Thermal history of meteorites

Composition and Thermal History of the Ivb Iron Meteorites

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...

Iron meteorites: Crystallization, thermal history, parent bodies, and origin

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, ...

Thermal history and origin of the IVB iron meteorites and their parent body

We have determined metallographic cooling rates of 9 IVB irons by measuring Ni gradients 3 lm or less in length at kamacite–taenite boundaries with the analytical transmission electron microscope and by comparing these Ni gradients with those derived by modeling kamacite growth. Cooling rates at 600–400 C vary from 475 K/Myr at the low-Ni end of group IVB to 5000 K/Myr at the high-Ni end. Sizes...

Ar-Ar and I-Xe Ages and the Thermal History of IAB Meteorites

Studies of several samples of the large Caddo County IAB iron meteorite reveal andesitic material, enriched in Si, Na, Al and Ca, which is essentially unique among meteorites. This material is believed to have formed from a chondritic source by partial melting and to have further segregated by grain coarsening. Such an origin implies extended metamorphism of the IAB parent body. New 39Ar40Ar ag...

Universe: Thermal History