378 research outputs found

    Groundwater geology of DeWitt, Piatt, and northern Macon Counties, Illinois

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    Contract report prepared for the Mahomet Valley Water AuthorityOpe

    Geological and geophysical maps of the Illinois Basin-Ozark Dome region

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    Map 1. Land surface topography -- Map 2. Bedrock topography -- Map 3. Surficial geology with shaded relief -- Map 4. Bedrock geology with bedrock topography -- Map 5. Structure contours of the top of the Pennsylvanian Springfield Coal and Bevier Coal (Missouri) -- Map 6. Structure contours of the top of the Mississippian-Devonian New Albany Shale and correlatives -- Map 7. Structure contours of the top of the Ordovician Trenton Limestone (or equivalent) -- Map 8. Structure contours of the top of the Precambrian -- Map 9. Isostatic gravity anomaly -- Map 10. Magnetic anomaly -- Map 11. Fault and fold traces -- Map 12. Earthquake epicenters 1804-2014.Ope

    The earthquake of September 2, 1999, in northern Illinois: big lessons from a small earthquake

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    An electrical earth resistivity survey in the Wabash River bottoms eastern Crawford County, Illinois

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    "March 2000."Includes bibliographical references (leaves 13-14)

    Observational evidence for a different IMF in the early Galaxy

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    The unexpected high incidence of carbon-enhanced, s-process enriched unevolved stars amongst extremely metal-poor stars in the halo provides a significant constraint on the Initial Mass Function (IMF) in the early Galaxy. We argue that these objects are evidence for the past existence of a large population of intermediate-mass stars, and conclude that the IMF in the early Galaxy was different from the present, and shifted toward higher masses.Comment: 14 pages, 1 color figure, accepted for publication on Ap

    Hydrogeology of the Silurian dolomite aquifer in parts of Northwestern Illinois

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    Solar Magnetic Field Signatures in Helioseismic Splitting Coefficients

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    Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that the frequency splitting is only due to rotation and a large scale magnetic field. We find that the data are best fit by a combination of a poloidal field and a double-peaked near-surface toroidal field. The toroidal fields are centered at r=0.999R_solar and r=0.996R_solar and are confined to the near-surface layers. The poloidal field is a dipole field. The peak strength of the poloidal field is 124 +/- 17G. The toroidal field peaks at 380 +/- 30G and 1.4 +/- 0.2kG for the shallower and deeper fields respectively. The field strengths are highly correlated with surface activity. The toroidal field strength shows a hysteresis-like effect when compared to the global 10.7 cm radio flux. The poloidal field strength shows evidence of saturation at high activity.Comment: 10 pages, accepted for publication in Ap
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