Carlsbad Caverns National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/003 

National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 
THIS PAGE: 

The Big Room, Carlsbad Caverns NP. 

ON THE COVER: 

Stalactites and draperies decorate the Dome 

Room, Carlsbad Caverns NP 

Photos by: Ronal Kerbo 
Carlsbad Caverns National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/003 

Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, Colorado 80225 

June 2007 

U.S. Department of the Interior 

Washington, D.C.
The Natural Resource Publication series addresses natural resource topics that are of interest 

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general, diverse audience, and may contain NPS policy considerations or address sensitive 

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series include vital signs monitoring plans; "how to" resource management papers; 

proceedings of resource management workshops or conferences; annual reports of resource 

programs or divisions of the Natural Resource Program Center; resource action plans; fact 

sheets; and regularly- published newsletters. 

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Printed copies of reports in these series may be produced in a limited quantity and they are 

only available as long as the supply lasts. This report is also available from the Geologic 

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gre_publications) on the internet, or by sending a request to the address on the back cover. 

Please cite this publication as: 

Graham, J. 2007. Carlsbad Caverns National Park Geologic Resource Evaluation Report. 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/003. National Park Service, Denver, 

Colorado. 

NPS D- 139, June 2007 
 CAVE Geologic Resource Evaluation Report iii

Table of Contents 

List of Figures .............................................................................................................. iv

List of Tables ................................................................................................................ iv

Executive Summary ...................................................................................................... 1

Introduction ................................................................................................................... 2

Purpose of the Geologic Resources Evaluation Program...........................................................................................2

Regional Description ..................................................................................................................................................2

General Geology ........................................................................................................................................................3

Park History................................................................................................................................................................3

Geologic Issues............................................................................................................. 7

Water Contamination..................................................................................................................................................7

Cave Preservation......................................................................................................................................................7

Water Supply and Rattlesnake Springs ......................................................................................................................8

Mineral Resources......................................................................................................................................................9

Paleontological Resources .......................................................................................................................................11

Bats and Bat Habitat Management...........................................................................................................................11

Microbes and Lechuguilla Cave................................................................................................................................12

Guides and Maps for Interpretation ..........................................................................................................................12

Carlsbad Caverns National Park Planning Documents ............................................................................................12

Geologic Features and Processes............................................................................. 15

Formation of Carlsbad Cavern..................................................................................................................................15

Speleothems.............................................................................................................................................................15

Park Caves...............................................................................................................................................................16

Caves Outside the Park............................................................................................................................................17

Permian Reef Features ............................................................................................................................................17

Fossils ......................................................................................................................................................................18

Structural Features...................................................................................................................................................19

Map Unit Properties .................................................................................................... 25

Map Unit Properties Table........................................................................................................................................26

Geologic History.......................................................................................................... 29

Glossary....................................................................................................................... 35

References................................................................................................................... 36

Appendix A: Geologic Map Graphic .......................................................................... 39

Appendix B: Scoping Summary................................................................................. 41

Attachment 1: Geologic Resource Evaluation Products CD 
 NPS Geologic Resources Division iv 

List of Figures 

Figure 1. Location map of Carlsbad Caverns National Park. .........................................................................................4

Figure 2. Major physiographic features of the Permian Basin........................................................................................5

Figure 3. Schematic cross-section and stratigraphic column for Carlsbad Caverns National Park ................................6

Figure 4. Inferred distribution of depositional facies in the lower and upper Guadalupian strata .................................14

Figure 5. Schematic diagram illustrating the evolution of the cave system at CAVE....................................................20

Figure 6. Speleothems in The Big Room .....................................................................................................................21

Figure 7. More Speleothems in the Big Room .............................................................................................................22

Figure 8. Diorama of the Capitan reef ..........................................................................................................................23

Figure 9 Shelf-to-basin spectrum of depositional environments for the Capitan reef. ..................................................24

Figure 10. Tepee structure in Tansill Formation...........................................................................................................24

Figure 11. Geologic time scale.....................................................................................................................................32

Figure 12. Continental reconstruction during Late Permian (Kazanian) time.. .............................................................33

Figure 13. Hypothetical views of the Delaware Basin during sea-level low- and highstands .......................................34

List of Tables

Table 1: Producing units in the Delaware Basin...........................................................................................................10
 CAVE Geologic Resource Evaluation Report 1

Executive Summary 

This report has been developed to accompany the digital geologic map produced by Geologic 

Resource Evaluation staff for Carlsbad Caverns National Park. It contains information 

relevant to resource management and scientific research. 

Established as a unit of the National Park System in 1923, 

Carlsbad Caverns National Park preserves Carlsbad 

Caverns and numerous other caves within an ancient 

fossil reef while protecting an extraordinary and unique 

ecological association of bats, cave climate, speleothems, 

hydrology, cave fauna, and microbes. In 1995, the United 

Nations recognized the worldwide significance of the 

spectacular natural resources at Carlsbad Caverns 

National Park by designating it as a World Heritage Site. 

Preservation and management of the geologic resources 

are important for enhancement of the visitor’s 

experience and sustenance of the ecosystem. 

Over 300 caves are known in the Guadalupe Mountains, 

and more than 100 caves have been surveyed inside the 

boundary of Carlsbad Caverns National Park. 

Decorations in these caves are arguably unsurpassed in 

the world and include dazzling gypsum chandeliers, 

sheet-like draperies, towering columns and domes, 

delicate soda-straw stalactites and other speleothems of 

great abundance and variation. The Big Room is the 

largest cave chamber in North America. 

Carlsbad Caverns is also an extraordinary example of 

aggressive sulfuric acid dissolution. Most of the world’s 

caves have developed through dissolution of limestone 

by weak carbonic acid, a by-product of meteoric 

groundwater and carbon dioxide. At Carlsbad Caverns, 

hydrogen sulfide migrated upward from deeply buried 

petroleum reservoirs and reacted with groundwater, 

forming sulfuric acid, dissolving the Capitan Limestone. 

The dramatic landscape of the park is part of the 

Guadalupe Mountains, a mountain range recognized as 

the best-preserved Permian fossil reef in the world. Reef 

limestones form the prominent Guadalupe Escarpment 

and back-reef carbonates form the canyons and plateaus 

to the northwest. Geologists from all over the world 

come to the Guadalupe Mountains to study this Permian 

reef complex. 

Carlsbad Caverns National Park lies just 5 miles (8 km) 

north of Guadalupe Mountains National Park along 

Guadalupe ridge. Each year over 500,000 visitors place 

increasing demands on the resources of Carlsbad 

Caverns. 

The following issues, features, and processes were 

identified at scoping sessions as having critical 

management significance to the park: 

• Water contamination: Infiltration of contaminated 

water from parking lots and sewer lines has the 

potential to impact the entire ecosystem, destroying 

cave features and the habitat of the world-famous 

colony of migratory Mexican free-tailed bats. This 

situation has resulted in the re-evaluation of 

infrastructure above the cave and measures to prevent 

contaminated water from entering the cave. 

• Cave preservation: Caves contain delicate nonrenewable resources and are a component of fragile 

karstic eco-systems. The continual use, development, 

and exploration of caves can have an extremely 

detrimental impact on those resources and ecosystems. Food, chewing gum, litter, lint, and urine are 

left behind by visitors to the developed caves as well as 

the undeveloped caves of the park. In the past, as many 

as 2,000 speleothems each year were vandalized or 

stolen from Carlsbad Cavern. Measures are being 

taken to reduce human impacts to park caves. One 

such measure has been the implementation of strict 

rules that cavers must follow to prevent the 

destruction of cave features and native microbes in 

Lechuguilla Cave. 

• Water supply and Rattlesnake Springs: Rattlesnake 

Springs is the sole water supply source for the park 

and provides a vital wetland habitat for several species 

of threatened birds and fish. Contamination of the 

groundwater and groundwater flow paths continue to 

be management concerns. 

• External mineral extraction and associated hazards: 

Carlsbad Caverns is surrounded by active 

hydrocarbon exploration that could have a negative 

impact on cave resources. The extraction of mineral 

commodities such as potash also occurs in the vicinity 

of the park. 

• Paleontological resources: Marine invertebrate fossils 

are critical to the determination of Permian reef 

environments, and the identification of surface 

exposures at Carlsbad Caverns. These fossils provide a 

remarkable outdoor laboratory to study this ancient 

ecosystem. In addition, exemplary Pleistocene fossils 

are found in several of the caves at the park. 

Preservation and protection of paleontological 

resources from theft and destruction is critical to 

maintaining their scientific value and the visitor 

experience. 

• Bat habitat: The survival of the park’s population of 

migratory Mexican free-tailed bats depends upon 

understanding the relationship between geology and 

the environment. 
 NPS Geologic Resources Division 2 

Introduction 

The following section briefly describes the regional geologic setting and the National 

Park Service Geologic Resource Evaluation Program. 

Purpose of the Geologic Resources Evaluation Program 

The Geologic Resource Evaluation (GRE) Program is 

one of 12 inventories funded under the NPS Natural 

Resource Challenge designed to enhance baseline 

information available to park managers. The program 

carries out the geologic component of the inventory 

effort from the development of digital geologic maps to 

providing park staff with a geologic report tailored to a 

park’s specific geologic resource issues. The Geologic 

Resources Division of the Natural Resource Program 

Center administers this program. The GRE team relies 

heavily on partnerships with the U.S. Geological Survey, 

Colorado State University, state surveys, and others in 

developing GRE products. 

The goal of the GRE Program is to increase 

understanding of the geologic processes at work in parks 

and provide sound geologic information for use in park 

decision making. Sound park stewardship relies on 

understanding natural resources and their role in the 

ecosystem. Geology is the foundation of park 

ecosystems. The compilation and use of natural resource 

information by park managers is called for in section 204 

of the National Parks Omnibus Management Act of 1998 

and in NPS-75, Natural Resources Inventory and 

Monitoring Guideline. 

To realize this goal, the GRE team is systematically 

working towards providing each of the identified 270 

natural area parks with a geologic scoping meeting, a 

digital geologic map, and a geologic report. These 

products support the stewardship of park resources and 

are designed for non-geoscientists. During scoping 

meetings the GRE team brings together park staff and 

geologic experts to review available geologic maps and 

discuss specific geologic issues, features, and processes. 

Scoping meetings are usually held for individual parks 

and on occasion for an entire Vital Signs Monitoring 

Network. The GRE mapping team converts the geologic 

maps identified for park use at the scoping meeting into 

digital geologic data in accordance with their innovative 

Geographic Information Systems (GIS) Data Model. 

These digital data sets bring an exciting interactive 

dimension to traditional paper maps by providing 

geologic data for use in park GIS and facilitating the 

incorporation of geologic considerations into a wide 

range of resource management applications. The newest 

maps come complete with interactive help files. As a 

companion to the digital geologic maps, the GRE team 

prepares a park-specific geologic report that aids in use 

of the maps and provides park managers with an 

overview of park geology and geologic resource 

management issues. 

For additional information regarding the content of this 

report and up to date GRE contact information please 

refer to the Geologic Resource Evaluation web site 

(http://www2.nature.nps.gov/geology/inventory/). 

Regional Description 

Carlsbad Caverns National Park, was proclaimed a 

national monument in 1923 and established as a national 

park in 1930. The park preserves over 100 known caves 

formed within a Permian-age fossil reef in southeastern 

New Mexico. One of the major cave systems in the park, 

Lechuguilla Cave, is the nation’s deepest limestone cave 

(1,593 feet [486 m]) and the third longest. Lechuguilla 

contains speleothems and microbes found nowhere else 

in the world. The Big Room in Carlsbad Cavern is the 

largest, most easily accessible chamber in North America. 

The United Nations recognized the worldwide 

significance of the natural resources at Carlsbad Caverns 

National Park by designating the park a World Heritage 

Site in 1995. 

Located less than 5 miles (8 km) north of Guadalupe 

Mountains National Park and about 20 miles (32 km) 

southwest of Carlsbad, New Mexico, Carlsbad Caverns 

National Park incorporates 46,766 acres in two separate 

units (figure 1) (NPS 1996). The main unit extends for 

about 21 miles (34 km) southwestward along the Capitan 

Reef and varies from 3 to 6 miles (5 to 10 km) wide. This 

unit contains the cavern that gives the park its name and 

most of the park development, which was built on top of 

the reef escarpment. The backcountry stretches for miles 

to the west and southand includes the escarpment and 

several deeply cut canyons. 

The separate Rattlesnake Springs unit contains about 80 

acres and lies 7 miles (11 km) southwest of the park 

entrance. Rattlesnake Springs is the source of the park’s 

water supply. 

Elevations in the park range from 3,596 feet (1,096 m) in 

the lowlands to 6,368 feet (1,941 m) on the escarpment. 

About 71 percent of the park (33,125 acres) is designated 

wilderness and is managed according to the provisions of 

the Wilderness Act and NPS wilderness policies. 

Carlsbad Caverns is rich not only in geologic history but 

also with cultural resources reflecting a long and varied 

history of human occupation. This history attests to the 

ability of humans to adapt to the harsh Chihuahuan 

Desert environment. About one million artifacts are 

preserved and protected in the park museum. These 

artifacts represent prehistoric and historic Native 

American occupations, European exploration and 

settlement, industrial exploitation, commercial and 

cavern accessibility development, and tourism, which 

have each left their mark on the area. Two historic 

districts, the Cavern Historic District and the Rattlesnake 
 CAVE Geologic Resource Evaluation Report 3

Springs Historic District, are on the National Register of 

Historic Places. 

General Geology 

Carlsbad Caverns National Park is located within the 

Guadalupe Mountains, a limestone mountain range 

recognized as the best-preserved Permian-aged fossil 

reef in the world. The fossils here reveal a detailed 

picture of life along the coastline of a shallow inland sea 

240 – 280 million years ago. Eventually, the coastline 

became a horseshoe-shaped limestone layer of rock over 

1,800 ft (550 m) thick, 2 – 3 mi (3 – 5 km) wide and over 

400 mi (640 km) long that bordered the Delaware Basin 

(figure 2). The Delaware and Midland basins are part of 

the Permian Basin, one of the most productive petroleum 

provinces in North America. 

By the end of the Permian age sediments thousands of 

feet thick covered the Capitan reef burying it for tens of 

millions of years. Local faulting and stresses, especially 

over the past 20 million years, uplifted these reef 

sediments almost 10,000 feet (3,000 m) and tilted the 

uplifted block to the east. Wind, rain, and snow have 

since eroded away the overlying rock exposing the 

ancient reef to the surface once again. The reef 

limestones now form the prominent Guadalupe 

Escarpment, a physiographic feature oriented northeastsouthwest. The deep canyons and caves of Carlsbad 

Caverns allow visitors to view this Permian reef from the 

inside. 

The Permian stratigraphic section at the park records 

back-reef, reef, and fore-reef environments (figure 3). 

Fine-grained layers of siltstone in the back-reef strata are 

low permeability barriers to groundwater flow and 

provide a cap rock against further erosion (Van der 

Heijde et al. 1997). Along with brecciated fore-reef 

limestones, cavernous, fractured, massive reef limestones 

constitute the Capitan Formation. 

The Guadalupe Mountains contain over 300 known 

caves and more than 100 have been surveyed inside 

Carlsbad Caverns National Park (NPS fact sheet 2005). 

Many of these caves exhibit the characteristically large 

rooms associated with sulfuric acid dissolution. The 370-

ft (113 m)-high, 14-acre Big Room in Carlsbad Caverns, 

for example, is the largest cave chamber in North 

America (Kiver and Harris 1999). 

At present, Carlsbad Cavern is relatively dry due to the 

arid nature of the surface climate. The dripping heard 

today inside the cavern is only an echo of what would 

have been heard during prior, wetter times. If in the 

future, the climate becomes wetter the growth of 

speleothems will accelerate, conversely a more arid 

environment will slow speleothem growth. 

Park History 

Stories have it that in the late 1800s James Larkin White, 

a local cowboy in southeastern New Mexico, 

investigated a column of “smoke” and found millions of 

bats emerging from a huge hole in the ground. This 

became known as “Bat Cave.” Bat Cave was later named 

Carlsbad Cave before becoming Carlsbad Cavern. 

Seeking a profit, miners staked claims and removed over 

100,000 tons of bat guano, an extremely rich fertilizer, 

from Carlsbad and other Guadalupe Mountains caves 

from 1901 – 1921. The guano was shipped to the citrus 

groves in California. The floor of Bat Cave was lowered 

by as much as 50 feet (15 m), but none of the companies 

selling bat guano were profitable (Kiver and Harris 

1999). 

During the early 1900s, Jim White was working as a 

guano miner and began to explore the cave and guide 

interested people into the lower chambers. On one of 

these tours, Robert Halley of the General Land Office, 

Department of the Interior, was so impressed with the 

beauty of the caverns that his report led President 

Coolidge to establish Carlsbad Caverns as a national 

monument in 1923. In 1924, an article written by Willis 

T. Lee, a noted U.S. Geological Survey geologist who had 

led a 6-month National Geographic expedition to the 

cave, appeared in National Geographic magazine. Lee’s 

article led to increased public interest and the 

subsequent elevation to national park status in 1930. 

Exploration of the caves at Carlsbad Caverns National 

Park continues to enrich the park’s history. Over a 

period of 2 years, a group of cave explorers slowly 

removed rubble from a blocked passage in a cave about 3 

miles (4.8 km) from the entrance to Carlsbad Cavern. A 

strong flow of air indicated that more passages probably 

existed beyond the blocked passage. In 1986, explorers 

finished digging out the rubble and found the incredible 

depths of Lechuguilla Cave. 

