bluuebunny/crossref_metadata_2025_split huggingface dataset:
Holocene Climate of New England
Authors: Davis Margaret B. , Spear Ray W. , Shane Linda C. K. 
Published: December 2004

AbstractStratigraphic studies of pollen and macrofossils from six sites at different elevations in the White Mountains of New Hampshire demonstrate changes in the distributions of four coniferous tree species during the Holocene. Two species presently confined to low elevations extended farther up the mountain slopes during the early Holocene: white pine grew 350 m above its present limit beginning 9000 yr B.P., while hemlock grew 300–400 m above its present limit soon after the species immigrated to the region 7000 yr. B.P. Hemlock disappeared from the highest sites about 5000 yr B.P., but both species persisted at sites 50–350 m above their present limits until the Little Ice Age began a few centuries ago. The history of the two main high-elevation conifers is more difficult to interpret. Spruce and fir first occur near their present upper limits 9000 or 10,000 yr B.P. Fir persisted in abundance at elevations similar to those where it occurs today throughout the Holocene, while spruce became infrequent at all elevations from the beginning of the Holocene until 2000 yr B.P. These facts suggest a more complex series of changes than a mere upward shift of the modern environmental gradient. Nevertheless, we conclude that the minimum climatic change which would explain the upward extensions of hemlock and white pine is a rise in temperature, perhaps as much as 2°C. The interval of maximum warmth started 9000 yr B.P. and lasted at least until 5000 yr B.P., correlative with the Prairie Period in Minnesota.
Towards a Quaternary Time Scale
Authors: Berggren W. A. , Burckle L. H. , Cita M. B. , Cooke H. B. S. , Funnell B. M. , Gartner S. , Hays J. D. , Kennett J. P. , Opdyke N. D. , Pastouret L. , Shackleton N. J. , Takayanagi Y. 
Published: December 2004

AbstractNine first-appearance datums (FADs), twenty-three last-appearance datums (LADs), and three other micropaleontological datums are related to the magnetic-reversal, oxygen-isotope, and calcite-dissolution/coarse-fraction time scales to provide a preliminary basis for subdivision of the Quaternary in deep-sea sediments. The magnetic-reversal, oxygen-isotope, and calcite-dissolution/coarse-fraction scales have been correlated by determination on the same core materials, and absolute dates applied by 40K/40Ar or 14C dating of materials in known positions on one or another of these scales. FADS and LADs have been determined in cores for which either a magnetic-reversal, oxygen-isotope, or calcite-dissolution/coarse-fraction scale has also been available. Altogether 3 FADs and 5 LADs based on diatoms, 4 FADs and 5 LADs based on calcareous nannoplankton, 1 FAD and 8 LADs based on radiolarians, 1 FAD and 5 LADs based on planktonic foraminifers, 2 acme datums, and 1 ratio reversal datum have been determined, and absolute dates inferred by interpolation from known dates on the reference time scales. Some of the FADs and LADs apply or are synchronous only over limited areas of the oceans; others appear to be synchronous throughout the oceans. The base of the Quaternary is set at the top of the Olduvai event at 1.7 my. Four FADs, twelve LADs, two acme datums, and one ratio reversal datum occur above the base of the Quaternary at an average rate of about 1 per 100,000 yr. Five FADs and twelve LADs are recognized in the 0.8-my interval between the top of the Olduvai event and the Gauss/Matuyama Boundary at 2.5 my at an average incidence of about 1 per 50,000 yr.
Ice-Sheet Glaciation of the Puget Lowland, Washington, during the Vashon Stade (Late Pleistocene)
Authors: Thorson Robert M. 
Published: December 2004

