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1.
The Blue Mountains region of New South Wales, including the World Heritage listed Blue Mountains National Park, is arguably one of Australia's most highly valued and iconic wilderness areas. Common to this region are upland swamps (formally ‘temperate highland peat swamps on sandstone’), which play a vital hydrological role at the headwaters of the river catchments, as well as providing the habitat for an array of flora and fauna species. This paper involves an interdisciplinary examination into the need and potential for adaptive management in the Blue Mountains. It uses geomorphic (physical) knowledge of swamp condition and social data about the volunteers who rehabilitate them. Research involved using the River Styles river condition framework across 47 swamps and questionnaires and interviews with local rehabilitation volunteers. It is proposed that there is a need and a potential to combine geomorphic understanding with further engagement of community volunteers in order to enable an interdisciplinary approach to adaptive management. Such an approach could result in the effective environmental management of upland swamps in the Blue Mountains.  相似文献   

2.
Deciphering patterns and inferring processes in multicausal floodplain river ecosystems is a challenge in river science. The effects of larger‐scale top‐down constraints and smaller‐scale bottom‐up influences on the spatial patterns of nutrient concentrations across multiple inset‐floodplain surfaces was studied in a large dryland floodplain river (Barwon‐Darling River, south‐east Australia). The distribution of sediment‐associated carbon, nitrogen, and phosphorus was primarily related with significant differences in the textural character of the different floodplain surfaces. Elevation of the different floodplain surfaces above the active channel was a secondary influence on the distribution of carbon and phosphorus. Combined, these factors produce a spatial patch mosaic of sediment associated carbon, nitrogen, and phosphorous across these floodplain surfaces.  相似文献   

3.
The surface of the floodplain of the Ohio River about 20km southwest of Louisville, Kentucky, is a series of linear ridges and swales that are subparallel to the channel of the river, which here is relatively straight and flows southward. Numerous prehistoric occupational sites are located on these ridges. The sediments that underlie the ridges, which were examined in four archaeological excavations as deep as 8 m, are predominantly sandy silt and silty fine to very fine sand and appear to be mainly the product of overbank deposition from suspended load. Abundant cultural material and occupational sites dating as early as 10,000 years BP are found in the sediments at depths as great as 6·5 m. The fine sediments of the floodplain are underlain by sand and gravel.The context of the cultural materials and the stratigraphy and morphology of the deposits indicate that the ridged deposits began as linear riverside sand and gravel bars. These were succeeded upward by fine-grained overbank deposits in which the ridged morphology was maintained because the overbank silt and fine sand were deposited as prograding elongate bars at high water. As the floodplain ridge built upward, the sedimentation rate decreased and the sand content of the sediments diminished, and as the river channel occasionally shifted, the ridged deposits were built in successive subparallel sequences.Two archaeological consequences are implicit in this depositional model of orderly growth of the floodplain. First, available archaeological data from floodplain segments along other parts of the river should confirm the model; and second, the model should make it possible to search the floodplains of the Ohio River for stratified sites of any desired age.  相似文献   

4.
Wetlands are common in Coastal Western Hemlock forests yet the hydrologic processes that generate runoff from small swamps are not completely understood. Direct field observations, hydrologic, and electrical conductivity data were collected from a gently sloping forested swamp complex from July to November 2009. Swamps occupied depressions between raised mounds (0.1 to 3 m high) and were connected by an ephemeral creek. Runoff was controlled by antecedent moisture conditions and influenced by basin microtopography. Two hydrologic regimes occurred during the study period and different runoff processes dominated each regime. Runoff was generated by subsurface flow during dry antecedent conditions as swamps remained hydrologically disconnected from each other. Runoff was generated by surface outflow from hydrologically connected swamps during wet antecedent conditions as ponded water spilled out of the depressions. The forested swamp complex produced a faster but limited hydrologic response during dry antecedent conditions compared to a slower but greater hydrologic response during wet antecedent conditions. Stormwater runoff and runoff ratios were up to two orders of magnitude higher in wet conditions than during similarly sized events in dry conditions. These factors should be considered when designing monitoring programs or runoff models in forested swamps with significant microtopography. Field surveys and estimates of hydrologic inputs and outputs may be useful in predicting the potential hydrologic connectivity of isolated forested swamps.  相似文献   

