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420k Field Trip 5, ‘06. Mapping a Basal Cretaceous Nonconformity, Mason Mt. W.M.A., Mason Co., TX. basal C nonconformity. Detailed geo. map. basal K nonconformity. Mason Mt. W.M.A. To Austin. Location & General Geology. Paleozoic sedimentary rxs. pC metamorphic & igneous rocks.
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420k Field Trip 5, ‘06 Mapping a Basal Cretaceous Nonconformity, Mason Mt. W.M.A., Mason Co., TX
basal C nonconformity Detailed geo. map basal K nonconformity Mason Mt. W.M.A. To Austin Location & General Geology Paleozoic sedimentary rxs. pC metamorphic & igneous rocks Penn. NE-SW Faults K carbonates & clastics
Geo of Mason Area pC Katemcy Pluton~ 1.1 Ga basal C nonconformity K Carbonates & Clastics pC Lost Creek Gneiss~1.25 Ga basal K nonconformity pC Valley Spring Gneiss~1.3 Ga pC Packsaddle Schist~1.25 Ga C-O Sediments(e.g. Riley, Ellenburger) 1:100k (“Detailed”) Geology, Mason Area Penn. Mason Fault Zone
Camping site Wildlife Management Area Geo of the WMA Mason Mountains
Approx. Mapping Area 1:24k Topo., Mason Mts. Camping site
! 1:24k Topo. & Geo., Mason Mts. Note mismatch of geo. and topo.
1900’ 1960’ 1880’ ! 1:24k Topo. & Geo., Mason Mts. Strike Lines • Southwest dip; pCtm over Kh = Overturned nonconformity!!?
100m UTM grid 1:10k Base Map, Mason Mts.
Your weekend mapping goals: • Is the extant digital G.A.T. Llano sheet correct? • If not, what are the true geometric relationships and how do they map out? Deliverables (before returning to Austin): • Geologic Map: showing nonconformity, K-unit contacts, and strikes/dips • Cross section A-A’