AbstractDuring the Vashon Stade of the Fraser Glaciation, about 15,000–13,000 yr B.P., a lobe of the Cordilleran Ice Sheet occupied the Puget lowland of western Washington. At its maximum extent about 14,000 yr ago, the ice sheet extended across the Puget lowland between the Cascade Range and Olympic Mountains and terminated about 80 km south of Seattle. Meltwater streams drained southwest to the Pacific Ocean and built broad outwash trains south of the ice margin. Reconstructed longitudinal profiles for the Puget lobe at its maximum extent are similar to the modern profile of Malaspina Glacier, Alaska, suggesting that the ice sheet may have been in a near-equilibrium state at the glacial maximum. Progressive northward retreat from the terminal zone was accompanied by the development of ice-marginal streams and proglacial lakes that drained southward during initial retreat, but northward during late Vashon time. Relatively rapid retreat of the Juan de Fuca lobe may have contributed to partial stagnation of the northwestern part of the Puget lobe. Final destruction of the Puget lobe occurred when the ice retreated north of Admiralty Inlet. The sea entered the Puget lowland at this time, allowing the deposition of glacial-marine sediments which now occur as high as 50 m altitude. These deposits, together with ice-marginal meltwater channels presumed to have formed above sea level during deglaciation, suggest that a significant amount of postglacial isostatic and(or) tectonic deformation has occurred in the Puget lowland since deglaciation.
Advance of the Late Wisconsin Cordilleran Ice Sheet in Southern British Columbia Since 22,000 Yr B.P.
Authors: Clague J. J. , Armstrong J. E. , Mathews W. H. 
Published: December 2004

AbstractRadiocarbon dates from critical stratigraphic localities in southern British Columbia indicate that the growth history of the late Wisconsin Cordilleran Ice Sheet was different from that of most of the Laurentide Ice Sheet to the east. Much of southern British Columbia remained free of ice until after about 19,000 to 20,000 yr ago; only adjacent to the Coast Mountains is there a record of lowland glacier tongues in the interval 22,000 to 20,000 yr B.P. A major advance to the climax of late Wisconsin Cordilleran glacier ice in the northern States was not begun until after about 18,000 yr B.P. in the southwest of British Columbia and after about 17,500 yr B.P. in the southeast. The rate of glacier growth must have been very rapid in the two to three millennia prior to the climax, which has been dated in western Washington at shortly after 15,000 yr B.P.
A Reexamination of Late-Pleistocene Boreal Forest Reconstructions for the Southern High Plains
Authors: Holliday Vance T. 
Published: December 2004

AbstractPrevious paleoecological research on the Southern High Plains resulted in development of a late Quaternary chronology of “pollen-analytical episodes” and the proposal that boreal forest existed in the region in the late Pleistocene. These interpretations are now considered untenable because (1) a number of the radiocarbon ages are questionable, (2) there are serious problems of differential pollen preservation and reproducibility of the pollen data, (3) there is an absence of supporting geological or paleontological data, and (4) the soils of the area contain none of the distinctive pedological characteristics produced by a boreal forest. Available data suggest that the region was primarily an open grassland or grassland with some nonconiferous trees through most of the Quaternary.
Mid-Holocene Climate in Northern Minnesota
Authors: Forester Richard M. , Delorme L. Denis , Bradbury J. Platt 
Published: December 2004

AbstractStudy of Holocene ostracodes and diatoms from Elk Lake, in North-Central Minnesota, indicates that the local climate of the mid-Holocene can be subdivided into three intervals. Throughout interval 1 (ca. 7800 to 6700 yr B.P.), climate was colder and much drier than today. During intervals 2 and 3 (ca. 6700 to 4000 yr B.P.) average mean-annual air temperatures approached the modern mean (3.7°C), but warm summers persisted throughout interval 2, whereas during interval 3 warm summers fell into discrete episodes. Furthermore, average mean-annual precipitation was about 85 and 90% of modern during intervals 2 and 3, respectively. Transition times between the principal intervals were less than 50 yr. The expected effects of a retreating Laurentide Ice Sheet that initially maintained a winter-style circulation, followed by transitional climate states, and finally a near-modern circulation pattern may explain these local climatic events.
Late Quaternary Stratigraphic Charcoal Records from Madagascar
Authors: Burney David A. 
Published: December 2004

AbstractThe classic view regarding the cause of the extinction of at least 17 species of large mammals, birds, and reptiles in Madagascar during the late Holocene implicates human use of fire to modify the environment. However, analysis of the charcoal stratigraphy of three sediment cores from Madagascar shows that late Pleistocene and early- to mid-Holocene sediments deposited prior to human settlement often contain more charcoal than postsettlement and modern sediments. This observation, which is confirmed by independent measurements from direct assay and palynological counting techniques, suggests that widely held but previously untested beliefs concerning the importance of anthropogenic fires in late Holocene environmental changes and megafaunal extinctions of Madagascar may be based on an overly simplified version of actual prehistoric conditions. Moderate to low charcoal values characterized only the late Holocene millennia immediately prior to the presumed time of arrival of the first settlers. Human settlement is probably indicated in the stratigraphy by the sharp rise in charcoal content observed beginning ca. 1500 yr B.P. Fire appears to be a significant natural component of prehuman environments in Madagascar, but some factor, probably climate, has modulated the extent of natural burning.
Spores of the Dung Fungus Sporormiella: Increased Abundance in Historic Sediments and Before Pleistocene Megafaunal Extinction
Authors: Davis Owen K. 
Published: December 2004

