1. PSRDPSRD presents www.psrd.hawaii.edu/July08/H-chondrite-parent.html Dewar area Heating, Cooling, and Cratering: One Asteroid’s Complicated Story

2. PSRDPSRD presents www.psrd.hawaii.edu/July08/H-chondrite-parent.html Heating, Cooling, and Cratering: One Asteroid’s Complicated Story The simplest way to explain the sequence of textural and mineralogical changes among H chondrites is by thermal metamorphism in a hot body. This ‘onion-shell’ structure results in the most metamorphosed rocks residing the deepest and cooling the slowest.

3. PSRDPSRD presents www.psrd.hawaii.edu/July08/H-chondrite-parent.html Heating, Cooling, and Cratering: One Asteroid’s Complicated Story Two studies of chondrite ages show that the onion shell model is consistent with observations. Cooling is slower for the more metamorphosed chondrites.

4. PSRDPSRD presents www.psrd.hawaii.edu/July08/H-chondrite-parent.html Heating, Cooling, and Cratering: One Asteroid’s Complicated Story Some cooling rates derived from compositional zoning in metallic minerals are consistent with the onion-shell structure. But others are not. Why? Perhaps a large impact event brought slower-cooling rock closer to the surface and buried faster-cooling rock.