Tonto National Monument: geologic resources inventory report
KellerLynn K. 2020. Tonto National Monument: geologic resources inventory report. Natural Resource Report. NPS/NRSS/GRD/NRR—2020/2212. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/nrr-2283508
The Geologic Resources Inventory (GRI) provides geologic map data and pertinent geologic information to support resource management and science-informed decision making in more than 270 natural resource parks throughout the National Park System. The GRI is one of 12 inventories funded by the National Park Service (NPS) Inventory and Monitoring Program. The Geologic Resources Division of the NPS Natural Resource Stewardship and Science Directorate administers the GRI. This report synthesizes discussions from a scoping meeting held in 2006 and a follow-up conference call in 2019. Appendix A provides lists of participants. Chapters of this report discuss the monument’s geologic setting and significance, drawing connections between geologic and cultural resources; highlight distinctive geologic features and processes of interest for the monument, including geologic events leading to the monument’s present-day landscape; discuss geologic issues facing resource managers; and provide information about the previously completed GRI map data. Two posters illustrate these data. Tonto National Monument (referred to as the “monument” throughout this report) is in Gila County, Arizona. The nearest “census designated place” is Roosevelt, Arizona. The monument is within a transition zone between the Basin and Range and Colorado Plateau physiographic provinces. Arizona’s transition zone has characteristics of both the Basin and Range and Colorado Plateau, though the monument’s setting favors the Basin and Range. On 19 December 1907, the monument became one of the nation’s first national monuments designated under the Antiquities Act of 1906. Originally under stewardship of the USDA Forest Service, management of the monument transferred to the National Park Service in 1937. On 15 October 1966, 21 April 1989, and 9 September 2010, the National Register of Historic Places listed the Tonto National Monument Archeological District, Lower Ruins and Upper Ruins, and Tonto National Monument Visitor Center, respectively. The geology of the monument played an essential role in the lives of the ancestral people who inhabited the area from around 1150 CE to 1450 CE. In the 1930s, archeologists working in the valley of the Salt River (“Rio Salado”) applied the name “Salado” to this culture of people and associated artifacts. Geologic resources provided the raw materials from which people of the Salado culture shaped tools for everyday living and built structures. In addition, geologic processes created caves in which the Salado people found shelter and built dwellings. Moreover, groundwater springs served as a source of water, and major surface-water streams were vital to prehistoric farming. The most distinguishing features at the monument are the Upper and Lower Cliff Dwellings (also referred to as the “Ruins”). Geologic processes created the caves—referred to as “shelter caves” or “alcoves”—that contain the cliff dwellings. Significantly, this inventory resulted in an important correction to the previously interpreted geologic location of the cliff dwellings. Raup (1959) had interpreted that both the Upper and Lower Cliff Dwellings occurred in the Dripping Spring Quartzite; park literature perpetuated that interpretation. Geologic mapping completed by the Arizona Geological Survey and compiled in the GRI GIS data for the monument, however, revealed that the Upper Cliff Dwelling occurs in the Dripping Spring Quartzite (geologic map unit Ydsu) whereas the Lower Cliff Dwelling occurs in the Mescal Limestone (Ymd). The “Geologic Features and Processes” chapter discusses these and other features of significance for the monument’s geologic story.
- Type
- Published Report
- Authors
- KellerLynn, Katie
- Date of Issue
- 2020-12
- Publisher
- National Park Service
- DOI
- 10.36967/nrr-2283508
- Units
- GRD , GRI , IMR , NRSS , SODN , TONT
- Keywords
- Active Faults and Earthquakes, Aircraft-Induced Vibration, Arizona, Basin Fill, Cave Resource Management, Caves and Cliff Dwellings, Climate Change, Conglomerates, Fire and Slope Movements, Flash Floods, Geologic Features, Geologic History, Geologic Processes, Geologic Resource Management Issues, Geologic Resources Division, Geologic Resources Inventory, Geothermal Resources, GRD, GRI, Holocene Deposits, Lithic Resources, Map Units, National Park Service, NPS, Paleontological Resources, Pleistocene Deposits, Proterozoic Rocks, Resource Management, Rockfall Hazard, Seismicity, Springs and Groundwater Resources, TONT, Tonto National Monument, Unconformities
- Subjects
- Ecological Framework: Geology and Soils | Geomorphology | Windblown Features and Processes , Ecological Framework: Geology and Soils | Geomorphology | Hillslope Features and Processes , Ecological Framework: Geology and Soils | Geomorphology | Stream/River Channel Characteristics , Ecological Framework: Geology and Soils | Subsurface Geologic Processes | Geothermal Features and Processes , Ecological Framework: Geology and Soils | Subsurface Geologic Processes | Cave/Karst Features and Processes , Ecological Framework: Geology and Soils | Subsurface Geologic Processes | Seismic Activity , Ecological Framework: Geology and Soils | Soil Quality | Soil Function and Dynamics , Ecological Framework: Geology and Soils | Paleontology | Paleontology