Arizona geology

              Arizona Geological Survey
ARIZONA (formerly fieldnotesi GEOLOGY
I
Vol. 18, No. 3 Investigations Service Information Fall 1988
4
Arizona Geological Survey: A New State Agency
by Lamj D. Fellows
State Geologist
Arizona Geological Survey
The Arizona Geological Survey
(AZGS) became an independent State
agency July 1, 1988 in accordance with
Senate Bill 1102, which was enacted in
1987. The administrative head of the
AZGS, the State Geologist, is appointed
by the Governor. The purpose of the
AZGS - to assist the wise use of lands
and mineral resources in Arizona by pro-viding
scientific and investigative re-search
and information - was essentially
unchanged.
To facilitate the conduct of research
and investi~ations. the legislature sveci-fied
in ~ ~ l ' i 0th2at the A ~ G Sof fice's be
located in proximity to the University of
Arizona in Tucson and that AZGS staff
"shall have reasonable access to the data
and other resources of the University of
Arizona or any other State university in
Arizona." Many AZGS projects are com-pleted
with the assistance of faculty
and graduate students. Thirtv-nine of
the 64u items ~ublishedb v the A ~ G Sdu r-ing
Fiscal ~e ' a r1 987-88 &ere coauthored
I by University of Arizona faculty or
Gaduate students. Sixteen of tge 64
were coauthored by faculty or graduate
students from other universities.
The ancestral AZGS began in 1881,
when the Office of the Territorial Geol-ogist
was established by the Territorial
Legislature. The primary duties were to
collect and provide information about
t mineral resources. In 1893 the University
of Arizona established a testing labora-tory,
known informally as the "Bureau of
i Mines." From then until statehood in
1912, Territorial Geologists were also
affiliated with the "Bureau of Mines" and
the university. A 1915 statute formally
established the Arizona Bureau of Mines
ea s a State agency administered by the University of Arizona, continuing, essen-tially
unchanged, the functions of the
"Bureau of Mines" and the Territorial
Geologist. Data collection and research
activities continued to be concentrated
on mineral resources. Sixty-two years
later, in 1977, the Bureau's enabling
legislation was modernized and its name
was changed to the Arizona Bureau of
Geology and Mineral Technology. It
continued to be administered as a divi-sion
of the University of Arizona. The
Bureau was charged with investigating
geologic hazards and limitations, as well
as the geologic framework and mineral
resources of Arizona, in anticipation of
population growth and increased compe-tition
for and conflict over land, miner-al
resources, and water.
Similar patterns of development and
growth have taken place in other State
geological surveys; most other States and
surveys, however, have been in existence
longer than Arizona and the AZGS.
Twenty-nine State geological surveys
were founded before 1860; 36 were es-tablished
before the Office of the Terri-torial
Geologist in Arizona Territory.
Forty-nine States liow have a geological
survey. Thirty-six of the surveys are
independent agencies or part of an
executive-branch agency; 13 are part of
a university. Twenty-six State geologi-cal
surveys are on or adjacent to a
university campus.
The name of this publication, the
quarterly newsletter of the AZGS, has
been changed from Fieldnotes to Arizona
Geology, coincident with the statutory
change, to reflect its contents more
accurately. Fieldnotes from the Arizona
Bureau of Mines was first published in
March 1971. The Fall-Winter issue of
1977 was the first issue published by the
Arizona Bureau of Geology and Mineral
Technology. This issue of Arizona Geology
was typeset in-house on a laser printer.
All subsequent issues will be typeset ac-cordingly.
The AZGS logo also differs from that
of the former Bureau. As illustrated in
the masthead, it is a miniature geologic
map of Arizona that shows the Colorado
Plateau, Transition Zone, and Basin and
Range physiographic provinces.
Although the AZGS is now indepen-dent
of the University of Arizona, it
maintains close ties with the Department I,
of Geosciences as well as other univer-sity
departments. AZGS staff members I hope to strengthen these working rela-tionships
and develop closer cooperation
with the geology departments at Arizona
State University and Northern Arizona
University. Other AZGS plans include
expanding its computerized database,
preparing bibliographies, and providing
geologic data to agencies and individuals
concerned with the special problems in
land and resource management caused
by rapid population growth.
The AZGS offices are still located at
845 N. Park Ave. in Tucson. Office hours
are from 8:00 a.m. to 5:00 p.m. Monday
through Friday, except for a brief clo-sure
from 12:OO p.m. to 1:00 p.m. on
Tuesdays. AZGS staff are present to
assist those who use the library, buy
publications, or consult with geologists
during these hours.
A New Geologic Map of Arizona
by Stephen J. Reynolds
Arizona Geological Survey
The Arizona Geological Survey
(AZGS) has released a new 1:1,000,000-
scale Geologic Map of Arizona (Figure
1). This map supersedes the 1:500,000-
scale State geologic map published in
1969, which is out of print and mostly
out of date because of more recent geo-logic
studies. The new Geologic Map of
Arizona incorporates numerous advances
in the understanding of the geology of
the State and bears little resemblance to
its predecessor, either in content or in
style of presentation. Although the new
map is physically smaller than the 1969
map, it contains more information and is
more detailed for many parts of the
State.
The most obvious difference between
the new and old State maps is the
choice of colors for map units. Most
Quaternary deposits are now shown in
shades of gray so that bedrock areas are
not lost in a sea of yellow, as in the
previous map. To emphasize their simi-larities,
related map units are shown by
shades of a single-color, rather than by
different colors. For example, all volca-nic,
granitic, and sedimentary rocks
formed during an important episode of
mid-Tertiary tectonism (mountain build-ing)
are shown in shades of orange. The
new map also differs from the previous
one in that it is printed on a synthetic
water-resistant paper that should be
more durable in wind and rain.
The most important changes, however,
are in content. Although the 1969 map
represented a major step forward and
was as accurate as possible for its time,
the new map contains thousands of sig-nificant
improvements based on more
detailed geologic mapping and conceptu-al
breakthroughs. Although most changes
in the map are in the Basin and Range
Province and Transition Zone, where
compilers of the 1969 version were
forced to rely on reconnaissance map-ping,
numerous changes are also evident
in the Colorado Plateau Province. Some
of the most important geologic changes
are listed below.
(1) Quaternary and upper Tertiary
sedimentary deposits are subdivided into
four units, rather than two, on the basis
of age and geologic setting. For exam-ple,
recent alluvium within large river
channels and flood plains is shown sepa-rately
from older deposits further from
the rivers to highlight areas that may
experience flooding.
gently'dipping normal faults) thar were
not recognized or were identified as
thrust faults on the previous map are
also shown on the new map, as are
areas where rocks beneath the faults
were affected by mylonitization (high-temperature
shearing).
(3) Volcanic rocks erupted since 15
million years (m.y.) ago are subdivided
into five map units on the basis of rock
type and new radiometric age determina-tions.
For example, the map shows areas
where volcanic rocks erupted since 4
m.y. ago are present because these are
the most likely sites of future volcanic
eruptions.