Jim White, the first explorer and unofficial guide to the 

cave, later became a park ranger and advanced to chief 

ranger. He devoted his life to opening up an 

underground wonderland that is now enjoyed by nearly 

one million visitors from all over the world each year. 
 NPS Geologic Resources Division 4 

Figure 1. Location map of Carlsbad Caverns National Park. 
 CAVE Geologic Resource Evaluation Report 5

Figure 2. Major physiographic features of the Permian Basin during early Guadalupian time. Diagram from the New Mexico Institute of 

Mining and Geology, http://www.geoinfo.nmt.edu/staff/scholle/guadalupe.html#genset (access 2005). 
 NPS Geologic Resources Division 6 

A) 

Period Epoch Back Reef Strata Reef Strata Fore Reef and 

Basin Strata 

Rustler Fm Ochoa 

Castile Fm 

Tansill Fm 

Yates Fm 

Seven Rivers Fm 

Capitan Limestone Bell Canyon Fm 

Queen Fm 

Guadalupe 

Grayburg Fm 

Goat Seep 

Dolomite 

Cherry Canyon 

Formation 

Sandstone tongue of Cherry Canyon Fm 

PERMIAN 

Leonard San Andres Formation 

B) 

Figure 3. Schematic cross-section (A) and stratigraphic column (B) for Carlsbad Cavern National Park showing back-reef, reef, and 

fore-reef formations. Colored formations in (B) are present within Carlsbad Caverns . Thick black lines in (A) are surfaces of erosion. 
 CAVE Geologic Resource Evaluation Report 7

Geologic Issues 

A Geologic Resource Evaluation scoping session was held for Carlsbad Caverns 

National Park on March 6-8, 2001, to discuss geologic resources, to address the status of 

geologic mapping, and to assess resource management issues and needs. The following 

section synthesizes the scoping results, in particular, those issues that may require 

attention from resource managers. 

Significant geologic resources exposed both at the 

surface and in the caves pose geologic issues for the 

resource manager. Discussions during a one-day field 

trip, and the in-house scoping session, as well as from the 

Final General Management Plan/Environmental Impact 

Statement (GMP/EIS) identify the following geologic 

issues for Carlsbad Caverns National Park. 

Water Contamination 

Factors contributing to a relatively high vulnerability of 

Carlsbad Cavern National Park caves to contamination 

from the surface include: 1) the absence of a significant, 

continuous soil zone over the cave system, 2) the 

presence of localized but highly permeable fracture 

zones in the limestone, and 3) the presence of well 

developed karst. Most of the contaminants from parking 

lots are carried by the first 0.5 inch (13 mm) of rain. 

About 540,000 liters of contaminated water enters the 

groundwater system from parking lots in every 0.5 inch 

(13 mm) rainstorm. On average, there are 10 storms per 

year that produce more than 0.5 inch (13 mm) of rain 

(Bremer 1998). Therefore, at least 5.3 million liters of 

contaminated water enter the groundwater system every 

year (Burger and Pate 2001). 

Studies by Brooke (1996) and van der Heijde and others 

(1997) identified three major potential sources that could 

threaten both water quality in the cavern and public 

health: 1) leaks in the sewer lines; 2) contaminated runoff 

from spills and vehicle fires on public parking lots and 

road segments; and 3) spills, leaking tanks, fires, and 

other accidental releases from the maintenance yard. The 

most threatened areas identified by the study in Carlsbad 

Cavern were: Quintessential Right, Left Hand Tunnel, 

New Section, the Main Corridor between Devil’s Spring 

and Iceberg Rock, and locations in Chocolate High, the 

New Mexico Room, the Scenic Rooms, and the Big 

Room area (Van der Heijde et al. 1997). Infiltration in the 

vadose zone from the surface to the caves varies between 

4 to 10 years in the Main Corridor and 14 to 35 years in 

the Big Room. 

Infiltration research led to a re-evaluation of the 

infrastructure above the cave and proposals to change 

the management of cave and karst resources in the park 

(Burger and Pate 2001). Modifications of the developed 

area above Carlsbad Caverns were proposed in order to: 

1) protect groundwater and cave resources from 

continuing chronic exposure to contamination, 2) 

protect cave resources from potential catastrophic 

contamination, and 3) protect visitors to Carlsbad 

Caverns from potential hazardous conditions due to 

contamination. The park prepared an Environmental 

Assessment (EA) designed to reduce the impacts from 

park facilities on the cave. Recommendations included 

the following proposals (Burger and Pate 2001; Pate 

personal communication 2006). Plans are currently in the 

works to replace the main outfall sewer line, remove 

most of the Bat Cave Draw Parking Lot, and install oil & 

grit separators on remaining lots. These changes are 

slated for implementation in the next 1 to 3 years (Pate 

personal communication 2006). 

• Treat some of the runoff and eliminate some paved 

areas altogether. 

• Resurface parking lots near the visitor center so that 

they drain southward, away from the cave. 

• Install a storm water filtration system at drainage 

points for these parking lots 

• Close the large parking lot in Bat Cave Draw to reduce 

the amount of vehicle fluid buildup. The EA 

recommends removing most of this parking lot and 

replacing it with a bus turnaround area and 

handicapped access path to the natural entrance 

• Remove most of the paved surface and replace it with 

natural vegetation to help restore natural drainage and 

infiltration conditions. 

• Replace the sewage collection system in the housing 

and office area north of Bat Cave Draw with new lines. 

• Reroute the main sewage line southward to minimize 

the exposure of the caves to sewage leaks. 

Sewage line repair and restructuring of the parking lots 

are funding priorities for the park. Implementation of a 

space reallocation plan would remove most residents 

from above the cave thus reducing the amount of sewage 

in the system and the number of vehicles parked above 

the cave on the north side of Bat Cave Draw. 

Cave Preservation 

Several anthropogenic structures located within the 

subsurface may affect the amount and distribution of 

water infiltrating into and through the subsurface. Water 

percolating into the subsurface is redistributed by the 

extensive underground trail system and virtually 

impervious lunchroom area about 750 feet (250 m) below 

the visitor’s center (Van der Heijde et al. 1997). In the 

past, periodic cleaning of the trails released water into 

the surrounding caverns. Water lines along the trails are 

no longer in use but remain in the cave and could leak at 
 NPS Geologic Resources Division 8 

an unknown rate at connection points and at spigots if 

use was resumed (Brooke 1996; Pate personal 

communication 2006). In the past, runoff from trails was 

thought to contain rock fragments, organic compounds, 

and nitrates from urine on the trail (Van der Heijde et al. 

1997). However, trails in the cave are no longer washed 

so contaminated water is not released into the cave 

environment (Pate personal communication 2006). 

The elevator and utility shafts underneath the visitor’s 

center also provide major downward conduits for water 

infiltrating the upper formations (Brooke 1996). A 

sewage pump removes wastewater from the restroom 

facilities located within the lunchroom area through the 

utility shaft to the surface. Equipment failure or 

maintenance practices of these restroom and sewage 

transport facilities may result in contamination. 

Recognition of problems with the current pump and 

standpipe has prompted the park to request money for 

their replacement. However, the timeline for 

implementation of a new system remains uncertain (Pate 

personal communication 2006). 

More than 500,000 visitors a year enter Carlsbad 

Caverns. Food, chewing gum, litter, and lint have been 

found throughout the cavern. Discoloration of 

speleothems in Carlsbad Caverns results from large 

accumulations of lint, clothing fibers, dead skin, and hair 

left behind each year by thousands of cave visitors. The 

buildup of lint makes the speleothems appear dull and 

gray. Investigations show that lint is a very good source 

of organic material for microbes, mites, and spiders and 

that the breakdown of the lint may generate organic 

acids that dissolve calcite speleothems (Burger and Pate 

2001). 

Researchers found that short rock walls along the sides 

of the trail contain much of the lint. To reduce lint 

accumulations, rock walls have been and are continuing 

to be, built along the five-kilometer-long trail (Pate 

personal communication 2006). The trail is vacuumed 

twice a year to remove lint and a volunteer group works 

in the cave during an annual week-long “Lint Camp” to 

remove lint and other litter from along the visitor trail 

system. 

Formerly water was used to clean the floor in areas 

where there is a problem with visitors urinating in the 

cave and in places where the trail may become slick 

(Burger and Pate 2001). However, runoff from this 

cleaning method was problematic and as a result a new 

method of cleaning has been adopted. The new method 

of cleaning problem areas involves applying a bleach 

solution that is then covered with an absorbent material 

and removed from the cave. This has eliminated the 

presence of contaminated runoff from trail cleaning in 

the cave (Pate personal communication 2006). 

Speleothem breakage monitoring between 1985 and 1991 

revealed that as many as 2,000 speleothems annually 

were vandalized or stolen. Measures taken to correct this 

problem included the addition of stainless steel railings 

along both sides of the paved trail through the selfguided portions of the cave. During the installation of the 

railings from 1997 to 2000, monitoring showed that 

visitors leaving the trail system declined significantly. 

This monitoring also appeared to show a significant slow 

in vandalism to speleothems. Nevertheless, vandalism 

remains a concern and an ongoing problem for resource 

management (Pate personal communication 2006). 

Lights in the cavern create an environment that allows 

algae, moss, and fungus to grow. The lights also draw 

animals farther into the cave than they would normally 

venture. These factors impact and change the cave 

environment. 

Although entry to Lechuguilla Cave requires a permit, 

exploration and research have resulted in some adverse 

impacts to pristine cave resources. In 1996 it was 

documented that opening the lid to the airlock-culvert 

system allowed small dirt and debris particles to fall into 

the cave, and created a blast of air that was thought to 

affect cave conditions. The installation of a stainless steel 

access tube with an airlock system has corrected the 

problems associated with debris and airflow at the 

entrance (Pate personal communication 2006). 

Expeditions requiring several days are necessary to 

explore and precisely document new areas, but 

exploration, recording expeditions, and careless travel 

have damaged numerous formations. Many delicate and 

once pristine formations adjacent to travel routes are 

covered by mud and dirt. The park has addressed this by 

implementing more stringent guidelines, including the 

requirement that minimum impact caving techniques be 

used when working in the cave. This action has led to 

better overall protection of cave resources. In addition 

restoration activities have also corrected some of the 

more serious impacts (Pate personal communication 

2006). 

Human urine also impacts the cave environment (NPS 

1996). For safety and ultimately the protection of cave 

resources, urine is allowed to be placed in designated 

locations in the cave when expeditions require more 

than two days. This remains one of the more serious 

impacts to the cave environment despite various 

researchers’ efforts to solve this difficult problem (Pate 

personal communication 2006). 

As of 2006, 113 caves are known in the park. Although, 

cave resources in the backcountry are not being fully 

monitored, there is little evidence of vandalism and theft 

of cave resources. 

Several caves outside the park boundary on U.S. Forest 

Service (USFS) and Bureau of Land Management (BLM) 

lands might connect to pristine park caves such as 

Lechuguilla and possibly other undiscovered caves (NPS 

1996). Many water sources that are integral to the 

formation of the caves and ecosystem in the park also 

originate outside the park boundary. 

Water Supply and Rattlesnake Springs 

Rattlesnake Springs lies south of Guadalupe Ridge, about 

5 miles (8 km) from the mouth of Slaughter Canyon, and 
 CAVE Geologic Resource Evaluation Report 9

is the sole water supply source for Carlsbad Caverns 

National Park. It also provides a vital wetland habitat 

that supports several species of threatened birds and fish. 

In 1948, the National Park Service became concerned 

about aquifer contamination when agricultural 

development began. There is evidence showing that an 

aquifer adjacent to the one that supplies water to 

Rattlesnake Springs has been contaminated by oil and 

gas activities and that high flow conditions spill this 

contaminated water over into the Rattlesnake Springs 

drainage area (Pate personal communication 2006). A 

nearby gas field produces from the Morrow Formation 

(Pennsylvanian), the most important natural gas 

producer in the Delaware Basin of southeastern New 

Mexico (Mazzullo and Brister 2001). If there is a breach 

in the casing, a loss of circulation, or another drilling 

problem, the result could be contamination of one or 

more of the aquifers that supply water to the park and 

surrounding landowners. Because of these concerns, the 

National Park Service sponsored a study of the aquifer 

supplying Rattlesnake Springs (Bowen 1998). 

Rattlesnake Springs is a high-discharge artesian spring 

that flows from a karstic, well-indurated limestone 

conglomerate located at the distal end of a small alluvial 

wedge between the Gypsum Plain of the Delaware Basin 

and the Guadalupe Reef Escarpment. The conglomerate 

is derived from the large alluvial fan emanating from 

Slaughter Canyon and is either Miocene-Pliocene or 

Pleistocene in age (Bowen 1998). 

The limestone conglomerate lies above the Castile 

Formation, a regional confining layer, or aquitard. The 

low conductivity of the Castile is due to the presence of 

evaporites that have some of the lowest conductivity of 

any natural media (2x10-8 to 4x10-13 m/sec). 

Based on hydrologic data, Bowen (1998) hypothesized 

that flow within the Slaughter Canyon alluvial fan “is 

controlled by karst channels within the limestone 

conglomerate.” The heterogeneity of the system localizes 

flow within channels and isolates the conglomerate 

between finer silt- and clay-dominated sediments. 

Karstic channels produce mostly isolated, discrete flow 

paths, and these flow paths need to be identified for the 

Slaughter Canyon area. An electrical survey (ground 

penetrating radar) could be used to identify the channels. 

Bowen (1998) concluded that contamination of 

Rattlesnake Springs was not likely to occur from the 

nearby Washington Ranch natural gas injection facility. 

Furthermore, current agricultural withdrawals from the 

system appeared to have minimal impact on Rattlesnake 

Springs. Bowen cautioned, however, that future 

developments of the upper Black River Valley “could 

have significant impacts on the system due to the karstic 

nature of flow” (Bowen 1998). 

The NPS has recently funded a group out of the 

University of Texas at El Paso to accurately determine 

the location of the discreet channel (or channels) that 

feed Rattlesnake Springs. Once determined, any future 

drilling for oil & gas can be directed away from this (or 

these) channels (Pate personal communication 2006). 

Water flow in the park’s backcountry springs and seeps 

has been monitored on an annual basis since the early 

1960s. At that time 10 permanent springs, 12 permanent 

seeps, and 6 intermittent seeps were recorded. About 

half of these water sources were developed for early 

ranching and guano mining operations. Remnants of 

earthen and metal tanks, check dams, and catchment 

basins still exist. In 1993, 47 seeps and springs were 

inventoried in the park. About 20 of these are permanent 

water sources considered critical to wildlife. 

Mineral Resources 

Oil and Gas 

Under federal law, no federal mineral or oil and gas 

leasing or the associated development is permissible in 

Carlsbad Caverns National Park. In addition, provisions 

in the Lechiguilla Cave Protection Act, the record of 

decision by the Bureau of Land Management with regard 

to the Bureau’s Dark Canyon Environmental Impact 

Statement (establishing an 8,320-acre cave protection 

area north of Carlsbad Caverns National Park in the 

vicinity of Dark Canyon), and the USFS management 

action provide protection for many cave resources. 

However oil and gas are produced on state lands, and 

exploration and production on unrestricted state and 

private lands has the potential to irreparably alter or 

destroy cave resources in Carlsbad Caverns National 

Park. 

The Lechuguilla Cave Protection Act (Public Law 103-

169) gives additional protection to Lechuguilla Cave and 

other cave resources in and near the park by establishing 

a 9,720-acre cave protection area (NPS 1996). The act 

withdraws 6,280 acres of adjacent federal lands from 

mineral exploration and development and prohibits new 

drilling. However, the act does not apply to the 960 acres 

of adjacent private lands or 2,880 acres of state-owned 

lands within the cave protection area. Protective 

measures in the Lechuguilla Cave Protection Act include: 

• Prohibiting occupancy on existing federal leases 

• Canceling existing federal leases where necessary 

• Prohibiting additional drilling on federal leases 

• Limiting surface access to all federal leases in the cave 

protection area 

During the summer of 2006 the State of New Mexico 

issued oil and gas leases on five sections of land 

approximately two miles north of the park boundary. 

These five sections of state land lie within the 9,720 acre 

cave protection area. No wells have been drilled in this 

state lease area at the time of this writing. Additional 

leasing on state and private lands north of the park 

remains a possibility. The NPS is trying to initiate a 

dialogue with the state of New Mexico to address park 

protection concerns. 
 NPS Geologic Resources Division 10 

Since the 1920’s, hydrocarbon exploration has been 

active south of Carlsbad Caverns National Park in the 

Delaware Basin, a sub-basin of the larger Permian Basin. 

About 71 percent of Permian Basin oil (65 billion barrels) 

and 54 percent of Permian Basin associated and 

dissolved gas-in-place (0.93 trillion cu m; 32.7 trillion cu 

ft) have been produced from Permian-age strata. The 

remainder (mostly gas) is produced from Pennsylvanian 

or older Paleozoic rock, predominantly from the 

Ordovician Ellenburger Formation (Table 1) (Ward et al. 

1986; Hill 1996). 

TABLE 1: Producing units in the Delaware Basin 

Period Formation Oil/Gas 

Permian 

Tansill Fm 

Yates Fm 

Seven Rivers Fm 

Queen Fm 

Grayburg Fm 

Bell Canyon Fm 

Cherry Creek Fm 

Brushy Canyon Fm 

San Andres Fm 

Abo-bone Spring 

Wolfcamp Fm 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Oil 

Pennsylvanian 

Cisco Fm 

Canyon Fm 

Strawn Fm 

Atoka Fm 

Morrow Fm 

Oil 

Oil 

Gas 

Gas 

Gas 

Devonian Woodford Fm Gas 

Silurian Fusselman Fm Gas 

Ordovician Montoya Fm 

Ellenburger Fm 

Gas 

Gas 

(From Hill (1996) and the Texas Bureau of Economic Geology, 

access 2005) 

The largest producers of oil in the Delaware (and 

Permian) Basin are the Guadalupian-age reservoirs of the 

Queen, Seven Rivers, Yates, and Tansill Formations 

(figure 3) (Ward et al. 1986; Hill 1996; New Mexico 

Institute of Mining and Technology 2005). Together, 

they account for 67 percent of all Permian oil found and 

62 percent of all Permian gas found in the Delaware 

Basin. The second most prolific Permian reservoirs are 

found in Leonardian strata such as the open-shelf San 

Andreas Limestone (figure 4). Most of the production 

from Permian rocks comes from less than 5,000 feet 

(1,500 m) (Dolton et al. 1979). 

