Late Quaternary sea-level history and the antiquity of mammoths (\u3ci\u3eMammuthus exilis\u3c/i\u3e and \u3ci\u3eMammuthus columbi\u3c/i\u3e), Channel Islands National Park, California, USA

Fossils of Columbian mammoths (Mammuthus columbi) and pygmymammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ± 0.6 ka to 78.6 ± 0.5 ka, correlating the terrace withMIS 5.1, a time of relatively high sea level.Mammoths likely immigrated to the islands by swimming during the glacial periodsMIS 6 (~150 ka) orMIS 8 (~250 ka),when sea levelwas lowand the island–mainland distance was minimal, as during MIS 2. Earliest mammoth immigration to the islands likely occurred late enough in the Quaternary that uplift of the islands and the mainland decreased the swimming distance to a range that could be accomplished by mammoths. Results challenge the hypothesis that climate change, vegetation change, and decreased land area from sea-level rise were the causes of mammoth extinction at the Pleistocene/ Holocene boundary on the Channel Islands. Pre-MIS 2 mammoth populations would have experienced similar or even more dramatic changes at the MIS 6/5.5 transition

The San Antonio River Mammoth Site: Archaeological Testing Investigations for the Interstate 37 Bridge at the San Antonio River Improvement Project, Bexar County, Texas

On behalf of the Texas Department of Transportation (TxDOT), SWCA Environmental Consultants (SWCA) conducted test excavations on the San Antonio River Mammoth site (41BX1239) and 41BX1240 and surveys in the area of potential effects (APE) of the Interstate Highway (IH) 37 bridge project at the San Antonio River in southeastern Bexar County, Texas. Work was initiated to address the requirements of Section 106 of the National Historic Preservation Act (1966) as Amended and the Antiquities Code of Texas. The purpose of the investigations was to identify, delineate, and evaluate the significance of all archaeological and historic properties potentially affected by the undertaking and, if warranted, recommend the scope of additional work. Of particular concern, site 41BX1239 contains the remains of at least two mammoths with possible evidence of cultural association based on the initial investigations by Texas A&M in 1997. However, subsequent faunal analysis, conducted by Olga Potapova and Larry D. Agenbroad of the Mammoth Site in Hot Springs, North Dakota, found inconclusive evidence for definite or valid cultural modification to the specimens studied. The testing investigations on the San Antonio River Mammoth site included the re-exposure of the original Texas A&M 1997 site trench; limited hand-excavated units to further assess the prior interpretations of the deposits and recover a sample of bone; and a detailed geomorphological assessment. The work identified a bone bed consisting of the remains of at least two mammoths. Flotation of recovered sediments from these hand excavations identified flakes of siliceous material that are consistent with micro-debitage produced by the use and retouch of stone tools. Although at the highest thresholds of certainty, the cumulative evidence is likely yet insufficient to conclusively prove human interaction with the mammoth remains, the additional data gathered herein lend some credence to the prior interpretation of the site as archaeological rather than strictly paleontological. Concurring with the previous determination, the site is considered eligible for inclusion to the National Register of Historic Places (NRHP) and for listing as a State Archeological Landmark (SAL). However, the investigations determined the site deposits are located outside the APE of the current undertaking, and therefore the project will not affect deposits associated with the San Antonio River Mammoth site. The investigations of 41BX1240 identified only a very sparse scatter of primarily surficial materials in a heavily disturbed context with no associated features or diagnostic materials. Accordingly, the site is not recommended as eligible for listing on the NRHP or for designation as a SAL. The survey identified no new archaeological sites. Based on the avoidance of 41BX1239, it is SWCA’s recommendation that no archaeological properties will be affected by the IH 37 bridge rehabilitation

A Paleo-Indian Bison Kill In The Panhandle of Nebraska

Initial excavation of the Hudson-Meng Paleo-Indian site was begun in September, 1971. Work by volunteer labor continued until mid-November when the site was closed because of winter storms and frozen ground. The discovery of an unusually large Scottsbluff point, in situ in the ribs of one of the animals indicates association of the Plano Complex and extinct bison. The bone bed is a single occupation event. representing a butchering floor activity near the actual kill site. Absence of skull fragments and lower long bones indicate quartering or halving the animals at the kill with transfer to the butcher area. Testing in the field season of 1971 indicates a site at least 35 meters by 15 meters, with the limits of the bone bed yet to be determined

Clovis Projectile Point Occurrences In Northwestern Nebraska

Two 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

Excavation at the Hot Springs Mammoth Site: A Late Pleistocene Animal Trap

Construction work on a housing development in southern Hot Springs, South Dakota, during July 1974 exposed teeth, tusks, skulls, and post-cranial elements of mammoth. These were located in a small deposit of sand within the Spearfish Formation, a red shale of Permian-Triassic age. The deposit was originally a topographic depression. Prior to construction, it stood as a ridge, the sand and gravel armoring the adjacent shale. It is currently a sandy knob left by the construction work. Initial excavation during 1974 and 1975 (Agenbroad and Jones, 1975) was salvage and exploratory in nature. The abundant faunal remains from such efforts resulted in a field season from June 13 to July 19, 1976

The geology of the Atlas Mine area, Pima County, Arizona

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Cenozoic stratigraphy and paleo-hydrology of the Redington-San Manuel area, San Pedro Valley, Arizona

Post-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

Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska

Inordinate structural failure in several buildings on the Chadron State College campus has occurred in recent years. Disregard for hydrogeologic conditions and their effect on foundation material accounts for part of the damage

The Geology of the Atlas Mine Area, Pima County, Arizona

The 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]