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1.
We have analyzed core MD01-2392, ∼ 360 km east of the Mekong River mouth in the South China Sea (SCS). Over the past 500 ka, planktonic foraminiferal oxygen-isotopic values are consistently lighter than northern SCS and open-ocean records by up to 0.5‰, indicating the influence of run-off from the Mekong River during both glacial and interglacial periods. Carbonate content is higher during interglacials; sedimentation rates were higher during glacials. Increased sedimentation rates since 30 ka imply increased run-off during the last glacial maximum and Holocene Period. Contrary to general experience, in which it is classed as a warm species for temperature estimates, the thermocline-dwelling species Pulleniatina obliquiloculata increased its numbers during glacial periods. This implies an estuarine circulation and even brackish-water caps during glacial periods, reinforcing the sense of strong run-off. In an overall decline of warm water, the thermocline shoaled stepwise, with rapid rises across the glacial terminations. We infer that the southern SCS was opened to an influx of Indian Ocean waters through southern passages at those times of rising sea levels.  相似文献   

2.
Current models of Pleistocene fluvial system development and dynamics are assessed from the perspective of European Lower and Middle Palaeolithic stone tool assemblages recovered from fluvial secondary contexts. Fluvial activity is reviewed both in terms of Milankovitch‐scale processes across the glacial/interglacial cycles of the Middle and Late Pleistocene, and in response to sub‐Milankovitch scale, high‐frequency, low‐magnitude climatic oscillations. The chronological magnitude of individual phases of fluvial activity is explored in terms of radiocarbon‐dated sequences from the Late Glacial and early Holocene periods. It is apparent that fluvial activity is associated with periods of climatic transition, both high and low magnitude, although system response is far more universal in the case of the high magnitude glacial/interglacial transitions. Current geochronological tools do not permit the development of high‐resolution sequences for Middle Pleistocene sediments, while localised erosion and variable system responses do not facilitate direct comparison with the ice core records. However, Late Glacial and early Holocene sequences indicate that individual fluvial activity phases are relatively brief in duration (e.g. 102 and 103 yr). From an archaeological perspective, secondary context assemblages can only be interpreted in terms of a floating geochronology, although the data also permit a reinvestigation of the problems of artefact reworking. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

3.
华北区第四纪植被演替与气候变化   总被引：6，自引：0，他引：6       下载免费PDF全文
周昆叔 《地质科学》1984,(2):165-172
文中华北区是指燕山、辽南一线以南、吕梁山以东、渭河谷地与准阳丘陵以北地区。该区属暖温带,即蒙古和东北寒温带、温带区域与华中和华东亚热带区域之间的过渡地带,故第四纪冰期、间冰期气候的变化,对本区的影响表现得很强烈,它引起第四纪植被的明显演替,是我国第四纪植被变化较大的两个区域之一(另一为青藏区)。  相似文献   

4.
Paleoclimatic changes in the late Quaternary sediments deposited in the East Sea were analyzed by studying diatoms. A total of 95 species belonging to 47 genera were identified from the Core02GHP-02 of the Ulleung Basin in the East Sea, Korea. In the Core 02GHP-02, U-Oki(169–181 cm; 9.3 ka), AT(464–465.5 cm; 22 ka) and U–Ym(556–559 cm; 33 ka) tephra layers were recognized. The chronological divisions of 02GHP-02 may be correlated with the climatic changes from the glacial interval(730–620 cm; MIS3), to interstadial(620–500 cm; MIS3), to the last glacial maximum(500–390 cm; MIS 2), to the deglaciation(390–290 cm; MIS 2), to the late glacial(290–190 cm; MIS 1), and to the Holocene(190–10 cm; MIS 1). It is speculated that diatoms were rarely found during the glacial interval when the 02GHP-02 core was deposited; during the interstadial(MIS 3) and deglaciation, a mixture of warm-water and cold-water species were found. In particular, Fragilariopsis doliolus seems to have appeared in the East Sea after 8 ka BP. In the lower layers of the Holocene deposits, cold-water species such as Neodenticula seminae were frequently found, while in the upper layers, warm-water species such as Hemidiscus cuneiformis were found in relatively large abundance. Therefore, the findings indicate that the climate became warmer during the transition from the lower layer to the upper layer of the Holocene deposits.  相似文献   

