Blue Ridge Parkway: Geologic resources inventory report
Thornberry-Ehrlich TL. 2020. Blue Ridge Parkway: Geologic resources inventory report. Natural Resource Report. NPS/NRSS/GRD/NRR—2020/2194. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/nrr-2279838
This report synthesizes discussions from a scoping meeting held in 2000 and a follow-up conference call in 2017 (see Appendix A). Chapters of this report highlight the geologic setting, describe distinctive geologic features and processes within Blue Ridge Parkway, discuss geologic issues facing resource managers, summarize the geologic history leading to the present-day landscape, and provide information about the previously completed GRI map data. As the longest road to be designated as a single park unit in the United States, Blue Ridge Parkway protects a755 km (469 mi) ribbon of mountain landscapes including high passes, lush vegetation, waterfalls, water and wind gaps, forests, and upland meadows. With 15 million visitors in 2019, the parkway was second only to Golden Gate National Recreation Area (California) for highest visitation in the National Park System. The parkway passes through 29 counties of Virginia and North Carolina and is an engineering marvel that includes 26 tunnels and 168 bridges designed in harmony with the local rock, including the Linn Cove Viaduct at milepost 304. The viaduct was constructed specially to avoid degrading the vulnerable ecosystem at Grandfather Mountain; the mountain itself is among the more significant geologic features of the southern Appalachians. The geologic story of the parkway spans more than one billion years. The rocks exposed along the Blue Ridge Parkway are the core of an ancient mountain chain. The Appalachian Mountains are the remnants of a chain of mountains that may have rivaled the Himalayas when they formed more than 250 million years ago. The long geologic history, recorded in the rocks along the parkway, involves an early supercontinent, the opening and closing of an ancient ocean to form another supercontinent, followed by the rifting that opened the Atlantic Ocean. The rocks are broadly divisible into six groups: (1) Mesoproterozoic basement complex (more than 1 billion years old), (2) Neoproterozoic metasedimentary and metaigneous complexes (more than 541 million years old), (3) Neoproterozoic to Cambrian sedimentary and metamorphic rocks spanning the time across the Proterozoic into the Paleozoic (between 1 billion and 488 million years old), (4) Paleozoic sedimentary and mylonitic rocks, (5) Jurassic igneous rocks (more than 145 million years old), and (6) Cenozoic surficial deposits that are still forming on the landscape today. This report is supported by three GRI-compiled maps of the geology of Blue Ridge Parkway: Carter et al. (2016), Merschat et al. (2008a), and Merschat et al. (2008b). The maps were developed by two groups of geologists: US Geological Survey (USGS) geologists developed the maps for the Virginia portion of the parkway; the GRI team compiled these maps into the blrn_geology.mxd data set. The North Carolina Geological Survey (NCGS) geologists developed the maps for the North Carolina portion of the parkway; the GRI team compiled these maps into the blrs_ geology.mxd data set. The Virginia portion includes data in a broader buffer around the parkway boundary than the North Carolina portion. Additionally, surficial geologic mapping and geologic hazards mapping are part of the North Carolina GRI GIS data (brhz_ geohazards.mxd). Map unit descriptions, reports, and hundreds of annotated photographs accompany the data. Many of these photographs are used in this report to help illustrate geologic features. The photographs correspond to geologic observation localities in the GRI GIS data.
- Type
- Published Report
- Authors
- Thornberry-Ehrlich, Trista
- Date of Issue
- 2020-11
- Publisher
- National Park Service
- DOI
- 10.36967/nrr-2279838
- Units
- APHN , BLRI , GRD , GRI , NRSS , SECN , SER
- Keywords
- Abandoned Mineral Lands, and Great Balsam Mountains, and Metamorphic Rocks, Bedrock Exposures: Sedimentary, Black, BLRI, Blue Ridge, Blue Ridge Parkway, Blue Ridge Parkway Segments, Disturbed Lands Restoration and Structural Integrity of the Parkway, Earth Surface Processes: Surficial Units, Faults and Folds, Gaps, Geologic Features, Geologic Hazards, Geologic History, Geologic Processes, Geologic Resource Management, Geologic Resource Management Issues, Geologic Resources Division, Geologic Resources Inventory, GRD, Great Craggy, GRI, Igneous, National Park Service, North Carolina, NPS, Paleontological Resources, Pisgah, Resource Management, Virginia, Wetlands
- 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 | Seismic Activity , Ecological Framework: Geology and Soils | Soil Quality | Soil Function and Dynamics , Ecological Framework: Geology and Soils | Paleontology | Paleontology