Glacial activity in New Zealand near the Pleistocene-Holocene boundary in the light of new radiocarbon dates

Burrows, C. J., Chinn, T. & Kelly, M. 1976 08 01: Glacial activity in New Zealand near the Pleistocene-Holocene boundary in the light of new radiocarbon dates.
Although glaciers in New Zealand were diminishing from the late Pleistocene onwards, there remained an extensive ice cover, greater than at present, well into early Holocene. The Birch Hill advances are dated to just before the Pleistocene-Holocene boundary at 10,000 B.P., and at least two lesser advances are recognised, at 9000 B.P. and 8000 B.P. A general parallel with northern hemisphere glacial activity is drawn.     

Large earthquakes and the abandonment of prehistoric coastal settlements in 15th century New Zealand

This paper reports on the effects of large earthquakes and related events, such as tsunamis, on prehistoric coastal settlements in New Zealand. It is based on field observations at several well‐established archaeological sites around the Cook Strait region and on literature reviews. We identify three broad periods of seismic activity in New Zealand since human occupation of the islands: 13th century, 15th century, and the 1750s to 1850s. The most significant, from a prehistoric human perspective, is the 15th century. Using examples from the Cook Strait region, we suggest that the abandonment of coastal settlements, the movement of people from the coast to inland areas, and a shift in settlement location from sheltered coastal bays to exposed headlands, was due to seismic activity, including tsunamis. We expect similar patterns to have occurred in other parts of New Zealand, and other coastal areas of the world with longer occupation histories. © 2003 Wiley Periodicals, Inc.     

Resurrecting beach ridge archaeology: Parallel depositional records from St. Lawrence Island and Cape Krusenstern,Western Alaska

Archaeological sites on gravel beach ridge plains offer a treacherously facile method of reconstructing cultural chronology based on the assumption that settlements were preferentially situated nearest the sea. the initial phase of beach ridge methodology in Alaska dates from its 1930s use by Henry Collins at St. Lawrence Island and its 1950s use by Louis Giddings in Kotzebue Sound. Numerous questions of cultural and depositional chronology remain unresolved. At Gambell, on St. Lawrence Island, three sets of ridges span the period since about 2000 B.P., with a prominent disconformity after Punuk culture times at ca. 1100 B.P. Reviewing the ¹⁴C dates (n = 83) we find that the Gambell sequence (n = 50) broadly parallels that of Kotzebue Sound, especially in the similar erosional disconformity at 1200-1000 B.P., related to increased storminess in the North Pacific. the Cape Krusenstern sequence is only loosely constrained by ¹⁴C dates (n = 33) disproportionately concentrated on 7 of the 114 ridge fragments. the dating of early Choris culture is especially problematic, which seems to occur both before and after the Old Whaling culture, well-dated at 2900-2800 B.P. on the 53rd ridge. However, reanalyzing the depositional sequence, we find that some of the more easterly Choris ridges probably represent erosional events after the Old Whaling occupation.     

Early agriculture in the Eastern Grand Canyon of Arizona,USA

Abandoned fields in Colorado River alluvium in the eastern Grand Canyon show signs of primitive agriculture. Presence of maize pollen in association with buried soils near Comanche Creek suggests that farming began prior to 3130 yr B.P. Cotton pollen, identified in buried soils near Nankoweap Creek, dates to 1310 yr B.P., approximately 500 years earlier than previously reported anywhere on the Colorado Plateau. Farming spanned three millennia in this reach of the canyon. Entrenchment, starting approximately 700 yr B.P., making water diversion to fields infeasible, was likely responsible for field abandonment. © 2000 John Wiley & Sons, Inc.     

Evidence for a postglacial low relative sea-level stand in the drowned delta of the Merrimack River, Western Gulf of Maine

A submerged delta of the Merrimack River, located offshore between Cape Ann, Massachusetts, and the New Hampshire border, indicates a postglacial low relative see-level stand of about −47 m. The low stand is inferred to date to 10,500 yr B.P., but a lack of age control makes this assignment uncertain. A curve based on a late Wisconsinan, high relative sea-level stand of +32m at 13,000 yr B.P., a low stand of −47m at 10,500 yr B.P., and younger radiocarbon dates related to sea-level rise indicates an early postglacial crustal rise of at least 5 m per century.     