Hydrocarbon traps in Permian rocks are mostly a 

combination of stratigraphic and structural traps with 

the hydrocarbons sealed in place by porosity and 

permeability barriers of carbonate, evaporite, or shale. 

Production is maximized in the near-back-reef or 

grainstone margin facies that was neither cemented like 

the reefs nor plugged with evaporite cement like backreef strata closer to shore. Back-reef environments 

account for more than 90 percent of all hydrocarbon 

production in the Delaware Basin (figure 4). 

No production comes from the Capitan, Victorio Peak, 

or Goat Seep reef or fore-reef facies. These rocks were 

tightly cemented on the sea floor shortly after deposition 

(New Mexico Institute of Mining and Technology 2005). 

Basin sediments account for the rest of the production. 

Hydrocarbons are trapped in submarine channel 

sandstones and basinal limestones of the Delaware 

Mountain Group (Bell Canyon, Brushy Canyon, and 

Cherry Canyon Formations) (Berg 1979; Williamson 

1979; Hill 1996; Texas Bureau of Economic Geology 

2005). The submarine channel sandstones pinch out 

against the Capitan reef complex. 

Most of the Permian oil is generated from the largely 

organic, carbon-rich, basinal sediments such as the Bone 

Spring Limestone. Oil in basinal facies has probably 

migrated only a short distance from source to reservoir. 

Oil in back-reef facies, however, moved up-section or 

laterally through fractured reef sediments to get from 

source to reservoir. Although cementation destroyed 

reef porosity, permeability through the reef zone was 

high due to fracturing of the reef. 

Current estimates suggest that 1.0 to 6.0 billion barrels of 

oil in-place remains to be discovered in Permian rocks of 

the Permian Basin (New Mexico Institute of Mining and 

Technology 2005). This volume is 1.5 to 9.2 percent of 

the discovered Permian Basin crude oil. 

Deeper, pre-Permian hydrocarbon (mostly gas) 

accumulations are found in the Delaware Basin and on 

the Central Basin Platform. Most of the gas is found in 

structural, stratigraphic, or combination traps that are 

sealed by shale and impermeable carbonate rocks (Hill 

1996). Some Pennsylvanian reservoirs are found near 

Carlsbad, New Mexico, northeast of the park, but none 

extend past the northwest-southeast trending Huapache 

Monocline that intersects the Capitan reef between 

Rattlesnake Canyon and Carlsbad Caverns (Hill 1987, 

1996). The lowermost Pennsylvanian gas reservoir is in 

the Morrow Formation, about 10,000 feet (3,050 m) 

beneath Carlsbad Caverns (NPS 1996). 

Hundreds of producing gas and oil wells have been 

drilled north, east, and south of Carlsbad Caverns 

National Park (figure 4). Exploratory wells have been 

drilled within a few thousand feet of the north and east 

boundaries of Carlsbad Caverns, and some of these have 

encountered voids at the same depth as major passages in 

Lechuguilla Cave (NPS 1996). At least 61 wells drilled 

near the park have encountered lost circulation zones in 

the Capitan and Goat Seep Formations, suggesting that 

unexplored cave passages were intersected during 

drilling (NPS 1993, 1996). 

Substantial hydrocarbon reserves and known cave 

resources exist immediately north of the park boundary. 

It is probable that exploratory drilling will intersect 

openings that connect with caves in the park. Resources 

inside the park could be at risk of contamination from 

toxic and flammable gases and other substances 

associated with the exploration production of oil and 

gas. 
 CAVE Geologic Resource Evaluation Report 11

In 1993, the National Park Service convened a panel of 

geologists familiar with caves and geology in the 

Carlsbad region to consider the various risks of 

contamination to caves within the park from 

hydrocarbon exploration and production (NPS 1993). 

The principal conclusion of the panel was that there was 

no way to protect the cave resources of Carlsbad Caverns 

without establishing a cave protection zone along the 

northern boundary. 

More detailed information about hydrocarbon reserves 

and oil and gas production potential in the Carlsbad 

Caverns area is given in the Final Dark Canyon 

Environmental Impact Statement (BLM 1993) and 

“Report of the Guadalupe Caverns Geology Panel to the 

National Park Service” (NPS 1993). More detailed 

information on the oil and gas resources of the Delaware 

Basin is available from the oil and gas atlases of the Texas 

Bureau of Economic Geology in Austin, Texas 

(http://www.beg.utexas.edu/, access 2005), and the New 

Mexico Bureau of Mines and Mineral Resources in 

Socorro, New Mexico (http://geoinfo.nmt.edu/, access 

2005). 

Sulfur 

Sulfur deposits in the Delaware Basin formed in 

sedimentary rocks by the secondary oxidation of H2S in 

groundwater. There are two primary sulfur producing 

areas in the Delaware Basin: the Rustler Springs sulfur 

district just south of Carlsbad Caverns National Park and 

the Fort Stockton sulfur district on the southeast edge of 

the Delaware Basin adjacent to the Central Basin 

Platform (Hill 1996). Sulfur also occurs on the 

Northwest Shelf and in the caves of the Guadalupe 

Mountains. 

Sulfur has been reported in Carlsbad Cavern and 

Lechuguilla Cave (Hill 1987; Cunningham et al. 1993). 

Minute amounts of sulfur in Carlsbad Cavern were 

reported in the Big Room, Christmas Tree Room, and 

New Mexico Room. In the Big Room, sulfur occurs as an 

overgrowth crust lining a drip tube in a gypsum block. 

However, investigators found that some of the material 

thought to be sulfur was actually the yellow uranium 

minerals, tyuyamuite or metatyuyamunite (Cunningham 

et al. 1994; Hill 1996). 

Lechuguilla Cave hosts more sulfur than all the other 

caves in the Guadalupe Mountains combined (Hill 1996). 

Multi-ton deposits exist in the North and South Ghost 

Town areas and in the Void. The sulfur has a massive, 

microcrystalline, conchoidal, or vuggy texture. Ghost 

Busters Hall, the Rift, the FLI Room, Hard Daze Night 

Hall, Chandelier Graveyard, and Southwest Branch and 

Far East sections of the cave are also reported to have 

sulfur deposits (Cunningham et al. 1993; Hill 1996). 

Sulfide, Barite, and Fluorite deposits: 

Deposits of various sulfides, barite (BaSO4), and fluorite 

(CaF2) are found around the margin of the Delaware 

Basin in the Guadalupe, Apache, and Glass Mountains 

and in the Fort Stockton area. The mineral deposits are 

small and of low economic potential. The mineral 

deposits in the Apache and Glass Mountains are more 

extensive than in the Guadalupe Mountains. 

In Carlsbad Caverns, barite has been found at several 

locations within the entrance pit of Lechuguilla Cave 

(Hill 1996). The entrance lies along a flexure 

superimposed on the southeastern flank of the 

Guadalupe Ridge anticline. The barite occurs in the 

Seven Rivers Formation as an intergrowth with calcite. 

Potash 

Potash in an informal term usually meaning potassium 

oxide (K2O) or potassium carbonate (K2CO3), but it may 

also include a variety of potassium minerals such as 

chlorides, sulfates, and nitrates with substitutions by 

magnesium, calcium, and sodium. Encompassing an area 

of approximately 1,160 square miles (3,000 square km) 

about 15-25 miles (25-40 km) east and northeast of 

Carlsbad in Eddy County, the Carlsbad Potash district 

contains some of the world’s major potassium deposits 

(Hill 1996). At one time, the district supplied about 85 

percent of domestic potash production. 

Potash minerals occur entirely within the Salado 

Formation. The Salado Formation was deposited over 

the Capitan Limestone reef complex, but, in the park 

area, has since been removed by erosion (figure 3). Only 

a few deposits have been found outside of the district but 

are not economic. 

Miscellaneous Deposits 

Selenite, a clear, colorless variety of gypsum, has been 

found in the Castile Formation, especially along the small 

faults in the southwestern part of the East Quadrangle 

(Hayes 1974). Vast amounts of fine-grained gypsum 

occur in many areas. Limestone gravel suitable for road 

ballast has been quarried in the past. Limestone and 

dolomite from the Tansill, Yates, and Seven Rivers 

Formations have been used in the construction of the 

buildings at the park (Hayes 1974). 

Paleontological Resources 

For many years, geologists have visited an outcrop in 

Walnut Canyon for excellent exposures of the reef and 

near-back-reef facies of the upper Capitan Limestone 

and Tansill and Yates Formations (described in the 

“Geologic Features” section). Testing the limestone with 

hydrochloric acid has etched the outcrop and 

serendipitously exposed many of the marine organisms 

in the reef. Although fossils occur throughout the park, 

many geologists recognize the excellent reef exposure in 

Walnut Canyon as world-class and deserving of special 

protection. Preservation efforts could model those taken 

at Dinosaur National Monument to preserve and protect 

Jurassic dinosaur bones. 

Bats and Bat Habitat Management 

In summer evenings, about 5,000 bats per minute exit the 

entrance to Carlsbad Caverns. This evening exodus may 

last for up to 2 hours. In the early 1900s, an estimated 8 

or more million bats were counted at Carlsbad Cavern, 
 NPS Geologic Resources Division 12 

but today, only about 300,000 bats (mostly Mexicanfreetail bats) use the cave. 

There were several very large bat counts in the 1900s, 

however there are no records of the method by which 

these numbers were derived therefore they are of 

questionable scientific value. Although the exact 

numbers are unsure it is certain that bat populations have 

declined due to past mining activities, loss of habitat to 

the expanding human population, and the use of 

chemicals, especially DDT. 

In the 1950s and 1960s. DDT was banned in the United 

States in 1972, but there is no such ban in Mexico, where 

the bats spend the winter. In 1994, a large quantity of 

illegal and improperly stored, DDT was discovered in a 

shed near the park. This may have contributed to the 

higher levels of DDT residue in the Carlsbad bats relative 

to bats in other parts of the country. Two shafts sunk by 

miners before 1923 also contributed to a bat population 

reduction. The shafts allowed warm air near the ceiling 

to escape so that the survival of bat pups in the maternity 

colony was made more difficult. The National Park 

Service plugged these shafts in 1981. Bat populations rose 

to 750,000 in the mid-1990s (Kiver and Harris 1999). 

Bats are the only flying mammal in the world and one of 

the only night predators of insects. These gentle, insect 

eaters may consume up to 600 mosquitoes per hour and a 

lactating female can eat over half her weight in insects on 

her nightly forage. Bats from Carlsbad Cavern National 

Park are known to eat mostly moths, a significant portion 

of which are major pests on crops found along the Pecos 

and Black Rivers. Bats are at the top of the food chain 

and thus, are susceptible to increased levels of chemical 

pollutants that concentrate in lower plants and animals. 

The relationship between the bats, the geology of the 

caves, and the external environment is a delicate one and 

accentuates the need for ecosystem management beyond 

the borders of the park. 

Microbes and Lechuguilla Cave 

Previously unknown bacteria have been found living on 

rocks and in pools of Lechuguilla Cave. Surviving 

hundreds of meters below the ground with no light and 

no organic input from the surface, these bacteria line the 

walls, ceiling, and floors of many places in Lechuguilla 

Cave (Burger and Pate 2001). The pools in Lechuguilla 

Cave are also teeming with life competing for the few 

nutrients that exist. On the medical front, enzymes 

released by the bacteria have been found to attack 

leukemia cells. 

Unfortunately, human exploration introduces foreign 

bacteria into the cave on skin, hair, and clothing fibers. 

These bacteria out compete native microbes for food and 

destroy their populations. To address this problem the 

park has instituted a policy requiring that everyone who 

enters Lechuguilla Cave has clean clothes and clean 

equipment, thus preventing the introduction of microbes 

from other caves into Lechuguilla. Cave explorers also 

are required to eat and sleep on drop cloths to catch 

food, skin, and hair. They are encouraged to wear 

bandanas to contain hair and are required to eat their 

food over plastic bags to catch falling crumbs. 

In addition, cavers are restricted from getting near any 

pools found during exploration. When a pool is 

discovered, it is reported to the park and to scientists 

studying the microbes. Scientists approaching the pools 

wear Tyvek clean suits and set up slides that sit in the 

cave for up to five years. When the slides are collected, 

the bacteria are cultured in a lab and studied further 

(Burger and Pate 2001). Discoveries such as these are 

significant and demonstrate the need to protect similar 

natural areas for further research into the microbes and 

their environment. 

Guides and Maps for Interpretation 

Printed geologic trail guides are needed for the general 

public. The guides would also be an aid to the 

interpretive staff. 

Springs associated with the Yates Formation-Tansill 

Formation contact are the most important water supply 

for animals in the park. Paul Burger, park geologist, 

expressed the need to map these springs for all 7.5 

minute quadrangle maps (Appendix B). He also 

expressed a need for geo-habitat maps that associate 

wildlife habitat with geology, especially for endangered 

species (Appendix B). There has been no known interest 

in mapping the surface geology of the park since the 

1960s. 

Carlsbad Caverns National Park Planning Documents 

The 1996 GMP, the 1995 Cave Management Plan (CMP), 

and the 1994 Resources Management Plan and 

Environmental Assessment (RMP) developed programs 

for the study, protection, exploration, surveying, and 

monitoring of cave resources. The major programs in 

these plans are summarized below. Details of each plan 

may be found in the appropriate document.

Subsurface Resources 

The GMP proposes methods to reduce cave resource 

impacts, including ways to keep people from touching or 

breaking cave formations and spreading lint from their 

clothing. The 1993 Lechuguilla Cave Protection Act and 

the BLM Final Dark Canyon Environmental Impact 

Statement (1993) address cave resources north of the 

park boundary. The Park Service cooperates with the 

BLM and the State of New Mexico to mitigate impacts 

on cave resources within the park’s boundary and 

outside of the park from drilling activities outside of the 

park boundaries. 

The actions that are proposed in the GMP regarding 

subsurface resources include the following: 

• No construction of new buildings or impervious areas 

(e.g., paved parking lots) above the cavern or other 

cave resources; 

• Install catchment basins in parking lots to trap 

petroleum byproducts washed off pavement; 

• Evaluate the infiltration hazard study; 
 CAVE Geologic Resource Evaluation Report 13

• Continue to limit visitor access in the Green Lake 

Room, King’s Palace, Queen’s Chamber, and Papoose 

Room to protect the fragile cave resources; 

• Increase NPS staff and deploy them more effectively to 

protect cave resources; 

• Emphasize the significance of resources in interpretive 

messages; 

• Implement actions to reduce the impacts of trails on 

Carlsbad Caverns, including surface material and trail 

cleaning methods; 

• Redesign the trail lighting system to make it more 

efficient and easier to maintain and to minimize 

associated algal growth; 

• Prioritize research, exploration and mapping needs for 

Lechuguilla Cave and ensure compatibility with NPS 

research guidelines and management needs and 

priorities; 

• Evaluate possible improvements to the present 

Lechuguilla Cave airlock-culvert system; 

• Develop a plan for the restoration and rehabilitation of 

Lechuguilla Cave resources; 

• Provide funding and staffing to enforce existing 

guidelines for exploring and surveying all park caves; 

• Protect paleontological resources during cave 

restoration projects; and, 

• Develop a feasibility study to determine if Ogle Cave 

could be opened for guided tours similar to the tours 

given at Slaughter Canyon Cave. 

The recommendations in the RMP and CMP are 

consistent with those in the GMP. They include: 

• Preserve and perpetuate natural cave systems while 

providing opportunities for public education, 

recreation, and scientific study; 

• Keep Lechuguilla Cave closed to the general public 

because of its hazardous nature, unique resources, 

research potential, and continuing exploration and 

survey; 

• Inventory and monitor all caves designated for 

regulated public access; 

• Provide information packet for visitors to wild caves; 

• Photo-monitor caves designated for recreational 

visitor entry; 

• Study water infiltration patterns to better understand 

and mitigate human-induced changes in the cave 

ecosystem; and, 

• Implement a cave rehabilitation program to offset the 

alteration of the natural cave environment from over 

50 years of intensive human use. 

Surface Resources: 

The GMP proposes a cooperative plan with Guadalupe 

Mountains National Park and the Waste Isolation Pilot 

Project (WIPP site) to monitor air quality in the vicinity 

of the park. The GMP also proposes to work 

cooperatively with the state of New Mexico to address 

water quality issues and to update the emergency flood 

response plan for flood-prone areas such as Walnut 

Canyon and Slaughter Canyon. 

To protect fossil resources, the GMP proposes evening 

patrols of the park entrance road to discourage illegal 

collecting of fossils. Paleontological resources would be 

inventoried and analyzed. Old and new data is to be 

incorporated into the Smithsonian Institution’s 

nationwide FAUN-MAP system. 

The plan calls for a study of groundwater flow associated 

with Rattlesnake Springs and an inventory and 

monitoring of backcountry springs affected by humanmade impoundments. The 1989 Rattlesnake Springs 

Management Plan and the 1982 Water Resources 

Management Profile also address water resource 

protection for the park.
 NPS Geologic Resources Division 14 

 

Figure 4. Inferred distribution of depositional facies in the lower Guadalupian strata (A) and upper Guadalupian strata (B) of the 

Permian Basin. Oil and gas fields producing from those intervals are also shown. Dashed line in (A) represents line of zero net

porosity. Diagrams from the New Mexico Institute of Mining and Geology, http://www.geoinfo.nmt.edu/staff/scholle/guadalupe.html# 

genset (access 2005) and Ward and others (1986). 
 CAVE Geologic Resource Evaluation Report 15

Geologic Features and Processes 

This section provides descriptions of the most prominent and distinctive geologic features 

and processes in Carlsbad Caverns National Park. 

The surface and cave features in the Guadalupe 

Mountains are the result of geologic forces, climate 

changes, and the action of water over a vast span of time. 

The caves in Carlsbad Caverns and in Guadalupe 

Mountains National Park are the result of a process of 

dissolution involving sulfuric acid. Decorations in these 

caves are arguably unsurpassed in the world. On the 

surface, Carlsbad Caverns NP and the surrounding 

Guadalupe Mountains provide a unique window to the 

world’s best outcrops of a preserved ancient reef where a 

250-million-year geologic story is exceptionally exposed 

in the desert landscape. The Capitan Reef continues to 

offer exceptional potential for additional cave discovery, 

exploration, and research (NPS 1996). 

