Development and application of some quantitative stratigraphic techniques to the Coos Bay coalfield, a Tertiary fluvio-deltaic complex in southwestern Oregon

• Main Author: Titus, Willard Sidney, III
• Format: Others
• Published: PDXScholar 1987
• Subjects: Geophysical well logging > Data processing; Stratigraphic Geology > Statistical methods; Stratigraphic Geology > Tertiary; Coal > Geology > Oregon > Coos County; Geology; Geophysics and Seismology; Stratigraphy
• Online Access: https://pdxscholar.library.pdx.edu/open_access_etds/3730; https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=4739&context=open_access_etds

A computer technique for interpreting geophysical logs of drill-holes in quantitative lithologic terms has been developed and tested on the deposits of the late Eocene Coaledo Formation, a well-studied fluvio-deltaic complex in southwestern Oregon. The technique involves the use of induced and natural gamma logs for separation of coal and claystone from coarse-grained detrital rocks and the use of the ratio of resistivity and natural gamma responses (defined here as the "grain size index") to divide the coarse elastic rocks into a series of textural classes corresponding to the Wentworth-Odden particle size scale.