New insights into the Early Cambrian igneous and sedimentary history of the Southern Oklahoma Aulacogen from basement well penetrations

Robert E. Puckett Jr., Richard E. Hanson, G. Randy Keller, Matthew E. Brueseke, Casey L. Bulen, Amy M. Eschberger, Stanley A. Mertzman

Hanson et al. 2012

3D Projection of the Southern Mid-Continent Basement-Rock Surface

Puckett et al., 2014

35 km

Washita Valley Fault and Overthrust Penetrations Western Arbuckle Mountains

42 overthrust drilling penetrations Accessible samples from 21 wells 26.6 km of uncorrelated igneous section

Oklahoma Geological SurveyGuidebook 38

2014

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Mafic Rock Photomicrographs

Mafic Rock Geochemistry

Pan Am Newberry Sec. 13-T1N-R3WPan Am Williams Sec. 20-T1N-R2WPan Am Jarman Sec. 19-T1N-R2W

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.

Modified from Brueseke et al. 2014

Rhyolite Photomicrographs

Rhy

olite

Geo

chem

istr

y

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 DiagramSurface 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

Well log interval from the COHO Resources Story #4 (18-1N-2W), showing gamma ray and induction logs and corresponding lithologic log.

Gamma Ray, Induction Log, and Lithologic LogCOHO Resources Story #4 Sec. 18-T1N-R2W

Phreatomagmatic Interval – Magma in Contact With Ground WaterPan American Oil Co. Whyte #1 Sec. 21-T1N-R1W

Clastic SectionPan Am Jar man #1Sec. 19-T1N-R2W

1.14

km

42

6 m

Puckett et al., 2014

35 km

Washita Valley Fault and Overthrust Penetrations Western Arbuckle Mountains

42 overthrust drilling penetrations Accessible samples from 21 wells 26.6 km of uncorrelated igneous section

1.2 km Cumulative Volcaniclastic Interval Intercalated with RhyoliteFrankfort Oil Co. Sparks Ranch #1 Sec. 32-T1S-R1W

Post Volcanic Sedimentation close to the Rift AxisFrankfort Oil Co. Sparks Ranch Sec. 32-T1S-R1W

Reagan Islands

• Positive relief features that resisted inundation until Latest Cambrian/Early Ordovician

• Identifiable by the absence of Reagan Sandstone resulting in Arbuckle Group carbonates unconformably overlying the Early Cambrian volcanic rocks.

• Also found in the Wichita Mountains at Balley Mountain and the Slick Hills

Modified from Campbell and Weber 2006

FAULT

POSSIBLE FAULT

SOHIO Traub #1-3Sec. 3-T6N-R14W6.8 km NNE of Bally Mountain

2.48 km beneath surface

6.19 km beneath surface

415 m thick basalt interval with 35 m rhyolite dike/sill

104 m thick basalt interval

229 m thick basalt interval

Helmerich & Payne McNutt Unit #1

Sec. 23-T9N-R26W

2.91 km

Surface

4.35 km

4.9 km(minimum)

Normal fault

5.48 km Total Depth

2.91 km ofPermian and Pennsylvanian sedimentary rocks including Granite Wash

1.44 km ofDiabase, Diorite, and Granite

850 m of Gabbro

3 m core of amphibolite and quartzo-feldspathic gneiss

Poss. Fault indicated on Caliper log

2.49 km

280 m of metamorphic rocks

5,436.5 m

5,467.8 mPhoto by OGS Core Facility Staff

Penetratively folded tonalitic gneiss

Amphibolite with migmatitic quartz-feldspar patch.

Hornblende Biotite

Light green areas on hornblende represent partial retrogression to actinolite. PPL Field width 5mm

Sericitized plagioclase

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.

Summary