GEOTHERMAL RESOURCE POTENTIAL OF THE SAFFORD-SAN SIMON BASIN, ARIZONA
by James C. Witcher
Arizona Geological Survey Open-File Report 81-26
Arizona Geological Survey 416 W. Congress, Suite #100, Tucson, Arizona 85701
Funded By The U.S. Department ofEnergy Contract Number DE-FC07-79ID12009
This report is preliminary and has not been edited or reviewed for conformity with Arizona Geological Survey standards
NOTICE
This report was prepared to document work sponsored by the United States Government. Neither the United States nor its agents, the United States Department of Energy, nor any federal employees, nor any of their contractors, subcontractors or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, products or process disclosed, or represents that its use would not infringe privately owned rights.
Reference to a company or product name does not imply approval or recommen dation of the product by the Bureau of Geology and Mineral Technology or the U.S. Department of Energy to the exclusion of others that may be suitable.
i
TABLE OF CONTENTS
PAGE
List Of Figures
List of Tables
List 5f Appendices
Introduction 1
Land Status 3
Previous Work 4
Regional Setting 6
Regional Stratigraphy and Structure 12 Basement structure of the northern Safford-San Simon Basin 14 Basement structure of the southern Safford San Simon Basin 19
Basin and Range 21
Basin-Fill sediments in the Safford area 23
Basin-Fill sediments in the San Simon area 27
Indian Hot Springs-Gila Valley 29
Introduction 29 Geochemistry 29 Structure 29 Geothermometry 35 Conclusion 35
Buena Vista Area 37
Introduction 37 Geochemistry 37 Geology and Reservoir Characteristics 40
Cactus Flat-Artesia Area 50
Geology 50 Temperature Gradients 53 Mercury Soil Survey 59 Ground Water Chemistry and Geothermometry 61 Conclusion 68
ii Table of Contents (cont'd.)
PAGE
San Simon 69
Introduction 69 Thermal Regime 69 Geology 71 Geohydrology 74 Chemistry 74 Conclusion 77
Bowie Area 78
Introduction 78 Geochemistry 78 Structure and Stratigraphy 79 Active Tectonism 85 Conclusion 86
Whitlock Mountains Area 88
Tables 89-10.9
Appendices 110-120
Bibliography 121-131
iii FIGURES
PAGE
FIGURE 1 Map of thermal wells and springs (pocket)
FIGURE 2 Map of land status (pocket)
FIGURE 3 Location map of study area and physiographic provinces 7
FIGURE 4 Regional lineaments and crustal discontinuities 9
FIGURE 5 Map of inferred Tertiary basement lithology in southeastern Arizona 15
FIGURE 6 Major geologic structure in the Safford area 30
FIGURE 7 Schlumberger resistivity profile near Safford 33
FIGURE 8 Map showing areas with low electrical resistivity and wells which encounter evaporite minerals or brine 34
FIGURE 9 Map of fluoride distribution in the Buena Vista area 38
FIGURE 10 Dissolved carbon dioxide versus excess silica for ground water in the Buena Vista area 39
FIGURE 11 Subsurface geology and stratigraphic cross section of the hot well area near Buena Vista 41
FIGURE 12 Reconnaissance geologic map of the Buena Vista geo thermal area 43
FIGURE 13 Temperature versus depth profile of deep well east of Buena Vista 47
FIGURE 14 Complete Bouguer gravity map of the Buena Vista area showing areas with copper mineralization 48
FIGURE 15 Reconnaissance geologic map of the Cactus Flat-Artesia area 51
FIGURE 16 Bouguer gravity map of the Safford-San Simon Basin (pocket)
FIGURE 17 Aeromagnetic map of the Safford-San Simon Basin (pocket)
FIGURE 18 Location map of Dipole-Dipole electrical resistivity profiles 7 and 8 54
iv FIGURES
PAGE
FIGURE 19 Subsurface resistivity models and pseudosections of resistivity profiles 7 and 8 55
FIGURE 20 Temperature versus depth well data in the Cactus Flat-Artesia area 57
FIGURE 21 Map showing the area of high temperature gradients in the Artesia area. 58
FIGURE 22 Map showing distribution of soil mercury in the Cactus- Flat Artesia area 60
FIGURE 23 Anion ratios versus lithium in Cactus Flat-Artesia area ground water 62
FIGURE 24 Dissolved carbon dioxide versus excess silica in Cactus Flat-Artesia area ground water 66
FIGURE 25 Temperature versus depth data for artesian wells in the San Simon area 70
FIGURE 26 Structure contour map of the base of the blue clay unit in San Simon area 72
FIGURE 27 Structure contour map of the top of the blue clay unit in the San Simon area 73
FIGURE 28 Map of water level of artesian wells in the San Simon area in 1915 75
FIGURE 29 Estimated temperature gradients of artesian wells in the San Simon area in 1915, 76
FIGURE 30 Map showing distribution of Na-K-Ca geothermometer tem- peratures in the Bowie area 80
FIGURE 31 A gravity subsurface model of the Bowie area 81
FIGURE 32 Bouguer gravity map of Bowie area compared to locations of ground-water falls 82
FIGURE 33 Topographic profiles across the San Simon Valley 83
FIGURE 34 Map of water table in the Bowie area in 1975 84
v TABLES
P~E
TABLE 1 Wells with measured temperatures greater than 30oC in the Safford-San Simon Basin, Arizona 89
TABLE 2 Chemical analysis of ground waters in the Safford-San Simon area. 94-103
2A Analyses of Gila Valley-Indian Hot Springs ground waters 95
2B Analyses of Buena Vista area ground waters 96
2C Analyses of Cactus Flat-Artesia area ground waters 98
2D Analyses of San Simon area ground waters 100
2E Analyses of Bowie area ground waters WI
2F Analyses of Whitlock Mountains area ground water W2
TABLE 3 Silica and Na-K-Ca geothermometers for ground water in the Safford-San Simon area. 103-108
3A Geothermometers for the Gila Valley-Indian Hot Springs area. 103
3B Geothermometers for the Buena Vista area W4
3C Geothermometers for the Cactus Flat-Artesia area 105
3D Geothermometers for the San Simon area 106
3E Geothermometers for the Bowie area 107
3F Geothermometers for the Whitlock Mountains area W8
TABLE 4 Summary table showing aquifers in the Cactus Flat area with temperatures and estimated temperature gradients 109
vi APPENDICES
PAGE
APPENDIX 1 Selected:dri11ers logs 110-114
APPENDIX 2 pH correction of dissolved silica 115-118
APPENDIX 3 Arizona Bureau of Mines Memorandum on the Funk 119-120 Benevolent No. 1 Fee well near San Simon
vii INTRODUCTION o In the Safford-San Simon Basin, thermal water (>30 C) flows from numerous
artesian wells and springs. These wells and springs are used by several min-
eral baths in the Safford area. The most notable hot water occurrence in the
area is Indian Hot Springs located northwest of Safford near Fort Thomas.
Nearly all wells deeper than 200 meters in the Safford area flow naturally o and have discharge temperatures greater than 30 C. Deepest of these wells,
the 1,148 m Underwriters Syndicate #1 Mack oil and gas test or Mary Mack well
near Pima, is indicative of a substantial low-temperature geothermal resource.
The well is no longer flowing and it is believed that the pressurized water
broke through the shallow and deteriorated casing after the well flow was
temporarily shut-in some years ago. However, in 1933, Knechtel (1938) reports o that this well had an artesian flow of2,500 gpm of 59 C, sodium chloride water
with 2,251 parts per million (ppm) total dissolved solids (TDS).
Figure 1 is a map showing the location of the Safford-San Simon area.
Hot springs and areas with hot wells are also shown. The study area, between
Fort Thomas and San Simon, straddles a valley which is drained by the Gila and
San Simon rivers. The study area is bounded by rugged mountains on the south- west and northeast sides. Topography within the study area is mostly gentle
and easily accessible. Agriculture is mostly confined to the Gila River flood plain between Fort Thomas and San Jose, and along Interstate 10 from Bowie to
San Simon. Important geothermal anomalies occur in all these agricultural areas. Communities in the area are closely situated to the agriculture.
Rising costs and supply problems for hydrocarbon fuels have intensified the need for alternative energy sources. Developing the potential geothermal resources in the Safford-San Simon basin area could reduce energy costs and assure the area of a constant energy supply. Also, new agriculture-related
1
businesses such as food processing, grain drying or ethanol production using
geothermal energy are possible.
This report summarizes the geologic and geohydrologic features important
to the geothermal regime of the Safford-San Simon area. The purpose of the
investigation is to define areas in the Safford-San Simon basin that have
potential geothermal resources suitable for direct use.
Several things are required to make geothermal energy feasible. The most
important requirement is the availability of a suitable geothermal resource.
In order to determine resource suitability for a particular application,
several questions concerning the potential resource need answering before
planning and development can proceed: Is the potential resource beneath land which is favorable for development; or, in other words, what is the land own
ership, topography, and access? What depth is the reservoir? What production
temperatures are likely? What is the chemical quality of the geothermal water? What are the probable reservoir rocks and their reservoir properties?
What are the subsurface geologic controls on the permeability and location of the reservoir? What is the geothermal heat source and the natural heat loss of the potential resource?
Direct-use applications may use geothermal water between 300 C and l800 C.
The chemical quality and production requirements vary depending on the type of utilization and heat requirement.
2 Land Status
Figure 2 shows land ownership in the Safford-San Simon basin, Arizona.
Private or patented lands are found mostly in the flood plain of the Gila
River, in the Cactus Flat-Artesia areas, and along Interstate 10 around the communities of Bowie and San Simon. The U.S. Bureau of Land Management (BLM) administers the bulk of the land in the area. Small tracts of state lands are interspersed with the federally owned (BLM) land. Prospective lands with potential for geothermal resources are both private (patented) and federal.
3 Previous Work
Many studies are available which pertain to the geology in the Safford
San Simon basin area. Co~nty geologic maps published by the Arizona Bureau of Mines (Bureau of Geology and Mineral Technology) provide generalized structural and lithologic information on the area. More detailed geologic information on specific localities within the study area are also published.
Cooper (1959) and Cooper (1960) show the geology of southeastern Cochise
County to include the southern Safford-San Simon basin. Gi11erman (1958) discusses the geology of the Pe1onci110 Mountains which border the east side of the Safford-San Simon basin, south and east of San Simon. Sabins (1957) and Raydon (1952) discuss the geology and stratigraphy of the northern
Chiricahua Mountains. Currently the U.S. Geological Survey is mapping the region in detail as a part of the Silver City AMS 1:250,000 Conterminous
United States Mineral Appraisal Program (CUSMAP).
Tertiary sediments in the Safford area are discussed by Heindl (1958),
Seff (1962), and Harbour (1966), while White (1963) summarizes the Cenozoic stratigraphy around San Simon. Cenozoic volcanism and geochronology of the
Safford area is outlined by Berry (1976) and Strangway and others (1976).
Deal and others (1978) discuss the Cenozoic volcanic stratigraphy and vol cano-tectonic features in the southern Pe1onci11o Mountains. Extensive ash flow tuff sheets and an inferred Tertiary cauldron in the Chiricahua Moun tains are discussed by Marjaniemi (1968).
Several geophysical surveys covering the Safford-San Simon basin are available. Most recently, Wynn and Dansereau (1979) and Wynn (1981) pub lished complete Bouguer gravity maps of the Silver City 1:250,000AMS sheet.
These maps of the study area were done in conjunction with the CUSMAP studies of the U.S. Geological Survey. Aeromagnetic maps of the Safford-San Simon
4 basin are published in Andreasen and Galot (1966) and Sauck and Sumner (1970).
Geohydrology of the area is discussed by Schwennesen (1917), Knechtel
(1938) and White (1963). Preliminary studies of the geothermal resource potential of the Safford-San Simon basin are in Gerlach and others (1975),
Swanberg and others (1977), and Witcher (1979).
Other studies pertaining to the geology in this area are listed in the bibliography at the back of this report.
5 Regional Setting
The Safford-San Simon basin lies in the Mexican Highland section of the
Basin and Range province in southeastern Arizona (Figure 3). Overall eleva tion in the Mexican Highland section is high, 941 meters (3,000 feet), rela tive to the Sonoran section of the Basin and Range in southwestern Arizona.
Significant topographic relief also characterizes the Mexican Highland sec tion. In the Safford-San Simon basin, the Gila and San Simon Rivers have aggraded deeply into Pliocene sediments. The entrenchment of the streams is suggestive of either uplift of the region relative to the Sonoran Desert section or indicative of newly acquired through-flowing status of the Gila
River into the lower Sonoran Desert section of southwestern Arizona.
A zone of seismicity which traverses Arizona from the northwest to south east includes the Mexican Highland section (Sumner, 1976). This seismic activity may indicate continued tectonism. Active tectonism is frequently accompanied by higher crustal heat flow and geothermal phenomenon.
No Quaternary volcanism is identified in the Safford-San Simon basin.
Basaltic Quaternary volcanism does occur in the San Carlos Indian Reservation northwest of the study area, in the San Bernardino Valley south of the study area (Luedke and Smith, 1978) and in the Animas Valley, New Mexico, south east of the study area (Smith, 1978; Reeder, 1957; Luedke and Smith, 1978).
Conductive heat flow studies of the region are published by Reiter and
Shearer, 1979. Shearer (1979) gives additional heat flow data in a New
Mexico Institute of Mining and Technology Ph.D. ~hesis. At present, no heat flow data are available for the southern Safford-San Simon basin.
Reiter and Shearer (1979) used mineral exploration drill holes in the Gila and Peloncillo Mountains to obtain their heat flow estimates. Conductive heat flow in this area ranges between 1.4 HFU and 2.3 HFU with a mean of
6 114° 112° IIOO 108° 106° 104°
NEVADA UTAH COLORADO ARIZONA NEW MEXICO SOUTHER. 36" /Rcfc0 SpUTH,ERN MOUNTAINS ROCK'd I;' / I 36° COLORADO PLATEAU PROVINCE PROVINCE '-10UNTAIf'lS PROVINCE
_FLAGSTAFF
PLAINS ,, PROVINCE I (SACRAMENTO I -1:340 ---J I I "\. ~"nll"" --r- " f I I'~ SECTION' I " -/ I ~ SONORAN -Dl1/'rAllv...... , MOGOLLONDATIL ;,'I, -', rT'V~/r/..1.,---' ' .... _... tI " II I SECTION ~ '"---, ...... , ;',,' \~LATEAU/ fRIO GRANDE \, BASIN AND RANGE SAFFO~ ""'__'./! RIFT : PROVINCE"\,~~ : \ MEXICAN HIGHLAND SECTION I ;,...... , VI/III/IA I :: " 3201- TlIC§ON- } BASIN AND RANGE PROVINCE ~ , ~ f \) J -132° I ,- ----, StUd _"':';,---i:-\-,\\- Y'4 \ N n 50 MILES ! ' area ,If ,\ ...... ,,\f \\ \ "\ \ I \? '------, I MEXICO ' / ,I 114° 112° IIOO 108°
Figure 3. Location map of study area and physiographic provinces. , 1.86 HFU +- .33 HFU. The variation in values is most likely due to upward- or downward-moving water along nearby faults or shear zones (Reiter and Shearer,
1979). The regional conductive heat flow of the study area appears normal for the southern Basin and Range province.
A poorly understood regional feature with potential significance for geothermal exploration in the Safford-San Simon basin is the "Texas Zone" or
"Texas Lineament" (Schmitt, 1966). Texas Zone will be used in this report and refers to a west-northwest oriented belt crossing southern Arizona through the Basin and Range province. The belt is defined by west-northwest to west striking outcrop patterns. Evidence for major west-northwest basement struc- tural flaws is circumstantial in most of the belt. However, in a few areas major west-northwest oriented faults occur along the traces of the elements of the Texas Zone (Lutton, 1958; Titley, 1976; Drewes, 1971; Drewes, 1972; and Swan, 1976). These elements or linear discontinuities have been involved in numerous tectonic and depositional events since Precambrian. Differen- tial uplift and left lateral strike slip are documented along portions of the linear discontinuities. Today, the grain of the Texas Zone is observed in outcrop patterns that are elongated transversely to present landforms (Titley,
1976). Titley (1976) states, "The grain is revealed in at least six present- ly recognized faults or linear discontinuities which border northwest trend- ing blocks of some 30 to 40 kilometers in width. Each block bears its own
"signature" by virtue of unique stratigraphic relationships and by distinctive relationships to adjoining blocks." Figure 4 reproduces Titley's interpre- tive map showing the Mesozoic stratigraphic and tectonic relationships that appear as discontinuities or elements of the Texas Zone. The Texas Zone linear discontinuities may have an origin during Precambrian; and they may be fundamental flaws in the crust of southern Arizona. The Texas Zone discon-
8 .,/ ~~~ ~~ ,/ ~/" ~,~~~ y ~~~/ 0"Y GLE~WOOD \,'5:/ ~ ..~1- ",/ ". ':)~~.,/" v',- ".'. ~
Figure 4. Regional lineaments and crustal discontinuities. tinuities appear to correlate with late Paleozoic and Mesozoic tectonic and sedimentation patterns in southern Arizona (Elston, 1958; McKee, 1951;
Peirce, 1976; Ross, 1973).
In the Safford-San Simon basin, two linear discontinuities are inter preted to cross the study area. The northern element coincides with the south-facing escarpment of the Gila Mountains. This northern element contains a northwest-striking array of Laramide porphyry copper ore bodies and pros pects in the Gila Mountains and Peloncillo Mountains to include the Phelps
Dodge, Kennecott, San Juan and Sanchez ore bodies in the Gila Mountains and the Sol and Slick Rock basin prospects in the northern Peloncillo Mountains.
Another apparent Texas Zone discontinuity crosses the study area from Stock ton Pass in the Pinaleno Mountains to Granite Gap in the Peloncillo Mountains.
A major west-northwest oriented fault zone with Precambrian left-lateral strike-slip traverses the Stockton Pass area (Swan, 1976). In the San Simon area, the southern boundary of a Pliocene-late Miocene depositional basin is on strike with this element. The depositional basin is interpreted from drillers' logs and will be discussed in detail in the discussion of the geothermal potential of the San Simon area. At Granite Gap near the Arizona
New Mexico border a structurally high exposure of pre-Tertiary rocks documents another major northwest-oriented fault zone, which is also on strike with the
Stockton Pass zone (Gillerman, 1958; Armstrong and Silberman, 1974; and
Drewes and Thorman, 1978).
A major northeast-striking feature, the Morenci lineament, crosses the northern Safford-San Simon basin. The Gila River east of Safford defines the lineament where it cuts through the northern Peloncillo Mountains in the
Gila Box. The lineament crosses the Pinaleno Mountains at the "dog leg" in the range. Several very prominent canyons oriented northeast drain the east
10 side of the mountains and coincide with shear zones mapped by Thorman
1981. These shear zones may be elements of the Morenci lineament. The
Morenci lineament appears to be a highly useful exploration concept for geo
thermal resources because every hot spring with a temperature greater than
40 0 C in southeastern Arizona occurs within 20 kilometers of the median of the
lineament trace. Chapin and others (1978) first defined the lineament in a
geothermal and geologic context where it crosses the Rio Grande rift in New
Mexico. The Morenci lineament may be a major crustal flaw.
The significance of the Texas Zone and Morenci lineaments for geothermal resource exploration is important even though these lineaments are based on highly diverse and sometimes sparse geologic data, which can be related in a genetic sense using a somewhat speculative concept--major crustal flaw(s), which localize and intensify faulting and plutonism. Because highly frac tured rock and deep-seated zones allowing magmatic intrusion or deep circu lation of water is of prime importance in the localization of geothermal sys tems, regional delineation of potential zones of highly fractured rock is useful in the evaluation and interpretation of known shallow geothermal mani festations, and exploration for deeper hidden geothermal systems.
11 Regional Stratigraphy and Structure
Several superimposed depositional, erosional and tectonic events have
combined to create a favorable geologic setting for low-to-intermediate tem
perature geothermal reservoirs and convective systems in the Safford-San Simon
basin.
Faulting is capable of creating good vertical permeability for deep cir
culation of water. Also, high-angle faults may displace permeable rocks to
sufficient depth for significant heating by normal heat flow from the earth's
interior. Low-angle faults may displace impermeable rock over permeable rock
creating a "structural trap" reservoir. In addition, low-angle faults in
Arizona are frequently characterized by impermeable zones at or near the
fault plane. These zones may overlie fractured and permeable rock.
Rock geometries resulting from tectonic movement, post and syntectonic
sediment deposition, and erosion may create favorable combinations of poten
tial reservoir rocks and cap rocks to form "stratigraphic traps". Similar
traps may also evolve during volcanism where episodic and changing styles
and compositions of volcanic eruptions result in mud flows and impermeable
tuff overlying permeable volcanic sequences such as fractured basaltic flows
and fractured welded tuffs.
Impermeable "cap rocks" are as important as the occurrence of permeable
rock. With a cap rock or aquiclude, the temperature of a deep reservoir will
remain high because leakage out of the reservoir will occur only along ver
tical fracture zones or faults in limited flows, thus conserving heat.
Deeply penetrating zones of fractured rock in the Precambrian basement may exist in the area. The hypothesized regional crustal discontinuities
of the Texas Zone and the Morenci lineament are possibly due to fault reacti
vation and plutonism of major Precambrian structures. Present-day regional
12 stress fields may dilate some of these structures where they are oriented
favorably.
