scholarly journals The age of Clovis—13,050 to 12,750 cal yr B.P.

2020 ◽  
Vol 6 (43) ◽  
pp. eaaz0455
Author(s):  
Michael R. Waters ◽  
Thomas W. Stafford ◽  
David L. Carlson
Keyword(s):  
North American ◽  
Younger Dryas ◽  
Southern Cone ◽  
Western Hemisphere ◽  
Western North America ◽  
Projectile Points ◽  
Bone Charcoal ◽  
Plant Remains ◽  
Terminal Pleistocene ◽  
Age Range

Thirty-two radiocarbon ages on bone, charcoal, and carbonized plant remains from 10 Clovis sites range from 11,110 ± 40 to 10,820 ± 10 14C years before the present (yr B.P.). These radiocarbon ages provide a maximum calibrated (cal) age range for Clovis of ~13,050 to ~12,750 cal yr B.P. This radiocarbon record suggests that Clovis first appeared at the end of the Allerød and is one of at least three contemporary archaeological complexes in the Western Hemisphere during the terminal Pleistocene. Stemmed projectile points in western North America are coeval and even older than Clovis, and the Fishtail point complex is well established in the southern cone of South America by ~12,900 cal yr B.P. Clovis disappeared ~12,750 cal yr B.P. at the beginning of the Younger Dryas, coincident with the extinction of the remaining North American megafauna (Proboscideans) and the appearance of multiple North American regional archaeological complexes.

Geographic Variation in Fluted Projectile Points: A Hemispheric Perspective

1999 ◽  
Vol 64 (2) ◽  
pp. 215-230 ◽  
Author(s):  
Juliet E. Morrow ◽  
Toby A. Morrow
Keyword(s):  
North America ◽  
South America ◽  
Geographic Variation ◽  
Great Plains ◽  
North American ◽  
South American ◽  
Western North America ◽  
Radiocarbon Dates ◽  
Projectile Points ◽  
Fluted Points

This paper examines geographic variation in fluted point morphology across North and South America. Metric data on 449 North American points, 31 Central American points, and 61 South American points were entered into a database. Ratios calculated from these metric attributes are used to quantify aspects of point shape across the two continents. The results of this analysis indicate gradual, progressive changes in fluted point outline shape from the Great Plains of western North America into adjacent parts of North America as well as into Central and South America. The South American “Fishtail” form of fluted point is seen as the culmination of incremental changes in point shape that began well into North America. A geographically gradual decline in fluting frequency also is consistent with the stylistic evolution of the stemmed “Fishtail” points. Although few in number, the available radiocarbon dates do suggest that “Fishtail” fluted points in southern South America are younger than the earliest dates associated with Clovis points in western North America. All of these data converge on the conclusion that South American “Fishtail” points evolved from North American fluted points.

scholarly journals Inter- and Intra-Continental Genetic Variation in the Generalist Conifer Wood Saprobic Fungus Phlebiopsis gigantea

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 751
Author(s):  
Francesco Dovana ◽  
Paolo Gonthier ◽  
Matteo Garbelotto
Keyword(s):  
North America ◽  
Genetic Differentiation ◽  
Dna Sequences ◽  
North American ◽  
Fungal Species ◽  
Coniferous Forests ◽  
Native Forest ◽  
Western North America ◽  
Phlebiopsis Gigantea ◽  
Conifer Wood