Holocene gelifluction in a snow-patch environment at the Forest-Tundra Transition along the eastern Hudson Bay Coast, Canada

The Holocene chronology of gelifluction events in a snow-patch environment of the Richmond Gulf area, eastern Hudson Bay Coast (northern Québec), has been constructed using sixty radiocarbon-dated buried organic horizons. The samples were recovered from nine soil trenches located along an altitudinal gradient associated with a chronosequence as determined by the regional land emersion curve. The most significant gelifluction activity occurred after c. 2,800 B. P. Gelifluction events occurred around 5,600, 5,000, 4,500, 3,150, 2,500, 1,550, 1,200 and 450 B.P., and at present. According to the frequency of ¹⁴C dates. gelifluction has been particularly active between 2,800-2,300, 1,700–900 and 600-300 B.P., and at present. Gelifluction occurrence seems to be closely related to well-bracketed cold episodes in northern Québec. The increase in frequency of ¹⁴C dates associated with burial of organic matter through gelifluction after c. 2,800 B. P. substantiates the colling trend depicted elsewhere, both in northern Québec and in the northern hemisphere.     

山西运城盆地北部峨嵋台地晚更新世—全新世地质环境变化及其对人类聚落分布的影响

新构造运动及自然环境的变化深刻影响着人类聚落的形成与分布.山西运城盆地北部的峨嵋台地中段自北向南发育孤山隆起、埝底洼地、三管高地,现今人类聚落在相对平坦的埝底洼地中较少,而是围绕低洼地带周缘斜坡带分布.野外地质调查发现,研究区广泛分布的马兰黄土之上覆盖着一套冲洪积物、湖相沉积及河流相沉积.文章对不同地貌部位典型剖面开展...     

Radiocarbon dating of Danube Delta deposits

The Holocene history of the Danube Delta has been studied using ¹⁴C analyses of faunal material. The principal phases of development include: (1) initial Letea Caroarman spit, 11,700–9800 yr B.P. in its central part, 8800-5500 yr B.P. in its southern part; (2) Sf. Gheorghe I Delta, 8900-7200 yr B.P.; (3) Sulina Delta, 7200-2000 yr B.P., and (4) Sf. Gheorghe II Delta-Chilia Delta 2000 yr B.P.-present. Other smaller-scale features have also been dated, including secondary deltas (Co?na and Sinoe Deltas) and littoral bars. Age determinations carried out on whole samples were erratic and it was found that individual species had to be separated and dated. In all cases, the older dates were of transported material whereas the younger dates gave the true age of the formation.     

Vegetation and climates in southern Tasmania since the last glaciation

Enclosed basins (glacial and nonglacia) of Tasmania contain the most comprehensive record in Australia of trends in a regional vegetation and climate since the late Pleistocene. Seven pollen sequences, each continuous and extending back at least 10,000 years, are used to reconstruct the history of postglacial vegetation and climate in Southern Tasmania (42°S–43°30′S). Interpretations are supported by a study of the modern pollen rain. Postglacial climates in Tasmania were characterized by a strong west-to-east decrease in precipitation. During the late Pleistocene, climates were markedly colder and drier than at present, and the vegetation was largely devoid of trees. A major rise in temperature between ca. 11,500 and 9500 yr B.P., accompanied by rising effective precipitation, resulted in the expansion of Eucalyptus, then other trees, across Tasmania. This warming trend may have been temporarily reversed during the early postglacial. Dry climates delayed the development of forest in inland eastern Tasmania until after ca. 9500 yr B.P. There is no evidence for a major change in climate since this temperature rise. Two broad phases of development have occurred within the postglacial forests. The first was an early Holocene phase during which Nothofagus cunninghamii cool temperate rain forest developed in western Tasmania and on the slopes of mountains in central and southeastern Tasmania. Eucalyptus sclerophyll forests developed in eastern Tasmania and have remained dominant there since. By ca. 7800 yr B.P. rain-forest communities were established beyond present-day limits. The second phase was a mid to late Holocene phase during which forests and alpine vegetation became more open in structure, leading to the re-expansion of Eucalyptus and shade-intolerant species. During the early to mid Holocene, climates in Southern Tasmania were wetter and (? then) warmer than at present. Maximum and minimum dates for this “optimum” are 8000 and 5000 yr B.P. Since then, climates have become increasingly rigorous, possibly through an increased incidence of inequable “weather types” leading to an increase in the frequency of drought and frost. Structural changes in the postglacial vegetation of Southern Tasmania closely parallel those at equivalent latitudes in New Zealand and Chilean South America, hence are likely to reflect the same primary cause.     