(4) Because of numerous new radio-metric
age determinations, middle Ter-tiary
volcanic rocks are more widespread
on the new map than on. the 1969 map,
where they were depicted as Cretaceous,
Tertiary, or Quaternary in age.
(5) The ages of granitic rocks are
better known now than in 1969 and are
more correctly reflected on the new
map. This is especially important in min-eral
exploration because certain types of
mineral deposits are commonly associ-ated
with granites of a specific age.
(6) The geology of west-central,
southwestern, and south-central Arizona
appears very different on the new map
than on the 1969 map. Rocks depicted
as Mesozoic schist on the old map are
now recognized as mostly Jurassic vol-canic
and sedimentary rocks. Rocks
shown on the old map as Cretaceous
volcanic rocks and Quaternary to late
Tertiary basalt are now known to be
middle Tertiary in age. The new State
map also shows newly recognized Paleo- 0
zoic outcrops, Cretaceous thrust faults,
(continued on page 4)
2 Arizona Geology, vol. 18, no. 3, Fall 1988
Geologic Maps and Indexes
Published by the Arizona Geological Survey
These publications were compiled by
and may be purchased from the Arizona
Geological Survey (AZGS). For price
information, contact the AZGS offices at
845 N. Park Ave., Tucson, AZ 85719;
tel: (602) 621-7906. The publication
series are abbreviated as follows: B =
Bulletin; FS = Folio Series; M = Map;
OFR = Open-File Report.
Maps
B 195-Geology of the South Mountains,
Central Arizona, by S.J. Reynolds,
1985,61 p., scale 1:24,000.
FS 1-Environmental Geology of the
McDowell Mountains Area, Maricopa
County, Arizona, by G.E. Christenson,
D.G. Welsch, and T.L. Pe'we', 1978,
scale 1:24,000.
FS 2-Environmental Geology of the
Tempe Quadrangle, Maficopa County,
Arizona, by T.L. Pewe, C.S. Wellen-dorf,
and J.T. Bales, 1986, scale
1:24,000.
M 19-Map of Outcrops of Laramide
a (Cretaceous-Tertiary) Rocks in Arizo- na and Adjacent Regions [includes
explanatory pamphlet], by Stanley B.
Keith, 1984, scale 1:1,000,000.
M 20-Map of Mid-Tertiary Volcanic,
Plutonic, and Sedimentary Rock Out-crops
in Arizona, by R.B. Scarbor-ough,
1986, scale 1:1,000,000.
M 21-Map of Post-15-m.y. Volcanic
Outcrops in Arizona, by R.B. Scarbor-ough,
1985, scale 1:1,000,000.
M 22-Map of Late Pliocene-Quaternary
(Post-4-m.y.1 Faults, Folds, and Vol-canic
Outcrops in Arizona, by R.B.
Scarborough, C.M. Menges, and P.A.
Pearthree, 1986, scale 1:1,000,000.
OFR 81-22-Preliminary Detailed Geolog-ic
Map and Cross Sections of the
Clifton Hot Springs and San Francis-co
River Area, by J.E. Cunningham,
1981, scale 1:24,000.
OFR 81-30-Reconnaissance Geology-Salt
River From Roosevelt Dam to Granite
Reef Dam, Central Arizona, by R.B.
Scarborough, 1981, 70 p., scale
1:24,000 and 1:1,260,9 sheets.
OFR 826-Preliminary Geologic Map of
the Western Harquahala Mountains,
West-Central Arizona, by Stanley B.
Keith, S.J. Reynolds, and S.M. Rich-ard,
1982, scale 1:12,000. @ OFR 83-21-Map of Basin and Range
(Post-15 m.y.a.) Exposed Faults, Gra-bens,
and Basalt-Dominated Volca-nism
in Arizona, by R.B. Scarborough,
C.M. Menges, and P.A. Pearthree,
1983,25 p., scale 1:500,000,2 sheets.
OFR 83-24-Reconnaissance Geology of
the Northern Plomosa Mountains, by
R.B. Scarborough and Norman Mead-er,
1982,35 p.
OFR 84-1-Late Pliocene and Quaternary
Geology, Ajo Quadrangle, by R.B.
Morrison, 1983,6 p., scale 1:250,000.
OFR 84-2-Late Pliocene and Quaternary
Geology, El Centro Quadrangle, by
R.B. Morrison, 1983, 6 p., scale
1:250,000.
OFR 843-Late Pliocene and Quaternary
Geology, Lukeville and Sonoyta Quad-rangles,
by R.B. Morrison, 1983, 6 p.,
scale 1:250,000.
OFR 84-4-Preliminary Geologic Map of
the Aguila Ridge-Bullard Peak Area
(Eastern Harcuvar Mountains), West-
Central Arizona, by S.J. Reynolds and
J.E. Spencer, 1984, 2 p., scale
1:24,000.
OFR 85-2-Geologic Cross Sections of
Western Arizona Basin and Range,
With Accompanying Geologic Maps
and Other Information, by R.B. Scar-borough,
1985, 10 p., scale 1:250,000,
35 sheets.
OFR 85-5-Reconnaissance Geologic Map
of the Merritt Hills, Southwestern
Yavapai County, Arizona, by S.J. Rey-nolds
and J.E. Spencer, 1985, scale
1:24,000.
OFR 856-Reconnaissance Geology of
Mineralized Areas in Parts of the
Buckskin, Rawhide, McCracken, and
Northeast Harcuvar Mountains, West-ern
Arizona, by J.E. Spencer and
J.W. Welty, 1985,31 p.
OFR 85-9-Geologic Map of the Little
Harquahala Mountains, West-Central
Arizona, by J.E. Spencer, S.M. Rich-ard,
and S.J. Reynolds, 1985, 18 p.,
scale 1:24,000,3 sheets.
OFR 85-11-Reconnaissance Geology of
the Crest of the Sierra Estrella,
Central Arizona, by J.E. Spencer, S.J.
Reynolds, Phillip Anderson, and J.L.
Anderson, 1985,20 p.
OFR 85-14-Preliminary Geologic Maps
of the Eastern Big Horn and Belmont
Mountains, West-Central Arizona, by
R.C. Capps, S.J. Reynolds, C.P. Korte-meier,
J.A. Stimac, E.A. Scott, and
G.B. Allen, 1985, 26 p., scale 1:24,000,
2 sheets.
OFR 86-2-Geologic Map of the Lincoln
Ranch Basin, Eastern Buckskin Moun-tains,
Western Arizona, by J.E. Spen-cer
and S.J. Reynolds, 1986, 6 p.,
scale 1:24,000.
OFR 86-9-Geologic Map of the Planet-
Mineral Hill Area, Northwestern
Buckskin Mountains, West-Central 1
Arizona, by J.E. Spencer, S.J. Rey-nolds,
and N.E. Lehman, 1986, 13 p.,
scale 1:24,000.
OFR 86-lO-Geologic Map of the North-eastern
Hieroglyphic Mountains, Cen-tral
Arizona, by R.C. Capps, S.J.
Reynolds, C.P. Kortemeier, and E.A.
Scott, 1986,16 p., scale 1:24,000.
