National Park Service

U.S. Department of the Interior

Natural Resource Stewardship and Science

Horseshoe Bend National Military Park

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2020/2158
ON THE COVER

The Tallapoosa River forms the namesake bend of Horseshoe Bend National Military Park. NPS photograph 

(from National Park Service 2014).

THIS PAGE

A reenactment cannon firing drill at Horseshoe Bend National Military Park. NPS photograph.
Horseshoe Bend National Military Park

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2020/2158

Michael Barthelmes

Colorado State University Research Associate

National Park Service Geologic Resources Inventory

Geologic Resources Division

PO Box 25287

Denver, CO 80225

July 2020

U.S. Department of the Interior

National Park Service

Natural Resource Stewardship and Science 

Fort Collins, Colorado
ii

The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes 

a range of reports that address natural resource topics. These reports are of interest and applicability to a 

broad audience in the National Park Service and others in natural resource management, including scientists, 

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This report is available from the Geologic Resources Inventory publications site and the Natural Resource Report 

publication series site. If you have difficulty accessing information in this publication, particularly if using assistive 

technology, please email irma@nps.gov

Please cite this publication as:

Barthelmes, M. 2020. Horseshoe Bend National Military Park: Geologic resources inventory report. Natural 

Resource Report NPS/NRSS/GRD/NRR—2020/2158. National Park Service, Fort Collins, Colorado. https://doi.

org/10.36967/nrr-2276835.

NPS 407/171160, July 2020
iii

Contents

Executive Summary ................................................................................................................................................ix

Products and Acknowledgments ...........................................................................................................................xi

GRI Products ................................................................................................................................................................................................. xi

Acknowledgments ....................................................................................................................................................................................... xi

Geologic Setting, History, and Significance ...........................................................................................................1

Park Establishment........................................................................................................................................................................................ 1

Physiographic Setting ................................................................................................................................................................................... 1

Connections between Geologic and Cultural Resources............................................................................................................................ 3

Geologic History............................................................................................................................................................................................ 4

Geologic Features and Processes, and Resource Management Issues ...............................................................11

Fluvial Features and Processes.................................................................................................................................................................... 11

Climate Change........................................................................................................................................................................................... 14

Brevard Zone ............................................................................................................................................................................................... 15

Cave Features and Processes ...................................................................................................................................................................... 15

Seismic Activity............................................................................................................................................................................................ 15

Mining and Minerals................................................................................................................................................................................... 16

Paleontological Resources.......................................................................................................................................................................... 17

Future Geologic Investigations .............................................................................................................................19

Geologic Map Data ................................................................................................................................................21

Geologic Maps............................................................................................................................................................................................. 21

Source Maps ................................................................................................................................................................................................ 21

GRI GIS Data ................................................................................................................................................................................................ 21

GRI Map Poster............................................................................................................................................................................................ 23

Use Constraints............................................................................................................................................................................................ 23

Literature Cited ......................................................................................................................................................25

Additional Resources .............................................................................................................................................27

Climate Change........................................................................................................................................................................................... 27

Geological Surveys and Societies ............................................................................................................................................................... 27

NPS Geology Interpretation and Education .............................................................................................................................................. 27

NPS Resource Management Guidance and Documents............................................................................................................................ 27

US Geological Survey (USGS) Reference Tools........................................................................................................................................... 27

Appendix A: Scoping Participants ........................................................................................................................29

Appendix B: Geologic Resource Laws, Regulations, and Policies.......................................................................31

v

Figures

Figure 1. Map of Horseshoe Bend National Military Park........................................................................................................................ xii

Figure 2. Physiographic provinces of Alabama. .......................................................................................................................................... 1

Figure 3. Paleogeographic maps of North America.................................................................................................................................... 4

Figure 4. Geologic time scale. ...................................................................................................................................................................... 5

Figure 5. Block diagrams of the geologic evolution of Horseshoe Bend National Military Park............................................................. 6

Figure 6. Normal faulting. ............................................................................................................................................................................ 7

Figure 7. Diagram showing the metamorphic pressure and temperature path of the Jacksons Gap and the Emuckfaw Groups 

(PCPZeg)......................................................................................................................................................................................................... 8

Figure 8. Photograph of Kowaliga Gneiss from Horseshoe Bend National Military Park........................................................................ 9

Figure 9. Photograph of a piece of the Jacksons Gap Group..................................................................................................................... 9

Figure 10. Diagram of a meandering river. ............................................................................................................................................... 10

Figure 11. Aerial photograph of the Tallapoosa River between Lake Harris and Lake Martin. ............................................................ 12

Figure 12. Photograph of stream terrace. ................................................................................................................................................. 14

Figure 13. Wilson’s Rock. ............................................................................................................................................................................ 15

Figure 14. Map of seismic hazard potential around Horseshoe Bend National Military Park. ............................................................ 16

Figure 15. Index map for the GRI GIS data of the park. ........................................................................................................................... 22

vii

Tables

Table 1. Stratigraphic table of GRI GIS (hobe_geology.mxd) bedrock map units. .................................................................................... 2

Table 2. GRI GIS data layers for Horseshoe Bend National Military Park. ............................................................................................... 22

2012 Scoping Meeting Participants ........................................................................................................................................................... 29

2018 Conference Call Participants ............................................................................................................................................................. 29

ix

Executive Summary

The Geologic Resources Inventory (GRI) provides geologic map data and pertinent geologic 

information to support resource management and science-informed decision making in more 

than 270 natural resource parks throughout the National Park System. The GRI is one of 12 

inventories—including geologic resources, vegetation mapping, natural resource bibliography, 

water resources, vertebrates and vascular plants, climate, base cartography, air quality, and soil 

resources (see https://www.nps.gov/im/inventories.htm)—funded by the National Park Service 

(NPS) Inventory and Monitoring Program. The Geologic Resources Division of the NPS Natural 

Resource Stewardship and Science Directorate administers the GRI.

This GRI report synthesizes discussions from a scoping meeting held in 2012 for Horseshoe 

Bend National Military Park (referred to as the “park” throughout this report) and a follow-up 

conference call in 2018 (see Appendix A). Chapters of this report discuss the park’s geologic setting 

and significance and draw connections between geologic and cultural resources, outline the geologic 

history leading to the present-day landscape, describe geologic issues facing resource managers, 

suggest future geologic investigations pertinent to the park’s resources, and provide information 

about the previously completed GRI map data. A poster (in pocket) illustrates these data.

The Battle of Horseshoe Bend in central eastern 

Alabama shaped United States history in the 19th 

century. More than 3,000 fighters under the command 

of Andrew Jackson defeated 1,000 Red Stick Creek 

warriors who had fortified themselves on the inside of 

a bend in the Tallapoosa River. The battle effectively 

ended the Red Stick resistance. Shortly after the battle 

on 27 March 1814, Jackson forced Creek leaders to 

cede 1.9 million acres (770,000 hectares) to the United 

States, including part of what is now Georgia and much 

of Alabama. Jackson’s success in the battle led to his 

promotion to major general and set his military career 

on a path that would lead to eventually becoming the 

seventh president of the United States. In the same 

way that the Battle of Horseshoe Bend would set 

the political stage for the next 200 years of American 

history, a geologic history of more than 300 million 

years shaped the landscape, setting the physical stage for 

the battle itself.

Deposition of the Emuckfaw sediments in the 

Cambrian–Ordovician Periods (541 million–444 million 

years ago), and continental collision and mountain 

building in the Early Mississippian Period (359 

million–323 million years ago) resulted in a landscape 

underlain by different types of metamorphic rocks. 

Some of these rocks are harder than others and this 

directly influences the path that the Tallapoosa River 

takes on its eventual course to the Gulf of Mexico. 

In the vicinity of the park, the river flows around the 

hardest rocks, the ridge-forming outcrops of Jacksons 

Gap Quartzite (map unit PCPZjgq); directly over other 

hard rock, the Jacksons Gap Group (PCPZjg); and takes 

a winding, meandering path through the softest rocks, 

the Kowaliga Gneiss (PCPZkg) and the Emuckfaw 

Group (PCPZeg). It is in one of these meander bends 

that the Creek peoples fortified their final defense 

against the advancing forces of Andrew Jackson, whose 

superior numbers were able to break through the 

barricade. The Tallapoosa River is incised into these 

bedrock units, cutting slowly deeper but not developing 

new meander bends or oxbow lakes, and preserving the 

Horseshoe Bend as a slice of US history.

This report is supported by a GRI-compiled map of 

the geology of Horseshoe Bend National Military Park 

that covers the park boundary and the surrounding 

area. The GRI map was compiled from a 2012 map 

at 1:24,000 scale completed by Kevin Jones, an M.S. 

student at Auburn University. The spatial distributions 

and unit descriptions of the map units informed 

a discussion of geologic features, processes, and 

associated resource management issues in Horseshoe 

Bend National Military Park. See Geologic Map Data 

chapter for more information about the map.

Geologic features, processes, and associated resources 

management issues identified during the GRI scoping 

meeting and follow-up conference call include the 

following:

● Fluvial Features and Processes. Fluvial features are 

formed by flowing water, either constructing or 

eroding landforms. The Tallapoosa River forms the 

defining feature of the park, the Horseshoe Bend. 

Other fluvial features in the park include perennial, 

ephemeral, and intermittent streams and stream 

terraces. Fluvial processes are ongoing and dynamic, 

and may also be management issues. At Horseshoe 
x

Bend National Military Park, potential management 

issues related to fluvial processes include erosion, 

mass wasting (gravity-driven transport of material), 

and flooding. Flood-level events cause erosion that 

threatens cultural resources along the Tallapoosa 

River. The vast majority of flooding in the park is a 

result of the Tallapoosa River’s artificial flow regime, 

which is controlled by an upstream hydroelectric 

dam.

● Climate Change. Climate change models for Alabama 

suggest hotter conditions with more extreme storms. 

Higher temperatures could impact the type and 

amount of vegetation that currently stabilizes the 

river banks and prevents erosion. Extreme storms 

may increase runoff and severity of floods.

● Brevard Zone. The Brevard zone is a regional 

geologic feature that borders the park to the 

southeast and is a key component of the geologic 

history of Horseshoe Bend. The Brevard zone 

represents regional-scale faulting associated 

with mountain building, and is characterized by 

two rock types within the Jacksons Gap Group, 

undifferentiated phyllites and schists (PCPZjg) and a 

prominent ridge-forming quartzite (PCPZjgq).

● Cave Features and Processes. Caves typically 

form as part of a karst landscape where soluble 

rock is removed by flowing water. The bedrock in 

Horseshoe Bend National Military Park is nonsoluble and does not host caves in the traditional 

sense. However, Wilson’s Rock, an overhang of 

unknown cultural significance does fit under the 

broader heading of a cave feature.

● Seismic Activity. The park has a history of felt 

earthquakes, although is not considered to be at high 

risk of strong earthquakes. Seismicity could impact 

park resources, particularly if movement along faults 

led to changes in groundwater flows, which in turn 

led to a loss of water in wells.

● Mining and Minerals. The Brevard zone has 

historically been the site of minor gold production, 

although within the park no current plans for 

commercial mining and minimal recreational interest 

exist. A gravel pit to supply road material is one of 

two Abandoned Mineral Lands (AML) features in 

the park, neither requiring mitigation.

● Paleontological Resources. Fossils are evidence of 

life preserved in a geologic context. Fossils have not 

been documented in the park, but may exist in an 

archeological context. Fossils are non-renewable 

and are subject to science-informed inventory, 

monitoring, protection, and interpretation as 

outlined by the 2009 Paleontological Resources 

Preservation Act.

Appendix A of this report provides a list of people 

who participated in the scoping meeting for the park 

in 2012, as well as those who participated in a followup conference call in 2018. The list serves as a legacy 

document and reflects participants’ affiliations and 

positions at the time of scoping and the conference call.