Paleolithic burnt bone horizons from the Swabian Jura: Distinguishing between in situ fireplaces and dumping areas

Hohle Fels Cave is one of several Upper Paleolithic sites on the eastern extension of the Swabian Alb in southwestern Germany. Several phases of excavations have been conducted since 1870. The archaeological inventories comprise a broad range of artifacts produced from stone, bone, teeth, ivory, and antler. The site has also yielded Paleolithic rock art, sculpture, and engravings. The Pleistocene inventories unearthed so far belong to the Magdalenian, Gravettian, and Aurignacian; Middle Paleolithic horizons may well be uncovered as excavations continue. The chronology of three main occupation phases has been established with numerous ¹⁴C measurements. The Magdalenian dates to about 13,000 yr B.P., and the richest Gravettian deposit contains a burnt bone‐layer extending over ca. 12 m² that dates to about 29,000 yr B.P. The underlying Aurignacian horizons predate 30,000 yr B.P. The Gravettian burnt bone layer (archaeological layer IIcf) is a key horizon because of its distinct composition and color and its large horizontal extension. Layer IIcf has been examined using a combination of analytical techniques including micromorphological analysis of thin sections with polarizing light microscopy and scanning electron microscopy for fabric and identification of mineral and biogenic constituents. The bone mineral composition was analyzed by Fourier transform infrared spectroscopy (FTIR) and electron probe microanalytical techniques. These investigations in tandem with the field observations indicate intense burning of bones as fuel. The micromorphological and contextual archaeological data suggest that layer IIcf is a secondary dump rather than an in situ accumulation. This deposit and other Paleolithic burnt deposits in the Swabian Jura appear to reflect intense periods of winter occupation in these caves. © 2003 Wiley Periodicals, Inc.     

Holocene ethnobotanical and paleoecological record of human impact on vegetation in the Little Tennessee River Valley, Tennessee

Human occupation and utilization of plant resources have affected vegetation in the lower Little Tennessee River Valley of East Tennessee for 10,000 yr. Changes in Indian cultures and land use are documented by radiocarbon chronologies, lithic artifacts, ceramics, settlement patterns, and ethnobotanical remains from 25 stratified archaeological sites within the Holocene alluvial terrace. The ethnobotanical record consists of 31,500 fragments (13.7 kg) of wood charcoal identified to species and 7.7 kg of carbonized fruits, seeds, nutshells, and cultigens from 956 features. Pollen and plant macrofossils from small ponds both in the uplands and on lower stream terraces record local vegetational changes through the last 1500 to 3000 yr. Human impact increased after cultigens, including squash and gourd, were introduced ca. 4000 yr B.P. during the Archaic cultural period. Forest clearance and cultivation disturbed vegetation on both the floodplain and lower terraces after 2800 yr B.P., during the Woodland period. Permanent Indian settlements and maize and bean agriculture extended to higher terraces 1.5 km from the floodplain by the Mississippian period (1000 to 300 yr B.P.). After 300 yr B.P., extensive land clearance and cultivation by Historic Overhill Cherokee and Euro-Americans spread into the uplands beyond the river valley.     

