For the more information about the geologic resources of the National Park Service, please visit http://www.nature.nps.gov/geology/.


Geologic Illustrations

PaleoceanographyGlacial drift aquiferSubduction zone All things glacier Speleothems formation Fault types

 

Fundamental geological concepts and processes can be difficult to comprehend. Good illustrations of these processes can demonstrate key earth systems concepts and recreate past events.

The illustrations on this page can be downloaded and used for classroom instruction or as supplementary educational material. Many of the graphics illustrate basic geological concepts while others are specific to a certain park or region.

 

 

 


  • Geologic Processes
  • Plate Tectonics
  • Volcanics
  • Glacial
  • Caves and Karst

Geologic Processes

Mass Wasting

Mass wasting

Types of slope movement. Different categories of slope movement are defined by material type, nature of the movement, rate of movement, and moisture content. 1.10 MB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University modified from Varnes, D. J. 1978. Landslides: analysis and control.

Freeze-thaw Weathering

Freeze thaw weathering

Diagram shows the process of freeze-thaw weathering and subsequent formation of talus piles in a typical outcrop. 60 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Bajada Formation

Bajada formation

An illustration of the formation of a bajada from the overlapping of alluvial fans, debris-flow deposits, and outwash flood deposits along the Sierra Nevada Front in the vicinity of Manzanar National Historic Site. 75 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Basin and Range Topography

Topography of Basin and Range

Diagram illustrating the formation of basin and range topography during extension of the Earth's crust along a system of normal faults. 70 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Meandering Stream Evolution

Oxbow lake

Evolution of a meandering stream includes the following: (1) stream channel within meander belt; (2) development of a nearly closed meander loop; (3) high water flowing across the neck of loop, making a cutoff; (4) deposition of sediment sealing the loop and creating an oxbow lake. 221 KB JPEG
Source: Phil Reiker, NPS Geologic Resources Division.

Types of Sand Dunes

Types of sand dunes

Types of sand dunes. Sand supply, wind direction, and interactions among groundwater salinity, topographic elevation, and vegetation growth affect dune morphology. 91 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University after Fryberger, S. G., L. F. Krystinik, and C. J. Schenk. 1990. Modern and ancient eolian deposits: Petroleum Exploration and Production; and McKee, E. D. 1966. Structures of dunes at White Sands National Monument, New Mexico (and a comparison with structures of dunes from other selected areas).


Barchanoid Dune Morphology

Barchanoid dune morphology

Types of sand dunes. Sand supply, wind direction, and interactions among groundwater salinity, topographic elevation, and vegetation growth affect dune morphology. Graphic illustrates barchanoid dune morphologies. 303 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University after Fryberger, S. G., L. F. Krystinik, and C. J. Schenk. 1990. Modern and ancient eolian deposits: Petroleum Exploration and Production; and McKee, E. D. 1966. Structures of dunes at White Sands National Monument, New Mexico (and a comparison with structures of dunes from other selected areas).

Rock Cycle

Rock cycle

Rock cycle diagram showing the associated geologic processes where the three types of rock are found: sedimentary, igneous, and metamorphic. 163 KB PDF
Source: NPS in collaboration with USGS


Bowen's Reaction Series

Bowens Reaction

In the early 1900's N. L. Bowen determined that different minerals crystallize at different temperatures during the cooling of magma. This chart demonstrates the reaction rates. 273 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.



 

Plate Tectonics

Fault Types

Fault types

Learn what the different fault types are and what the difference between the Hanging Wall and Foot Wall in these illustrations. 310 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University

Types of Folds

Types of folds

Rocks deform under stress from crustal movement and sometimes bend the rock layers into folds. These illustrations demonstrate the types of folds and how to differentiate between the ages of the rock layers. 173 KB JPEG
Source: R. J. Lillie. 2005. Parks and Plates.


Map of Tectonic Plates

Plate tectonic map

The Earth is made up of roughly a dozen major plates and several minor plates. These plates are constantly moving, some as fast as 15 centimeters a year! 533 KB JPEG
Modified from: R. J. Lillie. 2005. Parks and Plates.

Convergent Plate Boundary

Convergent plate boundary

When two plates collide together it forms a convergent plate boundary. At a convergent plate boundary the older, more dense crust will sink, or "subduct" under the other. 113 KB JPEG
Source: United States Geological Survey


Subduction Zone

Subduction zone angles

At a convergent plate boundary the older, more dense crust will sink, or "subduct" under the other. There can be a Normal-Angle Subduction and a Low-Angle Subduction. 111 KB JPEG
Source: R. J. Lillie. 2005. Parks and Plates.