OFR 87-2-Geologic Map of the Swan-seacopper
Penny Area, Central
Buckskin Mountains, West-Central
Arizona, by J.E. Spencer and S.J.
Reynolds, 1987,lO p., scale 1:12,000.
OFR 87-4-Geologic Map of the Maricopa
Mountains, Central Arizona, by Dick-son
Cunningham, Ed DeWitt, Gordon
Haxel, S.J. Reynolds, and J.E. Spen-cer,
1987, scale 1:62,500.
OFR 87-9-Geologic Map of the Wicken-burg,
Southern Buckhorn, and North-western
Hieroglyphic Mountains,
Central Arizona, by J.A. Stimac, J.E.
Fryxell, S.J. Reynolds, S.M. Richard,
M.J. Grubensky, and E.A. Scott, 1987,
13 p., scale 1:24,000,2 sheets.
OFR 87-lO-Geologic Map of the North-eastern
Vulture Mountains and
Vicinity, Central Arizona, by M.J.
Grubensky, J.A. Stimac, S.J. Reynolds,
and S.M. Richard, 1987, 7 p., scale
1 :24,000.
OFR 88-I-Geologic Map of the Southern
Hieroglyphic Mountains, Central Ari-zona,
by D.E. Wahl, S.J. Reynolds,
R.C. Capps, C.P. Kortemeier, M.J.
Grubensky, E.A. Scott, and J.A.
Stimac, 1988,6 p., scale 1:24,000.
OFR 88-4-Quaternary Geologic Map of
the Salome 30 x 60-Minute Quad-rangle,
West-Central Arizona, by K.A.
Demsey, 1988, scale 1:100,000.
OFR 88-9-Geologic Map of the South-eastern
Vulture Mountains, West-
Central Arizona, by M.J. Grubensky
and S.J. Reynolds, 1988, 16 p., scale
1:24,000.
OFR 88-lO-Geologic Map of the Vulture
Mine Area, Vulture Mountains, West-
Central Arizona, by S.J. Reynolds,
J.E. Spencer, Ed DeWitt, D.C. White,
and M.J. Grubensky, 1988, 5 p., scale
1 :24,000. ' Indexes I M 17-Index of Published Geologic Maps
of Arizona, 1903-1982, by R.B. Scar-
borough and M.L. Coney, 1982, scale
1:1,000,000,6 plates.
OFR 84-5-Index of Published Geologic
Maps of Arizona, November 1982-June
1984, by R.B. Scarborough and T.G.
McGarvin, 1984, scale 1:1,000,000.
OFR 86-4-Index of Published Geologic
Maps of Arizona, July 1984-December
1985, by T.G. McGarvin, 1986, scale
1:1,000,000.
OFR 87-1-Index of Published Geologic
Maps of Arizona-1986, by T.G.
McGarvin, 1987, scale 1:1,000,000.
OFR 87-5-Index of Unpublished (Pre-
1969) Geologic Maps in Arizona Done
by the Arizona Bureau of Mines and
the U.S. Geological Survey, by M.J.
Grubensky and S.J. Reynolds, 1987,
scale 1:250,000,14 sheets.
OFR 88-16-Index to Published Geologic
Maps of Arizona-1987, by T.G.
McGarvin, 1988, scale 1:1,000,000.
(continued from page 2)
and areas of Mesozoic or early Cenozo-ic
metamorphism.
(7) Precambrian rocks throughout the
State have been subdivided into new
categories. The older Precambrian meta-morphic
rocks, shown as gneiss and
schist on the 1969 map, have been sub-divided,
where sufficient information
exists, into metasedimentary rocks,
metavolcanic rocks, and metamorphosed
granitic rocks. Precambrian granitic
rocks, previously shown as one map unit,
have been subdivided into two suites of
different ages.
(8) The ages assigned to many bed-rock
exposures have changed because of
recent data. For example, rocks shown
on the 1969 map as Mesozoic or Tertiary
gneiss in southwestern Arizona are now
shown as Precambrian gneiss, Precam-brian
granite, Jurassic granite, and
Tertiary to Cretaceous granite. Some
areas originally shown as Precambrian
gneiss are instead Tertiary, Cretaceous,
and Jurassic granites that were affected
by Mesozoic metamorphism and Tertiary
mylonitization.
The new State map, although printed
at a scale of 1:1,000,000, was compile 0' at 1:500,000 (the scale of the 1969 State
map) and photographically reduced to
1:1,000,000 prior to color separation by
computer. A new 1:500,000-scale State
geologic map is planned, but will not be
printed until additional geologic mapping
in western Arizona and in the Transition
Zone is completed, probably after 1990.
Until then, the 1:1,000,000-scale map will
represent an interim statement concern-ing
.what is and what is not known
about the geology of Arizona.
To obtain a copy of the new Geologic
Map of Arizona, send $5.00 plus a post-age
and handling fee (add $1.75 for a
folded map; add $2.75 for a rolled map).
All orders must be prepaid. Make the
check or money order payable to the
Arizona Geological Survey and mail it to
the AZGS offices at 845 N. Park Ave.,
#loo, Tucson, AZ 85719.
DEBRIS FLOW THREATENS ARIZONA HOMES
In July 1988, a significant debris flow threatened several homes near a small
tributary of Ash Creek in the Huachuca Mountains of southeastern Arizona. A for-est
fire in June denuded vegetation from the middle and upper portions of this
drainage. During an intense thunderstorm in the area, water runoff and fine-grained
sediments from the steep slopes of the upper portion of the drainage formed
a slurry, which entrained boulders from the stream channel. The above photo shows
boulders that were deposited on an alluvial fan where the stream exits the moun-tains.
Although houses on the alluvial fan were not seriously damaged, yards were
rearranged as debris flowed among several houses. Before this event, researchers
and reaulatory agencies had not considered debris flows a serious threat in the
area. The ~ r & o nGi eological Survey (AZGS) is involved in a study to (1) determine
the physical properties of this debris flow; (2) assess the frequency of debris flows - in this drainage; and (3) evaluate evidence for debris flows-in other drainages in
the Huachuca Mountains. This information will enable AZGS staff members to assess
the extent of debris-flow hazards in this mountain range.
4 Arizona Geology, vol. 18, no. 3, Fall 1988
Alternatives in Flood-Plain Management in Desert Areas
by Marie Slezak Pearthree
and Victor R. ~ a k e r
One of Arizona's most damaging geo-logic
hazards has been water runoff
from normally dry desert lands. Process-es
associated with this phenomenon are
especially troublesome in the lowlands of
the Basin and Range province, where
more than 90 percent of the State's rap-idly
expanding population resides. Run-off
intensity can range from low flows
contained within erodible banks to over-bank
flooding onto adjacent flood plains.
Less attention has been given to the
management problems associated with
shifting banks during "low" flows than
to those caused by classic flooding.
In the southwestern United States,
frequent changes in the morphology and
position of alluvial ephemeral-stream
channels create uncertainties for flood-plain
management. These stream chan-nels
are developed within unconsolidated
fluvially deposited sediments and convey
flows resulting from direct precipitation
or snowmelt (Gary and others, 1974;
Maddock, 1976). The channels are usually
dry for long periods or carry only occa-sional
low flows. Infrequent high flows
may exceed channel capacities and local-ly
inundate adjacent flood plains (Condes
de la Torre, 1970). A flood plain is geo-logically
defined as the nearly level
land adjacent to a stream channel that
is constructed by the stream and is sub-ject
to flooding (Gary and others, 1974).
