Comment: A Last Glacial Maximum pollen record from Bodmin Moor showing a possible cryptic northern refugium in southwest England. (Kelly et al., 2010)

2010 ◽  
Vol 25 (5) ◽  
pp. 826-827 ◽  
Author(s):  
James Scourse
2020 ◽  
pp. 1-15
Author(s):  
Peter C. Almond ◽  
Sándor Gulyás ◽  
Pál Sümegi ◽  
Balázs P. Sümegi ◽  
Stephen Covey-Crump ◽  
...  

Abstract Calcareous loess in North Canterbury, eastern South Island, New Zealand (NZ), preserves subfossil bird bone, terrestrial gastropods, and eggshell, whose abundances and radiocarbon ages allowed us to reconstruct aspects of palaeoenvironment at high resolution through 25 to 21 cal ka BP. This interval includes millennial-scale climatic variability during the extended last glacial maximum (30–18 ka) of Australasia. Our loess palaeoclimatic record shows good correspondence with stadial and interstadial climate events of the NZ Climate Event Stratigraphy, which were defined from a pollen record on the western side of South Island. An interstade from 25.4 to 24 cal ka BP was warm but also relatively humid on eastern South Island, and loess grain size may indicate reduced vigour of the Southern Hemisphere westerly winds. The subsequent stade (24–22.6 cal ka BP) was drier, colder, and probably windier. The next interstade remained relatively dry on eastern South Island, and westerly winds remained vigorous. The 25.4–24 ka interstade is synchronous with Heinrich stade 2, which may have driven a southward migration of the subtropical front, leading to warming and wetting of northern and central South Island and retreat of Southern Alps glaciers at ca. 26.5 ka.


1999 ◽  
Vol 52 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Sara Hotchkiss ◽  
James O. Juvik

A pollen record from Ka‘au Crater, O‘ahu, Hawai‘i contains evidence for changes in vegetation and climate since about 28,000 14C yr B.P. Zone 1 (ca. 28,100–ca. 22,800 14C yr B.P.) has pollen of dry to mesic forest species, including Pipturus-type, Dodonaea viscosa, Acacia koa, Chenopodium oahuense, Claoxylon sandwicense, Myrsine, and Metrosideros-type. In zone 2 (ca. 22,800–ca. 16,200 14C yr B.P.) Myrsine and Coprosma increase, with herbs, fern allies, and Grammitidaceae suggesting open canopies. Zone 3 (ca. 16,200–ca. 9700 14C yr B.P.) has pollen of wet forest species, including Freycinetia arborea, abundant Pritchardia, and Metrosideros-type. Zone 4 (ca. 9700–ca. 7000 14C yr B.P.) is similar, with less Pritchardia and more Metrosideros-type.Climate reconstruction was based on modern climatic ranges of flowering plants and an index derived from abundance of pollen in surface samples. Both methods agree on a qualitative reconstruction, although the ages are poorly constrained: 28,000–25,000 14C yr B.P. cool and dry; 25,000–23,000 14C yr B.P. dry and warmer; 23,000–20,000 14C yr B.P. moderately dry with declining temperature; 20,000–16,000 14C yr B.P. moderately dry and cool; 16,000–9000 14C yr B.P. warm and wet; 9000–7000 14C yr B.P. warm and possibly drier. Lower precipitation at Ka‘au Crater during the late glacial period and last glacial maximum is consistent with the interpretation that the North Pacific subtropical anticyclone was south of its present position. The pollen-derived temperature index yields an estimate of 3°–5°C temperature depression during the last glacial maximum.


2021 ◽  
Author(s):  
Chenzhi Li ◽  
Anne Dallmeyer ◽  
Thomas Böhmer ◽  
Alexander Postl ◽  
Ulrike Herzschuh

<p>Fossil pollen datasets can help to understand the temporal and spatial distribution patterns and driving forces of the past terrestrial biomes in high northern latitudes. Here we present a global pollen dataset since the Last Glacial Maximum, synthesized from 2821 palynological records from the Neotoma Paleoecology Database and additional literature. All terrestrial pollen taxa were taxonomically harmonized on genus (woody taxa) or family level (herb taxa) and temporally standardized by using a defined parameter setting for Bayesian age-depth modeling based on 14C dating. The age-depth models were statistically compared with existing models for each record. With a biomization approach, we reconstructed biomes for several time-slices throughout the last 22000 years with a temporal resolution of roughly 500 years. The reconstructed biome distributions are compared to simulated biome distributions inferred from a transient simulation for the last 25000 years, performed in the comprehensive Earth System Model of the Max Planck Institute (MPI-ESM). The overall biome trend agrees well, but the simulation shows lower forest cover in the high northern latitudes and reaches the maximum forest cover in the Holocene much earlier than the reconstructions indicate.</p>


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