadu and Anning Rivers based on bulk mineral and geochemical analyses of the large quantities of fluvial/lacustrine sediments along the trunk of the Dadu and Anning Rivers.Similar with sands in the modern Dadu River,the Xigeda sediments also exhibit a granitoid affinity with the bulk major mineral compositions of quartz(>50%),anorthite(about 10%),orthoclase(about 5%),muscovite(about 5%),and clinochlore(about 4%).Correspondingly,bulk major elements show high SiO_(2),with all samples>60%,and some of them>70%,low TiO_(2)(≤0.75%),P_(2)O_(5)(≤0.55%),FeO*(≤5%),and relatively high CaO(1.02%–8.51%),Na_(2)O(1.60%–2.52%),and K_(2)O(2.17%–2.71%),with a uniform REE patterns.Therefore,synthesizing all these results indicate that these lacustrine sediments have similar material sources,which are mainly derived from its course in the Songpan-Ganzi flysch block,implying that the paleo-Dadu originally flowed southward into the Anning River and provided materials to the Xigeda ancient lake.The rearrangement of the paleo-Dadu River appears to be closely related to the locally focused uplift driven by strong activities of the XianshuiheXiaojiang fault system.

关于黄河与河套古湖河湖关系演变的假说性分析——兼论对黄河内蒙古段生态治理的启示

黄河曾经在流经河套盆地过程中形成吉兰泰、乌兰布和、巴彦淖尔、呼包4个古湖,且在高湖面时期连成统一的“河套古大湖”,其后4湖分离并分别演绎了自己的河湖关系。在研习前人相关成果基础上,通过建立整体假说性解释框架,试图按照历史顺序与逻辑顺序统一的要求对该河段河湖关系的演变过程进行重建,并为与之相关的生态系统的治理提供借鉴。研究认为:主河道构建是黄河主动实施填湖、建堤、造槽并“甩湖”的过程与结果;冲积扇是黄河填湖的主要模式,而冲积扇顶附近凸起则是湖口淤塞、移动并最终筑成黄河自然堤的主要原因;巴彦木仁与磴口两地控制点对形成鄂尔多斯一侧黄河主河道起到了关键性作用;黄河西派在高湖面期间从巴彦木仁湖口注入吉兰泰-乌兰布和古湖,与从北面入湖的黄河水共同促成贺日木西尼古砂嘴及其延伸砂脊生长,并在低湖面期将这两个湖分离。基于对所述黄河历史过往的认识,须尽可能立足高效集成利用有限水资源这一观念,将减灾与适度重造沿河湖泊和绿洲结合,营建可持续的内蒙古段黄河生态体系。

大渡河上游阿娘寨古堰塞湖的发现及其特征

古堰塞湖的沉积特征研究是开展堰塞湖古环境、古气候研究的基础。大渡河上游小金川两岸多地出露粉砂质黏土、砂和砾石构成的堰塞湖剖面,通过沉积学分析、光释光测年以及对堵江坝体的岩性构造分析,认为小金川在距今(15.7±1.9)~(9.1±1.0)ka期间发生了一次重大的堵江—堰塞—溃决事件,且该古堰塞湖的沉积环境随时间和空间的变化发生迁移:时间上,堰塞湖经历了形成、充填和溃决3个阶段;空间上,从下游至上游划分出深—半深湖、浅湖、滨湖和河湖交汇区4个沉积区,该古堰塞湖是由阿娘寨古滑坡堵江形成,据此命名为阿娘寨古堰塞湖。该古滑坡主要受控于岩性和构造作用。本次研究进一步丰富了青藏高原东南缘山区大型古堰塞湖的研究成果,其沉积特征、年代和成因特征为后续的深入研究提供了基础材料。

淮安市古运河幸福河湖创建思考

为了探索分析幸福河湖建设经验,本文在分析淮安市古运河基本情况和特点的基础上,总结了古运河幸福河湖打造创建创新举措:管护模式创新、生态运河和文化运河创建、运河水利遗产保护与传承等。同时总结出幸福河湖建设启示:安澜之河是基本保障,以及强化水环境治理、维护河湖健康水生态、推进先进水文化建设、强化幸福河湖建设宣传引导等,以期为建设更多造福人民的幸福河湖提供借鉴。

古代惠州西湖风景教化载体的类型特征

古代惠州西湖风景是当地民众人居环境的重要组成部分,教化民众是其基本功能之一。通过综合风景与教化已有研究成果,指出古代风景教化研究中风景园林史与社会史交叉研究的内在理论关联和风景作为教化载体的类型特征是实现风景教化基本的研究问题。借鉴社会史研究的学术视野和理论方法,将惠州西湖风景教化载体划分为“自然开发对象”“社会仪式场所”和“艺术传播媒介”三种基本类型,并以当地民众为主体视角,提炼和阐释西湖风景教化载体生存主导、政教融合以及形式综合的基本特征。有助于揭示古代风景与民众生存生活的关系,理解风景教化功能的基础,为现代风景名胜的文化传播和培育发展提供一定的历史经验。

