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1.
OTTO SALVIGSEN ANNE ELGERSMA CHRISTIAN HJORT ERIK LAGERLUND OLAV LIESTØL NILS-OLOF SVENSSON 《Polar research》1990,8(2):261-273
Traces of former glaciation were studied on Erdmannflya and Bohemanflya. Both peninsulas were probably completely covered by glaciers during the Late Weichselian and the final dcglaciation took place around years BP. Esmarkbreen readvanced shortly after 9,500 BP, probably a local and shortlasting event. Raised beaches occur to about 60 m above sea level, and date back to about 10,000 BP. Initial land emergence was rapid, about 3m/100 years. It seems to have been followed by a marine transgression between 8,500 and 7,500 BP, which resulted in a large and distinct beach bridge and marine abrasion cliffs about 10-12 m above present sea level. Mytilus edulis lived in the area between at least 9.000 and 5,000 BP. Five thousand years ago relative sea level probably stood 3-4 m higher than today. Relative sea level has remained close to present during the last centuries. Different positions of glacier fronts in this century have also been mapped. 相似文献
2.
Stratigraphic and Morphologic Constraints on the Weichselian Glacial History of Northern Prins Karls Forland, Western Svalbard 总被引：1，自引：0，他引：1
Torbjörn Andersson Steven L. Forman Ólafur Ingólfsson & William F. Manley 《Geografiska Annaler: Series A, Physical Geography》2000,82(4):455-470
Uncertainty remains if ice–free marginal areas existed on the west coast of Svalbard during the Late Weichselian. Field mapping and correlation to well dated raised beach sequences on nearby Brøggerhalvøya reveal the existence of two generations of raised beach deposits on northern Prins Karls Forland. Distinct beach ridges rise up to the inferred Late Weichselian marine limit at 18 m a.s.l. Discontinuous pre–Late Weichselian beach deposits rise from the Late Weichselian marine limit up to approximately 60 m a.s.l. Expansion of local glaciers during the Late Weichselian is indicated by the limited distribution of a till that overlies parts of the older beach sequence. Stratigraphic data and chronological control indicate deposition in a shallow marine environment before 50 ka bp . Correlation to stratigraphic sites on western Svalbard suggests deposition at c . 70 ±10 ka. Glaciotectonic structures disclose expansion of local glaciers into the For–landsundet basin during stage 4 or late stage 5 high relative sea level. Palaeotemperature estimates derived from amino acid ratios indicate that during the time interval c . 70 to 10 ka the area was exposed to cold subaerial temperatures with low rates of racemization. Pedogenesis and frost–shattered clasts at the contact between c . 70 ka deposits and Holocene deposits further indicate a prolonged period of subaerial polar desert conditions during this time interval. The evidence suggests that the Barents Sea ice sheet did not extend across northern Prins Karls Forland during the Weichselian. It is inferred that during the Late Weichselian, ice was drained throughout the major fjords on the west coast of Svalbard and that relatively large marginal areas experienced polar desert conditions and minor expansions of local glaciers. 相似文献
3.
The Barents Sea ice sheet - a sedimentological discussion 总被引：1，自引：0，他引：1
Sediment sampling and shallow seismic profiling in the western and northern Barents Sea show that the bedrock in regions with less than 300 m water depth is unconformably overlain by only a thin veneer (<10 m) of sediments. Bedrock exposures are probably common in these areas. The sediments consist of a Holocene top unit, 0.1–1.5 m in thickness, grading into Late Weichselian glaciomarine sediments. Based on average sedimentation rates (14 C-dating) of the Holocene sediments, the transition between the two units is estimated to 10,000–12,000 B.P. The glaciomarine sediments are commonly 1–3 m in thickness and underlain by stiff pebbly mud, interpreted as till and/or glaciomarine sediments overrun by a glacier. In regions where the water depth is over 300 m the sediment thickness increases, exceeding 500 m near the shelf edge at the mouth of Bjørnøyrenna. In Bjømøyrenna itself the uppermost 15–20 m seem to consist of soft glaciomarine sediments underlain by a well-defined reflector, probably the surface of the stiff pebbly mud. Local sediment accumulations in the form of moraine ridges and extensive glaciomarine deposits (20–60m in thickness) are found at 250–300m water depth, mainly in association with submarine valleys. Topographic highs, probably moraine ridges, are also present at the shelf edge. Based on the submarine morphology and sediment distribution, an ice sheet is believed to have extended to the shelf edge at least once during the Pleistocene. Spitsbergenbanken and the northern Barents Sea have also probably been covered by an ice sheet in the Late Weichselian. Lack of suitable organic material in the glacigenic deposits has prevented precise dating. Based on the regional geology of eastern Svalbard, a correlation of this younger stage with the Late Weichselian is indicated. 相似文献
4.
