Cenozoic Landscape Evolution of the Southern Rocky Mountains Completed
The Cenozoic Landscape Evolution of the Southern Rocky Mountains Project is a multi-year investigation funded by the National Cooperative Geologic Mapping Program. This project utilizes a combination of geologic mapping, geophysical surveys, basin modeling, and structural, neotectonic, geomorphic, volcanic, stratigraphic, and geochronologic studies to better understand the geologic landscape of the southern Rocky Mountains province.
The southern Rocky Mountains province extends through northern New Mexico, Colorado, and southern Wyoming. This area has a diverse and protracted geologic history dominated by contractional Laramide deformation, attendant basin sedimentation, and Andean-type arc volcanism during the early Cenozoic. In contrast, the Neogene and Quaternary have been dominated by broadly distributed crustal extension and intra-arc basin formation that are concurrent with Rio Grande rifting. The geologic framework of this part of the Rocky Mountains is well mapped and characterized in some places, but emphasis in these areas is commonly placed on narrow geologic time periods or specific tectonic and orogenic episodes. Remarkably, other regions of this mountain province still have not been adequately mapped and studied to accurately define even temporally limited geologic frameworks. Moreover, linkages between past geologic and climatic processes and events, and paleo to recent landscape change have not been fully and systematically explored across the province.
In this project we explore the Cenozoic geologic history of the southern Rocky Mountains region through an integrated study of:
Geophysics and Subsurface Investigation
Plio-Pleistocene Geomorphic Evolution
Fundamental Questions
Some fundamental questions that the project aims to address are:
- How have Neogene and younger crustal extensional strain and volcanism associated with Rio Grande rifting been transferred and distributed across the Southern Rocky Mountains?
- Have this strain and volcanism been influenced by earlier Laramide structures or subduction-related magmatism?
- How have the extensional strain, volcanism, and basin sedimentation controlled the development of landscapes defining the modern physiography of the province?
- How have climatically and tectonically driven events of the Neogene and Quaternary influenced establishment and integration of modern drainage patterns?
Significance
Many of the objectives of this project also address societal issues related to groundwater management, geothermal and traditional energy resources, and seismic hazards. The Southern Rocky Mountains encompass strategic mineral and fossil fuel reserves, agricultural resources, groundwater aquifers, and headwaters of four major intermontane river drainages that sustain and provide energy for a rapidly growing population that currently numbers more than 5 million just in Colorado alone. Linked by the through-flowing rivers (Rio Grande, Arkansas, Colorado, and Platte) along tectonic troughs of the Rio Grande rift or incised mountain valleys, the vitality of intermountain basin and Front Range communities and economies depends on a growing supply of water extracted from complex aquifers, mostly in rift-basin sediments. The groundwater is controlled by the subsurface geology, including basin aquifer thickness, buried faults and basement structure, and fault configurations at the mountain front recharge zones.
Energy resources, in the form of oil, gas, and geothermal, are found in basins or at their margins throughout the southern Rocky Mountain region. In particular, geologic controls on geothermal resources are poorly understood yet there is new impetus for the Rocky Mountain States to investigate and develop these resources.
Finally, the Rio Grande rift is still considered seismically active even though few historic earthquakes have been recorded. Evidence of large-magnitude Quaternary earthquakes with recurrence intervals of 10–140 ka suggests that these faults could be particularly dangerous. Long periods of seismic quiescence allow active fault scarps to be obscured by erosion and make them difficult to map.
Over three-quarters of the proposed study area is administered as public lands, including Rocky Mountain National Park, Great Sand Dunes National Park, Rio Grande del Norte National Park (est. 2013), Bandelier National Monument, National Forests, Bureau of Land Management lands, and US Fish and Wildlife Service wetlands areas. Each year millions of tourists and outdoor enthusiasts visit and depend on these public lands to recreate and enjoy their natural beauty and resources. Managing critical renewable and non-renewable resources, protecting wildlife and ecosystems, and providing viable recreational opportunities are reliant on understanding the underlying geologic controls on water quality and quantity, mineral deposits, fossil fuel reserves, and landscape and ecosystem stability.
