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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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海平面上升对珠江三角洲经济建设的可能影响及对策 总被引：20，自引：2，他引：20
珠江三角洲地势低平,易受海平面上升影响。预测50年后本区海平面将至少上升0.5-0.6m。本文分析了海平面上升对本区经济建设的直接影响和间接影响,并提出基本对策。 相似文献
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珠江三角洲脆弱性研究进展 总被引：3，自引：0，他引：3
珠江三角洲是我国第二大河三角洲。随着全球变暖、海平面上升和人类活动的加强,珠江三角洲自然的固有脆弱性和人为的特殊脆弱性显著增强。自然的固有脆弱性包括基底沉降、新构造运动、地震、软土层、海平面变化、海水入侵、风暴潮与洪水等;人为的特殊脆弱性包括污染、过度采砂和抽水、人工填土及人工建筑等。通过对目前珠江三角洲各项脆弱性分散研究文献和资料的收集汇总,把珠江三角洲作为一个整体系统进行归纳分析研究。结果表明这些脆弱性的研究还存在初级定性描述、相互矛盾、缺乏整体性和系统性,监测-预警-应急机制不够完善。认为珠江三角洲脆弱性研究还应加强定量分析,采用新的方法和手段,重视各脆弱性之间的耦合作用及珠江三角洲脆弱性变化对人类社会经济发展的影响,重点研究珠江三角洲对脆弱性变化的自适应性。 相似文献
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1970―2009年粤东(汕尾)沿海海平面变化研究 总被引：1，自引：0，他引：1
通过对汕尾站、遮浪站潮位距平资料(SLA)与卫星观测的附近海平面高度距平资料(SHA)以及全南海海平面高度距平资料(SSHA)的比对,探讨资料的代表性和长期变化。结果表明,绝对海平面与相对海平面的多年变化趋势基本一致。采用随机动态法和二次项拟合方法分析得出,汕尾多年海平面变化呈波动上升趋势,存在显著的1年、半年、4个月和19年周期,其中年振幅为10.6 cm,且海平面高低受厄尔尼诺事件影响明显。海平面的季节变化特征与季风呈现显著相关性,认为季风导致的海面增减水对海平面的高低存在一定的作用,预估2050年海平面较常年平均高31±3cm。 相似文献
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近百年广东沿海海平面变化趋势 总被引：5，自引：3，他引：2
为预估本世纪末广东海平面的可能上升量,从探讨近百年来广东海平面上升率的阶段性变化入手,通过对广东沿海验潮站潮位观测资料的统计分析,得出广东沿海海平面近86年(1925-2010年)、近40年(1970-2010年)和近20年(1993-2010年)的上升率分别为2.1 mm/a、2.5 mm/a和3.2 mm/a,存在加速上升的趋势,并与全球大体呈准同步变化.20世纪90年代以来,广东沿海海平面上升和热带西太平洋的海平面出现突变上升有密切关系. 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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黄河三角洲利津超级叶瓣时空范围的再认识 总被引：1，自引：0，他引：1
黄河三角洲是世界著名的河流三角洲之一。自有学者首次系统地提出黄河三角洲全新世10期超级叶瓣的时空分布范围后,这一观点近30年来未见明显的改进。借助渤海湾南岸研究区获得的4个20～30 m钻孔地层资料和相应的AMS14C测年数据,以及前人部分钻孔的研究成果,本文对黄河三角洲利津超级叶瓣的沉积演化框架和时空分布特征进行了重新厘定:研究区全新世沉积环境由早期的河道和泛滥平原沉积,逐渐向海侵过程中盐沼、潮坪和浅海相演化。海平面上升速率减缓之后三角洲开始发育并逐步成陆,直至最后被陆相沉积所覆盖。黄河下游古河道在9000-8000 cal a BP左右可能在黄骅南部入海;大约8000 cal a BP之后,黄河主河道南迁到滨州—惠民一带,并在7000-5500 cal a BP之间发育利津超级叶瓣;利津超级叶瓣的北界可能在马山子和阳信一界,而南界在郭井子和弥河之间;约5500 cal a BP之后,黄河下游古河道可能重新过黄骅入海,于5500-3500 cal a BP左右形成黄骅超级叶瓣;约3500 cal a BP之后,黄河古河道北迁至天津,直至～700 BC左右主流河道入海口再次南迁至河北岐口附近。 相似文献
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《广东海平面变化及其影响与对策》研究,全省１３个有关单位共７８位科技人员参加,历时４年,对广东海平面进行了比较系统而深入的研究,取得了下列的新进展。１４０年来广东相对海平面上升速率为２～２５ｍｍ／ａ关于广东数十年来相对海平面上升速率,前人至少有３２... 相似文献
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烟台附近海岸风沙地貌的初步研究 总被引：5，自引：0，他引：5
在野外调查基础上,对烟台附近海岸风沙分布、风沙地貌类型及地貌发育过程进行了探讨。指出全新世海岸变迁是海岸风沙地貌发育的基础,6000aB.P.以来有5个风沙堆积期,前4个风沙堆积期与4个海平面下降期一致,第5风沙堆积期与小冰期一致。 相似文献
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The Holocene evolution of the shallow alluvial valley occupied by the Red River was investigated at two successive river meanders near St. Jean Baptiste, Manitoba. A transect of five boreholes was sited across the flood plain at each meander to follow the path of lateral channel migration. From the cores, 24 wood and charcoal samples were AMS radiocarbon dated. The dates from the lower half of the alluvium in each core are interpreted to represent the age of the lateral accretion deposits within the flood plain at the borehole sites. The ages of these deposits increase progressively from 900 to 7900 and 1000 to 8100 cal years B.P. along each transect, respectively, from the proximal to distal portions of the flood plain. At