- Reeves, Jessica, Barrows, Timothy, Cohen, Tim, Kiem, Anthony, Bostock, Helen, Fitzsimmons, Kathryn, Jansen, John, Kemp, Justine, Krause, Claire, Petherick, Lynda, Phipps, Steven
- Authors: Reeves, Jessica , Barrows, Timothy , Cohen, Tim , Kiem, Anthony , Bostock, Helen , Fitzsimmons, Kathryn , Jansen, John , Kemp, Justine , Krause, Claire , Petherick, Lynda , Phipps, Steven
- Date: 2013
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 74, no. (2013), p. 21-34
- Full Text: false
- Reviewed:
- Description: The Australian region spans some 60° of latitude and 50° of longitude and displays considerable regional climate variability both today and during the Late Quaternary. A synthesis of marine and terrestrial climate records, combining findings from the Southern Ocean, temperate, tropical and arid zones, identifies a complex response of climate proxies to a background of changing boundary conditions over the last 35,000 years. Climate drivers include the seasonal timing of insolation, greenhouse gas content of the atmosphere, sea level rise and ocean and atmospheric circulation changes. Our compilation finds few climatic events that could be used to construct a climate event stratigraphy for the entire region, limiting the usefulness of this approach. Instead we have taken a spatial approach, looking to discern the patterns of change across the continent.The data identify the clearest and most synchronous climatic response at the time of the Last Glacial Maximum (LGM) (21±3ka), with unambiguous cooling recorded in the ocean, and evidence of glaciation in the highlands of tropical New Guinea, southeast Australia and Tasmania. Many terrestrial records suggest drier conditions, but with the timing of inferred snowmelt, and changes to the rainfall/runoff relationships, driving higher river discharge at the LGM. In contrast, the deglaciation is a time of considerable south-east to north-west variation across the region. Warming was underway in all regions by 17ka. Post-glacial sea level rise and its associated regional impacts have played an important role in determining the magnitude and timing of climate response in the north-west of the continent in contrast to the southern latitudes. No evidence for cooling during the Younger Dryas chronozone is evident in the region, but the Antarctic cold reversal clearly occurs south of Australia. The Holocene period is a time of considerable climate variability associated with an intense monsoon in the tropics early in the Holocene, giving way to a weakened monsoon and an increasingly El Niño-dominated ENSO to the present. The influence of ENSO is evident throughout the southeast of Australia, but not the southwest. This climate history provides a template from which to assess the regionality of climate events across Australia and make comparisons beyond our region. © 2013.
- Description: 4 Earth Sciences
- Description: 21 History And Archaeology
- Petherick, Lynda, Bostock, Helen, Cohen, Tim, Fitzsimmons, Kathryn, Tibby, John, Fletcher, M. S., Moss, Patrick, Reeves, Jessica, Mooney, Scott, Barrows, Timothy, Kemp, Justine, Jansen, John, Nanson, Gerald, Dosseto, Anthony
- Authors: Petherick, Lynda , Bostock, Helen , Cohen, Tim , Fitzsimmons, Kathryn , Tibby, John , Fletcher, M. S. , Moss, Patrick , Reeves, Jessica , Mooney, Scott , Barrows, Timothy , Kemp, Justine , Jansen, John , Nanson, Gerald , Dosseto, Anthony
- Date: 2013
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 74, no. (2013), p. 58-77
- Full Text: false
- Reviewed:
- Description: Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30ka. During the early glacial period (~30-22ka) and the Last Glacial Maximum (~22-18ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important Murray-Darling Basin. The temperate region at this time appears to be dominated by expanded sea ice in the Southern Ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast (including Tasmania) and southwest Australian coasts. The deglacial period (~18-12ka) was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records, while there is some evidence for climatic reversals (e.g. the Antarctic Cold Reversal) in high resolution marine sediment cores through this period. The high spatial density of Holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after ~12ka, presumably in response to increasing temperature, while hydrological records reveal spatially heterogeneous hydro-climatic trends. Patterns after ~6ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the El Niño/Southern Oscillation. © 2013 Elsevier Ltd.
