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The Talladega Slate Belt
By Steven Stokes, Daniel Rollins, Matthew Sahawneh, Krystal Russell,
and Ashley Stewart
• Cheaha State Park • Located in northern Clay and southwestern
Cleburne counties• May 20-25
Where We’re Going
Location:North-Eastern
AlabamaNear the town of
Sylacauga, Alabama
Talladega Slate Belt
• Composed primarily of low-grade metamorphic rocks
• Bounded to the Northwest by a foreland fold and thrust fault system known as the Talladega fault or the Columbiana fault
• To the southeast is marked by high grade metamorphism caused by both the Hollins Line fault and the Goodwater-Enitachopco fault system.
Talladega Slate Belt
• Alleghanian thrust sheet• Metamorphosed to lower green schist facies
during the Acadian orogeny and thrust above the foreland fold and thrust belt.
• Believed to be associated with main pulse of Early to Middle Devonian Acadian orogeny.
Sequences
• Composed of 4 lithologic groups – Hillabee Greenstone– Sylacauga Marble– Talladega– Kahatchee Mountain
Hillabee Greenstone
• 2.6 kilometers thick • Ordovician Age 457m.y.• Greenstones and Greenschists – What is a greenstone?– Bulk of sequence
• Albite, Actinolite, Epidote, Zoisite, Clinozoisite, and Chlorite
• Tabular and extrusive
Sylacauga Marble
• Jumbo Dolomite at base• Dolomite and Calcite marbles • Nature of Dolomite • Nature and use of marble
Sylacauga Marble
• Below Lay Dam Formation of Talladega Group– Unconformity between the two– Diamictites – What is diamictite?
• Lack of fossils make age correlation difficult • Cambrian to Ordovician
Talladega Group
• Clastic • Divided into several
formations– Lay Dam Formation– Cheaha Quartzite Member – Erin Slate Member – Butting Ram Sandstone – Jemison Chert
Lay Dam Formation
• Overlies Sylacauga • Oldest • Silurian to Lower Devonian. • Greenish-gray, slightly calcareous sericite
phyllites and slates• Sandstone bodies small, grade into phyllites• Rapid deposition.
Cheaha Quartzite Member
• Metasandstone in Lay Dam Formation • Sandy phyllites and coarse grained quartzites • Fines upward • Devonian • Primary Structures– Horizontally bedded, graded intervals– Low angle pebbles structures– Channel fill deposits– Tabular and trough bedding
Erin Slate Member
• Also member of Lay Dam Formation • Thick highly carbonaceous phyllites or slate• Less mature than Cheaha Quartzite member • Lagoon depositional environment
Butting Ram Sandstone
• Thin green chloritic, arkosic metasandstone • Subrounded to rounded quartz sand • Feldspathic• Tidal channel deposits • Very discontinuous • Points of elevated crests
Jemison Chert Interval
• Above Butting Ram Sandstone • Interbedded white, paper thin quartzites • Intercalated with black graphitic phyllites of Erin
Slate • White to pale light gray, very dense, very fined
quartzite• Complexly folded• Intense deformation• Lower Devonian
Kahatchee Mountain Group
• Named Mountain Group because it can be found in the mountains northwest of Syllacuaga.
• Width is highly variable.• Carboniferous in age. (Spores found that
indicate carboniferous in metamorphic frontblock of sequence)
Formations within the Kahatchee Mountain Group
• Waxahatchee Slate• Brewer Phyllite• Wash Creek Slate• Sawyer Limestone• *Chilton Fault
Deformational Phase 1 – D1
• F1 folds are invariably tight to isoclinal• Interlimb angle is 20 to 0 degrees• They are assymetric with stort limbs are 20%
shorter than long limbs• It has S1 foliations
Deformational Phase 2 and 3
• F2 folds can be only seen in thin section• F3 folds are small folds 1mm to 1cm• F3 they distort both the compositional layers• F3 crenulation fold axial plane with S1-S2
surface
Deformational Phase 4 – D4
• F4 folds can be seen on regional map• F4 folds cut through the F1 folds• F4 axial plane strikes northwest to
southeast• A major faulting event
Questions?