Vegetation History and Water Fluctuations at Lake Leake, South-Eastern South Australia. II. 50 000 B.P. To 10 000 B.P

1975 ◽  
Vol 23 (5) ◽  
pp. 815 ◽  
Author(s):  
JR Dodson
Keyword(s):  
Vegetation History ◽  
South Australia ◽  
Annual Rainfall ◽  
Drill Core ◽  
Radiocarbon Dates ◽  
Last Glaciation ◽  
Annual Minimum Temperature ◽  
Average Annual Rainfall ◽  
Eucalypt Woodland ◽  
Open Woodland

A drill core from Lake Leake contains a sedimentary sequence extending from about 50,000 B.P. until the present. This paper discusses the results of the pollen analyses and six radiocarbon dates which span the period from about 50,000 until about 10,000 B.P. There are core sections which yielded low numbers of pollen and thus there are gaps in the vegetation record. It is suggested that open eucalypt woodland was replaced by eucalypt woodland with heath at about 50,000 B.P. and remained until about 39,000 B.P. Open woodland then returned but was replaced by eucalypt woodland with heath by 38,000 B.P. Some time after 35,000 B.P., open eucalypt woodland conditions returned and persisted until near 10,000 B.P. when Casuarina stricta migrated into the area. Through- out the period in question the climate was drier than it has been in the last 10,000 radiocarbon years. There were wet periods about 50,000 and 39,000 B.P. and from 38,000 to 35,000 B.P. The character of the sediments and the relative amounts of pollen preserved suggest that conditions were relatively dry from 50,000 to 39,000 B.P. and from after 35,000 until near 10,000 B.P. The lake was driest during the period of the last glaciation but the presence of eucalypt pollen is interpreted as indicating that the average annual minimum temperature was above 10�C and the average annual rainfall was above 20-25 cm.

Grazing management to increase utilisation of phalaris-based pasture in dryland dairy systems

2001 ◽  
Vol 41 (1) ◽  
pp. 29 ◽  
Author(s):  
D. J. Watson ◽  
A. Avery ◽  
G. J. Mitchell ◽  
S. R. Chinner
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
South Australia ◽  
Grazing Management ◽  
Annual Rainfall ◽  
Leaf Stage ◽  
North Eastern ◽  
Average Annual Rainfall ◽  
Metabolisable Energy ◽  
Grazing Strategies

Phalaris (Phalaris aquatica cv. Sirosa)-based pastures at Sandy Creek (north-eastern Victoria) and Flaxley (South Australia) were subjected to grazing strategies based on different pre- and post-grazing pasture dry matter levels for 3 years, 1994–96. At Sandy Creek, 3 treatments consisted of commencing grazing when either 1600 (1), 2200 (2) or 2800 (3) kg dry matter per hectare (DM/ha) of pasture had accumulated, with treatments being grazed to a pasture residual of 1200 kg DM/ha. Grazing strategies were imposed over autumn–winter. At Flaxley, there were 5 treatments. Grazing commenced when either 1800 (1) or 2200 (2) kg DM/ha of pasture had accumulated, and was grazed to a pasture residual of 1200 kg DM/ha. Also when either 2200 (3) or 2600 (4) kg DM/ha of pasture had accumulated and these treatments were grazed to a pasture residual of 1800 kg DM/ha. A further treatment was when phalaris had reached a 4-leaf stage (5) (4 fully expanded leaves per tiller) and this was grazed to a residual of 1200 kg DM/ha. The grazing strategies were imposed over the autumn, winter and spring. Pasture consumption at Sandy Creek was higher in treatments 2 and 3. Pasture metabolisable energy (ME) levels and crude protein contents were not affected by treatment. Pasture consumption at Flaxley was greater in treatments 2 and 4. The strategy of grazing at the phalaris 4-leaf stage (5) showed potential for large spring growth. The ME of pasture was unaffected by treatments. The optimal grazing strategy to increase pasture growth for phalaris cv. Sirosa-based pastures in winter-dominant rainfall zones of temperate Australia, receiving about 700 mm average annual rainfall appears to be: allowing 2200 or 2600 kg DM/ha of pasture to accumulate before grazing back to a pasture residual of 1200 or 1800 kg DM/ha, respectively.