The Morenci lineament direction correlates with the northeast direction
of major Precambrian structures in Arizona. Oldest of the Precambrian rocks,
the Pinal Schist, is believed to represent major northeast-trending regional
structural deformation (Silver, 1978). Near the trace of the Morenci linea ment in northwest Cochise County, thePinal Schist is highly deformed and forms
a large (40 km) wide "anticlinorium" exhibiting strongly overturned folds
(Silver, 1978). Precambrian granite and granodiorite plutons intrude the
Pinal Schist. Similar intense deformation is seen in the crystalline rock of the Pinaleno Mountains. It should be noted, however, that the Pinaleno
Mountains are a part of a Tertiary "metamorphic core complex" which overprints the Precambrian deformation (Davis and Coney, 1979).
In the Stockton Pass area, Swan (1976) presents geochronologic data that suggests that the Texas Zone features originated between 1,400 m.y. and 1,200 m.y. In Stockton Pass, Swan (1976) maps a wide zone of west-northwest trending faults which left-laterally displace Precambrian diabase intrusions in granitic plutonst Due to tectonic reactivation after 1100 m.y.
Paleozoic rocks are not believed to be widely present in the subsurface in the Safford-San Simon basin because erosion, subsequent to Mesozoic and
Tertiary tectonism, has probably removed these rocks, although isolated and incomplete sections of Paleuzoic rocks may occur. Zenoliths of quartzite
(Cambrian-Ordovician Coronado Sandstone?) are observed in Laramide intrusions in the Gila Mountains (Dunn, 1978). East of the study area, a Mesozoic up lift is centered in the Burro Mountains, New Mexico. Elston (1958) names this post-Permian, pre-late-Cretaceous feature, the Burro uplift. North of
Burro uplift progressively older Paleozoic rocks are observed in outcrop as
13 the uplift is approached. Late Cretaceous sediments are observed unconform
ably overlapping both the Precambrian rocks on the uplift and Paleozoic rocks
on the uplift margins. Due to the widespread cover to Tertiary sediment and
volcanic rocks, the actual extent of the uplift is not known with certainty.
It is believed the uplift trends west-northwest in conformance with the trend
of Mesozoic sedimentation patterns and tectonic features inferred to comprise
elements of the Texas Zone. Figure 5 is a generalized map of the Tertiary
basement in southeast Arizona and southwestern New Mexico. Inspection of
the map shows that the Pinaleno Mountains may be part of a western extension
of the Burro uplift. However, this is not certain because the Pinaleno Moun
tains are not known to expose late Cretaceous sediment unconformably overlying
Precambrian granite. Tertiary low-angle faulting may have tectonically re moved the Paleozoic rocks since the Pinaleno Mountains are a Tertiary "meta morphic core complex" (Davis and Coney, 1979). The geothermal implications
and description of "metamorphic core complex" are discussed later in this
section.
Basement Structure of the Northern Safford-San Simon Basin
The "Laramide" orogeny, 75 m.y. to 50 m.y., involved uplift, volcanism,
intense compressive deformation and plutonism in that order (Coney, 1978;
Shafiqullah and others, 1980). In the northern Safford-San Simon Basin area, the "Laramide" orogeny is recorded in the Gila Mountains. Andesite and fel sic tuff is intruded by small silicic to intermediate composition stocks, which are associated with local porphyry copper deposits. These volcanic and in trusive rocks range in age from 53 to 58 m.y. (Dunn, 1978; Robinson and Cook,
1966; and Livingston and others, 1968). Intense shear zones and dike swarms trending northeast transect these rocks and they are frequently highly al tered and mineralized. Drill holes up to 4,000 feet have failed to reach the
14 -l!W -.l.!!00 _Jl09° 0 0 -34° 134 134 134° lEGEND P~ Precambrian rock undifferentiated pz Paleozoic rock undifferentiated Mz Mesozic rock undifferentiated o .;c() K Cretaceous sediment or volcanics ~ LI "Laramide" Intrusive , ------~'-,,- .... _-- ~ !' .. • " ...... Pz+Mz+P~ I 4J Mcc Tertiary "Metamorphic core ", " ...., '..\...... "" C0 z complex" " ------','.... 0 " \ '.. .!::f "" , '\ '\ '...... -4 , ""._~' '...... ,... Clifton ... ','...... ,\...'-...... + "", -...... , -330 'l' I + ... , +\I I~... " I "'''', ...... _ ... , I I ""'---~ I ..: ",'" \ Safford...... 0 ' .., K+ P-e - ...... Silver City I I (r.... -----...... ', " 0 ...... '-', ~-, " I-' P.c I \ ... , '...... ", Ln I '\ Mee· "'" " I '.. '---," -... --- ... _-~--- ..... , '...... ,J ,_, \ \\ ...-...... - - ? ...... __41'/ ~I " ... .. \ '. ...,'...... "'-- ... .' "'-, \ ...... : P-e "_...... ' ...... , , " '.. ".' ??? ""'- ...... ,,'? '--...... ~.. \. , \.. '.. . .' "'---- '. Tucson " '--', "-~ o ,,)Mcc ", ..._----"' ....~-, ------, .-.---- ...... _-- '--, I ...- ...,------'-••-- -"-~, ? ... " ' .... _-- I Pz+Mz+P-e ... + -32° + + ?
N ,46kilometers I ~IiZed Mop of Tertiary Basement Southeastern jrlZono. I 30 miles -f- I I I 111° 110 0 109°
Figure 5. Map of inferred Tertiary basement lithology in southeastern, Arizona. base of the "Laramide" andesites (Dunn, 1978). Dunn (1978) states that part of the andesite may be a hypabyssal intrusive based upon an apparent grada tional contact with diorite intrusions and the lack of flow or bedding struc ture in the andesite. In any case these fractured intrusions and extrusive rocks penetrate deeply into the crust.
Reservoirs in Precambrian, Mesozoic and Paleocene rocks will occur only in fault and shear zones where these rocks are shattered and permeable. If the shear zones exist in the Precambrian rocks, the Pinaleno Mountains are a potential recharge area at high elevation, which could cause significant forced convective flows of water in the northern and central Safford-San Simon basin.
Post "Laramide" geologic history of the northern and central Safford
San Simon basin began with a period of erosion during Eocene. During this time, most of the late Cretaceous and Paleocene sediments and volcanic rocks were stripped from the surface.
Following Eocene erosion, basaltic andesite volcanism began in the area.
The best studied sequence in .the Gila Mountains is probably representative of the volcanism in the northern Peloncillo Mountains and southern Pinaleno
Mountains. Strangway and others (1976) report 30.2 to 28.8 m.y. K-Ar dates for a reddish brown basaltic andesite unconformably overlying the Laramide andesite. This basal basaltic andesite exhibits amygda1oida1 texture and is in flows one to two meters thick. Flow brecias are very common. Following the lower basaltic andesite extrusion, rhyolites and 1atites were extruded.
One center of rhyo1ite/1atite volcanism was located in the area north of Bryce Mountain and Weber Peak. A large rhyo1ite/1atite dome complex is present (D. Richter, pers. comm.). Phenocrysts are rare in these rocks and in many areas they are extensively autobrecciated.
16 The upper basaltic andesite, overlying the rhyolite/latite flows in the
Gila Mountains, is dark gray and occurs in massive flows two to five meters thick. These rocks are considered equivalent to the 20-25 m.y. Bearwallow .
Mountain basaltic andesites of Elston and others (1973). Contemporaneous with this basaltic andesite volcanism, a large rhyolite/latite dome was extruded in Tollgate Canyon of the northern Peloncillo Mountains ,(D. Richter, pers. comm.). Thin unwelded tuffs from this center of silicic volcanism are quarried for cinder.
Other centers of silicic volcanism are identified at Dry Mountain in the
Whitlock Mountains and in the Peloncillo Mountains northeast of San Simon.
No thick, extensive sequences of welded ash flow tuff are identified in the northern and central areas of the Safford-San Simon Basin; therefore, no large Tertiary, cauldron subsidence features are believed to be present.
Also, no thick sequences of clastic sediment are interbedded in the mid-Ter tiary volcanic sequence that crops out in the mountains bordering northern and central portions of the Safford-San Simon basin. On the whole, the vol canic rocks in the Gila and Peloncillo mountains dip gently northeast and have a total thickness between 0.6 and 1.2 km.
During and after the mid-Tertiary volcanism, the Pinaleno Mountains "meta morphic core complex" probably evolved. "Metamorphic core complexes" may have formed as a result of regional strain, "thermal perturbation, and tec tonic denudation" (Davis and Coney, 1979). Studies show that core complexes in southern Arizona have a four-element morphology (Davis and Coney, 1979):
(1) unmetamorphosed cover rocks are deformed by listric normal faulting, over turned folds, and bedding plane faults; (2) a low-angle decollement zone of erosionally resistant, and frequently chlorititized, mylonitic breccia, mylonite, and microbreccia separates the cover rocks from the metamorphic carapace;
17 (3) a metamorphic carapace displaying highly attenuated greenschist to am
phibolite grade metamorphosed younger Precambrian and Phanerozoic rocks with
"tight iso~linal recumbent-to-overturned intrafolial folds, axial plane
cleavage, boudins, pinch and swell, flattened and stretched pebble metacon
glomerate, lineation and ductile faults" all concordantly plated to the core
rocks; (4) a core of augen gneiss (granitic plutons with sheets of mylonitic
rocks or cataclastically deformed metasedimentary and metavolcanic rocks
(Pinal schist) intruded lit-par-lit by deformed granite or pegmatite layers
(Davis and Coney, 1979). Core rocks contain low-dipping cataclastic folia
tion and a pervasive and systematically aligned mineral and slickenside linea
tion with a low dip (Davis and Coney, 1979). Isotope studies of the pre
Tertiary intrusives of the Catalina metamorphic complex near Tucson reveal
partially or completely reset isotope geochronologic clocks (Damon and others,
1963; and Shafiqullah and others, 1978). Significant thermal perturbation
during mid-Tertiary reset the isotope ratios. This coincides in time with
the voluminous eruption of volcanic tuffs and lavas in southern Arizona.
These volcanic rocks and contemporaneous clastic rocks and underlying Phanero
zoic rocks comprise" the listrically, normal-faulted cover rocks that are al
lochthonous on the core-complex decollement zones. A probable decollement
zone and deformed cover rocks are mapped by Blacet and Miller (1978) on the
west end of the Pinaleno Mountains. At this location, Tertiary volcanic
rocks and mostly volcano-clastic sediment are steeply dipping southeast and
are separated from the gneiss by a low-angle fault or decollement zone.
Steeply dipping and listric, normal-faulted Tertiary volcanic rocks and
possibly "Laramide volcanic" rocks overlie an inferred decollement in the basement of the Safford-San Simon basin on the eastern and northern flanks
of the Pinaleno Mountains. If faulted and fractured "cover rocks" occur
18 over an inferred decollement in the basement of the Safford basin, they may
have significant permeability and have significant geothermal reservoir
potential.
Basement Structure of the Southern Safford-San Simon Basin
The basement stratigraphy and structure in the southern Safford-San
Simon basin has a different character than the basement of the central and
northern portions of the basin. Outcrops in the Dos Cabezas and Chiricahua
Mountains reveal a more varied stratigraphy than is observed in the Pinaleno
Mountains or Gila Hountains.
Two structural terranes typify the northern Chiricahua Mountains (Sabins,
1957; and Drewes, 1976). The northern terrane appears in situ or autoch
thonous. The other terrane is allochthonous and is thrust over the northern
autochthon.
An early Cretaceous gravel, the Glance Conglomerate, unconformably
overlies Paleozoic rocks on the autochthonous block (Sabins, 1957). West of
Apache Pass in the Dos Cabezas, the Glance Conglomerate unconformably overlies
Pennsylvania Horquilla Limestone, while six miles east of Apache Pass, the
Glance Conglomerate overlies the El Paso Formation and Coronado Sandstone
(Sabins, 1957). The Paleozoic sequence overlies Precambrian Pinal Schist, gneiss, and granite.
The allochthonous block, formed by the Fort Bowie and Wood Mountain thrust faults, is correlated on a regional scale by Drewes (1979) as part of an extensive crustal plate thrust northward and northeastward in southeast
Arizona and southwest New Mexico called the Hidalgo Allochthon. In the study area, Drewes (1976) infers a thrust fault in the subsurface beneath the southern San Simon basin, which connects the thrust faults at Granite
Gap with those in the northern Chiricahua Mountains. However, it should be
19 noted that other explanations are proposed for the thrust faults in south
eastern Arizona, which do not require the extensive horizontal movement of
the crust that is implied by Drewes (1976). Jones (1963), Davis (1979) and
Keith and Barrett (1976) present arguments which suggest that the thrust
faults are local and related to the margins of basement cored uplifts.
On the allochthon, the Glance Conglomerate may reach 300 meters thick ness and unconformably overlies only the Pennsylvanian-Permian Naco Group limestones to include the basal Horquilla Limestone. Sabins (1957) pointed out that this unconformity has significant relief. Also, of interest is the apparent Mesozoic erosional thinning of the Paleozoic sequence in a north and eastward direction. The structure inferred by the Glance Conglomerate and thinning of the Paleozoic sequence may indicate a southwestern boundary of the Burro Uplift.
The Dos Cabezas and northern Chiricahua mountains appear to have had significant pre-Rhyolite Canyon Formation tilting. Dips in the Faraway Ranch
0 0 Formation and older Nipper Formation average 20 and 40 , respectively. Tilt
0 ing of the overlying Rhyolite Canyon Formation is less than 10 • Since Far away Ranch Formation appears to thicken toward the south, suggesting a southerly source area, the angular unconformity of the older Faraway Ranch
Formation and the younger Rhyolite Canyon Formation point toward significant volcano-tectonic subsidence or tectonic downwarping to the south. In addi tion, Marjaniemi (1969) postulates that the Rhyolite Canyon tuffs originate from a cauldron centered in the west central Chiricahua Mountains. The
Faraway Ranch Formation ranges 29.0 ± 1.9 m.y. to 28.3 ± 2 m.y. and the Rhyo lite Canyon Formation ranges 25.6 ± 0.8 m.y. to 24.7 ± 0.7 m.y. (Shafiqullah and others, 1978). After subtracting the 30 0 -400 dip attributable to tec tonism during and after volcanism from the observed dips on Paleozoic strata,
20 attitudes of the thrust faults, reverse faults, and Paleozoic rocks are be-
o 0 tween 0 and 35. This means that lower Paleozoic rocks may be preserved
beneath Tertiary volcanic rocks and sediment in the southern Safford-San
Simon Basin in the vicinity of Interstate 10.
Basin and Range
Mid-Tertiary volcanism probably ceased in the Safford-San Simon area by
19 m.y. because the youngest observed volcanism in the area occurred in the northern Peloncillo Mountains 20 m.y. ago. Twenty-million-year-old felsic
lavas and tuffs are observed in Tollgate Canyon and the Gila Box area (Don
Richter, pers. comm.). Post 20 m.y. and contemporaneous with the mid-Tertiary volcanism, coarse clastic rocks were deposited in topographically low areas.
Sediments of this depositional period are observed in the Gila Box at the mouth of Bonita Creek and in Eagle Creek Canyon near Clifton. Heindl (1958) named these sediments the Bonita Beds and Gold Gulch Beds, respectively; and both have basaltic andesite flows and silicic tuffs in basal exposures along canyons. In the Tucson area, the Rillito beds are believed to represent another similar Miocene conglomerate deposit (Pashley, 1966). The Rillito beds are tilted and faulted by normal listric faults and overlie the Catalina fault, the low-angle decollement zone of the Catalina "metamorphic core com plex". Unexposed tilted and faulted Miocene gravels may comprise the base- ment in the Safford-San Simon basin adjacent to the Pinaleno Mountains and may overlie an inferred decollement zone associated with the Pinaleno Moun- tains "metamorphic core complex". The tilted Miocene sediments immediately pre-date Basin and Range faulting.
Present-day basins and ranges began to develop during middle to late
Miocene (15 m.y. to 10 m.y.) $carborough and Peirce, 1978). Scarborough and
Peirce (1978) name this tectonism the "Basin and Range disturbance". The
21 "Basin and Range disturbance" is characterized by complex high-angle faulting
that broke the crust of southern Arizona into a zigzag pattern of horsts
(mountains) and grabens (basins). Valleys of southern Arizona roughly coin
cide with the structural basins; however, the valleys are more extensive due
to erosion of the horsts which have created pediments that laterally extend the low-lying topography. The Safford-San Simon Basin is a manifestation of the "Basin and Range disturbance". Young pediment fault scarps at the
Pinaleno Mountain front suggest that some "Basin and Range" faulting is still occurring at a low ebb. The greatest displacements occurred prior to late
Pliocene because late Pliocene basin-filling sediments are largely underformed by faulting. "Basin and Range disturbance" faulting displaced basement rocks over two kilometers as evidenced by gravity surveys and deep oil and gas drill holes. Erosion of the horst blocks during and after faulting provided detritus to fill the basins with up to two kilometers of clastic sediments.
Actually, the Safford-San Simon basin represents several closely spaced en echelon grabens now buried beneath these sediments to give the impression of one extensive graben.
Integrated drainage developed between basins during Pleistocene time.
The Gila and San Simon rivers have entrenched into the basin-filling sediments, since late Pliocene or early Pleistocene, to complete the present-day physiog raphy within the Safford-San Simon Basin.
"Basin-filling" sediments in the Safford-San Simon basin have been studied by Schwennesen (1917), Knechtel (1938), Heindl (1958), and by Harbour
(1966). While the sediments are continuous in the area, these authors have shown several semi-independent depositional basins. Also, gradation of the sediments from coarse near the mountain fronts to fine near the center of the basins is not a general characteristic of the basin-filling sediments; rather,
22 gradation is observed only in certain localities.
For purposes of definition within the structural framework and geologic history, the "basin-fill" sediments are only those sediments filling the "Basin and Range disturbance" structural basins or overlying post "Basin and Range dis
turbance" erosional pediments. Two categories of basin-filling sediments are evident in this area. The youngest category includes deposits left by rivers and washes, which for the most part are entrenching older basin-fill deposits as a result of post-Pliocene development and integration of through-flowing drainage. In a strict definition,the young category of sediments is not basin fill in that they are sediments in transport out of the basin. The other category of basin sediment is mostly older deposits of internal drainage
(closed basin origin) and are truly basin-filling sediment.
Basin-fill Sediments in the Safford Area
The youngest category of sediments include flood plain deposits of the
Gila River and tributaries and gravel deposits capping "terrace" benches and mesas. The Gila flood plain sediments provide a large portion of the irriga tion water for the Gila Valley.
The older basin sediments are an important factor in geothermal inter pretation of the area for two reasons: (1) they are the reservoir rocks for most presently known occurrences of hot water in the area; (2) they modify the thermal regime of the area because of their low thermal conductivities. The older basin sediments are divided into two geographic distributions for con venience of discussion. The sediments in the Safford area are discussed sep arately from the sediments in the San Simon area. While they do occur in semi,..independent depositional basins, they do have many common characteristics.
In the Safford area, Harbour (1966) informally classifies the basin-fill sediments into two stratigraphic units, upper basin fill and lower basin fill.
23 Harbour (1966) further proposes that the Pliocene-Pleistocene boundary coin
cides roughly with the transition from lower basin fill to upper basin fill.
The stratigraphic transition marks an overall change in the sedimentation pro
cesses which is inferred to be caused by a climatic change. The stratigraphy
change also occurs below the Blancan-Irvington vertebrate faunal transition
(Harbour, 1966).
Harbour (1966) further subdivides the upper and lower basin-fill strati
graphic units into facies. The facies are lithologically and depositionally
distinct but interfinger both laterally and vertically due to rapid changes
in depositional environments.
The lower basin fill is divided into four major facies and two minor
facies. A basal conglomerate facies is in depositional contact with pre-
"Basin and Rangedisturbance'basement rocks. The coarse nature and thickening
of the basal conglomerate facies toward the axis of the northern Safford-
San Simon basin suggest deposition after or contemporaneous with "Basin and
Range" faulting. Harbour (1966) reports that a well drilled for water by
Kennecott Copper Corporation north of Safford intersects 59 meters of conglom
erate before encountering volcanic rocks at the base of the Gila Mountains; while near the Safford airport, another well encounters 123.4 meters of gravel
consisting of clasts of basalt and andesite before entering volcanic bedrock.
A driller's log of another Kennecott well, WW2, north of Safford (exact loca
tion not known) shows 0-36m gravel, 36-273m clay, 273-339m gravel, 339-356m
clay and 356m bedrock (volcanic rocks) (files, City of Safford). In this water well, 66m of the basal conglomerate facies lie beneath 238m of clay and
separated from bedrock by a thin strata of clay. At Safford, the driller's
log of the southern Pacific well documents "blue" clay and gypsiferous clay
24 to depth of 555 meters (Knechtel, 1938). No comglomerate was encountered at
depth in this well. However, in the Mary Mack well at Pima, Harbour (1966)
interprets the basal conglomerate at 442 to 1,148 meters. A driller's log of the basal conglomerate facies in the Mary Mack well shows red sand inter bedded with shale and gravel. Pre-"Basin and Range" rocks (bedrock) are not believed to have been encountered by this well because deep sediments en countered by this well produced copious quantities of water, suggestive of poorly indurated and permeable sediment. The finer-grained lithology of these sediments may indicate deposition in the axis of the basin.
