Stratigraphy, Pollen Analysis, and Paleoclimatic Interpretation of Pulbeena Swamp, Northwestern Tasmania

1982 ◽  
Vol 18 (1) ◽  
pp. 108-126 ◽  
Author(s):  
E. A. Colhoun ◽  
G. van de Geer ◽  
W. G. Mook
Keyword(s):  
Pollen Analysis ◽  
Climatic Conditions ◽  
Major Phase ◽  
The Holocene ◽  
Last Glacial ◽  
Pollen Zone ◽  
Peat Deposits ◽  
Glacial Stage ◽  
The Last Glacial

AbstractSedimentary, palynologic, and 14C analysis of 480 cm of freshwater marl and swamp-peat deposits, formed under the influence of fluctuating artesian springs, provides a paleoenvironmental and paleoclimatic record of approximately 65,000 yr for northwestern Tasmania.The Holocene (Pollen Zone 1, 11,000-0 yr B.P.) climate was warm and moist, and forest vegetation was dominant throughout the area. During the later part of the last glacial stage (Pollen Zone 2, 35,000–11,000 yr B.P.) the climate was generally drier, and grassy open environments were widespread. The driest part of this period occurred between 25,000 to 11,000 yr B.P., when temperatures in western Tasmania were markedly reduced during the last major phase of glaciation. Prior to 35,000 yr B.P. (Pollen Zones 3–9) a long “interstadial complex” dating to the middle of the last glacial stage is recognized. During this period the climate was generally moist, and forest and scrub communities were more important than during the later part of the last glacial stage, except during Pollen Zone 5 when high Gramineae plus Compositae values suggest drier conditions. High Gramineae and Compositae values also occur in Pollen Zone 10 at the base of the diagram. They suggest that a phase of drier and cooler climatic conditions occurred during the early part of the last glacial stage.

Late Quaternary environment of southern Windmill Islands, East Antarctica

2002 ◽  
Vol 14 (4) ◽  
pp. 385-394 ◽  
Author(s):  
HELEN KIRKUP ◽  
MARTIN MELLES ◽  
DAMIAN B. GORE
Keyword(s):  
Late Quaternary ◽  
Ice Core ◽  
Open Water ◽  
Climatic Conditions ◽  
East Antarctica ◽  
The Holocene ◽  
Last Glacial ◽  
The Core ◽  
Windmill Islands ◽  
The Last Glacial

Analyses on a sediment core collected from the Windmill Islands, East Antarctica are used to demonstrate that climatic conditions in this region prior to the Last Glacial Maximum were similar to those during the Holocene and that the area was overrun by ice at some stage between 26 kyr BP and the onset of biogenic sedimentation 11 kyr BP. The 10.9 m long core was taken from a marine inlet (epishelf lake) on Peterson Island and is predominantly a sapropel of Holocene age. Material in the lower part of the core includes a till layer lain down during the last glacial in the region and below this till is material which has been dated to 26 kyr BP. Geochemical analyses conducted on the core demonstrate similarities between the Holocene sequence and the preglacial material. The Holocene sequence shows enhanced biogenic production and periods of open water around 4 kyr BP, suggesting a climatic optimum around that time. A subsequent decline in conditions, probably a colder climate with greater extent of sea ice, is evident from 1 kyr BP to the present. The data support results from ice core studies on nearby Law Dome, which suggest there was a period of warming around 11.5 to 9 kyr BP, that recent summer temperatures are low relative to a few centuries ago, and that increasing winter temperatures are the main contributing factor to a recent overall warming in the region.

Introduction

1998 ◽  
Vol 10 (3) ◽  
pp. 225-226
Author(s):  
Ian D. Goodwin ◽  
Carol J. Pudsey
Keyword(s):  
Regional Differences ◽  
Late Quaternary ◽  
Ice Sheet ◽  
List Type ◽  
Glacial Cycle ◽  
The Holocene ◽  
Last Glacial ◽  
Glacial Stage ◽  
The Antarctic ◽  
The Last Glacial

This issue contains a group of papers selected from those presented at the 1st workshop of the SCAR-GLOCHANT and IGBP-PAGES cosponsored programme on the Late Quaternary Sedimentary Record of the Antarctic Ice Margin Evolution (ANTIME), held in Hobart, 6-1 1 July 1997. ANTIME is focused on the circurn Antarctic reconstruction of palaeoclimate, palaeoenvironment, and ice sheet palaeogeography throughout the last glacial cycle. There were 65 participants from Australia, USA, UK, Italy, Spain, Japan, Sweden, Germany and Russia at the workshop. The participants included representatives of PAGES, IMAGES, and INQUA. The workshop included three scientific sessions on: Extent, timing and regional differences during Glacial Stage 2 (10–30 kyr BP) in Antarctica, from the terrestrial and marine records;Climatic, environmental and glacial events during the Holocene;Late Quaternary geochronological problems in Antarctica.

The onset of deglaciation of Cumberland Bay and Stromness Bay, South Georgia

2005 ◽  
Vol 17 (1) ◽  
pp. 29-32 ◽  
Author(s):  
N. VAN DER PUTTEN ◽  
C. VERBRUGGEN
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Aquatic Habitats ◽  
The Holocene ◽  
Carbon Dating ◽  
South Georgia ◽  
Last Glacial ◽  
Peat Deposits ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Carbon dating of basal peat deposits in Cumberland Bay and Stromness Bay and sediments from a lake in Stromness Bay, South Georgia indicates deglaciation at the very beginning of the Holocene before c. 9500 14C yr BP. This post-dates the deglaciation of one local lake which has been ice-free since at least 15 700 14C yr BP on account of its atypical geomorphological location. The latter indicates the likely presence of floristic refugia on South Georgia during the Last Glacial Maximum from which newly exposed terrestrial and aquatic habitats were rapidly colonized.