5.
I would like to point out that the flora of Sumatra is in many respects as spectacular as Rafflesia and the giant Amorphophallus make one suspect (Meijer, unpublished). People should learn to attach the same scientific and aesthetic value to the loss of this flora as to the disappearance of rhinos, tigers, and tapirs. The only fruitful approach to save the tropical rain‐forests of Sumatra is absolute protection of the whole Bukit Barisan Range as a vital water catchment area of this island, to establish buffer zones in the foothills of this reserve, to establish enough reserves in the coastal plain regions and the peat swamps, the mangrove swamps, limestone hills, and Tiga Puluh Mountains to save representative areas. A massive botanical/ecological survey of the whole island is needed for a rational conservation plan. In this, access to centres of higher learning, participation of local universities, and the establishment of a series of local educational and research centres should play a major role. It has been discovered now in Central America (Costa Rice and Panama) that the only feasible way to preserve tropical rain‐forests is through a network of research stations and related scientific tourism.

Also in Sumatra with its local centres of diverse cultures, nature conservation can go hand‐in‐hand with cultural preservation and stimulation of local pride in people's natural heritage.  相似文献   


6.
Palynology, radiocarbon dating, and open-section stratigraphies from archaeological trenches are used to examine the impact of human activity around the time of Norse landnám on vegetation and landscape associated with a small farm (Ø34) in the Qorlortoq valley, Eastern Settlement, Greenland (61° N 45° W). Peat deposits from a mire abutting the Norse ruins revealed a discontinuous palaeoenvironmental record containing a possible hiatus from ca. AD 410–1020. Palaeovegetational data were recovered either side of this period. Pollen assemblages suggest that open Salix scrub dominated the landscape during the pre-settlement phase. The later phases of landnám resulted in the creation of hay fields and heavily-grazed grassy heath. Site abandonment is reflected by a re-expansion of Salix. This occurs shortly before the onset of deposition of a Sphagnum peat, dated to cal AD 1420–1630 (2σ) and reflecting an increase in mire surface wetness, probably in response to a deteriorating climate. Radiocarbon dates were obtained on peat and plant macrofossils sampled from either side of the proposed hiatus at two different but closely-spaced (<20 m) locations across the mire. These produced significantly different dates for the cessation of peat formation in the pre-landnám period (cal BC 2130–1770 and cal AD 240–410 respectively), but near-synchronous dates for the recommencement of peat growth (cal AD 890–1150 for peat and a probably more reliable interval of cal AD 1020–1190 based on plant macrofossils). It is suggested that this hiatus may represent the first direct evidence for peat cutting in Norse Greenland.  相似文献   

7.
A set of 121 radiocarbon and OSL dates has been compiled from the Upper Dnieper River and tributary valleys, Western European Russia. Each date was attributed according to geomorphic/sedimentological events and classes of fluvial activity. Summed probability density functions for each class were used to establish phases of increasing and reducing fluvial activity. The oldest detected reduction of fluvial activity was probably due to glacial damming at LGM. Within the Holocene three palaeohydrological epochs of millennial-scale were found: (1) high activity at 12,000–8,000 cal BP marked by large river palaeochannels; (2) low activity at 8,000–3,000 cal BP marked by formation of zonal-type soils on -floodplains; short episodes of high floods occurred between 6,500—4,400 cal BP; (3) contrasting hydrological oscillations since 3,000 cal BP with periods of high floods between 3,000–2,300 (2,000) and 900–100 cal BP separated by long interval of low floods 2,300 (2,000)-900 cal BP when floodplains were not inundated — zonal-type soils were developing and permanent settlements existed on floodplains. In the last millennium, four centennial-scale intervals were found: high flooding intervals are mid-11–mid-15th century and mid-17–mid-20th century. Intervals of flood activity similar to the present-day were: mid-15–mid-17th century and since mid-19th century till present. In the context of palaeohydrological changes, discussed are selected palaeogeographic issues such as: position of the glacial boundary at LGM, role of changing amounts of river runoff in the Black Sea level changes, floodplain occupation by Early Medieval population.  相似文献   