the upstream meander, the average rate of channel migration was initially 0.35 m/year between 7900 and 7400 cal years B.P., then decreased to 0.18 m/year between 7400 and 6200 cal years B.P., and subsequently varied between 0.04 and 0.08 m/year. Net channel incision of the river since 8100 cal years B.P. is estimated to have ranged between 0.4 and 0.8 m/ky. The pre-6000-years-B.P. interval of greater channel migration is hypothesized to reflect a higher phase of sediment supply that was associated with the establishment of the river system on the former bed of glacial Lake Agassiz. Since 1000 years B.P., the outward migration of the meanders has caused a gradual enlarging of 0.7–2% in the cross-sectional area of the shallow valley at the two meanders. When considered proportionally over timescales of up to several centuries, the widening of the valley cross-section is very low to negligible and is deemed an insignificant factor affecting the modern flood hazard on the clay plain. 相似文献
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为了揭示闽江下游闽侯盆地第四纪沉积环境演变与人类活动历史,对闽江下游闽侯盆地庄边山遗址附近的FZ5钻孔进行了孢粉、硅藻分析。结果表明：闽侯盆地全新世海侵初始发生时间约为9 000 cal. a B.P.,至7 500 cal. a B.P.达到最大海侵范围,晚全新世海退的发生时间在闽侯盆地大约为1 900 cal. a B.P.。孢粉分析证实了当地早中全新世温暖的亚热带气候以及浓密的常绿阔叶林植被。在7 500―1 900 cal. a B.P.之间无论植被覆盖还是气候环境均比较稳定,高海平面时期的适宜气候以及海湾环境也有利于当地以渔猎经济方式为主的新石器文化（昙石山文化）的兴起和发展。自1 900 cal. a B.P.以后,孢粉组合突变为以先锋植物芒萁属（Dicranopteris）、禾本科（Poaceae）、松属（Pinus）等类型为主,揭示了当地植被受到人类农业刀耕火种的影响而发生显著变化。高含量的禾本科花粉（含一定数量的水稻）仅在剖面上部明显增加这一事实,证实了闽侯和福州一带水稻种植的大面积发展始于距今1 900 a前后。 相似文献
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通过对澧阳平原优周岗遗址剖面沉积样品孢粉分析,重建了该区5500 a B.P.~4000 a B.P.气候、水文、植被变化和人类活动历史。结果表明：距今5500~5200年大溪文化晚期,气候环境较为适宜;距今5200~4000年的屈家岭—石家河文化时期,气候暖湿程度先升高后降低,转折点在4800 a B.P.左右。其中,距今4200~4000年的石家河文化晚期,气候向干凉化发展。孢粉组合显示优周岗遗址周边一直有湿润生境存在,且在屈家岭文化中晚期和石家河晚期出现湿生草本、蕨类孢子和藻类的明显增加,反映两次水文变化过程。优周岗遗址大溪文化时期常绿和落叶阔叶林已遭破坏,稻作农业有一定发展,屈家岭—石家河文化早中期稻作规模扩展。然而石家河文化晚期,稻作农业规模明显收缩,可能与区域文化衰落有一定关系。 相似文献
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六千年来韩江三角洲的滨线演进与发育模式 总被引：1，自引：0，他引：1
本文应用14C年代学、沉积学、地貌学、历史地理学,现代动力过程等方法,论证了距今6000年、5000年、4000—2500年,汉代、唐初、宋末、清末的滨线位置及其演进趋势。提出其6000年来的发育模式为:1.三角洲两期发育,河流两级分汊;2.沙洲(沙堤)併岸,平原扩展;3.洪泛(风力)加积,地面堆高;4.右汊萎缩,左汊发展,干流左移。 相似文献
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Kettle ponds in the Cape Cod National Seashore in southeastern Massachusetts differ in their evolution due to depth of the original ice block, the clay content of outwash in their drainage basins, and their siting in relation to geomorphic changes caused by sea-level rise, barrier beach formation, and saltmarsh development. Stratigraphic records of microfossil, carbon isotope, and sediment changes also document late-glacial and Holocene climatic changes.The ponds are separated into 3 groups, each of which follow different development scenarios. Group I ponds date from the late-glacial. They formed in clay-rich outwash, have perched aquifers and continuous lake sediment deposition. The earliest pollen and macrofossil assemblages in Group I pond sediments suggest tundra and spruce-willow parklands before 12 000 yr B.P., boreal forest between 12 000 and 10 500 yr B.P., bog/heath initiation and expansion during the Younger Dryas between 11 000 and 