香港地区晚第四纪环境的几个问题 总被引：6，自引：0，他引：6
香港的“潜在”植物区系及顶极植被与爪哇及印度相似。香港的红树林组成逊于海南但胜于闽南。Ｑ３＾２海相层中有现今仅见于海南的陆均松和海松。Ｑ４海相层中有红茄冬、角果木、榄李，而现今仅见榄李。中全新世香港有海滩岩发育。上述现象表明香港属于热带北部，历史上热带性比今更强。香港及邻近海域１１个剖面揭示Ｑ３＾１以来有３个海相层，经历３次重大的海陆变迁。据验潮记录，近三四十年海平面上升率为１．６４±０．２５ｍｍ 相似文献
5.
Three radiocarbon dates on marine organic material from southernmost Spitsbergen are presented, making it possible to compare the Holocene shoreline displacement in this area with that of other areas of Svalbard. The most distinct raised beach feature is the large beach ridge terrace about 10 m above sea level which most probably is the result of a marine transgression ca. 6500 years ago. Dating of 2700-year-old laminaria from about 2 m above sea level demonstrates a small rising of the land during the youngest Holocene. 相似文献
6.
下辽河平原和辽东半岛海岸带晚更新世以来的海侵 总被引：12，自引：2，他引：10
本文根据钻孔资料、14C测年数据、微体古生物及孢粉组合特征,讨论了研究区晚更新世以来海侵的次数、规模、时间以及岸线变化。 相似文献
7.
Open sections along Kongsfjodhallet, the north-western coast Kongsfjorden, Svalbard, exhibit marine and glacigenic sediments of Early to Late Plestocene age. Glaciatio, deglaciation and subsequent isostatic rebound caused the formation of three sedimentary successions (A, B and C) that comprise till grading upward into glaciomarine mud, followed by shell-bearing sand, and finally littoral sand and gravel. Six major lithostratigraphic units are recognized. Succession C comprises units 1 and 2, which were deposited during an Early Pleistocene glaciation, followed by deglaciation and subsequent beach progradation. Succession B is divisible into units 3 and 4 and reflects glaciation and eventual emergence as a result of isostatic response. The youngest succesion (A) comprises units 5 and 6, and reflects fiord glaciation followed by a regression during an Early Weichselian glaciation-deglaciation episode. Ice-free conditions may have prevailed untill the Late Weichselian, when a glaciation, confined to the fiord trough, covered parts of Kongsfjordhallet. Deglaciation and isostatic rebound are recorded by Holocene marine terraces up to ca 40 m a. s. l.
Marine and glacial events from Kongsfjordhallet are compared with stratigraphic evidence from adjacent regions and it is suggested that the Late Weichselian ice configuration was of a more restricted nature than proposed by previous authors. Glaciers. draining through the larger ford troughs reached the shelf break. while at the same time other parts of western Svalbard could have experienced restricted glaciation. 相似文献
Marine and glacial events from Kongsfjordhallet are compared with stratigraphic evidence from adjacent regions and it is suggested that the Late Weichselian ice configuration was of a more restricted nature than proposed by previous authors. Glaciers. draining through the larger ford troughs reached the shelf break. while at the same time other parts of western Svalbard could have experienced restricted glaciation. 相似文献
8.
An emergence curve based on nine radiocarbon dated samples of mosses, shells, whale bones and driftwood has been constructed for Agardhbukta. Beach sediments and delta deposits were found up to c. 50 m above sea level, and the oldest date goes back to about 10, 000 yrs BP. However, the possibility of a higher marine limit cannot be excluded. The Agardhbukta curve shows a nearly linear uplift during the entire Holocene. It differs from the western Spitsbergen curves, where a transgression occurs, and is more similar to curves from areas further east in the Svalbard archipelago. 相似文献
9.
东南极大陆沿岸的维斯特福尔德丘陵(68°22'～68°40'S,77°55'～78°30'E)和西南极乔治王岛南端的菲尔德斯半岛(62°08'～62°20'S,58°45'～58°58'W)的气候条件不同。前者属于极地大陆性气候,气温低,冬季严寒,干燥、风大,夏季较短;后者属于极地海洋性气候,气温不很低,湿润、风小,夏季较长。因此,两地的冰缘地貌的组合类型及其发育过程存在明显的差异。前者冰缘地貌单一,发展速度较慢;后者冰缘地貌复杂多样,发展速度较快。 本文根据实地观测资料,对极地大陆型和极地海洋型两类冰缘地貌作一些比较,并且提出,年冻融日数是决定冰缘作用强弱的最重要指标。 相似文献
10.