8.
A distinctive sand layer enclosed within Holocene peat is described from Basta Voe, Isle of Yell, Shetland Isles. The sand layer, that can be traced considerable distances inland and up to a maximum altitude of c. + 9 m OD, is here interpreted as having been deposited by a former tsunami. AMS dating appears to indicate that the tsunami occurred between 1300 – 1570 cal years BP. At present, the tsunami has no known source mechanism although the most likely mechanism is thought to have been an offshore slump or slide. The available information would presently seem to indicate that this tsunami was restricted to the eastern coastline of Shetland. The relatively young age of this inferred tsunami is of considerable importance to planners and engineers concerned with estimating coastal flood frequency and magnitude.  相似文献   

9.
The raised bog sediments that have been continuously accumulated over time represent the most suitable natural object which enables us to reconstruct Late Glacial and Holocene vegetation and palaeoclimates. Bog peat consists of organic carbon formed in situ. It contains moss, plant fragments and microfossils that are necessary for the study of palaeovegetation and palaeoclimate. However, a successful study of palaeoenvironment can be carried out on the basis of investigation of a great quantity of samples along the whole peatbog thickness. In the present paper, the authors present the results of palynological, botanical investigations and radiocarbon dating of 31 peat samples taken from the raised bog Velikoye, located in the eastern part of Kaliningrad Region. The data obtained have enabled us to reconstruct the palaeovegetation, reveal the evolution of the bog and determine rate of peat formation at different evolutional stages over the last 7500 cal BP.  相似文献   

10.
We examine obsidian hydration as a means to date archaeological sites at high elevation in the central Andes, and in particular quarry sites that are difficult to date by radiocarbon means. The Chivay obsidian source lies in a volcanic depression above the Colca Valley in Arequipa, Peru (71.5355° S, 15.6423° E) at 4950 masl. We compare obsidian hydration readings from one quarry and two workshop locations. Ninety-one flakes from the quarry pit, and 61 and 33 flakes from the workshops were analyzed for hydration bands. Of these, 68 from the quarry, and 54 and 33, respectively from the workshops produced at least one culturally meaningful hydration band. As expected, obsidian appears to hydrate slowly at this high elevation. Yet, variation in hydration readings is low within stratigraphic contexts, suggesting relatively narrow windows of knapping activities in each excavation level. A small number of radiocarbon dates allow us to develop a preliminary hydration rate for Chivay obsidian in this high elevation location. Hydration data indicate that intensive quarrying began by 3800 cal. BC and stopped ca. 2300 cal. BC. By contrast, the two workshops appear to have been deposited 2900 and 1200 cal. BC, and 2700 and 2400 cal. BC. The data are consistent with an uptick in obsidian use by at least the Terminal Archaic period.  相似文献   

11.
Following the exceptional discovery of Neolithic engravings on a boulder at Vallée aux Noirs in the Fontainebleau forest, south of Paris, an excavation trench was opened in order to access the buried part of the decorated rock panel and explore the stratigraphic context of the artwork. A palaeosol was found two metres below the modern ground level, underneath multiple layers of sterile sandy soil forming a very compact sequence from which only one archaeological artefact was recovered – an Iron Age fibula (c.200–300 BC). Dating of the palaeosol was attempted through two different methods: AMS dates from charcoal suggest a significant span from the Early Bronze Age to the Iron Age, while two more consistent OSL dates point to formation of the palaeosol during the Late Neolithic (3500–3000 cal BC). The entire engraved rock surface (16 m2), including its buried part, was fully recorded. Four main semiotic groups were identified: a typical fifth‐millennium crook‐hafted axe with a ring, two boats with steering oars, and a central, very tall human figure dominating the composition from its 3.5‐metre height.  相似文献   

12.
Excavations at the archaeological site of Encosta de Sant'Ana (Lisbon, Portugal) uncovered a mid-Holocene buried alluvial soil associated with early Neolithic occupation layers. Routine laboratory analyses and micromorphological observations were undertaken on the soil material. Humic acids from its Ab horizon, as well as Neolithic ecofacts, were radiocarbon dated. The dates obtained indicate that soil was formed between c. 8.0 and 6.0 cal ka BP and that the pedological evidence fits the record of the North Atlantic Holocene IRD events (“Bond events”) and the so-called “Holocene climate optimum”. The geoarchaeological record reveals that Neolithic inhabitants settled upon a stable surface, still affected by soil formation that was suddenly interrupted by slope wasting, probably in correspondence to Bond event 4, at c. 6.0 cal ka BP.  相似文献   

