DR DATA REPOSITORY

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Helena Robertson
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1 DR DATA REPOSITORY ANALYTICAL TECHNIQUES Zircons were separated from 3-5 kg samples using standard crushing and grinding techniques, followed by three rounds of magnetic separation at increasing intensities, then liquid separation utilizing lithium metatungstate and methylethyl iodine. A split of ~ zircon grains was mounted in epoxy for each sample, providing a random sample of the population. Grains were polished to about half their original thicknesses and imaged with reflected light and cathodoluminescence to reveal internal zoning. Most grains display indistinct magmatic zoning or are relatively homogenous; rims were analyzed for grains showing any zoning. Most examined zircons are pale yellow, lack inclusions, and shapes range from euhedral to subrounded. No obvious age groupings were evident based on grain size or morphology. Mounts were gold-coated prior to analysis, and each sample was sputtered using a primary beam of O 2- ions with a spot size of ~25 μm. Counts of Zr 2 O, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 238 U, 248 ThO, and 254 UO were measured from the secondary beam. Standard zircons SL13 and CZ3 were employed as concentration standards. Duplicate analyses of standard zircon R33 (419 Ma) were used for age corrections. All reported zircon ages presented in Table DR 2 were calculated using the Squid data-reduction program of Ludwig (2001). Grains younger than 1100 Ma were corrected using 207 Pb and ages were determined from the 206 Pb/ 238 U ratio, whereas zircon grains older than 1100 Ma were corrected using 204 Pb and the 207 Pb/ 206 Pb ratio. Common Pb corrections were made using the two-stage average crustal Pb model of Stacey and Kramers (1975). Most grains are concordant (i.e., analyses overlap concordia at 2 σ confidence levels) and in the diagrams of Figure 6, only zircons concordant at 2 σ confidence levels are shown. Most SIMS ages lie between Ma, with a few scattered Proterozoic ± late Archean ages. REFERENCES Ludwig, K.R., 2001, User s Manual for Isoplot/Ex, Version 2.49, A Geochronological toolkit for Microsoft Excel: Berkeley Geochronology Center Special Publication No. 1a, 55p.

2 Stacey, J. S., and Kramers, J.D., 1975, Approximation of terrestrial lead isotopic evolution by a two-stage model: Earth and Planetary Science Letters, v. 26, p DATA REPOSITORY FIGURE CAPTIONS Figure DR1. Photomicrographs (plane light, field of view 2.2 x 1.5 mm) of the six analyzed metagraywackes allow comparison of their contrasting textures: the upper El Cerrito and the Skaggs Springs Schist are thoroughly reconstituted metamorphic rocks, whereas original clasts are apparent in the four structurally lower, weakly recrystallized specimens. See text for brief petrographic descriptions of these six investigated rocks.

3 U

4 Table DR1. Visually estimated modes of metagraywacke samples in volume % grains SBM AT HPSZ LEC UEC NS-10 quartz albite white mica stilpnomelane 0 tr biotite 1 3 tr tr 0 chlorite epidote tr 1 tr tr 0 0 titanite tr 0 0 tr 1 tr opaques+limonite lawsonite pumpellyite tr 0 0 glaucophane jadeitic pyroxene siltstone+shale chert volcanic rock tr serpentinite tr 0 0 carbon. matter total specimen location depositional age SBM San Bruno Mountain 52 Ma AH Albany Hill (Novato Q terrane) 83 Ma HPSZ Hunters Point shear zone 97 Ma LEC lower El Cerrito 100 Ma UEC upper El Cerrito 102 Ma NS-10 Skaggs Springs Schist 144 Ma

5 Table DR2. Detrital zircon data from SHRIMP analysis r r r r r r r r r r r r r r r r r r r r r r r

6 767-2-r r r r r r r r r r r r r r r r r r r r r r r r

7 767-3-r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r

8 767-3-r r r r r core

9 UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC

10 UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC UEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC

11 LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC LEC

13 UEC=Upper El Cerrito sample LEC=Lower El Cerrito sample 767-1= Albany Hill sample (Novato Quarry terrane) 767-2= Hunters Point shear zone sample 767-3= San Bruno Mountain sample 741-1= Skaggs Spring Schist sample

Cloudland gneisses, Mars Hill terrane, NC-TN: New SHRIMP U-Pb ages for detrital zircon and. monazite

GSA DATA REPOSITORY 2013302 J.N. Aleinikoff et al. Late Mesoproterozoic (ca. 1.0 Ga) deposition of protoliths of the high grade Carvers Gap and Cloudland gneisses, Mars Hill terrane, NC-TN: New SHRIMP