The driller's log of the Southern Pacific well at Safford reported by
Knechtel (1938) is interpreted by Harbour (1966) to show the evaporite facies and the green clay facies of the lower basin-fill stratigraphic unit. Be tween 213 and 555 meters of yellow gypsiferous clay and salty clay are clas sified in an evaporite facies. South of Safford, another Southern Pacific well at Tanque encountered gypsum and clay at a depth of 180 meters. The bottom 10 meters is in gypsum (Knechtel, 1938). Harbour (1966) interprets these sediments as the evaporite facies. Green clay overlies the gypsiferous deposits in both wells and is called "blue clay" by the local drillers.
Where green clay facies outcrops in the Safford area, it shows conformable thin bedded or laminated green and yellow clay layers with sharp contacts.
Northwest of Safford the green clay facies becomes coarser, with alternating red and green clay layers that become increasingly red, silty, and sandy.
The red silt and sand interbedded with red and brown clay is the red facies of Harbour (1966). The red facies overlies the basal conglomerate in the
Mary Mack well. Both the red facies and green clay facies appear to grade into each other and into the evaporite facies towards the center of the dep ositional basin. The basal conglomerate probably intertongues with the
25 evaporite facies and green clay/red facies at their bases and on their margins.
The center of basin-fill deposition appears to be at Safford because the Southern Pacific well at Safford has the greatest thickness and deepest known occurrence of clay and evaporite deposits in the basin. Note, however, that the Southern Pacific well at Tanque encounters gypsum a couple of hundred feet higher in elevation than the well at Safford. This might indicate a separate depositional basin or that the center of the depositional basin is south of Safford in the vicinity of Tanque.
Two subfacies are identified by Harbour (1966) in the green clay facies.
Near San Jose northeast of Safford, a sequence of well sorted .and crossbedded sandstone interbedded with rounded gravel clasts intertongues into the green clay facies. Harbour (1966) interprets these sediments as deltaic deposits.
These sediments are called the delta facies, and they are confined to the area east and north of San Jose.
The other subfacies occurs in discontinuous exposures at the top of the green facies and is called the calcareous facies. The calcareous facies con sists of calcareous zones and thin oolitic limestones or gypsiferous, salty, limonitic, clayey-siltstone interbedded in yellow or green clay. Harbour
(1966) believes the calcareous facies represents the dessication (drying up) of the lake(s) that provided the depositional environment for the green clay facies and evaporite facies. The calcareous facies is not present everywhere due to probable erosion prior to deposition of the dominantly coarse-grained upper basin fill stratigraphic unit. The upper basin fill disconformably over lies the green clay facies. The upper basin-fill stratigraphic unit will not be discussed in detail because its position precludes any potential as a geo thermal reservoir. The upper b.asin-fill stratigraphic unit occurs mostly on basin margins and on the basin pediments where it probably grades into the
26 basal conglomerate facies of the lower basin fill. rfuere this occurs, im
portant hydrologic connection no doubt exists to provide the ground water
recharge and give the observed artesian pressure in the basal conglomerate
facies.
Basin-fill Sediments in the San Simon Area
White (1963) uses an informal two-fold classification for sediments in
the San Simon area. Basin-filling sediment are divided into younger alluvial
fill and older alluvial fill.
The younger alluvial fill category is restricted to sediment deposited
by present-day washes or gravel-capping terraces or remnant erosional features.
Technically, the younger alluvial fill category sediments are not basin-filling
sediments because they are sediments in transport out of the basin.
True basin-filling sediments would be categorized by White (1963) as the
older alluvial fill sediments. White (1963) breaks the older alluvial fill
sediments into four groups: (1) lower unit, (2) blue clay unit, (3) upper
unit, (4) marginal zone. The lower unit is continuous throughout the basin
and probably correlates with the basal conglomerate facies of Harbour (1966)
in the Safford area. Sand, gravel and clay comprise the lower unit and it
contains water under artesian pressure which is tapped locally for irrigation.
Total thickness of the lower unit varies, a maximum thickness of over 610 meters is observed in the depositional basin center.
The blue clay unit overlies the lower unit and attains a maximum thick ness of 183 meters. Correlation of the blue clay unit with the green clay
facies is probable because both "formation" tops occur near the same eleva
tion and have similar deposition setting. Also, the lithology of the green
clay facies and the blue clay unit is apparently identical.
27 The upper unit sediments overlie the blue clay unit and consist of 20 to 60 meters of silt, sand, and gravel. These sediments probably correlate with the upper basin fill unit of Harbour (1966). The marginal unit of White
(1963) is defined as sediments occurring on the basin margins beyond the blue clay pinchout. Marginal unit sediments include both upper and lower unit sediments.
For geothermal purposes, the green clay facies or blue clay units are very important because they are aquicludes and have low thermal conductiv ities. Thus, relatively high temperature gradients and confined aquifers result. The basal conglomerate facies or lower unit sediments provide ar tesian aquifers beneath the green clay facies. Nearly all wells penetrating the basal conglomerate facies or lower unit produce useable quantities of water.
28 Indian Hot Springs-Gila Valley
Introduction
Indian Hot Springs, 4S to 48°C, discharge from basin-fill sediments on the first major terrace above the present-day flood plain and north of the
Gila River. Travertine (calcium carbonate) deposits are observed cementing sediments at many springs discharges. Total flow rate of five spring dis- charges is approximately 1,000 l/min (Mariner and others, 1977).
Geochemistry
Minor amounts of gas, mainly nitrogen, are released at spring orifices
(Mariner and others, 1977). Springs that evolve nitrogen gas are generally associated with lower temperature geothermal systems «ISOoC) (Bodvarsson,
1964; Ellis and Mahon, 1977). Total dissolved solids (TDS) of the Indian Hot
Springs ranges from 2,S70 to 3,004 mg/l (Table 2). Indian Hot Springs have sodium chloride composition with fluoride contents between 2.8 and 4.8 mg/l.
The presence of sulfate, up to IS milliequivalent percent total anions, sug- gests that these waters have had contact with gypsum. An artesian well, drilled to 183 meters at the springs in 1933, had a reported discharge of o lS6 gpm and a temperature of 48.30 C (Knechtel, 1938). Using a MAT of 18 C, an estimated temperature gradient for the well at Indian Hot Springs is l6SoC/km. This gradient is much higher than average temperature gradients
(46-48°C/km) of wells in the Safford-San Simon basin. The high temperature gradient indicates that the well intersects the zone of upward-flowing water, which discharges at the surface as spring flow.
Structure
Due to the mantle of travertine-cemented sediment and soil cover, no exposures were available to identify probable structures which control spring
29 R27E
T5S. T5S.
T6S. T6S
T7S. T7S.
T8S T8S.
T9S.
TIOS. TIOS.
Figure 6. Major geologic structure in the Safford area.
30 flow. A fault zone(s) is inferred to provide the vertical conduit for ther
mal water flow at Indian Hot Springs.
Projection of the NNW-striking Pleistocene zone of faults in the Cactus
Flat-Artesia area across the Indian Hot Springs location is possible. The
springs are on strike with the Cactus Flat fault zone; and the Gila River
changes course to conform with the inferred trace of this fault zone (Figure
~. In addition, Muller (1973) shows degradation of chemical quality in
shallow wells «6Sm) which are downstream from the inferred trace of the Cac
tus Flat zone. Sodium chloride water may leak upward along the fault and
flow into shallow floodplain aquifers.
Another fault, crossing the Indian Hot Springs area, is inferred from
gravity data and from geologic investigations at Big Springs.
Big Springs, east of Indian Hot Springs in D-6-2S-S, is centered on a
WNW alignment of springs. Deformation of basin-fill sediments is observed
in arroyo walls just below Big Springs. Laminated clay deposits (green clay
facies) are tilted and faulted. Mud intrusions along shears and faults sug gest liquification during deformation. This deformation is pre-ancestral Gila
River gravels, which are in angular unconformable contact with underlying o deformed basin-fill sediment. Faults are oriented N2S W and show downward displacement to the north. This exposure is interpreted by the writer as antithetic deformation on the hanging wall of a large unexposed normal fault which may control spring alignment. The spring alignment at Big Springs can be projected northwest through Eden Spring and across Indian Hot Springs.
Apparently, Indian Hot Springs are controlled by a fault(s) which allows vertical flow out of deep «1 km) artesian aquifers.
At least two deep wells in the area, the Mary Mack well and the Mount
31 Graham Mineral Bath well, discharge sodium chloride water with cation and
anion ratios similar to Indian Hot Springs. Temperatures of water produced
by the artesian wells are all within 110C of Indian Hot Springs (48oC). The
1,148-meter Mary Mack well, D-6-24-l3AB encountered five water-producing 0 zones below 495 meters; and the well discharged 2,250 gpm of 58.9 C water,
which had a sodium chloride composition and 3,530 mg/l TDS (Knechtel, 1938)
(see driller's log in appendix 2).
The Mount Graham Mineral Bath well, D-6-25-36CBB, discharges 610 gpm o (files, USGS, Tucson) 46 C, sodium chloride water with a TDS ranging from
4,431 to 8,292 mg/l. This well, formerly called the Smithville Canal well,
was drilled in 1957 to a total depth of 659 meters. Lithology in the well
is mudstone to 312 meters depth (green clay of Harbour (1966), gypsiferous
siltstone/mudstone and gypsum from 312 to 488 meters depth (evaporite facies
of Harbour, 1966) and "volcanic" sand from 488 to 659 meters depth (basal
conglomerate of Harbour, 1966) (files, USGS, Tucson). All water flow in this well apparently enters the borehole below 488 meters depth.
A rather large and extensive low-temperature (40 to 70oC) geothermal
reservoir is indicated in the Gila Valley by the deep wells and the hot
springs. Near the Gila River, the top of the reservoir is approximately 500 meters deep and may reach to 1 km in depth. The reservoir probably extends
in the subsurface from Thatcher to Fort Thomas. Continuation of the reser voir beneath Safford is possible; however, the reservoir depth is probably much greater than 500 meters. A schlumberger resistivity sounding (Figure 7) centered in D-8-26-2C and modeled as a three-layer earth, shows 219 meters of
6.5 ohm-meter rock (Probably the green clay facies of Harbour, 1966) and 853 meters of 0.5 ohm-meter rock (probably the evaporite facies of Harbour, 1966, and/or possibly sand and gravel containing thermal, saline water) (Phoenix,
32 DWG. NO.-R.-IJ.-~
STATE OF ARIZONA BUREAU OF CALCULATED THICKNE8S AND RE81STlVITY GEOLOGY a MINERAL TECHNOLOGY
THleICNES. REIISTIVITY GEOLOGICAL SURVEY BRANCH IN ..ETERS I-OHII METERS I i GEOTHERMAL GROUP 219.0 I 6.6 SAFFORD VALLEY GRAHAM COUNTY, ARIZONA
863.0 I .6
DEPTH SOUNDING
.. C>o 97.0 I:i 10 C'1 I;; .. C'1 ""I .0 ~ ~ .. FREQUENCY: 0.126 HZ. APP~VED: /;)«- J. ."<..
DATE SURVEYED: JUNE 1979 DATE: ''I-'tl <" l'
PHOENIX GEOPHYSICS All/I FEEr • •• '0 .. ,- 1000 1000 40ClD 10oo SCHLUMBERGER DEPTH SOUNDINGS
Figure 1 Schlumberger resistivity profile near Safford. N+ SCAL.E o 15 Kilometers I E3 F3 Fa
BASE MAP:USGS Sliver City, 1:250,000
Figure, 8. Map showing areas with low electrical resistivity and wells which encounter evaporite minerals or brine.
34 Geophysics, 1979). Nearby at Safford, the Southern Pacific well bottomed
at 555 meters in gypsiferous sediment. Another nearby deep test well, D-7-
26-26ABA, bottomed in halite and mudstone at 689 meters. These well data
indicate that a potential geothermal reservoir at Safford is deep, possibly
between 800 meters and 1 kilometer. Temperatures between 55 and 70 0 C are
possible, based upon an indicated temperature gradient of 45oC/km.
Geothermometry
Application of chemical geothermometry on these waters is not appro-
priate within the qualifying assumptions required for their use (Fournier
and others, 1974). Because these waters are probably in contact with highly
soluble evaporite minerals, the Na-K-Ca geothermometer estimates are not believed to reflect deep reservoir conditions. Silica is in equilibrium with a1pha-cristobalite at Indian Hot Springs. Silica concentrations in the
Mount Graham Mineral Bath well are super-saturated with respect to all solid species of silica except amorphous silica (opal). Alpha-cristobalite geo
thermometers of the Mount Graham Mineral Bath well are 56°C to 64°C.
Conclusion
The thermal regime of the Gila Valley is believed generally conductive, with systematic temperature increases with depth except near fault zones.
The heat source for the thermal waters is easily explained by the normal flow of heat from the earth's interior in the region. The relatively high o temperature gradients (>40 C/km) in this area are probably due to the insu- lating affect of low heat-conductive, basin-filling sediments.
Figure 8 is a map of subsurface resistivity obtained by dipole-dipole profiling. This map is useful to show the subsurface extent of gypsi- ferous clay and evaporite minerals. Wells drilled in the zone of low resis- tivity are likely to encounter water whose TDS exceeds 3,000 mg/l. Localized
35 aquifers in these areas may have brines with TDS over 100,000 mg/l. A deep abandoned well at the Safford Golf Course encountered brine. Water produc tion from depths below 1.3 kilometers is untested in the Gila Valley.
36 Buena Vista Area
Introduction
More than eight irrigation wells, which are all less than 213 meters deep, discharge thermal water from 30 to 49 0 C. These thermal waters, pre viously reported by Muller and. others (1973) as the "Larson anomaly", have sodium chloride-sulfate chemistry with TDS less than 1,200 mg/1 (Table 2).
Three of these wells sampled during the study have artesian flows which ex ceed an estimated 100 gpm during the winter months. Pumped flow rates measured by the U.S. Geological Survey range between 900 and 1,600 gpm (files,
USGS, Tucson).
Geochemistry
Thermal waters in the Buena Vista area are readily distinguished from local non-thermal waters by their low calcium «20 mg/1) and magnesium
«8.0 mg/1) concentration and their high fluoride (>4.0 mg/1) concentrations.
Fluoride concentration up to 14.0 mg/1 are reported for thermal waters in this area (Figure 9). Dissolved silica in these thermal waters is super saturated with respect to quartz and chalcedony at measured discharge tem peratures. Dissolution of alumino-silicate minerals is tentatively suggested as the primary control of dissolved silica because the highest silica concen trations are observed in waters with the highest dissolved carbon dioxide concentration (Figure 10). Carbon dioxide reacts with sodium and potassium feldspars to form clay while adding dissolved sodium, potassium and silica to ground water (Garrels and Mackenzie, 1967; Stumm and Morgan, 1970).
Subsurface mixing of non-thermal waters and thermal waters may occur because Muller and others (1973, p. 55) report a conversation with Mr. Moroni
Larson of Solomonsvi11e, who states that wells on the "east side of the road
(San Jose Road) gradually cooled after pumping." This cooling suggests that
37 "-"h.~" LR26E1F!27E,/; "..,,'; ~~/ ~ ~"( 'I .....-.. . / ;;,' : . I_ 36° t·~ \' ,~~/ -1/0'0 3 / }, • f 35 ~3l-- / J; j>"
JI)"
,- '~~'~
, ,
I ~"J' co ~.,., C')
.. I :: #~-;;:ff"1~ I ,1/"0 I IlM~'~ ~~F'i~~C' Ii ; I -; '18M I t ~ 29S~, ,~t/>0/<1 , I "3097, I . - I' , :4..... ~l ";"fIt>I.SdI n ( IBM 2970) 2,976 I'Well""", 19 ___ . 23 l \ iiJ', ~~496 I :~ 24 ' ,.l I 22 I .~~';Ji'4-/--' \' 'I I \" R26E'R27E R27EIR28E '. , ./'
SCALE 1:62,500 I inch equals I mile
Figure 9. Map of fluoride distribution in the Buena Vista area. / I 2 I 1·/
• I.3 I I / Correlation Line of /"'2.. '-__- Cactus Flat-Artesia 1 Wel,. I / I / / / .7 / .10 / • / " .'8 / / / I / / / / / / / / SILICA IN WELLS 5 AND 6 MAY I BE IN EQUILIBRIUM WITH CHALCEDONY / / /
-4.5 +--...:/--....,-----..,.-----r------.,----f -5.0 -4~5 -4~0 -3.5 -3.0
LOG SiCOH)4 EXCESS SILICA
INCREASING ACTIVITY (CONCENTRATION)------_~
Figure 10. Dissolved carbon dioxide versus excess silica for ground water in the Buena Vista area.
39 hydraulic connection exists between the thermal and non-thermal waters.
However, no correlation is apparent among chloride, lithium or boron concen
trations. Systematic change in chloride, lithium and boron would confirm
mixing because the constituents are highly soluble and are probably not in
volved in equilibria reactions that cause mineral precipitates; therefore,
if variations are observed, they are explained by mixing of high concentra
tion thermal water (provided their concentrations are, in fact, high) with low concentration non-thermal water.
Silica and Na-K-Ca geothermometers are calculated for the Buena Vista thermal waters and listed in Table 3. Reliability of the silica geothermom eter temperatures are highly suspect because of probable non-quartz or non chalcedony equilibria control of dissolved silica and, also, because mixing is possible. Likewise, the Na-K-Ca geothermometer is not believed reliable because cation exchange probably occurs among dissolved calcium and sodium contained in clay minerals which occur in basin-fill sediments. In addition, gypsum is possibly present in the basin-fill sediments and probably in the underlying bedrock, which is reported to contain oxidized copper-bearing sul fides in well D-6-27-35CBB (files, USGS, Tucson). Dissolution of gypsum in ground water affects carbonate equilibria because additional calcium is in troduced which may cause calcite to precipitate. In waters where calcite has precipitated, erroneously high geothermometer estimates result due to calcium loss. Where dissolution of gypsum occurs with no attendant calcite precipitation, calcium concentration is increased and erroneously low geo thermometer temperatures are calculated.
