TY - JOUR T1 - Deglacial temperature controls on no-analog community establishment in the Great Lakes Region JF - Quaternary Science Reviews Y1 - 2020 A1 - Fastovich, David A1 - Russell, James M. A1 - Jackson, Stephen T. A1 - Williams, John W. KW - biomarkers KW - brGDGT KW - Climate sensitivity KW - Lagoons & swamps KW - lakes KW - No-analog KW - North America KW - paleoclimatology KW - Pleistocene KW - pollen KW - sedimentology KW - Temperature KW - vegetation AB - Understanding the drivers of vegetation dynamics and no-analog communities in eastern North America is hampered by a scarcity of independent temperature indicators. We present a new branched glycerol dialkyl glycerol tetraether (brGDGT) temperature record from Bonnet Lake, Ohio (18–8 ka) and report uncertainty estimates based on Bayesian linear regression and bootstrapping. We also reanalyze a previously published brGDGT record from Silver Lake, Ohio, using improved chromatographic methods. All pollen- and brGDGT-based temperature reconstructions showed qualitatively similar deglacial trends but varying magnitudes. Separating 5- and 6- methyl brGDGTs resulted in substantially lower estimates of deglacial temperature variations (6.4 °C) than inferred from earlier brGDGT methods and pollen (11.8 °C, 12.0 °C respectively). Similar trends among proxies suggest good fidelity of brGDGTs to temperature, despite calibration uncertainties. At both sites, the rise and decline of no-analog communities closely track brGDGT-inferred temperatures, with a lag of 0–150 years. The timing of temperature and ecological events varies between Bonnet and Silver Lakes, likely due to age model uncertainties. Climate sensitivity analyses indicate a linear sensitivity of vegetation composition to temperature variations, albeit noisy and significant only with a 500-year bin. The formation of no-analog plant communities in the upper Midwest is closely linked to late-glacial warming, but other factors, such as temperature seasonality or end-Pleistocene megafaunal extinctions, remain viable. VL - 234 UR - https://linkinghub.elsevier.com/retrieve/pii/S0277379119303713 ER - TY - JOUR T1 - The nature of 'stone-lines' in the African Quaternary record: archaeological resolution at the rainforest site of Mosumu, Equatorial Guinea JF - Quaternary International Y1 - 2002 A1 - Mercader, J. A1 - Marti, R. A1 - Martinez, J. L. A1 - Brooks, A. KW - Age KW - behavior KW - cameroon KW - congo KW - ituri KW - layers KW - origin KW - tools KW - vegetation AB - 'Stone-lines' are widespread Quaternary features that appear in tropical and subtropical regions. They have a diverse nature and genesis, and are frequently associated with archaeological assemblages. However, archaeological deposition and 'stone-line' configuration may be unrelated geological events separated by thousands of years. The energetics involved in 'stone-line' formation, coarse and fine material translocation across space and in depth, and overall assemblage integrity vary from one site to another. This paper presents quantitative and spatial geoarchaeological data from the site of Mosumu, in the tropical rain forest of continental Equatorial Guinea. Mosumu yielded Middle and Later Stone Age assemblages dated to at least the last 30,000 years in a 'stone-line' context. Special attention to the study of vertical and horizontal variations of artifacts, sedimentary features, and taphonomic indicators allows analysis of the nature, meaning, and archeological resolution at this site. The results are placed in the wider debate over the meaning of 'stone-lines' in the African Quaternary record. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved. VL - 89 SN - 1040-6182 N1 - 536zcTimes Cited:15 Cited References Count:89 JO - Quatern Int ER - TY - JOUR T1 - Pollen record of the last 500 years from the Doninos coastal lagoon (NW Iberian Peninsula): Changes in the pollinic catchment size versus paleoecological interpretation JF - Journal of Coastal Research Y1 - 2001 A1 - Santos, L. A1 - Bao, R. A1 - Goni, M. F. S. KW - charcoal KW - coastal lagoon KW - diatoms KW - human impact KW - Late Holocene KW - late-holocene KW - nw iberian peninsula KW - pollen KW - representation KW - source area KW - vegetation KW - vegetation history AB - Pollen, diatom, charcoal and sedimentological analyses of a 4.20-m long core collected in the margin of the Doninos coastal lagoon, northwest Iberian Peninsula, provide information about the environmental evolution of this lagoon during the last 530 yr BP. During this time period, local environmental changes, such as changes in the sand-barrier permeability, alluvial sedimentation and/or anthropogenic activity, played a major role in the evolution of this coastal system. This scenario allows us to test the degree the pollinic signal recorded in the sediments of coastal lagoons is reshaped by the influence of local processes.Diatom and sedimentological data as well as historical archives indicate the development of a lacustrine system at the bottom of the sequence. Therefore, the coring site might be included in the lagoon itself. Pollen data seems to reflect the regional vegetation as a consequence of the large pollinic catchment area. Local Castanea cultivation and anthropogenic deforestation are also recorded. At the top of the sequence, diatom facies suggest increased marine influence at this time as a consequence of the more common events of breaching of a retrograding barrier. This, plus natural silting up by alluvial sedimentation and man-induced drying up of the lagoonal margins, lead to a progressive decrease in the water body extension. The coring point is now outside of the lagoon, implying a reduction in the pollinic catchment area that gave rise to a gradual increase in the local pollinic rainfall of periphytic vegetation. From the pollen diagram of this coastal deposit signatures of regional vegetation are swamped by local pollen input. The fluctuations in the percentages of the different pollen taxa are related to the complex interaction between basin size, human activities and breaching of the barrier. Caution must therefore be taken with direct paleoclimatic inferences from pollinic studies in coastal lagoons as an alternative where other continental deposits are lacking. VL - 17 SN - 0749-0208 IS - 3 N1 - 479bdTimes Cited:6 Cited References Count:46 JO - J Coastal Res ER -