GEOLOGIC MAPPING SUBCOMMITTEE
NEVADA STATE MAPPING ADVISORY COMMITTEE (SMAC)
August 20, 2001, 1:00 PM Scrugham Engineering/Mines Building, Room 401 Nevada Bureau of Mines and Geology (NBMG) University of Nevada, Reno Reno, Nevada (775) 784-6691
Jon Price and Chris Henry reviewed the previously established priorities for new geologic quadrangle mapping. They discussed the various priority layers and how they were developed and combined into the present high, higher, and highest categories. Priority areas in Southern Nevada were primarily driven by growth, industrial minerals, and water issues. Growth and industrial minerals were identified as important issues in the Reno area. Issues associated with the priorities in the Humboldt basin include environmental concerns regarding large scale mine de-watering and flow pattern impacts on the Humboldt River system and the study of the linkage between magmatisim and economic ore deposits in Northeastern Nevada.
Jon Price opened the floor to discussion of these priorities and to identify any adjustments that may be needed. Shawn Gooch, from the City of Sparks, stated that we should maintain the emphasis on urban area mapping. As Sparks continues to grow outward developers and city planners continue to identify important geologic features that are either not on or are mislocated on current urban area maps. Features of importance would be faults, liquefaction potential, areas of swelling clays, and detailed Truckee River flood plain information.
Elizabeth Jones Crafford, from GeoLogic, stated that ground water and urbanization issues are important but mapping must not ignore areas of scientific significance.
Peter Vikre, from the USGS Geologic Division, stated that the USGS has an ongoing interest in the study of overthrusting in Nevada and an ongoing project in the Humboldt Basin. John Sutter with the USGS should be contacted about USGS geologic mapping activity in Nevada. Current FEDMAP geologic mapping projects proposed in Nevada are around Death Valley and the Test Site. An upcoming USGS project, with Alan Wallace as one of the leads, on diatomite may have a geologic mapping component.
Kyle House, with NBMG, reviewed his planned proposal for the upcoming STATEMAP program. It includes mapping the surficial geology for approximately 9 Southern Nevada quads over a 3-year time span, approximately 3 quads per year. This mapping is in an area soon to be developed as a major airport and urban center in Clark County, Nevada. The project is centered on the Roach quadrangle and is along the I15 corridor, which was identified during last year's Geologic Mapping Subcommittee meeting as a high priority area for new geologic mapping. Clark County Flood Control District will be a major cooperator for this project and is excited about obtaining detailed data of this caliber before development has commenced in the area.
Craig dePolo, with NBMG, reviewed his planned work in Pahrump Valley. He intends to submit a proposal to map 2 one-quarter quad sections along the Pahrump Valley fault zone, the northeast quarter of the Nopah Peak quad and the northeast quarter of the Stewart Valley quad. Mapping in this area will help to define flood zones and better understand the Pahrump Valley fault zone.
John Bell, with NBMG, will propose mapping the surficial geology of the west half of the Nixon quad. This mapping will better define the fault relationships in the area and also lead to a better understanding of the environment associated with the deposition of Lake Lahontan deposits in this area.
Allan Ramelli, with NBMG, will propose mapping the Russells Quadrangle which is directly north of the Battle Mountain quad. Mapping in this area will lead to a better understanding of how major faulting events may have altered the course of the Humboldt River.
Chris Henry, with NBMG, reviewed the STATEMAP projects he is currently working on, Dogskin Mountain, Tule Peak, and Sutcliffe. He will not be proposing any new projects this year.
