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Paleosalinity records of the Tianluoshan site are derived from measurations data of clay mineral,boron,strontium,barium,after field sampling in three profiles of the Tianluoshan site.The relative sea level changes are discussed according to the lab results.The record indicates that the region where the Tianluoshan site located has witnessed at least three times of relative sea level high-stand before,during and after the Hemudu period.Based on previous researches,this paper also focuses on discussing severa... 相似文献
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选择位于长江三角洲南部区域的3个钻孔CSB4、CSB6和CSB8,开展环境磁学方面的研究,以揭示该地区晚更新世以来沉积物记录的显著气候事件。结果显示：3个钻孔都存在明显的S300低值区域,其变化规律为当S300为低值时,磁化率、ARM和SIRM的值较低,而IRMAF80mT/SIRM和ARM/SIRM的比值相对较高,表明磁性矿物浓度降低、粒度变细。同时S300低值区域沉积物以黄色粉砂质黏土为主,含铁锰质结核。IRM获得曲线定量分析结果揭示：沉积物中赤铁矿等高矫顽力组分的含量相对增加,指示长江三角洲区域3次显著的干旱气候事件。在磁性地层及其AMS 14C、光释光测年基础上,推断3次干旱事件发生的时间分别为163―121 ka B.P.（事件I）、57―42 ka B.P.（事件II）和14―10 ka B.P.（事件III）,对应海平面相对较低时期,季风减弱,降水减少,气候干旱,形成以氧化作用为主的环境。 相似文献
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1959年来珠江三角洲地区的海平面变化与趋势 总被引：5，自引：0，他引：5
验潮站资料的低空间分辨率与卫星数据的短时序是区域海平面变化研究存在的关键难题。本文结合卫星高度计海平面高度距平资料及验潮站数据,基于EOF和最小二乘法重建过去53 年（1959-2011 年）珠江三角洲海平面变化时空序列,并利用主成分分析方法建立区域统一海平面变化时间序列。结果显示,基于EOF和最小二乘法的海平面高度场重建方法能很好地解决卫星高度计资料时间序列不长和验潮站分布稀缺时间不连续等问题,对于海平面变化研究,尤其是关于过去长期的变化过程及特征研究适用性良好。对统一海平面变化时间序列线性拟合显示,近53 年珠江三角洲区域海平面平均变化速率为4.08 mm/yr,且存在近期加速上升趋势。与单站研究相比,该方法较好地表达了区域海平面主要变化特征并剔除可能存在的噪音。径流及厄尔尼诺现象也对珠江三角洲海平面空间变化产生影响。 相似文献
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小波变换在相对海平面变化研究中的应用 总被引：5，自引：5，他引：0
根据广东沿岸14个验潮站的月均序列,应用小波分析方法将其进行时域-频域分解,分析了近40多年来月平均潮位序列的多层次尺度结构,进而研究相对海平面的周期变化和趋势变化。结果表明,用小波变换研究相对海平面在时域-频域中的周期分布及变化时,能较好地揭示周期变化的局部特征;广东沿岸相对海平面变化包含着0.5年、1年、2~4年、10~11年及18~20年左右等周期变化,且周期变化在时间域中具有明显的局部化特征;据实测资料计算,周期变化对海平面的趋势变化影响明显,未消除周期变化的趋势分析结果偏大,用小波变换有效地消除周期变化后得出粤西及珠江口地区沿岸相对海平面变化率,一般而言,广东沿岸海平面呈上升趋势,上升幅度约为0.36~1.2 mm/a。 相似文献
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全新世中期西辽河流域聚落选址与环境解读 总被引：6，自引：0，他引：6
通过x2 检验等方式提出,全新世中期西辽河流域聚落对海拔400~500 m 高程区域选择倾向十分明显,在这一高程内又偏重于距河床10~40 m 的坡地,兴隆洼、赵宝沟以及红山文化期这一特征最突出,夏家店下层文化期聚落位置表现出以400~500 m 高程区为核心向高、低两个方位发展。针对上述聚落环境选择特征指出：① 根据人类生存方式可将西辽河流域划 出林地与草地两大地带,两者的交界处即400~500 m 高程区域内以坡地为主的林缘地带,兴隆洼、赵宝沟文化期人类的采集、渔猎活动主要集中在这里,随着红山、夏家店下层文化期 原始农业的发展,聚落选址从原来的林缘地带向草地甚至林地扩展,前后不同考古文化期的 聚落位置界定了自然环境的空间属性与地域差异。② 西辽河流域受地带性环境因素制约,即使在全新世大暖期林缘地带的动植物资源也并不丰富,仅能满足人口密度极低的兴隆洼、赵宝沟文化期人类获取食物的需求,红山文化以后随着人口增殖原始农业逐渐发展起来。③ 全新世中期西辽河流域聚落密度很低,人口规模在这一地区的环境容量之下,农业开发尚未对西辽河流域带来明显的环境扰动。 相似文献
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采用 P-III 适线拟合法分析赤湾验潮站建站以来的潮位资料,得出该站 1965―2014 年最高潮位的重现期值：其中 100 a 一遇最高潮位为 2.31 m,50 a 一遇最高潮位为 2.18 m。通过插值法分析 1965―2011 年赤湾站与北角/鰂鱼涌站的年最高潮位,得出两者存在显著相关关系,并据此后报出赤湾站近百年来 2 次最高潮位为 1962 年2.7 m 和 1937 年 2.34 m。。根据 IPCC AR5 中的 RCP2.6 方案,预估了 21 世纪末（2081―2100 年）赤湾最高潮位的重现期：100 a 最高潮位在全球海平面上升 0.24 m 的情况下为 2.55 m,在全球海平面上升 0.40 m 的情况下为 2.71m。并讨论了围海造地导致伶仃洋潮位上升率降低以及 0814 号台风“黑格比”对赤湾站增水的影响：赤湾北面西乡沿海地势特别低,当潮位≥1.40 m（珠基起算）时,就会发生海水倒灌现象。也就是说,未来海平面的上升将加大该区海水倒灌频率。通过分析台风过境时该站的潮位观测资料,得出 0814 号台风“黑格比”经过珠江口时赤湾站的最高潮位为增水 1.46 m。最后,重新修订了赤湾站最高潮位的重现期值,这不但能够提高该区域防台水位设计的准确性,还能为该海域的风暴潮预警预报提供参考依据。 相似文献