AbstractSpores of the dung fungus Sporormiella become abundant following the historic introduction of grazing herbivores at seven sites in the western United States. During the Holocene they are generally rare, but at six sites Sporormiella spores are abundant before the extinction of Pleistocene megaherbivores ca. 11,000 yr B.P. Sporormiella spores are directly linked to extinct megaherbivores by their presence in mammoth dung preserved in Bechan Cave, Southern Utah. Their abundance in late-glacial sediments may reflect the abundance of megaherbivores during Quaternary, thereby indicating the age of Pleistocene extinctions where other indicators are absent.
Time Scale of the Wisconsin/Holocene Transition: Oxygen Isotope Record in the Western Equatorial Pacific
Authors: Berger W. H. , Killingley J. S. , Vincent E. 
Published: December 2004

AbstractAn evaluation of both published and new oxygen isotope and radiocarbon data from the west equatorial Pacific (7 box cores, 2 piston cores, 2 gravity cores) indicates that there was no significant input of meltwater to the ocean before 14,000 14C yr B.P. This finding is in conflict with various early deglaciation scenarios suggested several years ago on the basis of Wisconsin/Holocene transition records from the Atlantic, but agrees with late-onset scenarios proposed more recently, both for Pacific and Atlantic deglaciation records.
Persistent Late Pleistocene-Holocene Seasonal Upwelling and Varves Off the Coast of California
Authors: Anderson Roger Y. , Hemphill-Haley Eileen , Gardner James V. 
Published: December 2004

AbstractSeasonal production of siliceous phytoplankton and a seasonal flux of terrigenous clastic material produced varved sediments along the continental slope off California during the late Pleistocene to mid-Holocene. Light-colored sediment within laminations and in sediment-trap samples was deposited during summer upwelling and contains an abundance of the diatoms Skeletonema costatum and Chaetoceros spp. resting spores. Dark-colored sediment deposited in the fall and winter contains abundant Thalassiosira pacifica, and has more terrigenous material. Distribution of diatoms in varves shows that seasonal upwelling has persisted along the California coast and has remained strongly seasonal since the late Pleistocene.
Ice-Wedge Casts and Relict Patterned Ground in Central Illinois and their Environmental Significance
Authors: Johnson W. Hilton 
Published: December 2004

AbstractSediment features and soil patterns indicate that permafrost developed beyond the late Wisconsinan (Woodfordian) ice margin in Illinois. Vertical wedge-shaped bodies in Woodfordian glacigenic deposits and buried by Woodfordian loess are interpreted to be ice-wedge casts. Large-scale patterned ground, common on the late Wisconsinan drift plain and on the Illinoian drift plain to the south and west, also is interpreted to be the result of ice-wedge formation. Permafrost extended to about 38° 30′ N latitude and formed during the interval from about 21,000 to 16,000 yr B.P. Formation and degradation of permafrost was time-transgressive, directly related to the ice-marginal climate, and probably restricted temporally to less than 1000 years at a site. The following environmental conditions are suggested near the ice margin: mean annual ground temperature −3°C; mean annual air temperature −6 ± 2°C; less precipitation than modern, particularly in winter; strong and likely dry wind systems; and relatively open vegetation with few woody plants.
Early Holocene pinyon (Pinus monophylla) in the northeastern Great Basin
Authors: Madsen David B. , Rhode David 
Published: December 2004

AbstractFine-grained excavation and analysis of a stratigraphic column from Danger Cave, northeastern Great Basin, suggests prehistoric hunter-gatherers were collecting and using singleleaf pinyon (Pinus monophylla) near the site for at least the last 7500 yr. Human use of the cave began after the retreat of Lake Bonneville from the Gilbert level, shortly before 10,000 yr B.P. In stratum 9, culturally deposited pine nut hulls appear in the sequence by about 7900 yr B.P. and are continuously present thereafter. A hull fragment in stratum 10 is directly dated to 7410 ± 120 yr B.P. These dates are at least 2000 yr earlier than expected by extrapolation to macrofossil records from the east-central and central Great Basin, and necessitate some revision of current biogeographical models of late Quaternary pinyon migration.
Paleoenvironments and Human Occupation in Late-Glacial Panama
Authors: Piperno Dolores R. , Bush Mark B. , Colinvaux Paul A. 
Published: December 2004