Formation of Carlsbad Cavern 

There are 113 known caves within Carlsbad Caverns 

National Park and most of them reveal the unusual mode 

of origin by sulfuric acid (H2SO4). Most of the world’s 

limestone caves are created when surface water flows 

down through cracks in limestone and slowly enlarges 

passageways. Surface (meteoric) water contains 

dissolved carbon dioxide forming a weak acid called 

carbonic acid. This acid slowly dissolved the rock in 

more than 90 percent of the world’s limestone caves. 

These types of caves are typically very wet and have 

streams, rivers, and sometimes lakes or large waterfalls. 

They are part of the local or regional drainage system 

that transports surface water to the sea. This process 

formed the caves in Mammoth Cave National Park and 

Buffalo National River in the Ozarks, but not Carlsbad 

Caverns National Park. There are no flowing streams in 

any of the hundreds of caves in the Guadalupe 

Mountains. 

About 60 million years ago, during a major episode of 

mountain building known as the Laramide Orogeny, the 

central part of New Mexico and Colorado was uplifted, 

forming a major, north-trending arch known as the 

Alvarado Ridge. This ridge extended from Wyoming to 

west Texas and had a maximum elevation in central and 

southern New Mexico of about 12,000 ft (3,650m). 

Water in limestone aquifers moved down the east slope 

of the Alvarado ridge toward Texas, and some of that 

water flowed through limestones of the Capitan Reef. 

This water had significant hydrostatic head (pressure) 

which forced it upward along fractures in the Capitan 

Limestone to spring outlets scattered through the 

ancestral Guadalupe Mountains. As water moved 

upward through the fractures, it dissolved limestone and 

formed vertically oriented fissure caves. About 30 million 

years ago, in Late Oligocene to Early Miocene time, uplift 

culminated in faulting associated with the opening of the 

Rio Grande Rift along the axis of the Alvarado Ridge. 

Erosion gradually exhumed the Capitan Reef, and 

coupled with faulting along the rift, caused the water 

table to fall. As the water table dropped, fracture caves 

became partly air-filled, allowing space for hydrogen 

sulfide to degas into the atmosphere. Hydrogen sulfide 

was derived from the microbially assisted alteration of oil 

and gas and gypsum in oil fields adjacent to the 

Guadalupe Mountains and is widely distributed in deep 

groundwater. Once in the cave atmosphere, hydrogen 

sulfide was rapidly reabsorbed into oxygen-rich water 

percolating downward from the surface. Mixing of 

hydrogen sulfide and oxygen in an aqueous environment 

produced in the sulfuric acid that dissolved limestone 

and formed the immense passages and galleries 

characteristic of Guadalupe Mountain caves. Because the 

Guadalupe Mountains are tilted eastward, the locus of 

sulfuric acid dissolution migrated eastward with time 

(DuChene and Cunningham 2006). Consequently, the 

oldest caves (about 12.5 million years) in the Guadalupes 

are in the west, and they become progressively younger 

to the east (3.8 million years at Carlsbad Cavern) (Polyak 

et al. 1998) (figure 5). 

One of the clues, which led geologists to the sulfuric acid 

hypothesis, is the presence of gypsum (CaSO4.2H2O) in 

many caves. Gypsum is produced by the reaction of 

sulfuric acid with limestone (CaCO3). Gypsum is a soft 

white mineral that coats walls, and forms crystals in some 

of the caves. Massive deposits of gypsum in the Big 

Room past the Bottomless Pit and at numerous locations 

in Lechuguilla cave attest to the large amount of sulfuric 

acid required to dissolve the immense rooms of Carlsbad 

Caverns and other caves in the Guadalupe Mountains. 

As dissolution of limestone progressed, support for the 

cave ceilings was reduced so that ceiling blocks tumbled 

to the floors of caves. Boulder-size blocks are common, 

but the largest of them is the massive Iceberg Rock in 

Carlsbad Cavern that weighs over 200,000 tons (Kiver 

and Harris 1999). Ceiling breakdown and roof collapse is 

one hypothesis for the creation of the entrance to the 

surface (Kiver and Harris 1999). An alternative 

hypothesis, however, suggests that the entrance to 

Carlsbad Caverns is a former spring outlet that was fed 

by water ascending through a tube developed along 

fractures that extended deep into the Capitan Limestone 

(Palmer and Palmer 2000). 

Speleothems 

Many of the speleothems (cave formations) that 

continue to grow and decorate Carlsbad Cavern are a 

result of rain and snowmelt percolating through the 

Capitan Limestone. Surface water contains dissolved 

carbon dioxide, which makes it slightly acidic and 

capable of dissolving limestone. Eventually, water 

saturated with calcium carbonate seeps and drips into 

the cave where loss of carbon dioxide causes calcite to 

precipitate as speleothems. 
 NPS Geologic Resources Division 16 

Many cave parks contain the stalactites, stalagmites, 

columns, flowstone, and helictites that are common in 

Carlsbad Caverns. However, the park is world famous 

because of the abundance and variety of common 

speleothems, and the presence of rare and exotic 

speleothems, especially in Lechuguilla Cave. Hanging 

from the ceiling in Lechuguilla Cave are glittering white 

gypsum chandeliers 15 to 20ft (4.5 – 6m) long, walls 

encrusted with aragonite ‘bushes’, and rippling strands of 

delicate ‘angel hair’ crystals that may reach 30 feet (9 m) 

long (Cahill and Nichols 1991). 

In the Kings Bell Cord in the Kings Chamber in Carlsbad 

Caverns, extremely delicate soda-straw stalactites that 

usually grow to a few inches in length, grow to 6 feet (1.8 

m) in length. In Lechuguilla, soda-straw stalactites reach 

18 feet (5.5 m) in length. 

Stalagmites that grow to immense size are called domes. 

Giant Dome in the Hall of Giants is 50 feet (15 m) tall. 

Crystal Springs Dome is one of the few speleothems still 

growing in Carlsbad Cavern. A thin film of new calcite 

forms on the surface of the dome as groundwater, 

saturated with dissolved calcium, drips onto the dome 

and carbon dioxide escapes into the cave atmosphere. 

The growth rate for Crystal Springs Dome is estimated to 

be equal to the thickness of a coat of paint added every 

90 years. The size of these speleothems is even more 

remarkable considering that many grow in a stop and 

start process rather than a continuous process. 

Caves in Carlsbad Caverns National Park also contains 

subaqueous minerals and speleothems. Elongate calcite 

crystals (‘dogtooth spar’) coat some cave walls and one 

pool in Lechuguilla has clear crystals of selenite 

(gypsum). Cave pools, many now mostly or completely 

dry, contain calcite crystals and “pool fingers” that 

formed under water. Large rounded forms called 

mammilaries, or “cave clouds” record a time when water 

filled the cave. 

Helictites, distorted twig-like lateral projections of 

calcium carbonate, remained a mystery to speleologists 

for many years. Mineralogists discovered a microscopic 

opening in the center of the helictites that allowed water 

to move upward by capillary action. Excellent examples 

of helictites can be seen in the Queen’s Chamber of 

Carlsbad Cavern. 

In Lechuguilla Cave, formations similar to conventional 

helictites were discovered in pools where they are 

developing under water. Rather than capillary forces, 

another process known as the “common ion effect” 

probably formed these features. The pool contains water 

saturated with calcium carbonate, and it is constantly 

resupplied with water percolating downward from the 

surface. Some of this water passes through deposits of 

gypsum located near the pool, dissolving calcium sulfate 

in the process. This water, which is saturated with 

calcium sulfate, flows into the pool. This results in the 

pool water near the point of influx becoming 

supersaturated with calcium, which then precipitates to 

form the worm-shaped speleothems known as 

subaqueous helictites (Davis et al. 1992; Kiver and Harris 

1999). 

Park Caves 

Carlsbad Cavern

Carlsbad Cavern is one of the world’s largest caverns by 

volume. It also is considered to be one of the most 

adorned with speleothems. The paved trail drops about 

830 feet (250 m) from the natural entrance through the 

Main Corridor into the King’s Palace area, which 

includes the Green Lake Room, the King’s Palace, the 

Queen’s Chamber, and the Papoose Room. 

Approximately 750 feet (225 m) below the visitor center, 

the trail inclines upward to the elevator area (NPS 1996). 

The cross-shaped Big Room measures 1,800 feet (550 m) 

in length, up to 1,100 feet (336 m) wide, and 255 feet (69 

m) at its highest point. Various world-renowned 

speleothems include the Whale’s Mouth, the Temple of 

the Sun, Giant and Twin Domes in the Hall of Giants, the 

Lion’s Tail, Painted Grotto, and Green and Mirror Lakes 

(figure 6). 

Lechuguilla Cave 

Lechuguilla Cave is about 4 miles (6.5 km) north of the 

Carlsbad visitors center. It is the deepest known 

limestone cave in the United States and contains some of 

the most spectacular formations in the world. Some of 

these include subaqueous helictites found nowhere else, 

rare hydromagnesite (magnesium carbonate) balloons, 

20-foot-long (6 m) gypsum chandeliers and gypsum 

hairs, 15-foot-long (4.5 m) soda straws, and unusual 

gypsum crystals, flowers, and crusts. The volumes of air 

entering and leaving the cave during periods of 

barometric change outside indicate that much of the cave 

is still unexplored. 

Rare chemosynthetic bacteria and obligate fungi, which 

derive energy from gypsum, magnesium, and iron 

deposits, have been discovered in Lechuguilla. These 

organisms are believed to have a role in cave formation, 

and the pristine conditions of Lechuguilla Cave provide 

an unprecedented opportunity to study natural cave 

processes and cave climate. Lechuguilla is within a 

designated wilderness area and has no human 

developments above it to alter cave processes. 

Over 89 miles (143 km) of passages have been discovered 

and mapped in Lechuguilla Cave, which may be 

connected to other known caves outside the park 

boundary, such as Big Manhole Cave (NPS 1996). 

Surveyed passages extend within about 600 feet (183 m) 

of the north boundary of the park. Closed to recreational 

caving, Lechuguilla is open by permit only for 

exploration and mapping, limited documentational 

photography, and research in such fields as cave 

mineralogy, microbiology, biology, and 

paleoclimatology. 

Slaughter Canyon Cave 

Formerly called New Cave or New Slaughter Cave, 

Slaughter Canyon Cave is one of the larger caves in the 

park. Located just within the mouth of Slaughter Canyon 
 CAVE Geologic Resource Evaluation Report 17

about 8.5 miles (9.5 km) southwest of the visitors center, 

Slaughter Canyon Cave is about 1.75 miles (2.6 km) long. 

The main corridor is approximately 1,170 feet (357 m) 

long with cross sections up to 220 feet (67 m) wide. The 

cave is characterized by large rooms with arched ceilings. 

Parts of the cave are highly decorated with speleothems, 

including an 89-foot (27 m) column. The hillside above 

the site contains fore-reef and related fossils. 

Ogle Cave 

Ogle Cave is connected to Rainbow Cave. The two caves 

formed independently and are connected by a tight joint 

passage called Blood Fissure. Ogle Cave is located high 

on the east side of Slaughter Canyon, across from 

Slaughter Canyon Cave. 

Ogle Cave is one large linear passage about 1,500 feet 

(488 m) long and averages about 100 feet (30 m) in height 

and width. The cave is one of the larger chambers in the 

park. Entry into the cave requires a 180-foot (59 m) 

technical descent on ropes through a naturally occurring 

vertical passage. 

The cave is decorated with large speleothems. Some of 

the larger speleothems include massive stalactites, 

stalagmites, draperies, flowstone, bell canopies, and The 

Bicentennial column (one of the world’s tallest at 106 

feet). Smaller speleothems include shields, rimstone 

dams, cave pearls, helictites, popcorn, and rafts. 

Backcountry Caves 

Ten of the 84 known backcountry caves are open to 

cavers with NPS permits. The volume and length of these 

cave passages vary. Several of the park caves may be 

interconnected and some may be connected with caves 

outside the park (NPS 1996). 

Caves Outside the Park 

The Guadalupe district of Lincoln National Forest 

contains more than 120 known caves. Most of these are 

along Guadalupe Ridge just west of Carlsbad Caverns 

NP. Cottonwood Cave is one of the most prominent with 

a massive entrance, large formations, almost 3 miles (5 

km) of passages, and gypsum deposits in the form of 

flowers and hanging chandeliers. Other caves include 

Virgin Cave, Black Cave, Hell Below Cave, Three Fingers 

Cave, and Madonna Cave. 

Several well-known caves are within the Lechuguilla 

Cave protection area just north of the park. The BLM 

Dark Canyon special management area is contiguous 

with the northern boundary of the park. Big Manhole 

Cave is about 1.25 surface miles (2 km) from the entrance 

to Lechuguilla and contains deposits of paleontological 

materials. Big Manhole Cave may be connected with 

Lechuguilla Cave. Mudgetts Cave and Snake Trap Cave 

are two other significant caves on BLM land and are 

close to the park’s northern boundary. 

Permian Reef Features 

The semiarid plateau that surrounds the park is 

composed of reef limestones deposited between 240 and 

280 million years ago during the Permian Period. The 

Guadalupe Mountains offer a remarkable record of 

environments associated with this ancient reef complex. 

The massive, unstratified limestone reef deposits of the 

Capitan Limestone form the escarpment seen to the 

southwest of the visitors center. Unlike modern reefs, 

which are composed mainly of coral, the primary 

framework of this Permian reef was made up of 

calcareous sponges, algae, and bryozoans (figure 7). 

Skeletal deposits of dead organisms were bound by 

encrusting organisms and natural calcite cement that 

filled pore spaces. Today, the preserved reef is 

approximately 750 feet (230 m) thick. The 1,000-foot 

cliff, El Capitan, in Guadalupe National Park is 

composed primarily of the massive Capitan Limestone 

and most of Carlsbad Caverns lies within this same 

formation. The ancient reef now preserved in the 

Capitan Limestone once resembled modern reefs that 

fringe the coastline of modern Belize in Central America 

today. 

Outcrops in Bat Cave Canyon and Walnut Canyon 

expose the reef fabric and four significant elements of 

the reef facies: 1) an in situ framework of oriented 

organisms; 2) encrusting and binding organisms that 

added stability to the framework; 3) internal sediment of 

skeletal fragments, pellets, or other grains lodged in open 

pores in the framework; and 4) submarine cement crusts 

filling virtually all remnant porosity. (New Mexico 

Institute of Mining and Geology, access 2005). 

The plateaus and canyons that today form the landscape 

northwest of the Guadalupe escarpment contain the 

back-reef environments of the Permian reef complex. 

Features that record the transition from reef to back-reef 

are exposed in Walnut Canyon. Immediately landward of 

the reef is the back-reef grainstone facies (figure 8). 

Strata show signs of open marine circulation, with 

normal or only slightly hypersaline conditions. Marine 

fossils are abundant, especially fusulinids and other 

foraminifers, gastropods, pelecypods, green algae 

(especially Mizzia and Macroporella), blue green algal 

boundstones, oncoids, and other skeletal grains. The 

carbonates change from massive reef limestone to 

bedded grainstones and packstones. 

Aggregates of round carbonate-coated particles, called 

pisolites, distinctive features of Grayburg, Queen, Seven 

Rivers, Yates, and Tansill rocks are found landward of 

the grainstone facies (figure 8). The back-reef pisolite 

facies is an elongate feature, parallel to the reef trend 

exposed in Walnut Canyon and in outcrops along the old 

guano trail by the cave entrance. As in the Permian, 

pisolites form today in warm, high calcium carbonate 

water landward of the reef. They range from a few 

millimeters to 5 centimeters in diameter). 

The Permian pisolitic deposits are associated with large 

(3-10 ft [1-3 m] high; 30-80 ft [10-25 m] diameter) 

polygonal features termed “teepee structures” (figure 9) 

(Dunham 1969; Kendall 1969). Teepee structures are 

polygonal expansion features marked by buckled and 

deformed sediments, crusts of precipitated (originally 
 NPS Geologic Resources Division 18 

aragonite) cement, and pockets of pisolitic sediment 

beneath and between the polygonal bulges. They are 

usually stacked in a series of inverted ‘V’s. Good 

examples of teepee structures are found near the bottom 

of the bat flight amphitheater, and are also exposed in 

Walnut Canyon. 

The pisolites may be the most controversial facies in the 

Permian of the Texas-New Mexico area (New Mexico 

Institute of Mining and Geology, access 2005). The 

origin of pisoliths and tepee structures have been the 

subject of numerous studies and considerable 

controversy. Pisolite formation is attributed to one of the 

following three hypotheses: 1) marine inorganic 

precipitation in a subtidal setting; 2) caliche formation in 

continental areas or coastal spray-zones where carbonate 

sediment is brought in by storms or other episodic 

processes; and 3) back-barrier, marine or groundwater 

seepage through permeable barriers into sub-sea level 

salinas. Adding to the quandary is the lack any modern 

analog that comes close to modeling the breadth and 

abundance of pisoliths preserved in the Permian reef 

complex (Scholle and Kinsman 1974; Esteban and Pray 

1977, 1983; New Mexico Institute of Mining and 

Geology, access 2005). 

The persistence of the pisolite facies in space and time, 

its elongate geometry parallel to the reef trend, and its 

consistent juxtaposition between open marine and 

restricted environments indicate that the pisolite facies 

formed a subaerial barrier between the inner and outer 

back-reef environments. This scenario would favor 

either the caliche or salina seep interpretations. Further 

support for the salina seepage model comes from a 

number of studies of modern coastal salinas, lakes, and 

sabkhas in southern and western Australia. Conceivably, 

an elongate, irregular ridge of low-relief islands, tidal 

flats, and dunes formed just seaward of the pisolites 

which allowed marine water seepage into the back 

barrier lagoon. Exposures in the park allow further 

testing of all three hypotheses. 

