BOUNDARIES, FEEDBACK, SELF-ORGANIZATION AND WEATHERING OF THE PIKES PEAK GRANITE, COLORADO

The development of boundary surfaces such as a weathering front is a self-organization response driven by thermally active media (granite, water, atmosphere, biota) in the presence of gravity (driving force) and atomic forces (resisting forces). Gravity forces precipitation, drives erosional processes and determines sediment distribution. Strong and electromagnetic forces that determine the strength of molecular bonding control media properties such as viscosity, rigidity and chemical activity. A greater understanding of feedback mechanisms at geomorphic boundary surfaces can be gained through a STEMOBS analysis of each bounding media by addressing seven factors: spatial, temporal, energy, mass, intrinsic organization, boundaries and scale. Weathering of the Pikes Peak Granite displays self-organization through features such as corestones, grus, tors and unconsolidated granite residuum (spatially defined boundaries at macroscales) greater than 30 m below the surface. The granite (mass) is predisposed to breakdown through the development of microfractures related to the diapiric intrusion and dilation (gravitational energy) and cooling (thermal energy) of the Pikes Peak Batholith over 1.04 Ga (time). The thermally charged atmosphere with water and oxygen in contact with the granite has interacted since the Eocene (40 Ma) by chemically altering biotite at molecular scales to produce hydrobiotite that expands to increase permeability and cause an exponential increase in alteration rates. Other weathering phenomena involving boundary feedback and self-organization include unloading fractures, case hardening and corestone complexes.