Polygonal Patterned Ground in Central New Jersey

1978 ◽  
Vol 10 (1) ◽  
pp. 42-54 ◽  
Author(s):  
James C. Walters
Keyword(s):  
New Jersey ◽  
Last Glacial Maximum ◽  
Sandy Loam ◽  
Growing Season ◽  
Construction Sites ◽  
Differential Growth ◽  
Patterned Ground ◽  
Ice Wedge ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Polygonal patterned ground and associated sediment-filled wedges occur in thin-bedded shale in central New Jersey. During a dry growing season, numerous areas of polygonal ground were visible owing to differential growth of vegetation over the sediment-filled fractures. Construction sites where material was removed from the surface prior to excavation also revealed areas of polygonal ground. Measurements of the patterns show networks of polygons with diameters ranging from about 3 m to over 30 m, with an average of approximately 20 m. The wedges examined in vertical exposures range in depth from 25 to 260 cm (average, 125 cm) and in width from 10 to 240 cm (average, 50 cm). The infilling material of the wedges is mostly a sandy loam, although this material is not homogeneous throughout the wedges. The presence of ventifacts and frosted sand grains within the wedges indicates eolian activity during the formation of these features. The polygonal ground and wedge structures exhibit several characteristics similar to those of ice-wedge casts, and available evidence suggests they may have originated as ice-wedge polygons during the last glacial maximum.

Late Pleistocene and Holocene ice-wedge activity on the Blackstone Plateau, central Yukon, Canada

2018 ◽  
Vol 91 (1) ◽  
pp. 179-193 ◽  
Author(s):  
Mike Grinter ◽  
Denis Lacelle ◽  
Natalia Baranova ◽  
Sarah Murseli ◽  
Ian D. Clark
Keyword(s):  
Isotopic Composition ◽  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Environmental Conditions ◽  
Moisture Source ◽  
Ice Wedge ◽  
Western Arctic ◽  
Plateau Central ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractIce-wedge activity can be used to reconstruct past environmental conditions. We investigated the moisture source and timing of ice-wedge formation on the Blackstone Plateau. A section of permafrost exposed ice wedges that developed at two distinct depths: the first set formed syngenetically and penetrated alluvial silts from the top of permafrost; the second set, truncated by an erosional or thaw contact, was found solely in icy muddy gravels (>3.1 m depth). The δ18O and D-excess records of the ice wedges suggest that they formed from freezing of snow meltwater whose isotopic composition evolved during meltout. The14CDOCresults suggest that climate was favorable to ice-wedge growth between 32,000–30,000 and 14,000–12,500 cal yr BP, but there was likely a hiatus during the last glacial maximum due to climate being too dry. During the early to mid-Holocene, ice wedges were inactive as a result of warmer and wetter climate. Ice wedge re-initiated around 6360 cal yr BP, with a peak in activity between 3980 and 920 cal yr BP, a period characterized by cool and moist climate. Overall, timing of ice-wedge activity was broadly consistent with the climate and vegetation evolution in the western Arctic.

scholarly journals State Records and Habitat of Clam Shrimp, Caenestheriella gynecia (Crustacea: Conchostraca), in New York and New Jersey

2007 ◽  
Vol 121 (2) ◽  
pp. 128 ◽  
Author(s):  
Robert E. Schmidt ◽  
Erik Kiviat
Keyword(s):  
New York ◽  
New Jersey ◽  
Last Glacial Maximum ◽  
New Records ◽  
Hudson Valley ◽  
Parthenogenetic Species ◽  
Last Glacial ◽  
Clam Shrimp ◽  
The Last Glacial Maximum ◽  
The Last Glacial

We report new records of the Clam Shrimp, Caenestheriella gynecia Mattox 1950, from three localities in the Hudson Valley of New York and one locality in northeastern New Jersey. All of our specimens were collected in puddles on dirt roads. The New Jersey specimens have meristics that are well within the range of Caenestheriella Daday 1915; however, the eastern New York specimens resemble those reported from Massachusetts with meristics that are closer to Cyzicus Audouin 1837. We hypothesize that C. gynecia was established as a parthenogenetic species due to an unlikely dispersal event in the western part of its range and has migrated eastward since the last glacial maximum. Dispersal of this species may occur by wind, in the gut of birds, or stuck to animal feet or fur, or to vehicles. We recommend that C. gynecia be treated as rare and vulnerable to extinction throughout its range unless demonstrated otherwise.

scholarly journals Climate, CO2, and the history of North American grasses since the Last Glacial Maximum

2016 ◽  
Vol 2 (3) ◽  
pp. e1501346 ◽  
Author(s):  
Jennifer M. Cotton ◽  
Thure E. Cerling ◽  
Kathryn A. Hoppe ◽  
Thomas M. Mosier ◽  
Christopher J. Still
Keyword(s):  
North America ◽  
Last Glacial Maximum ◽  
Growing Season ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Cart Analysis ◽  
Landscape Models ◽  
The Last Glacial Maximum ◽  
Growing Season Precipitation ◽  
The Last Glacial

The spread of C4grasses in the late Neogene is one of the most important ecological transitions of the Cenozoic, but the primary driver of this global expansion is widely debated. We use the stable carbon isotopic composition (δ13C) of bison and mammoth tissues as a proxy for the relative abundance of C3and C4vegetation in their grazing habitat to determine climatic and atmospheric CO2controls on C4grass distributions from the Last Glacial Maximum (LGM) to the present. We predict the spatial variability of grass δ13C in North America using a mean of three different methods of classification and regression tree (CART) machine learning techniques and nine climatic variables. We show that growing season precipitation and temperature are the strongest predictors of all single climate variables. We apply this CART analysis to high-resolution gridded climate data and Coupled Model Intercomparison Project (CMIP5) mean paleoclimate model outputs to produce predictive isotope landscape models (“isoscapes”) for the current, mid-Holocene, and LGM average δ13C of grass-dominated areas across North America. From the LGM to the present, C4grass abundances substantially increased in the Great Plains despite concurrent increases in atmospheric CO2. These results suggest that changes in growing season precipitation rather than atmospheric CO2were critically important in the Neogene expansion of C4grasses.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

WASATCH RANGE, UT GLACIER RECONSTRUCTIONS FOR THE LAST GLACIAL MAXIMUM AND LATEGLACIAL

2017 ◽  
Author(s):  
Brendon J. Quirk ◽  
◽  
Jeffrey R. Moore ◽  
Benjamin J. Laabs ◽  
Mitchell A. Plummer ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial
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