Dolomitic mudstones and thin sandstone beds formed in 

shallow, quiet, and relatively still waters of back-reef 

lagoons landward of the pisolite facies (figure 8). Dry 

periods produced mudcracks formed by the buckling of 

sediments as they partially dried. Mudcracks typically 

form polygonal structures in a honeycomb pattern. 

Mudcracks are exposed on the flat ceiling in Carlsbad 

Cavern near the Bat Cave sign. Modern back-reef 

lagoons similar to those in the Permian exist today off the 

coast of Florida. 

Back-reef deposits that formed farthest landward from 

the reef were subject to periodic drying, which 

concentrated minerals in the water creating extremely 

saline conditions. Consequently, most marine organisms 

could not survive in this harsh environment. Most of the 

fossils seen in back-reef outcrops are gastropods and 

some types of algae. 

Today, semi-permeable clay layers in the Tansill 

Formation prevent rainwater and snowmelt from easily 

percolating downward to lower layers. The groundwater 

accumulates above the clay layers and then moves 

horizontally until it emerges in springs or seeps along 

canyon walls. Big Hill Seep, which can be viewed from a 

pull-out along the Walnut Canyon drive, is one example 

of this lateral groundwater flow. 

The fore-reef environment formed on the ocean side of 

the reef. As the reef grew upward in the Permian, large 

house-sized blocks of the reef collapsed or were broken 

off by waves and fell into deeper water. This process 

created a poorly sorted debris pile at the base of the reef 

composed of lime mud, fossils, and reef fragments. 

Carlsbad Caverns is developed primarily in the fractured 

reef and fore-reef Capitan Limestone, but the entrance 

and all of the upper level are in the back-reef dolomites 

of the Tansill and Yates Formations. The deep parts of 

the cave are cut in the lower part of the reef as well as 

steeply-dipping fore-reef talus of the Capitan Formation. 

Fore-reef bedding is visible near the Bottomless Pit. 

Fossils 

Many invertebrate, Permian marine fossils from the 

Capitan reef system are abundant in Carlsbad Caverns 

NP. Exposed along Walnut Canyon are, calcareous 

sponges (e.g., Guadalupia, Amblysyphonella, Cystaulete, 

and Cystothalamia), Tubiphytes, stromatolitic blue-green 

algae, phylloid (leaf-shaped) algae, and bryozoans that 

form the dominant framework organisms of the reef. 

Encrusting Archaeolithoporella (a possible alga), 

Tubiphytes (found as both framework and encrusting 

forms), Solenopora (a probable red alga), Collenella (an 

algal form) and other, less common, organisms are also 

seen in the reef facies. Ancillary fauna that lived on the 

reef and that can be found in the park include 

foraminifers, ostracods, echinoids, brachiopods, and 

pelecypods. 

Fossil fauna in Walnut Canyon illustrate the change from 

reef to back-reef environments. These include 

cephalopods, foraminifers, pelecypods, gastropods, and 

dasycladacean green algae (particularly Mizzia and 

Macroporella). Most notably, sponges and encrusting 

bryozoans are missing. 

Modern reefs are commonly formed by large 

communities of coral, but in the Permian reefs, coral was 

rare. Solitary horn coral were present but are relatively 

uncommon in outcrop. Brachiopods were abundant and 

exhibit a wide variety of shapes. Nautiloids, swimming 

predators related to the modern chambered nautilus, 

squid and octopus, are also present. Most nautiloids 

were extinct at the end of the Permian. Crinoids attached 

themselves to the seafloor and were common inhabitants 

in well-circulated Permian reef environments although 

most species died out at the end of the Permian period. 

Two species of trilobites along with the largest fossil 

sponge yet known from the Permian of North America 

have been discovered at Carlsbad Caverns (Santucci et al. 

2001). Trilobites were among the dominant life forms in 

the Paleozoic Era but were in decline in the Permian 

Period and were extinct by the end of the period. 
 CAVE Geologic Resource Evaluation Report 19

Carlsbad Caverns, Lechuguilla Cave, Slaughter Canyon 

Cave, and Musk Ox Cave have yielded Pleistocene to 

Holocene vertebrate fossils. Thirty-six species have been 

identified from the park caves, and among these species 

are Pleistocene shrub oxen, pronghorn, an extinct 

cheetah-like cat, mountain goat, dire wolf, shrew, 

marmot, horse, and an extinct vulture. 

In the Lower Cave and the Big Room within Carlsbad 

Caverns, fossilized bats, a Pleistocene jaguar, and recent 

mountain lion bones have been discovered in a location 

that indicates the animals must have entered the cave by 

a different route than the present-day entrance (Santucci 

et al. 2001). In 1947, remains of a juvenile Shasta ground 

sloth (Nothrotheriops shastensis) were discovered in 

Lower Devil’s Den. Additional bones were found in 

1959. Dated at 111,900 years B.P., these bones provided 

the oldest absolute date for any sloth material and the 

oldest absolute date for any vertebrate remains from the 

Guadalupe Mountains. 

Ringtail cat (Bassariscus astutus) fossils are reported from 

Lechuguilla Cave along with fifteen complete or partial 

bat skulls. The bat fossils date to less than 10,000 years 

B.P. and include a hoary bat (Lasiurus cinereus) not 

commonly found in caves, a western big eared bat 

(Plecotus townsendii) that prefers shallow gypsum caves 

or entrances of caves or mines, a long-legged bat (Myotis 

volans) that prefers rock crevices or trees, and a smallfooted myotis (Myotis leibii) that was the most abundant 

inhabitant of Lechuguilla Cave. Myotis leibii has not been 

found at Carlsbad Cavern which is only three miles 

southeast of Lechuguilla Cave. 

Slaughter Canyon Cave (New Cave) is the only cave that 

has yielded the extinct Constantine’s free-tailed bat 

(Tadarida constantinei). Mountain deer (Navahoceros 

fricki) and other vertebrate fossils also have been found 

in Slaughter Canyon Cave. 

Vertebrate fossils discovered in Musk Ox Cave represent 

an assemblage of Late Pleistocene fauna that died after 

being trapped in a large sinkhole. A horse, a small 

artiodactyl, a bovid, a large dog, a bobcat-like feline, a 

shrub ox, and a small antelope have been identified 

among the remains. Further exploration of the cave in 

1975 led to the discovery of two skulls and a skeleton 

that were identified as bush ox (Euceratherium cf. 

sinclairi) and dire wolf. A follow-up trip discovered 

remains of Harrington’s Mountain Goat (Oreamnos 

harringtoni) in the cave. 

Structural Features 

Guadalupe Ridge is a large anticline that dips gently to 

the northeast. Walnut Canyon occupies a 

complementary syncline to the north. Bat Cave Draw, 

situated between the two main east-west passages of the 

cavern, is a smaller synclinal structure within the large 

Guadalupe Ridge. Associated with these structures are 

NW-SE and NE-SW stress-strain trends that influence 

the distribution and orientation of open versus closed 

fractures defining the hydrology of the cave system. 

Brooke (1996) observed two primary joint orientations: a 

major orientation of joints between N70°E and N90°E 

and a second significant orientation between due north 

and N30°W. Brooke’s results corresponded to those 

found by Tallman (1993) in a regional study of the area, 

also. Local joints have the same orientation as the major 

caves. Both joint and cave orientations follow regional 

structural trends. The dominant joint and cave 

orientation is parallel to the ridge axis. The second major 

orientation is perpendicular to the ridge axis (Van der 

Heijde et al. 1997). 

Uplift and folding of the Guadalupe block in Cenozoic 

time resulted in the preferential joint orientation present 

today at the park. The continuity, frequency, and 

hydraulic effectiveness of the joints are controlled and 

dependent upon the competence of the rock layers and 

the magnitude of the stresses and strains to which these 

layers have been subjected. Joints within the massive 

Capitan Limestone are relatively continuous with some 

reaching 100 feet (33 m) or more. Fractures in the 

dolomite and limestone layers of the Tansill Formation, 

however, are less continuous due to the presence of local 

siltstone layers. 
 NPS Geologic Resources Division 20 

Figure 5. Schematic diagram illustrating the evolution of the cave system at Carlsbad Caverns National Park. A) Small, random solutional 

openings form in the zone of saturation. B) The water table lowers as the Guadalupe block is uplifted, producing sulfuric acid that dissolves 

limestone. Caves begin to form. C) Downcutting and cave formation continues as the water table is lowered with continued uplift. Modified 

from Kiver and Harris (1999). 
 CAVE Geologic Resource Evaluation Report 21

Figure 6. Speleothems in The Big Room: The Hall of Giants (top) and the Chandelier (bottom). Photos used with the permission of FinleyHoliday Film Corp. 
 NPS Geologic Resources Division 22 

Figure 7. More speleothems in the Big Room, Temple of the Sun. Photo used with the permission of Finley-Holiday Film Corp. 
 CAVE Geologic Resource Evaluation Report 23

Figure 8. A portion of the diorama of the Capitan reef produced by Terry L.Chase and displayed at the Permian Basin Petroleum Museum in 

Midland, Texas. This artist's conception emphasizes the framework sponges and the abundant encrusting fauna. Photograph by Peter 

Scholle, New Mexico Institute of Mining and Geology 1999. 
 NPS Geologic Resources Division 24 

Figure 9. Shelf-to-basin spectrum of depositional environments for Capitan and Capitan-equivalent strata of the Guadalupe Mountains. 

Vertical axis is approximately 0.5 km; horizontal axis is roughly 35 km. Diagram from the New Mexico Institute of Mining and Geology, 

http://www.geoinfo.nmt.edu/staff/scholle/graphics/permdiagr/GuadPaleogeog.html (access 2005). 

Figure 10. Tepee structure in Tansill Formation. Light yellow layers are dolomitized pisolitic and fenestral sediment; darker, gray layers are 

zones of sheet spar (aragonitic cement crusts). Outcrop at southwest end of parking lot at Carlsbad Caverns visitor's center. Photograph by 

Peter Scholle, New Mexico Institute of Mining and Geology 1999. 
 CAVE Geologic Resource Evaluation Report 25

Map Unit Properties 

This section provides a description for and identifies many characteristics of the map 

units that appear on the digital geologic map of Carlsbad Caverns National Park. The 

table is highly generalized and is provided for informational purposes only. Ground 

disturbing activities should not be permitted or denied on the basis of information 

contained in this table. More detailed unit descriptions can be found in the help files that 

accompany the digital geologic map or by contacting the NPS Geologic Resources 

Division. 

The sedimentary rocks exposed at Carlsbad Caverns 

National Park are primarily limestone and dolomite that 

formed in back-reef and reef settings. The following Map 

Unit Properties Table presents a view of the stratigraphic 

column and an itemized list of features for each rock 

unit. Some of the units in the table are correlative so that 

the geologic column does not represent consistent 

younger-to-older strata within the Permian Epochs. For 

example, the Tansill Formation, Capitan Limestone, and 

Bell Canyon Formation, although geographically distinct, 

are correlative as are the Yates, Capitan Limestone, and 

Bell Canyon Formations (figure 3). 

Specific properties of the different formations are 

included in the table that may be significant with regard 

to management decisions. The properties in the table 

include the formation name, a lithologic description of 

the unit, its resistance to erosion, suitability for 

development, hazards, paleontologic resources, cultural 

and mineral resources, karst issues, and a miscellaneous 

category. The units in the table are the same that are on 

the accompanying digitized geologic map. 
Map Unit Properties Table 

Period Map Unit (symbol) Unit Description Erosion Resistance Paleontology Resources Cultural Resources Karst Issues 

Alluvium 

(Qal) 

Gypsiferous and calcareous sand & silt. Mapped only in Black River Valley & Dark Canyon. Low None None documented None 

QUATERNARY Gravel (Qg) Poorly sorted uncemented limestone pebbles and cobbles from Capitan Limestone and Carlsbad Group; associated silt & clay; some cemented by caliche or travertine; covers much of Castile Fm, esp. north and west of Black River; 200+ ft (61+ m) thick south of Rattlesnake Canyon and 

west of Black River; 300+ ft (91+ m) thick in wells north of Carlsbad Caverns NP 

Low None None documented None 

TERTIARY Dikes (Ti) Three fine- grained, vesicular, alkali trachyte dikes cut the Castile Fm in secs. 11, 14, & 15, T26S., R24E (south of Capitan Ls escarpment; west of Hwy 62); strike about 60 degrees NE; dip about 80 degrees N; 1,000 to 4,000 ft (305 to 1,200 m) long; Appear as weathered linear zones of brownish soil None None None 

Rustler 

Formation 

(Pr) 

Grayish- pink cryptocrystalline porous dolomite exposed in scattered outcrops south of Capitan Limestone escarpment 

Scattered outcrops south of Carlsbad Caverns NP 

Dolomite contains mollusks, brachs, normal- marine fossils. Anhydritic parts contain molluscan fauna only 

Not in Carlsbad 

Caverns NP N/A 

Castile 

Formation 

(Pcs) 

White massive gypsum in the East Quad with some interlaminated white gypsum & dark- gray limestone in the lower part; may include residual gypsum & clastics of the Salado and Rustler Formations in the upper 150 ft; thinly laminated light- to dark- gray granular limestone near the southwest corner and alternating very thin laminae of dark- gray limestone & gypsum in southeast corner of the West Quad; massive white gypsum near mouth of Rattlesnake Canyon 

Exposed south of Capitan Limestone escarpment 

Non- fossiliferous 

Aquitard to groundwater flow 

Tansill 

Formation 

(Carlsbad 

Gp) 

(Pt) 

Light olive gray to very pale orange fine- grained laminated occasionally pisolitic dolomite, mostly in beds 0.5 to 5 ft (0.2 to 1.5 m) thick, & rare thin beds of very pale orange very fine grained quartz sandstone or siltstone; at least 300 ft (90 m) thick near mouth of Slaughter Canyon, normally between 100 and 150 ft (30 to 46 m) thick 

High; caps summit of Guadalupe Mtns and over Capitan reef 

Gastropods, fusulinids, crinoids, algae near reef 

Few karst features 

Yates 

Formation 

(Carlsbad 

Gp) 

(Pya) 

Very pale orange to yellowish- gray fine- grained laminated frequently pisolitic dolomite, mostly in beds 0.3 to 2 ft (0.1 to 0.6 m) thick, alternating with grayish- orange to pale yellowish orange calcareous quartz siltstone or 

very fine grained sandstone, mostly in beds 1 to 6 in (2.54 to 15 cm) thick; 270 ft (82 m) thick in North Slaughter Canyon to 375 ft (125 m) thick closer to Capitan Limestone 

Slope- forming siltstone & sandstone beds alternating with dolomite ledges 

Fusulinids, pelecypods, gastropods, scaphlopods near reef 

Low permeable siltstone inhibits groundwater infiltration; some karst 

PERMIAN 

Seven Rivers 

Formation 

(Carlsbad 

Groupp) 

(Ps) 

Carbonate facies (Psc): yellowish- gray fine- grained 

laminated frequently pisolitic dolomite mostly in beds 1 to 3 feet (0.3 to 0.9 m) thick with rare thin beds of very pale orange quartz siltstone. Evaporite facies (Pse): white gypsum with associated light 

olive gray to pale- red aphanitic dolomite & pale reddish brown siltstone; formation thickness: 335- 600 ft (110- 200 m) 

High; Resistant dolomite (overlies Queen Fm) 

Fusulinids, pelecypods, gastropods, scaphlopods near reef; fossils rare in evaporite facies 

 Some karst 
Period Map Unit (symbol) Unit Description Erosion Resistance Paleontology Resources Cultural Resources Karst Issues 

Capitan 

Limestone 

(Pc) 

Massive (reef) Member (Pcm): very light gray to light 

olive gray, may contain irregularly branching dikes of grayish- orange calcareous quartz siltstone; thickness: 750 to 1000 ft (250- 335 m). Breccia (reef- talus) Member (Pcb): foreslope facies; very 

light gray to light olive gray fine- grained locally brecciated limestone with widely spaced indistinct bedding planes inclined 20 to 30 degrees to the southeast; thickness: 750 to 1000 ft (250- 335 m) 

High; cliff former 

Reef framework species: calcareous sponges (Guadalupia, Amblysyphonell, Cystaulete, Cystothalamia), Tubiphytes, 

algae (blue- green, phylloid, red Solenopora), bryozoans; Others: fusulinids, coral, crinoids, brachiopods, cephalopods, pelecypods, echinoderms, ammonoids, mollusks, trilobites; Pleistocene/Holocene vertebrate remains in caves: shrub oxen, pronghorn, mountain goat, dire wolf, shrew, marmot, horse, vulture, cheetah- like cat, ground sloth, free- tailed bat, deer,artiodactyls, bovid, dog 

Cultural 

resources in 

caves; home to 

bats 

Cavernous, massive, high fracture permeability; speleothems; massive limestone inhibits groundwater flow 

Bell Canyon 

Formation 

(Pbc) 

Dark- gray fine- grained fetid limestone in beds 1 to 12 in (2.54 to 30 cm) thick & brown- weathering very thin bedded quartz siltstone 3 to 5 feet (0.9 to 1.5 m) thick at top; limestone locally contains abundant silicified fossils; becomes sandstone- rich towards the basin 

Not exposed in park; exposed SW of Carlsbad & in GUMO 

Bryozoans fusulinids, corals, brachiopods, echinoderms, conodonts, radiolaria, sponges, ammonoids 

Not exposed in 

park 

Forereef deposits – no caves in map area 

Queen 

Formation 

(Pq) 

Very pale orange to yellowish- gray fine- grained laminated dolomite mostly in beds 0.3 to 4 ft (0.1 to 1.2 m) thick interbedded with very pale orange silty dolomite, calcareous quartz siltstone, & very fine- grained sandstone in beds 0.3 to 3 ft thick (0.1 to 0.9 m); sandstone is largely confined to the basal part and siltstone is predominant in the upper 100 ft (30 m) (Shattuck Member); ripple marks, cross- bedding, channel cuts in many beds; thickness at type locality is 421 ft (128 m) 

Shattuck Member siltstone is relatively nonresistant 

Crinoids, echinoids, bryozoans, pelecypods, gastropods, scapholopods, algae near reef; fossils rare in evaporite facies 

None 

documented 

None 

documented 

Goat Seep 

Dolomite 

(Pgs) 

Thickly- bedded to massive, finely- crystalline to saccharoidal, cream to light- gray dolomite; shelf margin reef dolomite underling younger Capitan Ls; exposed in extreme SW corner of map area and perhaps Lechuguilla Cave; exposures along Western Escarpment of Guadalupe Mtns from Last Chance Canyon southward; up to 1,300 ft 

(400 m) thick 

High; exposed west of Carlsbad Caverns NP 

Sponges, brachiopods, pelecypods, bryozoans, coral, crinoids, echinoderms; (rare) gastropods & ammonoids 

None 

documented 

If exposed in Lechuguilla Cave, it is one of only a few caves developed in Pgs 

PERMIAN 

Grayburg 

Formation 

(Pg) 

Yellowish- gray to very pale orange laminated finegrained generally oolitic dolomite mostly in beds 3 to 18 in (7.6 to 46 cm) thick interbedded with yellowish- gray cross- laminated fine- grained oolitic limestone in beds 6 to 18 in (15 to 46 cm) thick, with very pale orange crosslaminated calcareous or dolomitic quartz siltstone or very fine- grained sandstone in beds 4 to 30 in (10 to 76 cm) thick; overlies San Andres Ls along a karstic unconformity; underlies Queen Fm.; basal white sandstone beds form a conspicuous ledge in Last Chance Canyon; about 435 ft (133 m) thick 

High; dolomites and sandstones form cliffs 

Fusulinid molds (Parafusulina dunbari), 

gastropods, crinoids, brachiopods, pelecypods, nautiloids, algae near reef; fossils rare in evaporite facies 

None 

documented 

None 

documented in 

Carlsbad 

Caverns NP 
Period Map Unit (symbol) Unit Description Erosion Resistance Paleontology Resources Cultural Resources Karst Issues 

Cherry 

Canyon Fm. 

