Fluvial deposits of the Sierra Ladrones Formation (Pliocene-Pleistocene) contain abundant elongate calcite concretions that are interpreted to have precipitated in the saturated zone parallel to the direction of groundwater flow. The orientation of these concretions is coincident with the orientation of the permeability correlation structure, as determined from architectural element mapping and permeameter measurements. In cases where the paleo-groundwater flow closely corresponds with the direction of fluvial deposition, measurement of concretion orientations in alluvial rocks and sediments may provide a means of rapidly estimating the major aids of the permeability correlation structure over large areas.
