Structural Geology: Brunton: Strike and Dip: Field: Alta Tunnel скачать в хорошем качестве

Structural Geology: Brunton: Strike and Dip: Field: Alta Tunnel

How to measure strike and dip with the Brunton transit (compass). This video covers how to measure strike and dip of a joint (overhanging surface) at Alta Tunnel. The video was recorded at the tunnel on December 5, 2020. After measuring strike and dip of the joint, I realized that my transit was adjusted for declination (5° W) in Chattanooga, TN, where it was most recently used. I note this at the end of the video and correct the measurement of strike for the declination (12° E) at Alta tunnel. Alta tunnel, on the south side of Big Cottonwood Canyon, Wasatch Range, near Salt Lake City, UT, is a 4,000-ft-long mine tunnel that was excavated between 1875 and 1935 to pursue ores of Pb, Ag, and Zn. Alta tunnel and associated mine workings have been repurposed as an underground water reservoir, as described at https://canyonwater.com/ and https://www.ksl.com/article/28033253/... This video employs what I refer to as the “American right-arm rule” for expressing the strike and dip of planes; looking to the strike direction, the plane dips in the direction of the observer’s right arm, i.e. clockwise from the strike direction. This is very different from the “British right-hand rule”, as it is sometimes defined. For example (from the video), consider a plane that strikes to the north (or south) and dips to the east. By the right-arm rule used in this video, the strike would have to be expressed to the north in order to preserve the dip direction (to the east). Thus, a strike and dip of 356, 50 (or 356/50), expressed following the right-arm rule, is equivalent to N04W, 50E, using a quadrant notation for strike, or 356, 50 E, using azimuth, dip, and dip direction. Personally, I see no harm in including the dip direction with the right-arm rule. Doing so provides something of a safety net while taking notes and makes it equivalent to azimuth, dip, and dip direction. By yet another convention, that of dip and dip direction, this strike and dip (356, 50) is equivalent to 50, 086 (or 50/086). Also note that punctuation/delimiters (comma, space, slash, etc.) can vary. This video was produced during the winter of 2020-21, at the heart of COVID, as part of my effort to teach a field methods class, partially online. CHAPTERS (PARTS) 00:00 Intro 00:15 Setting of Alta Tunnel 01:05 Rock type, bedding, joints 02:12 Right-arm rule 02:50 Measuring strike 03:55 Measuring dip 05:25 Wrong declination