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

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The start of our Berkeley Field Tradition

Lawson’ s fi rst fie ld cl ass 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

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Rhyolites and Basalts Dacites

SiO2 (Silica)

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Brimhall 2004

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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)

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Source region for rhyolite magmas involves continental crust: Franciscan or its derivatives eg Orinda

Rhyolite Monoliths

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Are the Rhyolite and Dacite related ? Use Zircons ZrSiO4

Fractional Fusion ?

(IUGS Classification))

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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

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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

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http://www.metzgerwillard.us/Setup.aspx

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3-D Physical standards- analogous to chemical standards NIST

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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

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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

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