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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Marine Sediment Record From The East Antarctic Margin Reveals Dynamics Of Ice Sheet Recession, Amy Leventer, Eugene Domack, Jennifer Pike, Catherine Stickley, Eleanor Maddison, Stefanie A. Brachfeld, Patricia Manley, Charlie Mcclennen
Marine Sediment Record From The East Antarctic Margin Reveals Dynamics Of Ice Sheet Recession, Amy Leventer, Eugene Domack, Jennifer Pike, Catherine Stickley, Eleanor Maddison, Stefanie A. Brachfeld, Patricia Manley, Charlie Mcclennen
Stefanie Brachfeld
The Antarctic shelf is traversed by large-scale troughs developed by glacial erosion. Swath bathymetric, lithologic, and chronologic data from jumbo piston cores from four sites along the East Antarctic margin (Iceberg Alley, the Nielsen Basin, the Svenner Channel, and the Mertz-Ninnis Trough) are used to demonstrate that these cross-shelf features controlled development of calving bay reentrants in the Antarctic ice sheet during deglaciation. At all sites except the Mertz-Ninnis Trough, the transition between the Last Glacial Maximum and the Holocene is characterized by varved couplets deposited during a short interval of extremely high primary productivity in a fjordlike setting. Nearly …
Magnetic Properties Of A Sediment Core From Andvord Drift, Emily Youcha, Stefanie A. Brachfeld
Magnetic Properties Of A Sediment Core From Andvord Drift, Emily Youcha, Stefanie A. Brachfeld
Stefanie Brachfeld
No abstract provided.
Magnetic Granulometry Of Igneous And Metasedimentary Rocks From Northern Graham Land, Antarctic Peninsula, Stefanie A. Brachfeld, Anne Grunow, Emily Youcha
Magnetic Granulometry Of Igneous And Metasedimentary Rocks From Northern Graham Land, Antarctic Peninsula, Stefanie A. Brachfeld, Anne Grunow, Emily Youcha
Stefanie Brachfeld
No abstract provided.
Rock-Magnetic Analysis Of Sediments From Andvord Bay, Stefanie A. Brachfeld
Rock-Magnetic Analysis Of Sediments From Andvord Bay, Stefanie A. Brachfeld
Stefanie Brachfeld
No abstract provided.
Multicomponent Cubic Oxide Exsolution In Synthetic Basalts: Temperature Dependence And Implications For Magnetic Properties, Julie A. Bowles, Lisa Tatsumi-Petrochilos, Julie E. Hammer, Stefanie A. Brachfeld
Multicomponent Cubic Oxide Exsolution In Synthetic Basalts: Temperature Dependence And Implications For Magnetic Properties, Julie A. Bowles, Lisa Tatsumi-Petrochilos, Julie E. Hammer, Stefanie A. Brachfeld
Stefanie Brachfeld
Although the compositional unmixing of cubic-structured iron oxides has profound effects on the magnetic properties of rocks that contain them, a basic understanding of the kinetics and thermodynamics of this process has not been achieved in experimental studies due to sluggish reaction rates in binary oxide phases. Exploiting the fact that many natural Fe-oxides contain multiple additional cations, including Ti, Mg and Al, we perform novel “forward” laboratory experiments in which cubic-cubic phase exsolution proceeds from initially homogeneous multicomponent oxides. A variety of Fe-Ti-Mg-Al cubic iron oxides were nucleated and grown in synthetic, multicomponent basalt under different ƒO2 environments, and …
Magnetic And Petrologic Characterization Of Synthetic Martian Basalts And Implications For The Surface Magnetization Of Mars, Julie A. Bowles, Julie E. Hammer, Stefanie A. Brachfeld
Magnetic And Petrologic Characterization Of Synthetic Martian Basalts And Implications For The Surface Magnetization Of Mars, Julie A. Bowles, Julie E. Hammer, Stefanie A. Brachfeld
Stefanie Brachfeld
A suite of synthetic Martian basalts is generated with the objective of providing fundamental material properties data for use in modeling and interpretation of mission data. We systematically evaluate the effects of major element composition, oxygen fugacity (ƒO2), and cooling rate on phase chemistry and magnetic mineralogy, grain size, and intensity of remanent magnetization. The range of experimental compositions and ƒO2 are chosen to bracket the range expected in the Martian crust; our results should therefore span the range of possible mineralogies, textures, and magnetic properties in rapidly cooled Mars crustal materials. Two starting compositions are used for …
Contribution Of Multidomain Titanomagnetite To The Intensity And Stability Of Mars Crustal Magnetic Anomalies, Stefanie A. Brachfeld, David Cuomo, Lisa Tatsumi-Petrochilos, Julie A. Bowles, Deepa Shah, Julie E. Hammer
Contribution Of Multidomain Titanomagnetite To The Intensity And Stability Of Mars Crustal Magnetic Anomalies, Stefanie A. Brachfeld, David Cuomo, Lisa Tatsumi-Petrochilos, Julie A. Bowles, Deepa Shah, Julie E. Hammer
Stefanie Brachfeld
Two basalts with compositions relevant to the crusts of Mars and Earth were synthesized at igneous temperatures and held at 650°C for 21 to 257 days under quartz-fayalite-magnetite ƒO2 buffer conditions. The run products are germane to slowly cooled igneous intrusions, which might be a significant volumetric fraction of the Martian crust and carriers of magnetic anomalies in the Southern Highlands. Both basalts acquired intense thermoremanent magnetizations and intense but easily demagnetized anhysteretic remanent magnetizations carried by homogeneous multidomain titanomagnetite. Hypothetical intrusions on Mars composed of these materials would be capable of acquiring intense remanences sufficient to generate the …