The Last 30,000 Years of Faunal History within the Grand Canyon, Arizona

1981 ◽  
Vol 15 (3) ◽  
pp. 311-326 ◽  
Author(s):  
Jim I. Mead
Keyword(s):  
Late Pleistocene ◽  
Grand Canyon ◽  
Late Glacial ◽  
Environmental Data ◽  
Desert Tortoise ◽  
Vertebrate Fauna ◽  
Mammalian Herbivores ◽  
Plant Fossil ◽  
Fossil Assemblages

AbstractThe vertebrate fauna of the last 30,000 radiocarbon years in the Grand Canyon is reviewed. Faunas accompanied with 92 14C dates have been analyzed from nine cave sites (four systematically excavated) and 50 packrat middens. Reasonably precise chronological and environmental data of late Pleistocene and Holocene age were obtained through dung studies in Rampart, Muav, and Stanton's Caves; from the numerous packrat middens; and from a ringtail refuse deposit in Vulture Cave. The desert tortoise, 8 species of lizards, 12 species of snakes, 68 species of birds, and 33 species of mammals are identified. Extinct animals include the avian carrion feeder, Teratornis merriami, and the mammalian herbivores, Oreamnos harringtoni, Camelops cf. hesternus, Equus sp., and Nothrotheriops shastense. There is no apparent abrupt end to the late Pleistocene as observed in the Grand Canyon fossil faunal or floral record. Animal and plant taxa of the Grand Canyon responded individually to the changes in climate of the last 30,000 yr. Both animal and plant fossil assemblages indicate that a pre-full glacial, a full glacial, and a late glacial woodland community with many less dominant desert taxa were slowly replaced by a Holocene desert community. All woodland taxa were absent from the lower elevations of the Grand Canyon by 8500 yr B.P.

Review of feeding ecology data of Late Pleistocene mammalian herbivores from South America and discussions on niche differentiation

2015 ◽  
Vol 140 ◽  
pp. 158-165 ◽  
Author(s):  
Lucas de Melo França ◽  
Lidiane de Asevedo ◽  
Mário André Trindade Dantas ◽  
Adriana Bocchiglieri ◽  
Leonardo dos Santos Avilla ◽  
...  
Keyword(s):  
South America ◽  
Late Pleistocene ◽  
Feeding Ecology ◽  
Niche Differentiation ◽  
Mammalian Herbivores

Plant Taphonomy in Fluvial and Lacustrine Systems

1986 ◽  
Vol 15 ◽  
pp. 10-26 ◽  
Author(s):  
Robert A. Spicer ◽  
Anthony G. Greer
Keyword(s):  
Pollen Grains ◽  
Plant Organs ◽  
Plant Fossil ◽  
Depositional System ◽  
Organ Type ◽  
Fossil Assemblages ◽  
Biased Samples

Plant fossil assemblages are biased samples of the capacity of the once living source vegetation to produce litter (leaves, flowers, pollen, spores, fruits, seeds, twigs, branches, trunks, roots etc.). The “image” that the depositional system “sees” of the vegetation is in terms of isolated plant organs (or parts of organs) that are produced in greater or lesser quantities depending on the organ type. For instance throughout the life of a tree hundreds of thousands of leaves, many millions of pollen grains but only one trunk are produced. Only very rarely do plant fossil assemblages consist of entire or nearly entire plants. Instead assemblages consist of a mixture of organs in various states of completeness derived from a number of different taxa (each of which produces different organs in different relative amounts) growing at various distances from the depositional site.

Progressive glacial retreat in the Southern Altiplano (Uturuncu volcano, 22°S) between 65 and 14 ka constrained by cosmogenic 3He dating

2014 ◽  
Vol 82 (1) ◽  
pp. 209-221 ◽  
Author(s):  
Pierre-Henri Blard ◽  
Jérôme Lave ◽  
Kenneth A. Farley ◽  
Victor Ramirez ◽  
Nestor Jimenez ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Late Glacial ◽  
Glacial Period ◽  
Tropical Andes ◽  
Equilibrium Line Altitude ◽  
Glacial Retreat ◽  
Late Glacial Period ◽  
Cold Episode ◽  
Glacial Landforms ◽  
Exposure Ages