Geology and Reservoir Characteristics
Regional heat flow studies, reconnaissance geology and geophysics are used to tentatively infer the location, depth, and reservoir characteristics
40 33 34 31
~:::,:,::,::.~,.:,:.:::.,.:::..:. '" . ...:..••. ~ . .'. 4 Sixto Molina j/ ~. .p '''.S'/'! I-' .:r::':: .:::"./" .:.:.:~:: .. :,.. :; , t "", /..-: Q"$: N " (Sl\il'<9 $, I J \.< ~~~.~,,~? :\.' ./~' .,0' 12 7 ..:' fo'" ()~..c)'; OJO + 0 ~ ~r.," ~O <"~, ,'I'; Old Safford- Cllfllon Highwa SCALE:I:24.000 ° .I .2 .3 .4 .5 .6 .7 .8 .9 10 MILES II ! II ! ! ! I I Figure 11. Subsurface geology and stratigraphic erossection of the hot well area near Buena Vista. of the Buena Vista geothermal system. Drillers' logs of area wells deeper than 60 m show the lithology of the shallow geothermal reservoir at Buena Vista. Figure 11 is a fence diagram constructed from geologic interpretation of drillers' logs listed in Appendix 1. Well D-7-27-llBBB is in mostly sandy clay, clay and sand to 105 m depth. These deposits are correlated with the delta facies of Harbour (1966), which intertongues with the green clay facies three miles west of Buena Vista in outcrops north of the Gila River (Harbour, 1966). The mostly fine-grained delta facies provides an aquiclude over per meable gravels that contain confined thermal water. East of well D-7-27-llBBB, in wells D-7-27-2DBB and D-7-27-2AAA, the delta facies is thinned by 50 m; and it is more coarse grained and is interbedded with 3 to 6 m thick gravel tongues or lenses. The delta facies is not present in wells D-7-27-lBBA, D-7-27-2AAD and D-6-27-36CCC; instead, these wells penetrate permeable gravel and "caliche". The absence of the delta facies is probably caused by pinchout and not by faulting because, north and south of the lithology change in wells D-6-27-35CBB and D-7-27-2CDB, bedrock depths are interpreted from drillers' logs at approximately 213 m. The shallow geothermal reservoir at Buena Vista is in permeable gravel below the delta facies. Top of the reservoir ranges from 105 m depth at the Sanchez Monument to less than 46 m depth 1.4 miles northeast of Sanchez Monument (Figure 12). The base of the shallow reservoir is 213 m depth. The permeable gravels comprising the reservoir are tenta tively correlated with the lower basin fill, red facies or basal conglomerate facies, of Harbour (1966). Thermal water contained in the shallow reservoir may leak upward along buried structure from a deep reservoir. Figure 12 is a reconnaissance geo logic map of the area compiled from available published maps and from aerial U-2 photos and field reconnaissance. A major fault, the Butte fault, crosses 42 GElEIEEOl'3,53IEEa3lljO Mile EXPLANATION RECENT GILA RIVER DEPOSITS AND ARROYO - LATE CRETACEOUS-PALEOCENE (LARAMIDE) E] DEPOSITS INTERMEDIATE VOLCANIC AND INTRlJSIVE ROCKS PLEISTOCENE TO RECENT PEDIMENT. ALLUVIAL FAN AND SLOPE DEPOSITS SCARP IN Qp SEDIMENTS AS DELINEATED B I FROM BLACK AND WHITE AERIAL PHOT(} MID TO LATE PLEISTOCENE ANCESTRAL GILA / GRAPHS. RIVER TERRANCE DEPOSITS MID MIOCENE TO EARLY PLEISTOCENE BASIN INFERRED BURIED "BASIN AND RANGE" FILL SEDIMENTS FAULT ZONE BASED UPON LITHOLOGIC DISCONTINUITY AND BOUGUER GRAVITY TERTIARY BASALTIC VOLCANIC ROCKS DATA. LOCATIONS ONLY APPROXIMATE. BALL ON DOWN THROWN DIRECTION. Figure 12 Reconnaissance geologic map of the Buena Vista geothermal area. 43 the area less than one mile north of the Buena Vista thermal wells. Core de scriptions by E.S. Davidson of the U.S. Geological Survey from well D-6-27-35CBB suggest that this well is very near the fault zone (files, USGS, Tucson). Davidson describes a conglomerate between 171 and 210 m whose bedding dips 300 "from vertical" (files, USGS, Tucson). The bedding orientation is interpreted as either evidence of drag on the hanging wall of the Butte fault zone or talus below a paleo-escarpment. Fanglomerate depositional dip is ruled out because the'observed dip is probably too steep. While conglomerates, predating high angle Basin and Range faulting, commonly have monoclinal geometry in Bonita Creek and in Eagle Creek, both east of Buena Vista, these sediments do not contain red granite clasts. Instead, they are angularly unconformable with overlying flat-bedded conglomerate, which consists of basaltic. and red granite clasts (Heindl, 1958). The younger bimodal gravels are post and syntectonic high-angle Basin and Range faulting such that they fill contemporary struc tural basins. Tilted gravels in D-6-27-35CBB, which contain red granite, are included in the younger suite of sediment that fill contemporary basins; therefore, the apparently anomalous bedding orientation of gravels in D-6-27 35CBB may indicate deformation proximal to a fault, albeit the Butte Fault. Below the tilted gravels in well D-6-27-35CBB, volcanic rock and volcano clastic sediments are encountered at 211 m depth, while at 275 m depth, prob able Laramide andesite is encountered. The andesite is epidotized and mineral ized with copper (files, USGS, Tucson). Another well, 1.5 miles south of D-6-27-35CBB, also is believed to bottom in bedrock. This well, D-7-27-2CDB, reaches "red granite" at 213 m depth (files, USGS, Tucson). This "red granite" is interpreted by the writer as a red stained "Laramide" silicic tuff or a stained quartz monzonite intrusion like those exposed in the Gila Mountains near the Lone Star mine. This "red granite" is not believed to be lithology 44 similar to the Precambrian granite in outcrops at Clifton, a likely source area for the red granite clasts in basin-fill gravels. An alternate interpreta tion explains the "red granite" either as a highly indurated conglomerate with granite clasts or as a granite boulder. These alternate explanations seem more speculative, however, when considering that well D-7-2-2CDB lies astride a Bouguer gravity high which encompasses the areal extent of copper mineralization associated with "Laramide" volcanic rock and stocks (Figure 14 ). In the Safford Basin, six miles west of Buena Vista, well D-7-26-26ABA, bottoms in 670 m of siltstone and mudstone, which are herein correlated with the green clay facies of Harbour (1966) (files, USGS, Tucson). Steep Bouguer gravity gradients between this well and Buena Vista, coupled with the much greater thickness of basin fill in well D-7-26-26AB~suggest a large normal fault zone(s) trending west-northwest (Figures 12 and 13). East of Buena Vista, another fault zone is inferred from surface geology and the lithology log of well D-6-28-3lAAB. This well is in sediment to 165 m at total depth (files, USGS, Tucson). Less than a quarter of a mile east of well D-6-28-3lAAB, Tertiary basaltic andesite is observed at the surface. A normal fault striking north-northeast whose hanging wall is west would ex plain the lithologic incongruity between the well and nearby surface exposures. This inferred fault may intersect the Butte fault zone 1.5 miles southwest of well D-6-28-3lAAB. A photo lineament extends south-southwest from, and on strike with, the inferred fault. Just north of San Jose Wash, a scarp facing northwest and coinciding with the lineament is easily seen in black and white U-2 photographs. Origin of the scarp is speculative; however, ter racing is the stronger explanation because the present-day Gila River flood plain parallels the scarp strike. Detailed surface mapping of this area seems warranted in order to determine if the scarp has a tectonic or ero- 45 sional origin. Geothermal systems are frequently localized by Quaternary or Recent faults. Geologic evidence shows that the thermal well area at Buena Vista over lies a structural bench south of the Gila Mountains and bound by major fault zones on the north, south and east. Approximately 213 m of basin-filling sediments overlie the bench which is mostly composed of "Laramide" volcanic rocks and related intrusions. Nearby in the Gila Mountains, "Laramide" vol canic rocks are highly fractured with numerous northeast-trending shear zones and faults (Dunn, 1978; Robinson and Cook, 1966). These rocks are frequently altered pervasively and mineralized along shear zones (Dunn, 1978; Robinson and Cook, 1960). If the Laramide rocks underlying the structural bench are similarly fractured and sheared, which is an inescapable conclusion considering that the area lies astride the intersection of the Morenci lineament and a linear discontinuity of the Texas Zone, a deep geothermal reservoir possibly underlies the structural bench (Figure 6). The Butte fault and the San Jose fault zones may also contain a deep geothermal reservoir,especially near their intersection. A third possible thermal water source for the shallow reservoir at Buena Vista is the Safford Basin. Thermal water may migrate up ward from the basin interior through the basal conglomerate and into sediments marginal to the basin such as those at Buena Vista. In this case hydraulic connection is required between the gravels deeply buried in the basin with sediments on the structural bench. If these later conditions exist, the necessity of a deep and leaky bedrock reservoir in the structural bench or fault zones is not required and the maximum geothermal reservoir temperature at Buena Vista probably will not exceed 550 C. Reiter and Shearer, 1979, discuss the thermal regime of a deep well 3.5 miles east of Buena Vista. A heat flow of five HFU is reported for the 300- 46 100 + + + + + 300 + + + + 500 ~ + + + :I: + l + ll. UJ + o 700- + + + + + 900 - Temperature log from Reiter and Shearer, 1979 ++. :or ++ ++ 1060 I 35.0 50.00 65.0 TEMPERATURE °C >J'igure 13. Temperature versus depth profile of deep well east of Buena Vista. 47 COMPLETE BOUGUER GRAVITY ANOMALY MAP OF THE BUENA VISTA GEOTHERMAL REGION R26E R27E R28E T!5S T6S T7S R26E R27E R28E + SCALE 1:250,000 N o 5MILES E3 E3 E3 I o 5 KILOMETERS E3 F3 F3 EXPLANATION --I!50- X 2.5 Milligcl Contour interval Copper mineralization asso- [2J ciated with Late Cretaceous Bedrock (Pre Late-Miocene Eocene (Laramide) volcanic rock) rocks and intrusions SOURCES Gravity data from Wynn, 1981. Base map: USGS Silver City, I: 250,OOOj /970. Figure 14. Complete Bouguer gravity map of the Buena Vista area showing areas with copper mineralization. 48 500 m interval, while 1.2 HFU is reported for the 950 to 1,050 m interval in this hole (Reiter and Shearer, 1979). The temperature-versus-depth profile of this well (Figure 13) shows a temperature inversion below 500 m which is consistent with the heat flow data. Lateral flow of thermal water entering the drill hole at about 600 m is a possible explanation for the temperature profile below 500 m. The "Laramide" rocks believed to be encountered in this hole are inferred to have fracture permeability and have potential as a deep o geotherma1 reserV01r.'Th'1S we11,whose b0ttom hIt0 e emperature 1S . about 7Z C, implies that the thermal anomaly associated with the Buena Vista thermal wells is more extensive and includes a larger area than is encompassed by the wells at Buena Vista. Available information points toward a deep geothermal system in the fractured and sheared "Laramide" volcanic sequence and in the major Basin and Range fault zones transecting the subsurface in the Buena Vista area. Because no Quaternary volcanism is known in the Buena Vista region, the origin of the thermal anomaly is probably deep circulation of water through hot rock at depth which is heated by regional crustal heat flux. Additional geochemical and detailed heat flow studies are needed to adequately assess the extent and temperatures of the inferred, deep (1 to 2 km) geothermal system in the Buena Vista area. The known shallow, low-temperature geothermal reservoir at Buena Vista area has significant direct-use potential in agriculture, aquaculture, 0 and space heating using 40 to 50 C water. 49 Cactus Flat-Artesia Area Geology Figure 15 is a geologic map of the Cactus Flat-Artesia area. The Pinaleno Mountains, composed mainly of gneiss, form the western boundary of the Safford Basin. Physiographically, these mountains form a steep escarp ment cut deeply by several northeast-striking canyons which follow easily eroded shear zones. These shear zones may allow significant ground water recharge and enhance potential for forced convection in the adjacent basin. During mapping of basin-fill sediments and surficial deposits, several small pediment scarps transverse to drainage and parallel to the mountain front were observed. Subsequent studies by Chris Menges (person. corom., 1980) have documented shearing in the Cenozoic basin fill exposed in an arroyo north of Marijilda Canyon adjacent to and on strike with one of the mapped scarps. It is believed these scarps represent at least one Pleistocene faulting episode. In this area, gravel caps of various ages cover Cenozoic basin fill and form the pediment surfaces. The surfaces displaced by faulting may be mid-to-late Pleistocene age, judging from their soil and caliche development (Morrison and Menges, 1981). Recent and probable late Pleistocene gravel caps do not have scarps. Because the scarps are related to Pleistocene tectonism, they may have an important bearing on the location of the areas with greatest geo thermal energy potential. Pleistocene faults are frequently associated with geothermal systems. Apparently young faults provide good vertical permeability for flows of thermal water. Surface mapping of the basin-filling sediments shows that the top of the green clay facies of Harbour (1966) is about 3,340 feet of elevation. Roadcuts along U.S. 666 near Artesia show outcrops of stratified clay and 50 t N I 5 IOMiles \ \ ""1. EXPLANATION Qal ALLUVIUM. NO RED SOIL DEVELOPMENT Qdf BOULDER CONGLOMERATE. DEEPLY WEATHERED GNEISS BOULDERS. QS3 CONGLOMERATE. WEAK CALICIIE DEVELOPMENT. RED SOIL DE- VELOPMENT. SURFACE BOULDERS NOT BURIED IN SOIL. QTs BASIN FILL SEDIMENT. GRADES FROM A SILTY ARKOSIC SAND- STONE WITH GRAVEL LENSES NEAR MOUNTAIN FRONT TO SILT- CONGLOMERATE. MODERATE CALICIIE CEMENT. FORMS GEOMOR- QS2 STONE AND CLAY TOWARD VALLEY AXIS. PHIC SURFACE WITH WELL DEVELOPED RED SOIL. SURFACE BOULDERS MOSTLY BURIED IN SOIL. Gn GNEISS QSl CONGLOMERATE. HIGHLY CEMENTED WITH CALICIIE. FOlUlS OLD- EST AND HIGHEST GEOMORPHIC SURFACE. SURFACE BOULDERS PLEISTOCENE PEDIMENT FAULT SCARP. BALL ON DOWN THROWN ALMOST BURIED IN SOIL. SIDE. Figure 15. Reconnaissance geologic'" map of the Cactus F1at Artesia area. 51 silt. These deposits become more coarse-grained as the mountain front is approached. Drillers' well logs are interpreted to show sands and gravels interfingering in the clay and siltstone. The thermal artesian aquifers in the area are believed to be sand and gravel tongues in the green clay facies of Harbour (1966). Medium- to coarse-grained and weakly stratified sands resmbling grus overlie the green clay facies west of Artesia. Thin, discontinuous lenses of cobble to boulder conglomerate occur in these sediments, which are corre lated with Harbour's pediment facies. West of Metate Peak, these sediments are in contact with'weathered bedrock. Here, the highly weathered gneiss resembles a red saprolite; the feldspars are mostly altered to red clay. The foliation and augen texture of the gneiss is distinguishable and facil itates definition of the contact with the overlying basin fill. Basin fill at Metate Peak is unusually fine-grained considering its position next to the mountain front. However, above these basin-fill sediments, several dis sected deposits of boulder conglomerate consisting of weathered gneiss boul ders occur in the mouths of canyons. It is inferred that these deposits mostly overlie the pediment facies and are remnants of fans. A gross climatic change may be indicated in the change from grus like fan deposits next to the mountain front to the overlying boulder fanglomerate. In any case, it appears that all of these sediments are hydrologically connected and they allow the recharge of water to the gravel and sand tongues in the green clay facies and an inferred, deep, basal conglomerate below the clay deposits. The area's subsurface structure and stratigraphy is further defined by geophysical data. Both gravity and aeromagnetic data (Wynn and Dansereau, 1979; Sauck and Sumner, 1970) show steep gradients between U.S. Highway 666 and the Pinaleno Mountain front (Figures 16 and 17). The steep gradients 52 are interpreted as evidence of a major Basin and Range fault zone. The gradients are caused by density and magnetic susceptibility differences between basin-filling sediments and the crystalline bedrock exposed in the mountains. Dipole-dipole resistivity profiling parallel to the gradient and trans verse to the strike of the gravity and magnetic anomalies was done by Phoenix Geophysics for the Arizona Bureau of Geology and Mineral Technology (ABGMT) in 1979. Location of the profiles is shown in Figure 18. A 2,000-foot electrode spacing was used in the survey and readings taken at a maximum of five-electrode spacing (10,000 ft) in order to obtain resistivity information up to 1 km depth. Additional modeling of these data was done by William Sill of the University of Utah Research Institute (UURI). Basin stratigraphy and structure is interpreted from the resistivity data (Figure 19 ). Very low resistivity, <5 ohm-meter, is seen adjacent to the Safford Basin axis (as defined by gravity data). This low resistivity probably indicates clay, gypsiferous clay, and halite deposits in the green clay facies and evaporite facies of Harbour (1966). Higher resistivities occur in subsurface in the area west of U.S. Highway 666. Here, subsurface resistivities range between 10 and 50 ohm-meters. Water-saturated sand and gravel are inferred. An al ternate interpretation, which is consistent with the gravity data and geology data, is a buried bedrock erosional pediment that is deeply altered and fractured and overlain by water-saturated sands and gravel interbedded with silt and clay. Fracturing inferred in the bedrock would be due to sub-paral lel faulted blocks that step downward into the basin from the mountain block. Temperature Gradients Witcher (1979) used temperature and depth data, reported by Knechtel (1938), for 44 artesian wells in the Cactus Flat-Artesia area, to delineate 53 ;"~,./(~'/' ·~s I:, .' ;~"' ~.' i"l' 1·····;~ r--+--:'-'\j--~3~~~~:::r"----: . '1' V. ,'I . '.'