Calculations of mantle convection generally use constant rates of internal heating and time-invariant core-mantle boundary temperature. In contrast, parameterized convection calculations, sometimes called thermal history calculations, allow these properties to vary with time but only provide a single average temperature for the entire mantle. Here I consider three-dimensional spherical convecti...

For more than six decades, physiological ecologists have intensively studied diverse aspects of lizard thermal biology. Nevertheless, a recent review notes that prior studies have generally ignored gender differences in body temperatures, thermal sensitivity, or other aspects of thermal biology. We concur that gender differences have been ignored and should be examined: if gender differences pr...

We review the crystallization of the iron meteorite chemical groups, the thermal history of the irons as revealed by the metallographic cooling rates, the ages of the iron meteorites and their relationships with other meteorite types, and the formation of the iron meteorite parent bodies. Within most iron meteorite groups, chemical trends are broadly consistent with fractional crystallization, ...

Starting with Kelvin there have been many controversies and paradoxes associated with the evolution of the Earth. These are not faith-based controversies, in the ordinary sense; they are based on calculations and assumptions which are a form of faith . Present-day heat flow is determined by the amount and distribution of radioactive elements, their secular decline with time, the delay between h...

Editor: T.M. Harrison Non-arc basalts of Archean and Proterozoic age have model primary magmas that exhibit mantle potential temperatures TP that increase from 1350 °C at the present to a maximum of ∼1500–1600 °C at 2.5–3.0 Ga. The overall trend of these temperatures converges smoothly to that of the present-day MORB source, supporting the interpretation that the non-arc basalts formed by the m...

M. I. Petaev, A. Meibom, C. Perron, and B. Zanda, Dept. of the Geophysical Sciences, University of Chicago (5734 S. Ellis Ave., Chicago, IL 60637 USA; [email protected]), Dept. of Earth and Planetary Sciences, Harvard University (20 Oxford St., Cambridge, MA 02138 USA; [email protected]), Dept. of Geological and Environmental Sciences, Stanford University (Building 320, Lomita Mall,...

Introduction: Among the magmatic iron meteorites, group IVB irons have some unusual characteristics, such as high bulk Ni (15-18 wt%), high refractory elements (e.g., Ir), low volatile elements (e.g., Ga, Ge) [1, 2], fast cooling rates and a small parent body [3, 4]. IVB irons do not have a Widmanstatten pattern as in lower Ni IIIAB or IVA irons. Instead, IVB irons have a plessite structure wit...

ZnAl2O4 spinel powders were prepared using the Pechini or co-precipitation synthetic route and were then treated at different temperatures (600–1350 °C). These powders were characterised by X-ray diffraction, scanning electron microscopy (SEM), diffuse reflectance and luminescence measurements. SEM investigations and the X-ray patterns showed that the spinel crystallite size was dependent on th...

available online at http://meteoritics.org Microstructure and thermal history of metal particles in CH chondrites J. I. GOLDSTEIN1*, R. H. JONES2, P. G. KOTULA3, and J. R. MICHAEL3 1Department of Mechanical and Industrial Engineering, 313 Engineering Laboratory, University of Massachusetts, 160 Governors Drive, Amherst, Massachusetts 01003, USA 2Department of Earth and Planetary Sciences, Unive...

Using stereo generated topography of Dione, a moon of Saturn, we infer flexure across a prominent ridge on the leading hemisphere to estimate local elastic thickness and place constraints on Dione’s thermal evolution. Assuming topography is related to the flexing of a broken elastic plate, we estimate an effective elastic thickness of 3.5 ± 1 km. This local estimate is in good agreement with gl...