在回顾南海北部海岸和陆架地层证据的基础上,梳理了珠江三角洲晚第四纪演变历史。结果显示：1）本区晚第四纪地层拥有2套海相沉积,上（新）海相层是当前间冰期（或10.5 ka B.P.以来）高海平面期间形成的沉积物,而下（老）海相层最可能是末次间冰期（126―120 ka B.P.）高海平面阶段留下的沉积物;2）老海相层顶面埋深在三角洲盆地内至少比现今海平面低10~15 m,在珠江口一带则低于20 m,这说明珠江三角洲盆地存在构造沉降,因为2次间冰期的海平面高度是相近的;3）在新生代欧亚板块大陆向东南伸展的构造格局下,南海北部陆架和海岸带经历长期连续的沉降,而长期平均沉降率在0.12 mm/a左右,明显低于GPS测出的现代沉降率;4）在这种板块运动基础上,晚第四纪断裂活动增强了三角洲盆地的沉降,为2次海侵提供了可容沉积空间。 相似文献
11.
Tertiary and Quaternary deposits outcrop in the coastal cliff of Balanusviken at Sarsbukta in Vest-Spitsbergen. The Tertiary deposits appear by their foraminifera to belong to the Middle to Upper Oligocene. The Quaternary deposits consist of an upper part of Late Pleistocene to Holocene age, and a lower part which had previously been considered Middle Weichselian of age. Its foraminiferal assemblages suggest a higher age (Late Saalian, Eemian?). This lower part of the Quaternary deposits is related to a series of raised beaches with an upper limit at SO m above present day sea level. They were probably formed during the Eemian, and have not been distorted by later glaciation. The present study is based on sediment samples collected from the coastal cliff of Balanusviken, and particularly from that of Balanuspynten, Sarsbukta, Spitsbergen, during the summer expedition of Norsk Polarinstitutt in 19Sø. 相似文献
12.
为了深入探讨珠江三角洲的沉积古环境和古气候历史,在三水市区获取了2个高取芯率的钻孔岩芯,进行了12个AMS 14C测年,并结合孢粉、硅藻等分析结果探讨三水地区全新世的海平面与河流水动力变化,以及古植被演替过程。结果表明：钻孔所在区域全新世沉积总体从9 000 cal. a B.P.左右开始,呈现河流相―河湾相―河口湾相―潮坪相―河口湾相―河漫滩相的演变过程。三水区的早全新世沉积阶段年代最早为9 000 cal. a B.P.左右,表现为河口湾相的淤泥质粉砂沉积,硅藻以淡水种类为主,最高沉积速率为1.6 cm/a。海侵初始时间为8 700 cal. a B.P.左右,最高海平面时间为7 600 cal. a B.P.左右,此时海岸带发育红树林,丘陵山地发育较茂盛的亚常绿热带常绿阔叶林;中―晚全新世阶段（6 500―2 200 cal. a B.P.）,以泥炭粉砂沉积为主,沉积速率为0.2~0.5 cm/a,河口区高潮线附近及河流弯道低洼滩地在5 000 cal. a B.P.前后形成淡水沼泽、河口三角洲边缘区洼地水松林发育。在晚全新世（2 200 cal. a B.P.左右）以来,陆相黏土质沉积指示河口泥沙快速堆积,三角洲平原迅速扩大,沉积速率高达1.7 cm/a。孢粉结果显示次生的芒箕孢子剧增,陆地植被稀疏,人类活动显著增强。 相似文献
13.
Age determinations of bivalve shells indicate that Bockfjorden, a fjord in north-western Spitsbergen, Svalbard, was deglaciated shortly before 10 Kya, and that the upper marine limit in this area, with an altitude of about 50 m a.s.l., has the same age. During most of the Holocene, the glaciers in Bockfjorden were less extensive than they are today. Their maximum Holocene extension occurred during the Little Ice Age. The initial shoreline emergence after the deglaciation was rapid, and former shorelines younger than 8.5 Ky are below the present sea level. A mid-Holocene transgression of the sea is traced as well as a transgression during the last thousand years. 相似文献
14.
With the purpose of studying the vegetation and climatic changes in the last millenia of the Coastal Plain of Rio Grande do Sul, Brazil, a palynological study was made of the sediments of the northern part of Lagoa dos Patos lagoon. Twenty-four samples from a 2.26 m core taken at a depth of 7.70 m (30° 50 50 S and 50° 59 05 W) were collected.The analyses revealed marine transgression at 5170±120 years B.P., giving rise to local vegetation consisting chiefly of xerophytes and halophytes. Vegetation characteristic of a humid environment was present along adjacent portions of the Coastal Plain at this time. Transgression increased at about 4080±110 years B.P., when the greatest level of tidewater was reached. This coincided with the beginning of forest vegetation development along the inner portions of the Coastal Plain. These data suggest that marine transgression may have been a consequence of higher temperatures and more humidity. After 4000 years B.P., regression occurred, resulting in fresh waters characteristics in the northern portion of the lagoon. The development of forest vegetation began at this time.This is the fourth in a series of papers published in this issue on Paleolimnology in Southern South America. Dr. C. A. Fernández served as guest editor for these papers. 相似文献
15.