.' ~ '. Wells .i! 1 I '-.'~ 58.3 .'.7. • "I ".1' I, .' ., I "/:: I 12/ 'I "-lfL' aid ...., I '· ~tn i 65;;l 9);:;j 1 10/ 1 11 ~j'''J,,"1~ 1 lJ!~i~~'f~.d~-~~~OZf5" .. t.W'K~~ ;0 . , I",,!'····· '1'.'_..~---- ,,:1'- r";'~' ., f,·.·' / f~~';\'-" ,. ~:" ." -" ," iV'" 6'W .k·· l i i .. ,·, 26 35 ~<"~ ., n IMile I ""'-'------' EXPLANATION • Well with estimated temperature gradient °C/km • Temperature logged well M53 Measured temperature gradient °C/km 'l'/h Area with high estimated temperature gradients Figure 18. Location map of dipole-dipole electrical resisti vity profiles 7 and 8. 54 LINE 7 RESISTIVITY N =2000 FEET, DIPOLE-DIPOLE ELECTRODE CONFIGURATION N lOW 8W 6W 4W 2W 0 2E 4E 6E 8E IOE 12E I PSEUDOSECTION 2 OF 3 APPARENT 4 RESISTIVITY Ohm-meters 5l..-.__--::~---.b,...._-~...... ,I:_____r--_!o_--__:~---_+_---l N lOW 8W 6W 4W I PSEUDOSECTION 2 OF MODEL 3 APPARENT 4 RESISTIVITY 5 Ohm - meters ~ 0 30 20 ~ 10,00 RESISTIVITY ~ 2000 SUBSURFACE 10 ~ 3000 j} MODEL o 2000 Feet '1 4000 I------t Ohm - meters LINE 8 RESISTIVITY N= 2000 FEET, DIPOLE-DIPOLE ELECTRODE CONFIGURATION N lOW 8W 6W 4W2W 0 2E 4E 6E 8E 10E 12E I PSEUDOSECTION 2 OF 3 APPARENT RESISTIVITY 4 Ohm-meters 5 N lOW 8W I PSEUDOSECTION 2 OF MODEL 3 APPARENT 4 RESISTIVITY 5 Ohm - meters ...... 0 20 20 ~ I 10 ~ 1000 """301 r5 RESISTIVITY I 3 L!- ~ 2000 50 30 10 I I 5 I SUBSURFACE I 1 I 0.4 ~ 3000 MODEL ~ 0 2000 FEET ~ 4000 I I I 5 I---j Ohm-meters Figure 19. Subsurface resistivity models and pseudosections of resistivity profiles 7 and 8. 55 subsurface temperatures and depths to zones producing artesian water flow. Temperature gradients were estimated by subtracting mean annual temperature (MAT) from surface discharge temperatures of the wells and dividing this difference by the well depths. By multiplying this quotient by 1,000, an estimated temperature gradient in °C/km is obtained, provided °c is used for temperature and meters is used for well depths. In this area, artesian wells ranging 79 to 400 m depth have surface discharge temperatures ranging 0 o 20 to 36°C and have calculated gradients ranging 29 C/km to over l30 C/km. Histograms shown by Witcher (1979) indicate that most wells have estimated o temperature gradients between 50 and 60 C/km. In order to delineate water-producing intervals, Witcher (1979) reviewed drillers' comments reported by Knechtel (193S) and depths which drillers re ported increases in water flow. These depths are shown in a summary table of these data (Table 4) which clearly shows five different depth intervals that produce artesian water flow. Also evident are similar temperature gradients for wells below 140 m. This suggests a systematic increase in temperature with depth. Conductive heat flow through the basin-fill sediments and their contained aquifers probably causes the observed consistency in gradients. Reinterpretation of the temperature and depth data (Figure 20) confirms the linear change in temperature with depth. When only wells in the Cactus Flat area are used, a correlation of 0.93206 is obtained. The slope or tem perature gradient is 45 0 C/km with an intercept (or surface temperature) of 19.90 C, which is slightly above the MAT (lSoC). Because water will cool during flow to the surface, the actual gradient is probably slightly higher. If cooling effects are accounted, the surface intercept or the correct tem perature-versus-depth graph is closer to the MAT. Anomalously warm wells at 56 0...---..."...------... 10~/(M - 100 -+ + • -+ t+ '1$0 - • • ~.ff + • " • - --- • 200 •• :. • • I ..• • • • • Temperature vs Depth for Artesian Wells 400 In the Cactus Flat-Artesia Area CACTUS FLAT DATA Correlation 0.93206 • Wells in the Cactus Flat Area Slope 44.9 Intercept 19.9 500 + Wells in Sections 32 and 33, 0-8-26 at Artesia 19 20 21 22 23 24 25 26 ZT 28 29 30 31 32 33 34 35 36 Temperature (DC) Figure 20. Temperature versus depth well data in the Cactus Flat-Artesia area. 57 , i. ,- " -, 35 EXPLANATION • 'th estlma, ted temperature gra dIe' nt °C/km • Well WI ed well . 0C/km Temperature IO~~ature grad.ent ture gradients M53 Measured t~mp timated tempera 'i'/ho Area WI'th high es 'n the area of h~g' h temperature gradients Figure 21. Map show~ g ia area. ~n' the Artes 58 Artesia in D-8-26-32 and 33 have estimated temperature gradients over lOOoC!km (Figure 21). No well data is available south of this area. This area may have potential for geothermal resources exceeding 1000C at reasonably drillable depths (1 to 2 km). The high-temperature gradients may indicate a convective geothermal system beneath confining clays. Mercury Soil Survey A mercury soil survey was conducted in the area with high estimated tem perature gradients. Because mercury soil sampling has been shown to be a useful exploration technique to define geothermal anomalies with no surface expression, it is used herein to help define the southern closure of the anomalous temperature gradient anomaly at Artesia. Matlick and Buseck (1975) have used the technique in Long Valley, California, Summer Lake and Klamath Falls, Oregon, with success. In this survey, two soil samples at each location, five to ten feet apart and from five to ten cm depth, were collected in 3x5-inch ziplock plastic bags, sealed and placed in a styrofoam cooler. Consequently, back in the lab, the samples were dried and screened through a -80 stainless steel mesh sieve. Mercury analysis of the sieved fines was done by atomic absorption. No apparent correlation exists between lithologic units and different surficial deposits in the area surveyed. The background mercury concentra tion is 225 parts per billion (ppb) mercury (Hg) ± 99 ppb. This is a rela tively high background concentration, which may reflect the geologic setting of the surveyed area. Unusually high soil mercury contents are defined by values exceeding 303 ppb, which is the statistical mean plus one standard deviation. High concentrations of soil mercury exist south of Artesia and adjacent to the area of high estimated temperature gradients. Two east-northeast- 59 Figure 22. Map showing distribution of soil mercury in the. Cactus Flat-Artesia ?rea. 60 2 trending 1.5 km closures with soil mercury exceeding 350 ppb Hg occur in the anomalous areas (Figure 22). The general configuration of the anomalous zone is trending northwest. This northwest trend corresponds with the geo- physically defined extent of the basin-bounding fault zone and the trend of identified Pleistocene fault scarps to the north and south of the surveyed area. The superposed east-northeast trending mercury anomalies are on strike with shear zones, mapped by Thorman (in press), in the Pinaleno Mountains to the west. The mercury anomalies may indicate a geothermal system in a basement structural intersection and may indicate the southern closure of the hign estimated temperature gradients at Artesia. Ground Water Geochemistry and Geothermometry Ground water in the Cactus Flat-Artesia area is one of three types of chemistry. Shallow non-artesian wells penetrating unconsolidated sand and gravel nearest the Pinaleno Mountains are sodium bicarbonate water, while deeper wells tapping confined aquifers and unconfined aquifers adjacent or east of U.S. Highway 666 discharge sodium chloride-sulfate water. The sodium bicarbonate waters have the lowest temperatures, total dissolved solids (TDS) and fluoride contents; conversely, the sodium chloride-sulfate waters show o temperatures up to 46 C, TDS is between 1,000 milligrams per liter (mg/l) and 9,000 mg/l, and fluoride contents range between 1.0 and 14 mg/l. A third type of water discharges from some shallow artesian wells and has an intermediate sodium sulfate-bicarbonate-chloride composition with TDS less than 2,000 mg/l. o Temperatures of the latter type water range from 28 to 34 C. A possible mechanism for the intermediate composition water is mixing of sodium bicarbonate water with sodium chloride-sulfate water; however, mixing may not be a dominant mechanism because intermediate composition 61 I I 7__ 25 / I / _32 I 12__8 / I 1.5 -10 / 6-_ I "I I /- 31 I I I I I I 1.0 ,.,I I I rtl " _33 -23 0 0 18 ,'-5 (f) u -13 - I '441 I I + + I rtl It_ I 0 0.5 I U u :I: 17 / -II I I C) I I I 9 I I / 0.0 I I I I I I CORRELATION 0.93145 ,I SLOPE 0.628 I INTERCEPT 1.555 I I .016 ·0.5 I I " -15 Concentrations in milliequivalents -1.0 -0.5 0.0 LOG U Figure 23. Anion ratios versus lithium of ground water in Cactus Flat-Artesia area. 62 waters occur in confined or artesian aquifers. Confined aquifers have limited hydrologic connection with underlying or overlying aquifers. Another mecha nism is therefore preferred to explain th~ apparent continuum in ground water chemistry in the Cactus Flat-Artesia area. In order to further delineate ground water chemistry and test for mixing, milliequivalent ratios of anions are compared to lithium concentrations. Chloride, sulfate, and bicarbonate were selected because they represent major constituents in the Cactus Flat-Artesia ground waters; and they are not likely to be involved in ion exchange with clay. Lithium concentration is used as a comparison to the anion ratios because it is not likely to be involved in equilibria reactions due to its high solubility in the presence of chloride. While lithium may be acquired in ground waters by ion exchange, the reverse is unlikely due to its low electron negativity compared to similar-sized ions. The green clay facies and the evaporite facies are geologically inferred as the source of lithium, chloride, and sulfate due to the probable presence of evaporite minerals. Mixing of sodium bicarbonate water with sodium chloride sulfate water is possible; but it is tentatively ruled out because the corre lation of high chloride-sulfate waters with high concentration lithium waters is not observed until the logarithmic concentrations are compared (Figure 23). Mixing generally shows a linear correlation instead of the observed exponen tial relationship. An exponential relationship suggests that equilibria or exchange reactions are responsible for the variation in ground water chemistry. Also, lithium and anion ratios show no correlation to temperature or TDS, which would be expected if mixing were occurring between a deep homogeneous sodium chloride-sulfate water and the shallow sodium bicarbonate water. Because differences in ground water chemistry due to equilibria or ex change reactions are indicated, Na-K-Ca geothermometry on these ground waters 63 may be erroneous. However, silica concentration is frequently used in geo- thermal exploration to infer deep geothermal reservoir temperatures with the assumption that silica concentration in shallow thermal wells and spring waters is derived from leakage of water out of a geothermal reservoir and that the silica concentration has not been diluted by mixing, or that if mixing has occurred, the mixing ratio can be determined in order to calculate silica concentration before mixing (Fournier and others, 1974; Fournier and Truesdell, 1974). The main requirements for silica geothermometry are that silica in solution is determined by temperature-dependent equilibrium with a solid form of silica in the reservoir and that no equilibration occurs after the thermal waters leak from the geothermal reservoir and cool. This latter requirement is reasonable because water flow or leakage rates probably exceed the kinet- ics of quartz equilibria in water at lower temperatures. Because Cactus Flat-Artesia thermal waters originate from confined aqui- fers which are apparently heated in a conductive heat regime, silica concen- trations should be in temperature-dependent equilibrium with either quartz, chalcedony, or alpha-cristobalite. Silica concentrations for ground waters in the Cactus Flat-Artesia area are all supersaturated with respect to quartz at measured temperatures. In addition, inspection of the chemical analyses of Cactus Flat-Artesia ground waters listed in Table 2 shows relatively high concentrations of dissolved silica (up to 50 mg/l) in cold sodium bicarbonate ground waters, which have high bicarbonate concentrations and neutral pH. Several studies of low-tem- perature «50o C) ground waters in contact with felsic rocks or sediment de- rived from these rocks have shown that silica concentration is a function of dissolved carbon dioxide concentration following the reaction in equation 1 (Garrels, 1967; Garrels and MacKenzie, 1967; Paces, 1972). 64 Equation (1) Alumino-silicate + H C0 Cations + HC0 + Si (OH)4 + kaolinite 2 3 3 (solid) (solid) where H C0 CO (g) H29 2 3 = 2 + Si (HO)4 is dissolved silica Comparisons of calculated dissolved carbon dioxide concentrations with silica concentrations in all three types of ground water in the Cactus Flat-Artesia area suggest that a steady-state disequilibrium with alumino-silicates and quartz has a more important influence on silica concentration than does tem- perature-dependent equilibrium with quartz (Figure 24). Calculation of dis- solved carbon dioxide was accomplished using equation (2) from Paces (1972). Equation (2) -log pC0 = pH-log HC0 - 7.689 - (4.22 x lO-3T)- (3.54 x lO-5T2) 2 3 a where T = Temperature C and concentration : activity Silica analyses were corrected for ionization at higher pH because analy- ses report total silica. Silica (Si(OH)4) derived from dissolution of quartz or alumino-silicates dissociates to form SiO (OH);, which at higher pH becomes an important form of dissolved silica. The following equation is used to correct for silica ionization: Equation (3) log Si (OH)4 log Si (OH)4 log Si (OR); corrected analyzed dissociated where log Si (OH); = - 720.15 - 7.3 + pH + log Si (OH)4 273.15 + TOC equation (4) analyzed and concentration ~ activity Equation (4) is derl\Ted in Appendix 2. 65 / / -2.0 / 15· -2.5 • -3.5 / 21 / CORRELATION 0.6998 34• SLOPE 1.5157 INTERCEPT 3,18 .25 / .26 / .1 -4.0 ·27 • 28 .2 / / -4.5-1--...... :.-..-.....,.-----"'T""'------r------r---'" -5.0 -4.5 -4.0 -3.5 -3.0 LOG Si(OH)4 Excess Silica INCREASING ACTIVITY (CONCENTRATlON)I------...... Figure 24. Dissolved carbon dioxide versus excess silica of ground water in Cactus Flat-Artesia area. 66 Silica concentration in Figure 24 is in excess of the concentration predicted by equilibrium at well discharge temperature for solid silica species, quartz, chalcedony or alpha-cristobalite. Excess silica is deter mined by subtracting pH-corrected silica from the largest predicted concen trations of the three species that the pH-corrected concentration exceeds. Silica disequilibrium generally increases with carbon dioxide concentration. Samples 24, 25, and 27 may have equilibrated with chalcedony. These later waters have low pC0 concentrations and high pH. Waters with high carbon 2 dioxide concentrations readily attack alumino-silicate minerals, releasing silica to solution faster than it (dissolved silica) can equilibrate with quartz or chalcedony. The dissolved carbon dioxide content of shallow sodium bicarbonate waters is introduced by meteoric waters whose initial carbon dioxide content is in equilibrium with the atmosphere. Because the artesian ground waters are in contact with gypsum (hence their high sulfate contents) and probably carbonate minerals such as calcite, their dissolved carbon dioxide content may be controlled by carbonate equilibria in a system closed to additional atmospheric carbon dioxide where gypsum and calcite are both available in sufficient quantities for saturation or near saturation to occur. Ion ex change on clay minerals between calcium and sodium may also influence carbo nate equilibria. Meteoric water recharging shallow aquifers near the Pinaleno Mountain front has high carbon dioxide content, which attacks alumino-silicate minerals to form sodium bicarbonate chemistry water and a solid residue (kaolinite). As the ground water flows deeper and outward into the confined aquifers in the green clay facies, evaporite minerals in the clay dissolve to transform the 67 sodium bicarbonate waters into sodium chloride-sulfate water. Since the sodium chloride-sulfate waters may be saturated with gypsum and calcite, the calcium concentration is probably regulated by carbonate equilibria and prob- ably ion exchange with sodium in the clay. Therefore, the Na-K-Ca geother- mometer is useless in this area to predict geothermal potential. Likewise, silica concentration in these ground waters is not controlled by temperature- dependent solution of quartz, but rather by dissolution of alumino-silicate minerals. Therefore, silicageothermometry is not applicable. Conclusion Temperature and depth data for flowing wells in the Cactus Flat-Artesia o area show a background temperature gradient of 45 C/km. Continuation of a 45 0 C/km gradient to 1 km depth may be reasonable because resistivity data in- dicate at least 1 km of clayey and silty basin-fill sediments. Anomalous temperature gradients in D-6-26-32 and 33 may indicate potential o for intermediate-temperature resources (100 to 120 C). Because no well in- formation is available south of this area, the extent of high-temperature gradients can only be inferred. A mercury soil survey in this area suggests the anomaly extends several miles to the south along U.S. Highway 666. In this area, anomalous mercury concentrations are observed, which may indicate mercury gas leakage from a geothermal system. The highest mercury concen- trations occur where geologic evidence points toward major structural inter- sections. Heat flow studies are needed to evaluate the mercury and tempera- ture gradient anomalies. All of this area has considerable potential for direct use of low-temperature geothermal water (30 to lOoC) from wells 150 m to 1.2 km depth. 