Core of Texas Creek batholith is porphyritic granodiorite here named Texas Creek granodiorite in Hyder district, southeastern AK. Forms south slope of ridge north of Texas Glacier for about 3 mi west of international boundary. Contact between Boundary and Texas Creek granodiorites is just west of international boundary. Contact with Hyder quartz monzonite strikes northward across valley about 0.75 mi from foot of Thumb Glacier. Shown on geologic map of Hyder district as of Jurassic or Cretaceous age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
"Named by Buddington (1929), p.22) for excellent exposures along Texas Creek." p.16. Report includes detailed lithology and petrographic analyses. K-Ar ages on biotite and hornblende gave discordant ages from biotite which was chloritized. Thus hornblende age of about 200 Ma is probably closer to age of emplacement. This suggests age of Late Triassic or Early Jurassic for unit.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
Age is Late Triassic and Early Jurassic based on K-Ar determinations of approximately 210 to 202 Ma on hornblende and of approximately 195 to 193 Ma on zircons from samples of unit.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
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