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全新世以来山东半岛东北部海面变化的河流地貌响应 总被引：6，自引：1，他引：5
对全新世以来山东半岛东北部沿岸的相对海面（基准面）变化,不同河流有截然不同的地貌响应方式。大沽夹河型河流的下游河谷中有分别与相对海面升降对应的溯源堆积期和溯源侵蚀期,但不同规模的河流仍有差异。黄水河型河流河谷未因基准面升降而发生侵蚀或堆积,河谷仅起了输沙通道的作用。此外,大沽夹河型河流的中下游河型在相对海面上升或下降时,还可能发生相应地网状化或曲流化。 相似文献
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JIN Jianhui LING Zhiyong LI Zhizhong ZUO Xinxin FAN Xuechun HUANG Yunming WANG Xiaoyang WEI Changfu REN Yongqing QIU Junjie 《地理学报(英文版)》2022,32(6):1157-1176
The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province. The accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound sites. The sites can also be roughly divided into estuarine, coastal, and sea-island sites based on their geomorphic features. The cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian civilization. Based on luminescence dating of typical Neolithic sites on Haitan Island, their quartz-OSL (optically stimulated luminecesence) burial ages were determined. Synthesizing previously published results, the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed, and the relationship between Neolithic human activities and regional geomorphic processes is analyzed. The results show that: (1) the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic processes. The sites were mainly distributed in the foothills of two high hills along an NNE-SSW trend. With an increase in altitude, the features were distributed as “single site (I) - superimposed site - single site (II)” and appear successively. Single type sites (I) mainly appeared at low sea level, whereas single type sites (II) mainly appeared at high sea level. Superimposed sites were not subject to sea level changes. The relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the region. The single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area, whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns. (2) High sea level caused by the “backwater effect” in low latitude areas in the southern hemisphere, and coastal aeolian sand activity influenced by sea level fluctuations in the middle Holocene correspond well with human activities recorded in the cultural stratigraphy of sea-island type sites. The altitude of coastal aeolian sand accumulation can be used as an indirect index to estimate the age of coastal dunes. 相似文献
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对珠江三角洲中部中山市东升镇附近PRD11孔的岩性和软体动物的分布特征进行分析,并与邻近的PRD10孔以及珠三角其他位置的钻孔记录比较。结果表明：受海平面变化、河流作用和构造升降影响,研究区晚第四纪经历了5个环境阶段：1）约9 010 cal. a B.P.以前,钻孔所在地暴露地表,沉积物遭受风化剥蚀,形成杂色黏土;2）9 010―7 000 cal. a B.P.为全新世大海侵时期,研究区开始发育河口湾环境;3）7 000―5 460 cal. a B.P.,研究区水深短暂下降;4）5 460―3 340 cal. a B.P.水深有所加大,并在约4 546 cal. a B.P.时达到全孔最大水深;5）约3 340 cal. a B.P.以来海水逐渐退出研究区,河流作用增强,研究区逐渐演变为上三角洲平原环境。 相似文献