Ron Hess, with NBMG, listed the NBMG geologic maps that are being proposed for full GIS digital conversion as part of the upcoming STATEMAP proposal: Battle Mountain, Bullfrog Hills, Eugene Mountains, Fairview Range, Frenchman Mountain, Grassy Mountain, Lamoille, Lime Mountain, Mount Davis, Stony Point, and Toe Jam Mountain. He is also looking at the possibility of adding the USGS Walker Lake 1 by 2 degree geologic map (MF 1382-A) to the proposal for digital conversion. John Bell suggested including the USGS Walker Lake 1 by 2 degree surficial geologic map (MF 1382-C) since it is part of the same set. A digital version of these maps would be a significant improvement in the quality of 1:250,000 scale digital data over this area. Currently, the only published 1:250,000 scale geologic mapping that has been converted to digital format in this area is based on mapping from the 1961 Geology and Mineral Deposits of Mineral County Bulletin. It was suggested that the USGS may already have these maps in some digital format. If the USGS does not have it and is not currently working on a digital conversion of the Walker Lake 1 by 2 degree geologic maps then Hess will add both of them to the proposal. It was also announced that Anglo Gold, Inc., has donated approximately 130 USGS MF, GQ, and I series maps, in a scanned georeferenced, digital format, to the DeLaMare Library Keck Web site (https://keck-nbmg.opendata.arcgis.com// ) where they can be downloaded for free.
Elizabeth Jones Crafford asked about the status of updating the State geologic map. Peter Vikre responded that Steve Luddington with the USGS is working on updating some information that would be needed for an update to the State geologic map. Jon Price responded by acknowledging that the idea received enthusiastic support at GSN 2000 but workload and the need for better, larger scale mapping, in various areas of the State have overshadowed the project at NBMG and it has not moved forward. The NBMG leads for the State geologic map update are Chris Henry, Larry Garside, and Jim Faulds. Chris Henry stated that there are insufficient time and resources available, at present, to continue with both the quadrangle mapping program and a revision of the State geologic map at the same time.
Shawn Gooch asked about how quads were selected at NBMG for proposal to the STATEMAP program. Chris Henry and Jon Price responded that it is a combination of staff interest, available opportunities in obtaining additional resources such as cost/work share with another agency, what priority area the map falls into, and the significance of the area to the understanding of geologic problems of importance to the surrounding area.
Jon Price asked for any additional comments or concerns with the slate of projects currently being proposed to the STATEMAP program.
Elizabeth Jones Crafford said it looked fine and that she would also send in the names of several quads, for possible prioritization in upcoming STATEMAP proposals, which she believes are in an area that warrant detailed mapping because of potential scientific and resource benefits that would be associated with a better understanding of the geology in these areas.
Shawn Gooch agreed that the current projects looked appropriate and requested information on plans to address problems associated with older urban area geologic maps. Chris Henry responded that there are problems with some older maps but no clear idea on how to best remedy these problems has been developed. The possibilities include full revision, partial revisions, digital updates, explanatory warnings and disclaimers on existing maps, etc. Ron Hess explained that on maps that had suspected problems it was decided to not do a full digital conversion and only scan and georeference the scanned image.
Jon Price thanked everybody for attending and adjourned the meeting at 3:10 PM.
|Jon Price||Nevada Bureau of Mines and Geology, committee chairman|
|Ron Hess||Nevada Bureau of Mines and Geology|
|Peter Vikre||U.S. Geologic Survey, Geologic Division|
|Gary Johnson||Nevada Bureau of Mines and Geology|
|Robert Chaney||Nevada Bureau of Mines and Geology|
|Alan Ramelli||Nevada Bureau of Mines and Geology|
|Kyle House||Nevada Bureau of Mines and Geology|
|Chris Henry||Nevada Bureau of Mines and Geology|
|Craig dePolo||Nevada Bureau of Mines and Geology|
|Shawn Gooch||City of Sparks|
|John Bell||Nevada Bureau of Mines and Geology|
In 1992, with passage of the National Geologic Mapping Act and formation of the National Cooperative Geologic Mapping Program, SMAC established a Geologic Mapping Subcommittee. This committee, which meets when necessary, advises the Nevada Bureau of Mines and Geology on priorities for geologic mapping. Members of the Advisory Committee for the Nevada Bureau of Mines and Geology are encouraged to participate in the Geologic Mapping Subcommittee, whose membership is open to anyone interested in geologic mapping in Nevada. In recent years numerous maps have been produced from the STATEMAP and EDMAP components of the National Cooperative Geologic Mapping Program, those parts of the program that make federal dollars available on a competitive basis for matching from state geological surveys and universities. The Nevada Bureau of Mines and Geology, which is the state geological survey and a research and public service unit of the University and Community College System of Nevada, has successfully competed in this program since its inception. The Geoscience Department at UNLV has participated in the EDMAP component.