It is conceptually important to distin-guish
between flood and flow events in
the semiarid Southwest. Much confusion
has arisen because of a lack of appreci-ation
for the contrasting processes
involved in these two types of runoff
events. A flood occurs when the capacity
of an active channel to contain the flow
is exceeded. In other words, a true flood
refers to distinct overbank flow. If there
is no flooding, the runoff event is sim-ply
a flow event. Flooding may locally
occur, but elsewhere along the same
stream channel, runoff may be totally
contained within well-defined banks.
Flooding is an unusual condition, where-as
confined flow is the norm.
Federal flood-plain management regu-lations,
formulated by the U.S. Congress
in response to past and potential loss of
life and property from flooding, form
' ~ e i l a Barr Associates, Inc., 2075 N. 6th Ave.,
Tucson, AZ 85705
2~ept. of Geosciences, University of Arizona,
Tucson, AZ 85721
the basis for local flood-plain manage-ment.
These regulations, however, do
not take into account regional differ-ences
in streamchannel behavior. The
Federal regulations mainly address in-channel
and overbank inundation pro-duced
by a 100-year flood, which has a
1 percent chance of occurring in any
given year (U.S. Code Congressional and
Administrative News, 1968). The limits
Channel Change Along the Rillito Creek
System of Southeastem Arizona
1941 Through 1983
lmplicalians for Fld-Plain Management
Special Papcr6
of the resulting 100-year flood plain
generally occur within the geologic flood
plain.
Land-use restrictions are mandated
within the regulatory flood plain, which
currently consists of the 100-year flood
plain, by Federal regulations for commu-nities
that want to participate in the
National Flood Insurance Program. In the
southwestern United States, however,
channel-bank erosion often presents an
equal or greater hazard to property than
does flooding. This additional hazard is
not addressed in the Federal regulations,
nor is it often brought to the attention
of communities enacting flood-plain man-agement
programs.
Changes in channel morphology
(cross-sectional channel shape and plan-view
patterns) and position, including
both abrupt and long-term bank erosion,
have modified the limits of 100-year
flood plains. The computational methods
generally used to predict the water-surface
level of a 100-year flood along a
stream, and thus determine the limits of
its 100-year flood plain, assume that
neither the morphology nor the position
of the channel will change significantly
before or during the flood (Burkham,
1972). This assumption is often invalid
when applied to the alluvial channels of
ephemeral streams in semiarid regions.
Such streams frequently alter the posi-tions
of their channel banks and eleva-tions
of their streambeds during flows of
lesser magnitude and greater frequency
than the 100-year flood. Temporal vari-ability
of 100-year flood-plain limits
makes land-use zoning based on nation-ally
mandated regulatory procedures
invalid in the semiarid Southwest.
It is crucial in terms of land use to
determine if property near a stream
channel is potentially subject to bank
erosion, flooding, or both. There is,
therefore, a need to modify Federal
flood-plain management regulations in
semiarid regions to include the effects
of channel change on the extent of the
regulatory flood plain and the potential
erosional damage associated with both
flood and nonflood flows. If the defini-tion
of the regulatory flood plain were
to take into account (1) past channel
positions and (2) potential sites of bank
erosion and lateral channel migration,
regulatory flood plains would be less
dependent upon present stream-channel
morphologies and positions, and thus less
prone to short-term fluctuations. Ac-cordingly,
for management purposes, the
concept of the regulatory flood plain
should be amended to include both his-torical
channel positions and river mar-gins
potentially subject to erosion or
flooding. Flood-plain management should
include management of the stream chan-nels
and their margins, as well as the
flood vlains.
A iecent publication released by the
Arizona Geological Survey explores the
historical behavior of the Rillito Creek
system of southeastern Arizona. This
ephemeral-stream system drains 934
square miles (2,419 square kilometers)
within the Basin and Range Province.
Based on investigations of this system,
alternatives to the flood-plain manage-ment
regulations currently applied to
semiarid regions have been proposed.
The Rillito Creek system was chosen
because severe bank erosion and lateral
channel migration have occurred during
the past few decades within the rapidly
expanding Tucson metropolitan area. The
study area lies within the Tucson basin
primarily to the north and east of the
current city limits. Population growth,
exemplified by the influx of approxi-mately
195,000 persons into Pima County
Arizona Geology, vol. 18, no. 3, Fall 1988 5
between 1965 and 1985, has created
substantial pressure to urbanize the
stream margins of this drainage system
(Pima County Planning and Development
Services, oral commun., 1985). An'under-standing
of the nature of this system is
therefore required for setting develop-ment
restrictions.
The behavior of the Rillito Creek
system was investigated primarily by
mapping Tanque Verde Creek, Pantano
Wash, and Rillito Creek from aerial
TUCSON STORMWATER
MANAGEMENT STUDY
The City of Tucson is developing
a comprehensive plan to mitigate
drainage problems associated with
runoff from storms. The Tucson
Stormwater Management Study team
will search for solutions that incor-porate
(1) a balance between solving
drainage problems and protecting the
natural environment; (2) costs for
improving and maintaining facilities;
and (3) requirements for forming and
running an organization that will
ge the program. After the study
determines acceptable solutions,
1 review funding options for the
rogram and develop guidelines for
ts annual review and update. Meet-s
to gather public input to help
e the program will be held in
1988, January 1989, and
Locations will be an-photographs
generated between 1941 and
1979. From these photos, channel-width
measurements we& obtained at selected
locations along each stream channel and
comparisons were made of channel plan-view
patterns and positions through
time. In addition, historical observations
of channel change were gathered from
newspaper accounts. Longitudinal pro-files
from the Pima County Department
of Transportation and Flood Control Dis-trict
provided insight into fluctuations in
streambed elevations. This investigation
was subsequently updated using aerial
photographs to include the effects of
the flow event of October 1983.
The results of this study were orga-nized
to provide an understanding of
(1) the nature of channel change within
ephemeral-stream systems in semiarid
regions and (2) the management prob-lems
that such change creates. Observed
variations in channel morphology and
position were evaluated with respect to
streamflow history and bank composi-tions.
The effects of in-channel sand-and-
gravel extraction on channel mor-phology
were also considered.
The study delineates Federal flood-plain
management regulations through a
survey of the legislation that led to the
establishment of the National Flood
Insurance Program. Pima County and
City of Tucson flood-plain management
ordinances are also outlined. Applicabil-ity
of Federal regulations to ephemeral-stream
systems in semiarid regions is
discussed, using the Rillito Creek system
as an example. Recommendations are
then made for more effective flood-plain
management in such regions.
Channel Change Along the Rillito Creek
System of S o ~ t h m t A~riz ona, 1941
Through 1983: Implications for Flood-Plain
Management was published as Special
Paper 6. This 58-page study includes a
1:24,000-scale map showing the historical
channel boundaries of this river system.