Appendix B of this report lists laws, regulation, and NPS 

policies that specifically apply to geologic resources in 

the National Park System. The NPS Geologic Resources 

Division can provide policy assistance and technical 

expertise, regarding the park’s geologic resources.
xi

Products and Acknowledgments

The NPS Geologic Resources Division partners with the Colorado State University, Department 

of Geosciences, to produce GRI products. The US Geological Survey, state geological surveys, local 

museums, and/or universities developed the source maps and reviewed GRI content. This chapter 

describes GRI products and acknowledges contributors to this report.

GRI Products

The GRI team undertakes three tasks for each park in 

the Inventory and Monitoring program: (1) conduct a 

scoping meeting and provide a summary document, 

(2) provide digital geologic map data in a geographic 

information system (GIS) format, and (3) provide a GRI 

report (this document). These products are designed 

and written for nongeoscientists.

Scoping meetings bring together park staff and geologic 

experts to review and assess available geologic maps, 

develop a geologic mapping plan, and discuss geologic 

features, processes, and resource management issues 

that should be addressed in the GRI report. Following 

the scoping meeting, the GRI map team converts the 

geologic maps identified in the mapping plan to GIS 

data in accordance with the GRI data model. After the 

map is completed, the GRI report team uses these data, 

as well as the scoping summary and additional research, 

to prepare the GRI report. The GRI team conducts no 

new field work in association with their products.

The compilation and use of natural resource 

information by park managers is called for in the 

1998 National Parks Omnibus Management Act (§ 

204), National Park Service Management Policies 

2006, and the Natural Resources Inventory and 

Monitoring Guideline (NPS-75). The “Additional 

Resources” chapter and Appendix B provide links to 

these and other resource management documents and 

information.

Additional information regarding the GRI, including 

contact information, is available at http://go.nps.gov/gri.

Acknowledgments

The GRI team thanks the participants of the 2012 

scoping meeting and 2018 conference call (see 

Appendix A) for their assistance with this inventory. 

Thanks very much to Kevin Jones, who produced 

the source map (Jones 2012) for the GRI GIS data of 

the park. Thank you to the reviewers of this report, 

especially Jake McDonald of the University of 

North Georgia for his comments on fluvial features 

and processes; and to Mark Steltenpohl of Auburn 

University, and Dane S. VanDervoort and John P. 

Whitmore of the Geological Survey of Alabama for the 

helpful review of the local and regional geology. Thanks 

to Stacy Speas of Horseshoe Bend National Military 

Park for her comments on the cultural and historical 

information included in this report. And a big thank 

you to Trista Thornberry-Ehrlich (Colorado State 

University) for creating many of the graphics used in 

this report.

Review

Jason Kenworthy (NPS Geologic Resources Division)

Jacob M. Bateman McDonald (University of North 

Georgia)

Mark Steltenpohl (Auburn University)

Dane S. VanDervoort (Geological Survey of Alabama)

John P. Whitmore (Geological Survey of Alabama)

Editing

Katie KellerLynn (Colorado State University)

Report Formatting and Distribution

Chelsea Bitting (National Park Service)

Source Maps

Kevin Jones (Auburn University)

GRI GIS Data Production

Georgia Hybels (Colorado State University)

Stephanie O’Meara (Colorado State University)

GRI Map Poster Design

Dylan Rolley (Colorado State University)

GRI Map Poster Review and Editing

Michael Barthelmes (Colorado State University)

Georgia Hybels (Colorado State University)

Rebecca Port (National Park Service)
xii

Figure 1. Map of Horseshoe Bend National Military Park.

The Tallapoosa River enters the park boundary on the northeast side and exists at the northwest. A 

walking tour of the park includes stops at sites important to the history of the park. National Park Service 

Map, available at https://www.nps.gov/carto/hfc/media/HOBEmap1.jpg. 
1

Geologic Setting, History, and Significance

This chapter describes the regional geologic setting and history of Horseshoe Bend National Military 

Park and summarizes connections among geologic resources, other park resources, and park stories.

Park Establishment

Horseshoe Bend National Military Park (Figure 1) 

was established by presidential proclamation 3308 by 

Dwight D. Eisenhower on 11 August 1959. The park 

was established with the stated purpose to “preserve 

and protect the site of the last major engagement of the 

Creek War (1813-1814). The park interprets the events 

of the battle in the larger context of the War of 1812, 

as well as their impacts on the Creek people and the 

development of the United States.” The park gets its 

name from a bend in the Tallapoosa River where the 

battle took place on 27 March 1814, between US forces 

under the command of Andrew Jackson and Red Stick 

warriors, who had built fortifications on the inside bend 

of the river.

The park is distinctive in that it is the only National 

Park Service unit east of the Mississippi River to protect 

the site of a battle between an American Indian tribe 

and the US Military (National Park Service 2014). In 

addition to the site of the battle, the park also protects 

two Creek habitation sites, Nuyaka and Tohopeka. 

Nuyaka was burned by Georgia militia three months 

before the battle, and its inhabitants retreated to 

Tohopeka along with refugees from five other destroyed 

Creek towns where the Creek warriors and families 

prepared for the Battle of Horseshoe Bend.

Physiographic Setting

The park is situated in the southernmost extent of the 

Piedmont physiographic province (Figure 2), which 

spans roughly parallel to the Appalachian Mountains 

from Alabama to New York. The province consists of 

weathered metamorphosed sedimentary and igneous 

rocks; in the park, the igneous rocks have also been 

metamorphosed to gneiss (PCPZkg). The topography 

of the area is a result of the resistance to weathering 

of the different types of rocks. Softer rocks are eroded 

away and harder rocks remain to form ridges, including 

Cherokee Ridge along the southeast border of the 

park (see poster, in pocket). The paths of rivers are 

also controlled by the bedrock, with rivers more likely 

to take a meandering path through softer rock and to 

follow a more direct route over harder rock. This can be 

observed in the bend that gives the park its name.

There are two distinct lithologies in the park: the 

Emuckfaw Group (PCPZeg), a metasedimentary schist 

unit with metamorphosed igneous intrusions (the 

Kowaliga Gneiss, map unit PCPZkg); and the Jacksons

Figure 2. Physiographic provinces of Alabama.

Horseshoe Bend National Military Park (marked 

on map with a green star) is within the Piedmont 

physiographic province. Graphic by author, aerial 

imagery from ArcMap (accessed 4 April 2020). 

Gap Group, a gradational tangle of metasedimentary 

schist and phyllite (PCPZjg) with ridge forming 

quartzites (PCPZjgq). The Emuckfaw Group is separated 

from the Waresville Schist (PCPZws) by the Brevard fault 

zone, which is characterized by sheared and faulted 

rocks of the Jacksons Gap Group. The fault zone is 

bounded on the north, and structurally lower, side by 

the Abanda fault; and on the south, and structurally 

highest, side by the Katy Creek fault. See Table 1 for 

detailed descriptions of the GRI GIS map units.
2

Table 1. Stratigraphic table of GRI GIS (hobe_geology.mxd) bedrock map units.

amphibolite. A coarse-grained metamorphic rock made up primarily of amphibole (silicate) minerals and plagioclase 

feldspar. Amphibolite facies is a high temperature, high pressure metamorphic facies under which amphibolite is 

produced.

biotite. A dark-colored, shiny silicate mineral (silicon + oxygen) of the mica group composed of magnesium and/or 

iron, K(Mg,Fe)Si3O10(OH)2; characterized by perfect cleavage, readily splitting into thin sheets.

chlorite. A phyllosilicate mineral often formed in the early stages of metamorphism. Commonly greenish, although 

can appear as yellow, red, or white.

epidote. A common metamorphic minerals with the chemical formula Ca2(Al,Fe)2(SiO4)

3

(OH)

euhedral. A grain bounded by perfect crystal faces; well-formed.

felsic. Derived from feldspar + silica to describe an igneous rock having abundant light-colored minerals such as 

quartz, feldspars, or muscovite; also, describes those minerals.

foliation. A metamorphic texture of repeated layering caused by shearing or differential stress.

garnet. Refers to a group of silicate minerals sharing general physical characteristics but differing in chemical 

composition.

greenschist facies. A low-temperature, moderate pressure (typically 300-450°C, 2-10 kilobars) set of metamorphic 

conditions. Minerals produced include chlorite, actinolite, and albite. Chlorite is often a green mineral, which gives 

the facies and rock type its name.

K-feldspar (k-spar) or potassium feldspar. A feldspar mineral rich in potassium such as orthoclase, microcline, and 

sanidine.

lineation. A metamorphic texture of linear features. The one-dimensional counterpart of foliation.

mafic. Derived from magnesium + ferric (Fe is the chemical symbol for iron) to describe an igneous rock having 

abundant dark-colored, magnesium- or iron-rich minerals such as biotite, pyroxene, or olivine; also, describes those 

minerals.

metamorphic rock. Any rock derived from preexisting rocks that was altered in response to marked changes in 

temperature, pressure, shearing stress, and chemical environment. One of the three main classes of rock—igneous, 

metamorphic, and sedimentary.

micaceous. Consisting of, containing, or pertaining to mica; also, resembling mica, for example, a “micaceous 

mineral” capable of being easily split into thin sheets.

microcline. A potassium-rich alkali feldspar occurring in igneous rocks (KAlSi3

O8).

monzonite. An igneous intrusive rock of approximately equal parts plagioclase and alkali feldspar. If a monzonite 

contains more than 5% quartz it is called “quartz monzonite.”

muscovite. A light-colored silicate (silicon + oxygen) mineral of the mica group, KAl3Si3O10(OH)2, characterized by 

perfect cleavage in one direction and the ability to split into thin, clear sheets.

oxidize. The process of combining with oxygen.

phenocryst. A coarse-grained crystal in a porphyritic igneous rock.

plagioclase. A silicate (silicon + oxygen) mineral of the feldspar group that contains both sodium and calcium ions 

that freely substitute for one another; characterized by striations (parallel lines) in hand specimens. 

porphyroblast. A large grain occurring in smaller groundmass in a metamorphic rock.

quartz. Silicon dioxide, SiO2. The only silicate (silicon + oxygen) mineral consisting entirely of silicon and oxygen. 

Synonymous with “crystalline silica.”

saprolite. A chemically weathered rock occurring in humid or temperate climates.

schist. A medium- to coarse-grained, strongly foliated, metamorphic rock with eminently visible mineral grains, 

particularly mica, which are arranged parallel, imparting a distinctive sheen or “schistosity” to the rock.

sericite. A fine-grained and fibrous variety of muscovite. Common in schist or hydrothermally altered rocks.

subhedral. A grain partly bounded by crystal faces; intermediate between euhedral and anhedral.

Geologic Map Unit Map Unit Description

Waresville Schist

(PCPZws)

Felsic schist with quartz, biotite, k-spar, and sericite in saprolitized light-tan-to-white outcrops with <1 

cm (<0.3 in) k-spar porphyroblasts.
3

Geologic Map Unit Map Unit Description

Katy Creek fault Katy Creek fault

Jacksons Gap Group 

quartzite

(PCPZjgq)

Ridge-forming erosion-resistant micaceous quartzite within the Jacksons Gap Group. Accessory 

minerals include epidote, biotite, graphite, and local garnets. Forms Cherokee Ridge in the park.

Jacksons Gap Group

(PCPZjg)

Up to four mappable unites have been observed in the Jacksons Gap Group but they are a complex 

tangle of gradational contacts that can singularly be best described as a graphitic quartz schist. A 

prograde mineral assemblage includes muscovite, biotite, garnet, and quartz; minerals indicative of 

greenschist facies metamorphism. At the structural top of the Jacksons Gap Group, lower amphibolite 

conditions are documented, suggesting an inverted thermal gradient likely caused by “down heating” 

from the Waresville Schist/Dadeville Complex.

The Jacksons Gap Group is dominated by a retrograde overprint where biotite and muscovite are 

replaced by chlorite and sericite, respectively.

Abanda fault Abanda fault

Kowaliga Gneiss

(PCPZkg)

Quartz monzonite with well-foliated and lineated quartz, k-spar, plagioclase, and biotite. Schistosity 

is defined by biotite, muscovite, and quartz draped around subhedral microcline (Figure 8). Exists as a 

sapprolite in outcrop. Bedrock unit beneath the Horseshoe Bend.

