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April 3, 2016 Weekly Geology Guess

April 3, 2016
Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:
Discussion on Alabama Geology, Part 5 of the Alabama Piedmont, as a PDF is attached.  Discussion below.
This article provides a good overview of Alabama Geology.  By Nick Tew and Sandy Ebersole of the Geological Survey of Alabama.

http://www.encyclopediaofalabama.org/article/h-1549

While an undergraduate, 1967-1968, the Piedmont was considered a complex black hole.  Tony Neathery (deceased) and others were in the process of unraveling this geologic mystery.
It is still complex with many heated geologic arguments, and holds many more secrets.
Enjoy the discussion and please throw you 2 cents or quarter’s worth of comments and questions.
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Minerals and Rocks – The Good Life from the Ground
 
“If it ain’t grown, it has to be mined”
Topic of the Week:  Geology of Alabama (Part 5 of 8)
The Alabama Piedmont Province

Geologic Maps of Alabama
https://images.search.yahoo.com/yhs/search;_ylt=A0LEVvx838hWGSAAsqIPxQt.;_ylu=X3oDMTByMjB0aG5zBGNvbG8DYmYxBHBvcwMxBHZ0aWQDBHNlYwNzYw–?p=Geology+of+Alabama&fr=yhs-befrugal-002&hspart=befrugal&hsimp=yhs-002

Part 5 will cover the Piedmont Physiographic Province of Alabama.  Attached as a PDF File.

http://www.encyclopediaofalabama.org/article/h-1309

“Chewacla State Park, located just south of Auburn in Lee County, is in the Southern Piedmont Upland and contains the oldest known rock in Alabama, a gneiss dating from 1.05 billion years ago.”
Districts
“The Piedmont consists of two districts: the Northern Piedmont Upland and the Southern Piedmont Upland. The Northern Piedmont Upland is underlain by slate, quartzite, phyllite, marble, gneiss, and schist, and the rugged nature and high elevations of the northwestern part of the upland are caused by varying rates of erosion of these rock types. The Southern Piedmont Upland is underlain by schist, gneiss, and amphibolite.
These rocks resist erosion equally, accounting for the flatness of the area.”
Rocks
The Alabama Piedmont is made up of the crystalline rocks, igneous and metamorphic.
Structure:  Excellent write up in Lost Worlds of Alabama by Jim Lacefield, 2013.
p. 62:  “The Piedmont rocks are highly altered and provide much information regarding the building of the Appalachian Mountains.”  At least three ancient mountain-building episodes have been identified.”
When continents are torn apart and slammed together, bits and pieces of these major tectonic events are left as evidence of plate tectonics.
p. 171:  “Such events include the “accreted terranes (volcanic island arcs, granite plutons, and cooked ancient sea floor.”  “Just past the Georgia Line is a fault zone of highly metamorphosed rocks.  This fault zone marks the approximate point of contact in the collision of continents that fused African Gondwana to Laurasia.”
This type of geology is not easy to decipher since some of the work requires seismic imaging.
Natural Resources
The two main mineral resources include gold and marble.  A whole host of other minerals have been mined on a lesser scale — copper, graphite, iron ore, galena, muscovite, pyrite, talc, and an assortment of gemstones.
Fossils
Fossils are rare in the Piedmont due to either the igneous source rock or the metamorphism of the host rock.
But in places, Mississippian Age fossils have been identified in the low grade metamorphic rocks.
Alabama Marble
The Sylacauga Marble Group is considered to be Ordovician-Cambrian carbonate shelf sequence.  The Sylacauga Marble Group belong or are associated with the Valley and Ridge Province adjacent to the north.  The marble present in the quarries correlate with limestones in the Conasauga Formation.  Metamorphism occurred either in the late Devonian to early Carboniferous (Acadian-Neoacadian orgogenisis) = “Mountain Building”

http://www.encyclopediaofalabama.org/article/h-2047

Attached PDF File.
Page 1.  Welcome
Page 2.    Geologic Time Scale
Page 3.  Alabama Geologic Map
Page 4.    Piedmont Physiograpic Province
Page 5.    Piedmont Road Map
Page 6.    Piedmont Geologic Map
Page 7-8.    Oldest Gold Mine in Alabama, Devil’s Backbone, Tallapoosa County
Page 9-10.    Alabama Marble Quarry, Sylcauga
Page 11.    Folded Gneiss Rock
Page 12.    Alabama Coastal Plane, Part 6 of 8, to be continued next week.
Thanks,
Randy
References:
–    Lost Worlds of Alabama by Jim Lacefield.
–    Wikipedia
–    Geological Survey of Alabama
–    Any many others that I am indebted to.
–    Also my Professors and mentors, most of whom are now deceased.
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Another Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R
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“No copyright infringement intended.
The rights belong to their respective owners”
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Copyright Disclaimer: Under Section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.

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Author’s Request:  If you see any pictures that you know the source and photographer, let me know immediately.  Thanks!  R

Images have been searched by TinEye Reverse Image Search.  http://tineye.com/

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And as always, “The Devil is in the Details”!
Next week, Episode 6, we will venture into the Alabama Coastal Plane.
 
Have A Great Week!
AL Minerals.  AL Marble, White with Fault, Sylacauga.

AL Minerals. AL Marble, White with Fault, Sylacauga.

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AL Minerals. AL Marble. White Marble Quarry, Sylacauga.

AL Minerals.  AL White Marble, Sylacauga.

AL Minerals. AL White Marble, Sylacauga.

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AL Minerals. Almandine Garnet. Alan Guisewite’s Mineral Collection Images

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AL Minerals. Kyanite. Turkey Heaven, Cleburne Co.

AL Minerals.  Magnetite, Tallapoosa Co.  GSA.

AL Minerals. Magnetite, Tallapoosa Co. GSA.

AL Minerals.  Muscovite, Cleburne Co..

AL Minerals. Muscovite, Cleburne Co..

AL Minerals.  Pyrite on Marble, Sylacauga. AL.  www.johnbetts-fineminerals.com

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AL Minerals.  Star Blue Quartz.

AL Minerals. Star Blue Quartz.

AL Minerals.  Tantalite (Rare Earths). Coosa Co.

AL Minerals. Tantalite (Rare Earths). Coosa Co.

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