68 San Simon Introduction The San Simon area lies astride Interstate 10 in the southern Safford- San Simon Basin and includes the small farming and railroad community of San Simon. Prior to extensive ground water withdrawal and attendant water table lowering, the area had numerous thermal artesian wells, which were used for irrigating crops. Because the upper static water table was relatively deep and the means for pumping from this aquifer was not feasible during the early 1900s, deep wells were drilled to tap an artesian aquifer, which was discov- ered during drilling for water by the Southern Pacific Railroad. Schwennessen (1917) studied the geohydrology in this area and published data on these ar- tesian wells. Thermal Regime Schwennessen's data are used to determine the thermal regime of the area prior to extensive ground water withdrawal. Figure 25 is a plot of well depth versus surface discharge temperature of artesian wells reported by Schwennessen (1917). Wells with flow rates less than 10 gpm and an artesian head less than 3 m above the surface are not used. A linear relationship between the well depths and the measured discharge temperatures exists, which has a slope or o temperature gradient of 46.6°C/km. The surface intercept temperature is 18.5 C, o which is close to the mean annual temperature, l7 C. In the San Simon area, these data indicate the general thermal regime of the basin is created by con- ductive flow of heat through the basin-filling sediments. This means that the temperature of the confined aquifers increases systematically with depth. 69 AVERAGE TEMPERATURE GRADIENT OF THE SAN 1000 , SIMON AREA USING ARTESIAN WELL DATA FROM \ SCHWENNESEN, 1917 AND ASSUMING DISCHARGE •\ ,TEMPERATURE IS BOTTOM HOLE TEMPERATURE ,, en -a: • • w I W ~ • -..J • W > W .. ..J • « • w900en • w >o «aJ J: Ia. w c • • Slope 46.6 °C/km Sea level temperature 70.44°C , Approximate surface temperature IS.5°C (3650" Mean annual temperature I'ZO° C " COffe/ation QS2527 , ·Well with flow rate greater than 10 gpm " and head greater tt,an 10 feet. \ \ \ 800 \ \ 22 23 24 25 26 27 28 29 30 31 32 33 34 35 TEMPERATURE (OC) Figure 25. Temperature versus depth data for artesian wells in the San Simon area. 70 Geology Subsurface geology controls the distribution of the confined aquifers. These confined aquifers are contained in permeable sediment, which is over- lain by an impermeable cap rock. Drillers' logs of the San Simon area were interpreted to delineate subsurface stratigraphy and locate the thickness and lateral extent of the confining cap rock. In the San Simon area, artesian wells tap water contained in sand and gravels, which are below a blue clay. This blue clay is probably correlative with the green clay facies of Harbour (1966) at Safford. Fortunately, the blue clay is easily distinguished from other basin-filling sediments; as a result, drillers' logs are highly useful in mapping its subsurface extent and thickness. Figure 26 is a structure contour map at the base of the blue clay. The blue clay is deposited in a wedge-shaped depositional basin bounded by steep structure contours oriented NNW and WNW. A structure contour map of the top of the blue clay (Figure Zn exhibits the same geometry as that seen at the base of the blue clay except that the con tours delineating the margins of the deposition basin are not as steep. The closure over the lowest elevation at the top of the blue clay is displaced to the south from the site of the lowest elevation at the base of the blue clay; the closure is adjacent to steep contours oriented WNW. The well showing the lowest elevation for the top of the blue clay records a significant evaporite occurrence. At this location, evaporites overlie the blue clay. The evapo rite sequence may represent deposition during the dessication of a lake in closed basin conditions. Structural and tectonic inferences are tentatively drawn from the struc tural contour maps. The steep structure contours of the blue clay may cor relate with faults that control the location of the depositional basin. In addition, faulting contemporaneous with dessication of a late Tertiary lake 71 .- ... - ~ ~- 0 , ." 17 to ~, "-' . ... " -" " " '. .. 2' j ELEVATION AT THE BASE OF THE "BLUE CLAY" Elevation above sea level (Feet). o I Mile L.'__---'I Figure 26. Structure contour map of the base of the blue clay unit in San Simon area.- 72 " '"",.- ~--- ,....~, " ~. 7 '1.v-~. 10 ~;, 11 .11 .s' "'~ ••••• :;;~ I -f"'~ , 0 .8 1- 17 lB \~u " y .y .... L " ... ----- ~ r', I ELEVATION AT THE BASE OF THE "BLUE CLAY" Elevation above sea level (Feet~ 1"~111l 0 IMile '26 ry '" '0 I 3600 + \ 3614- N ., \ .'~ I ,. ,~, " ·3590 " .. \~~_. ... Figure 27. Structure contour map of the top of the blue clay unit in the San Simon area. 73 may displace the last remnants of this lake to the location adjacent to the ~~W-oriented structure contours, thereby localizing the evaporite sediments. As an analogy, sag ponds or small lakes sometimes occur on the downthrown block adjacent to large Holocene faults. Geohydrology The blue clay apparently influences the geohydrology of the area. Fig ure 28 is a piezometric surface map of the confined aquifer. The shape of the piezometric surface coincides with the shape of the structure contour map at the base of the blue clay. Steep contours on the piezometric surface map indicate a damming effect on subsurface water flow to create rapidly changing hydraulic pressure. Low-permeability sediments or an impermeable fault zone can cause ground water falls or steep hydraulic gradients. Be cause the blue clay thickens rapidly at these ground water falls, it is be lieved that ground water flow is forced downward beneath the low-permeability blue clay. Estimated average temperature gradients of individual wells, using sur face discharge temperature, mean annual temperature and well depth, are plotted o in Figure 29. Wells with temperature gradients less than 40 C/km coincide with ground water falls. Downward-flowing water would transport heat, causing lower temperature gradients. Chemistry Most thermal waters encountered in artesian wells are sodium bicarbonate composition. In the northern portion of the study area, sodium chloride sulfate water with TDS up to 5,400 mg/l is encountered. Fluoride and boron contents of these later waters are exceptionally high, with fluroide concen trations over 25 mg/l. 74 o 1 Mile '2, WATER LEVEL OF WELLS IN THE SAN SIMON AREA, 1915 >- 3698 Water level above sea level, elevation in feet -;'6-~-'~~ • ~, Figure 28. Map of water level of artesian wells in the San Simon area in 1915. 75 ',~ ---...-..--_.- .- Figure 29. Estimated temperature gradients of artesian wells in the San Simon area in 1915. 76 Conclusion Geothermal potential at depths greater than 1 km in the San Simon area may be good. In 1938 a deep oil and gas test, the Bunk Benevolent 1 Fee, was completed to 2,032 m depth. In a 1940 memorandum, E.D. Wilson of the Arizona Bureau of Mines gave an account of a visit to this well site where he was told that 134°C water was encountered in the lower 100 m of the hole (see Appendix 3). If this temperature accurately describes bottom conditions, o the estimated temperature gradient is 57 C/km. This temperature gradient is above the 46.6°C/km average, estimated using shallow (300 m) well data. Because the oil test gradient is above normal, lies in a possible fault zone (in a zone of steep WNW-trending structural contours of the blue clay) and reportedly encountered water at 2 km depths, the San Simon area may have good potential for 1 to 2.5 km depth geothermal resources between 100 and 140oC. 77 Bowie Area Introduction At least 20 irrigation wells in the area surrounding Bowie pump 30 to 37°C water from depths of 183 to 610 m (Table 1, Figure 1). Chemical quality of the thermal water is good; TDS of these waters ranges mostly between 250 and 500 mg/l (Table 2). Fluoride concentrations are generally less than 3.0 mg/l; although a few wells produce water with fluoride over 7.0 mg/l. These thermal waters are useful for irrigation and a few are suitable for drinking because their fluoride contents are less than 1.4 mg/l. Geochemistry A wide variation of dissolved constituents occurs in the thermal waters at Bowie. Most of these waters are either sodium bicarbonate or sodium chloride- sulfate chemistry, and they have no readily distinguishable correlation among chemical type and measured temperature. This may indicate that the variability in compositions is due to contact of these waters with different kinds of rock in shallow «600 m) aquifers. Chemical geothermometer calculations are also highly variable; thermal waters which have very low calcium and magnesium concentrations have the highest Na-K-Ca geothermometer temperatures (Table 3). Waters with relatively very low magnesium concentrations are frequently associated with the higher tem- perature zones of known geothermal systems (Ellis and Mahon, 1977). The sodium bicarbonate chemistry of these waters suggests that the reservoir is contained in basement rock composed of either fractured volcanic or felsic crystalline rocks. A deep reservoir temperature of l24°C is inferred by the Na-K-Ca geothermometer. In other waters, all of which have relatively high calcium concentration and which are trending toward sodium chloride-sulfate chemistry, the calculated Na-K-Ca temperatures are all below 95 oC. The Na-K-Ca 78 geothermometry for waters containing higher calcium, chloride, and sulfate concentrations are believed unreliable due to possible mixing, dissolution of gypsum, and cation exchange reactions with clay in the basin-fill sediments. Na-K-Ca geothermometry assumes that temperature-dependent equilibrium with silicate minerals in the reservoir has occurred and that no additional reac tions have changed the ratios of sodium, potassium, and calcium after the thermal water leaves the deep reservoir (Fournier and others, 1974). Figure 30 is a map of the Bowie area showing the distribution of the Na-K-Ca geo thermometer temperatures. Wells with the highest Na-K-Ca temperatures may overlie fractured basement, which is leaking thermal water into shallow «600 m) aquifers. Additional studies are required to confirm the high Na-K Ca geothermometer temperatures obtained using the low magnesium, sodium bi carbonate waters because the sodium, potassium and calcium ratios may also reflect shallow nontemperature-dependent dissolution of silicate minerals in a high dissolved carbon dioxide environment (Paces, 1975). Structure and Stratigraphy Geophysical studies by Eaton (1972) and drillers' logs provide a basis to describe the subsurface geology in the Bowie area. Eaton (1972) published a subsurface model of structure based upon an accompanying gravity profile. Figure 31 shows Eaton's structural model and gravity profile. His profile locations are shown in Figure 32, Gravity interpretation by Eaton (1972) shows a graben, which is about five miles wide and filled with up to 760 m of clastic sediment. Tertiary volcanic rock, 300 to 600 m thickness, are modeled to underlie the basin-fill sediments. Drillers' logs published in 'fuite (1963) and White and Smith (1965) show the stratigraphy of the upper portion of the basin-filling sediments in the Bowie graben (see drillers' logs in the appendix), A "blue clay" strata, 79 MAP SHOWING DISTRIBUTION OF Na-K-Ca GEOTHERMOMETER TEMPERATURES - BOWIE AREA ') to 10 .' \ ',. \ " ;!i ;- 21 \ "'-: ....<... ~ ~." ~:'·:··>l. "n '-. : "'46 'f " : '16 31 '2 \ • •S ,. ... 76 No- K-Co N Geothermometer ·C ZMllu __-IOO·C No- K- Co Isotherm -[- Figure 30. Map showing distribution of Na-K-Ca geothermometer temperatures in the Bowie area. 80 GRAVITY MODEL OF THE BOWIE AREA Modified from Eaton, 1972. Location of Gravity Profile Shown in Figure 32 LITHOLOGY A' DENSITY o A 3 c:=J f=2.259/cm OBSERVED LATE TERIARY- QUATE RNARY GRAVITY~ BASIN FILL SEDI MENT cm3 MODEL [<:1 f =2.50 9/ -15LI-__- ~GRAVITY MIOCENE TO LATE TERTIARY VOLCANIC ROCK l222d f= 2.40 9/cm3 EARLY TERTIARY OR MESOZOIC West East ~ j>=2.70 9/cm3 ++++++++++\\ + + + + + + + + + +.v PRE-TERTIARY BASEMENT ~ 500 + + + + + + + + + +\ ~ ++++++++++\ Q) ++++++++++ FAULT ARROW ON ~ 1000 +++++++++++ +++++++++++++ DOWN DROPPED .s= ~~~++++++++++++++ a. +++++++++++++ I SIDE ~ +++ ++++++++++++++ 1500- +++++++++++++++++++ ++ +++++++++++++++++++ ++++++++++++++++++++++ 2000 + + VERTICAL EXAGGERATION 5.28 + + + o 5 Mil•• I o 5 Kilom.t... ! , Figure 31. A gravity subsurface model of the Bowie area. 81 BOUGUER GRAVITY MAP OF BOWIE' AREA WITH LOCATIONS OF GROUND WATER FALLS AND PROFILE USED TO MODEL SUBSURFACE STRUCTURE 'I GA I Center of Bouguer Gravity :~----7~\-~;iR ,/ ... ~«-- .I Anomaly East of BOWIe _t\/\>~ . / ):fte1lC1-~ • --160- r~~I Bouguer Gravity contour l~,~':J Contour interval is 5 mi lIigals C' . , 1\-,,,. , fi~~?\:- -~-J -:?'~4 ./1 1975, Ground-water fall (See .; ';' '.ii.,~'b \" { - ' j 1,\ Figure 34, Ground-water Table ,I "'/,\ \ Map of the.Bowie area,) "r ' - I, ",,'\1 A AI (X) N ,~ ~.J ~.l'~ .. II _ .. " Gravity profile used to model .~. , subsurface geology, (See Figure 31 t--"-'--t-' I~I W~-ldl'lj Gravity Model of Bowie Area.) 1 \ I: \ I t~v> DATA SOURCES: (I) 'GRAVITY-Wynn and Dansereau, 1979. (2) PROFI LE - Eatont 1972. (3}GROUND-WATER TABLE -Information for 1975 j Wilson and White, 1976. BASE: US, Geological Survey 1:25Q!000, Silver City, 1970, N SCALE: 1:250,000 0 6 Miles III «, II -r- Figure 32. Bouguer gravity map of Bowie area compared to' locations of ground-water falls. TRANSVERSE TOPOGRAPHIC PROALES ACROSS THE SAN SIMON VALLEY AFTER EATON, 1972 330'r----16------rT---'~ 8 _ Duncan: a~ :~ 'I~ e;, ~,~ 4l:1 .J ARROWS POINT TO CONVEX ~5 $ C TOPOGRAPHY A ~I r ll::, Lordsburg'l • "1:, Bowie I r ~4 sri •Willcox ~ 3 st'IIIII 3~1...------~""-----..... o 25 Mil•• I I I o 25Kllom.'." 2 I ! I I ! I METERS 122[ VERTICAL EXAGGERATION 61~ X26 o 2 4MILES ALL PROFILES EXCEPT 4 AND 5 SHOW CONCAVITY. PROFILES 4 AND 5 CROSS GRAVITY ANMOMALY (GA) SHOWN IN FIGURE 32 Figure 33. Topographic profiles across the San Simon Valley. 83 1975, GROUND-WATER TABLE MAP OF THE BOWIE, ARIZONA AREA After Wilson and White (1976). ...... ,.. I."ll-" '.-;. / " / "J I I .... .~ I " I \ 1 " \ "'" \ 31 ~'" 32 lI... t~~~l" .. \ , ,. . 0. --;-. rio / N '00- Groundwater table elevation 2Mil.. ___ "!>~ contaur (in feet abave sea level! -)- 6===='===='1 Figure 34. Map of water table in the Bowie area in 1975. 84 probably correlative with the "blue clay" at San Simon and possibly the green clay facies of Harbour (1967) at Safford, overlies water-bearing sand and gravel. The blue clay is over 120 m thick in a well two miles northeast of Bowie, but it pinches out or thins considerably near Interstate 10. South of Interstate 10 the blue clay is absent or very thin «15 m). The blue clay is an aquaclude; and ground water below the clay had artesian pressure before extensive ground water development in the area lowered the water table (piezometric surface) in the deeper aquifers (White, 1963). By 1975, ground water pumpage had created a ground water depression be neath this area (Wilson and White,1975). Zones of steep water table contours on the west, south and east sides of the depression may indicate zones of lower permeability caused by faults (Figure 34). These ground water falls roughly correspond with the margins of the graben as deduced from Bouguer gravity data (Figure 33). Active Tectonism Recent tectonic deformation is inferred in the Bowie area. While no Recent or Quaternary fault scarps are identified in the Bowie area, studies by Eaton (1972) and Holzer (1980) point towards tectonic uplift, during Recent time, of the horst bounding the east side of the Bowie graben. Eaton (1972) presents first-order leveling data, which shows uplift, between 1902 and 1952, of this horst relative to bedrock benchmarks on either side of the San Simon basin. In addition, Eaton (1972) discusses topographic profiling in the Safford-San Simon basin (Figure 33). All profiles except those tra versing the Bowie area are concave, while the Bowie topographic profiles are convex. The anomalous convex Bowie profiles could be interpreted as evidence of tectonic uplift (Eaton, 1972). Holzer (1980) has mapped earth fissures and cracks, resulting from sub- 85 sidence that was created by ground water removal. Additional leveling data reported by Holzer (1980) show up to 1.25 m of subsidence since 1972 over the graben, but no net uplift over the horst. However, Holzer (1980) pointed out that aerial photographs taken in 1935 over the Bowie area show many polygonal earth fissures over the horst. No significant ground water withdrawal occurred before 1935; therefore, these fissures may not be subsidence related. As to whether or not the 1935 earth fissures are definitely related to uplift of the horst, it is speculative, because earth fissuring in many areas of south- eastern Arizona is reported by DuBois and Smith (1981) during the 1887 Sonoran earthquake. Therefore, the fissures seen in 1935 photographs may have originated during the Sonoran earthquake and may not indicate local tectonism. Conclusion A spatial coincidence of wells, producing sodium bicarbonate water with low magnesium, high Na-K-Ca geothermometers, and an apparent structural inter- section, which is inferred from ground water falls and gravity data, support the hypothesis that a deep (>2 km) moderate-temperature geothermal reservoir o (~124 C) occurs south of Bowie. Well D-13-28-l5DCC, which has the highest Na- K-Ca temperature (124°C), is the most anomalous well from a temperature and o depth standpoint. This well, 145 m deep, has a discharge temperature of 35 C and an estimated average temperature gradient of l24°C/km. All other wells in o the area have estimated temperature gradients between 30 and 80 C/km and a mean temperature gradient of 49 0 C/km. Further studies are advised before drilling a deep test into this possible deep reservoir. Heat flow studies and geochemical modeling are needed to site a deep hole. A shallow «600 m) geothermal resource does exist at B~wie and it has a reservoir temperature ranging between 35 and 45 0 C. The geothermal water has 86 excellent chemical quality suitable for most agricultural uses. Aquaculture, greenhouses, and space heating are potential uses of this water. 