Emuckfaw Group

(PCPZeg)

Amphibolite facies, coarse-grained muscovite schist with euhedral garnets up to 1 cm (0.3 in) in 

diameter where composition allows. Exposures weather to a deep red-maroon, garnets oxidized to 

dark brown.

Much of the geology and topography of the park 

reflects a series of orogenies, or mountain building 

events, that took place more than 300 million years 

ago. Before this upheaval, about 500 million years 

ago (Figure 3a), the area was an environment much 

like today’s Gulf of Mexico seaboard with sediment 

being deposited along a passive continental margin 

(Barineau et al. 2015). Around 350 million years ago 

(Figure 3b), pieces of continental crust and island arc 

called terranes were colliding with and accreting to 

what is now the eastern United States. In the park, this 

produced deformation (in the form of thrust faults) and 

metamorphism as the southern Appalachian Mountains 

formed.

Connections between Geologic and Cultural 

Resources

The namesake bend in the Tallapoosa River is an 

obvious geologic connection to the park’s cultural 

resources. The park’s resource stewardship strategy 

(RSS) identifies the battlefield, the Tallapoosa River, 

and the Tohopeka and Nuyaka Village sites as priority 

resources “necessary to maintain the park’s purpose 

and significance.” The path of the Tallapoosa River in 

the park is a direct result of the underlying geology, see 

the “Geologic History” chapter for further discussion.

The Nuyaka Village was established in 1777 and offers 

archeological evidence of Creek life before the onset of 

the Creek War. The Tohopeka Village was established as 

a refuge for Creeks fleeing the Creek War in 1813 and 

was destroyed by US troops in 1814 during the Battle 

of Horseshoe Bend. Both village sites are important 

locations for archeologic and ethnographic study of 

the Creek people (National Park Service 2017). The 

battlefield itself is the principal resource of the park 

and includes the site of the wood barricade built to 

protect the Tohopeka Village. This log barricade was 

constructed across the narrowest part of the neck of the 

meander bend (Figure 1).

Rivers, and meander bends in particular, have been 

important strategic features in many historic battles 

(Henderson 2000). In the case of the Battle of 

Horseshoe Bend, the river, combined with the log 

barricade, initially protected the Red Sticks because 

Jackson’s artillery fire had little effect on the barricade. 

Cherokee warriors allied with Jackson seized an 

opportunity to swim across the Tallapoosa, steal Creek 

canoes, ferry additional Cherokee to the village and set 

it on fire. This diversion allowed the 39th Infantry under 

General Andrew Jackson to charge over the barricade. 

During the battle, more than 800 Red Sticks died; 72 

Americans and Indian allies were also killed. The course 

of the Tallapoosa River as influenced by geological 

factors that created the horseshoe bend in the river (see 

“Tallapoosa River”), is undeniably critical to the cultural 

history of the Creek War and the Battle of Horseshoe 

Bend.

Table 1, continued. Stratigraphic table of GRI GIS (hobe_geology.mxd) bedrock map units.
4

Geologic History

Much of the “action” of the geologic history of the 

park is related to events that took place between 500 

million and 300 million years ago during the early- to 

mid-Paleozoic Era (Figure 4) and is associated with the 

formation of the Appalachian Mountains. As with the 

Appalachians, the area has been largely tectonically 

inactive for the past 300 million years; the mountain 

formations have slowly but thoroughly weathered to 

produce a surface of minimal relief.

570 million to 444 million years ago (Precambrian 

to Paleozoic [Cambrian/Ordovician Periods]) 

Continental Rifting and Back-Arc Sedimentation

Around 570 million years ago, the supercontinent 

Rodinia was rifting apart to form continental 

landmasses, including the precursor to North America: 

Laurentia (Thomas 2006; Barineau et al. 2015). Rifting 

also created the Iapetus Ocean, a precursor to today’s 

Atlantic Ocean. During the Early Cambrian Period, 

about 540 million years ago, the Ouachita rift opened, 

separating a block of land from Laurentia (Figure 5a). 

As this “microcontinent” drifted across the Iapetus 

Ocean (to eventually collide with the supercontinent 

Gondwana), it left behind an area of thin, stretched 

crust characteristic of continental rift zones. Geologists 

theorize that an extensional fault associated with this 

crustal thinning initiated a minor, westward-dipping 

subduction zone as the cold, dense oceanic crust of the 

Iapetus Ocean plunged into the mantle (McClellan et al. 

2007; Tull et al. 2007, 2012; Hawkins 2013) (Figure 5b).

Subduction zones, whatever their size, create a distinct 

set of depositional environments where rocks are 

created. As a “downgoing slab” of oceanic crust is 

subducted into the hot mantle it begins to melt and the 

hot magma rises to the surface where some is erupted 

as lava. This creates a line of volcanic islands between 

the subduction trench and the continental mainland; 

the space between this “volcanic arc” and the mainland 

is known as a “back-arc basin,” and is characterized 

by deposition of sediments with both continental and 

volcanic origins. Additionally, some of the magma rising

Figure 3. Paleogeographic maps of North America.

The green star indicates the approximate position of Horseshoe Bed National Military Park. In A, the 

sedimentary material of the Emuckfaw Group (PCPZeg) is being deposited in the Iapetus Sea. In B, 

continents are colliding and causing metamorphism and deformation. Basemaps are "North American Key 

Time Slices" © 2013 Colorado Plateau Geosystems, Inc; used under license. Refer to http://deeptimemaps.

com/ for additional information.
5

Figure 4. Geologic time scale.

The divisions of the geologic time scale are organized stratigraphically, with the oldest divisions at the 

bottom and the youngest at the top. GRI map abbreviations for each time division are in parentheses. 

Rocks and deposits of interest for the park are from the Precambrian (X and Y), Cretaceous Period (K), 

Tertiary (T), and Quaternary Period (Q) (see table 1). Compass directions in parentheses indicate the 

regional locations of events. Boundary ages are millions of years ago (mya). NPS graphic using dates from 

the International Commission on Stratigraphy (http://www.stratigraphy.org/index.php/ics-chart-timescale; 

accessed 15 August 2018).
6

to the surface does not erupt but becomes emplaced in 

these sedimentary rocks as plutons.

In the case of the geology of the park, the sedimentary 

rocks that were later metamorphosed into the 

Emuckfaw Group and the Jacksons Gap Group may 

have been deposited in this back-arc environment 

(Figure 5c) (Tull et al. 2012, 2014). The igneous 

(plutonic) rocks of the park and the surrounding 

area were likely emplaced this way. These include the 

Kowaliga Gneiss (included in GRI GIS data, PCPZkg) 

Figure 5. Block diagrams of the geologic evolution of Horseshoe Bend National Military Park.

Block diagram show stages in the geologic evolution of Horseshoe Bend over the past 570 million years, 

including crustal extension (A, B); subduction initiation (C); thrust faulting and prograde metamorphism 

(D, E); normal faulting and retrograde metamorphism (F, G); and the present-day park with the path of the 

Tallapoosa River shaped by the underlying rocks (H). Graphic by Trista Thornberry-Ehrlich (Colorado State 

University).
7

and the Zana Granite (not included in GRI GIS data). 

Crystallization ages (the time that has passed since a 

melt solidified into rock) for the Kowaliga Gneiss give 

a value of 441 million ± 6 million years ago (Hawkins 

2013; Tull et al. 2014). Because the magma could not 

have intruded into the sedimentary rocks before they 

existed, the Emuckfaw Group must be older than this. 

This principle is known in geology as the law of crosscutting relationships.

350 million years ago (Devonian Period): Neo 

Acadian Orogeny, including Thrust Faulting and 

Metamorphism

Beginning in the Cambrian Period and continuing 

into the Devonian Period, large westward-dipping 

subduction began closing the Iapetus Ocean, and 

islands and microcontinents were pulled in to 

collide with the eastern margin of Laurentia. On the 

continental margin, these collisions pushed the crust up 

to form the towering Appalachian Mountains reaching 

heights that may have rivaled today’s Himalayas. Farther 

inland, in the area that would become the park, the 

compression of the crust deformed the sedimentary 

rock layers that had been deposited in the back-arc 

basin. A series of thrust faults (Figure 5d) developed 

as rocks were pushed on top of one another. In the 

GRI GIS data, the Waresville Schist (of the Dadeville 

Complex) was thrust on top of the Emuckfaw Group. 

Separating these two units is the Brevard fault zone, 

characterized by rocks of the Jacksons Gap Group 

(Figure 5e).

Thrust faulting placed rock units deep beneath other 

rocks, subjecting them to intense temperatures and 

pressures. These conditions caused the mineral 

assemblages in the rocks to metamorphose into new 

minerals. Because different pressure and temperature 

conditions cause different minerals to grow, geologists 

name different types of metamorphic rocks according 

to the mineral assemblages that form (see Figure 7). 

The Emuckfaw Group was metamorphosed at lower/

middle amphibolite facies. The Jacksons Gap Group 

experienced an inverted thermal gradient, as the 

thrusted Dadeville Complex heated it from above 

(Steltenpohl and Singleton 2014). Accordingly, the 

Jacksons Gap Group shows a range of metamorphic 

mineral assemblages, from lower greenschist to lower/

middle amphibolite facies (amphibolite facies occurs 

at higher temperatures and pressures, or a higher 

metamorphic grade, than greenschist facies).

330 million years ago (Carboniferous Period): Early 

Alleghenian Orogeny, including Reactivation of 

Faults and Retrograde Metamorphism

During a break in continental accretion, the compressed 

crust relaxed and extended (Figure 6). This coincided 

with the formation of the Tallassee Synform, a massive, 

landscape-scale feature. The Emuckfaw Group and 

Brevard fault zone form the western limb of this 

structure; the Dadeville Complex forms the core.

As the rocks relaxed from their compressed conditions 

and erosion removed some of the overlying units, 

retrograde metamorphism took place (Bobyarchick 

et al 1988; Steltenpohl and Singleton 2014) (Figure 

5f). This occurs when rocks move from the highest 

temperature/pressure conditions of their metamorphic 

path and some of the minerals become unstable, 

metamorphosing into lower grade minerals (Figure 

7). This is often an incomplete metamorphism, so 

the rocks show minerals formed in both the original 

metamorphic event (prograde) and minerals formed 

in subsequent metamorphism (retrograde). Because 

retrograde metamorphism is often a result of rock units 

being exhumed, the retrograde overprint is almost 

always at a lower metamorphic grade than the prograde 

assemblage.

In the park, the Emuckfaw Group experienced a 

middle/upper greenschist overprint, causing the mineral 

hornblende to be replaced by actinolite and chlorite 

(Steltenpohl and Singleton 2014). In the Jacksons Gap 

Group, which is dominated by the retrograde overprint, 

biotite and muscovite were replaced by chlorite and

Figure 6. Normal faulting.

Block diagram showing a normal fault. During 

crustal extension, rocks will slide along existing 

fault lines or fractures. Blocks will drop down along 

normal faults as a result of extension. Diagram 

by Trista Thornberry-Ehrlich (Colorado State 

University).
8

sericite respectively. Another thing geologists look 

at to determine the metamorphic history of a rock is 

the orientation of the minerals within the rock. The 

metamorphism related to thrust faulting physically 

stresses, or strains, the mineral grains, causing them 

to align. This texture in a rock, where platy minerals 

align, is known as schistosity, and can be visible in hand 

sample and/or microscopically (Figure 8). In the case of 

the retrograde overprint, the chloritoid minerals of the 

Jacksons Gap Group are not aligned, but are randomly 

oriented, suggesting that the conditions under which 

they formed did not include physical stress (Figure 9).

Similar to the rocks within the park, the Waresville 

Schist (PCPZws in the GRI GIS map data, but not 

mapped within the boundaries of the park) was also 

subjected to a retrograde overprint at upper greenschist 

to lower amphibolite facies conditions.