– sandstone 

tongue 

(Pcc) 

Grayish- orange to pale yellowish orange cross- bedded dolomitic or calcareous very fine- grained quartz sandstone containing abundant silicified fossils; largescale cross- bedding and channel fillings exposed in Last Chance Canyon; underlies thin San Andres Fm in northwestern part of park; 260 ft (80 m) thick at mouth of Sitting Bull Canyon 

Moderately resistant in map area; generally forms slopes 

Lower part: fusulinids, echinoid spines, sponges, brachiopods 

None 

documented 

None in 

Carlsbad 

Caverns NP 

San Andres 

Limestone 

(Psa) 

Very pale orange fine- grained generally cherty fetid dolomite and limestone in even to irregular beds a few inches to several ft thick; mapped in Last Chance and Sitting Bull Canyons Upper Member (Psau): non- cherty, dark, slabby 

limestone; 100 ft (30 m) thick in Last Chance Canyon, NW corner of map area Lower cherty Member (Psal): cherty limestone; 200 ft (60 

m) thick in Last Chance Canyon, NW corner of map area 

Resistant to 

erosion 

Common fossils: gastropods, brachiopods, fusulinids, sponges, corals, bryozoans, chitons, scaphopods, pelecypods, nautiloids, ammonoids, trilobites, shark’s tooth 

None documented 

Limited exposures in park – no karst issues 

PERMIAN 

Yeso 

Formation 

(Py) 

Dolomite, some limestone, red, yellow, & gray siltstone, yellowish fine- grained sandstone, & gray- to- white bedded and nodular gypsum; basal unit thin- bedded, nodular, cherty ls interbedded with gypsum; limited exposures in NW part of map 

Low 

Rare fossils in evaporite sections; poorly preserved brachiopods, bryozoans, crinoids, gastropods, fusulinids in nonevaporite sections 

Thin limestone beds: no karst issues 

Unit descriptions are from Hayes (1974), Hayes and Koogle (1958), and Hill (1996). 
 CAVE Geologic Resource Evaluation Report 29

Geologic History 

This section highlights the map units (i.e., rocks and unconsolidated deposits) that occur 

in Carlsbad Caverns National Park and puts them in a geologic context in terms of the 

environment in which they were deposited and the timing of geologic events that created 

the present landscape. 

During the Permian Period (286-245 Ma) (figure 10), the 

Carlsbad Caverns region was near the equator. Western 

North America was submerged beneath a shallow 

tropical ocean while a broad alluvial plain spread across 

eastern North America. The Appalachian Mountains 

formed as plate tectonic activity closed the protoAtlantic Ocean and lithospheric plates collided. As the 

supercontinent, Pangaea, formed in the late Permian and 

early Triassic, the proto-Gulf of Mexico also closed as 

South America collided with what would become the 

North American continent (figure 11). This collision was 

responsible for uplift of the Ancestral Rocky Mountains 

in Colorado. 

Active plate convergence caused a rise in sea level, which, 

combined with regional subsidence, led to the 

encroachment of a shallow Permian sea into the 

southwestern region of the North American continent. 

An arid climate prevailed in the western part of Pangaea 

restricting marine evaporitic conditions over much of the 

continental shelf seaway (Peterson 1980). 

An arm of this Permian sea flooded into New Mexico 

and west Texas occupying the Delaware Basin, which 

had a connection to the open ocean through the Hovey 

Channel, a narrow channel to the south (figure 2) (King 

1948; Hill 1996; New Mexico Institute of Mining and 

Geology 2005). The Delaware Basin was a relatively deep 

cratonic basin with depths on the order of 2,000 feet (600 

m). The Hovey Channel restricted water flow into the 

basin much like the Strait of Gibraltar restricts the 

connection of the Mediterranean Sea with the Atlantic 

Ocean. Consequently, circulation in the basin was poor 

and an anoxic environment at depth allowed for the 

thick accumulation of organic material that later, with 

burial and maturation, transformed into hydrocarbons. 

In the warm, shallow, tropical sea, organic reefs thrived 

and ringed the Delaware Basin. Depositional 

environments landward of the reef included redbeds, 

sabkha evaporites, lagoonal mudstones, pisolitic 

grainstones, and back-reef grainstones while fore-reef 

and basin deposits were seaward of the reef (figure 8). 

Redbeds, composed of clastic terrigenous detritus, were 

closest to shore and derived their fine-grained sediments 

from the north, northeast, and perhaps also the 

northwest. Sabkha environments formed on the seaward 

margin of the redbeds and consisted of nodular and 

mosaic gypsum (sometimes halite) interbedded with 

some dolomite and red siltstone. This association also is 

found on modern coastal sabkhas. 

Seaward of the main evaporite deposits are fine-grained, 

thin-bedded dolomicrites deposited in a shallow subtidal 

or lacustrine setting or a hypersaline marine lagoon (Sarg 

1981; Hill 1996; New Mexico Institute of Mining and 

Geology 2005). Fossils are rare in the tidal flat. 

Interbedded lagoonal sandstones may represent both 

fluvial and eolian processes, but probably most are 

subaqueous deposits. Back-reef lagoons probably were 

less than 100 feet (30 m) deep and may have been 

emergent at times, but likely they were never deeper than 

3oo feet (100 m) (Hill 1996). Low porosity is 

characteristic of these strata since pore spaces were 

plugged with evaporite minerals, especially anhydrite 

(CaSO4). 

Thin (20 cm to 2 m; 8 in to 7 ft) beds of sandstone are 

interbedded with the dolomicrites. These clastic beds 

have few sedimentary structures and essentially no fossils 

or trace fossils. They may represent small progradational 

advances of sabkha-type sedimentation across the backreef lagoonal area. 

Seaward of the lagoonal mudstones lies the pisolitic 

grainstone facies. This facies is about 1 mi (1.6 km) wide 

and about 1 mi (1.6 km) thick (it persists throughout the 

Grayburg to Tansill section). Irregularly bedded deposits 

of laminated, fenestral carbonate and beds of skeletal 

debris are interbedded with abundant lenticular zones of 

pisolitic dolomite. The pisoids range in size from 0.04 

inches to 2 inches (a few millimeters to greater than 5 

cm), and although very porous on outcrop, this facies 

shows extensive filling by evaporite minerals in the 

subsurface. Associated with the pisolites are teepee 

structures. 

The pisolite facies is always found as a transitional zone 

between fossiliferous marine grainstones, packstones, 

and wackestones on the seaward side and the largely 

barren, evaporitic dolomicrites on the landward side 

(figure 8) (Scholle and Kinsman 1974; Esteban and Pray 

1977, 1983). The consistent geometry and restricted 

environments of the pisolite facies indicate that at least 

part of this facies formed a narrow strip of land that was 

subaerially exposed (except for tidal channels). As such, 

this facies represents a long-lived barrier to water 

movement between open shelf and lagoonal settings. 

The back-reef grainstone facies lies seaward of the 

pisolite facies (figure 8). Strata show signs of open marine 

circulation, with normal or only slightly hypersaline 

conditions. Marine fossils are abundant, especially 

fusulinids and other foraminifers, gastropods, 

pelecypods, green algae (especially Mizzia and 
 NPS Geologic Resources Division 30 

Macroporella), blue green algal boundstones, oncoids, 

and other skeletal grains. The lithology is mostly 

grainstones and packstones. 

The back-reef grainstone facies was a topographically 

elevated area. Small, coalescing sand waves and islands, 

perhaps with intervening tidal passes, formed on the 

seaward edge of this facies and acted as an overall 

deterrent to water movement farther landward. Unlike 

the other back-reef facies, the grainstone-island belt 

underwent only partial dolomite replacement and 

relatively minor evaporite pore-filling cementation. As a 

result of their porosity and their proximity to updip, 

overlying evaporites that plug the pores and prevent the 

upward movement of liquids, rocks of this facies are 

often prolific hydrocarbon reservoirs. 

Seaward of the back-reef grainstone facies was the main 

carbonate-producing facies of the area, the reef (figure 

8). The Capitan reef was the zone of maximum faunal 

diversity. Calcareous sponges and phylloid algae formed 

the major framework organisms of the reef (figure 7). 

They were encrusted by possible red or blue-green algae. 

The reef also contained a wide variety of ancillary 

organisms such as echinoderms (both crinoids and 

echinoids), bryozoans, brachiopods, mollusks, ostracods, 

scarce solitary corals, trilobites, and others. 

Massive amounts of contemporaneous marine 

cementation played a major factor in the formation of 

the Guadalupian reefs. Large and small cavities alike 

were rapidly filled with carbonate cement precipitated 

directly from ambient seawater. This cementation 

reduced porosity to such a degree that the reef facies is 

not a significant hydrocarbon reservoir despite the fact 

that locally extensive fracturing has created zones of high 

permeability. 

Unlike today’s modern reefs (like the Great Barrier Reef 

off the Australian coast), the Permian reef probably did 

not extend into the surf zone. Careful reconstruction of 

the reef complex suggests that the Capitan Reef, the 

youngest Permian reef, probably lay a few meters to 

perhaps several tens of meters below sea level with a 

more gradual slope into the basin than the sharp reef 

break of today’s reefs (figure 8) (Garber et al. 1989; Hill 

1996; New Mexico Institute of Mining and Geology, 

access 2005). 

The rapid rate of marine cementation of the reef facies, 

coupled with the very high rate of biological 

productivity, produced more material in the reef margin 

zone than could be accommodated, given limited rates of 

subsidence. This excess material was transported into 

back-reef and fore-reef environments. The Capitan reef 

of the Guadalupe Mountains prograded seaward 

between 3 to 6 miles (5 to 10 km) despite sitting at the 

margin of a nearly 1,800-foot (600 m) deep basin. Such 

progradation required a very large volume and a high 

rate of sediment production. 

The intense contemporaneous cementation of the 

Capitan reef, coupled with rapid progradation of largely 

unconsolidated and compactable debris, led to extensive 

fracturing of the cemented reef slab during the 

depositional process. The fractures formed parallel to 

the shelf edge and filled with internal sediment, 

encrusting organisms, carbonate cement, and sand 

grains. 

The fore-reef talus apron is one of the most 

volumetrically important carbonate facies in the Permian 

reef complex. Material from the reef, near-back-reef, and 

upper slope was transported by rock fall, grain flow, 

debris flow, and turbidity currents and deposited in a 

relatively uniform apron of steeply dipping rubble. This 

poorly sorted or unsorted reef detritus varies in size from 

small fragments and individual constituent grains to 

larger blocks of lithified reef framework. Bedding angles 

exceed 35 degrees on the upper slope and gradually 

flatten to only a few degrees near the basin floor. 

Isolated sand-filled channels up to 30 feet (10 m) thick 

can be found in some areas of the upper and middle 

slope. Carbonate debris beds interfinger with sandstone 

beds. The carbonate beds thin into the basin while the 

sandstone beds, derived from the continent, thicken 

basinward. 

Basinal carbonates are very fine-grained and are 

generally finely laminated and dark-colored, although 

organic carbon content rarely exceeds one percent. Basin 

strata are mostly devoid of fauna except for a few 

radiolarians. Carbonates are not major constituents of 

the basin facies but rather, terrigenous sandstones and 

siltstones provide greater than 90 percent of the basin fill. 

They have very high porosities in the subsurface and 

make excellent hydrocarbon reservoirs. 

The basin clastics are very fine-grained, subarkosic 

sandstones and coarse siltstones that are compositionally 

very similar to the thin clastic units found on the shelf. 

The presence of abundant detrital sandstone and 

siltstone in a basin rimmed by a carbonate-producing 

system posed a significant problem in Permian basin 

stratigraphy. How were sands deposited in a basin yet 

leaving so little record in the surrounding shelf-margin 

facies? The answer was found in stratigraphic features 

that recorded episodic rise and fall of sea level. Sea level 

can change due a variety of causes such as regional 

subsidence, local tectonic effects, eustatic (global) sea 

level stands, and continent-wide vertical movements. 

In the Permian Basin, reefs and/or grainstone shoals 

flourished during high sea level stands. The platform 

margins acted as carbonate “factories” and broad 

carbonate-evaporite lagoons occupied much of the shelf 

area (figure 12). Thin, but widespread, carbonate 

turbidite units were deposited in the basins. Clastic 

sediments were either trapped in vegetated dunes or 

interdune flats, on sabkhas, or in shoreline deposits well 

up on the shelf. 

When sea level lowered, fluvial and eolian sands and silts 

spread across the shelf area, accumulating on the margins 

and eventually transported into the basins to form thick 

sandstone sequences (figure 12). Some of these sands 

and silts may also have moved through channels or tidal 
 CAVE Geologic Resource Evaluation Report 31

passes in the barrier reef during times of carbonate 

sedimentation. This would account for some lenticular 

sandstone beds, but the cyclic distribution of both shelf 

and basin carbonate-clastic packages indicates that some 

form of sedimentation with sea level change is required 

to explain the overall sediment distribution (Sarg 1985, 

1986; New Mexico Institute of Mining and Geology, 

access 2005). 

In very late Permian time, as the final suturing of Pangaea 

took place, the connection to the open ocean became 

restricted. Evaporation exceeded the inflow of normal 

marine water so that salinity increased. With increased 

salinity, life on the reef ceased. Eventually, thick deposits 

of gypsum that make up the Castile Formation filled the 

Delaware Basin and covered the reef core. 

Water depths continued to decrease and conditions 

became even more hypersaline as anhydrite, halite 

(NaCl), sylvite (KCl), and other evaporitic minerals of 

the Salado Formation were deposited. Commercial 

deposits of potash minerals have been exploited in these 

thick, last-stage fillings of the Delaware Basin. 

For most of the Mesozoic Era (figure 10), the Permian 

Basin region was part of a stable, largely nondepositional province. During the late Cretaceous to 

mid-Tertiary Laramide Orogeny, the Guadalupe 

Mountains were locally uplifted accompanied by faulting 

and southeastward tilting. Karst development may have 

begun at higher elevations. Sediment eroded from the 

higher regions may have filled any remaining karst 

features of Permian age at lower elevations. Tectonic 

activity may have mobilized hydrogen sulfide gas and 

sulfide-rich brines in mid-Tertiary time, producing 

sulfuric acid by mixing with oxygenated water infiltrating 

from the surface. Carlsbad Cavern began to form within 

the phreatic (saturated) zone although the extent of its 

development at this time is not yet known. 

During the late Cenozoic (1-3 Ma), the region was 

uplifted and the Guadalupe Mountains tilted to the eastnortheast. The caves were further enlarged, and 

extensive gypsum was deposited as a result of carbonate 

dissolution by sulfuric acid. Joints (fractures without 

significant displacement) reopened parallel to the reef 

front and a lesser set of joints formed perpendicular to 

this first set. 

Uplift and erosion continued to dissect the region during 

the Pleistocene Epoch, and the major Guadalupe caves 

gradually emerged into the vadose (unsaturated) zone. 

Erosion removed the younger rocks and part of the 

Castile Formation and exhumed the buried reef front 

that forms the Guadalupe Escarpment today. Meteoric, 

carbon dioxide-rich water from the surface deposited 

travertine speleothems, particularly during times of 

humid climate in the Pleistocene. Age dates from the Big 

Room indicate that Carlsbad Cavern was drained at that 

level more than 500,000 to 600,000 years ago. 