13.
The drainage of Lake Hula and its swamps in the 1950s created a new landform and changed the hydrological and sedimentological regime in the Hula valley. The affected area extended over 40 km2 and the work basically improved the drainage conditions of another 20 km2 that were periodically affected by flooding. This man‐made project marked the termination of one of the oldest documented lakes and surrounding wetlands in history, with a rich and diverse aquatic biota. The reclaimed swampy land started to settle immediately upon drainage, mainly due to the compaction of the peat layers. The mean yearly settling rate was 8 cm yr–1. Agricultural development of the reclaimed land was unsuccessful, and soils were affected by continuous underground fires. Weathered peat soils, without a vegetation cover, were eroded by wind. Another ecological effect was the release of nutrients by the decomposing peat, with the nutrients carried by the Jordan river floods into the eutrophic Lake Kinneret. To prevent the natural subsidence a small shallow lake, 110 ha in area, and a network of canals were created in the 1990s. This new wetland and the adjacent agricultural areas are the targets of a multidisciplinary monitoring program. An eco‐tourism development project is currently being planned. Almost 50 years after starting the drainage project the present trend is to restore at least a small fragment of the previous landscape and ecosystem.  相似文献   

14.
Although concave-bank benches rarely occur in freely meandering rivers, they may constitute a significant proportion of the floodplain formed by the downvalley migration of the tight channel bends of confined meanders. This study reports the results of a field survey of the floodplains of Fort Nelson and Muskwa rivers, two of many northeastern British Columbian rivers whose meandering is confined between the resistant valley sides of former glacial meltwater channels. The formation and character of contemporary concave-bank benches and the morphology and sediments of the corresponding floodplain features are described. The concave-bank benches form lateral ribbons of deposition along the valley walls and constitute about one-third of the entire floodplain.  相似文献   

15.
The paper applies Bayesian statistical modelling to radiocarbon dates obtained for a stratigraphic sequence comprising occupation features and superimposed burials from the Late Mesolithic (c.7400–6200 cal BC) to the Mesolithic–Neolithic transition (c.6200–5900 cal BC), from Vlasac in the Danube Gorges region of the north‐central Balkans. This sequence, investigated in the course of excavations at the site in 2006–9, yielded stratigraphic evidence of the transformation of local forager populations as a result of contact with Neolithic communities. Our paper provides a reliable chronological framework for changes from Late Mesolithic burial rites to new, Neolithic types of ornamental beads at the top of the sequence. The use of the same burial location and continuities in burial rites over a considerable period of time raise significant questions about the role of tradition and the potential for enduring practices in prehistoric societies.  相似文献   

16.
The earliest evidence of prehistoric religious practice in China found so far comes from excavations at Beifudi, about 120 km south of Beijing, in the form of votive offerings and porcelain sorcery masks dated to the period 8000–7000 yr BP. These finds are part of a rich Neolithic site located on the second river terrace on the north shore of the Yi River. This paper presents results of pollen analysis of part of a sediment profile from a depression at the edge of first terrace towards second terrace, a few hundred metres away from the main archaeological finds. A sequence of marked changes in environment occurred between 9000 cal yr BP and 6000 cal yr BP, and dating evidence suggests strong associations with the ebb and flow of human activity in the area. The first phase of activity on the site begins at around 8000 cal yr BP, towards the end of a period of relatively dry, cold environmental conditions. Between 7800 cal yr BP and 7400 cal yr BP, the first clear evidence of cereal cultivation appears in the pollen record. Rich archaeological finds occur during the same time period, suggesting local prosperity. This first phase of the Beifudi culture ends at 7300 cal yr BP, when warmer and wetter conditions are inferred and wetland areas expand, reducing the area available for crop cultivation near the site. A return to drier and cooler conditions from 6900 cal yr BP corresponds with the second phase of apparent prosperity in the archaeological record from Beifudi. This phase ends at around 6500 cal yr BP, at the start of another shift towards wetter conditions in the flood plain environment. The pollen record suggests that environmental conditions in the flood plain were a major determinant of human activity at Beifudi in the early-mid Holocene.  相似文献   