A copy may be obtained by sending
$16.00, plus $4.25 for postage and han-dling,
to the Arizona Geological Survey,
845 N. Park Ave., Tucson, AZ 85719.
All orders must be prepaid.
References
Burkham, D.E., 1972, Channel changes of the Gila
River in Safford Valley, Arizona, 1846-1970:
U.S. Geological Survey Water-Supply Paper
655-G, 24 p.
Condes de la Torre, A.C., 1970, Streamflow in the
upper Santa CNZ basin, Santa Cruz and Pima
Counties, Arizona: U.S. Geological Survey
Water-Supply Paper 1939-A, 26 p.
Gary, Margaret, McAfee, Robert, Jr., and Wolf, C.
L., eds., 1974, Glossary of geology: American
Geological Institute, 858 p.
Maddock, Thomas, Jr., 1976, A primer on flood-plain
dynamics: Journal of Soil and Water
Conservation, v. 31, no. 2, p. 44-47.
U.S. Code Congressional and Administrative
News, 1968, 90th Congress, 2nd session, v. 1
and 2: St. Paul, West Publishing Co.
STAFF NOTES
Thomas G. McGarvin was a panelist
on the Sunday-morning series titled
"Arizona Alumni: which aired on Jun*
19 on KGUN-TV (Channel 9, ABC affili-ate).
The program included discussions
on the history of gold mining and the
geology of gold deposits in Arizona, as
well as a demonstration of gold panning.
Stephen J. Reynolds presented a talk
on Tertiary volcanism at the CACTIS
meeting, which was held in Flagstaff in
May. At an industrial minerals workshop
held in Tempe in May, he discussed
sources of geologic information in Arizo-na.
Reynolds appeared on the program
"Horizon" on KAET-TV (Channel 8, PBS
affiliate), which was shown on October
3, to discuss the geology of Papago Park
in Phoenix. He also led a field trip to
the Rincon Mountains near Tucson for
faculty and graduate students from the
University of Arizona and a visiting pro-fessor
from Germany.
Jon E. Spencer presented a talk titled
"Mesozoic and Cenozoic Geology and
Mineral Deposits of West-Central Arizo-na"
to the Arizona Geological Society on
October 4.
John W. Welty was a guest on the
program "Horizon," which aired July 25
on KAET-TV. Titled "Arizona SSC Proj-ect
Update," the program focused on
the geologic setting and constructability
of the Superconducting Super Collider C
(SSC). The proposed SSC site in Arizona
encompasses the Maricopa Mountains
southwest of Phoenix. Welty, Project
Geologist for the Arizona SSC Project,
has been "on loan" to the SSC team
from the AZGS staff since April 1987.
Arizona Geology, vol. 18, no. 3, Fall 1988
CACTIS Meeting Examines Crustal Transect
by John & Sassf Gordon B. Haxel.
and Ivo Lucchitta
U.S. Geological Survey
Flagstaff, AZ 86001
1 A workshop examining the geology, 1 evolution, structure, and tectonics of the
eastern two-thirds of the U.S. Geological
Survey Pacific to Arizona Crustal Exper-iment
(PACE) transect was held in Flag-staff
May 6-8, 1988. The meeting, called
"California-Arizona Crustal Transect:
Interim S.ynthesisw (CACTIS), was
organized by personnel from the U.S.
Geological Survey and Northern Arizona
University. A total of 88 persons repre-senting
several disciplines and about 20
institutions attended.
The workshop was characterized by
an atmosphere of informality, fostered in
large part by the absence of formal pre-sentations
and the availability of abun-dant
poster space. Nine 1-hour panel
discussions were held and more than 30
posters were displayed during the work-shop.
Each panel consisted of 5 to 7
ersons famifiar with the topic under
iscussion; audience participation was
usuallv livelv.
hi f o k panel discussions held on
May 6 focused on a synoptic view of the
transect, from the Colorado Plateau
westward through the Transition Zone
into the Sonoran Desert of the Basin
and Range Province. The highly extended
terranes on both sides of the Colorado
River were discussed during one session;
other discussions were devoted to the
Mojave block and eastern Mojave Desert.
Many new insights were developed
regarding the present state of the tran-sect.
Seismic refraction and reflection
data recently obtained by PACE,
COCORP, and CALCRUST were especial-ly
significant. Spirited discussions were
held on the "Bagdad reflection sequence"
and the "bulge of pain," a midcrustal
anticlinal structure under the metamor-phic
core complexes. The specter of sig-nificant
velocity anisotropy in layered
mid- to lower-crust rocks was raised by
evidence from velocity measurements on
core from a hole in the Appalachian
Piedmont metamorphic province. New
and somewhat controversial geobaromet-ric
data provided evidence of consider-able
variability in the depth of forma- II! on of metamorphic core complexes:
ome are shallow, others are deep.
On the second day, emphasis shifted
from the current physical state of the
lithosphere to the evolution of the
present terranes and the processes that
controlled this evolution. Topics included
Proterozoic through Tertiary inheritance,
as well as lower-crust/lithospheric pro-cesses,
with emphasis on the significance
of seismic reflectors and refractors
(once again raising the specter of veloc-ity
anisotropy) and lithosphere rheology.
The role of thermal time-constants in
the contemporary thermal expression of
previous thermal and tectonic events was
emphasized. A lively debate on
extension and magmatism revolved
around the geologic evidence that sub-stantiates
various hypotheses concerning
the order of their occurrence and
whether one can occur without the
other. The panel discussions ended with
a plate-tectonic panorama featuring shal-low
subducting slabs, thin-skin tectonics,
drips, and gaps.
On the last day, participants synthe-sized
what had been learned during the
meeting and made some progress toward
greater interdisciplinary and interinstitu-tional
cooperation within the transect.
Several fascinating questions were
raised: (1) What happened between 30
and 40 m.y. ago (Figure I), from which
time little tectonic or magmatic activity
can be documented? Were tectonic
events occurring, but to the east? (2)
How can deep crust (core complexes) be
exposed by extension? (3) Was the
region once as high as today's Tibetan
Plateau? (4) What is the relation
between Mesozoic crustal thickening and
Tertiary crustal extension? These and
other questions will be addressed in a
special issue of the Journal of Geophysical
Research, which will be published in
late 1989.
Southeastern
California West-Central
a a
Southeastern Southwestern Southwestern
California Arizona Arizona
Southwest
Transition Colorado
Zone Plateau
@ Thrust faulting @ uplift
@ Crustal extension 8 Erosion
@ Magmatism
@ Clastic deposition
Figure 1. Approximate occurrence of major tectonic activity along the California-Arizona
Crustal Transect. Source: conmsus of CACTIS attendees.
Arizona Geology, vol. 18, no. 3, Fa11 1988 7
Dangers In and Around Abandoned Mines
The following article was originally
released as a brochure by the Education
and Training Division of the Arizona
State Mine Inspector's Office. For fur-ther
information, write to Arizona State
Mine Inspector's Office, Abandoned
Mines Program, 1616 W. Adams, Suite
411, Phoenix, AZ 85007-2627, or call
(602) 255-5971.