Eventually, erosion exposed the upper cave level and 

formed the entrance of Carlsbad Cavern. With drying of 

the cave and a decrease in infiltrating water in the 

semiarid climate, the rate of speleothem growth 

decreased. Today, Quaternary-age gravel and alluvial 

deposits continue to be deposited in the canyons along 

Guadalupe Ridge 
 NPS Geologic Resources Division 32 

Figure 11. Geologic time scale showing the various life forms and major tectonic events in North America. Ages are based on the 2004 

geologic time scale from the International Commission on Stratigraphy. 
 CAVE Geologic Resource Evaluation Report 33

Figure 12. Continental reconstruction during Late Permian (Kazanian) time. In this model, the Permian Basin lies just south of the equator 

and close to the western margin of the supercontinent Pangaea. Approximate present-day continental outlines shown for reference. From 

the New Mexico Institute of Mining and Geology, http://www.geoinfo.nmt.edu/staff/scholle/graphics/permdiagr/GuadPaleogeog.html (access 

2005) and Scotese and others (1979). 
 NPS Geologic Resources Division 34 

Figure 13. Hypothetical views of the Delaware Basin and surrounding platform areas during sea-level low- and highstands. Lowstand 

intervals were periods of terrigenous sand transport across shelves, mainly by eolian processes, and sand deposition occurred mainly in 

the basin. Highstand intervals saw development of shelf-margin reefs with associated back-reef carbonate-evaporite-redbed deposits and 

thick carbonate fore reef talus deposits. Basins of this time had only thin calcareous shale deposition. From the New Mexico Institute of 

Mining and Geology, http://www.geoinfo.nmt.edu/staff/scholle/graphics/permdiagr/GuadPaleogeog.html (access 2005). 
 CAVE Geologic Resource Evaluation Report 35

Glossary 

This glossary contains brief definitions of technical geologic terms used in this report. Not all 

geologic terms used are referenced. For more detailed definitions or to find terms not listed 

here please visit http://wrgis.wr.usgs.gov/docs/parks/misc/glossarya.html. 

allochthonous. Formed far from its present place. 

alluvial fan. A fan-shaped deposit of sediment that 

accumulates where a high gradient stream flows out of 

a mountain front into an area of lesser gradient.

back-reef. The landward side of a reef; the area and 

deposits between the reef and the mainland. 

basin (structural). A doubly-plunging syncline in which 

rocks dip inward from all sides. 

basin (sedimentary). Any depression, from continental 

to local scales, into which sediments are deposited. 

block (fault). A crustal unit bounded by faults, either 

completely or in part. 

boundstone. A sedimentary carbonate rock whose 

original components (e.g., skeletal matter, algae, 

foraminifera, etc.) were bound together during 

deposition. 

breccia. A coarse-grained, generally unsorted, 

sedimentary rock made up of cemented angular clasts. 

calcareous. A rock or sediment containing calcium 

carbonate. 

carbonaceous. A rock or sediment with considerable 

carbon, esp. organics, hydrocarbons, or coal. 

chemical weathering. The dissolution or chemical 

breakdown of minerals at Earth’s surface via reaction 

with water, air, or dissolved substances. 

clastic. Rock or sediment made of fragments or preexisting rocks. 

craton. The relatively old and geologically stable interior 

of a continent. 

cross-bedding. Uniform to highly-varied sets of inclined 

sedimentary beds deposited by wind or water that 

indicate distinctive flow conditions. 

dip. The angle between a structural surface and a 

horizontal reference plane measured normal to their 

line of intersection. 

dolomicrite. A sedimentary rock consisting of clay sized 

dolomite crystals 

dune. A low mound or ridge of sediment, usually sand, 

deposited by wind. 

eolian. Formed, eroded, or deposited by or related to the 

action of the wind. 

evaporite. Chemically precipitated mineral(s) formed by 

the evaporation of solute-rich. 

facies (sedimentary). The depositional or environmental 

conditions reflected in the sedimentary structures, 

mineralogy, fossils, etc. of a sedimentary rock. 

fault. A subplanar break in rock along which relative 

movement occurs between the two sides. 

fore-reef. The seaward side of a reef. 

grainstone. A mud-free (<1%), grain-supported, 

carbonate sedimentary rock. 

karst topography. Topography formed by the 

dissolution of calcareous rocks. 

monocline. A one-limbed flexure in strata, which are 

usually flat-lying except in the flexure itself. 

mud cracks. Cracks formed in clay, silt, or mud by 

shrinkage during subaerial dehydration. 

oncolite. A small concentrically laminated calcareous 

sedimentary structure formed by the accretion of 

successive layered masses of gelatinous sheaths of blue 

green algae, generally less than 10 cm in diameter. 

orogeny. A mountain-building event, particularly a wellrecognized event in the geological past (e.g. the 

Laramide orogeny). 

packstone. Sedimentary carbonate rock whose granular 

material is arranged in a self-supporting frame work, 

yet also contains some matrix of calcareous mud 

Pangaea. A theoretical, single supercontinent that 

existed during the Permian and Triassic Periods (also 

see Laurasia and Gondwana). 

pisolite. A round or ellipsoidal accretionary body 

commonly formed of calcium carbonate. 

permeability. A measure of the ease or rate that fluids 

move through rocks or sediments. 

porosity. The proportion of void space (cracks, 

interstices) in a volume of a rock or sediment. 

prodelta. portion of a delta below the level of wave 

erosion. 

progradation. The seaward building of land area due to 

sedimentary deposition. 

red beds. Sedimentary strata that are predominantly red 

due to the presence of ferric oxide (hematite) coating 

individual grains. 

sabkha. A coastal environment in an arid climate where 

evaporation rates are high. 

salina. A place where crystalline salt deposits are formed 

or found, such as a salt flat or pan. 

subarkose. A sandstone that does not contain enough 

feldspar to be classed as an arkose 

tectonic. Relating to large-scale movement and 

deformation of Earth’s crust. 

terrigenous. Derived from the land or continent. 

trace fossils. Sedimentary structures, such as tracks, 

burrows, etc., that preserve evidence of organisms’ life 

activities, rather than the organisms themselves. 

travertine. A limestone deposit or crust formed from 

precipitation of calcium carbonate from saturated 

waters, especially near hot springs and in caves. 

uplift. A structurally high area in the crust, produced by 

movement that raises the rocks. 

wackestones. Sedimentary carbonate rock whose 

granular material is arranged in a self-supporting frame 

work, yet also contains some matrix of calcareous 

mud. 
 NPS Geologic Resources Division 36 

References 

This section provides a listing of references cited in this report. A more complete geologic 

bibliography is available and can be obtained through the NPS Geologic Resources 

Division. 

Berg, R.R. 1979. Reservoir sandstones of the Delaware 

Mountain Group, southeast New Mexico, in N.M. 

Sullivan, ed., Guadalupian Delaware Mountain Group 

of West Texas and Southeast New Mexico: Permian 

Basin Section – SEPM, Publication 79-18, p. 75-95. 

Bowen, E.M. 1998. Hydrogeology of Rattlesnake Springs: 

Eddy County, New Mexico: New Mexico Institute of 

Mining and Technology, M.S. Thesis, 170 p. 

Bremer, M. 1998. Preliminary assessment of 

environmentally-sound methods for treating and or 

diverting rainwater run-off from parking lots and 

roads in the vicinity of Carlsbad Cavern: Carlsbad, 

New Mexico, National Park Service draft report 62 p. 

Brooke, M. 1996. Infiltration pathways at Carlsbad 

Caverns National Park determined by Hydrogeologic 

and hydrochemical characterization and analysis: 

Colorado School of Mines, M.S. Thesis, 182 p. 

Bureau of Land Management. 1993. Final Dark Canyon 

Environmental Impact Statement: Prepared by the 

New Mexico State Office and Roswell District Office. 

Burger, P.A., and D.L. Pate 2001. Using Science to 

Change Management Perspectives at Carlsbad Caverns 

National Park, in E.L. Kuniansky, ed, U.S.G.S. Karst 

Interest Group Proceedings, Water-Resources 

Investigations Report 01-4011, p. 47-51. 

Cahill, T., and M. Nichols 1991. Charting the splendors 

of Lechuguilla Cave: National Geographic, v. 179, no. 

3, p. 34-59. 

Cunningham, K.I., H.R. DuChene, and C.S. Spirakis. 

1993. Elemental sulfur in caves of the Guadalupe 

Mountains, New Mexico, in D.W. Love, ed., Carlsbad 

Region, New Mexico and West Texas: New Mexico 

Geological Society, Guidebook, 44th Annual Field 

Conference, p. 129-136. 

Cunningham, K.I., H.R. DuChene, C.S. Spirakis, and J.S. 

McLean. 1994. elemental sulfur in caves of Guadalupe 

Mountains, New Mexico (abs.), in I.D. Sasowsky and 

M.V. Palmer, Breakthroughs in Karst 

Geomicrobiology and Redox Chemistry: Karst Waters 

Instit. Spec. Publ. I, Abs. And Field Trip guide, 

Colorado Springs, p. 11-12. 

Davis, D.G., A.N. Palmer, and M.V. Palmer. 1992. 

Extraordinary subaqueous speleothems in Lechuguilla 

Cave, New Mexico: National Speleological Society 

Bulletin, v. 52, p. 70-86. 

Dolton, G.L., A.B. Coury, S.E. Frezon, K. Robinson, K.L. 

Varnes, J.M. Wunder, and R.W. Allen. 1979. Estimates 

of undiscovered oil and gas, Permian Basin, west Texas 

and southeast New Mexico: U.S.G.S. Open-file Report 

79-838, 118 p. 

DuChene, H.R. and K.I. Cunningham. 2006. Tectonic 

Influences on Speleogenesis in the Guadalupe 

Mountains, New Mexico and Texas: New Mexico 

Geological Society Guidebook, 57th Field Conference, 

Caves and Karst of Southeastern New Mexico, 

p. 211-218. 

Dunham, R.J. 1969. Vadose pisolite in the Capitan reef 

(Permian), New Mexico and Texas, in Friedman, 

G.M., ed., Depositional Environments in Carbonate 

Rocks: Tulsa, OK, SEPM Special Publication 14, 

p. 182-191. 

Esteban, M., and L.C. Pray. 1977. Origin of the pisolite 

facies of the shelf crest, in Hileman, M.E., and 

Mazzullo, S.J., eds., Upper Guadalupian Facies, 

Permian Reef Complex, Guadalupe Mountains, New 

Mexico and West Texas (1977 Field Conference 

Guidebook): Midland, TX, Permian Basin SectionSEPM Publication 77-16, p. 479-486 

Esteban, M. and L.C. Pray. 1983. Pisoids and pisolite 

facies (Permian), Guadalupe Mountains, New Mexico 

and West Texas, in T.M. Peryt, ed., Coated Grains: 

Springer-Verlag, Berlin, p. 503-537. 

Garber, R.A., G.A. Grover, and P.M. Harris. 1989. 

Geology of the Capitan shelf margin – subsurface data 

from the northern Delaware Basin, in P.M. Harris and 

G.A. Grover, eds., Subsurface and outcrop 

examination of the Capitan shelf margin, northern 

Delaware Basin: Society of Economic Paleontology 

and Mineralogy (SEPM), Core Workshop no. 13, San 

Antonio, TX, p. 3-269. 

Hayes, P.T. 1974. Geology of the Carlsbad Caverns East 

Quadrangle, New Mexico: U.S.G.S. Map GQ-98, scale 

1:62,500. 

Hayes, P.T., and R.L. Koogle. 1958. Geology of the 

Carlsbad Caverns West Quadrangle, New MexicoTexas: U.S.G.S. Map GQ-112, scale 1:62,500. 

Hill, C.H. 1987. Geology of Carlsbad Cavern and other 

caves in the Guadalupe Mountains, New Mexico and 

Texas: New Mexico Bureau of Mines and Mineral 

Resources, Bulletin 117, 150 p. 
 CAVE Geologic Resource Evaluation Report 37

Hill, C.A. 1991. Sulfuric acid speleogenesis of Carlsbad 

Cavern and its relationship to hydrocarbons, Delaware 

Basin, New Mexico: American Association of 

Petroleum Geologists Bulletin, v. 74, p. 1685-1694. 

Hill, C. 1996. Geology of the Delaware Basin Guadalupe, 

Apache, and Glass Mountains New Mexico and West 

Texas: Permian Basin Section – SEPM, Publication 96-

39, 480 p. 

Jagnow, D.H. 1979. Cavern development in the 

Guadalupe Mountains: Cave Research Foundation, 

Columbus, Ohio. 

Kendall, C.G.St.C. 1969. An environmental reinterpretation of the Permian evaporite-carbonate 

shelf sediments of the Guadalupe Mountains: 

Geological Society of America Bulletin, v. 80, p. 2503-

2526. 

King, P.B. 1948. Geology of the southern Guadalupe 

Mountains, Texas: U.S.G.S. Professional Paper 215, 

183 p. 

Kiver, E.P. and D.V. Harris. 1999. Geology of U.S. 

Parklands: John Wiley & Sons, Inc., New York, p. 177-

189. 

Lee, W.T. 1924. A visit to Carlsbad Caverns: National 

Geographic Magazine, v. 45, no. 1, p. 1-40. 

Mazzullo, L.J., and B.S. Brister. 2001. Keys to successful 

Morrow Formation exploration, southeastern New 

Mexico: Abstract, American Association of Petroleum 

Geologist Bulletin, Southwest Section meeting, Vol. 85, 

p. 388. 

National Park Service 1993. “Report of the Guadalupe 

Caverns Geology Panel to the National Park Service,” 

by Harvey R. DuChene, David H. Jagnow, Lloyd Pray, 

and J. Michael Queen: On file at NPS Southwest 

Region Office, Santa Fe, NM. 

National Park Service. 1996. Final General Management 

Plan Environmental Impact Statement: US 

Department of Interior, National Park Service, NPS D66A, Denver Service Center, Denver, CO, 286 p. 

New Mexico Institute of Mining and Geology. An 

Introduction and Virtual Geologic Field Trip to the 

Permian Reef Complex, Guadalupe and Delaware 

Mountains New Mexico-West Texas: http://www. 

geoinfo.nmt.edu/staff/scholle/guadalupe.html, access 

November 2005. 

Palmer, A.N., and M.V. Palmer. 2000. Hydrochemical 

interpretation of cave patterns in the Guadalupe 

Mountains, New Mexico: National Speleological 

Society, Journal of Cave and Karst Studies, p. 91-108. 

Peterson, J.A. 1980. Permian paleogeography and 

sedimentary provinces, west central United States, in 

Thomas D. Fouch and Esther R. Magathan, eds., 

Paleozoic Paleogeography of the West-Central United 

States: Rocky Mountain Section, SEPM (Society for 

Sedimentary Geology), p. 271-292. 

Polyak V.J., W.C. McIntosh, P. Provencio, and N. Güven. 

1998. Age and Origin of Carlsbad Caverns and related 

caves from 40 Ar/ 39 Ar of alunite: Science, v. 279, 

p.1919-1922. 

Santucci, V.L., J. Kenworthy, and R. Kerbo. 2001. An 

Inventory of Paleontological Resources Associated 

with National Park Service Caves: Geologic Resources 

Division Technical Report NPS/NRGRD/GRDTR01/02, p. 8-11. 

Sarg, J.F. 1981. Petrology of the carbonate-evaporite 

facies transition of the Seven Rivers Formation 

(Guadalupian, Permian), southeast New Mexico: 

Journal of Sedimentary Petrology, v. 51, p. 73-95. 

Sarg, J.F. 1985. Permian shelf calcrete, Shattuck Member, 

Queen Formation (southeast New Mexico) – shelfal 

expression of Middle Guadalupian fall in sea level: 

West Texas Geological Society, v. 24, no. 8, p. 8-16. 

Sarg, J.F. 1986. Facies and stratigraphy of upper San 

Andres basin margin and lower Grayburg inner shelf, 

in G.E. Moore and G.L. Wilde, eds., San 

Andres/Grayburg Formations, Guadalupe Mountains, 

New Mexico and Texas: Society of Economic 

Paleontologists and Mineralogists, Permian Basin 

section, Publ. 86-25, p. 83-93. 

Scholle, P.A. and D.J.J. Kinsman. 1974. Aragonitic and 

high-Mg calcite caliche from the Persian Gulf — a 

modern analog for the Permian of Texas and New 

Mexico: Journal of Sedimentary Petrology, v. 44, p. 

904-916. 

Scotese, C.R., R.K. Bambach, C. Barton, R. Van Der Voo, 

and A.M. Ziegler. 1979. Paleozoic base maps: Journal 

of Geology, v. 87, p. 217-235. 

Texas Bureau of Economic Geology, University of Texas. 

2005. Project Summary of the Delaware Mountain 

Group: www.beg.utexas.edu/resprog/ delbas/ 

summary.htm, access November 2005. 

Van der Heijde, P.K.M., K.E. Kolm, H. Dawson, and M. 

Brooke. 1997. Determining water infiltration routes 

from structures located above Carlsbad Cavern, 

Carlsbad Caverns National Park, Carlsbad, New 

Mexico: International Ground Water Modeling 

Center, Colorado School of Mines, 88 p. 
 NPS Geologic Resources Division 38 

Ward, R.F., C.G. Kendall, and P.M. Harris. 1986. Upper 

Permian (Guadalupian) facies and their association 

with hydrocarbons, Permian Basin, West Texas and 

New Mexico: American Association of Petroleum 

Geologists Bulletin, v. 70, no. 3, p. 239-262. 

Williamson, C.R. 1979. Deep-sea sedimentation and 

stratigraphic traps, Bell Canyon Formation (Permian), 

Delaware Basin, in N.M. Sullivan, ed., Guadalupian 

Delaware Mountain Group of West Texas and 

Southeast New Mexico: Permian Basin Section – 

SEPM, Publication 79-18, p. 39-74. 
 CAVE Geologic Resource Evaluation Report 39

Appendix A: Geologic Map Graphic 

The following page provides a preview or “snapshot” of the geologic map for Voyageurs 

National Park. For a poster size PDF of this map or for digital geologic map data, please 

see the included CD or visit the GRE publications webpage: 

http://www2.nature.nps.gov/geology/inventory/gre_publications.cfm. 

 CAVE Geologic Resource Evaluation Report 41

Appendix B: Scoping Summary 

The following excerpts are from the GRE scoping summary for Carlsbad Caverns 

National Park. The scoping meeting occurred on March 6-8, 2001; therefore, the contact 

information and Web addresses referred to herein may be outdated. Please contact the 

Geologic Resources Division for current information. 

A Geologic Resources Inventory (GRI) workshop was 

held for both Carlsbad Caverns (CAVE) and Guadalupe 

Mountains (GUMO) National Parks March 6-8, 2001. 