5.
南海南部普林虫与“中更新世革命”   总被引：6，自引：2，他引：4  
对南海南部ODP 1143站2.1 Ma以来沉积物中的浮游有孔虫群进行研究, 发现在冲绳海槽及南海北部普遍被认为是黑潮标志种的Pulleniatina obliquiloculata在中更新世革命(MPR)前后对冰期旋回的响应截然相反; 且在MPR之后的变化与南海北部和冲绳海槽相反, 即冰期时含量高而间冰期时低.交叉频谱分析和相位分析的结果也证实了ODP 1143站P.obliquiloculata与全球冰量变化之间的上述关系.该种在MPR前后冰期旋回的转变, 可能是由于MPR之后南海南部在冰期时切断了与印度洋之间的海水交换, 或者是冰期时海水盐度增加等因素引起的上部水体结构的重大改观所致.   相似文献   

6.
Sediments from the last interglacial (Eemian) in Jameson Land, East Greenland, and the Thule area, NW Greenland, have revealed a number of insect fragments of both arctic and more or less warmth‐demanding species. Altogether, the interglacial fauna of Coleoptera (beetles) indicates boreal conditions. Undoubtedly, a large fraction of the insect fauna succumbed when the mild Eemian climate cooled drastically during the last glacial stage. However, a group of hardy species now found far north into the High Arctic might be glacial survivors. It is, however, still puzzling why well‐adapted arctic beetle species such as Amara alpina and Isochnus arcticus did not survive the last glacial stage in Greenland. Two factors that have not been sufficiently considered when discussing survival contra extinction are the importance of microclimate and the number of sun‐hours during the Arctic summer. Even among the Coleoptera, which as a group fares quite badly in the Arctic, there might be survivors, at least among those found both during the interglacial and as fossils during the early Holocene. First of all, glacial survival applies to the seed bug Nysius groenlandicus, which was widespread during the Eemian, was found soon after the last deglaciation, and is now almost omnipresent in Greenland.  相似文献   

7.
To reconstruct the palaeoproductivity evolution history of the centre of the western Pacific warm pool (WPWP) over the last 250 ka, multi‐proxies were analysed in sediment core WP7 recovered from the Ontong–Java Plateau. Palaeoproductivity evolution at the centre of the WPWP during the last 250 ka is closely related to glacial–interglacial cycles and the insolation controlled by precession. The glacial higher primary productivity relative to the interglacial conditions could have resulted from both thermocline shoaling associated with persistent El Niňo‐like conditions and the increased influx of dust resulting from intensified winter monsoon together with important changes in the thermocline. The minimum primary productivity values during the last three terminations could be resulted from deglacial thermocline deepening and intensified stratification associated with persistent La Niña‐like conditions, and the concurrent Neogloboquadrina dutertrei δ13C minimum events probably reflect the chemical signatures of Subantarctic Mode Water and Antarctic Intermediate Water. In addition, primary productivity values are also controlled by the thermocline variations resulting from El Niño/La Niña‐Southern Oscillation processes responding to precession forcing, and lead the δ18O by about 4 ka. The 33.1 ka, 19 ka and “half‐precession” periods are prominent in the palaeoproductivity records. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

8.
白令海北部陆坡100ka来的古海洋学记录及海冰的扩张历史   总被引：4，自引：0，他引：4  
白令海北部陆坡B2-9柱状样中生源组分的研究显示, 自MIS5.3期以来表层生产力指标的粗组分和蛋白石含量呈阶梯状增加, 反映表层生产力阶段式的增长.全新世表层生产力达到最高, 并且MIS3.2~2期高, 比MIS5.3~3.3期最低.高有机碳含量对应于高C/N比值, 显示有机碳混合来源, 不能作为表层生产力的指标.MIS5.1, 3.3~3.2期和全新世高的有机碳含量和C/N比值反映间冰期陆源有机物质输入量的增加.MIS5.3期至中全新世, 不断增加的陆源砂级和粉砂级颗粒组分说明随着气候的逐渐变冷, 陆架海冰在不断扩张.伐冰碎屑和碳屑颗粒冰期、间冰段和末次冰消期升高, 而间冰期降低, 反映冰期白令海陆架海冰扩张和间冰期海冰消融的过程.冰期海冰扩张与北美大陆气候的相互关联, 揭示了晚第四纪冰期旋回中白令海海冰扩张及其对全球气候变化的响应.   相似文献   

