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1.
Geomorphology, geochronology and palynology are used to assess the development and stability of two channelled swamps on the Barrington Tops plateau. While both swamps commenced peat accumulation prior to about 4000 cal BP, new stratigraphic data indicate incision between 700 and 1000 cal BP, in response to regional climate change. Two broad stratigraphic units are identified in each swamp: the upper floodplain, comprised entirely of peat, and the inset floodplain, underlain by interbedded peat and fluvial sediments. Following incision, rapid vertical growth of the inset floodplain occurred on the Barrington River between 690 and 620 cal BP, and palynological data indicate a change from more saturated pre‐incision swamp flora to less saturated post‐incision swamp flora. Bankfull stage‐height, achieved many times in a year, is remarkably consistent along the length of each swamp channel. Its elevation controls the overall elevation of the swamps by controlling the height of the water‐table and hence the growth of swamp vegetation and formation of peat. In particular, contemporary channel dimensions control the growth and height of the inset floodplain, a process that results in the formation of an organic floodplain not previously described in the geomorphic literature.  相似文献   

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Abstract

Surface visibility is a significant constraint in archaeological survey, and estimates of surface visibility are a common addition to cultural resource management reports. Despite this, relatively few studies have attempted to identify the factors affecting visibility and quantify their effects. We report the results of such a study based on analysis of surface stone artifacts deposited by prehistoric hunter-gatherers from the Stud Creek area in what is now Sturt National Park, western New South Wales, Australia. While we are able to demonstrate and quantify relationships between high artifact visibility and erosional surfaces, and low visibility and vegetated or depositional surfaces, our findings also indicate a high degree of local variability. This variability sometimes obscures the predicted relationships. The outcome of this research leads us to question the way some sampling designs for archaeological survey are constructed.  相似文献   

3.
Transverse sections of Chirodipterus australis and Griphognathus whitei are used to demonstrate the histological structures of the rostral and symphysial tubuli in Devonian lungfish. The walls of the tubuli are composed of bony tissue indistinguishable from the cancellar bone found in dermal bone. It has many spaces and perforations, and is contiguous in places with the cancellar bone of the external dermal bone. The walls of lateral-line canals have the same histological structure as the walls of the tubuli; they also intercommunicate with them. The tubuli and the lateral-line canals open to the surface through large perforations on the external surface. In Griphognathus the walls of the tubes under the external dermal bone have two layers: the outer one is dense bone, but the inner one has the appearance of calcified fibrous connective tissue of the kind associated with the tissue surrounding the lateral-line canals in living lungfish. The tubuli are closely related to the pore-canal system via canals that penetrate the dermal bone; this same relationship has been observed in Dipnorhynchus and Speonesydrion. The intimate connection between the tubuli and the lateral-line system suggests that they were formed by the sinking of neuromasts into and under the external dermal bone, with their walls surrounded by cancellar bone.  相似文献   

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Lateritic profiles near Jervis Bay developed under humid temperate climates on a surface of considerable relief. δ18O and TL dating of these profiles indicates that their ages range from Late Mesozoic-Early Tertiary to Late Pleistocene. These profiles thus demonstrate a complexity of development far greater than that allowed for in traditional explanations which attributed lateritic weathering to the effects of tropical climates on Middle Tertiary erosional surfaces.  相似文献   

6.
Bell, P.R., Burns, M.E. & Smith, E.T. October 2017. A probable ankylosaurian (Dinosauria, Thyreophora) from the Early Cretaceous of New South Wales, Australia. Alcheringa 42, 120–124. ISSN 0311-5518.

We describe an isolated osteoderm from the Albian Griman Creek Formation where it is exposed near the town of Lightning Ridge in central-northern New South Wales, Australia. Several lines of evidence allow referral of this element to the Ankylosauria—a group that epitomises body armour and ubiquitous osteodermal coverage among dinosaurs. Despite the abundant record of fossil vertebrates from this interval, ankylosaurians have not been previously reported, although, they have been described from penecontemporaneous deposits in western Queensland and Victoria. This discovery, therefore, provides an important link between the northerly faunas (including the Griman Creek Formation) that flourished at the edge of the epeiric Eromanga Sea, with those from the sub-polar rift-valley system of Victoria during the mid-Cretaceous.

Phil R. Bell [], School of Environmental and Rural Science, University of New England, Armidale 2351, NSW, Australia; Michael E. Burns [], Department of Biology, Jacksonville State University, 700 Pelham Rd N., Jacksonville, AL 36265-2138, USA; Elizabeth T. Smith [], Australian Opal Centre, Lightning Ridge 2834, NSW, Australia.  相似文献   


7.
Unconsolidated sediments from a borehole in Botany Bay have been analyzed for their foraminiferal content. Faunas from between 41 and 54 m below sea level are interpreted as Pleistocene in age. The foraminiferal assemblage from 54 m indicates marine conditions of moderately deep water (25–30 m), and a climate warmer than at present. The higher assemblages indicate a more brackish environment

The foraminifera, belonging to 123 species in 67 genera, are tabulated and 24 are discussed and illustrated. Three species, Oolina bifidocostata, Fissurina alatoquadrata and Elphidium botaniensis and one subpecies, Quinqueloculina affinis atrata, are described as new.  相似文献   

8.
A trilobite fauna from the upper part of the Cotton Formation (late Llandovery, Spirograptus turriculatus Zone) in central west New South Wales includes the new species Raphiophorus sandfordi, Odontopleura (Sinespinaspis) markhami and Aulacopleura pogsoni. Species of Odontopleura and Aulacopleura have not previously been documented in Australasia. The association of these genera is observed in offshore biofacies in the Llandovery/Wenlock on several palaeocontinents. Affinities of the species are with congeners from Bohemia and northwestern Canada (Odontopleura, Aulacopleura) and Tarim and South China (Aulacopleura, Raphiophorus).  相似文献   

