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MSPG 2010. A trip through the geographic time scale in the not so magical school bus. BRYAN COUNTY AREA. Dexter Sandstone. Approximately 90 million years old Kwd (Cretaceous System, Gulfian Series, Woodbine Formation, Dexter Member, Dexter Sandstone)
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MSPG 2010 A trip through the geographic time scale in the not so magical school bus. .
Dexter Sandstone • Approximately 90 million years old • Kwd (Cretaceous System, Gulfian Series, Woodbine Formation, Dexter Member, Dexter Sandstone) • Sandstone is formed from sediment cemented together from particles found in shallow oceans • Yellowish-brown, fine to medium grained, clay ironstone beds
BRYAN COUNTY AREA ……..
PawPaw Sandstone – McNutt Limestones 40 to 45 million years The PawPaw Sandstone and McNutt Limestone are found in the Bokchito Formation of the Cretaceous Period. PawPaw Sandstone allows water to seep through. Under the PawPaw layer the McNutt Limestone holds the water. As a result the water backs ups through the sandstone to the surface. This provides a constant flow of water allowing for the growth of cattails on the side of the road.
SOPER LIMESTONE Soper limestone lies between the Weno and Denton Shale
Kiamichi Formation • Dark gray to black fissile shales interbedded in upper parts with thin beds of yellow-gray, fossilferous limestones forming the “shell beds” composed of abundant textgryphae navia. • Thickness of layer: 30-40 feet • Oldest rock formation in the Cretaceous Period seen on Day 1. The fact that we found this Kiamichi Formation is a testimony to the amount of erosion that has taken place over the past 65 million years in Bryan County.
Antlers Sandstone White to yellow-brown Ferruginous Crossbedded Non fossililerous Line- to medium-grained sandstone Poorly cemented Friable pack sand: Interbeds of gray to black to purple Ferruginous clay Found in the Trinity Group of the Cretaceous Period Unique Characteristics – Used by the Cardinal Glass Company
Woodford Shale • From the Mississippian-Divonian Period (MDsw) • 360-408 million years old • Formed from water particles settling and cementing together in deeper ocean areas • Varied in color: light & dark gray, yellow, rusty • Indicator for oil and natural gas • Phosphate nodules present
Granitic Gneiss • Medium to fine-grained • Pervasive metamorphic textures
Ordovician Dolomite This rock was found in the Cool Creek McKenzie Hill Formation. Approximate age 505 – 438 million years. Environment of deposition Deep ocean. It is non-clastic. It is composed of mineral magnesium instead of pure calcium carbonate, therefore it does not react to hyrdrochloric acid as dramatically as other limestone. This picture was taken at the Blue River Hunting and Fishing area.
Grandodiorite • Precambrian • Medium-grained gray : hornblende-biotite
Tishomingo Granite About 1.3 billion years old Used for the ground floors of the state capitol in Oklahoma City
West Spring Creek Limestone • Tombstone Topography • Limestone: tan to gray • Chert nodules scattered throughout formation • Ordovician Period (Ow), 438-505 million years old • Mostly sea during that time • Lower Zone (224ft) • South limb of the West Spring Creek Anticline
Butterly Dolomite • Oldest member of the upper Arbuckle Group • Located at the Ordovician/Cambrian boundary • Pink/gray • Medium to coarse grained sandy dolomite • Contains milky quartz
Kindblade Formation/West Spring Creek Formation • Tectonic breccia in the Kindblade • The breccia is found in the Ordovician period
Collins Ranch Conglomerate South on I35 to first turnout, at the entrance-I35-marker 29, north end west side-wet turnout Graben and syncline, Conglomerate pebbles and cobbles ranging in age from West Spring Creek to Reagan Sandstone, deposited into a graben The Conglomerate is from the Pennsylvania period 320-286 million years ago
West Spring Creek Formation/Collins Ranch Conglomerate • Fault line for the north boundary of the Graben runs north of the road to the sign
West Spring Creek Formation • Marker 25 ft. below top of Kindblade Limestone, one side of marker Kindblade Limestone [OK], one side is West Spring Creek Limestone [OW] • Ordovician 438-505 million yrs. • Gray, fine grainedthick bedded • Quartzose Sandstone marks the base of the West Spring Creek North limb of the West Spring Creek Anticline
Kindblade Formation • Ordovician Period, (Ok) • 438-505 million years ago • Mostly sea at that time
Royer Dolomite • Cambrian Period (Cry), only sample • 505-545 million years old • Mostly sea at that time • Pink to gray in color • Massive Dolomite