AbstractThis work presents the first reconstruction of late Pleistocene glacier fluctuations on Uturuncu volcano, in the Southern Tropical Andes. Cosmogenic 3He dating of glacial landforms provides constraints on ancient glacier position between 65 and 14 ka. Despite important scatter in the exposure ages on the oldest moraines, probably resulting from pre-exposure, these 3He data constrain the timing of the moraine deposits and subsequent glacier recessions: the Uturuncu glacier may have reached its maximum extent much before the global LGM, maybe as early as 65 ka, with an equilibrium line altitude (ELA) at 5280 m. Then, the glacier remained close to its maximum position, with a main stillstand identified around 40 ka, and another one between 35 and 17 ka, followed by a limited recession at 17 ka. Then, another glacial stillstand is identified upstream during the late glacial period, probably between 16 and 14 ka, with an ELA standing at 5350 m. This stillstand is synchronous with the paleolake Tauca highstand. This result indicates that this regionally wet and cold episode, during the Heinrich 1 event, also impacted the Southern Altiplano. The ELA rose above 5450 m after 14 ka, synchronously with the Bolling–Allerod.

scholarly journals A basal aïstopod from the earliest Pennsylvanian of Canada, and the antiquity of the first limbless tetrapod lineage

2018 ◽  
Vol 5 (12) ◽  
pp. 181056 ◽  
Author(s):  
Jason D. Pardo ◽  
Arjan Mann
Keyword(s):  
Nova Scotia ◽  
New Genus ◽  
Taxonomic Diversity ◽  
Unique Representation ◽  
Vertebrate Fauna ◽  
Lower Jaw ◽  
Anterior Half ◽  
True Diversity ◽  
Fossil Assemblages

Earliest Pennsylvanian (Bashkirian) vertebrate fossil assemblages of the Joggins Formation (Cumberland Group) of Nova Scotia, Canada, have long been noted for the unique representation of the earliest known crown amniotes, but the overall vertebrate fauna remains poorly understood. The vast majority of Joggins vertebrates have historically been assigned to the Microsauria, a group originally established by Dawson specifically to accommodate the abundant, diminutive fossils of the Joggins Formation. As the Microsauria concept has evolved, some Joggins taxa (e.g. the eureptile Hylonomus lyelli ) have been removed from the group, but many of the Joggins ‘microsaurs’ remain unrevised, obscuring the true diversity of the earliest Pennsylvanian tetrapod fauna. Here we amend part of this problem by revisiting the morphology of Dawson's ‘microsaur’ Hylerpeton longidentatum . This taxon, represented by the anterior half of a left hemimandible, is here reinterpreted as a plesiomorphic aïstopod and assigned to a new genus, Andersonerpeton . A. longidentatum shows a surprisingly primitive anatomy of the lower jaw, retaining a parasymphyseal fang pair on the dentary, an adsymphyseal bone bearing a denticle field, fangs on all coronoids and parasymphyseal foramina, as well as a prearticular which extends far anterior along the coronoid series. However, several aïstopod characters can also be seen, including a lack of sculpturing on the dentary and a reduced number of recurved, weakly socketed teeth. The anatomy of A. longidentatum corroborates recent phylogenetic work which has placed the origin of aïstopods within the Devonian fin-to-limb transition but preserves a mosaic of characteristics suggesting an even earlier divergence. The presence of an aïstopod in the Joggins fauna expands the taxonomic diversity of the Joggins fauna and suggests that Joggins may preserve a more typical Carboniferous fauna than previously thought.

Changes in dominance patterns in upper Carboniferous plant-fossil assemblages

Geology ◽  
1982 ◽  
Vol 10 (12) ◽  
pp. 641 ◽  
Author(s):  
Hermann W. Pfefferkorn ◽  
Margaret C. Thomson
Keyword(s):  
Upper Carboniferous ◽  
Plant Fossil ◽  
Fossil Assemblages

Reliable Late-Pleistocene Stratigraphic Ages and Shorter Groundwater Travel Times from14C in Fossil Snails from the Southern Great Basin

1997 ◽  
Vol 47 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Robert Brennan ◽  
Jay Quade
Keyword(s):  
Great Basin ◽  
Late Pleistocene ◽  
Late Glacial ◽  
High Water ◽  
Land Snails ◽  
Nuclear Waste Repository ◽  
Travel Times ◽  
Terrestrial Snails ◽  
Geologic Record ◽  
High Level

