2018/02/09

Tennessee Mississippian Strata: Pennington Formation

Pennington Formation

Guest author: Hali Steinmann

Lithology of the upper Mississippian Pennington Formation
The Pennington Formation is a Mississippian-aged rock unit consisting of red and green shale and siltstone, fine-grained dolomite, dark grey limestone, and calcareous sandstone (Rodgers 1953; Milici 1974; Milici et al 1979). Inconsistency in thickness of the formation (30 to 150 m or 100 to 500 ft) is the result of a regional disconformity between Mississippian and Pennsylvanian strata, i.e. an undulating erosional surface atop the Pennington Formation (Rodgers 1953). East of the Cumberland Plateau in Tennessee, the Pennington Formation is relatively thick and is primarily composed of terrigenous clastic deposits, while on the western escarpment of the Cumberland Plateau in central Tennessee it is thinner and more calcareous (Milici 1974; Milici et al. 1979). These lithologic differences indicate variations in the environment of deposition (tidal flat, tidal channel, levee, and intertidal environments), and variations in the amount of overburden removed during an erosive period prior to the deposition of Pennsylvanian rocks (Milici 1974; Ettensohn and Chesnut 1984; Bergenback 1993).
Main Borehole, Disconformity at Warren Point sandstone (Pennsylvanian) and Pennington formation (Mississippian) WH19, Tennessee

Stratigraphic Context and the Cumberland Plateau Aquifer System
The Pennington Formation rests atop the massive and highly karstified Bangor limestone and is overlain disconformably by permeable yet poorly soluble Pennsylvanian-aged clastic rocks (Figure 1) (Rodgers 1953; Crawford 1965, Knoll et al. 2015). The disconformity at the contact between upper Mississippian and basal Pennsylvanian beds is characterized by a gently undulating topographic surface with up to 30 meters of local relief, vertic paleosols, breccias containing Mississippian and Pennsylvanian aged rocks, and paleokarst consisting of dolines, solution pans, collapse features, and solutionally enlarged joints (Driese et al. 1994; Humbert 2001; Knoll et al. 2015). These indicate an erosional episode with extensive karstification prior to the deposition of Pennsylvanian clastic sequences (Milici et al. 1979; Bergenback 1993). Cross sections by Milici et al. (1979) show the variation in lithology of the Pennington Formation across the region (Figure 2). The western escarpment of the plateau has appreciable limestone units, while to the north and east the Pennington consists of primarily shale with very thin interbedded limestones (Milici et al. 1979). Units underlying the Pennington Formation, i.e. the Bangor and Monteagle limestones, tend to be more consistent in lithology and thickness throughout the Cumberland Plateau physiographic province (Brahana and Bradley 1989). 
Pennington Formation, US 70, White Co, TN

Distribution of the Pennington Formation
Pennington Formation

Pennington Caves

All data presented courtesy of Tennessee Cave Survey, 2017.



Geology
Count
Noteworthy Caves
Pennington Formation 328 Welch-Bowling, Lockwood
Pennington Formation and Bangor Limestone 6
Pennington, Bangor, Hartselle, St Louis   1 Rumbling Falls
Gizzard Group & Pennington Formation 3


Summary Statistics on Pennington Caves*
Min Max Mean Stdev
Length 8 17657 557.54 1709.81
Depth 2 156 24.21 19.98
Deepest Pit 0 78 4.38 11.93
Number of Pits 0 2 0.16 0.39
Elevation 680 2580 1396.52 233.40
*Represents caves formed exclusively in the Pennington Formation



Description
Count
Entrance Type
Bottleneck/small but bells out
1
Chimney or climb 40
Crawl 102
Extremely big, 20 feet+ 22
Large, walk in 70
Pit 29
Stoop or duck walk 63
Very wide pit, 20 feet+ 1
Entry Status Government owned 65
Government park 25
Private property 238
Equipment Handline 4
Normal gear 267
Rope/Prusik/Rappel 44
Wet/Wading (not swim) 8
Wetsuit 5
Field Indication Flat level ground 1
Hillside 37
In bluff or outcrop 152
Inflowing stream 14
Roadcut 6
Sink 44
Spring 48
Wet-weather streambed 25
Topographic Indication Contour distortion 4
Inflowing stream (sink) 1
Marked as cave 3
No indication 309
Sink 8
Spring 3


Pennington Formation Fossils

identified_name
identified_rank
accepted_name
accepted_rank
early_interval
max_ma
min_ma
Allorisma sp.
genus
genus
Chesterian
339.4
318.1
Anthracospirifer cf. leidyi
species
species
Chesterian
339.4
318.1
Archimedes sp.
genus
genus
Chesterian
339.4
318.1
Aviculopecten sp.
genus
genus
Chesterian
339.4
318.1
Brachiopoda indet.
phylum
phylum
Chesterian
339.4
318.1
Bryozoa indet.
phylum
phylum
Chesterian
339.4
318.1
species
species
Chesterian
339.4
318.1
species
species
Chesterian
339.4
318.1
Chonetes sp.
genus
genus
Chesterian
339.4
318.1
Crinoidea indet.
class
class
Chesterian
339.4
318.1
Diaphragmus ? sp.
genus
genus
Chesterian
339.4
318.1
species
species
Chesterian
339.4
318.1
Diaphragmus sp.
genus
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
Grammysia ? sp.
genus
genus
Chesterian
339.4
318.1
Nautiloidea indet.
subclass
subclass
Chesterian
339.4
318.1
Orthotetes sp.
genus
genus
Chesterian
339.4
318.1
Ovatia ? sp.
genus
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
Pelecypoda indet.
class
class
Chesterian
339.4
318.1
Pentremites sp.
genus
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
Polypora sp.
genus
genus
Chesterian
339.4
318.1
Posidonomya sp.
genus
genus
Chesterian
339.4
318.1
Punctospirifer ? sp.
genus
genus
Chesterian
339.4
318.1
Punctospirifer sp.
genus
genus
Chesterian
339.4
318.1
Solemya sp.
genus
genus
Chesterian
339.4
318.1
Spirifer sp.
genus
genus
Chesterian
339.4
318.1
species
genus
Chesterian
339.4
318.1
Data Provider
The Paleobiology Database
Data Source
The Paleobiology Database
Data License
Creative Commons CC-BY
License URL
Documentation URL
Data URL
Access Time
Wed 2018-01-17 00:40:52 GMT
Title
PBDB Data Service
Parameters:
strat
Pennington Fm
timerule
major
taxon_status
all
Hali Steinmann authored Lithology of the upper Mississippian Pennington Formation and Stratigraphic Context and the Cumberland Plateau Aquifer System. Many thanks to her for her contributions to this document.
Bibliography
ETTENSOHN, FRANK R. “An Alternative to the Barrier-Shoreline Model for Deposition of Mississippian and Pennsylvanian Rocks in Northeastern Kentucky: Summary.” GSA Bulletin, vol. 91, no. 3, Mar. 1980, pp. 130–35, doi:10.1130/0016-7606(1980)91<130:aattbm>2.0.CO;2.

The Paleobiology Database. https://paleobiodb.org/#/. Accessed 10 Feb. 2018.
White, Stan. “Tennessee Cave Survey.” Tennessee Cave Survey, http://www.subworks.com/tcs/. Accessed 16 Feb. 2018.
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