Vegetation history and water fluctuations at Lake Leake, south-eastern South Australia. 1. 10,000 B.P. to present

1974 ◽  
Vol 22 (4) ◽  
pp. 719 ◽  
Author(s):  
JR Dodson
Keyword(s):  
Water Level ◽  
Pollen Analysis ◽  
Vegetation History ◽  
South Australia ◽  
Lake Basin ◽  
Radiocarbon Dates ◽  
South Eastern ◽  
Lower South ◽  
Western Victoria

The stratigraphy and detailed pollen analysis of the top 4 m of sediment in Lake Leake were used to describe the vegetation history and past changes in the water level in the lake basin. Some of the changes described have climatic significance. Six radiocarbon dates are used to place a chronology on these events and the results are used to compare previous work carried out in western Victoria. It is suggested that in south-eastern South Australia, immediately prior to 10,000 B.P., conditions were drier than at present and that after this time conditions became wetter, the wettest period of the last 10,000 years occurring between 6900 and 5000 B.P. After this time conditions became drier, marginally wetter again between 2000 and 1300 B.P., then relatively dry until the present day. Keys to aid in the identification of pollen of the Casuarinaceae, Myriophyllum and the Myrtaceae for species growing in the Lower South-East of South Australia are given.

The numbers and distribution of ammonia-oxidizing bacteria in some Northern Territory and South Australian soils

1960 ◽  
Vol 11 (4) ◽  
pp. 505 ◽  
Author(s):  
CM Sims ◽  
FM Collins
Keyword(s):  
South Australia ◽  
Northern Territory ◽  
Soil Samples ◽  
Nitrifying Bacteria ◽  
Annual Rainfall ◽  
Ammonia Oxidizing Bacteria ◽  
Appreciable Effect ◽  
Liquid Media ◽  
Desert Soils ◽  
Average Annual Rainfall

Ammonia-oxidizing bacteria were detected in 75 soil samples from the Northern Territory and South Australia. Silica gel plates gave soil counts comparable with those obtained in liquid media. The counts varied from 20 to 8000 cells per gram of soil. Nitrosogloea merismoides was detected in 53 of the soils, Nitrosornonas europaea in 39 soils, and Nitrosococcus nitrosus in 14 soils. There was little difference between the numbers and types of nitrifying bacteria present in the desert soils compared with those from the more temperate areas, nor did the average annual rainfall have any appreciable effect.

Past and Present Vegetation of Marshes Swamp in South-Eastern South Australia

1975 ◽  
Vol 23 (1) ◽  
pp. 123 ◽  
Author(s):  
JR Dodson ◽  
IB Wilson
Keyword(s):  
Climatic Change ◽  
Vegetation History ◽  
South Australia ◽  
Plant Succession ◽  
Radiocarbon Dates ◽  
Tea Tree ◽  
South Eastern ◽  
Form Part ◽  
History Of ◽  
Insight Into

The swamp and sclerophyll vegetation of Marshes Swamp is discussed in terms of soils and water regimes. Two swamps, Mt. Burr Swamp and Blue Tea Tree Swamp, which form part of Marshes Swamp, are looked at in particular and their stratigraphy and history are reconstructed. Cores from the swamp were pollen-analysed and the vegetation history of the swamps is described in terms of plant succession and local climatic change. Four radiocarbon dates were obtained and these were used to date the major local vegetational history events following dune build-up and vulcanism. These also allowed some insight into the age of soil development in the swamp.

A Vegetation History of the Far North of New Zealand during the Late Otira (Last) Glaciation

1993 ◽  
Vol 39 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Rewi Newnham ◽  
John Ogden ◽  
Dallas Mildenhall
Keyword(s):  
New Zealand ◽  
Forest Cover ◽  
Vegetation History ◽  
Mixed Forest ◽  
Radiocarbon Dates ◽  
Substantial Loss ◽  
Far North ◽  
Last Glaciation ◽  
Pollen Diagrams ◽  
History Of

AbstractDuring the latter part of the last (Otira) glaciation the forest cover of New Zealand was much reduced. It has frequently been postulated, however, that diverse mixed forest communities survived in the far north of North Island. Pollen diagrams and radiocarbon dates from two last glacial and postglacial (Aranuian) sits on the Aupouri Peninsula in the far north of New Zealand are compared with other published palynological and plant macrofossil evidence from the region. Mixed kauri/podocarp/angiosperm forest was present at times during the late Otiran (and Aranuian) and no evidence was found for substantial loss of forest. However, radiocarbon samples from one site, at least, seem to have been contaminated with young carbon; this introduces uncertainty into the chronology established at that site. Possibly nondeposition or erosion has obscured part or all of the late Otiran record at all the sites studied so that very much reduced forest cover at that time cannot be ruled out.