The purpose was to view and discuss the park’s geologic 

resources, to address the status of geologic mapping for 

compiling both paper and digital maps, and to assess 

resource management issues and needs. Cooperators 

from the NPS Geologic Resources Division (GRD), 

Natural Resources Information Division (NRID), 

Carlsbad Caverns, Guadalupe Mountains, as well as 

academics from the Colorado School of Mines, the New 

Mexico Bureau of Mines and Mineral Resources and the 

Texas Bureau of Economic Geology were present for the 

workshop. 

This involved single-day field trips to view the geology of 

both GUMO (led by Gorden Bell, Mike Gardner, and 

Charlie Kerans) and CAVE (led by Paul Burger), as well 

as another full-day scoping session to present overviews 

of the NPS Inventory and Monitoring (I&M) program, 

the GRD, and the on-going GRI. Round table 

discussions involving geologic issues for both GUMO 

and CAVE included the status of geologic mapping 

efforts, interpretation, paleontologic resources, sources 

of available data, and action items generated from this 

meeting. 

Overview of Geologic Resources Inventory (GRI) 

The NPS GRI has the following goals: 

1. to assemble a bibliography of associated geological 

resources for NPS units with significant natural 

resources; “GRBIB”, 

2. to compile and evaluate a list of existing geologic maps 

for each unit, 

3. to develop digital geologic map products, and 

4. to complete a geological report that synthesizes much 

of the existing geologic knowledge about each park. 

It is stressed that the emphasis of the inventory is not to 

routinely initiate new geologic mapping projects, but to 

aggregate existing "baseline" information and identify 

where serious geologic data needs and issues exist in the 

National Park System. In cases where map coverage is 

nearly complete (ex. 4 of 5 quadrangles for Park “X”) or 

maps simply do not exist, then funding may be available 

for geologic mapping. 

After introductions by the participants, Tim Connors 

presented overviews of the Geologic Resources Division, 

the NPS I&M Program, the status of the natural resource 

inventories, and the GRI in particular. 

He also presented a demonstration of some of the main 

features of the digital geologic database. 

Geologic Mapping 

The USGS has published Professional Papers (PP) on 

both the Texas and New Mexico portions of the 

Guadalupe Mountains. PP-215 (by Phil King, circa 1948) 

covers the Texas portion of the Guadalupes (GUMO) 

and contains a geologic map at 1:48,000 scale that ends at 

the Texas state line. PP-446 (by Phil Hayes 1964) covers 

the New Mexico portion of the Guadalupe Mountains 

(CAVE) and contains a geologic map at 1:62,500 scale. 

CAVE staff have supplied GRI staff with a preliminary 

digitized version of this map that needs some additional 

attribution. Both were excellent, very comprehensive 

publications for their day and still are quite useful even 

though interpretations have been refined since their 

publication. 

The USGS has also published a few other maps that 

cover the CAVE area. MF-1560-a ("Mineral Resource 

Potential and Geologic Map of the Guadalupe 

Escarpment Wilderness Study Area, Eddy County, New 

Mexico") is mapped at 1:24,000 scale. GQ-112 and GQ98 are also published as separate maps that predate PP446 and are both at 1:62,500 scale. Of note, however, is 

that MF-1560-a only covers the southwestern-most 

portion of CAVE. 

All of these maps were considered worthy of digitizing as 

they represent some of the best sources of existing 

"baseline" data. GRI staff will incorporate the 

digitization of these maps into their future workplan. 

Also, the Colorado School of Mines (under the direction 

of Mike Gardner), has been concentrating their efforts 

on large-scale mapping of the Permian Reef at GUMO, 

specifically the Brushy Canyon unit. They have digital 

versions of this mapping in ArcView format and are 

willing to share it with the NPS. 

Desired Enhancements to the Existing Maps 

CAVE 1:24,000 scale mapping: Paul Burger would like to 

see the six main "quadrangles of interest" for CAVE 

(Queen, Serpentine Bends, Carlsbad Caverns, Gunsight 

Canyon, Grapevine Draw, and Rattlesnake Spring) 

mapped at 1:24,000 scale. At this time, it is not known if 

Hayes compilation map at 1:62,500 scale was compiled 

from original 1:24,000 scale maps. If they were, then the 

data is essentially already there. GRD will attempt to 

discern if this is true for the Hayes map. 
 NPS Geologic Resources Division 42 

Peter Scholle mentioned that the New Mexico GS will be 

producing a geologic map of the Carlsbad West 

quadrangle at 1:24,000 scale, but this is not one of the 

parks quadrangles of interest, as it lies directly west of 

the actual town of Carlsbad, which is northeast of CAVE 

proper. He also thought that the Hayes maps need 

refinement in the CAVE area. 

Paul would also like to see more detailed mapping of the 

Yates-Tansill contact because it is the location from 

which water emanates to become the parks water supply.

Suggested improvements to the existing maps 

• Refinements to King's maps would involve splitting 

out the Carlsbad Group into three formations (Yates, 

Tansill, Seven Rivers formations) to seamlessly edgematch that of Hayes map (and hence eliminate the 

New Mexico/Texas "boundary fault"). Gorden Bell 

thought that aerial photography and satellite photos 

could be used to do this with minimal field checking. 

• Integrate Mike Gardner’s large scale mapping of the 

Western escarpment with the King map for better 

detail for the Brushy Canyon unit members which also 

include some minor faults that are not shown on 

King's maps 

• Work out the subdivision of the Bone Spring versus 

the Cutoff formations where the units are shown but 

the interpretations have changed over time 

• Work out the Victorio Peak-San Andres problem 

which relates to Goat Seep (which is really now known 

as the Grayburg and Queen); 

• Resurveying of roadcuts is desired in and around both 

parks 

• Hazard and rockfall assessments should be conducted, 

although most susceptible areas don't seem to affect 

facilities 

• Essentially re-map approximately one quadrangle 

worth of mapping on Carlsbad Group in GUMO (not 

quad specific); New Mexico Bureau estimates 

~$100,000 to do that work 

Use of LIDAR technology for higher resolution 

Charlie Kerans and Mike Gardner would see the use of 

LIDAR technology as a great asset to refining any 

mapping and future research, and would like to have this 

data available for the Guadalupe Mountains and 

Delaware Basin in the very near future. 

They "rough" estimated the data acquisition at between 

$60,000 for a "poor-man's DEM" to $100,000 for full 

LIDAR coverage. 

Various ideas were proposed on how to go about 

accomplishing this task and need to be followed up on by 

the cooperators. Joe Gregson told the group of the 

Department of the Interior (DOI) high priority program 

to obtain funds through regions to obtain such LIDAR 

information. He mentioned that leveraging with adjacent 

land managing agencies (Forest Service, BLM, etc) often 

is the most successful way to acquire funding for 

obtaining this technology 

Mike Gardner made the suggestion that the Colorado 

School of Mines, NPS, and Texas and New Mexico 

Geologic Bureaus cost share to acquire the LIDAR data 

for the region. 

The NPS could not guarantee such funding allocations 

for FY-2001, but Joe said he would talk to Ingrid Langraf 

(USGS) about any available funding and would report 

back to the group at a later time on what he finds out. 

Here is what Joe was able to find out as of March 14, 

2001: 

"At the GUMO/CAVE geologic resources inventory 

scoping workshop, the group expressed interest in 

obtaining LIDAR data for the parks and adjacent area to 

support geologic mapping, research, and resource 

management. Here is what I found out about getting high 

resolution LIDAR elevation data for the parks and 

Delaware Mtns. via the NPS/USGS agreement. 

“The USGS does not do a direct 50/50 cost share on 

LIDAR as with other base cartography but does have 

contractors available that can fly the area and supply the 

data. Right now, the ball park cost is about $10K per 

quadrangle. Contiguous GUMO and CAVE coverage 

would require about 15-16 quads plus 6-8? quads 

(guessing) for the Colo. School of Mines (CSM) study 

area. That puts the project costs in the $200K-$250K 

range. The best avenue for funding the project (at least 

for the NPS part) appears to be the Dept. of Interior 

High Priority Program which annually funds data 

projects for DOI bureaus. Through the NPS 

Intermountain Region, CAVE and GUMO park staff can 

request high resolution elevation data with requirements 

for LIDAR. If the parks can get other DOI bureaus 

(BLM, BOR, BIA, USGS, etc.) to also request the data, it 

has a very good chance of being funded. Unfortunately, 

the DOI Program call is past for this year, and it runs a 

year in advance (i.e., a request next year would get put 

into work in FY 2003 at the earliest). 

“I know this does not address the immediate needs of 

CSM that were discussed at the workshop, but it is the 

best that I could come up with at the moment. If anyone 

has other ideas for data sources or funding and wishes to 

pursue this further, let me know." 

Digital Geologic Map Coverage 

As stated earlier, it was agreed upon by the consensus of 

the group that the King and Hayes maps were worthy of 

digitization with the caveat of the "Desired 

Enhancements" listed above. Once the maps exist in a 

digital format they are easier to refine both in the field 

and electronically. 

GRI staff in Denver will attempt to accomplish this 

digitization in their workplan in FY-2002. Of note, is the 

existence of digital linework for the Hayes 1964 map in 

PP-446, but there is no accompanying metadata. GRI 

staff would also like to get it attributed as per their NPS 
 CAVE Geologic Resource Evaluation Report 43

digital geologic map model. Dave Roemer (CAVE-GIS) 

will need to be consulted for more specifics on metadata 

for this coverage. 

Charlie Kerans thought that another additional piece of 

information that should be tied to any digital geologic 

database would be measured stratigraphic sections that 

could be georeferenced and brought up in a GIS. This 

should be easy to add in to the NPS Digital Geologic 

Database Model. 

Other desired GIS data 

General needs: Paul Burger would like to see a GIS 

coverage for linear features for CAVE (Kim Cunningham 

and Dave Yagnow) for the Dark Canyon Environmental 

Impact Statement (EIS). Additionally, he is interested in a 

delineated watershed for Rattlesnake Springs, which is 

the sole water supply for city of Carlsbad. Ground 

Penetrating Radar (GPR) or an electromagnetic survey 

could be used to delineate this. 

Soils: Pete Biggam (GRD Soil Scientist) supplied the 

following information in reference to soils for both 

parks: 

"We currently have in place an Interagency Agreement 

with the TX - NRCS to map all NPS units in Texas, based 

upon an estimated completion by 2005 (as funding 

allows) 

“We are estimating that we might initiate soils mapping at 

GUMO in 2003, and would be utilizing the NRCS soil 

survey crew that is currently located in El Paso, TX. This, 

of course, is dependent on funding being provided by 

NPS I&M for this effort. We would also be looking at 

initiating soils mapping at CAVE and WHSA in a similar 

timeframe. 

“We operate similar to the GRI, we would schedule a soil 

scoping session, look at soils research that was already 

performed at GUMO, map it to National Cooperative 

Soil Survey Standards with local input from GUMO in 

regards to their soil resource management concerns. 

“Products would be a digital soils map, digital soil 

attributes, metadata, soil report, as well as potentially 

some soil information/education products which could 

be incorporated into GUMO's interpretive program. 

There would be data that would be utilized within the 

NPD GIS Theme manager as well, similar to what is 

being done with GRI. 

“We would also have a ‘last acre mapped session’, where 

we would have a soils field tour of the park." 

Geologic Hazards 

GUMO has a published hazards map from R.R. 

Railsback (University of Texas at Dallas) that was done 

in 1976. It has been digitized by Parsons Engineering. It is 

titled Geologic Hazards in the Pine Springs Canyon area, 

Guadalupe Mountains National Park. 

Vicky Magnis (NPS-IMR GIS) apparently has this data in 

digital format from Parsons Engineering and it is 

currently being tracked down by Tim Connors. It is 

unknown what format the data is in (AutoCAD, ArcView 

etc.). Vicki will be working with GUMO staff on the GIS 

portion of their General Management Plan (GMP). 

Paleontology 

Greg McDonald (GRD Paleontologist) would like to see 

an encompassing, systematic Paleontological inventory 

for both GUMO and CAVE describing the known 

resources in both parks with suggestions on how to best 

manage these resources. 

Other Sources of Data 

• Charley Kerans did a presentation on “Hierarchical 

Stratigraphic Analysis of a Carbonate Platform, 

Permian of the Guadalupe Mountains”. He mentioned 

that much of this data will be out in CD-ROM in the 

near future. It will likely be available from the Texas 

Bureau of Economic Geology website 

(http://www.beg.utexas.edu). GRI staff are interested 

in obtaining a copy of this once it is available to the 

public. 

• The Colorado School of Mines has a website for 

research on the slope and basin consortium at 

http://www.mines.edu/Academic/geology/sbc/. 

Interpretation 

Numerous topics regarding interpretation of geologic 

resources were discussed. Among these included: 

• ·The Permian Reef complex should be better utilized 

in both parks as the major interpretive focus, and the 

tie of the Guadalupe Escarpment between both parks 

should be made to illustrate the importance of the 

Capitan Reef as a world-class feature that is unique to 

this area alone. This should also serve to illustrate the 

GUMO-CAVE story to the regional picture for 

Permian time. 

• Make better use of park trails to showcase and 

interpret the park geology for visitors 

• A Reef diorama in each visitor center showing modern 

analogs and the process of reef building 

• Mike Gardner has offered to assemble a Bone SpringsShumard trail guide trail for GUMO (for free) 

• Make better use of the story of P.B. King’s 

"interpretations" of the reef as a major contribution to 

the science of geology in general. 

Geologic Report 

An encompassing report on each parks geology is a major 

focus of the GRI. To date both the King and Hayes 

Professional Papers fulfill a major role in describing the 

regional geology, but are highly technical and not written 

for the average NPS Resource Manager. 

To this end, it was generally agreed that simpler, toned 

down reports will need to be written for both CAVE and 

GUMO. The next task is to find enthusiastic report 
 NPS Geologic Resources Division 44 

writers to tackle this chore. Both states geologic bureaus 

(Texas and New Mexico) have offered their assistance in 

reviewing such reports in final format, supplying maps 

and graphics on the local geology in their existing 

publications, and offering their general assistance to the 

NPS. Peter Scholle says his agency is already doing a 

publication on the geology of New Mexico's State Parks. 

Paul Burger was enthusiastic about writing such a report 

for CAVE, and thought this would be a good use of his 

time as the parks geologist. 

Jan Wobbenhorst suggested GUMO geologist Gorden 

Bell as the logical choice to write such a report for 

GUMO, as he is the local NPS expert on the geology. 

Scoping Session Attendees: 

NAME AFFILIATION PHONE E-MAIL 

Fred Armstrong NPS, GUMO 

Natural Resources 

915-828-3251 

ext. 251 Fred_armstrong@nps.gov 

Gorden Bell NPS, GUMO Geologist 915-828-3251 

ext. 249 Gorden_bell@nps.gov 

Paul Berger NPS, CAVE Geologist 505-785-2232 

ext. 394 Paul_Burger@nps.gov 

Doug Buehler NPS, GUMO Interpretation 915-828-3251 

ext. 105 Doug_buehler@nps.gov 

Tim Connors NPS, GRD (303) 969-2093 Tim_Connors@nps.gov 

Steve Fryer NPS, NRID 970-225-3584 Steve_Fryer@nps.gov 

Mike Gardner Colorado School of Mines 303-384-2042 Mgardner@mines.edu 

John Graham NPS, CSU 970-225-6333 rockdoc250@comcast.net 

Joe Gregson NPS, NRID (970) 225-3559 Joe_Gregson@nps.gov 

Bruce Heise NPS, GRD (303) 969-2017 Bruce_Heise@nps.gov 

Charles Kerans Bureau of Economic Geology 

Univ. of Texas at Austin 512-471-1368 Charles.kerans@beg.utexas.edu 

Vicki Magnis NPS, IMR GIS 303-969-2962 Viktoria_magnis@nps.gov 

Greg McDonald NPS, GRD 303-969-2821 Greg_McDonald@nps.gov 

Dale Pate NPS, CAVE Cave Specialist 505-785-2232 Dale_pate@nps.gov 

Greer Price New Mexico Bureau of Mines 

and Mineral Resources 505-835-5752 Gprice@gis.nmt.edu 

Dave Roemer NPS, CAVE GIS Dave_roemer@nps.gov 

Peter Scholle New Mexico Bureau of Mines 

and Mineral Resources 505-835-5302 Pscholle@gis.nmt.edu 

Jan Wobbenhorst NPS, GUMO 

Chief of Natural Resources 

915-828-3251 

ext. 109 Jan_wobbenhorst@nps.gov 
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. 

Carlsbad Caverns National Park 

Geologic Resource Evaluation Report 

Natural Resource Report NPS/NRPC/GRD/NRR—2007/003 

NPS D-139, June 2007 

National Park Service 

Director • Mary A. Bomar 

Natural Resource Stewardship and Science 

Associate Director • Michael A. Soukup 

Natural Resource Program Center 

The Natural Resource Program Center (NRPC) is the core of the NPS Natural Resource Stewardship and 

Science Directorate. The Center Director is located in Fort Collins, with staff located principally in 

Lakewood and Fort Collins, Colorado and in Washington, D.C. The NRPC has five divisions: Air 

Resources Division, Biological Resource Management Division, Environmental Quality Division, Geologic 

Resources Division, and Water Resources Division. NRPC also includes three offices: The Office of 

Education and Outreach, the Office of Inventory, Monitoring and Evaluation, and the Office of Natural 

Resource Information Systems. In addition, Natural Resource Web Management and Partnership 

Coordination are cross- cutting disciplines under the Center Director. The multidisciplinary staff of NRPC 

is dedicated to resolving park resource management challenges originating in and outside units of the 

national park system. 

Geologic Resources Division 

Chief • David B. Shaver 

Planning Evaluation and Permits Branch Chief • Carol McCoy 

Credits 

Author • Dr. John Graham

Editing • Sid Covington, Ron Kerbo, and Melanie Ransmeier 

Digital Map Production • Anne Poole and T. T. Hayes 

Map Layout Design • Andrea Croskrey
Geologic Resources Division 

Natural Resource Program Center 

P.O. Box 25287 

Denver, CO 80225 

http://www.nature.nps.gov/geology/inventory/ 

(303) 969-2090 

EXPERIENCE YOUR AMERICATM 

National Park Service 

U.S. Department of the Interior