WorldWide Drilling Resource

180 degrees. Longitude Correction - East-west cor- rections made to observed magnetic intensities by subtracting the earth’s nor- mal field. Longitudinal - Said of an entity extended lengthwise. Longitudinal Dune - A long, narrow sand dune, usually symmetrical in cross profile, oriented parallel with the direction of the prevailing wind; commonly forms behind an obstacle in an area where sand is abundant and the wind is strong and con- stant. Longitudinal Fault - A fault whose strike is parallel with that of the general structur- al trend of the region. Longitudinal Joint - A steeply dipping plane in a pluton (a large body of intru- sive igneous rock) which is oriented par- allel to the lines of flow. 24 JULY 2015 WorldWide Drilling Resource ® &% ! "" * "(%$ ))) (" $( ' & $ %# # " (" $( $ ( " !" !! ! &% ! % ! (" $( & $ $ $ " ! $ $ ! ! $ ! $ # $ $ $ Frequently-Used Geological Terms Part 41 Glossary Adapted from the Dictionary of Geological Terms L - Continued Logan’s Line - A structural discontinuity along the northwestern edge of the Northern Appalachians, between com- plexly deformed rocks on the southeast and undisturbed rocks on the northwest. Named for its discovery by Sir William Logan in 1863. Logging - The act or process of record- ing a log. Also refers to a method or tech- nique by which subsurface formations are characterized relative to depth by measurements or observations on the rocks of a borehole. Lognormal Distribution - A frequency distribution whose logarithm follows a normal distribution. Longitude - Angular distance between the meridian (north-south line used as a zero point) of a place and the prime meridian of Greenwich, England (which has a longitude of zero degrees), meas- ured east or west to a maximum value of More terms to come next month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