87 Whitlock Mountains Area In 1927 and 1928 the Pinal Oil Company Whitlock Oil #1 State was unsuc- cessfully drilled for oil in D-10-28-36AD. However, the hole encountered a o strong artesian flow of thermal water (4l C) from conglomerate below 440.4 m to total depth at 586.7m. Today artesian flow of thermal water from this well continues. An additional oil and gas test, the Bear Springs Oil #1 Allen, formerly discharged "lukewarm" water (Knechtel, 1938). This well, drilled to 473.9m, has since been destroyed. The Badger Den well, D-10 o 29-20AC, discharged 34.l C water in the late 1970s (Swanberg and others, 1977). Presently, this well is inoperative due to pump removal. These thermal wells at the southern terminous of the Whitlock Mountains o indicate a significant low-temperature «100 e) geothermal resource suitable for direct-heat use in agricultural applications. Total dissolved solids (TDS) between 1,100 and 700 milligrams per liter (mg/l) are reported for water dis- charging from thermal wells in the area (Table 2). These thermal waters are sodium chloride-sulfate composition and they contain fluoride concentrations exceeding five mg/1 (see Table 2) • Siltstone and clay to 440m provide a confining cap rock over con- glomerate aquifers in the vicinity of the Whitlock #1 well. Fractured Terti- ary volcanic rock may host the thermal aquifer for the Badger Den well. Chemical geothermometry, using the Na-K-Ca geothermometer, predicts 104 to 132oC deep subsurface temperature. Caution is advised, however, in using these results because further geochemical and geophysical studies are required o to confirm a deep intermediate-temperature (100-150 C) resource. Additional wells 457 to 610m depth are likely to encounter 40 to 50 0 C water and may produce artesian flow exceeding 200 gallons per minute. 88 Table 1 Wells With Measured Temperatures >30oC In The Safford-San Simon Basin Depth Temperature Location Temperature (oC) (Meters) Gradient (oCjkm) Source D-5-24-16 CB 4803 183 166 1,4 D-5-24-17 AD 48 03 183 166 4, 12 D-6-24-4 CBB 47.8 18 1655 4, 12 D-6-24-13 AB 58.9 1148 36 4, 5, 6 D-6-25-36 CBB 46.0 660 42 4, 9, 10, 12 D-7-24-17 BD 30 0 6 11 1145 4 D-7-25-22 DDD 43.3 416 61 7 D-7-27-1 BBA 37.8 76 260 9 D-7-27-2 AAA 37.2 122 157 9 D-7-27-2 ACD 38 0 0 122 164 8, 10 0'1 D-7-27-2 ADD 41.0 122 188 9, 12 co D-7-27-2 CC 35.6 91 193 5, 9 D-7-27-11 BBB 43.5 122 209 10 D-7-27-11 BBB 49.0 133 233 14 D-8-25-1 DDD 36.0 213 85 5, 6 D-8-25-12 AA 30.6 305 41 6 D-8-25-12 AA 36 07 320 58 4, 5 D-8-25-12 AAA 39.0 366 57 9, 10, 14 D-8-25-12 ABA 30.0 180 67 7 D-8-25-12 AC 34.4 320 51 4 D-8-25-12 AD 32.2 244 58 6 D-8-25-12 AD 32.2 274 52 6 D-8-25-12 AD 34.4 122 134 5,9 Table 1 cont. Wells With Measured Temperatures >30oC In The Safford-San Simon Basin Depth Temperature Location Temperature (oC) (Meters) Gradient (oC/km) Source D-8-26-7 DA 41.5 488 48 9, 10 D-8-26-7 DDA 39.0 421 50 9, 14 D-8-26-7 DDB 35 0 0 381 45 9, 14 D-8-26-7 DDB 38.0 387 52 9, 14 D-8-26-8 BDC 39 0 4 195 110 10, 16 D-8-26-18 AC 33.9 274 58 6 D-8-26-18 DDA 42.0 463 52 9, 10 D-8-26-20 AB 30.6 213 59 6 D-8-26-20 DBC 45 0 0 390 69 10, 6 0 D-8-26-28 ABC 31 244 53 7 0"\ D-8-26-32 CB 32 0 2 110 129 6 D-8-26-32 DB 32 0 2 122 116 6 D-8-26-32 DC 32.8 122 121 6 D-8-26-33 AC 32.8 226 65 6 D-8-26-33 CA 32.8 122 121 6 D-8-26-33 CA 33.3 152 100 6 D-8-26-33 CCC 31.0 132 99 9, 14 D-8-26-6 CCB 31.0 227 57 9 D-9-30-11 DD 72.2 98 553 4 D-10-28-25 DD 36 0 0 474 38 4, 6, 12 D-10-28-36 AAC 41.1 587 39 1, 4, 5, 6, 10, 12, 13 D-10-29-20 AC 34.1 160 101 10, 15 ...... D-11-29-36 CBB 32.2 207 69 2, 10, 13 Table 1 cont. Wells With Measured Temperatures >30oC In The Safford-San Simon Basin Depth Temperature Location Temperature (oC) (Meters) Gradient (oC/km) Source D-8-25-12 DA 31.4 161 83 6, 9 D-8-25-12 DBD 30 213 56 7 D-8-26-7 ABA 42.0 467 51 7 D-8-26-7 AB 30.0 253 47 6 D-8-26-7 ACC 30.0 274 44 7 D-8-26-7 AC 35.0 329 52 6 D-8-26-7 AC 30.0 213 56 6 D-8-26-7 ADD 34 305 52 7 D-8-26-7 AD 30 0 6 274 46 6 D-8-26-7 ADC 32.0 243 58 9, 10, 14 .-l D-8-26-7 BAA 41.5 463 51 9, 10 '" D-8-26-7 BA 35.6 344 51 6 D-8-26-7 BBB 34 262 61 6, 10 D-8-26-7 BB 35.8 320 56 6 D-8-26-7 BDB 32.0 335 42 7 D-8-26-7 BDB 38.0 476 55 7 D-8-26-7 BDB 34.4 464 35 9 D-8-26-7 BDB 32.0 415 34 7 D-8-26-7 BD 33.3 396 39 6 D-8-26-7 BD 35 366 46 6 D-8-26-7 BD 33.9 299 53 6 D-8-26-7 CA 37 0 0 244 78 6, 10 D-8-26-7 CD 33.9 290 55 6 Table 1 cont. Wells With Measured Temperatures >30o C In The Safford-San Simon Basin Depth Temperature Location Temperature ( °C) (Meters) Gradient (oC/km) Source D-12-28-10 CCC 35.5 305 58 10, 14, 15 D-12-28-22 CDC 31. 5 200 68 2, 4, 12 D-12-28-23 CCC 32.2 305 47 9 D-13-28-1 BB 30.0 218 55 12 D-13-28-3 C 37.2 244 79 2, 4 D-13-28-4 DDB 37.2 253 76 12, 13 D-13-28-9 BCC 31.0 213 61 12, 13 D-13-28-10 BC 36.0 305 59 9, 10 D-13-28-15 CCC 31.7 139 99 9 N Cl'\ D-13-29-6 CCC 31.1 255 51 12 D-13-29-6 CC 31.1 214 61 4 D-13-29-24 CD 40.6 293 77 5 D-13-29-24 DCC 40.6 293 77 2, 8, 12, 13 D-'13-29-27 ACC 33.3 311 49 3 D-13-29-36 AD 43.3 305 83 11 D-13-29-36 ACC 35.6 305 58 11 D-13-29-36 ADC 36.7 229 82 11 D-13-30-3 B 42.8 262 95 8 D-13-30-3 BeC 33.5 262 59 12 D-13-30-3 BDe 33.3 262 58 13 D-13-30-9 ACD 34.0 274 58 5, 8, 9, 12 D-13-30-11 BCC 32.2 290 49 5, 8, 12, 13 D-13-30-13 A 31.1 232 56 8 Table 1 cant. Wells With Measured Temperatures >30o C In The Safford-San Simon Basin Depth Temperature Location Temperature (oC) (Meters) Gradient (oC/km) Source D-13-30-14 DDD 32.2 284 50 5, 8, 9, 12, 13 D-13-30-15 DAA 35.0 397 43 5, 8, 12, 13 D-13-30-23 ACC 30.6 274 46 12, 13 D-13-30-23 B 33.3 274 56 4, 8 D-13-30-25 ACD 30.5 268 47 5, 12 D-13-30-27 AD 134.4 1952 60 4 D-13-30-30 B 40.6 284 80 8 D-13-30-30 BCB 40 293 75 5, 13 D-14-30-36 AA 75.6 2312 25 4 ('1") D-13-30-36 DDD 41. 7 610 39 3 m D-14-30-12 ADB 30.6 279 45 9, 12, 13 D-14-31-16 DCC 31.6 610 22 2, 9, 12, 13 D-14-31-21 BCC 32.2 217 65 9, 12, 13 D-16-31-10 AA 54.4 1657 22 1, 4 Sources (1) Conley, J.N., and Stacey, D.A., 1977 (10) Swanbere, C.A., and Others, 1977 (2) DeCook, K.J., 1952 (11) Harold Wardlaw, Pres. Carom. ( 3) Dut t, G. R. , and McCreary, T.W., 1970 (12) WATSTORE (4) Giardina, S, 1978 (13) White, N.D., 1965 (5) Hem, J. D. , 1950 (14) This Report (6) Knechtel, M.M., 1938 (15) Wilson, R.P., and White, N.D., 1976 (7) City of Safford (16) Witcher, 1979 (8) Schwennesen, 1918 (9) State Land Department Table 2 Chemical analysis of ground waters in the Safford~SanSimonbasin area Results in milligrams per liter except as noted (see data sources) Temperature in degrees celsius Remarks: S - spring W- well Data Sources: 1. Arizona Bureau of Geology and Mineral Technology 2. Dutt and McCreary, 1970 3. Hem, 1950 4. Muller and others, 1973 5. Swanberg and others, 1977 6. Files, U.S. Geological Survey Tucson, Arizona 7. White and Smith, 1965 Location Key: D-3-3l-3 ADCC Quadrant Township Range Section Quarter 94 Table 2A. Analyses of Gila Valley-Indian Hot Springs ground waters Number 8amp1e Location Temperature TD8 pH Na K Ca Mg c1 HC0 +C0 810 Li B F Remarks Data Source 8°4 3 3 2 Na+K 1 57 D-6-25-36CBBB 46 4431 6.8 1390 13.1 64 7.6 4011 672 64 55 2.3 0.6 6.7 W 1 2 53W86 D-5-24-17ADDCA 46 2967 7.5 670 13 39 7.2 1430 365 69 45 1.41 1.64 2.8 8 1 3 54W80 D-5-24-17ADDDB 45 2929 7.5 540 14 38 7.1 1414 348 98 48 1.42 0.94 5.2 8 1 4 55W80 D-5-24-17ADDBB 47 7.5 610 14 38 8.0 1257 325 120 49 1.25 1.64 4.0 8 1 5 1817 D-5-24-17AD 47.8 2570 - 879 78 9.6 1195 348 105 - - 2.0 3.9 8 3 6 1818 D-5-24-17AD 40 2970 - 1027 83 11 1400 395 106 -- 0.8 4.8 8 3 7 1822 D-5-24-17AD 47.8 2970 - 1023 81 14 1400 402 101 - - - 3.4 8 3 8 1823 D-5-24-17AD 47.8 2960 - 1026 80 12 1400 393 100 - - 0.8 4.6 8 3 9 2600 D-6-24-13AB 58.9 3530 - 1220 74 8.7 1660 416 101 - - 7.0 6.0 W 3 10 2683 D-7-24-17BD 30.0 2740 - 739 226 33 1250 426 116 - - 8.0 1.4 W 3 AZ10 2672 837 323 44 1.30 0.58 3.4 8 5 If) 11 D-5-24-17A 47 7.9 13.6 80 9.0 1196 107 m 12 AZ11 D-5-24-17A 46.5 3004 7.9 10Z3 12.9 93 10.3 1382 361 101 44 - 0.70 3.8 8 5 13 AZ14 D-6-25-36C 43.5 8292 7.9 3027 10.9 135 7.9 4517 787 81 66 2.77 1.65 7.2 W 5 14 AZ21 D-5-24-17AD 33 3048 7.5 921 12.9 81 8.0 1412 338 109 57 - 0.84 3.9 8 5 15 AZ155 D-7-25-7CCC 29.5 9288 8.1 3072 14.5 133 28 3956 1455 46 27.5 4.05 2.33 6.27 W 5 16 AZ156 D-7-24-14DD 25.5 1804 8.3 709 2.7 9.2 0.7 688 452 107 27.0 - 1.62 7.8 W 5 . Ii, Table 2B. Analyses of Buena Vista area ground waters Location Temperature TDS B F Remarks Data Source Number Sample pH Na K Ca Mg C1 S04 HC0 +C03 Si02 Li Na+K 3 3548 D-7-27-10AAD 792 7.7 163 69 15 218 70 244 1.0 W 4 1 58 D-7-27-11BBB 49 1094 7.5 333 3.9 1 0.1 212 272 205 62 0.4 <.1 10.2 W 1 2 59 D-7-27-2ACB 38 1117 7.3 360 3.5 1 0.4 249 265 195 61 0.4 <.1 8.6 W 1 3 74 D-6-27-35DDDD 27 894 7.4 284 2.9 1 0.4 232 120 202 52 0.3 0.3 6.9 W 1 4 17W80 D-7-27-2AADC 36 826 8.6 52 4.5 19.6 2.6 189 24 122 28 0.2 <.01 4.8 W 1 5 18W80 D-7-27-11BBBB 46 1011 7.9 60 1.0 4.5 0.1 201 190 124 31 0.1 <.01 4.1 W 1 6 19W80 D-7-27-2ADBB 40 961 7.6 61 0.8 12.4 0.4 210 111 134 27 0.1 <.01 7.0 W 1 7 30W80 D-7-27-2ADDCB 39 1055 8.3 321 3.8 0.6 0.2 195 180 186 63 0.4 13 W 1 8 8307 D-7-27-7 46.1 8.6 368 4.7 7 2 256 270 239 65 0.2 0.46 9.0 W 2 9 927 D-7-27-2CC 35.6 1029 369 9.5 6.6 230 275 259 11 W 3 10 AZ15 D-7-27-1lBBB 43.5 1076 8.5 331 4.3 7.4 1.3 203 296 246 67 0.36 0.43 10.6 W 5 5 \0 11 AZ16 D-7-27-2ACA 37.5 1012 8.4 358 3.9' 6.2 1.0 168 227 259 67 0.46 10.2 W Cl'I D-7-27-2ADD lil.O 360 4.3 4.3 0.9 240 250 255 65 0.49 14.0 W 7 3428 D-7-27-1lBBB 1077 7.6 365 4.4 0.97 220 150 223 9.5 W 4 3434 D-6-27-36CCC 956 7.6 320 5.6 0.49 246 105 254 2.95 W 4 3438 D-6-27-36CCC 888 7.5 290 4.4 0.97 244 110 210 4.65 W 4 3439 D-7-27-04DAA 1064 7.6 217 101 22.9 246 120 337 1.75 W 4 3441 D-7-27-04DAA 1045 7.6 209 103 22.4 248 110 303 1.55 W 4 3444 D-6-27-34DCC 1544 7.4 327 118 37.2 410 200 415 2.45 W 4 3445 D-7-27-8ADD 1281 7.6 205 ·109 28.5 344 190 366 2.10 W 4 ) Table 2B. Analyses of Buena Vista area ground waters. continued Number Sample Location Temperature TDS pH Na K Ca Mg C1 HC0 +C0 Si0 Li B F Remarks Data Source S04 3 3 2 Na+K 3449 D-7-27-8DBB -- 1371 7.6 280 --- 124 29.2 370 200 366 ------2.10 W 4 3453 D-7-27-2ACA -- 1096 7.6 256 -- 80 16.4 342 130 264 -- -- - 2.05 W 4 3458 D-6-28-31DAC -- 817 7.6 167 --- 70 18.0 252 70 237 ------1.32 W 4 3464 D-7-27-16CBA -- 1315 7.7 215 -- 92 23.0 350 240 427 ------2.85 W 4 3465 D-7-27-09ABB -- 1248 7.5 235 -- 114 27.4 332 160 356 ------1.55 W 4 3471 D-7-27-0lBBA -- 786 8.8 264 -- 4.0 0.24·216 75 214.4 --- - - 2.9 W 4 3484 D-7-27-lOABC -- 1106 8.3 365 -- 16.8 3.7 256 230 222.2 ------7.5 W 4 3514 D-6-28-3lADA -- 985 8.6 193 -- 100 21 372 80 210 ------1.3 W 4 3519 D-7-27-1BAC -- 875 7.8 285 --- 1.35 1.5 195 120 256 -- - -- 4.85 W 4 3543 D-7-27-lADD -- 1144 8.4 359 --- 6.2 1.34 250 250 265.6 ------7.3 W 4 3488 D-6-27-35DDD 814 8.7 237 3.6 0.49 228 120 212 7.0 W 4 ------l' 0\ 3489 D-7-27-1BBB -- 830 8.4 283 -- 5.2 0.49 200 90 16.6 --- - - 4.3 W 4 3501 D-7-27-20AAA -- 1383 7.7 315 -- 68.8 16.5 320 250 390 ------3,4 W 4 3502 D-7-27-17DBA -- 1169 9.0 192 -- 129 29.0 236 170 386 ------1.8 W 4 3503 D-7-27-17DDA -- 1265 7.5 283 -- 120 25.3 246 170 395 -- -- - 2.0 W 4 3506 D-7-27-02AAA -- 830 8.5 241 --- 6.2 0.73 194 120 247.4 -- - - 7.0 W 4 3511 D-7-27-01BAB -- 623 8.5 260 --- 4.0 0.36 232 80 243.6 ------2.85 W 4 Table 2C Analyses of Cactus Flat-Artesia area ground waters Number Sample Location Temperature TDS pH Na K Ca Mg C1 HC0 +C0 S10 Li B F Remarks Data Source S04 2 Na+K 3 3 1 25 D-8-25-12AAA 39 2447 8.6 881 7.7 50 0.9 941 535 32 17.6 - - - W 1 2 26 D-8-26-7DDA 39 1345 8.8 470 3.5 15 0.2 503 335 33 18.5 W 1 3 27 D-8-26-8BDCC 39 2866 8.5 1152 10.6 31 4.3 1066 607 90 14.1 W 1 4 28 D-8-26-20DBCC 45 1358 8.4 579 5.8 17 0.6 510 290 79 18.4 W 1 5 29 D-8-26-6CBB 31 1767 7.5 644 2.7 1 0.5 538 330 223 17 0.8 2.5 8.6 W 1 6 33 D-8-26-7BBB 34 1402 7.7 444 3.0 9 0.4 457 313 42 18 1.3 0.7 10.2 W 1 7 34 D-8-25-12AAA 39 2803 7.1 810 5...:1 26 0.8 965 542 31 20 2.1 0.3 7.8 W 1 8 - 52 D-8-25-1DDD 36 1774 7.4 605 .3.1 19 0.6 655 392 42 20 1.7 0.6 11.0 W 1 9 53 D-8-26-7ADC 32 1315 7.7 474 2.6 2 0.5 483 309 129 15 1.0 0.6 8.3 W 1 10 54 D-8-26-7DDA 39 1367 7.5 449 2.4 15 0.2 505 300 38 22 1.3 0.1 12.5 W 1 11 55 D-8-26-7DDB 35 1325 7.6 448 2.2 13 0.2 424 325 40 22 1.5 0.1 12.0 W 1 12 56 D-8-26-7DDB 38 1634 7.5 539 2.8 22 0.2 580 377 38 23 1.6 0.3 11.5 W 1 13 75 D-8-26-33CCCC 31 685 7.9 171 4.3 75 2.8 82 345 110 33 0.3 4.8 5.2 W 1 00 0\ 14 76 D-8-26-32DCC 28 523 8.3 161 1.6 3.4 0.6 111 265 113 28 0.3 5.1 9.8 W 1 15 94 D-8-26-19DCCB 27 231 7.3 21 2.1 8 3.9 16 5 132 50 0.1 0.4 1.1 W 1 16 95 D-8-26-19CDDA 27 243 7.5 23 2.2 7 4.1 19 6 116 47 0.1 0.2 1.2 W 1 17 96 D-8-26-19CDDB 27 429 8.0 48 3.1 14 2.7 108 58 104 36 0.3 0.5 1.0 W 1 18 97 D-8-26-19CDDBC 29 679 8.0 60 2.8 10 2.0 201 95 96 34 0.5 <0.1 1.8 W 1 19 98 D-8-26-33CCD 34 690 8.0 61 3.6 13 1.8 156 120 118 26 0.3 0.7 0.5 W 1 20 1081 D-8-26-32DC 33.3 456- 9.5 3.9 101 88 164 - -- 10 W 3 21 AZ12 D-8-26-7DD 42 1152 8.5 524 3.9 21 0.4 204 282 83 24 - 0.90 13.6 W 5 22 AZ13 D-8-26-7AB 45 2256 8.1 1054 6.6 69 2.6 447 605 48 20 - 1.29 9.0 W 5 23 AZ17 D-8-26-20CD 44 1248 8.4 498 4.3 16 0.7 197 267 99 26 1.38 0.55 14.2 W 5 24 AZ22 D-8-26-7DA 41.5 1992 8.5 678 3.9 22 0.5 818 369 43 28 - 1.04 9.6 W 5 Table 2C. Analyses of Cactus Flat-Artesia area ground waters, continued Number Sample Location Temperature TDS pH Na K Ca Mg C1 HC0 +C0 Si0 Li B F Remarks Data Source S04 3 2 Na+K 3 25 AZ23 D--8-25-12AAA 39 2660 8.5 783 5.5 65 1.1 1024 497 34 28 2.40 1.18 8.4 W 5 26 AZ24 D--8-26-7AC 37 1160 8.8 384 2.3 18 0.2 418 294 54 31.7 - 0.8 11.7 W 5 27 AZ25 D-8-26-7BA 34.5 1116 9.0 379 2.3 7.2 0.2 399 247 82 28 - 0.94 13.95 W 5 28 AZ26 D--8-26-7BB 33.5 900 8.9 306 1.6 9.2 0.1 294 195 60 29 - 0.60 14.55 W 5 29 AZ28 D-9-26-5BA 33 504 8.5 161.9 1.2 4.6 0.1 109 106 146 28 - 0.28 10.35 W 5 30 AZ29 D-9-26-5BA 33 740 8.2 249 2.3 17.2 1.0 151 172 218 29 - 0.30 14.55 W 5 31 AZ59 D-8-26-8CA 39.4 3000 7.9 1025 6.2 42.1 5.7 1125 585 117 22 2.32 1.78 9.45 W 5 32 AZ60 D--8-26-9BC 29.4 9048 7.6 3283 14.1 67.9 20.7 4097 1688 165 30 5.16 8.40 1.17 W 5 33 AZ61 D--8-26-9BC 38.9 1464 7.9 442.8 6.2 37.7 11.4 365 410 172 20 0.93 2.06 5.40, W 5 34 AZ119 D--8-26-20DC 39.4 816 8.8 303.5 1.2 7.2 0.1 260 203 95 28 - 0.84 14.54 W 5 '" /' r) :"") .... }! ..-... / j .' Table 2D. Analyses of SaIl Simon area ground waters Number Sample Location Temperature TDS pH Ca C1 HC0 +C0 Sia Li F Remarks Data Source Na K Mg S04 2 B Na+K 3 3 1 47W80 D-11-29-36CBBB 31 563 8.1 140 4.5 2.4 0.65 91 70 141 21 0.16 0.91 2.5 W 1 2 48W80 D-12-30-2CCAB 28 612 6.5 120 4.7 1.9 1.3 30 65 153 34 0.12 1.27 3.5 W 1 3 49W80 D-1l-30-15CCBA 23 909 8.2 110 10.3 2.9 2.2 143 220 242 22 0.32 0.55 1.05 W 1 4 50W80 D-11-29-10AAAA 25 5408 8.0 1000 9.6 2.2 1.27 1383 655 484 23 0.25 4.18 28 W 1 5 51W80 D-11-29-14AAAA 27 1255 8.9 320 2.2 0.1 0.01 127 295 320 25 0.03 1.82 25 W 1 6 8342 D-13-30-36DDD 41.7 - 9.3 212 0.1 6 1 92 188 120 32 0.146 0.23 18 W 2 7 - D-11-29-36CBB 32.2 550 196 10 0.9 86 154 198 - - - 3.0 W 7 8 - D-13-30-3BDC 33.3 - - 112 - - 15 85 86 62 - - 14.0 W 7 9 - D-13-30-11BCC 32.2 268 - 97 4.5 4.4 8 58 170 - - - 11.0 W 7 10 - D-13-30-14DDD 32.2 267 - 88 8.5 4.8 9 78 122 - - - 7.0 W 7 11 - D-13-30-15DAA 35 289 113 1.8 0.2 12 69 121 - - 0.4 9.9 W 7 - 0 12 D-13-30-30BCB 40 355 - 128 4.0 6.6 13 80 196 6.' W 7 0 - -- - .-I 13 - D-14-31-16DCC 31. 7 293 - 72 22 1.6 6 81 138 31 - - 4.0 W 7 14 - D-14-31-21BCC 32.2 305 7.6 73 20 2.6 14 69 147 51 - - 2.4 W 7 15 319 D-13-30-9AD 33.3 289 :.. 105 3.0 3.9 14 86 127 -- - 14 W 3 16 322 D-13-30-14DD 32.2 267 - 88 8.5 4.8 9 78 147 -- - 7.0 W 3 17 323 D-13-30-15AD 35 285 - 100 6.0 5.2 10 71 164 -- - 12 W 3 18 330 D-13-30-30BC 40 355 - 128 4.0 6.6 13 80 239 - - - 6.8 W 3 19 330 D-13-29-24CD 40.6 31,0 - 128 2.0 4.8 11 67 248 - - - 5.5 W 3 20 AZ18 D-13-31-33AD 26.5 280 7.9 40 2.3 39 2.9 6 67.2 149 41 - 0 1.25 W 5 )/ .•/ Tabl~ 2E. Analyses of Bowie area ground waters Number Sample Location Temperature TDS pH Na K Ca Mg C1 HC0 +C0 Si0 Li B F Remarks Data Source S04 3 2 Na+K 3 1 90 D-12-28-34CCC 37 645 7.9 185 6.9 19 1.5 163 140 80 25 0.3 3.7 2.2 W 1 2 91 D-12-28-27CCC 25 248 8.0 62 1.9 11 1.3 34 115 74 25 0.1 3.7 1.1 W 1 3 92 D-12-28-27BBB 26 334 7.9 70 2.1 19 2.2 68 65 94 26 0.1 4.1 0.9 W 1 4 93 D-12-28-10CCC 35 686 8.0 2.5 3.4 16 0.4 183 115 88 33 0.4 3.7 2.4 W 1 5 20W80 D-'-13-28-10BCCC 37 247 7.7 156 8.9 12.~ 1.8 31 36 191 - 0.5 <.1 <.1 W 1 6 21W80 D-13-28-15DCCCB 35 264 7.7 142 4.3 2.6 0.2 31 26 207 44 0.3 <.1 <.1 W 1 7 22W80 D-13-28-15ADDD 34 492 7.6 166 4.5 3.2 0.3 97 80 177 48 0.4 <.1 2.6 W 1 8 23W80 D-13-28-15BDCDC 35 253 7.4 164 4.1 2.6 0.2 30 23 195 49 0.4 <.1 0.9 W 1 9 24W80 D-13-28- 9BCCC 33 488 7.5 29 3.3 16.6 1.4 86 8 86 37 0.1 <.1 8.0 W 1 10 25W80 D-12~28-26CCDDC 37 496 8.1 28 2.2 14.6 2.4 92 28 93 31 <.1 <.1 7.5 W 1 11 26W80 D-12-28-34BCBBB 37 649 7.3 72 5.9 16.1 1.7 157 112 72 26 0.2 <.1 7.1 W 1 12 27W80 D-12-28-27ABBCC 34 376 7.0 25 2.6 22.0 3.4 44 24 108 33 0.1 <.1 6.8 W 1 13 28W80 D-13-29-25CDDD 37 299 8.4 50 3.1 35.8 8.8 21 4 115 35 <.1 <.1 3.1 W 1 r-l 14 29W80 D-13-29-25CDDD 36 303 8.5 82 5.3 7.7 0.4 22 8 108 36 0.3 <.1 2.2 W 1 0 r-l 15 8290 D-13-29-27ACC 33.3 1020 8.0 113 1 14 2 24 76 210 23 0.08 0.02 2.8 W 2 16 - D-13-28-4DDB 37.2 231 - 57 16 3.2 24 34 126 32 -- 0.8 W 7 17 - D-13-28-9BCC 31.7 402 7.8 69 52 12 63 57 216 40 - - 0.8 W 7 18 - D-13-29-24DCC 41.7 315 - 124 3.0 1.1 12 47 195 - - - 4.0 W 7 19 AZ30 D-12-23-34BC 31 268 8.0 55 2.JJ 22.2 1.9 31.5 61 99 31 - 0.02 0.30 W 5 20 AZ31 D-12-28-34BA 29 424 7.7 77.4 2.7 41.9 6.4 66 79 171 35 - 0.10 0.82 W 5 21 AZ32 D-12-28-34AA 36 392 8.7 113 2.7 7.6 0.2 63 113 89 31 0.17 0.04 1.02 W 5 22· AZ33 D-13-28-10CB 36 256 8.1 49.4 2.7 23.2 2.1 27 57 117 26 - 0.02 0.11 W 5 23 AZ34 D-12-28-10CC 35.5 704 8.1 204 3.5 26 0.4 173 121 117 30 - 0.14 2.17 W 5 24 AZ35 D-11-29-36BB 30.5 2016 7.9 518 6.2 81.1 12.0 175 1026 184 41 - 1.18 4.65 W 5 25 AZ36 D-13-30-'-3DB 23 584 7.9 145 2.0 27.4 8.4 20.5 134 325 61 - 0.22 5.10 W 5 26 AZ37 D-13-30-15 27.5 372 9.3 136 0.8 1.2 0.1 1.8 56.7 212, 25 - 0.18 16.8 W 5 /~.!, 'V Table 2F. Analyses of Whitlock Mountains area ground water Number Sample Location Temperature TDS pH Na K Ca Mg C1 HC0 +C0 S10 Li B F Remarks Data Source S04 3 3 2 Na+K 1 31W80 D-10-28-36ADABA 41 1050 8.1 315 3.5 1.0 0.3 201 260 98 55 0.4 0.55 5.2 I( 1 2 521(80 D- 8-28-22CCBCA 30 985 8.2 260 5.1 1.2 0.12 198 275 168 36 0.4 0.73 12 I( 1 3 - D- 8-28-36AAC 41 --- - - .,. 