多源遥感融合技术在古湖岸识别中的应用——以察尔汗盐湖为例

多源遥感融合技术在识别被侵蚀或被覆盖的古湖岸线方面具有独特的优势。察尔汗盐湖为我国最大的第四纪液体钾盐矿床,识别该盐湖晚更新世以来的多级古湖岸及其湖面变化过程,对于保障我国的钾肥安全具有重要的意义。本研究以合成孔径雷达(SAR)哨兵一号数据(Sentinel-1A)为数据源,应用IHS融合、PC融合、GS融合和HSV融合4种融合方法对高分辨率多光谱哨兵二号数据(Sentinel-2B)在察尔汗盐湖区域进行了融合实验,并对融合结果进行精度评价;选取信息熵、互信息、平均梯度、空间频率、标准差、相关系数、差异相关性总和以及视觉保真度8种客观评价指标对融合结果进行了计算与分析。利用野外实测古湖岸的遗迹高程结合数字高程数据(DEM)对岸线进行模拟,并生成地形剖面图,来恢复晚更新世以来察尔汗盐湖古湖岸动态变化。结果表明,融合方法中的HSV算法是最适合应用于察尔汗盐湖古湖岸线的提取,对恢复晚更新世以来被侵蚀和覆盖的三级古湖岸线地貌具有较好的效果。

太湖古村落空间活化的策略探究——以翁巷古村为例

传统村落在现代文明和大规模城市建设的冲击下面临着严重的生存和发展问题,亟须采取有效措施促进它们的活化和振兴。文章以翁巷古村为例,探讨太湖古村落空间的活化策略。首先,通过对该村落的历史、现状和问题进行分析,发现存在传统人文环境流失、特色产业参与不足、公共空间不足和旅游环境不友好等问题。根据翁巷古村的实际情况,提出了具体的实施方案,包括引入传统建筑功能、增加文化历史展示、鼓励村民个体参与、明确景区节点标识和改善公共空间与设施等方面。

古丹阳湖区传统圩田聚落文化景观构成与变迁初探——以高淳杨家村为例

文章以高淳杨家村为例,梳理因产业结构、交通方式变革导致的聚落变迁历程,描述了当代杨家村文化景观的物质与非物质要素构成,提出了以日常性、历史意识与层级性为主要特征的要素互动形式,并将其诠释为当地人对文化身份、集体记忆和社会结构的隐性表达,希望为古丹阳湖地区传统圩田聚落文化遗产的保护提供一定的参考。

陶唐古国与运城盐池

陶唐古国的兴起与运城盐池密切相关。唐人具有尚武精神,逐步发展起来,出现了君主和武士阶层,建立了官僚机构和军队,占领了河东地区,控制了运城盐池,长期从事池盐生产和运销,发展为强大的部落国家。运城盐池的池盐生产和运销不仅基本满足了黄河中下游地区居民的食盐需求,而且给陶唐古国提供了稳定可靠的财政收入,为陶唐古国的发展奠定了经济基础。在唐部落发展过程中,运城盐池的池盐生产和运销起了至关重要的作用。

禁渔后时代鄱阳湖传统渔业生产习俗传承保护和发展建构研究——以鄱阳县古渔村管驿前为例

传统渔业生产习俗是古代渔业先民生产劳动和生活智慧的结晶,具有较高的历史价值、文化价值和社会价值。禁渔后时代,鄱阳县古渔村管驿前传统渔业生产习俗传承保护和发展建构,应当坚持以新发展理念为引领、以新型集体经济为基础、以渔俗特色谋发展,通过打造管驿前传统渔业生产习俗的集体记忆文化空间、文化产业、历史文化名村、全域旅游、节庆活动和数字化传播平台,实现传统渔业生产习俗传承保护和乡村发展的互融共存、互促互进、同频共振,形成时空文化连续体和习俗文化发展共同体,不断助推乡村社会发展和百姓共同富裕。

淮阳古城形态特征识别与生成原则探析

中国在农业社会时期的城市形态类型多样且极具特色,展示出地域差异和历史发展差异,蕴藏着先民适应自然和改造自然的智慧。文章以黄泛平原“水上古城”——淮阳古城为例,从动态的视角去认识城市形态,借助遥感影像图与历史地图数据,以转译、分析不同时期城市形态在演变过程中展现出的特征,探索此类特征出现所蕴藏的原因和演变逻辑,为未来淮阳的城市规划建设提供科学策略。

辽东湾地区烃源岩特征及其主控因素

根据烃源岩地球化学、岩石学、沉积学、构造沉降及古气候等特征,对辽东湾地区古近系3套湖相烃源岩发育的主控因素进行综合分析。结果表明:3套烃源岩均形成于温暖湿润的还原环境,生产力高;沙三段烃源岩形成于快速沉降的深水窄盆环境,水体根据温度和弱盐度分层,且具最高生产力;沙一段烃源岩形成于沉降速率低的浅水广盆环境,水体根据高盐度分层,且有机质生源高等植物贡献小;东下段烃源岩形成于快速沉降的深水广盆环境,水体根据温度和弱盐度分层;同层内烃源岩的差异受沉积相控制;沙三段烃源岩生烃潜力最好,沙一段次之,再次为东下段。

莱州湾南岸平原古湖泊的形成与演变

运用查阅历史文献、地层剖面分析、地名考证、卫片解译等多种方法确证了莱州湾南岸古湖泊的存在 ,同时研究了它的形成与演变过程。莱州湾南岸有巨淀湖、黑冢泊、别画湖等古湖泊 ,它们形成于距今约 6 0 0 0年以前 ,系由河口湾泻湖演变而成。该区古湖泊经历了中全新世全盛期和晚全新世收缩期两个阶段。湖泊消亡的原因是气候变干、河道迁移、人类活动影响等 ,其中河道迁移是最主要原因。