EXPERIMENTAL ANALYSIS OF FRACTURE PATTERNS

Research Article| March 01, 1955 EXPERIMENTAL ANALYSIS OF FRACTURE PATTERNS ERNST CLOOS ERNST CLOOS (Address of the Retiring President of The Geological Society of America) Search for other works by this author on: GSW Google Scholar Author and Article Information ERNST CLOOS (Address of the Retiring President of The Geological Society of America) Publisher: Geological Society of America Received: 19 Nov 1954 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1955, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1955) 66 (3): 241–256. https://doi.org/10.1130/0016-7606(1955)66[241:EAOFP]2.0.CO;2 Article history Received: 19 Nov 1954 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ERNST CLOOS; EXPERIMENTAL ANALYSIS OF FRACTURE PATTERNS. GSA Bulletin 1955;; 66 (3): 241–256. doi: https://doi.org/10.1130/0016-7606(1955)66[241:EAOFP]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract All existing fractures can be imitated in four scale models which show tension or shear fractures with or without rotational deformation. These four experiments can easily be produced by deforming soft clay which rests on a moving square of wire cloth.En echelon zones are easily produced by placing clay above the edge of a moving tin plate. Tension and shear fractures open in the flexure zone and are unfailing indicators of relative displacement.Normal or gravity faults occur preferably above domes and anticlines or other areas of distension. Salt-dome patterns may readily be imitated by pushing a plug into a clay model from below. A systematic study of fracture anomalies may prove useful in the detection of areas of uplift above salt domes.Longitudinal and transverse normal faults in North dome of the Kettleman Hills are readily imitated in a clay model and may be due to vertical uplift with or without lateral compression. The en echelon arrangement of the Kettleman Hills is probably not due to north-south movement toward a weak zone trending northwest. True en echelon folds would trend west-northwest but not nearly north-northwest. The echelon arrangement may be only the alternation of folds or may be due to northeast-southwest movements, possibly in combination with subcrustal blocks and faults.The San Andreas-Garlock fault system can be imitated only if considerable rotation has opened the angle between shear planes from near 60° to 90° or to 120°. Asymmetry of the fault pattern suggests clockwise rotation. A more complicated experiment in which three blocks are placed as suggested by Ralph Reed seems to come nearer to a fitting imitation but may still include too large an area.The value of experimentation lies in experience gained by the experimenter rather than in the exact duplication of known fracture patterns. The intense occupation with mechanical principles and the close visible relationship between cause and effect is sobering as well as stimulating. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.