Age of the five islands formation, Nova Scotia, and the deglaciation of the Bay of Fundy

Three atomic mass spectrometry (AMS) dates have been obtained for shell material from the bottomset beds of a glaciomarine delta at Spencers Island, Nova Scotia, near the head of the Bay of Fundy. The sediments in the delta are part of the previously undated Five Islands Formation, and are the first direct indictaion of the age of deglaciation in this region. The dates range from 14,300 to 12,600 yr B.P. and record the duration of deposition of a diamicton under the deltaic deposits and of the delta itself. The diamicton may have formed around 14,000 yr B.P. under ice-shelf or calving-bay conditions, or by a readvance of grounded ice. The Spencers Island delta is part of a prominent ice-marginal stand marked by numerous deltas along the Minas Basin. The time of formation of the deltas and the inferred ice margin is between 13,500 and 12,000 yr B.P. based on the Spencers Island dates and palynologically confirmed dates on the base of lake-sediment cores from the delta surface. Ice-marginal glaciomarine deposits near St. John, New Brunswick, record a range of radiocarbon dates similar to the Spencers Island dates. This implies that the Bay of Fundy became virtually ice free about 14,000 yr B.P.     

岷江上游河流阶地发育特征及与古滑坡关系初步分析

河流阶地形成演化及其对滑坡的控制是近年来古滑坡研究的热点问题。笔者在对岷江上游河流阶地和古滑坡实地调查测试的基础上,对岷江上游河流阶地的级序、拔河高度、成因类型等进行了分析,绘制了阶地高程位相图和年龄位相图,并结合阶地和古滑坡年代,讨论了阶地与古滑坡的发育关系等。主要取得了以下认识:1)岷江上游的河流阶地具有分段性,成因主要为气候多期次波动与构造活动共同作用,古滑坡及堰塞湖是影响高山峡谷区河流阶地发育的重要因素;2)叠溪-茂县段在20~30 ka B.P.发生了多处大型古滑坡,其中20 ka B.P.的古滑坡可能主要是气候波动引发,30 ka B.P.发生的古滑坡可能主要受控于构造活动(地震);3)岷江上游大量分布的古滑坡堆积体与阶地发育的叠置关系有待进一步理清,开展该地区的河流阶地级序研究要充分考虑古滑坡和堰塞湖的影响.     

Late Quaternary Variations in the Level of Paleo-Lake Malheur, Eastern Oregon

The highest shoreline features of paleo-Lake Malheur are undated gravelly barrier beaches south of Harney Lake that lie ca. 3.5 m higher than the hydrographic outlet of Harney Basin at Malheur Gap (1254 m). The earliest Quaternary record for Lake Malheur consists of occurrences of water-deposited tephra dated to ca. 70,000–80,000 yr ago. The next identified lake interval is dated by shells with ages of ca. 32,000 and 29,500 yr B.P. No dates are available for the terminal-Pleistocene Lake Malheur. Lake(s) were present between ca. 9600 and 7400 yr B.P., although periodic low levels or desiccation are suggested by a paleosol dated as ca. 8000 yr B.P. The lake system probably dried further after 7400 yr B.P., although dates are lacking for the period between ca. 7400 and 5000 yr B.P. Dune deposits on the lake floor are ca. 5000 yr old and indicate generally dry conditions. Fluctuating shallow lakes have probably characterized the last 2000 years. A date of 1000 yr B.P. gives a maximum age for beach deposits at 1254 m, near the basin threshold elevation. Thus, the Malheur Lake system may have drained to the Pacific Ocean by way of Malheur Gap during the latest Holocene.     

Paleoclimatic implications of late quaternary lacustrine sediments in Western Nubia, Sudan

Owing to the hypercontinental location of Western Nubia, secular fluctuations of climate have been filtered and wet phases can be considered as representative of conditions throughout the southeastern Sahara. The study area is crossed by the 20-mm isohyet; between 9300 and about 4000 yr B.P., however, there were widespread lake and swamp environments with freshwater molluscs, ostracods, and diatoms, and a species-rich savanna mammal fauna. The center of the West Nubian Basin (approx. 18°N), an area of about 20,000 km², was occupied by a semiaquatic landscape which was situated at the same latitude as Paleolake Chad. From extensive lake carbonates up to about 4 m thick, a long-term rise of the groudwater table is inferred. Environments developed that now exist at about latitude 13°N. Radiocarbon dates from lake sediment sequences cluster between 30,000 and 21,000 yr B.P., indicating a Pleistocene wet phase. A gap in radiocarbon dates between 21,000 and 11,000 yr B.P. signals a phase of hyperaridity, similar to the present hyperarid phase, with eolian deflation and deposits of sand being the dominant forms of erosion and accumulation.     