AbstractThe first pollen and phytolith data covering the entire Pleistocene/Holocene transition from the lowlands of the Central American isthmus indicate that the forests of late-glacial Panama at an altitude of 650 m resembled those currently found at ca. 1500–1800 m. A temperature depression of ca. 5°C and reduced precipitation/evaporation ratios in the late-glacial period are suggested. Forest composition from ca. 14,000 to 10,500 yr B.P., although primarily montane in character, contained a low biomass of species today segregated in lowland forests and, hence, a floral assemblage with no modern analog. The sudden appearance of carbon and burnt, weedy plant material at ca. 11,000 yr B.P. is attributed to the earliest human impact yet recorded from tropical America and may perhaps have been associated with the first human occupation of the region.
Accelerator Dating of a Mixed Assemblage of Late Pleistocene Insect Fossils from the Lamb Spring Site, Colorado
Authors: Elias Scott A. , Toolin Laurence J. 
Published: December 2004

AbstractFossil insects from the late-glacial deposits at the Lamb Spring archaeological site, near Denver, Colorado, are relatively abundant and diverse, providing considerable paleoecological data for the site. The late Pleistocene insect fauna from the site comprises 72 identified taxa, principally beetles. However, the fauna presented an interpretive problem because it contained a mixture of prairie and alpine tundra species. This was initially considered to be the result of a mixing of faunal elements during the climatic transition of late-glacial times, a “no-modern-analog” fauna. Accelerator dating of insect fossil specimens from the two ecological groups helped resolve the paleoecological problem. Fossil specimens of the prairie-associated species were dated at 17,850 ± 550 yr B.P., while specimens of the tundra-associated species yielded an age of 14,500 ± 500 yr B.P. These dates reveal that what appeared to be an ecological mixing was probably a taphonomic problem, wherein full-glacial-age fossils were probably reworked into latest Wisconsin sediments. While both faunal assemblages reflect climatic conditions substantially colder than present, initial results suggest that the full-glacial fauna represents a cold, dry grassland or steppe environment, while the younger fauna suggests moister and more tundra-like conditions.
Late Weichselian Glacier Retreat in Kongsfjorden, West Spitsbergen, Svalbard
Authors: Lehman Scott J. , Forman Steven L. 
Published: December 2004

AbstractThe chronology of Late Weichselian to Holocene deglaciation of Kongsfjorden, west Spitsbergen has been reconstructed based on the geomorphic and stratigraphic record of ice retreat, relative sea-level relationships, and 14C dating of associated marine organic materials. The seaward extent of glacial drift and fjord bathymetry constrain a secure reconstruction for the ice sheet near the mouth of the fjord at ca. 13,000 yr B.P., but do not rule out the possibility that more extensive glaciation was achieved earlier during the Late Weichselian. Regional shoreline relations, rates of emergence, and radiocarbon dating of foraminifera deposited just above till indicate that deglaciation occurred in two steps: one beginning during or just prior to the Late Weichselian Marine Limit phase at 13,000–12,000 yr B.P. and another beginning at 10,000–9500 yr B.P. The fjord was completely deglaciated by 9440 ± 130 yr B.P. A period of stable relative sea level began 10,700 yr B.P. and ended between 10,000 and 9500 yr B.P., which we take to indicate renewed glacial loading during the Younger Dryas. Glacier readvance within Kongsfjorden at this time was diminutive, suggesting that most of the Younger Dryas ice-sheet growth was confined to the eastern part of the archipelago and/or to the Barents Shelf. The two-step deglaciation of Kongsfjorden occurred during intervals of accelerated global ice-sheet melting and rapid oceanic and atmospheric warming in more temperate latitudes of the circum-Atlantic region. This coincidence most likely resulted from contemporaneous increases in the poleward transport of oceanic heat.
Mictomys Borealis(Northern Bog Lemming) and the Wisconsin Paleoecology of the East-Central Great Basin
Authors: Mead Jim I. , Bell Christopher J. , Murray Lyndon K. 
Published: December 2004

