Transcript Puckett GSA Stillwater 2015x

Hanson et al. 2012
3D Projection of the Southern Mid-Continent Basement-Rock Surface
Washita Valley Fault and Overthrust Penetrations
Western Arbuckle Mountains
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42 overthrust drilling penetrations
Accessible samples from 21 wells
26.6 km of uncorrelated igneous section
Puckett et al., 2014
Oklahoma Geological Survey
Guidebook 38
2014
34 km Non-Correlated Cross Section
Mafic Rock Photomicrographs
Mafic Rock Geochemistry
Characterized as broadly transitional
tholeiitic basalts to andesites from
multiple overlapping eruptive
systems. Similar to OIB and other
continental flood basalts originating
from an enriched mantle source.
Pan Am Newberry
Pan Am Williams
Pan Am Jarman
Sec. 13-T1N-R3W
Sec. 20-T1N-R2W
Sec. 19-T1N-R2W
Modified from Brueseke et al. 2014
Rhyolite Photomicrographs
Rhyolite Geochemistry
Dominantly rhyolites and peralkaline rhyolites
Highly fractionated – Depleted Sr, P, Ti - Typical A-type signature
Typical within Plate, A-type, consistent with
emplacement in alaucogen type setting
Outcrop-Based Generalized Cooling Unit Diagram
Surface Exposures of the Carlton Rhyolite in the Wichita Mountains
From Puckett et al. 2011
Rhyolite Cooling Unit
Pan American Oil Co. Moore #1-A Sec.20 T1N-R2W
Rhyolite Glassy Flow Margin
Kaiser Francis/Westheimer-Neustadt Chapman #1 Sec.9-T2S-R2E
Rhyolite
glassy flow
margin
(Dark Brown
cuttings)
Flow interior
40 m below
glassy margin
sample above
Gamma Ray, Induction Log, and Lithologic Log
COHO Resources Story #4 Sec. 18-T1N-R2W
W
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l
Phreatomagmatic Interval – Magma in Contact With Ground Water
Pan American Oil Co. Whyte #1 Sec. 21-T1N-R1W
1.14 km
426 m
Clastic Section
Pan Am Jar man #1
Sec. 19-T1N-R2W
Washita Valley Fault and Overthrust Penetrations
Western Arbuckle Mountains
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
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42 overthrust drilling penetrations
Accessible samples from 21 wells
26.6 km of uncorrelated igneous section
Puckett et al., 2014
1.2 km Cumulative Volcaniclastic Interval Intercalated with Rhyolite
Frankfort Oil Co. Sparks Ranch #1 Sec. 32-T1S-R1W
Post Volcanic Sedimentation close to the Rift Axis
Frankfort Oil Co. Sparks Ranch Sec. 32-T1S-R1W
Reagan Islands
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Positive relief features that resisted inundation until Latest Cambrian/Early Ordovician
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Identifiable by the absence of Reagan Sandstone resulting in Arbuckle Group
carbonates unconformably overlying the Early Cambrian volcanic rocks.
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Also found in the Wichita Mountains at Balley Mountain and the Slick Hills
Modified from Campbell and Weber 2006
2.48 km beneath surface
SOHIO Traub #1-3
Sec. 3-T6N-R14W
6.8 km NNE of Bally Mountain
415 m thick basalt interval
with 35 m rhyolite dike/sill
104 m thick basalt interval
229 m thick basalt interval
POSSIBLE
FAULT
FAULT
6.19 km beneath surface
Helmerich & Payne McNutt Unit #1
Sec. 23-T9N-R26W
Surface
2.91 km of
Permian and
Pennsylvanian
sedimentary rocks
including Granite
Wash
4.9 km
(minimum)
Normal fault
2.49 km
2.91 km
1.44 km of
Diabase, Diorite,
and Granite
4.35 km
850 m of
Gabbro
280 m of metamorphic rocks
3 m core of amphibolite and
quartzo-feldspathic gneiss
Poss. Fault indicated
on Caliper log
5.48 km Total Depth
5,436.5 m
5,467.8 m
Photo by OGS Core Facility Staff
Penetratively folded tonalitic gneiss
Hornblende
Biotite
Sericitized plagioclase
Light green areas on hornblende represent partial
retrogression to actinolite. PPL Field width 5mm
Amphibolite with migmatitic quartz-feldspar patch.
Summary
 The Southern Oklahoma Aulacogen contains a minimum emplaced volume of
250,000 km3.
 Igneous activity was voluminous, strongly bimodal, and intercalated. Coeval mafic
and felsic volcanism phases overlap.
 Felsic magmas were A-type, mafic magmas have an EMI-OIB signature.
 Eruption products are lava-dominated - Rhyolitic pyroclastic deposits are limited to
thin beds between flows - Basalt pyroclastic deposits seem to be primarily sourced
from phreatomagmatic eruptions.
 Cratonic-sourced sedimentation into the rift was active during volcanism and defines
a negative topographic profile after volcanism ceased.
 Intercalated rhyolites and basalts are present in the subsurface throughout the
aulacogen.