17.
Abstract

Multi-proxy analyses from floodplain deposits in the Colne Valley, southern England, have provided a palaeoenvironmental context for the immediately adjacent Terminal Upper Palaeolithic and Early Mesolithic site of Three Ways Wharf. These deposits show the transition from an open cool environment to fully developed heterogeneous floodplain vegetation during the Early Mesolithic. Several distinct phases of burning are shown to have occurred that are chronologically contemporary with the local archaeological record. The floodplain itself is shown to have supported a number of rare Urwaldrelikt insect species implying human manipulation of the floodplain at this time must have been limited or episodic. By the Late Mesolithic a reed-sedge swamp had developed across much of the floodplain, within which repeated burning of the in situ vegetation took place. This indicates deliberate land management practices utilising fire, comparable with findings from other floodplain sequences in southern Britain. With similar sedimentary sequences known to exist across the Colne Valley, often closely associated with contemporary archaeology, the potential for placing the archaeological record within a spatially explicit palaeoenvironmental context is great.  相似文献   

18.
The 137Cs (caesium‐137) method was used to investigate medium‐term rates of sediment deposition on the floodplain of the Labasa River, on Vanua Levu island in northern Fiji. The Labasa basin is commercially important for sugarcane farming, which provides much revenue and sustains the economy in the greater Labasa area. Alluvium was sampled at three riverbank sites in vertical increments of 30 mm. Measured net vertical accretion rates, based on analysis of depth‐profiles of 137Cs activity, ranged from 10 mm yr?1 at a low‐lying site near a tributary confluence with the main river, to 60 mm yr?1 on a levée that was elevated slightly above the adjacent floodplain. These rates of accretion are high, but in general agreement with rates recorded using similar methods in other tropical Pacific island river systems. Soil erosion under sugarcane on hilly parts of the lower Labasa basin is an important factor in rapid floodplain development. Observations made during Cyclone Ami, which traversed Vanua Levu island in early 2003, illustrate the major contribution of severe storm events to floodplain sediment supply, by triggering numerous landslides on catchment slopes and in‐channel debris floods, and by generating large‐magnitude overbank floods.  相似文献   

19.
Two spring-fed swamp deposits in northwestern Tasmania which contain non-marine ostracods are characterized by an alternation of marl, peaty marl and peaty layers: the Pulbeena Swamp deposit (4.80 m thick) was formed over approximately the last 80,000 years, and Mowbray Swamp (2 m thick) over about the last 110,000 years. Fifteen ostracod species have been recovered from 179 samples: three are new, three are in open nomenclature and the others have living representatives.

The ostracod data compared with pollen curves for both sites demonstrate, for most levels, a good correlation between the abundance of ostracods and that of Cyperaceae and Potamogeton-Triglochin pollen. This implies that ostracods can be successfully used as indicators of different water regimes for spring-fed swamps. Comparison of the ostracod fauna from the two Tasmanian sites is also made with that of other known Australian and New Zealand swamp deposits.  相似文献   

20.
位于湖南道县的玉蟾岩遗址包含大量灰烬,丰富的动物遗存,砾石和石片石器以及骨角器。从出土遗物,特别是人工制品来看,该洞穴应是一处旧石器晚期狩猎采集者的营地。洞穴堆积反映出人类的一系列短期活动或栖居,其间穿插着遗址被废弃的时期。微形态学研究显示堆积中的红色粘土条带是当时人类从洞外搬进来的。该遗址还出土了若干陶片,可以复原成2件或更多的陶器。多数陶片出自于1993和1995年的发掘。另有10多件陶片在2004和2005年的发掘中被发现。我们将在本文介绍该洞穴堆积的年代研究过程和结果,包括样品的采集、预筛选和前处理过程,以及最后对保存好的炭屑和骨头样品的测年。玉蟾岩遗址的年代为距今21000~13800年(校正后,后同),年代数据表明下层堆积中存在人类栖居的间断,陶片的年代为距今17,000~18,000年。这些陶片是在中国发现的制造陶器的最早证据之一。  相似文献   

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