10 000 yr B.P., northern conifer forest between 10 500 and 9500 yr B.P., and establishment of the Cape oak and pitch pine barrens vegetation after 9500 yr B.P. Sedimentation rate changes suggest lowered freshwater levels between 9000 and 5000 yr B.P. caused by decreased precipitation on the Atlantic Coastal Plain. Lake sediment deposition began in the middle Holocene in Group II ponds which formed in clay-poor outwash. These ponds date from about 6000-5000 yr B.P. In these ponds sediment deposition began as sea level rose and the freshwater lens intersected the dry basins. The basal radiocarbon dates of these ponds and stable carbon isotope analyses of the pond sediments suggest a sea-level curve for Cape Cod Bay. Holocene topographic changes in upland and the landscape surrounding the ponds is reconstructed for this coastal area.Group III ponds in the late Holocene landscape of the Provincelands dunes originated as interdunal bogs about 1000 yr B.P. and became ponds more recently as water-levels increased. Peat formation in the Provincelands reflects climatic changes evident on both sides of the Atlantic region.This is the 8th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest editor for these papers. 相似文献
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The Late Weichselian and Holocene shoreline displacement on the west-central coast of Svalbard 总被引：1，自引：0，他引：1
Three well-developed raised marine shorelines along Nordenskioldkysten have been studied and correlated with the shoreline displacement since the last deglaciation. The marine limit of 64 m in the area is of Late Weichselian age and has been dated to 10, 900- 11, 000 years B.P. An intermediate level at 50 m is estimated to be 10, 600-10, 000 years old and demonstrates a sea level stagnation probably caused by a glacier readvance in eastern Svalbard during the Younger Dryas. A Holocene transgression culminating shortly after 6, 000 years B.P. has been stratigraphically demonstrated, and it probably correlates with the Tapes transgression of Scandinavia. No pre-Late Weichselian marine levels are found, and the large rebound can be attributed only to a Late Weichselian glaciation. 相似文献
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Mapping in the Galweda-Elayu area of northern Somalia has revealed depositional and erosional marine terraces at elevations of approximately 16 m, 8 m, and 2 m. These terraces vary from 0–2300 m, 200–2200 m, and 0–800 m in width, respectively. Sediments exposed in stream-valley walls demonstrate that the two higher terraces were formed by marine transgressions followed later by regressions to below present sea level. Beach ridges on the terraced alluvial fan at the mouth of togga Galweda imply that sea level and/or land elevation varied by at least 6 m during the formation of the 16-m terrace and by at least 3 m during the formation of the 8-m terrace. 230Th/234U ages of corals suggest that the 8-m terrace was formed during deep-sea isotope substage 5c (105 kyr B.P.) and the 2-m terrace during substage 5a (80 kyr B.P.). A 7-kyr-old coral from above the present storm beach on the outer flanks of the 2-m terrace suggests that sea level in the Gulf of Aden was close to its present level by the middle Holocene. No material suitable for dating was recovered from the 16-m terrace, but on morphological grounds and based on marine-terrace elevations elsewhere in the Red Sea-Gulf of Aden rift zone, we believe that the 16-m terrace was formed during isotope substage 5e (132–120 kyr B.P.), when global sea level was about 6 m above present. 相似文献
