Morphological and genetic analyses identify a new record of a glacial relict: pygmy whitefish (Prosopium coulterii) from northwestern Ontario

2014 ◽  
Vol 92 (3) ◽  
pp. 267-271 ◽  
Author(s):  
P.J. Blanchfield ◽  
E.B. Taylor ◽  
D.A. Watkinson

The pygmy whitefish (Prosopium coulterii (Eigenmann and Eigenmann, 1892)) is a glacial relict species with a disjunct North American distribution that, apart from its most easterly known location in Lake Superior, is predominantly found in northern and western regions of Canada. Here we report on a new finding of pygmy whitefish from Winnange Lake in northwestern Ontario that extends the range of this species ∼320 km from its most easterly distribution in Lake Superior and almost 1500 km east of the closest previously known western localities. Genetic analyses confirmed that the fish from Winnange Lake were most closely related to the lineage that includes fish from Lake Superior and likely also originated via postglacial dispersal from a refugium in the upper Mississippi – Missouri river system.

Tectonics ◽  
1989 ◽  
Vol 8 (2) ◽  
pp. 305-332 ◽  
Author(s):  
W. F. Cannon ◽  
Alan G. Green ◽  
D. R. Hutchinson ◽  
Myung Lee ◽  
Bernd Milkereit ◽  
...  

Crustaceana ◽  
1993 ◽  
Vol 65 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Krzysztof Jaźdźewski ◽  
Alicja Konopacka

AbstractThe paper presents a survey of Polish malacostracan fauna. In two tables the distribution of freshwater and Baltic species is presented according to the regionalization of the country used in "Catalogus Faunae Poloniae". Figures present some interesting distributions of freshwater malacostracan taxa. Own studies as well as the review of ample literature aimed at the preparation of the successive issues of "Catalogus Faunae Poloniae" allowed to present this survey of 121 malacostracan taxa, viz., Bathynellacea - 1 species, Mysidacea - 9, Amphipoda - 50, Isopoda - 47, Tanaidacea - 1, Cumacea - 1, Euphausiacea - 1, Decapoda - 11. In inland waters 31 species and subspecies do occur (Batynellacea - 1, Mysidacea - 1, Amphipoda - 22, Isopoda - 2, Decapoda - 5). In brackish waters of the Baltic Sea and its lagoons- 54 species (Mysidacea - 8, Amphipoda - 24, Isopoda - 12, Tanaidacea - 1, Cumacea - 1, Euphausiacea - 1, Decapoda - 8). Bi-environmental species are Asellus aquaticus and Eriocheir sinensis. The land malacostracan fauna of Poland includes 4 amphipod and 34 isopod (oniscoid) taxa. The Polish malacostracan fauna is composed mainly of species that have invaded this region of Europe in the postglacial period, but the oldest, preglacial elements are subterranean amphipods (niphargids, Crangonyx) and Bathynella natans, occurring only in southern Poland. The earliest postglacial invaders of the Baltic and/or the northern lakes were glacial relict species like the Mysis relicta group, Pallasiola quadrispinosa, Monoporeia affinis and Saduria entomon. The Southern Baltic malacostracan fauna is dominated by Boreal and Arctic/(Subarctic)-boreal elements but one third of this fauna is Mediterranean-boreal or Lusitanian-boreal in origin. Inland waters were probably settled next by Gammarus lacustris, G. pulex, Synurella ambulans, Asellus aquaticus and Astacus astacus, then by later incomers, like Gammarus balcanicus. Canal constructions in the XVIIIth century helped the immigration of Ponto-Caspian elements: Corophium curvispinum and Echinogammarus ischnus. Intentionally introduced to Polish waters are Astacus leptodactylus, Orconectes limosus and Pacifastacus leniusculus; unintentionally brought along were Eriocheir sinensis and Rhithropanopeus harrisii tridentatus, as well as Talitroides alluaudi and Trichorhina tomentosa to some greenhouses.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
David B. Kemp ◽  
Peter M. Sadler ◽  
Veerle Vanacker

AbstractHumans are primary agents of geomorphic change, and rates of anthropogenic landscape change likely far exceed the pace of change expected from natural geologic processes. Nevertheless, our understanding of the impact of humans on the natural landscape is limited by difficulties in accurately comparing past and present rates of change across wide spatial and temporal scales. Here, we present a compilation of  >4000 rates of alluvial sediment accumulation that provide an indirect record of North American erosion, mass transfer and sediment storage from the late Pleistocene to the present day. Continent-wide rates of alluvium accumulation were broadly stable for ~40,000 years, but increased 10-fold during the rapid expansion of agriculture and river system modification associated with European colonization. Interpreted in terms of mass transfer, humans have moved as much sediment in North America in the past century as natural processes can transfer in 700–3000 years.