Abandoned mines pose numerous
hazards to the unwary curiosity seeker
or amateur prospector. Whatever the po-tential
for undiscovered treasure, the
doubtful rewards are not worth the
almost inevitable costs in disaster, dis-memberment,
or even death. The dangers
that could be encountered in an aban-doned
mine include shafts, cave-ins,
timber, ladders, explosives, water, bad
air, and rattlesnakes.
Shafts
The collar or top of a mine shaft is
especially dangerous. The fall down a
deep shaft is just as lethal as the fall
from a tall building, with the added dis-advantage
of bouncing from wall to wall
and the likelihood of having falling
rocks and timber for company. Even if a
person survived such a fall, it might be
impossible to climb back out.
The rocks at the surface are often
decomposed. Timbers may be rotten or
missing. It is dangerous to walk any-where
near a shaft opening; the entire
area could slide into the shaft, along
with the curious explorer.
A shaft sunk inside a tunnel is called
a winze. In many old mines, winzes have
been boarded over. If these boards have
decayed, a perfect trap is awaiting the
next hapless visitor.
Cave-Ins
Cave-ins are an obvious danger.
Areas that are likely, to cave in are
often hard to detect. Minor disturbances,
such as vibrations caused by walking or
speaking, could cause a cave-in. If a
person were caught, he or she could be
crushed to death. An even worse scenar-io
would involve being trapped behind a
cave-in when no one else is aware of
the situation. Death could occur through
starvation, thirst, or gradual suffocation.
Timber
The timber in abandoned mines can
be weak from decay. Other timber, al-though
apparently in good condition,
may become loose and fall at the slight-est
touch. A well-timbered mine opening
can look very solid when, in fact, the
timber can barely support its own
weight. There is the constant danger of
inadvertently touching a timber and
causing the tunnel to collapse.
Ladders
Ladders in most abandoned mines are
unsafe. Ladder rungs may be missing or
broken. Some will fail under the weight
of a child because of dry rot. Vertical
ladders are particularly dangerous.
Explosives
Many abandoned mines contain old
explosives left by previous workers.
These are extremely dangerous. Explo-sives
should never be handled by anyone
who is unfamiliar with them. Even ex-perienced
miners hesitate to handle old
explosives. Old dynamite sticks and
caps can explode if stepped on or even
touched.
Water
In many tunnels, water forms deep
pools or conceals holes in the floor.
Pools of water are also common at the
bottom of shafts. It is usually impossible
to estimate the depth of the water; a
false step could lead to drowning.
Bad Air
"Bad air" contains poisonous gases or
insufficient oxygen. Poisonous gases can
accumulate in low areas or along the
floor. A person may enter such areas
breathing the good air above the gases,
but the motion caused by walking will
mix these gases with the good air, pro-ducing
a possibly lethal mixture to be
inhaled on the return trip.
Because little effort is required to go
down a ladder, the effects of "bad air"
may not be noticed. When climbing out
of a shaft, however, a person requires
more oxygen and will breathe more
deeply. The result is dizziness, followed
by unconsciousness. If the gas doesn't
kill, the fall will.
Rattlesnakes
Old mine tunnels and shafts are
among the rattlers' favorite haunts, to
cool off in summer or to search for ro-dents
and other small animals. Any hole
or ledge, especially near the entrance of
the tunnel or shaft, can conceal a snake.
Rescue Problems
No inexperienced person should
attempt to rescue the victim of a mine
accident. The county sheriff should be
called instead because he or she is in
the best position to organize a rescue
operation.
Attempting to rescue a person from a
mine accident is usually difficult and
dangerous for both the victim and the
rescuer. Even professional rescue teams
face death or injury, though they are
trained to avoid all unnecessary risks. It
makes no sense to kill one person to
rescue another. Everyone, adults as well
as children, should consider these ex-treme
dangers when they are tempted to
enter abandoned mines.
Vandalism
Those who remove tools, equipment,
building materials, and other objects
from mines and buildings near mines do
not go home with souvenirs, but with
stolen property. Many mines that look
abandoned are private property; they are
only idle, waiting to be reworked. Warn-ing
signs and fences are there for
reason. Unauthorized removal or damag
to signs or fences is a class 6 felony.
Safety Summary
There is only one safe way to deal
with abandoned mines: stay out!
Additions to the Arizona Geological Survey Library
The following publications were re-cently
added to the Arizona Geological
Survey library, where they may be ex-amined
during regular working hours.
Copies may also be obtained from the
respective publishers.
U.S. Bureau of Mines
Bulletin
689-Pankratz, L.B., Mah, A.D., and Wat-son,
S.W., 1987, Thermodynamic prop-erties
of sulfides, 427 p.
Information Circulars
9131-Sousa, L.J., Yaremchuk, E.H., and
Graham, A.P., 1987, Foreign direct in-vestment
in the U.S. minerals industry,
24 p.
9152-Boldt, C.M.K., and Scheibner, B.J.,
1987, Remote sensing of mine waste,
43 p.
9170-Stebbins, S.A., 1987, Cost estima-tion
handbook for small placer mines,
94 p.
9182-Sanders, M.S., and Peay, J.M.,
1988, Human factors in mining, 153 p. 0 183-USBM, 1988, Mine drainage and
surface mine reclamation, v. 1, mine
water and mine waste, 413 p.
9184-USBM, 1988, Mine drainage and
surface mine reclamation, v. 2, mine
reclamation, abandoned mine lands
and policy issues, 401 p.
i Mineral Land Assessment Reports
! MLA-34-87-Lundby, William, 1987, Min-
I eral resources of the Coyote Moun- I tains Wilderness Study Area (AZ-020-
1 202), Pima County, Arizona, 25 p.,
I scale 1:24,000.
I MLA-80-87-Kreidler, T.J., 1987, Mineral
investigation of the Ragged Top Wil-derness
Study Area (AZ-020-1971, Pima
County, Arizona, 14 p., scale 1:24,000.
MLA-7-88-Korzeb, S.L., 1988, Mineral
investigation of the Sierra Estrella
Wilderness Study Area (AZ-020-160),
Maricopa County, Arizona, 12 p.
MLA-9-88-Almquist, C.L., 1988, Mineral
investigation of the Mount Tipton Wil-derness
Study Area (AZ-020-012/042)
and proposed additions, Mohave Coun-ty,
Arizona, 12 p.
MLA-11-88-Wood, R.H., 11, 1988, Miner-al
resources of a part of the Muggins
Mountains Wilderness Study Area
(AZ050-053A), Yuma County, Arizona,
17 p.
MLA-25-88-~ane, M.E., 1988, Mineral
investigation of additional parts of the
rizona Geology, vol. 18, no. 3, Fall 1988
Arrastra Mountain Wilderness Study
Area (AZ-020-059), La Paz, Mohave,
and Yavapai Counties, Arizona, 25 p.,
scale 1:62,500.
Reports of Investigations
9122-Lei, K.P.V., and Carnahan, T.G.,
1987, Silver-catalyzed oxidative leach-ing
of an arsenical copper sulfide con-centrate,
14 p.
