30 research outputs found

    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

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    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

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    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

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    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

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    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

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    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

    Hydrogeologic Relationships to Structural Failure Chadron State College, Nebraska

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    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

    Quaternary Studies : Glen Canyon National Recreation Area and Canyonlands National Park : Phase I Report

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