Inaug.-diss.--Basel. / Curriculum vitae: p. [207]. "Separatabdruck aus Eclogae geologicae Helvetiae, bd. XVIII, hft. 1." Literaturverzeichnis: p. 205-206.

Inaug.-diss.--Erlangen. / Lebenslauf.

Proefschrift--Utrecht, 1946. / "Stellingen" ([2] p.) inserted. 1 folded map in pocket. Includes bibliographical references (p. [113]-115).

Inaug.-diss.--Berlin. / Vita. "Litteratur": p. 2-3.

Proefschrift--Amsterdam. / "Stellingen": 2 l. inserted. "Literature": p. [241]-244.

<p> The St. Cyr klippe hosts well preserved to variably retrogressed eclogites found as sub-meter to hundreds of meter scale lenses within quartzofeldspathic schists in the Yukon-Tanana terrane, Canadian Cordillera. The St. Cyr area consists of structurally imbricated, polydeformed, and polymetamorphosed units of continental arc and oceanic crust. The eclogite-bearing quartzofeldspathic schists form a 30 by 6 kilometer thick, northwest-striking, coherent package. The schists consist of metasediments and felsic intrusives that are intercalated on the tens of meter scale. The presence of phengite and Permian age zircon crystallized under eclogite facies metamorphic conditions indicates that the eclogite was metamorphosed <i>in situ</i> with its quartzofeldspathic host. </p><p> I investigated the metamorphic evolution of the eclogite-facies rocks in the St. Cyr klippe using isochemical phase equilibrium thermodynamic (pseudosection) modeling. I constructed <i>P-T</i> pseudosections in the system Na₂O-K₂O-CaO-FeO-O₂-MnO-MgO-Al₂O₃-SiO₂-TiO₂-H₂O for the bulk-rock composition of an eclogite and a host metatonalite. In combination with petrology and mineral compositions, St. Cyr eclogites followed a five-stage clockwise <i> P-T</i> path. Peak pressure conditions for the eclogites and metatonalites reached up to 3.2 GPa, well within the coesite stability field, indicating the eclogites reached ultrahigh-pressure conditions. Decompression during exhumation occurred with a corresponding temperature increase. </p><p> SHRIMP-RG zircon dating shows that the protolith of the eclogites formed within the Yukon-Tanana terrane during early, continental arc activity, between 364 and 380 Ma, while the metatonalite protolith formed at approximately 334 Ma, during the Little Salmon Cycle of the Klinkit phase of Yukon-Tanana arc activity. Both the eclogites and the metatonalites were then subducted to mantle depths and metamorphosed to ultrahigh-pressure conditions during the late Permian, between 266 and 271 Ma. The results of our study suggest portions of the Yukon-Tanana terrane were subducted to high-pressure and ultrahigh-pressure conditions. This is the first report of ultrahigh-pressure metamorphism in the accreted terranes of the North American Cordillera. Petrological, geochemical, geochronological, and structural relationships link the eclogites at St. Cyr to other eclogite localities in Yukon, indicating the high-pressure assemblages form a larger lithotectonic unit within the Yukon-Tanana terrane.</p>

Inaug.-diss. (PII. D.)--Universität Basel. / "Curriculum vitae" at end. "Separatbdruck aus 'Schweizerische mineralogische und petrographische mitteilungen' band VIII, heft 1, 1928."

Thesis (M.S.)--Ohio State University, 1955. / Available online via OhioLINK's ETD Center

<p> The study of terrestrial meteorite impact craters and of impacted meteorites expands our understanding of cratered rocky surfaces throughout the solar system. Terrestrial craters uniquely expand upon data from remote imaging and planetary surface exploration by providing analogs for understanding the buried sub-surface portions of impact structures, while impacted meteorites provide examples of a much wider range of surface and subsurface impactite materials than we can directly sample thus far through solar system exploration. </p><p> This report examines three facets of the impact record preserved in terrestrial impact craters and in meteorites. First, it looks at the macroscopic structure of the Sutters Mill meteorite, a brecciated regolithic CM chondrite that preserves a three-dimensional record of the one of the most primitive known impact gardened surfaces in the solar system. The report details distinct lithologies preserved in the meteorite and the ways in which these lithologies reflect impact and alteration processes, with the intention of contextualizing and illuminating the wider body of recently published instrumental work on the stone by the current authors and others. Second, this dissertation presents a detailed analysis of the origin and nature of unique sub-spherical `round rocks' commonly associated with the surface exposed sediments at the proposed Weaubleau impact structure, in west-central Missouri. Third, and finally, the dissertation looks at the nature of impact evidence for small impact pits and craters on earth. Unambiguously proving the impact origin of sub-kilometer terrestrial impact craters has presented significant historical challenges. A systematic analysis of field reports for all widely recognized sub-km terrestrial craters addresses both the nature of compelling evidence for impact origin for structures in this size range and the adequacy of the existing record of evidence for currently recognized structures.</p>

<p> Lakes formed in the Ays&eacute;n region of southern Chile after the retreat of mountain glaciers, beginning by at least ~17,900 cal yrs BP, contain numerous late-glacial and Holocene tephra layers derived from >70 eruptions of the volcanoes in the region, including Hudson, the southernmost in the Andean Southern Volcanic Zone (SVZ). Sediment cores from six of these lakes each contain an unusually thick late-glacial age tephra layer, which based on its distribution and bulk trace-element composition was derived from a large explosive eruption of the Hudson volcano between 17,300 and 17,440 cal yrs BP, and is termed Ho. In these cores, located ~100 km northeast of Hudson, the Ho tephra layers range between 35 to 88 cm in thickness. Comparison with three previously documented large explosive Holocene Hudson eruptions (H1, H2, H3 1991 AD) suggests that Ho was larger, with an estimated tephra volume of >20 km3, the largest post-glacial eruption documented for any volcano in the southern Andes. In total, Hudson has erupted &ge;45 km³ of pyroclastic material in the last ~17,500 years, making it the most active volcano in the southern Andes in terms of the total volume of pyroclastic material erupted since the beginning of deglaciation in the region. Chemical stratification is not seen in the Ho deposits, but this eruption was bi-modal, with a much greater proportion of dark glassy basaltic-andesite dense fragments and pumice, which range between 55 to 59 wt % SiO₂, and volumetrically less significant lighter colored dacite pumice with 66 wt % SiO₂. In contrast, H1 was andesitic in composition, H2 was more felsic than H1, being composed essentially of dacite, and although H3 in 1991 AD was again bi-modal, it erupted a much smaller proportion of mafic compared to felsic material than Ho. Thus, the repetitive large explosive eruptions of Hudson volcano have evolved to progressively less mafic overall compositions from late-glacial to historic times, and their volumes have decreased. All analyzed phases of different Hudson eruptions, have similar Sr-isotopic composition (0.70444 &plusmn; 0.00007), indicating that crystal-liquid fractionation rather than crustal assimilation was the main process responsible for these chemical variations.</p>