AbstractTeeth of northern bog lemming,Mictomys borealis, are reported from Cathedral and Smith Creek caves and represent the first Wisconsin remains of the genus from the Great Basin. Specimens from Cathedral Cave, Snake Range, are associated with U-series ages of 24,000 to 15,000 yr B.P. Previous work with pollen and packrat middens, dating to the same age as theMictomys, indicate that Smith Creek Canyon contained a riparian, locally mesic community, includingPicea engelmannii(spruce),Betulasp. (birch),Cercocarpussp. (mountain mahogany), andArtemisiasp. (sagebrush) among other species. Exposed canyon slopes and the adjacent valley apparently contained a more xeric steppe community including sagebrush and Chenopodiineae species; rocky outcrop permittedPinus flexilis(limber pine) andP. longaeva(bristlecone pine) to grow adjacent to Lake Bonneville or low in the canyon. The region apparently experienced a dry climate (not necessarily drier than today); however, Smith Creek Canyon was fed by glacial meltwater from Mt. Moriah. The northern bog lemming probably lived only in the riparian community and possibly on the north-facing slope below Cathedral Cave. Few canyons of the Snake Range would have had the unusually mesic conditions found in Smith Creek Canyon.
Circumpolar Distribution of Holocene Marine Fossils in Antarctic Beaches
Authors: Berkman Paul Arthur 
Published: December 2004

AbstractThe composite frequency of radiocarbon ages for Holocene marine fossils from beaches around Antarctica is significantly different than random. Variations in the frequency of fossil ages coincide with the timing of Holocene climate changes inferred from Antarctic ice cores, sub-Antarctic lakes, polar and alpine moraines, and sea level. Extant Antarctic marine species that occur as fossils in beaches may reflect coastal meltwater impacts associated with ice sheet marginal fluctuations that were circumpolar during the Holocene.
Circulating and synovial levels of IGF‐I, cytokines, physical function and anthropometry differ in women awaiting total knee arthroplasty when compared to men
Authors: Pagura Sonia M. C. , Thomas Scott G. , Woodhouse Linda J. , Ezzat Shereen , Marks Paul 
Published: December 2004

AbstractPurpose: Determine if gender differences in osteoarthritis relate to cytokine and growth factor levels.Methods: Cross‐sectional comparison of serum and synovial concentrations of cytokines (IL‐1αβ, TNF‐α, IL‐6), growth factors (IGF‐I, TGF‐β, IRAP), physical performance and perceived function in total knee arthroplasty candidates (TKAC) (n = 17) and healthy controls (n = 21) was done.Results: Serum IGF‐I values were reduced in female (TKAC 137.6 ± 7.2; Controls 160.2 ± 26.2) but not male TKAC (TKAC 182.6 ± 18.4; Controls 184.0 ± 18.4) (p < 0.05). Serum and synovial levels of cytokines and growth factors did not differ significantly by group or gender. Physical performance testing (SPW, TUG) revealed significant group and gender differences (p = 0.001) with women demonstrating greater functional impairment.Discussion: A systemic, not local component to OA pathophysiology may exist for female TKAC. Male TKAC were less impaired, and their IGF‐I levels differ little from Control values. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
In vivo assessment of regenerate axial stiffness in distraction osteogenesis
Authors: Aarnes Gudrun Trøite , Steen Harald , Ludvigsen Per , Waanders Nicholas A. , Huiskes Rik , Goldstein Steven A. 
Published: December 2004

AbstractThis paper presents an in vivo test for assessment of regenerate axial stiffness after the distraction phase of lengthening therapy. The test result supplements radiography in evaluating bone healing and assists in determining when the regenerate stiffness is sufficient for removal of the external fixator. The test is non‐invasive and does not require fixator removal. The theoretical basis for the method is that an externally applied load is shared between the fixator and the regenerating bone. The amount of load carried by the regenerate depends on its axial stiffness, which increases with advanced mineralization. By measuring the force in the fixator while applying a known external load to the limb, the load‐share ratio between fixator and limb can be assessed. A load‐share ratio of 100% indicates that the entire load is carried by the fixator. The ratio decreases as the regenerate structure gradually stiffens. In a clinical trial of 22 individuals with tibial lengthening, the fixator was removed when the load‐share ratio dropped below 10%. None of the patients experienced fracture after removal of the fixator. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.