Phlebiopsis gigantea (Fr.) Jülich is a well-known generalist conifer wood saprobe and a biocontrol fungus used in several world countries to prevent stump infection by tree pathogenic Heterobasidion fungal species. Previous studies have reported the presence of regional and continental genetic differentiation in host-specific fungi, but the presence of such differentiation for generalist wood saprobes such as P. gigantea has not been often studied or demonstrated. Additionally, little information exists on the distribution of this fungus in western North America. The main purposes of this study were: (I) to assess the presence of P. gigantea in California, (II) to explore the genetic variability of P. gigantea at the intra and inter-continental levels and (III) to analyze the phylogeographic relationships between American and European populations. Seven loci (nrITS, ML5–ML6, ATP6, RPB1, RPB2, GPD and TEF1-α) from 26 isolates of P. gigantea from coniferous forests in diverse geographic distribution and from different hosts were analyzed in this study together with 45 GenBank sequences. One hundred seventy-four new sequences were generated using either universal or specific primers designed in this study. The mitochondrial ML5–ML6 DNA and ATP6 regions were highly conserved and did not show differences between any of the isolates. Conversely, DNA sequences from the ITS, RPB1, RPB2, GPD and TEF1-α loci were variable among samples. Maximum likelihood analysis of GPD and TEF1-α strongly supported the presences of two different subgroups within the species but without congruence or geographic partition, suggesting the presence of retained ancestral polymorphisms. RPB1 and RPB2 sequences separated European isolates from American ones, while the GPD locus separated western North American samples from eastern North American ones. This study reports the presence of P. gigantea in California for the first time using DNA-based confirmation and identifies two older genetically distinct subspecific groups, as well as three genetically differentiated lineages within the species: one from Europe, one from eastern North America and one from California, with the latter presumably including individuals from the rest of western North America. The genetic differentiation identified here among P. gigantea individuals from coniferous forests from different world regions indicates that European isolates of this fungus should not be used in North America (or vice versa), and, likewise, commercially available eastern North American P. gigantea isolates should not be used in western North America forests. The reported lack of host specificity of P. gigantea was documented by the field survey and further reinforces the need to only use local isolates of this biocontrol fungus, given that genetically distinct exotic genotypes of a broad generalist microbe may easily spread and permanently alter the microbial biodiversity of native forest ecosystems.

Sophistry, Security, and Socio-Political Structures in the American Revolution; or, Why Jamaica did not Rebel

1986 ◽  
Vol 29 (2) ◽  
pp. 319-344 ◽  
Author(s):  
T. R. Clayton
Keyword(s):  
North America ◽  
British Empire ◽  
American Revolution ◽  
North American ◽  
Western Hemisphere ◽  
American Colonies ◽  
Constitutional Principle ◽  
Mother Country ◽  
Political Structures

Britain's most important American colonies did not rebel in 1776. Thirteen provinces did declare their independence; but no fewer than nineteen colonies in the western hemisphere remained loyal to the mother country. Massachusetts and Virginia may have led the American revolution, but they had never been the leading colonies of the British empire. From the imperial standpoint, the significance of any of the thirteen provinces which rebelled was pale in comparison with that of Jamaica or Barbados. In the century before 1763 the recalcitrance of these two colonies had been more notorious than that of any mainland province and had actually inspired many of the imperial policies cited as long-term grievances by North American patriots in 1774. Real Whig ideology, which some historians have seen as the key to understanding the American revolution, was equally understood by Caribbean elites who, like the continental, had often proved extremely sensitive on questions of constitutional principle. Attacks of ‘frenzied rhetoric’ broke out in Jamaica in 1766 and Barbados in 1776. But these had nothing whatsoever to do with the Stamp Act or events in North America.

Precise cosmogenic 10Be measurements in western North America: Support for a global Younger Dryas cooling event

Geology ◽  
1995 ◽  
Vol 23 (10) ◽  
pp. 877 ◽  
Author(s):  
J. C. Gosse ◽  
E. B. Evenson ◽  
J. Klein ◽  
B. Lawn ◽  
R. Middleton
Keyword(s):  
North America ◽  
Younger Dryas ◽  
Western North America ◽  
Cosmogenic 10Be

scholarly journals J.T.A.H. Special Publication #3 Appendix to Cover Art, The Journal of Texas Archeology and History Volume 4 (2017/2018): A Visual Guide to the Archaic Points Found at the Gault Site (41BL323) with Clovis Points for Comparison; including Projectile Point Fact Sheets

2018 ◽  
Author(s):  
Thomas Williams
Keyword(s):  
Raw Materials ◽  
Archaeological Site ◽  
Western Hemisphere ◽  
Archaeological Research ◽  
Projectile Point ◽  
Non Profit ◽  
Projectile Points ◽  
Central Texas ◽  
Cover Art ◽  
Archaeological Excavations