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A paleoenvironmental model is proposed for the western shoreline of Cape Cod Bay, Massachusetts, from about 9,000 through 5,500 years B.P. Central to this reconstruction is the integration and correlation of the glacial sediments, radiometric chronology and pollen stratigraphy of an exposed peat deposit located near Nameloc Heights, Plymouth, Massachusetts. Four Carbon-14 dates provide a chronology and suggest an average rate of peat accumulation of about 6 cm/100 years from 8,800 through 7,400 years B.P., decreasing to 3 cm/100 years from 7,400 to 5,500 years B.P. This sequence of radiometric dates provides a temporal framework within which the pollen taxa of the peat deposit can be correlated to the established floristic zones of the southern New England region. 相似文献
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John O. Solem Thyra Solem Kaare Aagaard Oddvar Hanssen 《Journal of Paleolimnology》1997,18(3):269-281
Invertebrate colonization of lakes following the uplift of land from the sea was studied in four lakes, currently situated between 39 and 24 m a.s.l., on the central Norwegian coast. The lakes were isolated from the sea between 9500 and 7700 years B.P. Animal and algal remains picked from core samples showed that the first colonizers preserved as fossils were usually members of the Chironomidae, Daphnidae/Chydoridae, Acarina, Porifera (Ephydatia mülleri and Spongilla lacustris), Bryozoa (Cristatella mucedo and Plumatella spp.) and Charophyta (Chara sp.). Of the chironomids, the genus Chironomus was present in the oldest lacustrine layers of all four lakes, but other genera recorded at the marine/lacustrine boundary were Dicrotendipes, Procladius (?), Einfeldia, Microtendipes, and Glyptotendipes. Remains of the caddis fly family Limnephilidae were also present in the earliest lacustrine sediments in Kvennavatnet and Kvernavatnet. The oldest invertebrate fauna is typical for mesotrophic lakes. However, chironomids and mites have been present in this area from at least about 10?500 years B.P. A diverse chironomid community was established between 300 and 800 years after isolation from the sea at Kvernavatnet on the island of Hitra, while only between 80 and 120 years passed before a comparably diverse community developed at Kvennavatnet on the mainland coast. A similar development of the invertebrate fauna occurred in Kvennavatnet, Kvernavatnet and Storkuvatnet. However, Litjvatnet deviates greatly from the ‘normal’ pattern because a tsunami disturbed the bottom sediments and fauna. The tsunami, a gigantic sea wave, was caused by a submarine slide from the Norwegian continental slope. It reached Litjvatnet, today located 24 m a.s.l., but was not traced in Storkuvatnet at 30 m a.s.l. This event happened about 7200 years B.P. 相似文献