9.
李丽  王慧  汪品先 《地球科学》2008,33(6):793-799
以分子有机地球化学为手段对南海北部四万年来的古环境古气候研究表明, U37k’-SST表层水温在冰期、间冰期平均范围分别为27℃和24℃, LGM与全新世温差达4.5℃; 以高分子量烷烃所代表的陆源物质输入和长链不饱和酮化合物所代表的海洋初级生产力都呈现冰期高、间冰期低特征, 表明冰期时陆源物质输入的增加和海洋表层生产力的提高; 正构烷烃C31/C27记录了南方大陆的植被由冰期时草本植物占优势向间冰期时木本植物占优势的转变.说明南海在末次冰期以来气候的不稳定性, 和海陆生态系统对气候变化的响应以及分子有机地球化学在古环境古气候研究中的巨大潜力.   相似文献   

10.
A pollen record from the Huelmo site (ca. 41°30′S) shows that vegetation and climate changed at millennial time‐scales during the last glacial to Holocene transition in the mid‐latitude region of western South America. The record shows that a Nothofagus parkland dominated the landscape between 16 400 and 14 600 14C yr BP, along with Magellanic Moorland and cupressaceous conifers. Evergreen North Patagonian rainforest taxa expanded in pulses at 14 200 and 13 000 14C yr BP, following a prominent rise in Nothofagus at 14 600 14C yr BP. Highly diverse, closed canopy rainforests dominated the lowlands between 13 000 and 12 500 14C yr BP, followed by the expansion of cold‐resistant podocarps and Nothofagus at ca. 12 500 and 11 500 14C yr BP. Local disturbance by fire favoured the expansion of shade‐intolerant opportunistic taxa between 10 900 and 10 200 14C yr BP. Subsequent warming pulses at 10 200 and 9100 14C yr BP led to the expansion of thermophilous, summer‐drought resistant Valdivian rainforest trees until 6900 14C yr BP. Our results suggest that cold and hyperhumid conditions characterised the final phase of the Last Glacial Maximum (LGM), between 16 400 and 14 600 14C yr BP. The last ice age Termination commenced with a prominent warming event that led to a rapid expansion of North Patagonian trees and the abrupt withdrawal of Andean ice lobes from their LGM positon at ca. 147 000 14C yr BP. Hyperhumid conditions prevailed between 16 400 and 13 000 14C yr BP, what we term the ‘extreme glacial mode’ of westerly activity. This condition was brought about by a northward shift and/or intensification of the southern westerlies. The warmest/driest conditions of the last glacial–interglacial transition occurred between 9100 and 6900 14C yr BP. During this period, the westerlies shifted to an ‘extreme interglacial mode’ of activity, via a poleward migration of stormtracks. Our results indicate that a highly variable climatic interval lasting 5500 14C years separate the opposite extremes of vegetation and climate during the last glacial‐interglacial cycle, i.e. the end of the LGM and the onset of the early Holocene warm and dry period. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

11.
Geochemical characteristics of marine sediment from the southern Drake Passage were analyzed to reconstruct variations in sediment provenance and transport paths during the late Quaternary. The 5.95 m gravity core used in this study records paleoenvironmental changes during the last approximately 600 ka. Down-core variations in trace element, rare earth element, and Nd and Sr isotopic compositions reveal that sediment provenance varied according to glacial cycles. During glacial periods, detrital sediments in the southern Drake Passage were mostly derived from the nearby South Shetland Islands and shelf sediments. In contrast, interglacial sediments are composed of mixed sediments, derived from both West Antarctica and East Antarctica. The East Antarctic provenance of the interglacial sediments was inferred to be the Weddell Sea region. Sediment input from the Weddell Sea was reduced during glacial periods by extensive ice sheets and weakened current from the Weddell Sea. Sediment supply from the Weddell Sea increased during interglacial periods, especially those with higher warmth such as MIS 5, 9, and 11. This suggests that the influence of deep water from the Weddell Sea increases during interglacial periods and decreases during glacial periods, with the degree of influence increasing as interglacial intensity increases.  相似文献   

