Browsing by Author "Rosenberg, Gary D."

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    Breccia of Frog Lakes : reconstructing Triassic volcanism and subduction initiation in the east-central Sierra Nevada, California
    (2014-03-12) Roberts, Sarah Elizabeth; Barth, Andrew, 1958-; Rosenberg, Gary D.; Filippelli, Gabriel M.
    The Antler and Sonoma orogenies occurred along the southwest-trending passive Pacific margin of North America during the Paleozoic concluding with the accretion of the McCloud Arc. A southeast-trending sinistral transform fault truncated the continental margin in the Permian, becoming a locus for initiation of an east-dipping subduction zone creating the Sierran magmatic arc. Constrained in age between two early Triassic tuff layers, the volcanic clasts in the breccia of Frog Lakes represent one of the earliest records of mafic magmatism in the eastern Sierra Nevada. Tholeiitic rock clasts found in the breccia of Frog Lakes in the Saddlebag Lake pendant in the east central Sierra Nevada range in composition from 48% to 63% SiO2. Boninites produced by early volcanism of subduction initiation by spontaneous nucleation at the Izu-Bonin-Mariana arc are more depleted in trace element concentrations than the clasts while andesites from the northern volcanic zone of the Andes produced on crust 50 km thick have similar levels of enrichment and provide a better geochemical modern analogue. Textural analysis of the breccia of Frog Lakes suggest a subaqueous environment of deposition from a mature magmatic arc built on continental crust > 50 km thick during the Triassic. The monzodiorites of Saddlebag and Odell Lakes are temporal intrusive equivalents of the breccia of Frog Lakes and zircon geochemistry indicates a magmatic arc petrogenesis.
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    Cladistic Analysis of the Paleozoic Bryozoan Families Monticuliporidae and Mesotrypidae
    (2011-03-16) Adamczyk, Amber Diane; Pachut, Joseph F., 1950-; Tedesco, Lenore P.; Rosenberg, Gary D.
    Two closely related families of Ordovician bryozoans, the Monticuliporidae and the Mesotrypidae, collectively contain 12 genera that have been reclassified repeatedly by various authors. Using published illustrations for the type specimens of each genus, character states for 267 morphological attributes were coded. Cladistic results were compared between the programs PAST and PAUP, and contrasted with phenetic methods. PAUP produced the shortest trees, with better summary index values and low homoplasy. Phenetic results varied, depending largely on the similarity measures used. Cladistic analysis produced five tree topologies, the most parsimonious of which consisted of a monophyletic crown group, representing Family Monticuliporidae, and a paraphyletic stem group that included the genera Mesotrypa and Diazipora. The crown group includes the genera Aspidopora, Atactoporella, Acantholaminatus, Peronopora, Homotrypella, Homotrypa, Gortanipora, Monticulipora, Prasopora, and Prasoporina. The paraphyletic stem group matches Astrova’s concept of Family Mesotrypidae. These results suggest the placement of all 12 genera in a single Family Monticuliporidae. Future studies that include data for additional closely related genera in might provide a clearer picture of familial assignments for these, and other, stenolaemate genera.
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    Introduction: Nicolaus Steno and earth science in early modern Italy
    (Florence University Press, 2021) Dominici, Stefano; Rosenberg, Gary D.; Earth and Environmental Sciences, School of Science
    A group of scientists interested in history of science and fascinated by the figure of Nicolaus Steno (1638-1686) gathered in Florence for the 350th anniversary of the publication of his De solido intra solidum naturaliter contento prodromus dissertationis. A public conference held at Palazzo Fenzi on 16 October 2019 and a geological fieldtrip on the following day were occasions to discuss different points of view on the last published work of the Danish natural philosopher, dedicated to "solids naturally enclosed in other solids" (De solido intra solidum naturaliter contento, or De solido in short). The title of the gathering, "Galilean foundation for a solid earth", emphasized the philosophical context that Steno found in Florence, where in 1666-1668 he established tight human and philosophical bonds with renowned Italian disciples of Galileo Galilei and members of the Accademia del Cimento. For participants to the 2019 gathering, the Museum of Natural History of the University of Florence, hosting some of Steno's geological specimens, and the region of Tuscany itself, formed the perfect location to discuss the phenomena that Steno had observed from 1666-1668, the motivations for his research, the methodology of his discovery and, generally stated, the European scientific context which informed his inquiry. Some of the talks given in that meeting are included within this volume, kindly hosted by Substantia, International Journal of the History of Chemistry published by the Florence University Press. In addition some of the invited speakers who were unable to attend, also contributed a paper to this publication. The collection is about earth science in the early modern period, when the study of minerals, rocks, and the fossilized remains of living things did not yet form a distinct path to knowledge about earth history, but was an integral part of the wider "philosophy of nature".
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    INVASIVE SPECIES AND PANNE ECOSYSTEMS: THE EFFECTS OF ATMOSPHERIC POLLUTION
    (2008-04-10T14:30:08Z) Nazareth, Cheryl; Filippelli, Gabriel M.; Souch, Catherine J.; Rosenberg, Gary D.
    Pannes are rare intradunal wetlands. Though small, they are known to exhibit extremely diverse and sensitive vegetation and are home to a number of reptile and amphibian species. In the United States, pannes are known to occur only around the Great Lakes Basin and Cape Cod. At Indiana Dunes National Lakeshore, the fifteen known pannes have an unusually large variety of plant species for such a small geographic area and provide habitat for plant species found nowhere else in Indiana. However, these sensitive ecosystems have been exposed to over a century of atmospheric pollutants from the surrounding steel and coal industries. Since 1986, the native vegetation of the area is slowly being replaced by invasive species like Phragmites australis and Typha spp. This study attempts to explain the shift in vegetation. Pannes in two other locations, at a distance from the industrial complex, were used as control sites as they were not expected to be exposed to the same levels of heavy metal concentrations. Four of the fifteen pannes at the Indiana Dunes National Lakeshore, two of the four pannes at Sleeping Bear Dunes National Lakeshore, Michigan, and two of the three pannes at Warren Dunes State Park, Michigan, were studied, resulting in a total of eight pannes. The pannnes were stratified and sampled by hydroperiod. Surface soil samples and sediments at depth, were recovered from each of the pannes considered in this study and analyzed for heavy metal, phosphorus, carbon and nitrogen content. Results show that high levels of organic matter coupled with high nutrients and high metals, in the soil, are a combination that may be considered a risk factor for future invasion of pannes by invasive species. It appears to be difficult for the native vegetation to deal with the high metals and high nutrients which are deleterious to the native vegetation and facilitate establishment of invasive vegetation which is more tolerant to the altered geochemical conditions.