Late Quaternary Palaeoecology of Wyrie Swamp, Southeastern South Australia

1977 ◽  
Vol 8 (1) ◽  
pp. 97-114 ◽  
Author(s):  
John Dodson
Keyword(s):  
Major Element ◽  
Late Quaternary ◽  
Sand Dunes ◽  
South Australia ◽  
European Settlement ◽  
Last Glaciation ◽  
History Of ◽  
Postglacial Expansion ◽  
Preceding Period ◽  
Open Woodland

Pollen analysis of two radiocarbon-dated cores provides a history of Wyrie Swamp and the surrounding vegetation, and the result compares with other palynological data from southeastern South Australia. Eucalypt (Eucalyptus) forest or woodland with a scrub understory was the major element before about 50,000 years BP, between ca. 40,000 and 30,000 BP, and after ca. 11,000 BP. More open woodland prevailed between ca. 50,000 and 40,000 BP, and between ca. 26,000 and 11,000 BP. Casuarina stricta, common on sand dunes, migrated to the area about 10,500 years ago and remained as a dominant species until the time of European settlement at about 1840 ad . Postglacial expansion of this species implies that the climate since 10,500 years ago has been warmer than in the preceding period. It probably was drier during the period from 50,000 to 10,500 BP than in the Holocene. The driest period was from 26,000 to 11,000 BP, perhaps corresponding to the time of the last glaciation in Australia. The site is archaeologically important, as a number of wood and stone artifacts that date between 10,200 and 8000 BP have been recovered from the swamp sediments.

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

Wind blown sediment mass budget of Sahelian village land units in Niger

2001 ◽  
Vol 172 (5) ◽  
pp. 523-531 ◽  
Author(s):  
Jean-Louis Rajot
Keyword(s):  
Wind Erosion ◽  
Size Range ◽  
Arable Land ◽  
Annual Rainfall ◽  
Complete Disappearance ◽  
Mass Budget ◽  
Sediment Mass ◽  
Aeolian Sediments ◽  
Average Annual Rainfall ◽  
The Village

Abstract To assess the mass budget of aeolian sediments transported by wind (erosion vs. deposition) at the scale of village land units (25 kmX25 km), measurements were carried out during 3 years (from 1996 to 1998) in a cultivated field and in a fallow area simultaneously. These were located in the Sahelian zone of Niger with an average annual rainfall of 560 mm. The vertical upward fluxes of particles <20 mu m exported from the study area were estimated from the horizontal sediment fluxes measured using BSNE sand catchers. This mass of exported dust was compared with the vertical downward fluxes of particles of the same size range (<20 mu m) measured using passive CAPYR collectors. Values of deposition recorded in the field and in the fallow were similar. In the field, wind erosion reached its maximum in May and June when the vegetation cover was minimal. In the fallow area, wind erosion was always very low in comparison with the field. It occurred during the strongest storms when the grass cover was minimal. Nevertheless, the net balance between deposition and erosion was highly positive in the fallow areas. These results have been extrapolated at the scale of the village land units based on the current land use. At this scale, the balance was positive for the arable land, indicating a net deposition of aeolian sediments of +0.36 t ha (super -1) yr (super -1) . However, the complete disappearance of fallow land would result in a balanced budget for the arable land.

scholarly journals Paleoclimatic Implications of Radiocarbon Dating Of Speleothems from the Cracow-Wieluń Upland, Southern Poland

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Anna Pazdur ◽  
Mieczysław F. Pazdur ◽  
Jacek Pawlyta ◽  
Andrzej Górny ◽  
Michał Olszewski
Keyword(s):  
Systematic Study ◽  
Radiocarbon Dating ◽  
Karst Region ◽  
Radiocarbon Dates ◽  
Preliminary Results ◽  
Last Glaciation ◽  
Geological Museum ◽  
Paleoclimatic Records ◽  
Age Range

We report preliminary results of a long-term systematic study intended to gather paleoclimatic records from precisely dated speleothems. The research project is limited to speleothems deposited in caves of the Cracow-Wieluń Upland, the largest and best-explored karst region in Poland, covering ca. 2900 km2 with >1000 caves. Speleothem samples were selected from collections of the Geological Museum of the Academy of Mining and Metallurgy in Cracow. Radiocarbon dates of these samples from ca. 45–20 ka bp almost exactly coincide with age range of the Interplenivistulian. A break in speleothem formation between ca. 20 and 10 ka bp may be interpreted as a result of serious climatic deterioration associated with the maximum extent of the last glaciation. We observed differences among 14C, U/Th and AAR dating results. Changes of δ13C and δ18O in speleothems that grew between ca. 30 and 20 ka bp may be interpreted as changes of paleoclimatic conditions.

