GLG 201 Final: Final Exam Study Guide
Document Summary
What is the difference between primary and secondary porosity: porosity is the total volume of open spaces in sediment/rock that groundwater can fill. Primary porosity was originally formed in the material, like vesicles in basalt, voids in sediment, and framework in open reefs. Secondary porosity develops later from fracturing, faulting, or dissolution: permeability is how easily water can flow between the pores based on how well connected they are. Between the two zones is the capillary fringe that wicks water upward: the depth of the water table depends on the environment. Humid, rainy settings have a water table level closer to the surface while more arid settings or areas in a drought have a deeper water table. It can be in any path, not always straight lines. Recharge areas are where water flows downward (topographic highs) and infiltrates the soil, and discharge areas are where it flows upward exits the surface (topographic lows).
