Supplemental material: Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

2006 ◽  
Author(s):  
J.K. Madsen ◽  
D.J. Thorkelson ◽  
R.M. Friedman ◽  
D.D. Marshall
Keyword(s):  
North America ◽  
Pacific Basin ◽  
Western North America ◽  
File Size ◽  
Tectonic Model ◽  
Ridge Subduction ◽  
The Pacific ◽  
Northwestern North America ◽  
Slab Window

Geosphere, February 2006, v. 2, p. 11-34, doi: 10.1130/GES00020.1. Movie 1 - Tectonic model for the Pacific Basin and northwestern North America from 53 Ma to 39 Ma. The file size is 1.3 MB.

scholarly journals Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

Geosphere ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 11 ◽  
Author(s):  
J.K. Madsen ◽  
D.J. Thorkelson ◽  
R.M. Friedman ◽  
D.D. Marshall
Keyword(s):  
North America ◽  
Pacific Basin ◽  
Western North America ◽  
Ridge Subduction ◽  
The Pacific ◽  
Slab Window

A new genus of cassiduloid echinoid from the lower Eocene of the Pacific coast of western North America and a new report of Cassidulus ellipticus Kew, 1920, from the lower Eocene of Baja California Sur, Mexico

1995 ◽  
Vol 69 (3) ◽  
pp. 509-515 ◽  
Author(s):  
Richard L. Squires ◽  
Robert A. Demetrion
Keyword(s):  
North America ◽  
New Genus ◽  
Baja California ◽  
Pacific Coast ◽  
Middle Part ◽  
Baja California Sur ◽  
Western North America ◽  
Lower Eocene ◽  
Shallow Marine ◽  
The Pacific

The cassiduloid echinoid Calilampas californiensis n. gen. and sp. is described from middle lower Eocene (“Capay Stage”) shallow-marine sandstones in both the middle part of the Bateque Formation, Baja California Sur, Mexico, and the lower part of the Llajas Formation, southern California. The new genus is tentatively placed in family Pliolampadidae. The cassiduloid Cassidulus ellipticus Kew, 1920, previously known only from the “Capay Stage” in California, is also present in “Capay Stage” shallow-marine sandstones of the Bateque Formation.

The Inland Penetration of Atmospheric Rivers over Western North America: A Lagrangian Analysis

2015 ◽  
Vol 143 (5) ◽  
pp. 1924-1944 ◽  
Author(s):  
Jonathan J. Rutz ◽  
W. James Steenburgh ◽  
F. Martin Ralph
Keyword(s):  
Water Vapor ◽  
North America ◽  
Pacific Coast ◽  
Water Vapor Transport ◽  
Western North America ◽  
Lagrangian Analysis ◽  
Initial Water ◽  
Atmospheric Rivers ◽  
The Pacific ◽  
Synoptic Conditions

Abstract Although atmospheric rivers (ARs) typically weaken following landfall, those that penetrate inland can contribute to heavy precipitation and high-impact weather within the interior of western North America. In this paper, the authors examine the evolution of ARs over western North America using trajectories released at 950 and 700 hPa within cool-season ARs along the Pacific coast. These trajectories are classified as coastal decaying, inland penetrating, or interior penetrating based on whether they remain within an AR upon reaching selected transects over western North America. Interior-penetrating AR trajectories most frequently make landfall along the Oregon coast, but the greatest fraction of landfalling AR trajectories that eventually penetrate into the interior within an AR is found along the Baja Peninsula. In contrast, interior-penetrating AR trajectories rarely traverse the southern “high” Sierra. At landfall, interior-penetrating AR trajectories are associated with a more amplified flow pattern, more southwesterly (vs westerly) flow along the Pacific coast, and larger water vapor transport (qυ). The larger initial qυ of interior-penetrating AR trajectories is due primarily to larger initial water vapor q and wind speed υ for those initiated at 950 and 700 hPa, respectively. Inland- and interior-penetrating AR trajectories maintain large qυ over the interior partially due to increases in υ that offset decreases in q, particularly in the vicinity of topographical barriers. Therefore, synoptic conditions and trajectory pathways favoring larger initial qυ at the coast, limited water vapor depletion by orographic precipitation, and increases in υ over the interior are keys to differentiating interior-penetrating from coastal-decaying ARs.

scholarly journals Glacier retreat creating new Pacific salmon habitat in western North America

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kara J. Pitman ◽  
Jonathan W. Moore ◽  
Matthias Huss ◽  
Matthew R. Sloat ◽  
Diane C. Whited ◽  
...  
Keyword(s):  
North America ◽  
Climate Models ◽  
Pacific Salmon ◽  
Global Climate ◽  
Global Climate Models ◽  
Glacier Retreat ◽  
Western North America ◽  
Mountain Ranges ◽  
Proactive Management ◽  
The Pacific