Although there were no additional metamorphic 

events, the rocks underwent two further deformations 

(Steltenpohl and Singleton 2014). In the first, the 

Abanda fault (the structurally lowermost boundary 

of the Brevard fault zone) was reactivated as an 

oblique normal fault (Figure 5g). In this movement, 

the overlying rock unit moved in a top-down-to-theeast direction. This juxtaposed rock units of different 

metamorphic grade, whose contacts had previously 

been gradational. Finally, as the rocks had cooled, brittle 

faults developed along the Abanda fault. These faults are 

characterized by cataclasite, or a rock type that develops 

along faults as brittle rocks are fragmented as they slide 

along faults. Much of the cataclasite along the Abanda 

fault is related to the Kowaliga Gneiss, which is harder 

than the Emuckfaw Group. This brittle movement 

may have been related to the breakup of Pangea in the 

Mesozoic Era (175 million–140 million years ago).

The Last 66 million years (Cenozoic Era): 

Development of the Tallapoosa River

In the time since the Paleozoic Era and the formation of 

the Appalachian Mountains, the area has been largely 

tectonically inactive. Today, the eastern margin of 

North America is a passive margin with no subduction 

or collision occurring. The last large-scale tectonic 

event to affect the Appalachians was the post-orogenic 

collapse of the mountain chain following the Mesozoic 

rifting of Pangea (approximately 170 million years ago). 

Since then, the most significant forces acting upon the 

landscape have been erosional, slowly weathering and 

transporting away the relief features of the landscape. 

Over millions of years this has transformed 

Figure 7. Diagram showing the metamorphic pressure and temperature path of the Jacksons Gap and the 

Emuckfaw Groups (PCPZeg).

The diagram shows the different rock types (based on mineral assemblages) that are created at different 

temperatures and pressures at depth. The dashed line shows the path of the rock unit as it reached 

prograde metamorphic conditions (M1) and retrograde metamorphic conditions (M2). In panel A, the 

Jacksons Gap Group (PCPZjg) has a bar indicating a range of temperature at M1 as part of the unit 

was heated from above by the Waresville Schist. Both units experienced greenschist facies retrograde 

overprinting at M2. NPS graphic by Amanda Lanik after Winter (2001), with P-T paths by the author.
9

the Appalachian Mountains from a range to rival the 

Himalayas to their present, gently rolling form.

Like the rocks of the Appalachian Mountains, the rocks 

of the park have been similarly eroded. The different 

types of metamorphic rock in the park have different 

hardnesses, or resistance to erosion. Therefore, softer 

rocks such as the Emuckfaw Group (PCPZeg) and the 

Kowaliga Gneiss (PCPZkg) are preferentially eroded 

while the harder rocks like the Jacksons Gap Group 

quartzite (PCPZjgq) remain to form surface relief such as 

Cherokee Ridge, on the southeastern boundary of the 

park.

The rocks’ resistance to erosion has also affected the 

flow path of the Tallapoosa River (Figure 5h). The 

Tallapoosa is a meandering river, meaning that it winds 

back and forth across its relatively level floodplain 

(Figure 10), following the path of least resistance as 

it makes its way from near Atlanta, Georgia, to its 

confluence with the Coosa River near Montgomery, 

Alabama, to form the Alabama River. The path of least 

resistance is heavily influenced by the rock type over 

which the river flows. In the park, the Tallapoosa River 

takes a more direct route over the harder rocks of the 

Jacksons Gap Group (see poster, in pocket). Conversely, 

over the softer Kowaliga Gneiss, the river takes a 

meandering path. This includes the meander that 

Figure 8. Photograph of Kowaliga Gneiss from Horseshoe Bend National Military Park.

Notations show direction of foliation (black lines) of biotite (Bt), muscovite (Ms), and quartz (Qtz) draped 

around microcline (Mc) crystals. Finger ring for scale. NPS photograph by Rebecca Port, notations by 

author.

Figure 9. Photograph of a piece of the Jacksons Gap 

Group.

Notice the minerals of the Jacksons Gap Group 

(PCPZjg), with a quartzite inclusion (PCPZjgq, 

in box), visible in the picture are not foliated 

(compare to figure 8). Much of the prograde 

mineral assemblage was replaced during retrograde 

metamorphism, which was not accompanied by 

physical strain to produce foliation. Pen for scale. 

Photograph by Katie KellerLynn (Colorado State 

University).
10

forms the horseshoe shaped bend for which the park is 

named. This feature is what is known as an entrenched 

meander, meaning that the river has cut through the 

sediment of the floodplain and into the bedrock, 

and is unlikely to change its morphology. In contrast, 

the meander just upstream of the bridge (Figure 1) is 

actively being cut off and may eventually become an 

oxbow lake (Figure 10).

Figure 10. Diagram of a meandering river.

Series of four block diagrams showing the 

evolution of a meandering stream. The “neck” of 

the meander bend becomes narrower until a flood 

causes the river to close off the neck. Sediment 

slowly plugs the up- and down-stream sides of the 

cutoff meander, creating an oxbow lake to the side 

of the new flow path. Because the Tallapoosa River 

is incised into the bedrock, the Horseshoe Bend is 

stuck at the second stage and is unlikely to “close 

off” the neck of the bend and form an oxbow lake 

(in grey). NPS graphic by Phil Reiker.
11

Geologic Features and Processes, and Resource Management 

Issues

Some geologic features, processes, or human activities may require management for human safety, 

protection of infrastructure, and preservation of natural and cultural resources.

The NPS Geologic Resources Division (GRD) (see 

http://go.nps.gov/grd) can provide technical and policy 

support for geologic resource management issues 

or direct park managers to other resources, such as 

for climate change, monitoring, interpretation, and 

resource education relating to the park’s geologic 

resources (discussed below). GRD programs and 

staff focus on three areas of emphasis: (1) geologic 

heritage, which would address the Brevard fault zone 

and paleontological resources; (2) active processes 

and hazards, which would address fluvial features and 

processes, mass wasting, cave features and processes, 

and seismic hazards; and (3) energy and minerals 

management, which would address mining operations 

(discussed below).

Resource managers may find Geological Monitoring

(Young and Norby 2009) useful for addressing 

geologic resource management issues. The manual, 

which is available online at http://go.nps.gov/

geomonitoring, provides guidance for monitoring vital 

signs (measurable parameters of the overall condition 

of natural resources). Each chapter of Geological 

Monitoring covers a different geologic resource and 

includes detailed recommendations for resource 

managers, suggested methods of monitoring, and 

case studies. Where applicable, those chapters are 

highlighted in the following discussion. Notably, the 

Southeast Coast Network is currently monitoring 

wadeable streams, a vital sign related to the geologic 

resources in the park (see https://www.nps.gov/im/secn/

wadeable-streams.htm).

Since scoping in 2012, the National Park Service 

completed a foundation document for the park 

(National Park Service 2014) and a resource 

stewardship strategy (National Park Service 2017). 

Because these documents are a primary source of 

information for resource management within the park, 

they were used in preparation of this report to draw 

connections between geologic features and “core 

components” such as “fundamental resources and 

values” and “other important resources and values.”

In 2018, a follow-up conference call with park and 

network staff, an Alabama Geological Survey (AGS) 

geologist, and GRI team members (see Appendix 

A) verified the present-day pertinence of the issues 

identified in 2012. In addition, the call helped to update 

the list of geologic resource management issues and 

guide research of this report.

The following updated list of geologic features and 

processes, and resource management issues is based on 

the 2012 scoping summary, 2014 foundation document, 

2017 resource stewardship strategy, 2018 conference 

call discussion, and reviewers’ comments. The issues are 

ordered based on management priority.

● Fluvial Features and Processes

● Erosion and Mass Wasting

● Climate change

● Seismic Activity

● Cave Features and Processes

● Brevard Zone

● Mining and Minerals

● Paleontological Resources

Fluvial Features and Processes

Fluvial features and processes are related to flowing 

water, such as rivers and streams. Fluvial features 

in Horseshoe Bend National Military Park include 

ephemeral and intermittent streams, gullies, stream 

terraces and the namesake bend, an entrenched 

meander. Fluvial processes in the park include flooding 

and erosion, which can lead to mass wasting. The 

Tallapoosa River is the defining feature of the park, 

but included in the park boundary are at least three 

unnamed perennial streams, one of which is being 

monitored for vital signs by the Southeastern Coastal 

Region (McDonald 2019). For a thorough description 

of perennial and ephemeral streams in the park, see 

Wadeable Stream Suitability Assessment for Long-Term 

Monitoring: Horseshoe Bend National Military Park

(McDonald 2019).

Tallapoosa River

The Tallapoosa River flows 426 km (265 mi) from the 

Appalachian Mountains in Georgia southwest into 

Alabama where it joins the Coosa River to form the 

Alabama River. Along its course, the Tallapoosa River 

is dammed in four locations; Horseshoe Bend National 

Military Park is located between the Harris Dam (68 km 

[42 mi] upstream of the park) and the Martin Dam (53 

km [33 mi] downstream of the park) (Figure 11). 
12

Figure 11. Aerial photograph of the Tallapoosa River between Lake Harris and Lake Martin.

The Tallapoosa River is dammed upstream (Lake Harris) and downstream (Lake Martin) of Horseshoe 

Bend National Military Park (park boundary in green). The upstream Harris Dam is the primary factor 

in regulating the flow regime of the Tallapoosa River in Horseshoe Bend. Aerial imagery from ArcMap 

(accessed 23 April 2020).
13

The Harris Dam is the main driver of flow regime (via 

impoundment of water behind the dam or release from 

the reservoir) for the Tallapoosa River in the park. Park 

staff have a working relationship with the hydroelectric 

company that manages the dam (Alabama Power), and 

provided input to the ongoing relicensing process for 

the Harris Dam (Stacy Speas, Horseshoe Bend National 

Military Park, lead ranger, GRI conference call, 27 

November 2018). For a timeline of human activities 

affecting streams monitored by the Southeastern 

Coastal Network (SECN), see Monitoring Wadeable 

Stream Habitat Conditions in Southeast Coast Network 

Parks Protocol Narrative (McDonald et al. 2018). The 

segment of the Tallapoosa River that meanders through 

the park is approximately 6 km (3.7 mi).

Horseshoe Bend

The namesake bend in the river is perhaps the park’s 

most significant feature, fluvial or otherwise. The 

Tallapoosa River is a meandering stream, meaning that 

the river is composed of a single channel that winds its 

way snakelike across the landscape, so that the channel 

length (distance the stream flows) is substantially 

greater than valley length (“as the crow flies”). As water 

flows through a river channel, its velocity is greater at 

the outside of its curves. This increased velocity leads 

to erosion at the outer edge of a bend and the formation 

of a “cutbank.” Low velocities on the inside curve of a 

river commonly leads to deposition at the inner edge 

or the formation of a “point bar” (Figure 10). Erosion 

also occurs at the downstream side of the stream 

channel so that in addition to moving laterally, bends 

will migrate downstream over time. A time-lapsed video 

of a meandering stream would look like a large snake 

moving downstream.

Another feature of meandering streams is the formation 

of oxbow lakes (Figure 10). The bends of a meander 

will migrate, via flooding and erosion, closer and closer, 

until only a narrow neck of land separates them. During 

floods, or other high-flow events, the river may breach 

the neck of land and the flow will bypass the meander 

entirely, leaving a bend-shaped body of water known as 

an oxbow lake. These oxbow lakes may subsequently be 

filled in with sediments that wash or blow in over land. 

The formation and filling in of oxbow lakes occur when 

the river is flowing over and through a floodplain, and 

the recently deposited sediments are easily reworked by 

the fluvial processes.

Horseshoe Bend is an entrenched meander, that is, 

the river has cut through the surficial deposits and 

into bedrock. Because bedrock is harder and more 

erosion resistant than the loose, surficial sediments 

of a floodplain, once a river becomes entrenched it is 

unlikely to develop new meanders or oxbow lakes. For 

a dramatic example, a truly catastrophic flood would be 

required to cause the Colorado River to jump its banks 

and turn the Horseshoe Bend of the Grand Canyon into 

the Grand Oxbow Lake. In the same way, the Tallapoosa 

River is incised into the metamorphic bedrock and is 

similarly unlikely to form a “Horseshoe Lake” at the 

park.

The underlying geology also has had an effect on 

the morphology of the Tallapoosa River in the park. 

