Park Service geology report on Tumacacori

The National Park Service has released a Geologic Resources Inventory (GRI) report for Tumacacori National Historical Park (TUMA) in Arizona. The report is a companion document to the previously released digital geologic map data and aids in its use for resource management. [right, cross section Geologic structural cross-section showing the Mount Benedict horst block and normal faults that separate the uplift from the Santa Cruz Valley to the west and the Santa Cruz River and Nogales International Airport to the east. This cross section is located approximately 500 m (1,500 ft) southwest of the Guevavi Unit. Normal faulting in the Basin and Range Province juxtaposed older Jurassic igneous rocks in the Mount Benedict horst (map units Jm and Jb) against younger Tertiary (Paleogene and Neogene) rocks in the basin (e.g., map unit Tnl). Graphic by Trista Thornberry-Ehrlich (Colorado State University). Section and caption from NPS]

The GRI report is written for resource managers to assist in resource management and science-based decision making, but may also be useful for interpretation. The report discusses potential geologic issues facing resource managers at the park, distinctive geologic features and processes present within the park, and the geologic history leading to the park’s present landscape. A map unit properties table summarizes the main features, characteristics, and potential management issues for all of the rock units on the geologic map.

Origin of the Colorado River system

Abstracts from the workshop on the Origin and evolution of the Colorado River system, have been published by the USGS. [right, credit Grand Canyon NPS]

A 2010 Colorado River symposium, held in Flagstaff, Arizona, involved 70 participants who engaged in intense debate about the origin and evolution of the Colorado River system. This symposium, built upon two previous decadal scientific meetings, focused on forging scientific consensus, where possible, while articulating continued controversies regarding the Cenozoic evolution of the Colorado River System and the landscapes of the Colorado Plateau-Rocky Mountain region that it drains. New developments involved hypotheses that Neogene mantle flow is driving plateau tilting and differential uplift and new and controversial hypotheses for the pre-6 Ma presence and evolution of ancestral rivers that may be important in the history and birth of the present Colorado River. There is a consensus that plateau tilt and uplift models must be tested with multidisciplinary studies involving differential incision studies and additional geochronology and thermochronology to determine the relative importance of tectonic and geomorphic forces that shape the spectacular landscapes of the Colorado Plateau, Arizona and region. In addition to the scientific goals, the meeting participants emphasized the iconic status of Grand Canyon for geosciences and the importance of good communication between the research community, the geoscience education/interpretation community, the public, and the media. Building on a century-long tradition, this region still provides a globally important natural laboratory for studies of the interactions of erosion and tectonism in shaping the landscape of elevated plateaus.

CRevolution 2—Origin and evolution of the Colorado River system, workshop abstracts, USGS OFR 2011-1210, http://pubs.er.usgs.gov/publication/ofr20111210

Active Metal and Industrial Mineral Underground Mines in the United States, 2007-2009

The USGS released 3 annual reports on Active Metal and Industrial Mineral Underground Mines in the United States, for the years 2007, 2008, and 2009. No mines are reported in Arizona.

According to the latest report, "Total domestic mining and waste removal for nonfuel mineral materials production at underground operations was 138 million metric tons (Mt) in 2009. Crude ore mined at these underground operations was 136 Mt. The balance was waste removed, including ore and waste from development. Total underground mining for industrial minerals amounted to 123 Mt, nearly all of which was crude ore. Underground mining for metal ores and waste removal amounted to 15 Mt, of which 90% was crude ore."

Emergency declaration for Schultz post-fire flood area

Gov. Jan Brewer signed a Declaration of Emergency on Friday, in support of Coconino County response, recovery and mitigation efforts to protect property and infrastructure in the Schultz Flood area, in the Flagstaff area.

The declaration was signed in response to a heavy monsoon rainstorm that dropped more than 1 inch of rain within 15 minutes in the Timberline, Hutchison Acres and Wupatki Trails neighborhoods on Sept. 13, 2011, causing significant street flooding and damage. Flood waters also undermined the utility of previously placed protective structures. Major construction is required to restore them to their pre-disaster condition.

These neighborhoods are among the areas where monsoon season flooding has been most prevalent since the Schultz Fire of 2010. [right, home owners efforts to divert flood waters, Aug, 2010. My photo]

Gov. Brewer is authorized under state statute to declare a state of emergency and release an initial $200,000 from the Governor’s Emergency Fund. This money will be used to pay for emergency response costs and to repair public infrastructure, such as the roads that suffered damage as a result of this event. These funds are not available to repair individual homes.

Coconino County continues to supply sandbags to property owners in high flood-risk areas. Residents with questions can call the Schultz Flood hotline at 877-679-8390.

[taken from the AZ Div. of Emergency Mgmt, Emergency Information Network]

Tiny quake in NW Arizona

There was a small earthquake last Thursday on what appears to be the southern extent of the Hurricane fault in northwestern Arizona.

[right, star marks epicenter, amidst historical earthquakes in the region. Credit, USGS]