2020 ◽  
Vol 90 (9) ◽  
pp. 1175-1197
Author(s):  
Anne C. Fetrow ◽  
Kathryn E. Snell ◽  
Russell V. Di Fiori ◽  
Sean P. Long ◽  
Joshua W. Bonde

ABSTRACT Terrestrial sedimentary archives record critical information about environment and climate of the past, as well as provide insights into the style, timing, and magnitude of structural deformation in a region. The Cretaceous Newark Canyon Formation, located in central Nevada, USA, was deposited in the hinterland of the Sevier fold–thrust belt during the North American Cordilleran orogeny. While previous research has focused on the coarser-grained, fluvial components of the Newark Canyon Formation, the carbonate and finer-grained facies of this formation remain comparatively understudied. A more complete understanding of the Newark Canyon Formation provides insights into Cretaceous syndeformational deposition in the Central Nevada thrust belt, serves as a useful case study for deconvolving the influence of tectonic and climatic forces on sedimentation in both the North American Cordillera and other contractional orogens, and will provide a critical foundation upon which to build future paleoclimate and paleoaltimetry studies. We combine facies descriptions, stratigraphic measurements, and optical and cathodoluminescence petrography to develop a comprehensive depositional model for the Newark Canyon Formation. We identify six distinct facies that show that the Newark Canyon Formation evolved through four stages of deposition: 1) an anastomosing river system with palustrine interchannel areas, 2) a braided river system, 3) a balance-filled, carbonate-bearing lacustrine system, and 4) a second braided river system. Although climate undoubtedly played a role, we suggest that the deposition and coeval deformation of the synorogenic Newark Canyon Formation was in direct response to the construction of east-vergent contractional structures proximal to the type section. Comparison to other contemporary terrestrial sedimentary basins deposited in a variety of tectonic settings provides helpful insights into the influences of regional tectonics, regional and global climate, catchment characteristics, underlying lithologies, and subcrop geology in the preserved sedimentary record.


2011 ◽  
Vol 47 (3) ◽  
Author(s):  
L. Mari ◽  
E. Bertuzzo ◽  
R. Casagrandi ◽  
M. Gatto ◽  
S. A. Levin ◽  
...  

1997 ◽  
Vol 34 (4) ◽  
pp. 476-488 ◽  
Author(s):  
D. W. Davis ◽  
J. C. Green

Volcanism in the Midcontinent rift system lasted between 1108 and 1086 Ma. Rates of flood-basalt eruption and subsidence in the western Lake Superior region appear to have been greatest at the beginning of recorded activity (estimated 5 km/Ma subsidence rate at 1108 Ma) and rapidly waned over a period of 1–3 Ma during a magnetically reversed period. The age of the paleomagnetic polarity reversal is now constrained to be between 1105 ± 2 and 1102 ± 2 Ma. A resurgence of intense volcanism began at 1100 ± 2 Ma in the North Shore Volcanic Group and lasted until 1097 ± 2 Ma. This group contains a ca. 7 Ma time gap between magnetically reversed and normal volcanic sequences. A similar disconformity appears to exist in the upper part of the Powder Mill Group. The average subsidence rate during this period was approximately 3.7 km/Ma. Latitude variations measured from paleomagnetism on dated sequences indicate that the North American plate was drifting at a minimum rate of 22 cm/year during the early history of the Midcontinent rift. An abrupt slowdown to approximately 8 cm/year occurred at ca. 1095 Ma. These data support a mantle-plume origin for Midcontinent rift volcanism, with the plume head attached to and drifting with the continental lithosphere. Resurgence of flood-basalt magmatism at 1100 Ma may have been caused by extension of the superheated lithosphere following continental collision within the Grenville Orogen to the east.


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