Objectives
Cenozoic tectonics, magmatism, surface processes and landscape evolution are linked by geodynamic processes and are manifested geologically at a range of scales. The earth’s surface reflects the complex interplay of global-scale tectonic plate motions, heat flow, mantle anisotropy, crustal heterogeneity, and climate change. The impact of these forces on the earth’s diverse and spatially varying material properties results in a complex response whereby crustal geomorphic evolution can be dramatically influenced by both internal and external factors. The surface expression of tectonic faulting and folding, associated rock uplift, and construction of large volcanic edifices derived from the transient changes in lithospheric heat flow, drives a geomorphic response. This, in concert with climatic influence, can result in dramatic landscape change, including the establishment of new drainage patterns, basin sedimentation rates, and provenance history. Likewise, fault conduits influence emplacement of magma chambers in the shallow crust that, upon eruption, can alter drainage and sedimentation patterns and, in the case of large magmatic fields, influence climate. The primary geologic influences on ecosystem evolution, drainage history, water resources quantity and quality, mineral resource, oil and gas potential, and geohazards are universally linked through coupled surface processes, geomorphic evolution, and geodynamics.
Strategy and Approach
This project investigates the geologic framework and evolution of a broad swath of the Southern Rocky Mountains between northern New Mexico and southern Wyoming, focusing on linkages to Cenozoic landscape development. Initial project efforts concentrate on two key areas at opposite ends of the project footprint that have traditionally been viewed as having distinct, contrasting geologic styles and histories:
- Basins and flanking ranges of the northern Rio Grande rift (northern New Mexico and southern Colorado) dominated by Neogene extensional tectonics, volcanism, and sedimentation and the North-Middle Park region (northern Colorado) dominated by Laramide contractional deformation and sedimentation.
- The North-Middle Park region (northern Colorado) dominated by Laramide contractional deformation and sedimentation.
Early focus in these two regions builds on geologic mapping and investigations conducted on predecessor, National Cooperative Geologic Mapping Program-funded Rio Grande Basins and Colorado Headwaters Basin projects. Moreover, these initial project foci will result in detailed and comprehensive datasets to compare "end-member" tectonic influences and histories and allow opportunities to document under-recognized transitional and overprinted tectonic and magmatic signatures and attendant landscape changes. Project efforts will eventually expand to other uplifted mountain blocks and basins (or "parks") to similarly investigate and document their local geologic frameworks and their influences on landscape evolution.
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado
Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado
Geologic map of the Mount Sherman 7.5' quadrangle, Lake and Park Counties, Colorado
Geologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado
Geologic map of the Sand Creek Pass quadrangle, Larimer County, Colorado, and Albany County, Wyoming
Geologic map of the Fraser 7.5-minute quadrangle, Grand County, Colorado
Geologic Map of the Estes Park 30' x 60' Quadrangle, North-Central Colorado
Geologic Map of the Eaton Reservoir Quadrangle, Larimer County, Colorado and Albany County, Wyoming
Below are publications associated with this project.