Both aquatic and land snails are common in the geologic record, but their utility in dating is greatly restricted by their well-documented tendency to yield14C dates inconsistent with true14C ages. In this study, we examine the use of14C ages from (1) small, previously unstudied, terrestrial snails to date hosting spring deposits and from (2) cooccuring aquatic snails to constrain groundwater travel times during the last glacial period. Our study area in the southern Great Basin encompasses Yucca Mountain, site of the proposed high-level nuclear waste repository, where information on the age and extent of past high water tables and on groundwater flow times is crucial to several licensing issues. Our results show that shells of small terrestrial snails belonging toValloniasp. yield14C dates consistent with14C ages of associated carbonized wood. These results imply that these taxa can provide reliable14C age control on the broadly distributed deposits in which they have been described. In contrast, cooccurring aquatic snails from fossil spring deposits yield14C ages generally greater than the control age. This is because the aquatic shells often formed in spring waters that had an initial14C deficiency. However, the magnitude of the deficiency is much less than that observed in nearby modern springs, arguing for much higher average14C contents in late Pleistocene groundwaters in these basins. If representative, this implies shorter groundwater travel times through aquifers in southern Nevada during late-glacial time.

Late Pleistocene Palaeohydrology of the Moksha River (the Volga Basin)

2020 ◽  
Author(s):  
Ekaterina Matlakhova ◽  
Andrei Panin ◽  
Vadim Ukraintsev
Keyword(s):  
Late Pleistocene ◽  
River Runoff ◽  
Late Glacial ◽  
River Valley ◽  
East European Plain ◽  
Russian Science ◽  
East European ◽  
Meandering Channel ◽  
High Flood ◽  
High Runoff

<p>The Moksha River valley was studied in its lower part between the Tsna River confluence and the mouth of the Moksha River. Wide floodplain and two levels of terraces are presented on the studied part of the valley. The height of the floodplain is from 1 to 6 m, of the first terrace – about 9-11 m, of the second terrace – 18-22 m. The width of the valley in this area is about 14-16 km, but sometimes it can reach 20-22 km and more. The width of the floodplain is about 12-14 km.</p><p>The Moksha River is a meandering channel. Large and small (modern-size) meandering palaeochannels spread widely on the floodplain surface. These palaeochannels were the main objects of our study. Small palaeochannels have the same parameters as the modern river channel: their width is about 100-150 m, wavelength is between 300-400 and 600-700 m. For the large palaeochannels (macromeanders) the mean parameters are the following: width is about 250-300 m, wavelength is about 1500-2000 m. These large palaeochannels are the signs of high flood activity epoch(s).</p><p>In our study we used a number of field and laboratory methods. Twelve boreholes in large and small palaeochannels were made during fieldwork in August-September 2019. Organic material from studied palaeochennels was sampled to make radiocarbon (AMS) dating to find the time of palaeochannels’ formation and infilling. Also we made the reconstructions of paleo-discharges of the Moksha River based on paleochannels’ parameters.</p><p>We studied both large and small palaeochannels to reconstruct palaeohydrology and history of the Moksha River valley development in Late Pleistocene. Large palaeochannels correspond to the time of high river runoff. The oldest ones of small palaeochannels were studied to know the time of lowering of the river runoff. Presumably, large palaeochannels were formed at the end of Late Glacial (after LGM) when river runoff was much higher than the modern one. This period of extremely high runoff was previously distinguished in many river valleys of East European Plain, where formation of large paleochannels is usually associated with Late Glacial (the end of MIS 2). Lowering of runoff on the central part of the East European Plain is usually associated with the beginning of the Holocene.</p><p>This study is supported by Russian Science Foundation (Project № 19-17-00215).</p>

Late Pleistocene Settlement in the Nenana Valley, Central Alaska

1989 ◽  
Vol 54 (2) ◽  
pp. 263-287 ◽  
Author(s):  
William R. Powers ◽  
John F. Hoffecker
Keyword(s):  
Late Pleistocene ◽  
Late Glacial ◽  
Alaska Range ◽  
Ongoing Research ◽  
Large Mammal ◽  
Seasonal Basis

Ongoing research in the Nenana Valley is uncovering a complex record of Late Glacial settlement in the foothills of the Alaska Range. A local eolian sequence provides relatively precise stratigraphic and chronological control, permitting integration with regional paleoclimatic history. Initial occupation seems to have occurred approximately 12,000 years ago, and is represented by several assemblages containing bifacial points. Microblade technology did not appear until ca. 10,500 B.P. The valley probably was exploited on a seasonal basis for large mammal procurement.

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