A method of estimating at least one mechanical property value of a rock formation in the geologic past. In one embodiment, a correlation model is generated which correlates at least one mechanical property with a porosity value and a composition value relative to a first rock type. An estimation of a past porosity value and a past composition value is then generated for the rock formation at a point of time in the past. A mechanical property value at the point of time in the past is identified in the correlation model based on the estimated past porosity and past composition values.