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Quantifying the sequence stratigraphy and drowning mechanisms of atolls using a new 3-D forward stratigraphic modelling program (CARBONATE 3D) 总被引：1，自引：0，他引：1
This paper describes a new 3‐D forward numerical model (CARBONATE 3D) that simulates the stratigraphic and sedimentological development of carbonate platforms and mixed carbonate–siliciclastic shelves by simulating the following sedimentary processes: (1) Carbonate shallow, open‐marine production, dependent on water depth, restriction and sediment input; (2) Carbonate shallow, restricted‐marine production, dependent on water restriction; (3) Pelagic sediment production and deposition; (4) Coarse and fine siliciclastic input; (5) Erosion, transport and redeposition of sediment, dependent on currents, slope, depth and restriction as well as sediment grain‐size and composition; (6) Dissolution of subaerially exposed carbonate. In this paper the model is used to investigate the controlling mechanisms on the sequence stratigraphy of isolated carbonate platforms and atolls and to predict distinctive architectural signatures from different drowning mechanisms. Investigation of the mechanisms controlling atoll strata shows that although relative sea‐level is the major control, antecedent topography, environmental setting and early diagenesis have profound influence on what stratigraphic geometries and facies develop. Hence care must be taken if sea‐level curves are interpreted from real stratigraphies. Atoll drowning by fast sea‐level rise, by lowered production and by repeated exposure and fast subsequent sea‐level rises are investigated and different stratigraphic signatures for the respective mechanisms predicted. A fast relative sea‐level rise results in a bucket‐shaped morphology developed prior to drowning and a sharp transition from the platform margin facies to a pelagic cover. Drowning caused by lowered platform margin production is predicted to result in the development of a dome‐shaped, shallow‐water shoal over the whole platform top prior to drowning. Fourth order amplitudes of several tens of metres, typical of ‘icehouse’ settings, cause atoll drowning at subsidence rates where atolls subject to fourth order amplitude of only a few metres, typical of ‘greenhouse’ settings, can keep up with the rising sea‐level. In the resultant strata, vertical facies belts are less well developed but horizontally extensive facies bands are more prominent. High fourth order amplitudes (up to 80 m) without sufficient third order scale subsidence will not lead to drowning, however, as the platform can recover in each fourth order lowstand. These results suggest that atolls might be easier to drown in ‘icehouse’ rather than in ‘greenhouse’ conditions but only in situations with suitably high rates of longer‐term relative sea‐level rise or sufficient lag times. 相似文献