9.
In this article, ‘Development’ and developmentist ideas, two increasingly fashionable areas of historical inquiry, are explored in the context of relations between the United States and Brazil through the middle decades of the twentieth century, with three arguments made along the way. First, and in contrast to much academic and extra-academic received wisdom (as well as the official pronouncements of US diplomats), the United States government offered no singular or consistent approach to ‘development’ in its dealings with Brazil. Second, an unofficial vision of development (here termed ‘market developmentalism’) that has so far eluded the attention of historians of developmentalist ideas emerged earlier than the official developmentalisms that have been the main object of historiographic interest to date. Third, this unofficial, largely private, consumption-oriented developmentalism is shown to have enjoyed an outsized influence in Brazil, dwarfing the influence enjoyed by those inconsistent varieties of developmentalism espoused by US diplomats between the 1940s and the 1960s.  相似文献   

10.
Many empirically derived models of downstream changes in channel form are based on the concept of hydraulic geometry, whereby changes in channel morphological variables are related by a continuous power function to increasing discharge or its surrogate. However, changes in discharge throughout a drainage basin are normally concentrated at the junctions of stream channels. At junctions, the relationship between discharge and channel morphology is discontinuous. Some Lower Hunter Valley stream channels were surveyed upstream and downstream of tributary junctions. While significant regional downstream relationships were established, consistent trends at tributary junctions were not apparent from the data. It is possible that considerable scatter evident in ratios of change on either side of each junction was due to local within-site variability. In addition, the relative timing of discharge inputs and the nature of introduced sediment loads could be important in determining the magnitude and direction of channel change at tributary junctions. Interrelated changes in cross-sectional, profile and planform variables may be expected below junctions. The resultant channel morphology, in terms of these variables, might not be wholly determinate.  相似文献   

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Palaeolimnadiopsis bassi sp. nov. is described from the mid-Triassic Hawkesbury Sandstone of the Sydney Basin, New South Wales. It is distinguished from other species of the genus by its paired growth lines, moderately large size, nonterminal umbo, and small larval valve. Macrolimnadiopsis, Pteriograpta, and Limnadia (Falsisca) are considered to be synonymous with Palaeolimnadiopsis, and Belgolimnadiopsis with Euestheria.  相似文献   

13.
Over recent years, roadside memorials to commemorate people killed in motor vehicle accidents have become increasingly noticeable in parts of the Australian landscape. In Newcastle, New South Wales, roadside memorials are placed for young people. The age/gender group most at risk of road death, and those most memorialised, are young men. This is linked to spatially specific constructions of masculinity which circulate within youth milieux of Newcastle. Like other memorials and monuments these ‘deathscapes’ have multiple meanings, differing between those who build, maintain and interpret them. They function as conservative memorials of youth machismo; of heroic aggression, disregard for safety and egocentrism. Roadside memorials need to be re-read as symbolic of societal flaws; of a wasteful road toll, and a testament to dominant and problematic strains of masculinity.  相似文献   

14.
Fossil ostracods from the uppermost 3m of core LG4 from Lake George all have modern living representatives. This part of the core is thought to represent deposition during the last 60,000 years (see Singh et al., 1981b) and the lake hisotry is traced from a knowledge of the ostracod ecology.

The following distinct phases, and their respective timing, are postulated for Lake George (the timing of events should be considered with caution as few 14C dates are available): water fresh and lake full for the periods of 10,200 – 12,000 yBP and 19,100 – 20,700 yBP, water fresh, ephemeral at times, for the periods of 3,200–4,000 yBP, 7,000 yBP, 7,500 yBP, 8,500–10,200 yBP, 12,000–13,500 yBP, 20,700–23,500 yBP, 23,800–27,600 yBP and at some stage between 27,000 and 60,000 yBP; ephemeral saline water for a few short episodes between 3,200 and 4,000 yBP and for the periods of 15,600–17,400 yBP and 23,800–27,600 yBP; lake definitely dry between 17,400 and 19,100 yBP.

Data obtained from the ostracods correlate reasonably well with those of lake level fluctuations based on the study of ancient shorelines by Coventry (1976) and others based on facies analyses and the record of plant microfossils by Singh et al. (1981b).  相似文献   

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Fragments of plastron and vertebrae from the Griman Creek Formation (middle Albian) at Lightning Ridge, New South Wales, extend the Australian record for chelid pleurodires back in time by over 50 my. Contemporaneous with the oldest known occurrences of chelids in Patagonia, this record indicates that during globally warm intervals, pleurodire distribution included high palaeolatitude locations. Although referred to Chelidae, the material shows no characters to enable more detailed taxonomic assessment and it is unclear whether known genera are represented. The diverse and prolonged history of chelids in South America and Australia indicates that the basal eupleurodiran divergence occurred deep in the Jurassic.  相似文献   

17.
Dentigerous jawbones of ischnacanthid acanthodians from the Lower Devonian Currajong Limestone Member and the lower part of the Bloomfield Limestone Member of the Taemas Limestone (Murrumbidgee Group: early Emsian) in the Murrumbidgee valley at Good Hope, Taemas district, and the Goodradigbee valley at Wee Jasper are described. Three taxa of Taemasacanthus are recognized: T. sp. cf. erroli Long, 1986; T. narrengullenensis sp. nov. and T. cooradigbeensis sp. nov. Fragmentary fin spine remains and scales are also described.  相似文献   

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