Cascadia Subduction Zone

Cascadia Subduction Zone

At the Cascadia Subduction Zone mountains in the coastal range differ physiographically from the volcanic mountains in the Cascade Mountains.
345 KB JPEG
Source: R. J. Lillie. 2005. Parks and Plates.


Appalachian Paleogeography

Appalachian paleogeography

The Appalachian Mountains formed during the Paleozoic Era as the supercontinent Pangaea was assembled. During the Mesozoic and Cenozoic Eras, Pangaea splits apart, forming the Atlantic Ocean and eroding the Appalachian Mountains. Illustrations modified from Ron Blakey, Colorado Plateau Geosystems, Arizona, USA.

Paleozoic Era Paleogeography (1011 KB JPEG)
Mesozoic & Cenozoic Era Paleogeography (1.07 MB JPEG)

Fault-Block Mountains

Fault-block mountains

Through extensional forces brittle crust can break into large blocks. Grabens drop, forming basins, and large blocks that are uplifted create horsts, or ranges.
36 KB JPEG
Source: R. J. Lillie. 2005. Parks and Plates.


Accreted Terrane of Alaska

accreted terrane

A terrane accretion is the result of sediment and rocks piling onto a plate at a convergent boundary. This is a cross-sectional view of southern Alaska's accreted terrane. 176 KB JPEG
Source: R. J. Lillie. 2005. Parks and Plates.

Basin and Range Topography

Basin and Range

Diagram illustrating the formation of basin and range topography during extension of the Earth's crust along a system of normal faults. 70 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


The Teton Fault

Teton Fault width=

The Teton Range rises more than 2,100 m above the floor of Jackson Hole. This range is part of the upthrown footwall block of the fault, while Jackson Hole is situated on the downdropped hanging-wall block. 74 KB JPEG
Modified from: R. J. Lillie. 2005. Parks and Plates by Trista L. Thornberry-Ehrlich, Colorado State University.

Great Basin Horst and Graben

Great Basin horst and graben

Crustal extension caused the Great Basin to rift, creating horsts, such as Snake Range, and grabens, such as Spring Valley. The grabens filled with sediment eroded from the adjacent horsts. 86 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Island Arc Setting

Island arc setting

An island-arc setting includes a chain of offshore, island volcanoes above a subducting plate. The back-arc is located opposite the trench and subducting plate, behind the chain of volcanoes called an "island arc". 159 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Hotspot

Hotspot

This graphic shows the evolution of a chain of islands over stationary mantle plume (hotspot) within Earth's crust.
222 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Pacific Ocean Hotspots

Pacific Ocean Hotspot

Tectonic setting of the Pacific Plate with selected hotspots indicated. The "kink" between the Emperor Seamounts and Hawaiian Islands chain shows how the direction of plate motion changed while the Hawaiian hotspot remained stationary. 730 KB JPEG
Compile by Jason Kenworthy (NPS Geologic Resources Division) from ESRI Arc Image Service Imagery Prime World 2D, with information from fig. 2 in Clouard, V., and A. Bonneville. 2001. How many Pacific hotspots are fed by deep-mantle plumes?

Seismicity Map

Seismicity Map

Seismicity map of Central America and the Caribbean where colored dots record 16 years (1990-2006) of earthquakes and their depths.
811 KB JPEG
Modified from U.S. Geological Survey. 2009. World seismicity maps: Central America.


Tectonic Evolution

Tectonic Evolution

Illustration of the plate tectonic activity of the eastern margin of North America (near Connecticut) throughout the Paleozoic Era. The red star on figure E notes the approximate location of Weir Farm National Historic Site. 1.0 MB JPEG
Adapted from: M. E. Coleman. 2005. The Geologic History of Connecticut's Bedrock., by Trista L. Thornberry-Ehrlich, Colorado State University.

Tectonic Evolution: Vermont

Tectonic Evolution: Vermont

Graphic of the evolution of Vermont throughout the Paleozoic. Green star on Panel F indicates the approximate location of Marsh-Billings-Rockefeller National Historical Park. 688 KB JPEG
Adapted from: B. Doolan, 1996. The geology of Vermont., by Trista L. Thornberry-Ehrlich, Colorado State University.