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亚洲内陆干旱化是国际古环境研究的热点问题。巴丹吉林沙漠是亚洲内陆第二大流动沙漠,拥有世界最高大的风积地貌——沙山,是亚洲内陆干旱化研究的重要载体。沙山的形成演化与其所在沙漠的环境变迁有关,且真实地记录了区域与全球的气候变化。沙山形成过程研究应从区域地质和环境演化入手。本文从地质演化、环境演化、沙漠沉积、沙漠水文、沙山地貌和沙山形成发育等6个方面阐述了有关巴丹吉林沙漠的高大沙山、沙漠湖泊和沙漠自身的形成演化。认为构造-气候事件是亚洲内陆干旱化的一级控制,地球运行轨道变化是二级控制。自新构造运动始至其趋缓,构造-气候事件始终是巴丹吉林沙漠环境气候的主控因素,地球运行轨道变化也起很大的作用。此时西风环流是中国北方沙漠带环境气候的主要驱动力。新构造运动趋缓后,地球运行轨道变化是中国北方沙漠带环境气候的主控因素,青藏高原对大气环流的影响逐渐显现,东亚季风环流是该地区环境气候的主要驱动力。古水说可以很好地解释沙漠湖泊水的来源问题,沙漠湖泊是通过浅层的地下水路依靠保存在地下的古水来相互补给的。宏观上沙漠湖泊是风蚀湖,高大沙山的维持与沙漠湖泊之间不存在必然的因果关系。风成说可以较好地解释沙山的成因。未来的重要研究方向之一是将沙山、沙漠及其演化一同进行研究,重建沙山和沙漠的演化历史,并探讨它们之间的关系。 相似文献
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通过对海南岛三亚地区铁炉港海湾TLG01钻孔沉积物的AMS 14C和OSL测年,以及对地层岩性特征、亮度、粒度、海生贝壳、有孔虫丰度等进行研究,发现全新世海相层较薄,以砂质潮坪相沉积为主;而下伏晚更新世海相层厚度超过38 m,OSL测年结果显示为MIS-5e及MIS-5d沉积。晚更新世海进―海退系列自下而上依次为砂质潮坪―潮下带―泥质潮坪―砂质潮坪,其中可见较深水的软体动物。MIS-5e细粒的粉砂黏土体积分数先陡增、后缓降,结合粒度及有孔虫丰度、亮度L*等指标,判断MIS-5e初期为最高海平面时期,水深较大,其后海平面逐渐降低;沉积物中陆源粗砂的体积分数不断增加,显示进入了MIS-5d相对低海面时期。MIS-1及MIS-5沉积物粒度三角图,分别与湛江海岛潮间带及不同深度南海表层沉积物同类沉积环境有较好的对照,指示2类不同水深的海相环境。 相似文献
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Coastal morpho-stratigraphy and Holocene relative sea level changes at Tuapaat, southeastern Disko Island, central West Greenland 总被引：1，自引：0，他引：1
The geomorphology of a coarse clastic coastal landscape at Tuapaat (69°24'N 52°36'W), southeastern Disko Island, central West Greenland, is described, and a coastal morpho-stratigraphy of the landscape is constructed. 14 C ages on marine shells, whale bones, peat and gyttja are used to construct relative sea level changes throughout the Holocene. The emergence of SE Disko Island occurred in the early part of the Holocene. The Holocene marine limit is situated ca. 80m a.s.l. Between 4.7 and 1.0ka BP, the relative sea level approached the present sea level and it has probably been below present sea level between 4.7 ka BP and the present. The morpho-stratigraphy in the lowest part of the coastal landscape at Tuapaat suggests a complex late Holocene relative sea level history which includes at least 3-4 transgressions during the last ca. 2.5 ka. 相似文献
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1986―2008年广东沿海海平面变化趋势 总被引：3，自引：0，他引：3
根据1993-2008年TOPEX和Jason-1观测的南海海面高度资料和1986-2008年广东省沿海验潮站潮位资料,分析南海绝对海平面及广东沿海相对海平面变化趋势,结果显示:近16年南海(绝对)海平面平均上升率为4.5 mm/a,近23年广东沿海相对海平面上升率为2～3 mm/a,较南海绝对海平面上升率低1～2 mm/a:月平均海平面及年平均海平面变化均存在极强的同步性,在年平均海平面变化中,验潮站的最高值一致出现于2001年.预估未来30年南海海平面比常年升高9～17 cm.海平面上升将加剧珠江口感潮河段的咸潮灾害. 相似文献
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黄河长江珠江三角洲近30年海平面上升趋势及2030年上升量预测 总被引：44，自引：3，他引：44
黄河、长江和珠江三角洲由于地面沉降等原因,过去30年的相对海平面上升率远大于全球或全国海平面上升率（约1.5mm/a）。下一世纪,根据IPCC的最佳估计,至2030年全球海平面将上升18cm。我国三大三角洲,根据目前地面沉降情况、发展趋势及政府的控制措施,估计2030年相对海平面上升量老黄河三角洲（天津地区）为60cm,现代黄河三角洲（山东省东营市地区）为30—35cm,长江三角洲（上海地区）为30—40cm,珠江三角洲20—25cm,以上估计数可供沿海有关决策部门制订今后长远发展规划及拟订政策时的参考。 相似文献