AbstractGlacier retreat poses risks and benefits for species of cultural and economic importance. One example is Pacific salmon (Oncorhynchus spp.), supporting subsistence harvests, and commercial and recreational fisheries worth billions of dollars annually. Although decreases in summer streamflow and warming freshwater is reducing salmon habitat quality in parts of their range, glacier retreat is creating new streams and lakes that salmon can colonize. However, potential gains in future salmon habitat associated with glacier loss have yet to be quantified across the range of Pacific salmon. Here we project future gains in Pacific salmon freshwater habitat by linking a model of glacier mass change for 315 glaciers, forced by five different Global Climate Models, with a simple model of salmon stream habitat potential throughout the Pacific Mountain ranges of western North America. We project that by the year 2100 glacier retreat will create 6,146 (±1,619) km of new streams accessible for colonization by Pacific salmon, of which 1,930 (±569) km have the potential to be used for spawning and juvenile rearing, representing 0 to 27% gains within the 18 sub-regions we studied. These findings can inform proactive management and conservation of Pacific salmon in this era of rapid climate change.

scholarly journals Using oxygen and hydrogen stable isotopes to track the migratory movement of Sharp-shinned Hawks (Accipiter striatus) along Western Flyways of North America

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0226318
Author(s):  
Elizabeth A. Wommack ◽  
Lisa C. Marrack ◽  
Stefania Mambelli ◽  
Joshua M. Hull ◽  
Todd E. Dawson
Keyword(s):  
Stable Isotope ◽  
North America ◽  
Large Scale ◽  
Pacific Coast ◽  
Isotope Analysis ◽  
Western North America ◽  
Migration Routes ◽  
The Pacific ◽  
Accipiter Striatus ◽  
Hydrogen And Oxygen Isotope

The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins than those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.

scholarly journals Raising the Resurrection plate from an unfolded-slab plate tectonic reconstruction of northwestern North America since early Cenozoic time

2020 ◽  
Author(s):  
Spencer Fuston ◽  
Jonny Wu
Keyword(s):  
North America ◽  
Three Dimensions ◽  
Aleutian Islands ◽  
Plate Tectonic ◽  
Plate Model ◽  
Ridge Subduction ◽  
Ocean Ridges ◽  
Tectonic Reconstruction ◽  
Northwestern North America ◽  
Early Cenozoic

The configuration of mid-ocean ridges subducted below North America prior to Oligocene time is unconstrained by seafloor isochrons and has been primarily inferred from upper-plate geology, including near-trench magmatism. However, many tectonic models are permitted from these constraints. We present a fully kinematic, plate tectonic reconstruction of the NW Cordillera since 60 Ma built by structurally unfolding subducted slabs, imaged by mantle tomography, back to Earth’s surface. We map in three-dimensions the attached Alaska and Cascadia slabs, and a detached slab below western Yukon (Canada) at 400−600 km depth that we call the “Yukon Slab.” Our restoration of these lower plates within a global plate model indicates the Alaska slab accounts for Pacific-Kula subduction since ca. 60 Ma below the Aleutian Islands whereas the Cascadia slab accounts for Farallon subduction since at least ca. 75 Ma below southern California, USA. However, intermediate areas show two reconstruction gaps that persist until 40 Ma. We show that these reconstruction gaps correlate spatiotemporally to published NW Cordillera near-trench magmatism, even considering possible terrane translation. We attribute these gaps to thermal erosion related to ridge subduction and model mid-ocean ridges within these reconstruction gap mid-points. Our reconstructions show two coeval ridge-trench intersections that bound an additional “Resurrection”-like plate along the NW Cordillera prior to 40 Ma. In this model, the Yukon slab represents a thermally eroded remnant of the Resurrection plate. Our reconstructions support a “northern option” Farallon ridge geometry and allow up to ∼1200 km Chugach terrane translation since Paleocene time, providing a new “tomographic piercing point” for the Baja-British Columbia debate.

scholarly journals A Quantitative Tomotectonic Plate Reconstruction of Western North America and the Eastern Pacific Basin

2020 ◽  
Vol 21 (8) ◽  
Author(s):  
Edward J. Clennett ◽  
Karin Sigloch ◽  
Mitchell G. Mihalynuk ◽  
Maria Seton ◽  
Martha A. Henderson ◽  
...  
Keyword(s):  
North America ◽  
Eastern Pacific ◽  
Pacific Basin ◽  
Western North America ◽  
Plate Reconstruction

scholarly journals North American Winter Dipole: Observed and Simulated Changes in Circulations

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 793 ◽  
Author(s):  
Yu-Tang Chien ◽  
S.-Y. Simon Wang ◽  
Yoshimitsu Chikamoto ◽  
Steve L. Voelker ◽  
Jonathan D. D. Meyer ◽  
...  
Keyword(s):  
North America ◽  
North American ◽  
Large Scale ◽  
Climate Model ◽  
Model Simulations ◽  
The North ◽  
Weather Events ◽  
The Pacific ◽  
Climate Model Simulations ◽  
Northwestern North America

In recent years, a pair of large-scale circulation patterns consisting of an anomalous ridge over northwestern North America and trough over northeastern North America was found to accompany extreme winter weather events such as the 2013–2015 California drought and eastern U.S. cold outbreaks. Referred to as the North American winter dipole (NAWD), previous studies have found both a marked natural variability and a warming-induced amplification trend in the NAWD. In this study, we utilized multiple global reanalysis datasets and existing climate model simulations to examine the variability of the winter planetary wave patterns over North America and to better understand how it is likely to change in the future. We compared between pre- and post-1980 periods to identify changes to the circulation variations based on empirical analysis. It was found that the leading pattern of the winter planetary waves has changed, from the Pacific–North America (PNA) mode to a spatially shifted mode such as NAWD. Further, the potential influence of global warming on NAWD was examined using multiple climate model simulations.

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