The last interglacial–glacial cycle, Clyde foreland, Baffin Island, N.W.T.: stratigraphy, biostratigraphy, and chronology

1977 ◽  
Vol 14 (12) ◽  
pp. 2824-2857 ◽  
Author(s):  
G. H. Miller ◽  
J. T. Andrews ◽  
S. K. Short
Keyword(s):  
Amino Acid ◽  
Marine Sediments ◽  
Baffin Island ◽  
Buried Soils ◽  
Last Interglacial ◽  
Pollen Assemblage ◽  
Outlet Glacier ◽  
Radiocarbon Dates ◽  
Last Glaciation

A study of the stratigraphic sequence (14C and amino acid age control), marine bivalve faunal changes, and palynology of buried soils and organic-rich sediment collected from the Clyde Foreland Formation in the extensive cliff sections of the Clyde foreland, eastern Baffin Island, N.W.T., suggests the following last interglacial – Foxe (last glaciation) glacial – present interglacial sequence.(1) Cape Christian Member (ca. 130 000 years BP?)Consists of the Sledgepointer till overlain by the Cape Christian marine sediments. In situ molluscan fauna, collected from the marine sediments, contain a moderately warm bivalve assemblage. A well-developed soil that formed on the marine sediments (Cape Christian soil) contains an interglacial pollen assemblage dominated by dwarf birch. U-series dates of > 115 000 and ca. 130 000 years BP on molluscs from the Cape Christian marine sediments suggest that they were deposited during the last interglaciation, here termed the Cape Christian Interglaciation. The development of a subarctic pollen assemblage in the Cape Christian soil has not been duplicated during the present interglaciation, suggesting higher summer temperatures and perhaps a duration well in excess of 10 000 years for the last interglaciation.(2) Kuvinilk MemberConsists of fossiliferous marine sediments, locally divided by the Clyde till into upper and lower units. The Clyde till was deposited by the earliest and most extensive advance of the Foxe (last) Glaciation. Kuvinilk marine sediments both under- and overlying the Clyde till contain the pecten Chlamys islandicus, indicating that the outlet glacier advanced into a subarctic marine environment. Amino acid ratios from in situ pelecypod shells abovę and below the Clyde till are not statistically different, but contrast markedly with ratios obtained from the same species in the Cape Christian Member. Organic horizons within the Kuvinilk marine sediments contain a relatively rich pollen assemblage, although 'absolute' counts are low.(3) Kogalu Member (> 35 00014C years BP)Sediments of the Kogalu Member unconformably overlie those of the Kuvinilk Member, but are of a similar character. The dominant sediments are marine in origin, but in places are divided into upper and lower units by the Ayr Lake till. Amino acid ratios from in situ shells above and below the Ayr Lake till are indistinguishable, but substantially less than those in the Kuvinilk Member, suggesting the two members are separated by a considerable time interval. Radiocarbon dates on shells in the Kogalu marine sediments range from 33 000 to 47 700 years BP, but these may be only minimum estimates. The sea transgressed to a maximum level 70–80 m asl, coincident with the glacial maximum. Subarctic marine fauna of interstadial–interglacial character occur within the Kogalu marine sediments.(4) Eglinton Member (10 000 years BP to present)A major unconformity exists between the Kogalu and Eglinton Members. Ravenscraig marine sediments were deposited during an early Holocene marine transgression–regression cycle; the oldest dates on these sediments are ca. 10 000 years BP. Locally a vegetation mat occurs at the base or within the Ravenscraig unit. Pollen from these beds is sparse, but indicates a terrestrial vegetation assemblage as diverse as that of today. There is no evidence that Laurentide Ice reached the foreland during the last 30 000 years. Eolian sands that overlie a soil developed on the marine sediments record a late Holocene climatic deterioration. Pollen in organic-rich sediments at the base of, and within, the eolian sands record a vegetation shift in response to climatic change.

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