31 research outputs found
World of Elephants 2: Selected papers from the 2nd Congress, Mammoth Site of Hot Springs
No full text[No abstract available
The early Middle Pleistocene mammalian fauna from Pagliare di Sassa (l'Aquila, central Italy): new data
No full textAgenbroad L.D., Symington. R. L. (eds)Mammoth Site Scientific Papers
Clovis Projectile Point Occurrences In Northwestern Nebraska
Get PDFTwo Clovis projectile point finds are reported from the Panhandle of Nebraska (Dawes and Sioux Counties). Both are surface finds and both bear resemblance to finds in Arizona and Oklahoma.
Two recent Clovis projectile point finds from the Panhandle of Nebraska warrent description. The artifacts are in the possession discoverer, Mr. William (Bill) Hudson of Crawford, Nebraska. Both artifacts are surface finds in local areas of bad land topography in Dawes and Sioux Counties. The rarity of Occurrence of this distinctive projectile point in Nebraska, whether surface find or not, makes the discoveries of importance. To my knowledge (Agenbroad, 1971), there are no occurrences of Clovis projectile points, in situ, in stratified sites within the state. At least all published records are a surface finds or recovered from sand screening operations in gravel pits. The significance of Clovis projectile points as time and cultural markers makes record of their occurrence important regardless of the nature of the find.
The two Panhandle points include one complete point and one basal fragment (Fig. 1). The metric data (in mm unless stated otherwise) for the two points are as follows: data for the complete point are given first, that for the basal fragment follow in parentheses: maximum width 29(33), weight in grams 37.6 (-), maximum thickness 9 (5), maximum length 106 (-), distance from base to point of maximum thickness 53 (41), base width 26 (31), depth of basal concavity 5 (6), flute scar 0.30, R. 29 (0.22, R.37), lateral grind L(29) R37, L31, R(39). Both points are of agate.
Comparison of the metric data for these specimens and that for points recovered at classic sites (e.g., Lehncr Ranch, Naco I and II, Murray Springs, Escapule. Arizona; Dent, Colorado; Clovis, New Mexico; and Domebo. Oklahoma) indicate that the Nebraska points readily fall within the range of values for points from classic sites. The greatest affinities of the Nebraska points are with those of the Arizona and Oklahoma sites
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The Geology of the Atlas Mine Area, Pima County, Arizona
No full textThe Atlas Mine is located on the northwest flank of the Silver Bell mountains; Silver Bell mining district, Pima County, Arizona. The deposit is high grade (?) sine-copper mineralization in an altered sedimentary sequence. Rocks in the area include Precambrian (?) alaskite; Permian (?) limestone, quartzite and siltstone; Tertiary (?) monzonite, quartz monzonite, quarts latite porphyry and dacite porphyry; and Quaternary alluvium. The limestone has been largely metamorphosed to a mass of tactite, siltstone has been locally metamorphosed to hornfels, and the quartzite has been silicified, locally shattered and altered. Mineralization is related to NE and E-W trending fault systems, and similarly trending intrusive dikes. Predominate ore minerals are sphalerite and chalcopyrite, associated with pyrite, specular hematite and “high temperature" silicates. Copper mineralization is related to the silicified sediments. Zinc mineralization is present in silicates but is more predominate in areas of recrystallized calcite and extensive garnetization, suggesting incomplete replacement of the original sediments by the silicates. Further exploration and development should be undertaken in areas of favorable structural control, and adjacent to favored intrusives.Antevs LibraryThis item is part of the Geosciences Theses collection. It was digitized from a physical copy provided by the Antevs Library, Department of Geosciences, University of Arizona. For more information about items in this collection, please email the Antevs Library, [email protected]
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Cenozoic stratigraphy and paleo-hydrology of the Redington-San Manuel area, San Pedro Valley, Arizona