Weichselian before 15,000 years B.P. at Jæren-Karmø in southwestern Normay

On the basis of studies of many stratigraphical profiles, together with radiocarbon dates, Thorium-Uranium dates and amino-acid dates, the following preliminary stratigraphy is proposed: (1)Late Weichselian. Stavanger Stadial. The glacier covered the coast and deposited the upper drift sheet. - (2) Middle Weichselian.(a)Sandnes Interstadial (30,000?-39,000 years B.P.). Thick units of marine deposits underlie the Stavanger Stadial drift. The lithology, the foraminiferal fauna, the molluscan fauna and the pollen flora all record cold, partly near-ice environment during their deposition. Elements of a boreal type foraminiferal fauna suggest that certain phases of the Sandnes Interstadial could have been slightly warmer. The shore level was very high. (b) Jæren Stadial (40,000? 1000 years B.P.). Tills and glaciomarine deposits at several locailites are correlated with a Jæren Stadial. (c) Nygaard Interstadial (41,000–50,000? years B.P.). Marine deposits representing a low shore-level phase, record cool to cold conditions. - (3)Early Weichselian. (a) Karmøy Stadial (older than 47,000 years B.P.). Gravelly and very bouldery tills at low stratigraphical levels in several prifles are correlated with a Karmøy Staidial.(b) Older deposits. Marine deposits which lie below the Karmøy Stadial till and on top of Eemian deposits at Bø II on Karmøy are being studies.     

中国内蒙古哈马尔太碱湖Ha01孔岩心13000a以来的古气侯记录

通过对内蒙古哈马尔大碱湖Ｈａ０１孔岩心古气候记录的研究，划分出１３０００ａ以来的１０个气候期及若干气候阶。对比表明，与全球气候变化是一致的。在末次冰期盛冰期之后，冰后期之前，有三次明显的急速降温，先后有老仙女木冰阶、中仙女木冰阶和新仙女木冰阶；冰后期以来，有两次大幅度的降温事件，均具有全球性，一次冷点是７６４０ａＢ．Ｐ，一次冷点为５０００ａＢ．Ｐ，前者相当Ｄｅｍｏｎ称作的第一新冰期，后者相当第一新冰期。近２０００年该盐湖的气候变化与中国历史文献资料相吻合。     

云南北海湿地沉积物记录的过去2050年气候演化及对区域人类文明的影响

过去2 000年气候变化是深入了解过去全球气候演化机制、探索人类活动与环境演化相互关系的重要依据。我国西南地区是气候变化与人类文明研究的重要区域,获取更多记录资料对深入理解两者之间的相互关系尤为重要。本文以云南省腾冲县北海湿地沉积物为研究对象,利用AMS 14C测年建立年代学序列,利用烧失量、粒度分析结果建立了该地区过去2 050年气候演变序列。结果表明:2 050 cal. a B.P.~1 400 cal. a B.P.期间尤其是最后阶段气候寒冷干旱;1 400 cal. a B.P.~750 cal. a B.P.期间相对温暖湿润;750 cal. a B.P.~300 cal. a B.P.期间寒冷干旱;300 cal. a B.P.以来温暖偏湿。通过与云南地区人类活动记录对比发现,该地区人口的增长、社会政权的更替在一定程度上受自然气候环境演化的影响,南诏和大理民族政权的建立主要集中在相对温暖湿润的中世纪暖期;此外,云南地区近2 000年来人口数量的变化与气候变化同样呈现出较好的一致性。     

Radiocarbon dating of subfossil Scots pine (Pinus sylvestris L.) in the southern Swedish Scandes

Wood samples from above the present-day pine limit were collected from within a limited area in central Sweden. New dates from an intensively investigated part of that area all fall within the period 8550 ± 110 to 4270 ± 90 ¹⁴C years B. P. No evidence at present exists to suggest that any drastic change, or fluctuations, in the pine tree-limit, took place within that period. Some dates support the view that the present-day altitude of the pine tree-limit was established during the historic period and perhaps is still declining.