Radial cracks around inclusions: a program to calculate P-T paths with respect to elastic properties of minerals

Abstract Radial cracking around inclusions in a matrix originated by their differential elastic behavior allows the development of a new method for reconstructing the evolution of P-T paths during metamorphism. The appearance of radial cracking is a function of the variation of the elastic parameters between the matrix and inclusion, the initial P-T conditions of inclusion entrapment and the component of isothermal decompression characteristic for a retrograde path. The program RADCRA is written in FORTRAN 77 and presents a general form to calculate the different P-T evolutions for a matrix and an inclusion during metamorphism. Necessary input data are the elastic properties of each mineral: bulk moduli, their pressure and temperature derivatives, and some P-T points which describe the metamorphic path. The output is composed by the different P-T evolutions for the matrix and the inclusion. Calculation of prograde paths stops at the moment when the pressure in the matrix is equal to or greater than the inclusion's pressure. Calculation of retrograde paths stops if the radial crack conditions are satisfied or if the calculated P-T paths are explored completely and radial cracks never appear.