Most notable in the GRI GIS data is the presence 

of the Jacksons Gap Group quartzite (PCPZjgq), the 

erosion-resistant bedrock that forms the Cherokee 

Ridge along the southeastern border of the park. 

Before the Tallapoosa River enters the park on the 

eastern boundary, it clearly flows around the extent 

of an outcrop of Jackson Gap Group (PCPZjgq). This 

phenomenon is also observed shortly after the river 

leaves the park boundary on the western side: the river 

flows around a mapped outcrop of the Jacksons Gap 

Group quartzite (see poster, in pocket).

Also of note is the course that the river takes when 

it does flow over the different bedrock units. As the 

Tallapoosa River approaches the park from the south, it 

takes a direct path across the hard rocks of the Jacksons 

Gap Group (PCPZjg). Once the river enters the park, it 

flows over the softer Kowaliga Gneiss (PCPZkg), and it is 

into this erodible rock that the characteristic horseshoe 

bend meander was carved.

Erosion and Mass Wasting

During the 2018 conference call, participants identified 

erosion as the primary resource management concern 

of the park. The erosion in the park is primarily caused 

by fluvial processes associated with the Tallapoosa 

River. As discussed elsewhere in this report, the flow 

regime of the Tallapoosa River is controlled by the 

Martin Dam upstream (Figure 11). Other drivers of flow 

include storms and seasonal variation, with higher flow 

rates occurring during spring and peaking in March. 

If park staff members desire quantitative information 

regarding rates of change and channel morphology, 

repeat photography could potentially be used, although 

vegetation cover has prevented high-resolution studies 

from being carried out. Refer to http://go.nps.gov/

grd_photogrammetry for information about using 

photogrammetry for resource management. Also see the 

chapter about fluvial geomorphology (Lord et al. 2009) 

in Geological Monitoring (Young and Norby 2009).

As a result of flooding, the bank on the inside curve of 

the namesake bend collapsed (National Park Service 

2014). This may have been caused by clearing of 

vegetation in the area, because established vegetation 

stabilizes sediment whereas the loss of vegetation 

can destabilize slopes. Vegetation removal occurs in 
14

Horseshoe Bend for three reasons: (1) to clear space for 

visitor use/access, (2) to control invasive plant species, 

and to a lesser extent, (3) as part of an active fire 

management program.

Perennial Streams

One small, unnamed perennial stream flows along the 

south side of the Tallapoosa River (McDonald et al. 

2018). The Southeastern Coastal Network is monitoring 

this stream for traits including bank height and channel 

width. The baseline report for this stream describes 

these traits in detail (McDonald 2020). Investigation 

(McDonald 2019) has also identified the potential for 

at least two more perennial streams in the park. This 

is part of a larger effort of the Southeastern Coastal 

Network to monitor wadeable streams in all network 

parks (https://www.nps.gov/im/secn/index.htm).

Flooding

Since construction of the Martin Dam in 1980, the flow 

regime of the Tallapoosa River within the park has been 

highly regulated. While this means that unpredictable 

storm-induced flooding is almost nonexistent, the river 

is still subject to a sometimes-extreme artificial flow 

regime (Burkholder and Rothenberger 2010). Power 

generation at the dam results in two high-water events 

per day, which causes the river levels to fluctuate as 

much as 1.5 m (5-6 ft). The dam also affects in stream 

flow and water temperature patterns (Burkholder and 

Rothenberger 2010).

Stream Terraces

Participants at the 2012 GRI scoping meeting identified 

a stream terrace (see GRI scoping summary by 

KellerLynn 2013) (Figure 12). Stream terraces are flat 

surfaces that flank an active floodplain, and represent 

a former (now inactive) floodplain from a time when 

the river was at a higher level. Conversation with Jake 

McDonald of the Southeastern Coastal Network during 

the 2018 conference call revealed that many streams in 

the southeastern United States have a historical stream 

terrace bounding any floodplains that may be present. 

These historical stream terraces were formed when an 

increased understanding and implementation of soil 

conservation practices in the early 20th century caused 

streams to incise into historic alluvium as the streams 

tried to re-equilibrate to a system with much less free 

sediment (Trimble 1969).

Climate Change

Because of the potential impacts that climate change 

may have to park resources, including geologic 

resources, a brief discussion of climate change is 

merited in this report. However, climate change 

planning is beyond the scope of the GRI program, and 

park managers are directed to the NPS Climate Change 

Response Program (CCRP) to address issues related to 

climate change (https://www.nps.gov/orgs/ccrp/index.

htm).

Primary effects that climate change may have on natural 

resources in the park are, perhaps unsurprisingly, 

related to fluvial erosion. Directly, any change in storm 

frequency and intensity has the potential to impact the 

occurrence and intensity of flooding. More intense 

floods are more likely to cause significant undercutting 

of banks, which can lead to large-scale mass wasting 

events, such as bank collapse at the inside of the bend.

Many climate models suggest that in addition to 

increasing storm intensity, the intervals between 

storms may also increase as a result of changing climate 

(Kunkel et al. 2013). This could change the type and 

amount of vegetation in riparian areas, making river 

banks more susceptible to erosion.

Climate change may also impact the park’s ephemeral 

streams. Dry periods in the past have led to the 

disappearance of ephemeral streams throughout the 

park, by definition. Ephemeral streams are important 

habitat. “Salamander Creek,” for example, is an 

unnamed, unmonitored ephemeral stream that is home 

to crayfish and at least one salamander (McDonald 

2019). The stream was dry during a 2008 drought, and 

climate change could exacerbate drought and further 

threaten biologically important habitat.

Figure 12. Photograph of stream terrace.

The terrace represents an abandoned floodplain of 

the Tallapoosa River and the lower surface is the 

modern floodplain. As the river cuts deeper into 

the floodplain (or the bedrock), the old floodplain is 

abandoned and becomes a terrace. NPS photograph 

by Rebecca Port, annotations by the author.
15

Brevard Zone

The Brevard zone in Alabama is a 2–3-km- (1–2-mi-) 

wide zone of metamorphosed and deformed rocks 

that separates the Northern and the Inner Piedmont 

sections of the Piedmont physiographic province 

(Guthrie 2009). The Brevard fault zone is a massive 

structural feature that runs 600 km (370 mi) along 

the southern Appalachian Mountains and, along with 

the Emuckfaw Group, forms the western limb of the 

Tallassee Synform (see “Geologic History”).

The Brevard fault zone is defined by the metamorphic 

rocks of the Jacksons Gap Group (PCPZjg) including 

micaceous quartzites (PCPZjgq) (Figure 5h). For a 

thorough discussion of the lithology and geologic 

evolution of the Brevard fault zone as relevant to 

Horseshoe Bend National Military Park, see the 

“Geologic History” section of this report.

Cave Features and Processes

The National Park Service defines a cave as any opening 

in the ground that a human can fit in. Commonly, caves 

exist as part of a karst landscape (a landscape where 

dissolution of the bedrock by flowing water has created 

features such as sinkholes, springs, and caves). These 

landscapes require a soluble bedrock, such as limestone 

or gypsum, which is not present in the park. Marble, 

which is metamorphosed limestone and is soluble, 

exists within the Brevard fault zone but not within the 

park. Therefore, there are no karst features associated 

with the park. See Weary and Doctor (2014) for more 

information about cave and karst features in the United 

States.

There is an erosional feature within the park that 

fits under the broader heading of cave features and 

processes: Wilson’s Rock (Figure 13). A rock overhang 

of unknown cultural significance (KellerLynn 2013, 

2018 GRI conference call), Wilson’s Rock is known to 

park staff and is featured in walking tours of the park. 

The location of Wilson’s Rock is marked on figure 1.

Seismic Activity

Strong seismic activity in the park is mostly historic, 

although earthquakes are occasionally felt within 

the park (KellerLynn 2013). The greatest risk from 

seismic activity to the park (Figure 14) is any impact to 

groundwater flow, which can lead to the loss of water 

in wells. Scoping and conference call participants, 

2012 and 2018, respectively, both mentioned Sandy 

Ebersole (Geological Survey of Alabama) as a source of 

earthquake information for park managers. See Braile 

(2009) for more information about seismic activity in 

parks.

Scoping participants mentioned the Fort Payne (210 km 

[130 mi] north of Horseshoe Bend) earthquake of 29 

April 2003 as significant to the park. The magnitude 4.9 

quake was felt in 13 states but did not cause significant 

damage.

The largest historic earthquake in Alabama occurred 

more than a century ago. The magnitude 5.9 Irondale 

quake damaged more than 20 chimneys in the town of 

Irondale, 145 km (90 mi) northwest of the park (Stover 

and Coffman 1993; KellerLynn 2013).

The New Madrid earthquake of 1811–1812 has cultural 

connections to the park’s history and was likely felt in 

the Horseshoe Bend area (KellerLynn 2013). The New 

Madrid seismic zone (Figure 14) lies within the central 

Mississippi Valley and has historically been the site 

of some of the largest earthquakes in North America. 

Three main shocks occurred between December 1811 

and February 1812; shaking from the last shock was 

felt across 5 million km2

 (2 million mi2) and caused the 

Mississippi River to run backwards. Cultural legend 

holds that the American Indian leader Tecumseh 

predicted the New Madrid earthquake and said it would 

occur when he stomped his foot.

The following are useful resources for park awareness 

of earthquake hazards:

● GRD Seismic Monitoring website: http://go.nps.gov/

geomonitoring.

● US Geological Survey Earthquakes Hazards website: 

https://earthquake.usgs.gov/.

● US Geological Survey New Madrid Seismic Zone 

webpage: https://earthquake.usgs.gov/learn/topics/

nmsz/.

Figure 13. Wilson’s Rock.

Wilson’s Rock is an erosional feature large enough 

for a human to enter. NPS photograph by Brian 

Robinson.
16

● Geological Survey of Alabama Geologic Hazards 

website: https://www.gsa.al.us/gsa/geologic/hazards/

earthquakes/alquakes.

Mining and Minerals

The Brevard fault zone has historically been the site 

of minor gold production, and Tallapoosa County 

was home to gold mining operations from 1842 to 

1936 (Guthrie 2009). There are no current plans for 

commercial mining, and minimal recreational interest 

(KellerLynn 2013). Dane VanDervoort is the current 

economic geologist at the Geological Survey of Alabama 

and oversees tracking the occurrence of mineral 

operations and interest throughout the state; he is a 

contact for information about potential activity near the 

park.

Abandoned Mineral Lands

Abandoned Mineral Lands (AML) are lands, waters, 

and surrounding watersheds that contain facilities, 

structures, improvements, and disturbances associated 

with past mineral exploration, extraction, processing, 

and transportation, including oil and gas features and 

operation, for which the National Park Service takes 

action under various authorities to mitigate, reclaim, 

or restore in order to reduce hazards and impacts to 

resources. Abandoned Mineral Lands in the National 

Park System: Comprehensive Inventory and Assessment

(Burghardt et al. 2014) identified two AML features in 

the park; neither requires mitigation.

The 2013 GRI scoping summary identified one of these 

sites: a pit that was mined for gravel to supply road 

materials within the boundaries of park. The pit is long 

abandoned and mature trees now grow upon it. 

Figure 14. Map of seismic hazard potential around Horseshoe Bend National Military Park. 

Location of park marked with green star. Graphic adapted from the US Geological Survey Earthquakes 

Hazard Program (https://earthquake.usgs.gov/earthquakes/). 
17

Refer to Burghardt et al. (2014) and https://go.nps.gov/

grd_aml for information about AML in the National 

Park System. These resources provide a comprehensive 

inventory of sites, features, and remediation needs.

Paleontological Resources

Paleontological resources, or fossils, are any remains 

of past life preserved in a geologic context. All fossils 

are nonrenewable. Body fossils are any remains of 

the actual organism such as bones, teeth, shells, or 

leaves. Trace fossils are evidence of biological activity; 

examples include burrows, tracks, or coprolites 

(fossil dung). Fossils in NPS areas occur in rocks 

or unconsolidated deposits, museum collections, 

and cultural contexts such as building stones or 

archeological resources. With a few rare exceptions, 

fossils occur exclusively in sedimentary rocks, as 

organisms (or their traces) are buried by sediment and 

preserved in lithified layers. A paleontological resource 

summary of the Southeastern Coast Network including 

Horseshoe Bend National Military Park reported no 

known fossils associated with the park (Tweet et al. 

