scholarly journals Role of Large‐Scale Tectonic Forces in Intraplate Earthquakes of Central and Eastern North America

2019 ◽  
Vol 20 (4) ◽  
pp. 2134-2156 ◽  
Author(s):  
Attreyee Ghosh ◽  
William E. Holt ◽  
Alireza Bahadori
Keyword(s):  
North America ◽  
Large Scale ◽  
Eastern North America ◽  
Intraplate Earthquakes ◽  
Tectonic Forces

Agricultural Innovation and Dispersal in Eastern North America

2019 ◽  
Author(s):  
Kandace D. Hollenbach ◽  
Stephen B. Carmody
Keyword(s):  
North America ◽  
Behavioral Ecology ◽  
Large Scale ◽  
Human Behavioral Ecology ◽  
Archaic Period ◽  
Cultivated Plants ◽  
Plant Domestication ◽  
Eastern North America ◽  
Late Archaic ◽  
Native Peoples

The possibility that native peoples in eastern North America had cultivated plants prior to the introduction of maize was first raised in 1924. Scant evidence was available to support this speculation, however, until the “flotation revolution” of the 1960s and 1970s. As archaeologists involved in large-scale projects began implementing flotation, paleoethnobotanists soon had hundreds of samples and thousands of seeds that demonstrated that indigenous peoples grew a suite of crops, including cucurbit squashes and gourds, sunflower, sumpweed, and chenopod, which displayed signs of domestication. The application of accelerator mass spectrometry (AMS) dating to cucurbit rinds and seeds in the 1980s placed the domestication of these four crops in the Late Archaic period 5000–3800 bp. The presence of wild cucurbits during earlier Archaic periods lent weight to the argument that native peoples in eastern North America domesticated these plants independently of early cultivators in Mesoamerica. Analyses of DNA from chenopods and cucurbits in the 2010s definitively demonstrated that these crops developed from local lineages. With evidence in hand that refuted notions of the diffusion of plant domestication from Mesoamerica, models developed in the 1980s for the transition from foraging to farming in the Eastern Woodlands emphasized the coevolutionary relationship between people and these crop plants. As Archaic-period groups began to occupy river valleys more intensively, in part due to changing climatic patterns during the mid-Holocene that created more stable river systems, their activities created disturbed areas in which these weedy plants thrive. With these useful plants available as more productive stands in closer proximity to base camps, people increasingly used the plants, which in turn responded to people’s selection. Critics noted that these models left little room for intentionality or innovation on the part of early farmers. Models derived from human behavioral ecology explore the circumstances in which foragers choose to start using these small-seeded plants in greater quantities. In contrast to the resource-rich valley settings of the coevolutionary models, human behavioral ecology models posit that foragers would only use these plants, which provide relatively few calories per time spent obtaining them, when existing resources could no longer support growing populations. In these scenarios, Late Archaic peoples cultivated these crops as insurance against shortages in nut supplies. Despite their apparent differences, current iterations of both models recognize humans as agents who actively change their environments, with intentional and unintentional results. Both also are concerned with understanding the social and ecological contexts within which people began cultivating and eventually domesticating plants. The “when” and “where” questions of domestication in eastern North America are relatively well established, although researchers continue to fill significant gaps in geographic data. These primarily include regions where large-scale contract archaeology projects have not been conducted. Researchers are also actively debating the “how” and “why” of domestication, but the cultural ramifications of the transition from foraging to farming have yet to be meaningfully incorporated into the archaeological understanding of the region. The significance of these native crops to the economies of Late Archaic and subsequent Early and Middle Woodland peoples is poorly understood and often woefully underestimated by researchers. The socioeconomic roles of these native crops to past peoples, as well as the possibilities for farmers and cooks to incorporate them into their practices in the early 21st century, are exciting areas for new research.

scholarly journals Geographic Distribution of Cryptic Species of Plasmopara viticola Causing Downy Mildew on Wild and Cultivated Grape in Eastern North America

2014 ◽  
Vol 104 (7) ◽  
pp. 692-701 ◽  
Author(s):  
Mélanie Rouxel ◽  
Pere Mestre ◽  
Anton Baudoin ◽  
Odile Carisse ◽  
Laurent Delière ◽  
...  
Keyword(s):  
North America ◽  
Cryptic Species ◽  
Downy Mildew ◽  
Geographic Distribution ◽  
Host Species ◽  
Large Scale ◽  
Plasmopara Viticola ◽  
Eastern North America ◽  
Grape Downy Mildew ◽  
Parthenocissus Quinquefolia