12.
Long sediment cores (12.5 and 13.5 m) from two lakes in Yunnan Province were used to infer the paleoclimate of southwest China over the past 50,000 yr. During the Holocene and marine isotope stage (MIS 3), bio-induced carbonate precipitation and organic matter (OM) production was high, suggesting warm temperatures and high primary productivity. In contrast, sediment inorganic carbon (IC) and organic carbon (OC) concentrations were low in last glacial deposits from 38,000 to 12,000 cal yr B.P., indicating cool temperatures and low productivity. The 50,000-yr record has alternating peaks of carbonate and coarse-grain (>38 μm) quartz that reflect warm, moist interglacial or interstadial conditions alternating with cold, dry glacial or stadial conditions, respectively. Spectral analysis of the carbonate and quartz signals reveals power concentrated at periods of 7200 and 8900 cal yr, respectively, that may reflect a nonlinear climate response to precessional forcing at a time of reduced eccentricity modulation (McIntyre and Molfino, 1996). Oxygen isotope values of calcite from Yunnan lake cores indicate the summer monsoon was weak during the last glaciation from 50,000 to 12,000 cal yr B.P. The summer monsoon intensified between 12,000 and 8000 cal yr B.P., but weakened gradually in response to insolation forcing during the mid-to-late Holocene. Our results support the Overpeck et al. (1996) model that posits a weak summer monsoon during the last glaciation that responded nonlinearly to insolation forcing when its intensity was affected by Eurasian snow cover and ice-sheet extent. The summer monsoon intensified and responded linearly to seasonal insolation forcing in the Holocene when ice volume diminished.  相似文献   

13.
The Rhine catchment experienced strong changes in upstream allogenic forcing during the last 20,000 years. Climatic changes of the glacial–interglacial transition and steadily growing human impact during the second half of the Holocene forced the Rhine to adapt, resulting in changes in the fluvial morphology. The lower Rhine left two late Weichselian terraces and many Holocene palaeo-meanders in the Lower Rhine Valley (western Germany). This well-preserved terrace sequence is used to investigate the exact course of events of the lower Rhine response to changes in allogenic forcing. Five detailed cross-sections that integrate new and existing borehole data were constructed, and the deposits were analysed with regards to abandonment of terraces, changes in number of active channels, fluvial style, terrace gradients, and overbank sedimentation during the Lateglacial and Holocene. We improved and expanded the chronology of the Lower Rhine Valley deposits by dating new samples (14C, OSL), and integrated these with existing dating evidence (archaeological and historical data, cross-cutting relationships). Twice during the glacial–interglacial transition, the lower Rhine changed from braided to meandering fluvial style. During both transitional episodes (meandering) secondary channels existed alongside the main channel, with a life span up to 2500 years. The findings imply that the lower Rhine was inherently slow to complete the full morphological transition to a single thread meandering system. On specific aspects of response, the morphological response (point bar/terrace formation, contraction to a single thread) extended over relatively long periods of time, whereas discharge-related response (e.g. fluvial style change, abandonment of braidplains, channel bed lowering/incision) seems to have been near instantaneous. Reach-specific conditions determine the degree to which the geomorphic response is delayed and the complexity of the resultant morphology. Increased human-induced sediment delivery (last 2000–3000 years) is expressed as relative thicker and coarser overbank deposits in the entire study area. In the downstream part of the Lower Rhine Valley it accelerated high-stand deltaic backfilling and decreased incision. The response to human activities occurred relatively quickly in contrast to the long-term fluvial response to the glacial–interglacial transition, because the human impact mainly involved change in delivery of the suspended load.  相似文献   

14.
The coastal cliff section at Kås Hoved in northern Denmark represents one of the largest exposures of marine interglacial deposits in Europe. High‐resolution analyses of sediments, foraminifera, ostracods, and stable isotopes (oxygen and carbon) in glacial‐interglacial marine sediments from this section, as well as from two adjacent boreholes, are the basis for an interpretation of marine environmental and climatic change through the Late Elsterian‐Holsteinian glacial‐interglacial cycle. The overlying glacial deposits show two ice advances during the Saalian and Weichselian glaciations. The assemblages in the initial glacier‐proximal part of the marine Late Elsterian succession reveal fluctuations in the inflow of sediment‐loaded meltwater to the area. This is followed by faunal indication of glacier‐distal, open marine conditions, coinciding with a gradual climatic change from arctic to subarctic environments. Continuous marine sedimentation during the glacial‐interglacial transition is presumably a result of a large‐scale isostatic subsidence caused by the preceding extended Elsterian glaciation. The similarity of the climatic signature of the interglacial Holsteinian and Holocene assemblages in this region indicates that the Atlantic Ocean circulation was similar during these two interglacials, whereas Eemian interglacial assemblages indicate a comparatively high water temperature associated with an enhanced North Atlantic Current. The foraminiferal zones are correlated with other Elsterian‐Holsteinian sites in Denmark, as well as those in the type area for the Holsteinian interglacial in northern Germany and the southern North Sea. Correlation of the NW European Holsteinian succession with the marine isotope stages MIS 7, 9 or 11 is still unresolved.  相似文献   