9126-Pahlman, J.E., Rhoades, C.A., and
Chamberlain, P.G., 1987, Dual leaching
method for recovering silver and man-ganese
from domestic manganiferous
silver deposits, 8 p.
9138-Dannenberg, R.O., Gardner, P.C.,
Crane, S.R., and Seidel, D.C., 1987,
Recovery of cobalt and copper from
complex sulfide concentrates, 20 p.
9150-Pahlman, J.E., and Khalafalla, S.E.,
1988, Leaching of domestic manganese
ores with dissolved SO2, 15 p.
9181-Eisele, J.A., Hunt, A.H., and Lamp-shire,
D.L., 1988, Leaching gold-silver
ores with sodium cyanide and thiourea
under comparable conditions, 7 p.
Special Publications
McColly, R.A., and Anderson, N.B., 1987,
Availability of federally owned miner-als
for exploration and development in
western states, Arizona, 1986,27 p.
USBM, 1988a, Bureau of Mines research
87, a summary of significant results in
mineral technology and economics, 93
P .
- 1988b, Issues and needs of the
mining industry, a Bureau of Mines
perspective, 28 p.
U.S. Geological Survey
Bulletins
1671-McIntyre, D.H., 1988, Volcanic
geology in parts of the southern Pel-oncillo
Mountains, Arizona and New
Mexico, 18 p.
1672-Billingsley, G.H., 1987, Geology and
geomorphology of the southwestern
Moenkopi Plateau and southern Ward
Terrace, Arizona, 18 p.
1683-A-Wenrich, K.J., Van Gosen, B.S.,
Balcer, R.A., Scott, J.H., Mascarenas,
J.F., Bedinger, G.M., and Burmaster,
Betsi, 1988, A mineralized breccia pipe
in Mohawk Canyon, Arizona, lithologic
and geophysical logs, 66 p.
1685-Franczyk, K.J., 1988, Stratigraphic
revision and depositional environments
of the Upper Cretaceous Toreva For-mation
in the northern Black Mesa
area, Navajo and Apache Counties,
Arizona, 32 p.
1693-Cox, D.P., and Singer, D.A., eds.,
1986, Mineral deposit models, 379 p.
1694-Bush, A.L., ed., 1987, Contributions
to mineral resources research, 1984,
104 p.
1701-A-Gray, Floyd, Miller, R.J., Has-semer,
J.R., Hanna, W.F., and Brice,
J.C., 111, 1987, Mineral resources of
the Big Horn Mountains Wilderness
Study Area, Maricopa County, Arizona,
14 p., scale 1:62,500.
1701-B-Miller, R.J., Gray, Floyd, Has-semer,
J.R., Hanna, W.F., Brice, John,
111, and Schreiner, Russell, 1987, Min-eral
resources of the Lower Burro
Creek Wilderness Study Area, Mohave
and Yavapai Counties, Arizona, 22 p.
1703-C-Simons, F.S., Theobald, P.K.,
Tidball, R.R., Erdman, J.A., Harms,
T.F., Griscom, Andrew, and Ryan, G.S.,
1987, Mineral resources of the Black
Rock Wilderness Study Area, Graham
County, Arizona, 9 p., scale 1:24,000.
1798-Schmitt, L.J., 1988, A review of
the association of petroliferous materi-als
with uranium and other metal
deposits in sedimentary rocks in the
United States, 18 p.
1802-Wheeler, R.L., and Krystinik, K.B.,
1987, Evaluating coinciding anomalies
along a fault trace or other traverse,
simulations and statistical procedures,
12 p.
Maps
GQ-1603-Sargent, K.A., and Philpott, B.
C., 1987, Geologic map of the Kanab
quadrangle, Kane County, Utah, and
Mohave and Coconino Counties, Arizo- I
na, scale 1:62,500.
I-1310-E-Watts, K.C., and Hassemer, J.
R., 1988, Geochemical interpretive and
summary maps, Silver City lo x 2'
quadrangle, New Mexico and Arizona,
scale 1:250,000,2 sheets.
I-1662-Drewes, Harald, 1987, Geologic
map and cross sections of the Dragoon
Mountains, southeastern Arizona, scale
1:24,000.
I-1778-Sutphin, H.B., and Wenrich, K.J.,
1988, Map showing structural control
of breccia pipes on the southern Mar-ble
Plateau, north-central Arizona,
scale 1:50,000.
I-1793-Billingsley, G.H., 1987, Geologic
map of the southwestern Moenkopi
Plateau and southern Ward Terrace,
Coconino County, Arizona, scale
1:31,680.
I-1892-A-Laney, R.L., and Pankratz, L.
W., 1987, Investigations of land subsi-
New Publications From the Arizona Geological Survey
The following p~iblications may be
chased over the counter or by mail
from the Arizona Geological Survey
(AZGS), 845 N. Park Ave., Tucson, AZ
85719. For price information on these
and other AZGS publications, contact
the AZGS offices at (602) 621-7906.
Reynolds, S.J., 1988, Geologic map of
Arizona: Map 26, scale 1:1,000,000.
See "A New Geologic Map of Arizo-na"
on pages 2 and 4.
Welty, J.W. 1987, Volume 3, geology
and tunneling of the Maricopa Supercon-ducting
Super Collider site proposal:
Open-File Report 88-7,260 p.
In 1983 the State of Arizona began a
statewide search for an appropriate site
for the Superconducting Super Collider
(SSC). Of the many criteria outlined for
site evaluation by the U.S. Department
of Energy (DOE), the greatest weight
was given to geology and tunneling and
its impact on construction and opera-tional
costs. This report is a copy of
the Geology and Tunneling chapter filed
with the DOE. Topics include geology,
geohydrology, seismicity, faulting, tun-ling
and underground construction,
d estimated project costs and sched-ules
for the Maricopa site.
Welty, J.W., 1987, Volume 3, geology and
tunneling of the Siem'ta Superconducting
Super Collider site proposal: Open-File
Report 88-8,270 p.
Although the DOE did not accept the
Sierrita site for the SSC, the geologic,
hydrologic, and geophysical investiga-tions
provided a wealth of information
about this area. This report is a copy of
the Geology and Tunneling chapter filed
with the DOE.
offers much potential for undiscovered
ore deposits. Areas where the rocks
have been altered or mineralized have
been noted on the map. This open-file
map is a printed, not a blueline, copy.
Reynolds, S.J., Spencer, J.E., DeWitt, Ed,
White, D.C., and Grubensky, M.J., 1988,
Geologic map of the Vulture mine area,
Vulture Mountains, west-central Arizona:
Open-File Report 88-10, 5 p., scale
194,000.
The Vulture Mountains directly
southwest of Wickenburg contain one of
Arizona's premier historic gold deposits,
the Vulture mine. This mine yielded
about 340,000 ounces of gold and 260,000
ounces of silver, with average grades of
0.35 oz/ton gold and 0.27 oz/ton silver.
Despite this significant production, the
mine has received relatively little geo-logic
study until recently. This geologic
map, which covers approximately 10
km centered on the mine, was com-pleted
to increase the understanding of
the geologic setting of this historically
important gold deposit.