2009). The 2018 conference call confirmed this status.

As the bedrock of Horseshoe Bend is metamorphic 

and unlikely to yield any fossils, the most likely chance 

of paleontological resources occurring in the park is 

in an archeological context. Paleontological resources 

have been used in tools and jewelry by American Indian 

tribes who may have traded them into possession by the 

Creek peoples who lived in the villages at Horseshoe 

Bend. Therefore, any cultural artifacts discovered in an 

archeological context in the park has the potential to 

contain fossils. Tweet et al. (2009) made the following 

resource-management recommendations for the park:

● Park staff should be encouraged to observe the 

surface deposits for fossil material while conducting 

their usual duties. Staff should document any 

observations with photographs using a common 

item (e.g., pocketknife) for scale. Fossils and their 

associated geologic context (rock matrix) should be 

documented but left in place unless they are subject 

to imminent degradation by artificially accelerated 

natural processes or direct human impacts.

● Fossils found in a cultural context should be 

documented as other fossils but will also require the 

input of an archeologist. Any fossil within a cultural 

context may be culturally sensitive as well (e.g., 

subject to the Native American Graves Protection 

and Repatriation Act [NAGPRA]) and should be 

regarded as such until otherwise established. The 

Southeast Archeology Center (https://www.nps.gov/

seac/index.htm) and the NPS Geologic Resources 

Division can coordinate additional documentation/

research of such material.

● Contact the NPS Geologic Resources Division for 

any additional assistance regarding paleontological 

resource management or interpretation at the park.

Other resources for guidance on paleontological issues 

include:

● The NPS Fossils and Paleontology website: https://

go.nps.gov/paleo.

● Kenworthy and Santucci (2006) presented a 

summary of National Park Service fossil in a cultural 

resource context.

● Santucci et al. (2009) details paleontological resource 

monitoring strategies.

19

Future Geologic Investigations

This section provides some suggestions for future geologic studies. This list is primarily derived 

from various needs identified in the park foundation document; these needs are interpreted as 

having a geologic component. It is not an exhaustive list of research, nor is it a list of the highest 

priority research to support park management. Some of the suggested studies have clear ties to park 

management issues; other studies have broader interests and applications.

The park’s 2014 foundation document (National Park 

Service 2014) identified several fundamental resources 

and values (FRVs), as well as other important resources 

and values (OIRVs), that have data and/or GIS needs 

with geologic components. Fundamental resources 

and values are those features, processes, experiences, 

stories, scenes, sounds, smells, or other attributes 

determined to warrant primary consideration during 

planning and management processes because they 

are essential to achieving the purpose of the park and 

maintaining its significance. Other important resources 

and values are not fundamental to the purpose of the 

park and may be unrelated to its significance but are 

important to consider in planning processes. 

Fundamental resources and values identified at the park 

include the following:

● The battlefield (encompassing the barricade site, 

Tohopeka village site, Lemuel Montgomery gravesite, 

Bean’s Island, the Tallapoosa River, and areas on the 

other side of the river)

● Battle-related artifacts in the museum collection

● Battle-related archeological resources

● Nonbattle-related archeological resources associated 

with the Creek culture

● Tohopeka Village site

● Nuyaka Village site

● Congressional Monument and Jackson Trace marker

Other important resources and values identified at the 

park include the following:

● Miller’s Bridge Piers

● Archeological resources unrelated to the battle or to 

Creek culture

● Artifacts in the collection unrelated to the battle or to 

Creek culture

● Archival materials

● Mission 66 Visitor Center

● The historically prevalent natural and cultural 

landscape (during the period of the significance/

period of the battle)

● Opportunities for recreation, wildlife viewing, and 

water-based recreation

Investigation of erosional change to archeological 

resources is a need for both battle- and non-battlerelated archeological resources associated with Creek 

culture. These resources include known and yet-tobe-discovered artifacts in the battlefield as well as the 

village sites of Tohopeka and Nuyaka, all of which 

could be threatened by increased erosion related to 

climate change. Photogrammetry is an effective method 

of monitoring active processes, including erosional 

change. GRD has acquired equipment and software to 

develop a photogrammetric data program to support 

parks and regions. For more information, contact GRD 

or visit https://www.nps.gov/subjects/geohazards/

photogrammetry.htm.

The GRI GIS data for the park does not include surficial 

deposits. If monument managers are interested in 

acquiring this updated information as part of their GRI 

GIS data, they can contact the NPS Geologic Resources 

Division and/or Inventory and Monitoring Division. 

The next generation of NPS inventories, termed 

“inventories 2.0,” may support such expanded map 

coverages. The estimated starting date for inventories 

2.0 is 2020. Notably, culturally sensitive information 

would not be included in the publicly available GRI GIS 

data.

The foundation document also cites a need for remote 

sensing of archeological resources (opposed to invasive 

archeology). This may be a project that could be 

completed by a Geoscientist-in-the-Parks (GIP; https://

go.nps.gov/gip) or Mosaics in Science (MIS; https://

go.nps.gov/mosaics) intern under the supervision 

of a NPS or state archeologist. This could also be an 

opportunity to investigate archeological resources for 

any paleontological components.

21

Geologic Map Data

A geologic map in GIS format is the principal deliverable of the GRI program. GRI GIS data 

produced for the park follows the source maps listed here and includes components described in this 

chapter. A poster (in pocket) displays the data draped over imagery of the park and surrounding 

area. Complete GIS data are available at the GRI publications website: https://go.nps.gov/gripubs.

Geologic Maps

A geologic map is the fundamental tool for depicting the 

geology of an area. Geologic maps are two-dimensional 

representations of the three-dimensional geometry 

of rock and sediment at or beneath the land surface 

(Evans 2016). The colors on a geologic map indicate 

the rock types or deposits and ages present in an area. 

In addition to color, rocks and deposits are delineated 

as map units, and each map unit is labeled by a symbol. 

Usually, the map unit symbol consists of uppercase 

letters indicating the age (e.g., PC for Precambrian or 

PZ for Paleozoic) and lowercase letters indicating the 

rock formation’s name or the type of deposit (see table 

1). Other symbols on geologic maps depict the contacts 

between map units, and structures such as faults or 

folds, The American Geosciences Institute website, 

https://www.americangeosciences.org/environment/

publications/mapping, provides more information 

about geologic maps and their uses.

Geologic maps are generally one of two types: surficial 

or bedrock. Surficial geologic maps typically encompass 

deposits that are unconsolidated and formed during 

the past 2.6 million years (Quaternary Period). Surficial 

map units are differentiated by geologic process or 

depositional environment. The GRI GIS data for 

Horseshoe Bend National Military Park does not 

include surficial mapping.

Bedrock geologic maps encompass older, typically 

more consolidated sedimentary, metamorphic, and/

or igneous rocks. Bedrock map units are differentiated 

based on age and/or rock type. The 5 bedrock map 

units in the GRI GIS data for the park consist of 

Precambrian to Paleozoic (“PCPZ” units). These map 

unit descriptions are from Jones (2012).

Source Maps

The GRI team does not conduct original geologic 

mapping. Scoping participants (see Appendix A) and 

the GRI team identify the best available geologic maps 

for a park unit. Determinations are made based on 

coverage (extent or area mapped), map scale, date 

of mapping, and compatibility of the mapping to the 

current geologic interpretation of an area. The GRI 

team then digitizes paper maps and/or converts existing 

digital data to the GRI GIS data model. The GRI team 

may compile multiple source maps to cover a park 

boundary or provide a greater extent as needed for 

resource management.

The GRI team used the following source map to 

produce the GRI GIS data for the park and surrounding 

area. The data cover the Jacksons Gap and Buttston 

quadrangles (Figure 15). Information provided in this 

report is based on the following source map:

● Preliminary Geologic Map of the Horseshoe Bend 

National Military Park, Alabama (scale 1:24,000) 

(Jones 2012).

GRI GIS data include essential elements of source maps 

such as map unit descriptions, a correlation chart of 

units, a map legend, map notes, cross sections, figures, 

and references. These items are included in a GRI 

ancillary map information document, which for the 

park is hobe_geology.pdf.

GRI GIS Data

The GRI team standardizes map deliverables by 

implementing a data model that is based on an 

ESRI geodatabase to ensure data quality, product 

consistency, and that a digital map is user friendly 

and well communicated. The GRI GIS data model 

is the architectural blueprint or schema for the GIS 

data; it includes defining data layers based on spatial 

representation (i.e., polygon, line, or point) and 

geologic theme (e.g., faults, folds, and contacts). Feature 

attribution (how feature information is stored) and 

geodatabase topology (spatial relationship rules that 

ensure spatial integrity) are also components of the data 

model. The GRI GIS data for the park was compiled 

using data model version 2.0, which is available at 

https://go.nps.gov/gridatamodel.

GRI GIS data are available on the GRI publications 

website https://go.nps.gov/gripubs and through the NPS 

Integrated Resource Management Applications (IRMA) 

portal https://irma.nps.gov/App/Portal/Home; enter 

“GRI” as the search text and select a park from the unit 

list. The GRI Geologic Maps website, https://go.nps.

gov/geomaps, provides more information about the 

program’s map products.

The following components are part of the data for the 

park:
22

Figure 15. Index map for the GRI GIS data of the park.

Graphic shows the GRI GIS data and the two 7.5 minute quadrangles (Jacksons Gap and Buttston) 

surrounding the park. The NPS boundary of Horseshoe Bend National Military Park (green outline) ends 

at the border of the Buttston quadrangle, but the GRI GIS data continue west into the Jacksons Gap 

quadrangle. Graphic compiled by the author.

Table 2. GRI GIS data layers for Horseshoe Bend National Military Park.

Data Layer On Poster? On Google Earth Layer?

Geologic Attitude and Observation Localities No Yes

Faults Yes Yes

Geologic Contacts Yes Yes

Geologic Units Yes Yes

● A GIS readme file (readme.txt) that describes 

the GRI data formats, naming conventions, 

extraction instructions, use constraints, and contact 

information;

● Data in ESRI geodatabase GIS format;

● An ESRI map document (hobe_geology.mxd) 

that displays the GRI GIS data and allows for user 

interaction and analysis;

● Layer files that contain symbology for each data layer 

(see table 2);

● Federal Geographic Data Committee (FGDC)–

compliant metadata, which are organized in a userfriendly, frequently asked questions (FAQ) format; 

and

● An ancillary map information document (hobe_

geology.pdf) that contains information captured from 

source maps such as map unit descriptions, geologic 
23

unit correlation tables, legends, cross sections, and 

figures.

GRI Map Poster

A poster of the GRI GIS data draped over a shaded 

relief image of the park and surrounding area is 

included with this report. Not all GIS feature classes 

are included on the poster (see table 2). Geographic 

information and selected park features have been 

added to the poster. Digital elevation data and added 

geographic information are not included in the GRI GIS 

data but are available online from a variety of sources. 

Park managers may contact the GRI team for assistance 

locating these data.

Use Constraints

Graphic and written information provided in this 

report and in the accompanying GRI GIS data is not 

a substitute for site-specific investigations. Grounddisturbing activities should neither be permitted nor 

denied based upon the information provided here. Park 

managers may contact the GRI team with any questions.

Minor inaccuracies may exist regarding the locations 

of geologic features relative to other geologic or 

geographic features in the GRI GIS data and on the 

poster. Based on the source map scale (1:24,000) and 

US National Map Accuracy Standards, geologic features 

represented are expected to be horizontally within 12 m 

(40 ft) of their true locations.

25

Literature Cited

These references are cited in this report. Contact the Geologic Resources Division for assistance in 

obtaining them.

Barineau, C.I., Tull, J.F., and Holm-Denoma, C.S., 2015, 

A Laurentian margin back-arc: The Ordovician 

Wedowee-Emuckfaw-Dahlonega basin. Pages 21–78 

in A.E. Holmes, editor. Diverse Excursions in the 

Southeast: Paleozoic to Present: Geological Society 

of America Field Guide 39.

