"白雪岩质石灰岩" can be translated as "snow-white dolomitic limestone" or more literally as "white snow-like dolomitic limestone" depending on the intended emphasis. Here, “dolomitic limestone” refers to a type of limestone that contains a significant amount of dolomite, and “snow-white” or “white snow-like” conveys the white, snow-like appearance of the rock.
If the term "白雪岩质" is more about the texture or appearance resembling snow rather than the actual color being pure white, "snow-like textured dolomitic limestone" could also be a fitting translation. However, "snow-white dolomitic limestone" is a common and straightforward way to convey the idea.