No full textPost-Miocene fluvial and lacustrine units coristitute the valley fill of the San Pedro Valley, near Redington, Arizona. These sediments are relatively flat lying units deposited on older, deformed sediments, fault blocks of Tertiary volcanics, and erosion surfaces on Precambrian crystalline rocks. The sedimentary sequence is composed of silts, inudstone, sands, gravels, limestone, gypsum, diatomite, and pyroclastic units. Previous investigations have designated these lithologies one unit, the Gila Conglomerate. A recent study in the Mammoth area (Heindi, 1963) subdivided the Gila Conglomerate into the Quiburis formation, Sacaton formation and Pleistocene to Recent alluvial deposits. In the present study, this nomenclature was utilized, with a proposed subdivision of the Quiburis formation. Detailed mapping of the lithologic units indicate a lateral facies change within the Quiburis formation0 The conglomeritic member of the Quiburis formation interfingers with a central, fine-grained member, and the names Tres Alasnos, and Redington are proposed for these units. The age of the Quiburis formation is based on its stratigraphic position, and vertebrate fossils. The Qulbuns ovenlies tilted sediments containing Miocene fauna, and its upper portions contain fauna which have been assigned a middle to late Pliocene Age. The Sacaton formation was deposited on an erosion surface in the Quiburis in late Pliobene to early Pleistocene time; it was then entrenched and local, middle to late Pleistocene lacustnine units were deposited in the drainage pattern. Fresh water mollusks, horse and mammoth remains are present in the lacusbnine units. The Pleistocene lacustrine units were truncated by late Pleistocene terraces, and degradation proceeded to approximately 80 feet below the present floodplain. Aggradation occurred, to a level above the present floodplain, as attested by prehistoric hearths buried in river sediments, above the present stream gradient. Since 1880 the San Pedro River has begun another period of downcutting. The sedimentary deposits control the movement of ground water in the valley. Two hydrologic systems are present; a shallow water table system in the floodplain and river channel area, and an artesian system at 630- 1,200 feet below the valley floor in the northern portion of the study area. It is believed that deformed, pre- Miocene sedinentary units provide the source of recharge to the artesian system. Detailed mapping of the sedimentary units reveals a meandering central trough of the ancestoral San Pedro River. The contact between the Redington and Tres Alamos members of the Quiburis formation indicate the meander pattern, and its control by bedrock outcrop. Structural activity continued through Pliocene time, and is represented by north trending normal faults. Minor slump structures and small reverse faults are present in the Redington member of the Quiburis formation. A site survey, carried out during the field mapping, resulted in the location of nineteen archaeological sites. The sites range from preceramic Desert Culture to Salado and probably to later cultures such as the Apache. Older sites are peripheral to the valley axis, with more recent sites concentrated along the river. It appears that geologic-hydrologic factors controlling site location are: water sources; agricultural or gathering areas; quarry, or source material sites; and vantage points.hydrology collectio
Radiocarbon Chronologies and Extinction Dynamics of the Late Quaternary Mammalian Megafauna of the Taimyr Peninsula, Russian Federation
Get PDFThis paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox (Ovibos moschatus), moose (Alces alces), reindeer (Rangifer tarandus), horse (Equus caballus) and wolf (Canis lupus). New evidence permits reanalysis of megafaunal extinction dynamics in the Asian high Arctic periphery. Increasingly, radiometric records of individual species show evidence of a gap at or near the Pleistocene/Holocene boundary (PHB). In the past, the PHB gap was regarded as significant only when actually terminal, i.e., when it marked the apparent ‘‘last’’ occurrence of a species (e.g., current ‘‘last’’ occurrence date for woolly mammoth in mainland Eurasia is 9600 yr BP). However, for high Arctic populations of horses and muskoxen the gap marks an interruption rather than extinction, because their radiocarbon records resume, nearly simultaneously, much later in the Holocene. Taphonomic effects, ΔC14 flux, and biased sampling are unlikely explanations for these hiatuses. A possible explanation is that the gap is the signature of an event, of unknown nature, that prompted the nearly simultaneous crash of many megafaunal populations in the high Arctic and possibly elsewhere in Eurasia.
