Fluid flow in chondritic parent bodies: Deciphering the compositions of planetesimals

Alteration of the Allende meteorite caused shifts in oxygen isotope ratios along a single mass fractionation Line, if alteration was caused by aqueous fluid, the pattern of oxygen isotope fractionation can be explained only b y flow of reactive water down a temperature gradient. Down-temperature flow of aqueous fluid within planetesimals is sufficient to explain the mineral ogical and oxygen isotopic diversity among CV, CM, and CI carbonaceous chon drites and displacement of the terrestrial planets from the primordial slop e 1.00 line on the oxygen three-isotope plot.