نتایج جستجو برای: holocene

تعداد نتایج: 8437  

2017
Andrew Bevan Sue Colledge Dorian Fuller Ralph Fyfe Stephen Shennan Chris Stevens

We consider the long-term relationship between human demography, food production, and Holocene climate via an archaeological radiocarbon date series of unprecedented sampling density and detail. There is striking consistency in the inferred human population dynamics across different regions of Britain and Ireland during the middle and later Holocene. Major cross-regional population downturns in...

2012
J. E. Tierney D. W. Oppo A. N. LeGrande Y. Huang Y. Rosenthal B. K. Linsley

[1] Existing paleoclimate data suggest a complex evolution of hydroclimate within the Indo-Pacific Warm Pool (IPWP) during the Holocene epoch. Here we introduce a new leaf wax isotope record from Sulawesi, Indonesia and compare proxy water isotope data with ocean-atmosphere general circulation model (OAGCM) simulations to identify mechanisms influencing Holocene IPWP hydroclimate. Modeling simu...

Journal: :Proceedings. Biological sciences 2011
Christopher N Johnson Barry W Brook

Measuring trends in the size of prehistoric populations is fundamental to our understanding of the demography of ancient people and their responses to environmental change. Archaeologists commonly use the temporal distribution of radiocarbon dates to reconstruct population trends, but this can give a false picture of population growth because of the loss of evidence from older sites. We demonst...

2006
Takehiko R. Hashimoto Neil Saintilan TAKEHIKO R. HASHIMOTO NEIL SAINTILAN SIMON G. HABERLE

This paper describes the hitherto unreported occurrence of mid-Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of...

2013
Bianca B. Perren N. J. Anderson Marianne S. V. Douglas Sherilyn C. Fritz

Holocene paleolimnological records (diatoms, organic content, spectrally inferred sediment chlorophyll-a) from three West Greenland lakes (~67°N) situated along a transect from the outer coast to a nunatak at the periphery of the Greenland Ice Sheet are used to explore the nature of regional postglacial lake development and its relationship to Holocene climate evolution. The lakes were deglacia...

2005
Anil K. Gupta Moumita Das David M. Anderson

[1] The large (8%) changes in the past seasonal insolation have a well-documented influence on the Indian summer monsoon. However, the effect of the small (<1%) decade to century scale solar variability is less certain. Evidence is emerging that Earth’s climate is sensitive to small changes in solar output on centennial time scale during the Holocene. Comparison of a recently published proxy re...

2009
NICOLÁS E. YOUNG JASON P. BRINER DARRELL S. KAUFMAN

We reconstructed a chronology of glaciation spanning from the Late Pleistocene through the late Holocene for Fish Lake valley in the north-eastern Alaska Range using Be surface exposure dating and lichenometry. After it attained its maximum late Wisconsin extent, the Fish Lake valley glacier began to retreat ca. 16.5 ka, and then experienced a readvance or standstill at 11.6 0.3 ka. Evidence of...

2009
W. WYATT OSWALD DAVID R. FOSTER ELAINE D. DOUGHTY EDWARD K. FAISON

Analyses of a sediment core from Highstead Swamp in southwestern Connecticut, USA, reveal Lateglacial and early Holocene ecological and hydrological changes. Lateglacial pollen assemblages are dominated by Picea and Pinus subg. Pinus, and the onset of the Younger Dryas (YD) cold interval is evidenced by higher abundance of Abies and Alnus viridis subsp. crispa. As climate warmed at the end of t...

Journal: :Science 2003
Helge W Arz Frank Lamy Jurgen Pätzold Peter J Muller Maarten Prins

Paleosalinity and terrigenous sediment input changes reconstructed on two sediment cores from the northernmost Red Sea were used to infer hydrological changes at the southern margin of the Mediterranean climate zone during the Holocene. Between approximately 9.25 and 7.25 thousand years ago, about 3 per thousand reduced surface water salinities and enhanced fluvial sediment input suggest substa...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Pratigya J Polissar Mark B Abbott Alexander P Wolfe Mathias Vuille Maximiliano Bezada

Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in ...

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