A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado
Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains
Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado
Sample descriptions and geophysical logs for cored well BP-3-USGS, Great Sand Dunes National Park and Preserve, Alamosa County, Colorado
Potassium-argon (argon-argon), structural fabrics
Neotectonics and geomorphic evolution of the northwestern arm of the Yellowstone Tectonic Parabola: Controls on intra-cratonic extensional regimes, southwest Montana
40Ar/39Ar Geochronology, Isotope Geochemistry (Sr, Nd, Pb), and petrology of alkaline lavas near Yampa, Colorado: migration of alkaline volcanism and evolution of the northern Rio Grande rift
Advancements in understanding the aeromagnetic expressions of basin-margin faults—An example from San Luis Basin, Colorado
Oblique transfer of extensional strain between basins of the middle Rio Grande rift, New Mexico: Fault kinematic and paleostress constraints
Identifying buried segments of active faults in the northern Rio Grande Rift using aeromagnetic, LiDAR,and gravity data, south-central Colorado, USA
Digital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado
- Overview
The Cenozoic Landscape Evolution of the Southern Rocky Mountains Project is a multi-year investigation funded by the National Cooperative Geologic Mapping Program. This project utilizes a combination of geologic mapping, geophysical surveys, basin modeling, and structural, neotectonic, geomorphic, volcanic, stratigraphic, and geochronologic studies to better understand the geologic landscape of the southern Rocky Mountains province.
The southern Rocky Mountains province extends through northern New Mexico, Colorado, and southern Wyoming. This area has a diverse and protracted geologic history dominated by contractional Laramide deformation, attendant basin sedimentation, and Andean-type arc volcanism during the early Cenozoic. In contrast, the Neogene and Quaternary have been dominated by broadly distributed crustal extension and intra-arc basin formation that are concurrent with Rio Grande rifting. The geologic framework of this part of the Rocky Mountains is well mapped and characterized in some places, but emphasis in these areas is commonly placed on narrow geologic time periods or specific tectonic and orogenic episodes. Remarkably, other regions of this mountain province still have not been adequately mapped and studied to accurately define even temporally limited geologic frameworks. Moreover, linkages between past geologic and climatic processes and events, and paleo to recent landscape change have not been fully and systematically explored across the province.
In this project we explore the Cenozoic geologic history of the southern Rocky Mountains region through an integrated study of:
Geophysics and Subsurface Investigation
Plio-Pleistocene Geomorphic Evolution
Fundamental Questions
Some fundamental questions that the project aims to address are:
- How have Neogene and younger crustal extensional strain and volcanism associated with Rio Grande rifting been transferred and distributed across the Southern Rocky Mountains?
- Have this strain and volcanism been influenced by earlier Laramide structures or subduction-related magmatism?
- How have the extensional strain, volcanism, and basin sedimentation controlled the development of landscapes defining the modern physiography of the province?
- How have climatically and tectonically driven events of the Neogene and Quaternary influenced establishment and integration of modern drainage patterns?
Significance
Many of the objectives of this project also address societal issues related to groundwater management, geothermal and traditional energy resources, and seismic hazards. The Southern Rocky Mountains encompass strategic mineral and fossil fuel reserves, agricultural resources, groundwater aquifers, and headwaters of four major intermontane river drainages that sustain and provide energy for a rapidly growing population that currently numbers more than 5 million just in Colorado alone. Linked by the through-flowing rivers (Rio Grande, Arkansas, Colorado, and Platte) along tectonic troughs of the Rio Grande rift or incised mountain valleys, the vitality of intermountain basin and Front Range communities and economies depends on a growing supply of water extracted from complex aquifers, mostly in rift-basin sediments. The groundwater is controlled by the subsurface geology, including basin aquifer thickness, buried faults and basement structure, and fault configurations at the mountain front recharge zones.
Energy resources, in the form of oil, gas, and geothermal, are found in basins or at their margins throughout the southern Rocky Mountain region. In particular, geologic controls on geothermal resources are poorly understood yet there is new impetus for the Rocky Mountain States to investigate and develop these resources.
Finally, the Rio Grande rift is still considered seismically active even though few historic earthquakes have been recorded. Evidence of large-magnitude Quaternary earthquakes with recurrence intervals of 10–140 ka suggests that these faults could be particularly dangerous. Long periods of seismic quiescence allow active fault scarps to be obscured by erosion and make them difficult to map.
