4/5/2010 EPS 101/271 Lecture 16: Dacite “Rhyolite” Source Region Geodetic Markers and Accuracy of the GPS units we use Chronology: 1871 Department formed by Joseph LeConte 1887 Charles Palache graduates from Berkeley High and enters Cal as a Freshman, continues on in graduate school 1892 Andrew Lawson teaches the first “systematic field geology class in the US” using Berkeley Hills 1893 Charles Palache publishes the results of the first doctoral thesis in geology at UC: “The Soda Rhyolite North of Berkeley” UC Bulletin of the Dept. of Geology, v. 1, p. 61-72 1902 Lawson and Palache publish “The Berkeley Hills- A Detail of Coast Range Geology” Bulletin of the Dept. of Geology,v. 2, p. 349-450 1 4/5/2010 The start of our Berkeley Field Tradition Lawson ’s first fie ld c lass 1892 Strawberry Creek Stadium Missing the Rhyolite Tuffs Hayward Fault Claremont Canyon Lawson and Palache’s map of the Berkeley Hills Global vs Local control on lithology Recall the explanation of the Miocene stratigraphic sequence Global climatic change Sudden global cooling FtiflFormation of polar ice caps Marine Regression causing the litho-sequence 2 4/5/2010 Rhyolites and Basalts Dacites SiO2 (Silica) 3 4/5/2010 Brimhall 2004 4 4/5/2010 Constraints on the Origin of Rhyolite Tuffs in the Berkeley/Oakland Hills Tecuya Formation in S CA Basalts Mixing lines as the result of ridge/trench collision Rhyolites Franciscan Initial Cole and Basu (1992) 5 4/5/2010 Source region for rhyolite magmas involves continental crust: Franciscan or its derivatives eg Orinda Rhyolite Monoliths 6 4/5/2010 Are the Rhyolite and Dacite related ? Use Zircons ZrSiO4 Fractional Fusion ? (IUGS Classification)) 7 4/5/2010 Indian Rock Diatreme 10.9 11.3 1303 old core 88.3 K and J Orinda Grizzly Peak Not very rounded-close to their source Euhedral Zircons: Dating rhyolitic magma crystallization Euhedral 11.3 Indian Rock Monoliths 10.0 Dacite Diatreme Grizzly Peak Dacite Tuffs Sibley Volcano Park Dacite Tuffs 8 4/5/2010 Indian Rock Detrital Zircons: Detrital Age, source region Euhedral Monoliths and provenance of persistent mineral grains Rhyodacite Diatreme Grizzly Peak Rhyodacite Tuffs Franciscan Provenance Orinda Formation Detrital T K J Tr Sibley Park Tuff Detrital Geodetic Markers 9 4/5/2010 http://www.metzgerwillard.us/Setup.aspx 10 4/5/2010 3-D Physical standards- analogous to chemical standards NIST 11 4/5/2010 12 4/5/2010 Click on the PID name eg HT1891 so that the NGS data sheet appears below. Be careful to observe which ellipsoid is referenced eg NAD83 is NAD83 Note: NADCONUS 83 CONUS not NAD27 W. USA 13 4/5/2010 This map was made at PID HT1891 using 80-10 second averaging times for the Globalsat BC-337 GPS with a SiRFstarIII chipset (WAAS) Systematic Error and accuracy (relative to HT1892)= 2.33 meters Random Error (relative to mean): Easting 1 = 0.73 m Northing 1 =1.63 m Systematic Sum random error and precision: Error (black) 1 =SQRT(ADE2+ADN2)= 1.79m Vector 2 m Accuracy 3 Total Error = Systematic +/- Random Error 1 Total Error = 2.33+/- 1.79m Data 1m Cloud 1 0.54 < Total Error < 4.12 m 2 0 <Total Error < 6.2 width 3 0< Total Error < 7.69 95% Precision 14.