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Displaying 31 - 33 from the 33 total records
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The Port Orford, Oregon, Meteorite Mystery
Roy S. Clarke, Jr., editor
43 pages, 19 figures, 7 tables
1993 (Date of Issue: 4 January 1993)
Number 31, Smithsonian Contributions to the Earth Sciences
DOI: 10.5479/si.00810274.31.1
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Abstract

The Port Orford meteorite was allegedly discovered by John Evans, a contract explorer for the United States Government, on a mountain in southwestern Oregon in 1856. Efforts to organize the recovery of the alleged 10-ton body for placement in the Smithsonian Institution in Washington, D.C., began in late 1859, but were abandoned as a consequence of the simultaneous onset of the Civil War and Evans' death.

Early in this century journalistic reports revived the story and stimulated numerous unsuccessful amateur meteorite hunting expeditions into the inaccessible Siskiyou National Forest. Smithsonian investigators visited the vaguely defined site without success in 1929 and 1939. As time passed, it became increasingly obvious to some involved officials that there was something wrong with the original accounts. Nevertheless, most persons persisted in their belief that Evans' story was true.

This monograph combines an historical study by Howard Plotkin ("John Evans and the Port Orford Meteorite Hoax," pages 1-24), and a technical study by V.F. Buchwald and Roy S. Clarke, Jr. ("A Mystery Solved: The Port Orford Meteorite is an Imilac Specimen," pages 25-43).

In the first paper, Plotkin details the history of the mysterious lost Port Orford meteorite, and presents previously unreported evidence that indicates Evans was ill-trained for his scientific field work, which was superfically and unprofessionally executed, and that he had amassed a staggering personal debt by consistently overspending his budget. Most startling of all, Plotkin's research led him to the inescapable conclusion that Evans had acquired a small but very rare piece of meteorite, and had hatched a clever scheme whereby he could use it to turn around his financial affairs. Plotkin reconstructs in detail how Evans planned to carry out this hoax.

Finally, Plotkin endeavors to establish the true identity of the meteoritic sample. On the basis of its overall physical appearance, degree of weathering, and chemical composition, Plotkin argues that the Port Orford specimen is a fragment of Imilac, a Chilean pallasite discovered in 1820-1822. He further contends that Evans acquired it from someone else while crossing the Isthmus of Panama on his final return trip from Oregon during the fall of 1858.

In the second paper, Buchwald and Clarke describe the involvement of the National Museum of Natural History in attempts during this century to recover the meteorite, and they report on their detailed technical studies of the Port Orford specimen and other possibly related meteorites.

Buchwald and Clarke point out that only three distinct pallasite falls were known in the late 1850s: (1) the single Krasnojarsk, Siberia, mass, (2) the two large masses of the Brahin, Belorussiya, meteorite, and (3) the Imilac, Chile, shower. Both Krasnojarsk and Brahin were ruled out of a possible hoax scenario on the basis of physical properties and state of corrosion, which left Imilac as the only possibility short of invoking an otherwise completely unknown fall. They therefore undertook detailed metallographic and mineralogical examinations of the Port Orford specimen and several Imilac specimens in an attempt to resolve the matter.

They find that the Port Orford specimen is a main group pallasite that is chemically, structurally, and morphologically indistinguishable from Imilac. The steep thermal gradient of its heat-altered zone shows it to be an individual from a shower-producing fall and that it could not have been a specimen removed from a large mass. Its weathering history suggests the arid conditions of the high desert of Chile, not the humid Oregon coast forests. Port Orford's kamacite composition and hardness, olivine composition, trace element levels in metal, and shock levels in kamacite and troilite are all within observed ranges for the Imilac shower or within reasonable extensions thereof. These many congruencies led Buchwald and Clarke to conclude that the Port Orford meteorite is an Imilac specimen, and that Evans perpetrated a deliberate hoax using a small Imilac individual as bait.