Volcanics

Island Arc Setting

Island arc setting

An island-arc setting includes a chain of offshore, island volcanoes above a subducting plate. The back-arc is located opposite the trench and subducting plate, behind the chain of volcanoes called an "island arc". 159 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Back-arc Basin of the Black Hills

Back-arc basin of Black Hills

The Precambrian tectonic activity in the Black Hills region where the subducting lithosphere (Trans-Hudson Province) is being subducted beneath the Wyoming Archean Province. The Black Hills and Devils Tower National Monument would be located in the Back-arc basin between 1,710 and 1,880 Ma. 70 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Pacific Ocean Hotspots

Pacific Ocean Hotspots

Tectonic setting of the Pacific Plate with selected hotspots indicated. The "kink" between the Emperor Seamounts and Hawaiian Islands chain shows how the direction of plate motion changed while the Hawaiian hotspot remained stationary. 730 KB JPEG
Compile by Jason Kenworthy (NPS Geologic Resources Division) from ESRI Arc Image Service Imagery Prime World 2D, with information from fig. 2 in Clouard, V., and A. Bonneville. 2001. How many Pacific hotspots are fed by deep-mantle plumes?

Hotspot

Hotspot evolution

The evolution of a chain of islands over stationary mantle plume (hotspot) within Earth's crust.
222 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


Hawaiian Hotspot Island Volcanism

Hawaiian hotspot volcanism

Simplified stages of Hawaiian hotspot island volcanism. After volcanism ceases, erosion and subsidence slowly lower the island into the sea. 178 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University, after Stearns, H.T. 1946. Geology of the Hawaiian Islands: Hawaii and Keating, B.H. 1992. Geology of the Samoan Islands.

Shield-stage Volcanism

Shield stage volcanism

Over Time, the Pacific Plate moved over a stationay hotspot, forming shield volcanoes. As volcanoes move away from the hotspot they become inactive, subside and erode, and drop below sea level. This image shows the ages, in millions of years, of the Hawaiian Islands. 395 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University after Geological Oceanography Program


Caldera Formation

Caldera Formation

Simplified stages of Hawaiian hotspot island volcanism. After volcanism ceases, erosion and subsidence slowly lower the island into the sea. 240 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University, after Stearns, H.T. 1946. Geology of the Hawaiian Islands: Hawaii and Keating, B.H. 1992. Geology of the Samoan Islands.

Isle Royale: Evolution of Landscape I

Shield stage volcanism

Evolution of the landscape in the Isle Royale area from the Precambrian rifting and volcanism through the early Paleozoic deposition of post-volcanic sediments. 98 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University


Isle Royale: Evolution of Landscape II

Caldera Formation

Evolution of the landscape in the Isle Royale area continued from the Late Precambrian - Early Cambrian thrust faulting through the the Pleistocene ice ages to the present day landscape. 101 KB JPEG Source: Trista L. Thornberry-Ehrlich, Colorado State University



Glacial

Glacial Features and Deposits

Glacial features and deposits

This graphic illustrates features and deposits associated with glaciers; not every glacially altered landscape contains all of these features or deposits. 741 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Glacier Features

Glacier features

An illustration of a retreating glacier with a recent terminal moraine and a broad space between the moraine and the glacial front.. 439 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.


All Things Glacial

All things glacier

This schematic graphic illustrates "classic" landforms common to areas that were glaciated. Not every landscape contains examples of every feature. 623 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Yosemite Glacier Features

Yosemite glacier features

A comparison of a schematic diagram of alpine glacial features (A) and glacial features associated with the northeast side of Mr. Conness in Yosemite National Park (B). 788 KB JPEG
Source for Graphic A: Trista L. Thornberry-Ehrlich, Colorado State University, and Rebecca Port (NPS Geologic Resources Division).
Source for Graphic B: NPS Photo by Greg Stock
.


Drumlin & Roche Moutonnée

Drumlin

Schematic graphic of drumlin and roche moutonnée formation. Not the difference in glacial flow direction versus resulting topography. 363 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.



Caves and Karst

Karst Landscape Development

Karst landscape development

Generalized cross-sectional view of the development of a karstic landscape. 639 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

Speleothems Formation

Speleothems features

A generalized diagram of the chemical evolution of seepage from rainfall to the cave environment and the formation of speleothems. "Caprock" may include sandstone and/or shale. 339 KB JPEG
Source f: Trista L. Thornberry-Ehrlich, Colorado State University.


Mammoth Cave National Park

Mammoth Cave levels

There are five levels of major cave formation at Mammoth Cave National Park. As the Green River's base-level was lowered, downcutting occurred until a new stable base-level was reached at lower elevations. Larger passages (listed in green) generally indicate longer periods of cave formation at a particular level. 610 KB JPEG
Source: Trista L. Thornberry-Ehrlich, Colorado State University.



 

Related Links

 

↑ TOP OF PAGE

Last Updated: June 17, 2014