Archaeological excavations at the Gault Archaeological Site (41BL323) have revealed an almost complete stratigraphic record of the prehistoric occupation of Central Texas (Collins 2002, 2004). Furthermore, ages obtained from Area 15 of the site confirms good stratigraphic agreement between the diagnostic artifacts, cultural horizons, and stratigraphic units (Rodrigues, et al. 2016; Williams, et al. 2018). This includes some of the earliest evidence for a projectile point technology in North America (Williams, et al. 2018). Like many areas in Central Texas, the combination of water, raw materials, and its position along the Balcones Escarpment provided abundant resources essential to survival. The Gault Archaeological Site has a long history. The site takes its name from a previous landowner, Henry Gault, and the first scientific excavations were conducted there in 1929 under the supervision of J. E. Pearce. In 1990, David Olmstead reported a unique find; an Alibates Clovis point sandwiched between two limestone plaques with engraved geometric designs. This led to a site visit by Dr. Tom Hester and Dr. Michael Collins. This finding was followed in 1997 by the discovery of an extremely fragile mandible of a juvenile mammoth by the Lindsey family. These discoveries prompted the recent archaeological excavations at the site, which began in 1999 and lasted until 2002. As many archaeologists will attest, the most interesting findings came at the very end of the 2002 field season, when archaeologist Sam Gardner exposed cultural material stratigraphically below Clovis in a small test unit. This led to negotiations between Michael Collins and the Lindsey family that resulted in the purchase of the property by Dr. Collins and its donation to the Archaeological Conservancy. Between 2007-2014, Area 15 was excavated to expose the cultural materials below. With the cessation of excavations in 2014, research focuses on reporting these findings and how this early archaeological assemblage in Central Texas is redefining the search for the earliest human occupants of the Americas. The front cover of this issue of the Journal of Texas Archeology and History highlights two specific chronological periods in Texas. Firstly, in each corner you will find interactive 3D scans of four Clovis points that have been recovered from the site (Seldon et al. 2018). In between these, you will find and array of Archaic projectile points that have been recovered from the various excavations conducted between 1999-2002 and 2007-2014. This includes Early Archaic points such as the Hoxie and Martindale; Middle Archaic points including, Kinney and Nolan; and Late Archaic points including Pedernales, Marshall, and Bulverde. Clovis artifacts including, projectile points, blade cores, and diagnostic debitage have been recovered from a total of 9 excavation areas. We will expand on these covers in the future to cover specific research projects currently being undertaken by the Gault School of Archaeological Research staff. The Gault School of Archaeological Research is a non-profit, 501(C)3 charitable organization dedicated to innovative, interdisciplinary research archaeology and education focusing on the earliest peoples in the western hemisphere and their cultural antecedents. The reader is encouraged to “click” around on the various cover images comprising the front and back cover border artwork to find and explore the additional rich content hidden there. Click here to open or download an informative “Appendix to the Cover Art containing this article, descriptive attribute data and a larger image of all projectile points shown on the front and back covers.

scholarly journals Influence of ENSO on North American subseasonal surface air temperature variability

2021 ◽  
Vol 2 (2) ◽  
pp. 395-412
Author(s):  
Patrick Martineau ◽  
Hisashi Nakamura ◽  
Yu Kosaka
Keyword(s):  
North America ◽  
Air Temperature ◽  
North American ◽  
Surface Air Temperature ◽  
Tropical Pacific ◽  
La Niña ◽  
Western North America ◽  
The North ◽  
Subseasonal Variability ◽  
La Nina

Abstract. The wintertime influence of tropical Pacific sea surface temperature (SST) variability on subseasonal variability is revisited by identifying the dominant mode of covariability between 10–60 d band-pass-filtered surface air temperature (SAT) variability over the North American continent and winter-mean SST over the tropical Pacific. We find that the El Niño–Southern Oscillation (ENSO) explains a dominant fraction of the year-to-year changes in subseasonal SAT variability that are covarying with SST and thus likely more predictable. In agreement with previous studies, we find a tendency for La Niña conditions to enhance the subseasonal SAT variability over western North America. This modulation of subseasonal variability is achieved through interactions between subseasonal eddies and La Niña-related changes in the winter-mean circulation. Specifically, eastward-propagating quasi-stationary eddies over the North Pacific are more efficient in extracting energy from the mean flow through the baroclinic conversion during La Niña. Structural changes of these eddies are crucial to enhance the efficiency of the energy conversion via amplified downgradient heat fluxes that energize subseasonal eddy thermal anomalies. The enhanced likelihood of cold extremes over western North America is associated with both an increased subseasonal SAT variability and the cold winter-mean response to La Niña.