15.
We used positive thermal ionization mass spectrometry (PTIMS) to generate high precision δ11B records in Porites corals of the mid-late Holocene from the South China Sea (SCS). The δ11B values of the Holocene corals vary significantly, ranging from 22.2‰ to 25.5‰. The paleo-pH records of the SCS, reconstructed from the δ11B data, were not stable as previously thought but show a gradual increase from the Holocene thermal optimal and a sharp decrease to modern values. The latter is likely caused by the large amount of anthropogenic CO2 emissions since the Industrial Revolution but variations of atmospheric pCO2 cannot explain the pH change of the SCS before the Industrial Revolution. We suggest that variations of monsoon intensity during the mid-late Holocene may have driven the sea surface pH increase from the mid to late Holocene. Results of this study indicate that the impact of anthropogenic atmospheric CO2 emissions may have reversed the natural pH trend in the SCS since the mid-Holocene. Such ocean pH records in the current interglacial period can help us better understand the physical and biological controls on ocean pH and possibly predict the long-term impact of climate change on future ocean acidification.  相似文献   

16.
根据南海西部越南岸外MD05-2901岩芯成对的有孔虫壳体氧同位素和U3k7′-SST计算出过去450ka以来南海西部表层海水氧同位素～δ18Owater和盐度Swater变化记录,二者的变化范围在冰期分别为0.2‰～0.6‰和34.2‰～35.1‰,间冰期分别为-0.6‰～0和32.4‰～33.7‰,表现为冰期高、间冰期低的特征。相反扣除冰盖影响后的剩余氧同位素～δ18Oresid和剩余盐度Sresid,呈现冰期低、间冰期高的特征,在冰期分别平均为-0.5‰和32.7‰,间冰期分别平均为-0.3‰和33.1‰。研究认为该现象主要与赤道太平洋海域冰期纵向的ITCZ平均位置偏南导致的降雨增加有关,同时冰期温度低蒸发弱,间冰期温度高蒸发强以及冰期海平面下降,南海地理格局的改变、河流输入增多等因素也有一定影响。  相似文献   

17.
Middle Pleistocene to Holocene sediment variations observed in a 26 metre long core taken during a cruise of the RV Marion Dufresne are presented. Core MD992202 was retrieved from the northern slope of Little Bahama Bank and provides an excellent example for sedimentation processes in a mid‐slope depositional environment. The sediment composition indicates sea‐level related deposition processes for the past 375 000 years (marine isotope stages 1 to 11). The sediments consist of: (i) periplatform ooze (fine‐grained particles of shallow‐water and pelagic origin) with moderate variations in carbonate content, carbonate mineralogy and grain‐size; and (ii) coarser intervals with cemented debris consisting of massive, poorly sorted, mud‐supported or clast‐supported deposits with an increased high‐magnesium calcite content. During interglacial stages (marine isotope stages 1, 5, 7, 9 and 11) periplatform oozes (i) are characterized by higher aragonite contents, finer grain‐size and higher organic contents, whereas during glacial stages (marine isotope stages 2 to 4, 6, 8 and 10), increased low‐magnesium and high‐magnesium calcite values, coarser grain‐size and lower organic contents are recorded. These glacial to interglacial differences in mineralogy, grain‐size distribution and organic content clearly show the impact of climatically controlled sea‐level fluctuations on the sedimentation patterns of the northern slope of Little Bahama Bank. The coarser deposits (ii) occur mainly at the transitions from glacial to interglacial and interglacial to glacial stages, and are interpreted as redeposition events, indicating a direct link between sediment properties (changes in mineralogy, grain‐size distribution, variations in organic contents) and sea‐level fluctuations. Changes in hydrostatic pressure and the wave base position during sea‐level changes are proposed to have triggered these large‐scale sediment redepositions.  相似文献   

