You are currently viewing the summary.View Full Text
In Earth sciences, the critical zone represents the intersection of the biosphere with the atmosphere, hydrosphere, and lithosphere (1, 2). The myriad interactions and feedbacks among these systems assure us of a world with considerable complexity, in which the critical zone varies in thickness, mineralogy, permeability (3), and structure of ecosystems (4). It is no wonder, then, that we lack a general theory of how the critical zone works. On page 534 of this issue, St. Clair et al. (5) argue that we must take the broadest possible view of, and acknowledge a role for, largescale tectonic stresses in guiding the pattern of cracking of rock in the subsurface.