Joints are opening-mode fractures formed as a consequence of brittle deformation of rock masses in the Earth's crust. A review paper summarizing geoscience research on jointing of rocks undertaken over the past 100 years has been presented by Pollard and Aydin (1988). Joints serve as indicators of local stress field orientations because their paths are always perpendicular to the local maximum tensile (minimum compressive) stress.Joints also serve as pathways for subsurface fluid flow. Fluid flow along natural joint networks plays an important role in aquifers and hydrocarbon reservoirs, and is a major concern for the stability of engineering sites. Studying joints and jointing has been a major theme of the Stanford Rock Fracture Project. For an overview of our research on joints and jointing, here we list the major topics and give the related publications.
Growth and density of joints in basaltic lava flow:
Aydin, A., and DeGraff, J. M., 1988, Evolution of polygonal fracture patterns in lava flows, Science 239 (4839), 471-476.
DeGraff, J.M., and Aydin, A. 1993. Effect of cooling rate on growth increments and spacing of thermal contraction cracks. Journal of Geophysical Research 98, 6411-6430.
DeGraff, J.M., Long, P.E., and Aydin, A. 1989. Use of joint-growth directions and rock textures to infer thermal regimes during solidification of basaltic lava flows. Journal of Volcanology and Geothermal Research 38, 309-324.
Lore, J., Aydin, A., and Goodson, K., 2000. A Deterministic Methodology for Prediction of Fracture Distribution in Basaltic Multi-flows. Journal of Geophysical Research, in press.
Lore, J., Gao, H., and Aydin, A., 2000, Viscoelastic Thermal Stress in Cooling Basalt Flows. Journal of Geophysical Research, v. 105, no. B10, p. 23695-23709.
Joint propagation path and remote stress field:
Cooke, M. L., and Pollard, D. D., 1996, Fracture propagation paths under mixed mode loading within rectangular blocks of polymethyl methacrylate, Journal of Geophysical Research 101, 3387-3400.
Olson, J., and Pollard, D. D., 1989, Inferring paleostresses from natural fracture patterns: a new method, Geology (Boulder), 17, 345-348.
Renshaw, C. E., and Pollard, D. D., 1994, Are large differential stresses required for straight fracture propagation paths? Journal of Structural Geology 16, 817-822.
Conditions for a joint to propagate across or arrest at an interface:
Helgeson, D.E., and Aydin, A. 1991. Characteristics of joint propagation across layer interfaces in sedimentary rocks. Journal of Structural Geology 13, 897-911.
Renshaw, C. E., and Pollard, D. D., 1995, An experimentally verified criterion for propagation across unbounded frictional interfaces in brittle, linear elastic materials, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 32, 237-249.
Localization and clustering of joints:
Cruikshank, K. M., and Aydin, A. 1994. Role of fracture localization in arch formation, Arches National Park, Utah. Geological Society of America Bulletin 106, 879-891.
Cruikshank, K. M., and Aydin, A. 1995. Unweaving the joints in Entrada Sandstone, southwest limb of the Salt Valley anticline, Arches National Park, Utah, U.S.A. Journal of Structural Geology 17, 409-421.
Jointing and faulting:
Cooke, M.,Mollema, P., Pollard, D.D., and Aydin, A., 2000, Interlayer slip and joint localization in East Kaibab Monocline, Utah: field evidence and results from numerical modeling: in Cosgrove, J.W. & Ameen, M.S. (eds.), Forced Folds and Fractures, Geological Society, London, Special Publications, v. 169, p. 23-49.
Kattenhorn, S. A., Aydin, A., and Pollard, D. D., 2000, Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress fields, Journal of Structural Geology 22, 1-23.
Joint interaction and formation of echelon joint arrays:
Du, Y., and Aydin, A. 1991. Interaction of multiple cracks and formation of echelon crack arrays. International Journal of Analytical and Numerical Methods in Geomechanics 15, 205-218.
Olson, J.E. 1993. Joint pattern development: Effects of subcritical crack growth and mechanical crack interaction. Journal of Geophysical Research 98, 12,251-12,265.
Olson, J., and Pollard, D.D. 1991. The initiation and growth of en echelon veins. Journal of Structural Geology 13, 595-608.
Pollard, D.D., Zeller, S., Olson, J., and Thomas, A. 1990. Understanding the process of jointing in brittle rock masses. In: W.A. Hustrulid and G.A. Johnson, eds., Rock Mechanics Contributions and Challenges. Proceedings of the 31st U.S. Symposium, A.A. Balkema, Rotterdam, 447-454.
Renshaw, C. E., and Pollard, D. D., 1994, Numerical simulation of fracture set formation; a fracture mechanics model consistent with experimental observations, Journal of Geophysical Research 99, 9359-9372.
Thomas, A. L. and Pollard, D. D., 1993, The geometry of echelon fractures in rock: implications from laboratory and numerical experiments, Journal of Structural Geology 15, 323-334.
Joint spacing and aperture in layered rocks:
Bai, T., and Pollard, D.D., 1999, Spacing of fractures in a multilayer at fracture saturation: International Journal of Fracture: Letters in Fracture and Micromechanics, v. 100, p. L23-L28.
Bai, T., and Pollard, D.D, 2000a, Fracture spacing in layered rocks: a new explanation based on the stress transition. Journal of Structural Geology, v. 22, p. 43 -57.
Bai, T., and Pollard, D.D, 2000b, Closely spaced fractures in layered rocks: initiation mechanism and propagation kinematics. Journal of Structural Geology, v. 22, p. 1409-1425.
Bai, T., Pollard, D.D, and Gao, H., 2000a, Explanation for fracture spacing in layered materials: Nature, v. 403, p. 753-756.
Bai, T., Pollard, D. D., and Gao, H., 2000b, Spacing of edge fractures in layered materials. International Journal of Fracture, v. 103 (4), p. 373-395.
Bai, T., Pollard, D.D, and Gross, M.R., 2000c, Mechanical prediction of fracture aperture in layered rocks: Journal of Geophysical Research, v. 105, p. 707-721.
Wu, H., and Pollard, D.D. 1992. Propagation of a set of opening-mode fractures in layered brittle materials under uniaxial strain cycling. Journal of Geophysical Research 97, 3381-3396.
Wu, H., and Pollard, D.D. 1995. An experimental study of the relationship between joint spacing and layer thickness. Journal of Structural Geology 17, 887-905.
Wu, H., and Pollard, D.D. 1991. Fracture spacing, density, and distribution in layered rock masses: Results from a new experimental technique. In: J.-C. Roegiers, ed., Rock Mechanics as a Multidisciplinary Science. Proceedings of the 32nd U.S. Symposium, A.A. Balkema, Rotterdam, 1175-1184.