18.
文章讨论了南黄海泥质区、东海陆架及冲绳海槽北部表层沉积物和柱状岩芯中10 Be及9 Be含量的水平和垂直分布,并与重金属Pb的分布进行了比较。表层沉积物中的10 Be,9 Be和Pb三者表现出完全不同的分布特征。10 Be的分布主要受黑潮及其支流黄海暖流所支配; 9 Be的分布受黄河陆源物质输入的影响,主要集中在南黄海泥质区; Pb则主要分布在长江口和琉球群岛附近,反映了人类活动的影响。冲绳海槽北部末次冰期和全新世时10 Be的沉积通量变化在整体上反映了10 Be大气生产率的变化,即地球磁场屏蔽效应的影响。03孔全新世时10 Be的沉积通量 (1.12×109atoms/cm2ka)基本上等于10 Be的现代大气平均生产率,而在末次冰期时平均为4.06×109atoms/cm2ka, 高于10 Be 的现代大气平均生产率3倍以上。在冲绳海槽由于黑潮的缘故,10 Be对气候的变化响应要比极地冰芯的10 Be变化响应灵敏的多,对气候变化信号起了放大的作用。冰期时冲绳海槽北部10 Be的沉积通量远远高于太平洋大洋海区,充分反映了黑潮的传送带作用和边缘海的聚焦沉积作用,并表明末次冰期时在千年尺度上黑潮仍流经冲绳海槽,且强度并未减弱。 10 Be的通量在新仙女木时降到整个岩芯所跨时期的最低点,甚至低于10 Be的现代大气平均生产率,因此推测在新仙女木事件时,黑潮的变动特别大,有可能改向或断流。  相似文献   

19.
The transition from the last glacial and beginning of Bølling–Allerød and Pre‐Boreal periods in particular is marked by rapid increases in atmospheric methane (CH4) concentrations. The CH4 concentrations reached during these intervals, ～650–750 ppb, is twice that at the last glacial maximum and is not exceeded until the onset of industrialization at the end of the Holocene. Periods of rapid sea‐level rise as the Last Glacial Maximum ice sheets retreated and associated with ‘melt‐water pulses’ appear to coincide with the onset of elevated concentrations of CH4, suggestive of a potential causative link. Here we identify and outline a mechanism involving the flooding of the continental shelves that were exposed and vegetated during the glacial sea‐level low stand and that can help account for some of these observations. Specifically, we hypothesize that waterlogging (and later, flooding) of large tracts of forest and savanna in the Tropics and Subtropics during the deglacial transition and early Holocene would have resulted in rapid anaerobic decomposition of standing biomass and emission of methane to the atmosphere. This novel mechanism, akin to the consequences of filling new hydroelectric reservoirs, provides a mechanistic explanation for the apparent synchronicity between rate of sea‐level rise and occurrence of elevated concentrations of ice core CH4. However, shelf flooding and the creation of transient wetlands are unlikely to explain more than ～60 ppb of the increase in atmospheric CH4 during the deglacial transition, requiring additional mechanisms to explain the bulk of the glacial to interglacial increase. Similarly, this mechanism has the potential also to play some role in the rapid changes in atmospheric methane associated with the Dansgaard–Oeschger cycles. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

20.
On- and off-mound sediment cores from Propeller Mound (Hovland Mound province, Porcupine Seabight) were analysed to understand better the evolution of a carbonate mound. The evaluation of benthic foraminiferal assemblages from the off-mound position helps to determine the changes of the environmental controls on Propeller Mound in glacial and interglacial times. Two different assemblages describe the Holocene and Marine Isotope Stage (MIS) 2 and late MIS 3 (∼31 kyr BP). The different assemblages are related to changes in oceanographic conditions, surface productivity and the waxing and waning of the British Irish Ice Sheet (BIIS) during the last glacial stages. The interglacial assemblage is related to a higher supply of organic material and stronger current intensities in water depth of recent coral growth. During the last glaciation the benthic faunas showed high abundances of cassidulinid species, implying cold bottom waters and a reduced availability of organic matter. High sedimentation rates and the domination of Elphidium excavatum point to shelf erosion related to sea-level lowering (∼50 m) and the progradation of the BIIS onto the shelf. A different assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species are only found or show significantly higher relative abundances in on-mound samples and their maximum contribution in the lower part of the record indicates a higher coral growth density on Propeller Mound in an earlier period. They are less abundant during the Holocene, however. This dataset portrays the boundary conditions of the habitable range for the cold-water coral Lophelia pertusa, which dominates the deep-water reefal ecosystem on the upper flanks of Propeller Mound. The growth of this ecosystem occurs during interglacial and interstadial periods, whereas a retreat of corals is documented in the absence of glacial sediments on-mound. Glacial conditions with cold intermediate waters, a weak current regime and high sedimentation rates provide an unfavourable environmental setting for Lophelia corals to grow. A Late Pleistocene decrease is observed in the mound growth for Propeller Mound, which might face its complete burial in the future, as it already happened to the buried mounds of the Magellan Mound province further north.  相似文献   

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