A multidisciplinary approach to reveal the Sicily Climate and Environment over the last 20 000 years

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Alessandro Incarbona ◽  
Giuseppe Zarcone ◽  
Mauro Agate ◽  
Sergio Bonomo ◽  
Enrico Stefano ◽  
...  
Keyword(s):  
Vegetation Pattern ◽  
Significant Loss ◽  
Climatic Conditions ◽  
Ice Age ◽  
Geochemical Data ◽  
Climatic Fluctuations ◽  
The Holocene ◽  
Last Glacial ◽  
General Decline ◽  
The Last Glacial

AbstractWe present a thorough review of the knowledge on the climate and environment in Sicily over the last 20 000 years, taking into account results of several studies carried using terrestrial and marine records. We obtain a coherent framework of the most important changes succeeded in the island, even if some points need further investigation.All the reconstructions of surface temperatures of the seas and the air surrounding Sicily point out severe climatic conditions during the last glacial period. The steppe- and semisteppe-like vegetation pattern testifies, together with additional evidence from geochemical data of lacustrine evidence, markedly arid conditions. Fi-nally, significant episodes of sea level drop connected Sicily to the Italian Peninsula and favoured the dispersion of faunal elements from southern Italy.The transition between the last glacial and the Holocene was not characterized by a gradual warming but was punctuated by two abrupt suborbital climatic fluctuations: Bølling-Allerød (warm) and Younger Dryas (cold), as recognized in the sediments recovered close to the northern and southern coast of Sicily. A denser arboreal cover is possibly indicated by the occurrence of dormouse and Arvicola remains.Finally the sensitivity of Sicily to climate perturbations is demonstrated by the occurrence of repeated subtle climatic anomalies during the Holocene, including the Little Ice Age, also known from historical chronicles. Forests, woods and Mediterranean maquis developed in the early-middle Holocene. Thereafter was a general decline of arboreal vegetation, following a general aridification trend that seems to be a common feature in southern Europe and North Africa. Science Greek colonization (7th century before Christ), the landscape was intensively modelled for agriculture and breeding, leading to a significant loss of vegetation cover.

Radiocarbon Evidence for Rates of Lateral Expansion in Raised Mires in Southern Finland

1994 ◽  
Vol 42 (3) ◽  
pp. 299-307 ◽  
Author(s):  
Atte A. Korhola
Keyword(s):  
Environmental Control ◽  
Climatic Conditions ◽  
Rapid Expansion ◽  
Lateral Extension ◽  
Lateral Expansion ◽  
Morphometric Measurements ◽  
The Holocene ◽  
Peat Deposits ◽  
Marginal Areas ◽  
Horizontal Expansion

AbstractRadiocarbon ages from the bottom peat deposits and detailed morphometric measurements at five peatlands in the boreal region of southern Finland were used to reconstruct the Holocene patterns of raised mire development. The results suggest that the areal expansion of the mires has been extremely rapid at times—up to several hundreds hectares per millennium—but the periods of more rapid expansion were not coincident among the mires. The rate of lateral extension was shown to depend mainly on the topography of the mineral substrate. Horizontal expansion did not always correlate with vertical growth. Mires expanded slowly between ca. 6000 and 4000 yr B.P., probably as a consequence of drier climatic conditions at that time. The mires also expanded slowly during the two to three recent millennia, the reason for this most probably lying in steepening of the bottom gradient toward the marginal areas of the present mires, The results point to a substantial measure of local environmental control over the lateral extension in raised mire ecosystems.

LONG-TERM RATES OF FAULTING DERIVED FROM COSMOGENIC NUCLIDES AND SHORT-TERM VARIATIONS CAUSED BY GLACIAL-INTERGLACIAL VOLUME CHANGES OF GLACIERS AND LAKES

2006 ◽  
Vol 20 (03) ◽  
pp. 261-276 ◽  
Author(s):  
RALF HETZEL ◽  
ANDREA HAMPEL
Keyword(s):  
Slip Rate ◽  
Alluvial Fan ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Slip Rates ◽  
The Holocene ◽  
Last Glacial ◽  
River Terraces ◽  
The Last Glacial

Seismic hazard evaluations on major faults in Earth's crust are based on their slip histories, which reflect the frequency of earthquakes that ruptured a fault in the past. On a 100 000-year timescale, the slip rate of a fault can be determined by dating geomorphic surfaces that are offset by a fault. Application of this method to alluvial fan surfaces and river terraces offset by thrust faults in Tibet yields long-term slip rates of less than 1mm/a. Slip rates on a 10 000-year timescale are derived from paleoseismologic data and document that faults experience considerable slip rate variations on timescales of 100 to 1000 years. In particular, slip rates are often considerable higher in the present interglacial, the Holocene, than during the last glacial period, the Late Pleistocene. The causes of this behavior have remained enigmatic but their assessment is essential for an accurate evaluation of a fault's past and future seismicity. Numerical experiments show that the retreat of lakes and glaciers at the end of the last glacial period can cause an increase in the Holocene slip rate of a fault. Such a correlation between enhanced seismicity and climate-driven mass fluctuations on Earth's surface is best documented for the Wasatch Fault, Utah.

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