Bobyarchick, A. R., S. H. Edelman, and J. W. Horton, 

Jr. 1988. The role of dextral strike-slip in the 

displacement history of the Brevard zone. Pages 

53–104 in Southeastern geological excursions. 

South Carolina Geological Survey, Columbia, South 

Carolina.

Braile, L. W. 2009. Seismic monitoring. Pages 229–244 

in R. Young, R. and L. Norby, editors. Geological 

monitoring. Geological Society of America, Boulder, 

Colorado. http://go.nps.gov/seismic_monitoring.

Burghardt, J. E., E. S. Norby, and H. S. Pranger II. 2014. 

Abandoned mineral lands in the National park 

System: comprehensive inventory and assessment. 

Natural Resource Technical Report NPS/NRSS/

GRD/NRTR—2014/906. National Park Service, 

Fort Collins, Colorado. http://go.nps.gov/aml_

publications. 

Burkholder, J. M. and M. B. Rothenberger. 2010. 

Assessment of water resources and watershed 

conditions in Horseshoe Bend National Military 

Park, Alabama. Natural Resource Report NPS/

SECN/NRR—2010/268. National Park Service, Fort 

Collins, Colorado.

Evans, T. J. 2016. General standards for geologic maps. 

Section 3.1 in M. B. Carpenter and Keane C. M., 

compilers. The geoscience handbook 2016. AGI Data 

Sheets, 5th Edition. American Geosciences Institute, 

Alexandria, Virginia.

Guthrie, G. M. 2009. Emplacement of gold deposits in 

the eastern Blue Ridge and Brevard zone, Alabama 

Piedmont. Guidebook. Alabama Geological Society, 

46th Annual Field Trip, 4–5 December, 2009, 

Sylacauga, Alabama. The Alabama Geological Society, 

Tuscaloosa, Alabama.

Hawkins, J. F. 2013. Geology, petrology, and 

geochronology of rocks in the Our Town, Alabama 

quadrangle. Thesis. Auburn University, Auburn, 

Alabama.

Henderson, S. W. 2000. The significance of meander 

bends in military history; three examples from 

the Southern United States. Geological Society 

of America, Southeastern Section Abstracts with 

programs 41(7):193

International Commission on Stratigraphy. 2018. 

International chronostratigraphic chart (v2018/08). 

Drafted by K. M. Cohen, D. A. T. Harper, P. L. 

Gibbard, and J.-X. Fan (August 2018). International 

Union of Geological Sciences, International 

Commission on Stratigraphy (ICS), Durham, 

England. http://www.stratigraphy.org/index.php/icschart-timescale.

Jones, K. 2012. Preliminary geologic map of the 

Horseshoe Bend National Military Park, Alabama 

(scale 1:24,000). Thesis. Auburn University, Auburn, 

Alabama.

KellerLynn, K. 2013. Geologic Resources Inventory 

scoping summary Horseshoe Bend National Military 

Park, Alabama. National Park Service, Geologic 

Resources Division, Lakewood, Colorado. https://

go.nps.gov/gripubs.

Kenworthy, J. P. and V. L. Santucci. 2006. A preliminary 

inventory of NPS paleontological resources found in 

cultural resource contexts, Part 1: General Overview. 

Pages 70–76 in S. G. Lucas, J. A. Spielmann, P. M. 

Hester, J. P. Kenworthy, and V. L. Santucci, editors. 

America’s Antiquities (Proceedings of the 7th 

Federal Fossil Conference). Bulletin 34. New Mexico 

Museum of Natural History & Science, Albuquerque, 

New Mexico. Bulletin 34. https://www.nps.gov/

subjects/fossils/research-volumes.htm. 

Kunkel, K. E., L. E. Stevens, S. E. Stevens, L. Sun, 

E. Janssen, D. Wuebbles, M. C. Konrad II, C. E., 

Fuhrman, B. D. Keim, M. C. Kruk, A. Billet, H. 

Needham, M. Schafer, and J. G. Dobson. 2013. 

Regional climate trends and scenarios for the US 

national climate assessment, part 2: climate of the 

southeast US Technical Report NESDIS 142-2, 

National Oceanic and Atmospheric Administration, 

Washington, DC.

Lord, M. L., D. Germanoski, and N. E. Allmendinger. 

2009. Fluvial geomorphology: monitoring stream 

systems in response to a changing environment. 

Pages 69–103 in R. Young and L. Norby, editors. 

Geological monitoring. Geological Society of 

America, Boulder, Colorado. https://go.nps.gov/

geomonitoring. 
26

McClellan, E. A., M. G. Steltenpohl, C. Thomas, and 

C. F. Miller. 2007. Isotopic age constraints and 

metamorphic history of the Talladega belt: new 

evidence for timing of arc magmatism and terrane 

emplacement along the southern Laurentian margin. 

Journal of Geology 115(9):541–561.

McDonald, J. M., M. B. Gregory, J. W. Riley, and E. N. 

Starkey. 2018. Monitoring wadeable stream habitat 

conditions in Southeast Coast Network parks: 

Protocol narrative. Natural Resource Report NPS/

SECN/NRR—2018/1715. National Park Service, Fort 

Collins, Colorado

McDonald, J. M. 2019. Wadeable stream suitability 

assessment for long-term monitoring: Horseshoe 

Bend National Military Park. Natural Resource Data 

Series NPS/SECN/NRDS—2019/1234. National 

Park Service, Fort Collins, Colorado.

McDonald, J. M. 2020. Wadeable stream habitat 

monitoring at Horseshoe Bend National Military 

Park: 2019 baseline report. Natural Resource Report 

NPS/SECN/NRR—2020/2067. National Park 

Service, Fort Collins, Colorado.

McDonald, J. M., M. B. Gregory, J. W. Riley, and E. N. 

Starkey. 2018. Monitoring wadeable stream habitat 

conditions in Southeast Coast Network parks: 

Protocol narrative. Natural Resource Report NPS/

SECN/NRR—2018/1715. National Park Service, Fort 

Collins, Colorado.

National Park Service. 2014. Foundation document, 

Horseshoe Bend National Military Park, Alabama 

(September 2014). HOBE 407/124635. Denver 

Service Center, Denver, Colorado.

National Park Service. 2017. Resource stewardship 

strategy summary, Horseshoe Bend National Military 

Park, Alabama (February 2017). HOBE 407/136532. 

Denver Service Center, Denver, Colorado.

Santucci, V. L., J. P. Kenworthy, and A. L. Mims. 2009. 

Monitoring in situ paleontological resources. 

Pages 189–204 in R. Young and L. Norby, editors. 

Geological monitoring. Geological Society of 

America, Boulder, Colorado. http://go.nps.gov/

paleo_monitoring. 

Steltenpohl, M., and R. Singleton. 2014. Geology of the 

Buttston 7.5-minute quadrangle, Tallapoosa County, 

Alabama (scale 1:24,000). Geological Survey of 

Alabama, Tuscaloosa, Alabama.

Stover, C. W., and J. L. Coffman. 1993. Seismicity of 

the United States, 1568-1989 (revised). Professional 

Paper 1527. US Geological Survey, Washington, DC.

Thomas, W.A., 2006, Tectonic inheritance at a 

continental margin: GSA Today 16(2):4–11. https://

www.geosociety.org/gsatoday/archive/16/2/pdf/

gt0602.pdf.

Trimble, S. W. 1969. Culturally accelerated 

sedimentation on the middle Georgia Piedmont, US 

Soil Conservation Service, Fort Worth, Texas.

Tull, J. F., C. I. Barineau, P. A. Mueller, and J. L. 

Wooden, 2007. Volcanic arc emplacement onto 

the southernmost Appalachian Laurentian shelf: 

characteristics and constraints: Geological Society of 

America Bulletin 119(3/4):261–274.

Tull, J. F., C. I. Barineau, and C. S. Holm-Denoma, 2012. 

Characteristics, extent, and tectonic significance 

of a Middle Ordovician back-arc basin in the 

southern Appalachian Blue Ridge. Pages 12–26 in 

C. I. Barineau and J. F. Tull, editors. The Talladega 

slate belt and eastern Blue Ridge: Laurentian plate 

passive margin to back-arc basin tectonics in the 

southern Appalachian orogen, 49th Annual Fieldtrip 

Guidebook. Alabama Geological Society, Tuscaloosa, 

Alabama.

Tweet, J. S., V. L. Santucci, and J. P. Kenworthy. 2009. 

Paleontological resource inventory and monitoring 

Southeast Coast Network. Natural Resource 

Technical Report NPS/NRPC/NRTR—2009/197. 

National Park Service, Fort Collins, Colorado.

Weary, D.J., and D. H. Doctor. 2014, Karst in the United 

States: A digital map compilation and database. 

Open-File Report 2014–1156. US Geological 

Survey, Reston, Virginia. https://pubs.usgs.gov/

of/2014/1156/.

Winter, J. 2001. An introduction to igneous and 

metamorphic petrology. Prentice Hall, New Jersey.

Young, R. and L. Norby, editors. 2009. Geological 

monitoring. Geological Society of America, Boulder, 

Colorado. http://go.nps.gov/geomonitoring.
27

Additional Resources

These websites, online information, and books may be of use for geologic resources management 

and interpretation at Horseshoe Bend National Military Park.

Climate Change

● Intergovernmental Panel on Climate Change: https://

www.ipcc.ch/

● NPS Climate Change Response Program Resources: 

https://www.nps.gov/subjects/climatechange/

resources.htm

● The Climate Analyzer (an interactive website that 

allows users to create custom graphs and tables from 

historical and current weather-station data: https://

www.climateanalyzer.org/

● US Global Change Research Program: https://www.

globalchange.gov/home

Geological Surveys and Societies

● Geological Survey of Alabama: https://www.gsa.state.

al.us

● American Geophysical Union: https://sites.agu.org/

● American Geosciences Institute: https://www.

americangeosciences.org/

● Association of American State Geologists: https://

www.stategeologists.org/

● Geological Society of America: https://www.

geosociety.org/

● US Geological Survey (USGS): https://www.usgs.gov/

NPS Geology Interpretation and Education

● America’s Geologic Heritage: An Invitation to 

Leadership by the NPS Geologic Resources 

Division and American Geosciences Institute 

(AGI). Published in 2015 by AGI: https://go.nps.gov/

AmericasGeoheritage

● NPS Geologic Resources Division Education 

website: https://go.nps.gov/geoeducation

● NPS Geoscientist-In-the-Parks (GIP) internship and 

guest scientist program: https://go.nps.gov/gip

● NPS Mosaics-In-Science (MIS) internship program: 

https://go.nps.gov/mis

● Parks and Plates: The Geology of Our National Parks, 

Parks, and Seashores by Robert J. Lillie (Oregon State 

University). Published in 2005 by W. W. Norton and 

Company, New York.

NPS Resource Management Guidance and 

Documents

● 1998 National parks omnibus management act: 

https://www.gpo.gov/fdsys/pkg/PLAW-105publ391/

pdf/PLAW-105publ391.pdf

● Appendix B of the GRI report.

● Geological Monitoring by Rob Young and Lisa 

Norby. Published in 2009 by the Geological Society 

of America. Available online at https://go.nps.gov/

geomonitoring

● Management Policies 2006 (Chapter 4: Natural 

resource management): https://www.nps.gov/policy/

mp/policies.html

● NPS-75: Natural resource inventory and monitoring 

guideline: https://www.nature.nps.gov/nps75/nps75.

pdf

● NPS Natural resource management reference manual 

#77: https://www.nature.nps.gov/Rm77/

● NPS Technical Information Center (TIC) (Denver, 

Colorado; repository for technical documents): 

https://www.nps.gov/dsc/technicalinfocenter.htm

US Geological Survey (USGS) Reference Tools

● National Geologic Map Database (NGMDB): https://

ngmdb.usgs.gov/ngmdb/ngmdb_home.html

● US Geologic Names Lexicon (Geolex; geologic unit 

nomenclature and summary): https://ngmdb.usgs.

gov/Geolex/search

● Geographic Names Information System (GNIS; 

official listing of place names and geographic 

features): https://gnis.usgs.gov/

● GeoPDFs (download PDFs of any topographic map 

in the United States): https://store.usgs.gov (click on 

“Map Locator”)

● Publications warehouse (USGS publications available 

online): https://pubs.er.usgs.gov

● Tapestry of Time and Terrain (descriptions of 

physiographic provinces): https://pubs.usgs.gov/

imap/i2720/

29

Appendix A: Scoping Participants

The following people attended the GRI scoping meeting, held on 8 May 2006, or the follow-up 

report writing conference call, held on 21 February 2018. Discussions during these meetings 

supplied a foundation for this GRI report. The scoping summary document is available on the GRI 

publications website: http://go.nps.gov/gripubs.