Spencer, J.E., Emer, D.F., and Shenk,
J.D., 1988, Background radioactivity in
selected areas of Arizona and implica-tions
for indoor-radon levels: Open-
File Reporf 88-11,14 p.
This nontechnical summary of Open-
File Report 88-12 (listed below) was
prepared with special funding from the
Arizona State Legislature. It describes
the results of a ;econnaissance survey
of radioactivity caused by the natural
decay of uranium in rocks and soil.
These breakdown processes also produce
radon gas, which can accumulate in
buildings. Long-term inhalation of radon
may cause lung cancer in a small per-centage
of exposed individuals. The
products in selected populated areas of
Arizona: Open-File Reporf 88-12,88 p.
This technical report describes the
results of a reconnaissance survey that
measured radiation from bismuth-214, a
radondecay product, in the rocks and
soil of 38 inhabited areas in Arizona. It
outlines the methodology, lists the
radiometric values, and includes radioac-tivity
profiles and topographic maps of
the surveyed areas. Technical data are
included in this report; interpretations
of the results are given in Open-File
Report 88-11 (listed above).
Horstman, K.C., VandenDolder, EN., and
Reynolds, S.J., 1988, Bibliographic con-ventions
of the Arizona Geological Sur-vey:
Open-File Reporf 88-13,22 p.
The Arizona Geological Survey main-tains
a computerized database, named
AZBIB, containing more than 1,200 com-plete
citations of publications on the
geology of Arizona and neighboring
regions. While developing this database,
we established a set of bibliographic
conventions to maintain a consistent
format. The conventions presented in
this report largely follow those estab-lished
by the U.S. Geological Survey and
Geological Society of America, but are
more comprehensive. For this reason,
we are making these conventions avail-able
to persons outside the Arizona
Geological Survey. The database format
and bibliographic conventions are des-cribed
in this open-file report and are
illustrated with examples of the most
commonly cited types of publications.
Welty, J.W., Roddy, MS., Alger, C.S.,
and Brabb, E.E., 1988, Bibliography of
Arizona landslide maps and reports:
Open-File Report 88-14,13 p.
This report, the second in a series, is
1 Grubensky, M.J., and Reynolds, S.J., amo&t of radin generated is propor- an outgrowth of the U.S. Geological Sur- 1988, Geologic map of the southeartem tional to the amount of uranium and vey's ground-failure hazards-reduction
Vulture Mountains, west-central Arizona: uraniumdecay products in surrounding program. It lists 146 maps and reports
Oven-File Revort 88-9, 16 ,v .,, scale rocks and soil. Radon was not measured that identify more than 500 known Qua-
1 b4,000. in this study - only natural radioactiv- tcrnary mass movements in Arizona. The
The Vulture Mountains in wcst- ity lcvcls of rocks and soil. rcport provides a basis for increased un-central
Arizona lie bctwccn the Big Horn The study involved a survey of 38 lo- dcrstanding of the geologic scttings that
and Harquahala Mountains on the wcst calities within or near populated arcas arc prone to mass wasting in the State.
and the Wickcnburg Mountains on thc in Arizona. Portions of 6 of thcsc arcas
cast. This geologic map of the south- had radioactivity levels higher than the Scarborough, R-Bv atid Peauthree, P.A.,
eastern portion of the rangc, which "normal" reading for this study: Prcscott 1986, Reconnaissance assessmetlt of Qua-covcrs
the northern part of thc Wicken- (Granite Dclls), Cave Crcck, Camp ternary faultit% in the Gila River regiotl
burg SW 7.5-minute quadrangle, is Vcrde, Phoenix (a small area 1 mile from Sun Carlos Reservoir to coolidgel
important for three reasons: (1) the Vul- northcast of North Mountain Park), Arizona: Opetr-File Report 88-15, 12 p.,
re Mountains are largely unmapped; Tombstone, and Kirkland. scale 1950,000.
the Vulture Mountains contain an This map and report summarize evi-cellent
record of the mid-Tcrtiary Elner, D.F., Shetik, J.D., atid Spetlcer, J, dence of Quaternary faulting along the t structural and volcanic history of the E,, 1988, Reconnaissarice garnma-ray Gila River in central Arizona. The goal
rcgion; and (3) wcstncntral Arizona spectrometer survey of radoti-decay of the study was to delineate possible
Arizona Geology, vol. 18, no. 3, Fall 1988 11
A
Quaternary faults near existing and
potential dam sites. The study included
interpretation of aerial photographs,
helicopter overflight, and field recon-naissance
of suspicious features. Few
features were identified as possible
Quaternary faults.
McGarvin, T.G., 1988, Index to published
geologic maps of Arizona -- 1987: Open-
File Report 88-26, scale 1:1,000,000.
This index lists 49 sources of geo-logic
maps of the State published during
1987. References include publications of
the U.S. Geological Survey, Geological
Society of America, Arizona Geological
Society, Arizona Bureau of Geology and
Mineral Technology (Geological Survey
Branch), and other organizations. The
accompanying map identifies the areas
within Arizona covered by each
reference.
Arizona Geology 1 1 Vol. 18, No. 3 Fall 1988 1
State of Arizona: Governor Rose Mofford
Arizona Geological Survey
Director & State Geoloeist: Larrv D. Fellows
RADON
In September 1988 the Arizona Radia-tion
Regulatory Agency (ARRA) and the
U.S. Environmental Protection Agency
released, in summary form, the results of
their statewide indoor-radon survey.
Seven percent of the 1,700 homes tested
in Arizona contained greater than 4
picocuries per liter (pCi/l) radon. Only
11 measurements, from widely scattered
locations, were greater than 10 pCi/l. Of
the seven States surveyed, Arizona had
the lowest percentage of homes that
measured above the 4 pCi/l guideline
level. Approximately 30 percent of homes
in the other six States exceeded the 4
pCi/l level. More information on the
State radon survey may be obtained from
the ARRA in Phoenix (602-255-4845).
The Arizona Geological Survey
(AZGS) recently released the results of a
reconnaissance survey of background
uranium levels in populated areas in
Arizona. This was conducted to
determine the normal range of uranium
levels and to outline the location and
distribution of geologic materials in
populated areas that contain greater- I Editor: ~ L e lM~ . nv k d e n ~ o l d e r I ihan-normal levels of uranium. Because
Illustrators: Peter F. Corrao, Sherry F. Gamer uranium is the ultimate source of radon,
I _ ) homes built in areas with anomalous ura-
UPDATE
nium levels are at greater risk for hi
indoor-radon concentrations. Result
this survey indicate that some r
types in Prescott, the Cave Creek area,
the Phoenix Mountains, Camp Verde,
Kirkland, and Tombstone are slightly to
moderately higher in uranium than typi-cal
geologic materials in Arizona. (An
area in southwestern Tucson was previ-ously
known to be anomalous in urani-um.)
A summary of results has been
released as AZGS Open-File Report 88-
11; data and a description of technical
aspects of the survey are presented in
AZGS Open-File Report 88-12.
Arizona Geological Survey
845 N. Park Ave., #I00
Tucson, AZ 85719
TEL: (602) 621-7906