- Description: 2003011211
Palaeoenvironmental change in tropical Australasia over the last 30,000 years - a synthesis by the OZ-INTIMATE group
- Reeves, Jessica, Bostock, Helen, Ayliffe, Linda, Barrows, Timothy, De Deckker, Patrick, Devriendt, Laurent, Dunbar, Gavin, Drysdale, Russell, Fitzsimmons, Kathryn, Gagan, Michael, Griffiths, Michael, Haberle, Simon, Jansen, John, Krause, Claire, Lewis, Stephen, McGregor, Helen, Mooney, Scott, Moss, Patrick, Nanson, Gerald, Purcell, Anthony, van der Kaars, Sander
- Authors: Reeves, Jessica , Bostock, Helen , Ayliffe, Linda , Barrows, Timothy , De Deckker, Patrick , Devriendt, Laurent , Dunbar, Gavin , Drysdale, Russell , Fitzsimmons, Kathryn , Gagan, Michael , Griffiths, Michael , Haberle, Simon , Jansen, John , Krause, Claire , Lewis, Stephen , McGregor, Helen , Mooney, Scott , Moss, Patrick , Nanson, Gerald , Purcell, Anthony , van der Kaars, Sander
- Date: 2013
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 74, no. (2013), p. 97-114
- Full Text:
- Reviewed:
- Description: The tropics are the major source of heat and moisture for the Australasian region. Determining the tropics' response over time to changes in climate forcing mechanisms, such as summer insolation, and the effects of relative sea level on exposed continental shelves during the Last Glacial period, is an ongoing process of re-evaluation. We present a synthesis of climate proxy data from tropical Australasia spanning the last 30,000 years that incorporates deep sea core, coral, speleothem, pollen, charcoal and terrestrial sedimentary records.Today, seasonal variability is governed largely by the annual migration of the inter-tropical convergence zone (ITCZ), influencing this region most strongly during the austral summer. However, the position of the ITCZ has varied through time. Towards the end of Marine Isotope Stage (MIS) 3, conditions were far wetter throughout the region, becoming drier first in the south. Universally cooler land and sea-surface temperature (SST) were characteristic of the Last Glacial Maximum, with drier conditions than previously, although episodic wet periods are noted in the fluvial records of northern Australia. The deglacial period saw warming first in the Coral Sea and then the Indonesian seas, with a pause in this trend around the time of the Antarctic Cold Reversal (c. 14.5ka), coincident with the flooding of the Sunda Shelf. Wetter conditions occurred first in Indonesia around 17ka and northern Australia after 14ka. The early Holocene saw a peak in marine SST to the northwest and northeast of Australia. Modern vegetation was first established on Indonesia, then progressively south and eastward to NE Australia. Flores and the Atherton Tablelands show a dry period around 11.6ka, steadily becoming wetter through the early Holocene. The mid-late Holocene was punctuated by millennial-scale variability, associated with the El Niño-Southern Oscillation; this is evident in the marine, coral, speleothem and pollen records of the region. © 2012.
- Description: 4 Earth Sciences
- Description: 21 History And Archaelogy
- Description: 2003011213
- Authors: Reeves, Jessica , Bostock, Helen , Ayliffe, Linda , Barrows, Timothy , De Deckker, Patrick , Devriendt, Laurent , Dunbar, Gavin , Drysdale, Russell , Fitzsimmons, Kathryn , Gagan, Michael , Griffiths, Michael , Haberle, Simon , Jansen, John , Krause, Claire , Lewis, Stephen , McGregor, Helen , Mooney, Scott , Moss, Patrick , Nanson, Gerald , Purcell, Anthony , van der Kaars, Sander
- Date: 2013
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 74, no. (2013), p. 97-114
- Full Text:
- Reviewed:
- Description: The tropics are the major source of heat and moisture for the Australasian region. Determining the tropics' response over time to changes in climate forcing mechanisms, such as summer insolation, and the effects of relative sea level on exposed continental shelves during the Last Glacial period, is an ongoing process of re-evaluation. We present a synthesis of climate proxy data from tropical Australasia spanning the last 30,000 years that incorporates deep sea core, coral, speleothem, pollen, charcoal and terrestrial sedimentary records.Today, seasonal variability is governed largely by the annual migration of the inter-tropical convergence zone (ITCZ), influencing this region most strongly during the austral summer. However, the position of the ITCZ has varied through time. Towards the end of Marine Isotope Stage (MIS) 3, conditions were far wetter throughout the region, becoming drier first in the south. Universally cooler land and sea-surface temperature (SST) were characteristic of the Last Glacial Maximum, with drier conditions than previously, although episodic wet periods are noted in the fluvial records of northern Australia. The deglacial period saw warming first in the Coral Sea and then the Indonesian seas, with a pause in this trend around the time of the Antarctic Cold Reversal (c. 14.5ka), coincident with the flooding of the Sunda Shelf. Wetter conditions occurred first in Indonesia around 17ka and northern Australia after 14ka. The early Holocene saw a peak in marine SST to the northwest and northeast of Australia. Modern vegetation was first established on Indonesia, then progressively south and eastward to NE Australia. Flores and the Atherton Tablelands show a dry period around 11.6ka, steadily becoming wetter through the early Holocene. The mid-late Holocene was punctuated by millennial-scale variability, associated with the El Niño-Southern Oscillation; this is evident in the marine, coral, speleothem and pollen records of the region. © 2012.
- Description: 4 Earth Sciences
- Description: 21 History And Archaelogy
- Description: 2003011213
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