Over three-quarters of the proposed study area is administered as public lands, including Rocky Mountain National Park, Great Sand Dunes National Park, Rio Grande del Norte National Park (est. 2013), Bandelier National Monument, National Forests, Bureau of Land Management lands, and US Fish and Wildlife Service wetlands areas. Each year millions of tourists and outdoor enthusiasts visit and depend on these public lands to recreate and enjoy their natural beauty and resources. Managing critical renewable and non-renewable resources, protecting wildlife and ecosystems, and providing viable recreational opportunities are reliant on understanding the underlying geologic controls on water quality and quantity, mineral deposits, fossil fuel reserves, and landscape and ecosystem stability.
Objectives
Cenozoic tectonics, magmatism, surface processes and landscape evolution are linked by geodynamic processes and are manifested geologically at a range of scales. The earth’s surface reflects the complex interplay of global-scale tectonic plate motions, heat flow, mantle anisotropy, crustal heterogeneity, and climate change. The impact of these forces on the earth’s diverse and spatially varying material properties results in a complex response whereby crustal geomorphic evolution can be dramatically influenced by both internal and external factors. The surface expression of tectonic faulting and folding, associated rock uplift, and construction of large volcanic edifices derived from the transient changes in lithospheric heat flow, drives a geomorphic response. This, in concert with climatic influence, can result in dramatic landscape change, including the establishment of new drainage patterns, basin sedimentation rates, and provenance history. Likewise, fault conduits influence emplacement of magma chambers in the shallow crust that, upon eruption, can alter drainage and sedimentation patterns and, in the case of large magmatic fields, influence climate. The primary geologic influences on ecosystem evolution, drainage history, water resources quantity and quality, mineral resource, oil and gas potential, and geohazards are universally linked through coupled surface processes, geomorphic evolution, and geodynamics.
Strategy and Approach
This project investigates the geologic framework and evolution of a broad swath of the Southern Rocky Mountains between northern New Mexico and southern Wyoming, focusing on linkages to Cenozoic landscape development. Initial project efforts concentrate on two key areas at opposite ends of the project footprint that have traditionally been viewed as having distinct, contrasting geologic styles and histories:
- Basins and flanking ranges of the northern Rio Grande rift (northern New Mexico and southern Colorado) dominated by Neogene extensional tectonics, volcanism, and sedimentation and the North-Middle Park region (northern Colorado) dominated by Laramide contractional deformation and sedimentation.
- The North-Middle Park region (northern Colorado) dominated by Laramide contractional deformation and sedimentation.
Early focus in these two regions builds on geologic mapping and investigations conducted on predecessor, National Cooperative Geologic Mapping Program-funded Rio Grande Basins and Colorado Headwaters Basin projects. Moreover, these initial project foci will result in detailed and comprehensive datasets to compare "end-member" tectonic influences and histories and allow opportunities to document under-recognized transitional and overprinted tectonic and magmatic signatures and attendant landscape changes. Project efforts will eventually expand to other uplifted mountain blocks and basins (or "parks") to similarly investigate and document their local geologic frameworks and their influences on landscape evolution.