The putative center of origin of Plasmopara viticola, the causal agent of grape downy mildew, is eastern North America, where it has been described on several members of the family Vitaceae (e.g., Vitis spp., Parthenocissus spp., and Ampelopsis spp.). We have completed the first large-scale sampling of P. viticola isolates across a range of wild and cultivated host species distributed throughout the above region. Sequencing results of four partial genes indicated the presence of a new P. viticola species on Vitis vulpina in Virginia, adding to the four cryptic species of P. viticola recently recorded. The phylogenetic analysis also indicated that the P. viticola species found on Parthenocissus quinquefolia in North America is identical to Plasmopara muralis in Europe. The geographic distribution and host range of five pathogen species was determined through analysis of the internal transcribed spacer polymorphism of 896 isolates of P. viticola. Among three P. viticola species found on cultivated grape, one was restricted to Vitis interspecific hybrids within the northern part of eastern North America. A second species was recovered from V. vinifera and V. labrusca, and was distributed across most of the sampled region. A third species, although less abundant, was distributed across a larger geographical range, including the southern part of eastern North America. P. viticola clade aestivalis predominated (83% of isolates) in vineyards of the European winegrape V. vinifera within the sampled area, indicating that a single pathogen species may represent the primary threat to the European host species within eastern North America.

Clarifying the role of fire in the deciduous forests of eastern North America: reply to Matlack

2015 ◽  
Vol 29 (3) ◽  
pp. 942-946 ◽  
Author(s):  
Michael C. Stambaugh ◽  
J. Morgan Varner ◽  
Reed F. Noss ◽  
Daniel C. Dey ◽  
Norman L. Christensen ◽  
...  
Keyword(s):  
North America ◽  
Deciduous Forests ◽  
Eastern North America

scholarly journals Trace fossils on dinosaur bones reveal ecosystem dynamics along the coast of eastern North America during the latest Cretaceous

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4973
Author(s):  
Chase D. Brownstein
Keyword(s):  
North America ◽  
Marine Invertebrates ◽  
Atlantic Coastal Plain ◽  
Ecosystem Dynamics ◽  
Eastern North America ◽  
Marine Deposits ◽  
Terrestrial Vertebrate ◽  
Atlantic Coastal ◽  
Tibia Shaft

Direct evidence of paleoecological processes is often rare when the fossil record is poor, as in the case of the Cretaceous of eastern North America. Here, I describe a femur and partial tibia shaft assignable to theropods from two Late Cretaceous sites in New Jersey. The former, identifiable as the femur of a large ornithomimosaur, bears several scores interpreted as shark feeding traces. The tibia shaft has punctures and flaked bone from the bites of mid-sized crocodyliforms, the first documented occurrence of crocodyliform traces on dinosaur bone from the Maastrichtian of the Atlantic Coastal Plain. The surface of the partial tibia is also littered with indentations interpreted as the traces of invertebrates, revealing a microcosm of biological interaction on the coastal seafloor of the Cretaceous Atlantic Ocean. Massive crocodyliforms, such as Deinosuchus rugosus and the slightly smaller Deltasuchus motherali, maintained the role of terrestrial vertebrate taphonomic process drivers in eastern North America during the Cretaceous. The report of crocodyliform bite marks on the ornithomimosaur tibia shaft in this manuscript reinforces the importance of the role of crocodyliforms in the modification of terrestrial vertebrate remains during the Cretaceous in North America. The preserved invertebrate traces add to the sparse record of the presence of barnacles and other marine invertebrates on dinosaur bone, and the evidence of shark feeding on the ornithomimosaur femur support the “bloat-and-float” model of terrestrial vertebrate fossil deposition in marine deposits from the Cretaceous of eastern North America.

Recurrence Intervals for Intraplate Earthquakes in Eastern North America from Paleoseismological Data

1988 ◽  
Vol 59 (4) ◽  
pp. 207-211 ◽  
Author(s):  
Pradeep Talwani ◽  
Keith Collinsworth
Keyword(s):  
North America ◽  
Lake Sediments ◽  
Eastern North America ◽  
Seismic Zone ◽  
Intraplate Earthquakes ◽  
Soft Sediments ◽  
Seismic Zones ◽  
Statistical Studies ◽  
Recurrence Intervals ◽  
New Madrid

Abstract In intraplate settings in eastern North America, paleoseismological studies have been used to obtain recurrence of earthquake at three locations. As causative faults are usually inaccessible at these locations the effects of paleoearthquakes have been studied. While calculating recurrence intervals we have tacitly assumed that the earthquakes at each locality repeatedly occurred on the same faults. Indicators of paleoearthquakes that were studied include deformed soft sediments due to seismically induced liquefaction (New Madrid and Charleston, SC, seismic zones), warped lake sediments and anomalous silt layers in otherwise organic rich sediments (Charlevoix, Canada seismic zone). The resulting recurrence intervals for New Madrid (≈ 600 years) and Charleston (1500–2000 years) are in general agreement with those obtained from statistical studies. At Charlevoix it was estimated that a MM intensity VI event (sufficient to disturb varves) occurs every ≈ 400 years.

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