200 - 195 -- - 11 W 7 4 335 D-10-29-31BB? 41.1 962 - 334 12 7.4 195 301 205 - - - 11 I( 3 5 AZ62 D-10-28-36AD 41.1 960 8.3 351 3.5 6.6 0.4 200 284 192 59 0.48 0.50 9.9 w 5 6 AZ63 D-10-29-20AC 34.1 720 9.0 253 4.3 2.2 0.2 111 207 152 36 - 0.30 4.95 W 5 7 AZ64 D- 8-29-22CAA 30.8 860 8.3 237 9.8 35.8 9.5 184 274 117 45 - 0.24 1.14 I( 5 8 AZ65 D- 8-29-21AB 32.8 1000 8.5 332 5.1 5.4 0.5 190 269 194 59 - 0.44 8.25 W 5 ;:;.N , , -', Table 3A Geothermometers for the Gila Valley-Indian Hot Springs area G E a THE ~ H n HETE R V A LUES NUN9fR S AI-lf'l 1. UV;,\ TION IE HP < RATIP E NA-1(-CA CHALCEDONY aUARTllCONOUCTIVEI ALPHA-CRISIOBALITE ( CI l CI l CI I CI I Cl 1 57 1)',2, 36C81"- 'tf.,.OO 99.09 76.',3 10&.23 55.75 2 5 3H ~') D52~1 Honr. 4b.no 82.'n 66.26 96.5& 4&.28 3 51,''; -:() O')2',17AOOD 45.~0 82.18 "9.42 99.52 49.) 7 4 55"'(1 ~72(, 171\DD9 47.no 7b.05 70.43 100.4& ')0.09 5 lei 7 051Q 7AD 47.PO b IHH 0>;2417AO 40.~0 7 1 i'l.? ll'iU+l7AG 47.flO "- Inll 052417AO 47. PO '! 2~) (}O D/,24 11 Art 58.'10 10 2~" I D7,?411Bfj 10.1)0 It AIt:l f)52417A 47.f)0 101.35 64.51 ')4.92 44.68 12 AlII ')52417A 41>.50 99.82 &4.51 '}4.93 44.68 13 All4 'O/,253bC 43.>;0 70.29 85.22 114.1& 63.58 14 AllI il>;?417AD B.OO 101.93 7"-.21 107.69 57.19 t', A71. ~'J 07/57CCC 29.50 79.16 41.20 74.78 25.16 16 All,!> 07241400 2'i. 5 0 70.90 4 L. 89 73.53 23.9b ('f) o r-l Table 3B. Geotherrnometers for the Buena Vista area G EaT HER ~ n H E TER v A l U E S NUHIl"R SAI"tPlf U)C~TlllN Tri'1pr.~f\TlJ?E NA-K-CA CHAlCEOONY ~UARTl(CllNOUCTIVEI ALPHA-CRISTOAALIIE ( C 1 ( CI ( CI ( C 1 ( CI I ~p. DU7IIAAH 49.no 152.61 82.51 111.67 61.12 2 ~Q 0717 nco ]~.OO ·8R .19 81.118 111.08 60.?4 3 74 Dh772':>00DO ·27.00 BO.43 73.60 103.41 52. 'I'i 4 17 WI\D ll7?7ZAAOC 3h.()O 66.18 40.97 72 .66 23.12 5 1 ?,'-iriC n7Z711~1l~~ '.. *).00 96.P2 48.52 79.84 3C.04 b l'h,;'1() D7272A:JeB ltD.DO 82.81 43.12 74.71 25.0·. 7 30W'\0 !)7Z7ZADDCA J9.00 127.36 AI.11l nO.43 59.90 8 811) 7 D7277 4 ~J. 1 0 67.56 7'1.32 108.71 58.20 .~ QZ7 07272CC 35.hO ------10 ·fJ I ~ 1)7?7I1RBB 41. ~O 90.11 H2.4b 111.&2 bl.!)? 11 All (l lJ 7.7 7Z ACA 37. '0 94.52 83.B3 112.88 02.11 -.::1 o r-l Table 3C. Geothermorneters for the Cactus Flat-Artesia area GEOTHE R 11 f) 11 E T E R VALUE S htU/"l13 [I{ SA"';~)l[ LOCATION T"';oER~ TURE NA-K-CA C~ALCfOUNY OUARTlICONOUCT1VEI ALPHA-CR1STIJRAL1TE ( C I ICI ( CI I Cl ( CI 2~ DqZ'12AAA 31.00 91.44 22.61 54.97 I> .23 21, 1)~7'.7DOA 39.no 85.~2 22.02 54.41 5. /)'1 3 27 OM?~l ~ ~DCC n.oo 9'>.63 15.44 48.00 -0.38 4 zn QP?~20::JBCC 45."0 17.73 . 2 5.46 57.74 B. B& 19 C 11 ~ --) be B ~ Jl.OO 75.55 24.'10 57.20 8.14 " ]3 11~2', 7P~B ··Pt.OO 84.~7 Z6.R~ ')'1.11 10.16 7 14 D~25l?AAA VI.oo 84.2a 31.2 ') 6).33 14.18 9 5(' D'17>lOfJO Jr,.OO 74.79 31.14 6).22 14.08 9 ~) Oq2~ 7ADC 12.00 86.74 20.14 52.58 3.9b 10 54 O"2~7f)OA ]Q.OO 74.22 34. ~2 66.76 17.47 11 55 DQZh 700a 35. () 0 72.27 34.77 66.71 17.41 12 56 D3?~ 7UUg 3a.oo 73.22 16. h 1 68.49 1'1.11 13 75 0~2(>31CCCC Jl.?O 50.45 ~1.4'1 02.66 32. 7~ 14 7f, oeZh3Z0ce 2".00 '10.47 43.34 74.'11 25. Z'I 15 '14 11 QU>1 "IDee R Z 7.0 a 51.57 71.'>8 101.6) 51.23 Ib 15 IJil?"I'ICD?A ?l.00 57.27 6R.50 93.66 41\ .)) 17 96 O~?(, 19CiJOB Z7.00 60.'15 55.26 8b.22 3b.21 le '17 D8lh19CODR ?'1.CO &6.84 52.65 8J.7~ )J.83 11 '1P i)~?I',3]eCO 14.00 6'1.36 41.01 7Z .69 23.1') ZO lO"l il R? ~3lf)C 13.10 ------21 AlLZ 00.1" 700 I'f?OO 84.9) )5.1 'I 67.l2 17.el Z2 ~llJ 'lUh7t9 4'). ;10 80.)2 30.01 62.14 13.04 2J All 7 D~?"lOCO 44.00 91.01 31.08 70.84 21.37 LJ') 24 Anl 08",IOt 41. 50 78.90 41.52 73 .18 23. Cl 0 15 All) IJq2~12A~t 3'1.00 8l. 17 41.67 73. )2 2). 7~ ..-1 16 AU4 [JR2..,7AC 17.00 75.?2 43.45 75.0Z 25.39 27 All') n q ?67f!A )f•• C;O 80.46 34.4) 01,.)'1 17.10 21\ AI,") n~?6 7~->3 33. '>0 72.06 3q.38 70.17 20.73 29 bl Z fi 09?!>5BA 33.00 80.17 42.02 73.65 24.07 )0 All'! r;T?~5~A 33.00 84.97 45.0~ 7b.5,) 26.87 )1 " I')'} [I1\16~CA 3'1.40 81.5'1 34.)4 '>6.30 17.02 A7~O / 32 OA7 l "}BC 1'1.40 c4.'15 47.70 79.06 29.29 .\3 A7'>l OP.?I)q]C 3Q.OO 62.48 10.1>0 02.70 13.58 34 AlII" D811',ZOOC 1'1 .. 40 64.64 37.'19 69.81 20.38 ,'~ "'J' (\"~ ) Table 3D. Geothermometers for the San Simon area GE o THE R H fJ H ET E R VALUES 'fUMBER S ~ MOL I: LOCATION T~11PEP~TU:;E NA-l(-CA CHALCEDONY aUARTZ(CONOUCTIVEI ALPHA-CRISTUBALITE ( CI (CI « CI ( Cl « Cl I' 4lHAG Dll?936CR~ 31.110 92.20 32.71 64.25 15.06 Z 49~30 IH1102CCA'1 Z~ .00 H.07 51.56 64.62 34.bb 3 4q'M~ 0 lJIIHJI5CCa Z3.GO 51.73 33."5 65.9) 16.bb 4 ~OH9!) Olll'llOAAA 25.00 80.61 36.14 ba.03 18.66 , t;111'10 011 ?'Jl4AAA 27.00 215.10 33.36 ti5.3o 16.1J 6 B)'t l Iil1303"DfJO 41.7'") 8.97 21.ilO 54.19 5.4'1 1 f)1l?936CS~ 32.20 ------IJ11303R'iC 33. ·10 ------RJ. () 1 IlZ.12 61.77 "I Cl130119CC V.ZO III OI11:Jl4DfJD 12. Z 0 II CJIJ1(!lSDAA 1~.()0 12 Dll1030BCI\ 40.00 11 !J14l1160CC H.70 ------4'1.4'1 80.7" 30.93 14 OI'o11218CC 32.10 ------7Z.44 102.3J 51.n IS 31° ClnO'}AD 13. 30 10 372 <)1 J IOl4DD 32.10 17 3ll DlJ3015AC 15 ...0 18 310 OIIlOJOBC 41J.()0 l'I no OU2714CV 40. flO ZO Alili DI331BW 2~.<;0 32.35 61.47 n.OA 41.90 \D 0 r-i Table 3E. Geothermometers for the Bowie area G E 0 THE RHO H E T ~ R VAL'JES NUHB ER SA t'PLE LOCATION TEI·PERATU'lE NA-K-CA CHALCEDONY OUARTIICONOUCTIVEI ALPHA-CRISTORALITE I CI I C 1 I CI I CI I CI 1 '10 DIU83~CCC 17.00 9~.~7 19.54 71.29 21.BO 2 '11 DllZ827CCC 25.00 51.91 19.53 71.28 21.79 1 'l? 01ll Rl7B!\q 21,.00 ~7. 7~ ~1. 31 72.93 21.42 ~ 93 DIU~10CCC J5.00 ------51.22 8l.~O 32.51 5 linno D1128109CC 37.00 101.15 ------6 2 1 ~ HO OlllP,I?OCC 15.00 124.17 b?04 95.42 45.10 7 .lZk~1l 0IllRl?AOO 14. 00 122.67 69.40 99.?0 49.1? 8 21HiW {)U~815RDC 15.00 124.19 70.58 100. "0 50.23 ~ 24kAO 01178'JBCCC 33.00 54.62 57.10 87.97 J7.91 10 2?HEO o 122326CCD 37.00 45.49 4B .16 79.50 29.71 11 2&"RO D 122834BCB 31.00 82.42 41.7\> 73.~ 1 23.84 12 l7Wfi0 0122827ABB 14.'10 41.68 52.15 83.2~ 33.37 lJ lOW'tO D_H925COO 37.00 43.85 57.12 B3.2b B.H 14 29H'!'l o 13l925COO )~.IjO 97.28 52.70 83.81 33.87 15 ~lQtl OlJ2927ACC D.30 76.01 36.01 67.91 18.56 1" (] III 94DOB J7.20 ------50.8il 82.09 32.21 17 01llBncc 11.70 ------00.41 91.08 40.91 1,1 01379240CC 41.70 ------19 ADa DllZd34ec 31.00 41.53 4R.54 79.67 30.00 20 A711 01U834RA 2'1.00 H.29 54.42 35.44 35.~5 21 Al37 0122 R34AA 36. ao 76.10 44.11 75.65 26.00 22 AI J:\ 01il~10Cq 36.00 47.79 ~0.72 72.41 22.88 2J AI14 ill77810CC )5.~0 66.66 46.77 78.17 2 8. ~4 l~ H3'J 01l29369R 30."0 90.06 61.41 92.02 ~1.85 r--- l~ Alk fJn3030B 21.00 58.22 0 81.36 110.00 60.0b .--l 2b AZ 17 DLB015 27.')0 78.04 20.46 52.89 4.25 Table 3F. Geotherrnorneters for the Whitlock Mountains area G E 0 THE RHO h f T E R ~ ALUES .... Uh--2 (R SH;PLF LflCATION T<'1PER~TlJPE NA-K-CA CHALCEDONY OUARTI(CONOUCTI~EJ ALPHA-CRISTllnALITE ( CJ ( CI ( CI ( Cl ( CI 1 311-1:30 D If! 7 83bMH 41.110 104.18 7~.C5 104.70 54.31 l <;l"') tl \}e?~2ZCCl.!C 3n.oo 15q.~8 54.h3 85.1>3 35.6" 3 !J~Z;D6H.C 41. GO 4 330, 0IfJZ'HISB "1.10 5 Alb? DI')?~)6AO 41. 10 'J7.23 77 .65 107.17 56.6e 6 A71,) OIoznOAC 34.10 13Z.80 4".~b 76.3b l6.be 7 Al!>" DB2"Z2CAA )o.~o 67.51 64.58 '14.99 4".7't 8 Al ~}'J Dolo2lAB 32.1'0 11'1.78 76.60 IOb.lO 55.73 co o ,.--l Table 4. Summary table showing aquifers in the Cactus Flat area with temperatures and estimated temperature gradients t N I a 5 Miles -- ..... I I I L_..., , IL ;I ~ STUOY~ T8S AREA-"\., 1 I lOS I I IR24E R25E R27E ESTIMATED AVERAGE TEMPERATURE TEMPERATURE TEMPERATURE GRADIENT GRADIENT 1001- ena: 1JJ I 25°C 58.3°Clkm 58.3°Clkm CONFINED A()(JIFER 1JJ ~ :r: Ii: 2001_ 28.9°C -30.O"C 55.8-60.9°C'km 58.4°C/km CONFINED Ar;tJIFER 1JJ CI 29.4°C - 32.8°C 50.9- 64BOClklT 57.9°Clkm COIFINED AQUIFER 300- 35.6°C -35.8°C 54.0-58.eoClkm 56:4°Clkm CONFINED A()(JIFER DIAGRAM SHOWING AQUIFERS IN THE CACTUS FLAT AREA WITH TEMPERATURES AND ESTIMATED TEMP ERATURE GRADIENTS. AQUIFERS DETERMINED BY DRILlERs' COMMENTS DOCUMENTED IN KNECHTEL,I938 109 APPENDIX 1 Selected Drillers Logs 110 Test Hole 0-6-27-35cbb Summary of description of Thickness Depth Core Lithology by E.S. (feet) (feet) Davidson, U.S. Geological Survey, Tucson No Record 560 0 560 Conglomerate, "Dipping 30 129 689 from vertical," Red Granite Clasts "Tertiary" volcanic 3 692 rock and volcanoclastic rock "Laramide" andesite, epidotised, 308 1000 mineralized with copper 0-6-27-35dda Driller's log Thickness Depth Gravel 15 15 Gravel and Caliche 235 250 in alternating 3 foot layers 0-6-27-36ccc Driller's log Thickness Depth Gravel 15 15 Gravel and Caliche in 235 250 alternating 3 feet beds 0-7-27-lbba DrillerI slog Thickness Depth Gravel 15 15 Gravel and Caliche 235 250 in alternating layers 3 feet apart 0-7-27-2aaa Driller's log Thickness Depth Boulders 18 18 Clay 27 45 Sand-water 7 52 Clay 13 65 Clay 7 72 Sandy clay 13 85 Clay 12 97 Sandy clay 8 105 Clay 12 117 Gravel 8 125 Clay 20 145 Gravel and warm water 12 157 Clay 8 165 Gravel and water raised to 12 177 18 feet of top Clay 23 200 Gravel 6 206 Clay 6 212 Boulders and gravel 20 232 Gravel 11 243 Clay 4 247 Gravel 101 348 Clay 9 357 Gravel and clay 43 400 111 D-7-27-2aab2 Driller's log Thickness Depth Brown sand and dirt 16 16 Boulders 8 24 Yellow clay 101 125 Gravel 55 180 Clay 10 190 Gravel, conglomerate 40 330 Yellow clay 20 350 Conglomerate, last 150 500 10 feet hard D-7-27-2aca Driller's log Thickness Depth Top soil 10' 10 Boulders 15 25 OQ U 44 Gravel 8 52 Clay 26 78 Fine sand 6 84 Clay 20 104 Fine sand 5 109 OQ 8 117 Fine sand 6 123 Clay and sand 37 160 Clay and gravel 8 168 Clay 20 188 Sand 6 194 Clay 4 198 Gravel 7 205 Sandy clay 5 210 OQ 6 216 Sand 6 222 Sand and gravel, water flowed 12 234 Clay and gravel 66 300 Sand 9 309 Gravel 11 320 Clay 4 324 Sand and gravel 8 332 OQ 6 338 Gravel and clay 7 345 Clay 15 350 Course sand 4 354 Boulders 12 366 Boulders and clay 21 387 Clay 3 392 Boulders 7 525 D-i-27-2acd Driller's log Thickness Depth Top soil 8 8 Gravel 7 15 Clay 10 25 Sand clay and water 13 38 Clay 7 45 Gravel 7 52 Clay 25 77 Sand and gravel 11 88 Clay 7 95 Gravel 15 110 Clay 3 118 Gravel 7 125 Clay 9 134 Sand and gravel 11 145 Clay 6 151 Gravel and sand 20 171 Clay 13 184 Gravel 16 200 Clay 17 217 Sand and gravel 10 227 Clay 12 239 Sand anc.. gravel 13 252 Clay 10 262 Gravel and boulders 38 400 112 D-7-27-2cdb Driller's log Thickness Depth (feet) (feet) Surface soil 16 16 Boulders 32 48 Yellow clay 82 130 Gravel 12 142 Yellow clay 16 158 Gravel 14 172 Yellow clay 25 197 Gravel 18 215 Yellow clay 7 222 Gravel 15 237 Clay 11 248 Gravel 7 255 Clay 5 260 Conglomerate 41 301 Yellow clay 6 307 Water gravel 108 415 Yellow clay 3 418 Water gravel 84 502 Yellow clay 6 508 Water gravel 27 535 Yellow clay 3 538 Sand and Boulders 22 560 Yellow clay 6 566 Water Gravel and Sand 134 700 Bedrock "Red Granite" 2 702 D-7-27-llbbb(1) Driller's log Thickness Depth (feet) (feet) Boulders 18 18 Clay 24 42 Sand and Water 4 46 Clay and Sand 64 110 Gravel 2 112 Clay and Sand 17 129 Sandy clay 16 145 Clay and Sand 157 302 Sandy clay 37 339 Clay 5 344 Gravel (water flowed) 12 356 Clay 5 361 Sand and Gravel 37 398 Clay 11 409 Sand 7 416 Clay 4 420 Coarse sand 15 435 D-7-27-llbbb(2) (East Well) Driller's log Thickness Depth (feet) (feet) Boulders 22 22 Clay and Water 21 43 Sand 2 45 Clay 28 73 Sand and Clay 8 81 Sand and Clay 210 291 Gravel 4 295 Clay 7 302 Gravel 5 307 Clay 3 310 Sandy clay 28 338 Gravel 9 347 Sandy clay 11 358 Malapai sand 11 369 Clay 5 374 Gravel 6 380 Malapai sand 3 383 Clay 25 408 113 D-7-27-2dbb Driller's log Thickness Depth Water-loam 14 14 Gravel rock 21 35 Rock and clay 10 45 Clay 10 55 Clay and Gravel 20 75 Water Gravel (water at 6 feet 1 76 of top) Clay 29 105 Gravel 7 112 Clay 30 142 Gravel 6 148 Clay 7 155 Gravel 5 160 Clay 6 166 Gravel 3 169 Clay 11 180 Gravel 7 187 Clay 6 193 Gravel 5 198 Clay 12 210 Gravel 22 232 Clay 6 238 Gravel 19 257 Clay 11 268 Gravel 8 276 Clay 6 282 Gravel 5 287 Clay 4 291 Gravel 6 297 Clay 11 308 Gravel 7 315 Clay 7 322 Gravel 5 327 Clay 7 334 Gravel 8 342 Clay 6 348 Gravel flowing water 8 356 Clay 8 364 Gravel 9 373 Clay 8 381 Gravel 12 393 Gravel 40 433 114 APPENDIX 2 pH Correction for the Silica Geotherrnorneters 115 APPENDIX 2 .pH· Correction for·· the·· Silica Geothermometers Dissolved silica (Si(OH)4 concentrations in ground water are largely temperature dependent. Quartz or chalcedony (Si02) is dissolved in water to form the Si(0H)4 species: Equation 1 However, when pH is high, the silica analyzed in the laboratory includes dissociated silicic acid: Equation 2 Si(OH)4 = SiO(OH)a + H+ The~~fore, excess silica introduced by ionization or dissociation of silicic acid must be subtracted from analyzed silica before geothermometer calculations are performed. Such a correction may be called a pH correc- tion since the ionization of silicic acid is dependent largely upon pH. The equilibrium constant (K) for the dissociation of Si(OH) 4 in 9 7 o water is 10- • at 2S oC (29S K): Equation 3 Equation 3 reduces to: Equation 4 -9.70 = 10g[SiO(OH)3J + 10g&+] - 10g [Si(OH)J 116 By converting milligrams per liter to molal concentration of analyzed silica, the silica correction (C ) is: Si02 Equation 5 lOX CSi02 = _s 1.04l6667XlO s where: X = 9.7 + pH + lOg~Analyzed silica) (1.04l6667XlO- 2) An additional refinement to this correction is needed because the dissocia- tion constant (K) varies with temperature. By using the Vanlt Hoff equation, this constant may be calculated at any temperature. The value of heat of ionization (~H) used is 3.3 kcal/mole at 25 0 C. Equation 6 dlnK ~H --=-2 at RT Rewritten as: Equation 7 ~HSdT ~H dInK = InK = - .- = - - + C S S K T2 RT or: Equation 8 ~H log K = - .00458T + C For known values of K, ~H, and T, C is calculated as follows: Equation 9 C = (.Oo~5~)(299) - 9.70 = - 7.30 117 Therefore, the ionization constant at any temperature (oK) is: Equation 10 -720.5 -7.30 K.r= T Thus, a complete pH silica correction for any insitu temperature (oK) may be calculated using milligrams per liter of analyzed silica as follows: Equation 11 1.0416667X10-S where: t-7~0. ~Ana1yzed x = 5J-7.3 + pH + log silica) (1.0416667X10-52J The silica correction value (C ) is subtracted from analyzed silica before Si02 geothermometer calculations are performed. A silica correction for pH may be necessary only for pH exceeding 7.8 and is generally not important until pH exceeds 8.5. 118 APPENDIX 3 Arizona Bureau of Mines Memorandum 119 copy Memorandum to·· Dt"ljI Ohapman SUBJECT I 'I'BIP TO THE SAN SIMON OR Ft1NK WELt. On ju.l1 25. 1940, a.t the invitation of Mr. G. II. Ebeen, Bnd for reasons explained by the attaohed oorrespondenoe, I visited the San Simon or Funk Wolle Upon aniTUg theN I found Mr. Ebsen TOry' willing to turn1ah samples ot drill cores and cuttings and all poatdble information for our reoords, He seemed well plo8.80d that the Arizona Eureau of Mines had responded promptly to hie inntat10n to via1 t the proporty" This well 1s trIO mUos west at San Simon, 200 teet trom the 9 E Gomer. Sec. 27, T.13S., rooE•. The following 1nformation ooncer:n,.... 1118 it was furnished b1 Mr. !J,'b8lJJ1, The drilllng has beont1naneed by sane 1600 people who havD 1n 'fested sums of ~.OO to $100 eaoh. Started in 1928, it hs8 reached a depth ot 6657 teet at a coat of approximatol1 $200,000. S. W. Funk, ot Oharter Oak, Calif., is trustee. Mr. Ebsen suggested that U;r. Funk would gladly furnish the . Arisona Blreau 01' .Mines nth the drillers' log. Until we obtain that 10it we' have the following statements which !l.r. Ebeen took fl'om memory: Valley 1'111 material, eons1st1ng ot more or less firmly oonsoli dated gravel, saud. and s11t. was penetrated fram the eurfsce to a depth of soms"hat mOM than 2000 feet, below whioh stratified sand... atone, oODglomerate, arkose and shale (of ~retaceou8 aspeot) have continued to ,.he bottan of the hole. Abundant artas1an water Was enoountered above the ~retaceOuB, Q~oo1al1y at a dopth ot 1260 feet. In the lowest 200-300 teet of the hole this water haa a temperature 0 of 274, J'. Mr. Ebsonstatas that 011 sand was encountered at 6643-6647 feet. and that gas which burns 10 feet high abavo the collar is produced 4uri~~iVabb1%l£' CONCLUstONS ~ Possibly the 011 sand is genuine, -Qo6 Graph1ta dllS'" !,oeitJ CJoaur in the 8.retaoeoug ot the Chir1aahua rl~ountaina, soma 14 milf'l8 farthor south. On tha other hand, 1t oannot bf3 deniod that such hot water (2740 F) would stew oonsiderable grease off of GOOOfeet ot drill oable. The drill oores given me by Mr. Ebaan arc of rock ot ~etnceaus aspect. Heretofore, W8 had no proot ot the presonoe ot this formation beneath the San Simon Valley. Although this rock 1s not unfavorable, it is 1mpoonible to predict if or where favorable 011 struotures may ex1at in the tretaoeOUB be. neath the valley fill. From a oammaro1al standpoint, the search for oil under such condit~ons 15 a wildoat venture. To be ad.ded later: stayanow1s rSJ)ort on the fossil fragments in tho drill corea. .\lao H!O analysis. 120 BIBLIOGRAPHY Aiken~ C. L. V., 1978, Gravity and aeromagnetic anomalies of southeastern Arizona in Callender, J. E., Wilt, J. C., and Clemons, R. E., eds., Land of Cochise, New Mexico Geological Society Guidebook, 29th field conference, pp. 301-313. Aiken, C. L. V., and Sumner, J. 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