A New Gunnel, Pholis clemensi, from the Coast of Western North America

1964 ◽  
Vol 21 (5) ◽  
pp. 933-939 ◽  
Author(s):  
Richard H. Rosenblatt
Keyword(s):  
British Columbia ◽  
New Species ◽  
North America ◽  
North American ◽  
North American Species ◽  
Western North America ◽  
The North ◽  
The Family ◽  
Juan De Fuca ◽  
A New Species

A new species, Pholis clemensi, referred to the family Pholidae, is named and described from 12 specimens taken in southern British Columbia waters and the Strait of Juan de Fuca. Pholis clemensi is compared with other members of the genus, and a key is given to the North American species.

The Impact of Sea Surface Temperature Biases on North American Precipitation in a High-Resolution Climate Model

2020 ◽  
Vol 33 (6) ◽  
pp. 2427-2447 ◽  
Author(s):  
Nathaniel C. Johnson ◽  
Lakshmi Krishnamurthy ◽  
Andrew T. Wittenberg ◽  
Baoqiang Xiang ◽  
Gabriel A. Vecchi ◽  
...  
Keyword(s):  
North America ◽  
Surface Temperature ◽  
North Atlantic ◽  
North American ◽  
North Pacific ◽  
Climate Model ◽  
Sea Surface ◽  
Tropical Atlantic ◽  
Western North America ◽  
The North

AbstractPositive precipitation biases over western North America have remained a pervasive problem in the current generation of coupled global climate models. These biases are substantially reduced, however, in a version of the Geophysical Fluid Dynamics Laboratory Forecast-Oriented Low Ocean Resolution (FLOR) coupled climate model with systematic sea surface temperature (SST) biases artificially corrected through flux adjustment. This study examines how the SST biases in the Atlantic and Pacific Oceans contribute to the North American precipitation biases. Experiments with the FLOR model in which SST biases are removed in the Atlantic and Pacific are carried out to determine the contribution of SST errors in each basin to precipitation statistics over North America. Tropical and North Pacific SST biases have a strong impact on northern North American precipitation, while tropical Atlantic SST biases have a dominant impact on precipitation biases in southern North America, including the western United States. Most notably, negative SST biases in the tropical Atlantic in boreal winter induce an anomalously strong Aleutian low and a southward bias in the North Pacific storm track. In boreal summer, the negative SST biases induce a strengthened North Atlantic subtropical high and Great Plains low-level jet. Each of these impacts contributes to positive annual mean precipitation biases over western North America. Both North Pacific and North Atlantic SST biases induce SST biases in remote basins through dynamical pathways, so a complete attribution of the effects of SST biases on precipitation must account for both the local and remote impacts.

REVISION OF NORTH AMERICAN AGABUS LEACH (COLEOPTERA: DYTISCIDAE): THE OPACUS-GROUP

1996 ◽  
Vol 128 (4) ◽  
pp. 613-665 ◽  
Author(s):  
D.J. Larson
Keyword(s):  
North America ◽  
Phylogenetic Tree ◽  
North American ◽  
Western North America ◽  
Character Distribution ◽  
Distribution And Ecology

AbstractSpecies of the Agabus opacus- and lineellus-groups, as defined by Larson (1989), are combined and revised as members of the A. opacus-group. The A. opacus-group contains 13 species, namely: A. hypomelas Mannerheim, A. vancouverensis Leech, A. verisimilis Brown, A. vandykei Leech, A. wasastjernae (Sahlberg), A. opacus Aubé, A. confertus LeConte, A. euryomus sp.nov., A. walsinghami (Crotch), A. jimzim sp.nov., A. lineellus LeConte, A. discors LeConte, and A. austrodiscors sp.nov. Agabus wasastjernae and A. opacus are Holarctic and boreal; the remaining 11 species are confined to the Cordilleran region of western North America. Character distribution does not support recognition of subspecies of A. hypomelas, therefore A. hypomelas irregularis Mannerheim is regarded as a synonym of A. hypomelas. A lectotype is designated for A. discors LeConte. A phylogenetic tree of the hypothesized relationships between the species is presented.A key to the species of the group is included. For each species, the following information is provided: synonymy; description and illustration of taxonomically important characters; notes on relationships, variation, distribution, and ecology; and a map of North American collection localities.

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