We just delivered geologic map data for four 7.5’ quadrangles to the US Geological Survey as part of our 2017 STATEMAP work – see the list below. Before releasing the map and GIS database publically, the authors will make any necessary revisions, polish the map appearance and the legend for consistency with AZGS standards. Delivery of draft maps to the USGS program managers is required at the end of each contract period; grant funding for the next STATEMAP projects depends on this.
All participating state geological surveys submit draft maps, then clean and polish them before releasing them to the public. For the AZGS, it has typically required 6 to 15 months to finalize and release the maps, as this work is done while the geologists are also working on the next mapping projects. Meanwhile, the geologists are gearing up for the next field season, which begins later this fall or early winter.
Since 1992, AZGS has participated in the U.S. Geological Survey’s STATEMAP. To date, AZGS has received ~ $4M in federal funds, matched $ for dollar by state funds, for a total of $8 M. AZGS geologists meet annually with Arizona Geologic Mapping Advisory Committee to identify high priority areas for new mapping. Our map advisory team plays a crucial role in helping select mapping that are particularly relevant to resolving challenging geologic, and often, socio-geologic problems.
This past year, our mapping focused on quadrangles in SW and SE Arizona – see the map figure. The Dragoon area was chosen because it hosts porphyry copper deposits with substantial potential economic value. The Blythe and North Trigo Peaks quadrangles contain ancient river deposits that help us understand origin and evolution of the Colorado River, and North Trigo Peaks contains diverse and complex bedrock geology that sheds new light on Mesozoic and Cenozoic tectonism in the region.
The ~½ of the Blythe quadrangle in California covers much of the late Holocene floodplain of the Colorado River. The surficial deposits there have been completely altered by agricultural and urban activity, but our collaborators with the USGS office in Flagstaff (Debra Block and Kyle House) used historical aerial photographs and early topographic maps to make a detailed geologic map of this area.
The Gila River Valley near Safford contains the young river floodplain and multiple levels of terraces recording former river levels, and many great exposures of the basin deposits that are providing insights into how the river developed. Image: Ann Youberg examining basin-fill sediments exposed along near Ft. Thomas.
2017 Geologic Mapping · Geologic Map of the Blythe 7 ½’ quadrangle, La Paz County, AZ and Riverside County, CA. AZGS DGM-124 – Brian Gootee, Debra Block (USGS), Philip Pearthree, Kyle House (USGS)
· Geologic Map of the North Trigo Peaks 7 ½’ quadrangle, La Paz County, AZ – AZGS DGM-123 – Charles Ferguson, Philip Pearthree, Brian Gootee, Bradford Johnson
· Geologic Map of the Ft Thomas area, Graham County, AZ – ASGS DGM-126 – Ann Youberg and Joseph Cook
· Geologic Map of the Dragoon 7 ½’ quadrangle, Cochise, County, AZ – AZGS DGM-125 – Bradford Johnson, Joseph Cook, Charles Ferguson
2016 Geologic Mapping – to be released later this fall Meanwhile, later this year we’ll release static digital versions of the geologic maps and GIS data in a number of useful formats for the following map quadrangles.
· Pima-Markham Creek – SE Arizona
· Oatman – NW Arizona
· Moon Mountain – W Arizona
· Middle Camp Mountain – W Arizona
2018 Geologic Mapping - Planning underway
We will be meeting with our Geologic Mapping Advisory Committee in the next few weeks to determine priorities for the next mapping cycle, which will begin in September 2018. The proposal for this mapping is due to the USGS in mid-November. There are many interesting and important areas yet to map in Arizona!
Contributors: M. Conway, P. Pearthree, J. Cook
The Sonoran Desert of Arizona and northern Sonora, Mexico, hosts some
of the wildest and most intriguing geology in the Southwest. In March
1990, the Geological Society of America’s Cordilleran Section met in
Tucson, Arizona, to review fresh geologic research and to visit a broad
suite of geologic settings.