- Maps
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map boundaries were drawn to cover all of the “Poncha mountainGeologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado
The Alamosa 30'× 60' quadrangle is located in the central San Luis Basin of southern Colorado and is bisected by the Rio Grande. The Rio Grande has headwaters in the San Juan Mountains of Colorado and ultimately discharges into the Gulf of Mexico 3,000 kilometers (km) downstream. Alluvial floodplains and associated deposits of the Rio Grande and east-draining tributaries, La Jara Creek and ConejosGeologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado
The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by youngGeologic map of the Mount Sherman 7.5' quadrangle, Lake and Park Counties, Colorado
The Mount Sherman 7.5- minute quadrangle is located along the crest of the Mosquito Range in between Leadville and Fairplay, Colorado. There are eleven 13,000-foot peaks and one fourteener, Mount Sherman, within the quadrangle. General elevations range from 10,400–14,036 feet (3,200–4,278 meters). The western half of the quadrangle primarily consists of Proterozoic granitic rocks reverse faulted oGeologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado
Recent mapping and geochronologic studies for the eastern half of the Vail 1:100,000-scale quadrangle have significantly improved our understanding of (1) Paleoproterozoic history of the basement rocks of the Gore Range and Williams Fork Mountains (western margin of the Front Range), (2) the Late Paleozoic history of the Gore fault system, (3) Laramide contractional tectonism, including deformatioGeologic map of the Sand Creek Pass quadrangle, Larimer County, Colorado, and Albany County, Wyoming
New geologic mapping within the Sand Creek Pass 7.5 minute quadrangle defines geologic relationships within the northern Front Range of Colorado along the Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping; Eaton Reservoir 7.5 minute quadrangle to the east (2008), granite of the Rawah batholith to the soutGeologic map of the Fraser 7.5-minute quadrangle, Grand County, Colorado
The geologic map of the Fraser quadrangle, Grand County, Colo., portrays the geology along the western boundary of the Front Range and the eastern part of the Fraser basin near the towns of Fraser and Winter Park. The oldest rocks in the quadrangle include gneiss, schist, and plutonic rocks of Paleoproterozoic age that are intruded by younger plutonic rocks of Mesoproterozoic age. These basement rGeologic Map of the Estes Park 30' x 60' Quadrangle, North-Central Colorado
The rocks and landforms of the Estes Park 30 x 60 minute quadrangle display an exceptionally complete record of geologic history in the northern Front Range of Colorado. The Proterozoic basement rocks exposed in the core of the range preserve evidence of Paleoproterozoic marine sedimentation, volcanism, and regional soft-sediment deformation, followed by regional folding and gradational metamorphiGeologic Map of the Eaton Reservoir Quadrangle, Larimer County, Colorado and Albany County, Wyoming
New geologic mapping of the Eaton Reservoir 7.5' quadrangle defines geologic relationships in the northern Front Range along the Colorado/Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping (Tweto, 1979; Camp, 1979; Burch, 1983) and some minor site-specific studies (Carlson and Marsh, 1986; W. Braddock, unp - Publications
Below are publications associated with this project.
Filter Total Items: 17A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near TaAuthorsV. J. S. Grauch, Paul W. Bauer, Benjamin J. Drenth, Keith I. KelsonGeologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado
Deposits of the North Park Formation of late Oligocene and Miocene age are locally exposed at small, widely spaced outcrops along the margins of the roughly northwest-trending North Park syncline in the southern part of North Park, a large intermontane topographic basin in Jackson County in north-central Colorado. These outcrops suggest that rocks and sediments of the North Park Formation consistAuthorsRalph R. ShrobaMountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains
This report describes, in a nontechnical style, the geologic history and mining activity in the Blue River region of Colorado, which includes all of Summit County. The geologic story begins with the formation of ancient basement rocks, as old as about 1700 million years, and continues with the deposition of sedimentary rocks on a vast erosional surface beginning in the Cambrian Period (about 530 mAuthorsKarl S. Kellogg, Bruce Bryant, Ralph R. ShrobaAirborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado
In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field infAuthorsLyndsay B. Ball, Benjamin R. Bloss, Paul A. Bedrosian, V. J. S. Grauch, Bruce D. SmithSample descriptions and geophysical logs for cored well BP-3-USGS, Great Sand Dunes National Park and Preserve, Alamosa County, Colorado
The BP-3-USGS well was drilled at the southwestern corner of Great Sand Dunes National Park in the San Luis Valley, south-central Colorado, 68 feet (ft, 20.7 meters [m]) southwest of the National Park Service’s boundary-piezometer (BP) well 3. BP-3-USGS is located at latitude 37°43ʹ18.06ʺN. and longitude 105°43ʹ39.30ʺW., at an elevation of 7,549 ft (2,301 m). The well was drilled through poorly coAuthorsV. J. S. Grauch, Gary L. Skipp, Jonathan V. Thomas, Joshua K. Davis, Mary Ellen BensonPotassium-argon (argon-argon), structural fabrics
Definition: 40Ar/39Ar geochronology of structural fabrics: The application of 40Ar/39Ar methods to date development of structural fabrics in geologic samples. Introduction: Structural fabrics develop during rock deformation at variable pressures (P), temperatures (T), fluid compositions (X), and time (t). Structural fabrics are represented in rocks by features such as foliations and shear zonesAuthorsMichael A. CoscaNeotectonics and geomorphic evolution of the northwestern arm of the Yellowstone Tectonic Parabola: Controls on intra-cratonic extensional regimes, southwest Montana
The catastrophic Hebgen Lake earthquake of 18 August 1959 (MW 7.3) led many geoscientists to develop new methods to better understand active tectonics in extensional tectonic regimes that address seismic hazards. The Madison Range fault system and adjacent Hebgen Lake–Red Canyon fault system provide an intermountain active tectonic analog for regional analyses of extensional crustal deformation. TAuthorsChester A. Ruleman, Mort Larsen, Michael C. Stickney40Ar/39Ar Geochronology, Isotope Geochemistry (Sr, Nd, Pb), and petrology of alkaline lavas near Yampa, Colorado: migration of alkaline volcanism and evolution of the northern Rio Grande rift
Volcanic rocks near Yampa, Colorado (USA), represent one of several small late Miocene to Quaternary alkaline volcanic fields along the northeast margin of the Colorado Plateau. Basanite, trachybasalt, and basalt collected from six sites within the Yampa volcanic field were investigated to assess correlations with late Cenozoic extension and Rio Grande rifting. In this paper we report major and trAuthorsMichael A. Cosca, Ren A. Thompson, John P. Lee, Kenzie J. Turner, Leonid A. Neymark, Wayne R. PremoAdvancements in understanding the aeromagnetic expressions of basin-margin faults—An example from San Luis Basin, Colorado
Advancements in aeromagnetic acquisition technology over the past few decades have led to greater resolution of shallow geologic sources with low magnetization, such as intrasedimentary faults and paleochannels. Detection and mapping of intrasedimentary faults in particular can be important for understanding the overall structural setting of an area, even if exploration targets are much deeper. AAuthorsV. J. Grauch, Paul A. Bedrosian, Benjamin J. DrenthOblique transfer of extensional strain between basins of the middle Rio Grande rift, New Mexico: Fault kinematic and paleostress constraints
The structural geometry of transfer and accommodation zones that relay strain between extensional domains in rifted crust has been addressed in many studies over the past 30 years. However, details of the kinematics of deformation and related stress changes within these zones have received relatively little attention. In this study we conduct the first-ever systematic, multi-basin fault-slip measuAuthorsScott A. Minor, Mark R. Hudson, Jonathan S. Caine, Ren A. ThompsonIdentifying buried segments of active faults in the northern Rio Grande Rift using aeromagnetic, LiDAR,and gravity data, south-central Colorado, USA
Combined interpretation of aeromagnetic and LiDAR data builds on the strength of the aeromagnetic method to locate normal faults with significant offset under cover and the strength of LiDAR interpretation to identify the age and sense of motion of faults. Each data set helps resolve ambiguities in interpreting the other. In addition, gravity data can be used to infer the sense of motion for totalAuthorsV. J. S. Grauch, Chester A. RulemanDigital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado
This report contains digital data and supporting explanatory files describing data types, data formats, and survey procedures for a high-resolution airborne gravity gradient (AGG) survey at Great Sand Dunes National Park, Alamosa and Saguache Counties, south-central Colorado. In the San Luis Valley, the Great Sand Dunes survey covers a large part of Great Sand Dunes National Park and Preserve. TheAuthorsB. J. Drenth, J.D. Abraham, V. J. S. Grauch, V.F. Labson, G. Hodges