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
16.
JON Y. LANDVIK CHRISTIAN HJORT JAN MANGERUD PER MOLLER OTTO SALVIGSEN 《Polar research》1995,14(2):95-104
The eastern part Svalbard archipelago and the adjacent areas of the Barents Sea were subject to extensive erosion during the Late Weichselian glaciation. Small remnants of older sediment successions have been preserved on Edgeeya, whereas a more complete succession on Kongsøya contains sediments from two different ice-free periods, both probably older than the Early Weichselian. Ice movement indicators in the region suggest that the Late Weichselian ice radiated from a centre east of Kong Karls Land. On Bjørnøya, on the edge of the Barents Shelf, the lack of raised shorelines or glacial striae from the east indicates that the western parts of the ice sheet were thin during the Late Weichselian. The deglaciation of Edgeøya and Barentsøya occurred ca 10,300 bp as a response to calving of the marine-based portion of the ice sheet. Atlantic water, which does not much influence the coasts of eastern Svalbard today, penetrated the northwestern Barents Sea shortly after the deglaciation. At that time, the coastal environment was characterised by extensive longshore sediment transport and deposition of spits at the mouths of shallow palaeo-fjords. 相似文献
17.
珠江三角洲生物埋葬群与环境变迁 总被引：6，自引：0，他引：6
本文将珠江三角洲第四纪环境与现代环境的生物埋葬群进行对照，重建晚更新世中期和全新世中期的古沉积环境，划分出两期的海侵区、海侵波及区、海侵影响区。并对中更新世海侵期表示存疑。 相似文献
18.
广东黄圃镇海蚀遗址的形成年代及古地理环境 总被引：1，自引：0，他引：1
广东中山市黄圃镇海蚀遗址是广东沿海至今为止所发现最大规模的海蚀遗址之一,古海蚀地貌延伸范围超过200米,海蚀洞、海蚀崖、海蚀平台等海蚀地貌仍保持得较为完好。根据地形特征、地层（钻孔）资料、海侵范围、史料记载进行综合确定了古海蚀遗址的形成年代和古地理环境。古海蚀崖所在的尖峰山由白垩系陆相红色碎屑岩系构成。黄圃附近地区在晚更新世末期第一次海侵前已经是一隆起地块,在晚更新世和全新世两次海侵时都处在较高的位置,出露的白垩系地层（尖峰山）为蚀余的低矮山地。这些残余山地在全新世海侵大部分时段内为珠江口古海湾中的岛屿,黄圃镇作为大陆岸线的时间很短,海蚀地形主要形成于晚全新世前海侵时（距今约6100～1600年）的岛屿时期。 相似文献
19.
长江三角洲长江以北地区全新世以来人地关系的环境考古研究 总被引：14，自引：10，他引：14
通过长江三角洲长江以北地区高邮龙虬庄和海安青墩两个新石器时代考古遗址剖面粒度、磁化率、孢粉以及年代学测定，较为全面地分析了该区全新世以来生态环境变化与人类文明兴衰的相互关系，研究结果表明：在有人类活动以前，该区距离海洋较远，但受海面变化影响强烈。此后，气候向暖湿方向发展，7000—6000间的大西洋温暖湿润气候以及3700aB．P．左右期间，该区气候适宜，人类文明在这样的适宜气侯条件下得到长足发展。值得注意的是，海安青墩遗址剖面中出现厚达1m多的自然沉积地层，粒度分析以及孢粉分析表明，这一自然沉积地层是4000aB．P．以来的海侵事件所致，正是这次海侵事件，使研究区人类文明得以衰落。 相似文献
20.
通过对珠江口岛屿小型海湾如珠海淇澳岛和澳门黑沙滩一级阶地上的古沙坝/沙丘进行光释光（OSL）年代测定、粒度分析,结果表明,全新世潮间带砂体沉积的底部年代根据光释光测年结果和沉积速率推算,超过9 ka。海岸带形成的古沙坝或风成砂质沉积的光释光测年结果大部分老于新石器文化堆积的器物年代,表明全新世高海面期砂质滨海相沉积的形成先于新石器人类活动遗迹。潮间带砂质滨海相沉积的上覆地层常在6.5 ka左右快速转变为潮上带的风成沉积-人类活动混合堆积,导致文化层中沉积物粒度分选变差,参数波动较大。淇澳岛小沙澳湾9―4.3 ka的滨海相砂质沉积的顶部目前位于海拔＋4.8 m,这一高程可能与构造抬升运动有关。 相似文献