The Guadalupian Symposium
Bruce R. Wardlaw, Richard E. Grant and David M. Rohr, editors
415 pages, 191 figures, 43 plates, 45 tables
2000 (Date of Issue: 21 August 2000)
Number 32, Smithsonian Contributions to the Earth Sciences
DOI: 10.5479/si.00810274.32.1
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Abstract

The internal stratigraphy of the Cutoff Formation in the Guadalupe Mountains is clarified, and the unit is divided into three members: the Shumard Canyon, the El Centro, and the Williams Ranch members. The Shumard Canyon Member of the Cutoff Formation in the Guadalupe Mountains correlates to the upper part of the Cathedral Mountain Formation in the Glass Mountains. The El Centro and Williams Ranch members of the Cutoff Formation and the lower part of the Brushy Canyon Formation, including the Pipeline Shale in the Guadalupe Mountains, correlate to the Road Canyon Formation. The changeover in conodonts from transitional forms to Mesogondolella nankingensis) provides a basal definition for the Guadalupian and occurs within correlation unit 3 in the El Centro Member of the Cutoff Formation and cycle 2 of the Road Canyon Formation.

The geology, stratigraphy, and depositional setting of the Permian in the Del Norte Mountains and of the Word Formation in the Glass Mountains are discussed in detail, and this data suggest deposition in a foreland basin or backbay between the Marathon Fold Belt and the Delaware basin. The internal stratigraphy of the Road Canyon, Word, Vidrio, Altuda, Capitan, and Tessey formations reveal the following: (1) the Road Canyon was deposited in four cycles and the Word in six cycles; (2) the Altuda can be divided into five informal members and the Tessey into three members; (3) the Vidrio is an unconformity-bounded unit; and (4) the Capitan displays characteristic platform margin to slope foresets.

Biozonation of the Guadalupian is discussed, and details are provided on the fusulinid and conodont zonations. Changes in conodont fauna, based on the succession of Mesogondolella species from M. nankingensis to M. altudaensis, divide the Guadalupian into five zones.

Five new species of conodonts (Sweetina crofti Wardlaw, Mesogondolella shannoni Wardlaw, Hindeodus wordensis Wardlaw, Iranognathus punctatus Wardlaw, and Sweetognathus bicarinum Wardlaw) and two new species of fusulinids (Codonofusiella (Lantschichites) altudaensis Wilde and Rudine and Rauserella bengeensis Wilde and Rudine) are described.


Great Basin Aquatic Systems History
Robert Hershler, David Madsen, and Donald R. Currey, eds.
405 pages, 190 figures, 21 tables
2002 (Date of Issue: 11 December 2002)
Number 33, Smithsonian Contributions to the Earth Sciences
DOI: 10.5479/si.00810274.33.1
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Abstract
The 14 papers collected herein treat diverse aspects of the aquatic history of the Great Basin of the western United States and collectively attempt to summarize and integrate portions of the vast body of new information on this subject that has been acquired since the last such compilation was published in 1948. In the first section, four papers (Lowenstein, Negrini, Reheis et al., Sack) focus on the physical aspects of the Great Basin paleolake histories, whereas a fifth paper (Oviatt) summarizes the contributions to the study of Bonneville Basin lacustrine history made by two early giants of the field, Grove Karl Gilbert and Ernst Antevs. In the second section, four papers synthesize perspectives on Great Basin aquatic history provide by diatoms and ostracods (Bradbury and Forester), fishes (Smith et al.), aquatic insects (Polhemus and Polhemus), and aquatic snails (Hershler and Sada), whereas a fifth (Sada and Vinyard) summarizes the conservation status of the diverse aquatic biota that is endemic to the region. In the final section, three papers integrate terrestrial biotic evidence pertaining to Great Basin aquatic history derived from pollen from cores (Davis), floristics (Wigand and Rhode), and the mammal record (Grayson), whereas a fourth (Madsen) examines the relationship between Great Basin lakes and human inhabitants of the region. Although diverse in scope and topic, the papers in this volume are nonetheless linked by an appreciation that integration of geological, biological, and anthropological evidence is a necessary and fundamental key to a mature understanding of Great Basin aquatic systems history.

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