geothermal resource potential of the safford-san simon basin, arizona

asal conglomerate facies of the lower basin fill.
rfuere this occurs, important
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 thickness
of 183 meters.
Correlation of the blue clay unit with the green clay
facies is probable because both "formation" tops occur near the same elevation
and have similar deposition setting.
Also, the lithology of the green
clay facies and the blue clay unit is apparently identical.
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