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选取位于珠江口万顷沙ZK316-2钻孔进行孢粉、硅藻和岩性等分析,重建了珠江口晚更新世以来的海侵海退旋回和古环境特征。孢粉和硅藻分析表明：晚更新世期间该区域主要经历了一次大的海侵海退,期间有2次小的海平面波动。晚更新世地层海相特征明显,孢粉组合指示了温暖湿润的气候环境,其植被以南亚热带常绿林为主,孢粉组合以青冈属、蕈树属、金缕梅科等亚热带种属为主,期间出现的海桑属推测为滨海相沉积,指示了当时海平面的位置。晚更新世的海相沉积尽管14C测年结果为老于30 ka左右,但经过区域孢粉组合、硅藻特征、海平面高度等因素的综合对比分析后认为：下部海相层的年代更可能属于MIS 5期,而期间2次短暂的低海面记录可能与5b和5d海平面波动有关。钻孔上部13.9 m以上为全新世2 232 cal. a B.P.以来的沉积,孢粉分析表明植被仍以亚热带常绿林为主,但人类干扰因素的禾本科、松属、芒箕和火灾记录（炭屑）大量增加,指示了沿海人类活动增强和大规模农业的发展,这与全新世晚期海平面下降和三角洲的快速加积作用基本同步进行。 相似文献
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Settlement distribution and its relationship with environmental changes from the Neolithic to Shang-Zhou dynasties in northern Shandong, China 总被引：3，自引：2，他引：1
In this paper, the spatial and temporal distribution of the settlement sites of six periods from the Neolithic Age to the Shang and Zhou dynasties in northern Shandong was investigated using the ArcGIS program, and the relationship between settlement distribution and environmental changes was discussed, based on the proxy records of climatic and environmental change contained in the sediments from three sections at the Shuangwangcheng site and the previous work. The results show that the climate was warm and humid and the sea level was relatively high during the period of 8000-5000 a BP in the study area, and the ancient people lived in the relatively flat （slope of 〈2°） areas at high elevation （20-300 m above sea level）, such as diluvial tableland and alluvial plain. On the other hand, few archaeological sites in the low-lying plain in the west of the study area indicate that few people lived there during that period. This might be attributed to frequent flooding in the area. After 5000 years ago, the scope of human activity extended to the area close to the sea because the relatively colder and drier climate results in sea-level fall, meanwhile the low-lying plain in the west was occupied by the ancient people. The study area of this period was characterized by the rapid development of prehistoric culture, the intensified social stratification and the emergence of early city-states. However, around 4000 a BP, the abrupt change in climate and the increase in frequency and intensity of floods severely disrupted human activities, and eventually led to the decline of the Yueshi culture. During the Shang and Zhou dynasties, the climatic conditions gradually stabilized in a mild-dry state, which promoted the redevelopment and flourish of the Bronze Culture. The previous situation, which was characteristic of sparse human settlements due to freshwater shortage and unfitted conditions for sedentary agriculture, changed during the Shang and Zhou dynasties in northern coastal wetlands.Local residents effectively adapted themselves to the tough environmental conditions by producing sea-salt, which led to the rapid growth of human activities. 相似文献