2012 Scoping Meeting Participants

Name Affiliation Position

Joel Abrahams Auburn University Graduate Student

Jim Cahill Horseshoe Bend National Military Park Chief Ranger

Kelly Gregg Jacksonville State University Geologist

John Hawkins Auburn University Graduate Student

Bruce Heise NPS Geologic Resources Division Geologist/GRI Program Coordinator

Georgia Hybels NPS Geologic Resources Division Geologist/GIS Specialist

Kevin Jones Auburn University Undergraduate Student

Katie KellerLynn Colorado State University Geologist/Research Associate/Report Writer

Ed Osborne Geological Survey of Alabama Geologist/Program Director

Josh Poole University of West Georgia Undergraduate Student

Rebecca Port Colorado State University Research Associate

Doyle Sapp Horseshoe Bend National Military Park Superintendent

Mark Steltenpohl Auburn University Department of Geography and Geology, 

Professor and Chair

2018 Conference Call Participants

Name Affiliation Position

Michael Barthelmes Colorado State University Geologist/Research Associate/Report Writer

Don Irvin Alabama Geological Survey Geologic Map Coordinator

Jason Kenworthy NPS Geologic Resources Division Geologic Resources Inventory Coordinator

Jake McDonald NPS Southeast Coast Network Geomorphologist

Brian Robinson Horseshoe Bend National Military Park Maintenance Mechanic

Stacy Speas Horseshoe Bend National Military Park Lead Park Ranger

31

Appendix B: Geologic Resource Laws, Regulations, and Policies

The NPS Geologic Resources Division developed this table to summarize laws, regulations, and 

policies that specifically apply to NPS minerals and geologic resources. The table does not include 

laws of general application (e.g., Endangered Species Act, Clean Water Act, Wilderness Act, 

National Environmental Policy Act, or National Historic Preservation Act). The table does include 

the NPS Organic Act when it serves as the main authority for protection of a particular resource 

or when other, more specific laws are not available. Information is current as of December 2017. 

Contact the NPS Geologic Resources Division for detailed guidance.

Resource Resource-specific Laws Resource-specific 

Regulations

2006 Management Policies

Paleontology

National Parks Omnibus 

Management Act of 1998, 54 USC 

§ 100701 protects the confidentiality 

of the nature and specific location 

of paleontological resources and 

objects.

Paleontological Resources 

Preservation Act of 2009, 16 USC 

§ 470aaa et seq. provides for the 

management and protection of 

paleontological resources on federal 

lands.

Archaeological Resources 

Protection Act of 1979, 16 USC 

§§ 470aa – mm Section 3 (1) 

Archaeological Resource—

nonfossilized and fossilized 

paleontological specimens, or 

any portion or piece thereof, shall 

not be considered archaeological 

resources, under the regulations of 

this paragraph, unless found in an 

archaeological context. Therefore, 

fossils in an archaeological context 

are covered under this law. 

Federal Cave Resources 

Protection Act of 1988, 16 USC 

§§ 4301 – 4309 Section 3 (5) Cave 

Resource—the term “cave resource” 

includes any material or substance 

occurring naturally in caves on 

Federal lands, such as animal life, 

plant life, paleontological deposits, 

sediments, minerals, speleogens, 

and speleothems. Therefore, every 

reference to cave resource in the law 

applies to paleontological resources.

36 CFR § 2.1(a)(1)(iii)

prohibits destroying, 

injuring, defacing, removing, 

digging or disturbing 

paleontological specimens 

or parts thereof.

Prohibition in 36 CFR § 

13.35 applies even in Alaska 

parks, where the surface 

collection of other geologic 

resources is permitted.

43 CFR Part 49 (in 

development) will contain 

the DOI regulations 

implementing the 

Paleontological Resources 

Preservation Act.

Section 4.8.2 requires NPS to protect 

geologic features from adverse effects of 

human activity.

Section 4.8.2.1 emphasizes Inventory and 

Monitoring, encourages scientific research, 

directs parks to maintain confidentiality of 

paleontological information, and allows 

parks to buy fossils only in accordance with 

certain criteria.
32

Resource Resource-specific Laws Resource-specific 

Regulations

2006 Management Policies

Recreational Collection of Rocks Minerals

NPS Organic Act, 54 USC. § 

100101 et seq. directs the NPS to 

conserve all resources in parks (which 

includes rock and mineral resources) 

unless otherwise authorized by law.

Exception: 16 USC. § 445c (c) – 

Pipestone National Park enabling 

statute. Authorizes American Indian 

collection of catlinite (red pipestone).

36 C.F.R. § 2.1 prohibits 

possessing, destroying, 

disturbing mineral 

resources...in park units.

Exception: 36 C.F.R. § 7.91

allows limited gold panning 

in Whiskeytown. 

Exception: 36 C.F.R. § 

13.35 allows some surface 

collection of rocks and 

minerals in some Alaska 

parks (not Klondike Gold 

Rush, Sitka, Denali, Glacier 

Bay, and Katmai) by nondisturbing methods (e.g., 

no pickaxes), which can be 

stopped by superintendent 

if collection causes 

significant adverse effects 

on park resources and visitor 

enjoyment.

Section 4.8.2 requires NPS to protect 

geologic features from adverse effects of 

human activity.

Mining Claims (Locatable Minerals)

Mining in the Parks Act of 1976, 

54 USC § 100731 et seq. authorizes 

NPS to regulate all activities resulting 

from exercise of mineral rights, on 

patented and unpatented mining 

claims in all areas of the System, in 

order to preserve and manage those 

areas.

General Mining Law of 1872, 30 

USC § 21 et seq. allows US citizens 

to locate mining claims on Federal 

lands. Imposes administrative and 

economic validity requirements for 

“unpatented” claims (the right to 

extract Federally-owned locatable 

minerals). Imposes additional 

requirements for the processing of 

“patenting” claims (claimant owns 

surface and subsurface). Use of 

patented mining claims may be 

limited in Wild and Scenic Rivers 

and OLYM, GLBA, CORO, ORPI, and 

DEVA. 

Surface Uses Resources Act of 

1955, 30 USC § 612 restricts surface 

use of unpatented mining claims to 

mineral activities.

36 CFR § 5.14 prohibits 

prospecting, mining, and 

the location of mining 

claims under the general 

mining laws in park areas 

except as authorized by law.

36 CFR Part 6 regulates 

solid waste disposal sites in 

park units.

36 CFR Part 9, Subpart 

A requires the owners/

operators of mining claims 

to demonstrate bona fide 

title to mining claim; submit 

a plan of operations to NPS 

describing where, when, 

and how; prepare/submit 

a reclamation plan; and 

submit a bond to cover 

reclamation and potential 

liability.

43 CFR Part 36 governs 

access to mining claims 

located in, or adjacent to, 

National Park System units 

in Alaska.

Section 6.4.9 requires NPS to seek to 

remove or extinguish valid mining claims in 

wilderness through authorized processes, 

including purchasing valid rights. Where 

rights are left outstanding, NPS policy is 

to manage mineral-related activities in 

NPS wilderness in accordance with the 

regulations at 36 CFR Parts 6 and 9A.

Section 8.7.1 prohibits location of new 

mining claims in parks; requires validity 

examination prior to operations on 

unpatented claims; and confines operations 

to claim boundaries.
33

Resource Resource-specific Laws Resource-specific 

Regulations

2006 Management Policies

Climate Change

Secretarial Order 3289 (Addressing 

the Impacts of Climate Change on 

America’s Water, Land, and Other 

Natural and Cultural Resources) 

(2009) requires DOI bureaus and 

offices to incorporate climate 

change impacts into long-range 

planning; and establishes DOI 

regional climate change response 

centers and Landscape Conservation 

Cooperatives to better integrate 

science and management to address 

climate change and other landscape 

scale issues.

Executive Order 13693 (Planning 

for Federal Sustainability in the 

Next Decade) (2015) established 

to maintain Federal leadership in 

sustainability and greenhouse gas 

emission reductions.

None Applicable.

Section 4.1 requires NPS to investigate 

the possibility to restore natural ecosystem 

functioning that has been disrupted by past 

or ongoing human activities. This would 

include climate change, as put forth by 

Beavers et al. (in review).

NPS Climate Change Response Strategy

(2010) describes goals and objectives to 

guide NPS actions under four integrated 

components: science, adaptation, mitigation, 

and communication.

Policy Memo 12-02 (Applying National 

Park Service Management Policies in the 

Context of Climate Change) (2012) applies 

considerations of climate change to the 

impairment prohibition and to maintaining 

“natural conditions”.

Policy Memo 14-02 (Climate Change and 

Stewardship of Cultural Resources) (2014) 

provides guidance and direction regarding 

the stewardship of cultural resources in 

relation to climate change.

Policy Memo 15-01 (Climate Change 

and Natural Hazards for Facilities) (2015) 

provides guidance on the design of facilities 

to incorporate impacts of climate change 

adaptation and natural hazards when 

making decisions in national parks.

DOI Manual Part 523, Chapter 1

establishes policy and provides guidance for 

addressing climate change impacts upon the 

Department’s mission, programs, operations, 

and personnel.

Revisiting Leopold: Resource 

Stewardship in the National Parks (2012) 

will guide US National Park natural and 

cultural resource management into a second 

century of continuous change, including 

climate change.

Climate Change Action Plan (2012) 

articulates a set of high-priority no-regrets 

actions the NPS will undertake over the next 

few years

Green Parks Plan (2013) is a long-term 

strategic plan for sustainable management 

of NPS operations.
34

Resource Resource-specific Laws Resource-specific 

Regulations

2006 Management Policies

Soils

Soil and Water Resources 

Conservation Act, 16 USC §§ 

2011–2009 provides for the 

collection and analysis of soil and 

related resource data and the 

appraisal of the status, condition, 

and trends for these resources.

Farmland Protection Policy Act, 

7 USC § 4201 et. seq. requires NPS 

to identify and take into account the 

adverse effects of Federal programs 

on the preservation of farmland; 

consider alternative actions, and 

assure that such Federal programs 

are compatible with State, unit 

of local government, and private 

programs and policies to protect 

farmland. NPS actions are subject 

to the FPPA if they may irreversibly 

convert farmland (directly or 

indirectly) to nonagricultural use and 

are completed by a Federal agency 

or with assistance from a Federal 

agency. Applicable projects require 

coordination with the Department 

of Agriculture’s Natural Resources 

Conservation Service (NRCS).

7 CFR Parts 610 and 611 

are the US Department 

of Agriculture regulations 

for the Natural Resources 

Conservation Service. 

Part 610 governs the 

NRCS technical assistance 

program, soil erosion 

predictions, and the 

conservation of private 

grazing land. Part 611 

governs soil surveys and 

cartographic operations. 

The NRCS works with the 

NPS through cooperative 

arrangements.

Section 4.8.2.4 requires NPS to

-prevent unnatural erosion, removal, and 

contamination;

-conduct soil surveys;

-minimize unavoidable excavation; and

-develop/follow written prescriptions 

(instructions).
35

The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides 

scientific and other information about those resources; and honors its special responsibilities to American Indians, 

Alaska Natives, and affiliated Island Communities.

NPS 407/171160, July 2020
National Park Service

U.S. Department of the Interior

Natural Resources Stewardship and Science

1201 Oak Ridge Drive, Suite 150

Fort Collins, Colorado 80525

https://www.nps.gov/nature/index.htm

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