Gemini 4 color photo interpretation for Gulf of California and central Texa

Drewes, H.

English

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NATURAL RESOURCES 
PROGRAM^
SPACE APPLICATIONS 
PROGRAMS
TECHNICAL LETTER NASA
U.S. Geological Survey 
Department of the Interior
L3.74
https://ntrs.nasa.gov/search.jsp?R=19700029659 2020-03-11T22:50:00+00:00Z
«***.#%tjt',«>5
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UNITED STATES 
DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY 
Washington, D 0C 0 20242
Dr. Peter Co Badgley
Chief, Natural Resources Program
Office of Space Science and Applications
Code SAR, NASA Headquarters
Washington, DoC.'20546
Dear Peters
Transmitted herewith are 3 copies of:
TECHNICAL LETTER NASA-46
AN EVALUATION OF THE GEMINI IV COLOR PHOTOS
:    
Technical Letter 
NASA-46 
October 1966
OF THE GULF OF CALIFORNIA ^QE
' '
by
Ho Drewes**
.TEXAS, AREA*
Sincerely yours,
William A« Fischer 
Research Coordinator 
Earth Orbiter Program
*Work performed under NASA Contract No* R-09-020-013 
o Geological Survey, Denver, Colorado
TO:
HMD RESEARCH REFERENCE 
USGS NATIONA 
RESTON, VA
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UNITED STATES 
DEPARTMENT OF THE INTERIOR 
GEOLOGICAL SURVEY
TECHNICAL LETTER NASA-46
AN EVALUATION OF THE GEMINI IV COLOR PHOTOS 
OF THE GULF OF CALIFORNIA - CENTRAL TEXAS AREA*
by
Ho Drewes** 
October 1966
These data are preliminary and should 
not be quoted without permission
Prepared by the Geological Survey
for the National Aeronautcis and
Space Administration (NASA)
*Work performed under NASA Contract No. R-09-020-013 
**U.So Geological Survey, Denver, Colorado
Photo copies of illustrations are available for viewing at the 
following places:
Author(s); Discipline Coordinators; NASA Data Bank (Houston), Remote 
Sensing Evaluation and Coordination Staff (RESECS) and the U.S. 
Geological Survey Libraries (Denver, Menlo,. Washington, Flagstaff).
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DISTRIBUTION LIST
NASA Headcusrters. D.C.
Miss V/innie Morgan, Technical Reports Officer 
Dr. Peter C. Badgley, Program Chief 
Theodore A. George
NASA/MSC-Houston '  
Leo F. Childs, Chairman, Aircraft Coordination 
Ed Zeitler, Data Center
Authors 
v 
USGS A/ashing ton
William T. Pecora 
Research Coordinator 
Remote Sensing Evaluation and 
Coordination Staff (RESECS) 
Chief Geologist 
Associate Chief Geologist 
Assistant Chief Geologists (4) 
Chief Hydrologist 
Chief Topographic Engineer 
Discipline Coordinators (4) 
Jules MacKallor 
William Hemphill 
Alien Heyl 
Robert Moxham 
Alan Kover 
David Southv/ick 
Isidore Zietz 
Stephen J. Gav;arecki 
Washington Library 
Denver Library 
Menlo Library
USGS/Menlo Park
Ernest H. .Lathram 
Hal T. Morris 
Robert E. Wallace 
Edward W. Wolfe 
George Gryc 
Max Crittenden 
Parke Snavely, Jr.
Copies
1
20
10
Copies USGS/Denver
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Arthur B. Campbell
Robert L. Christiansen
David F. Davic'son
Ross B. Johnson
Daniel R. Shawe
Robert H. Morris
Tom Hendricks
USGS/Flagstaff
Gerald S. Schaber
US Dept. of Agriculture
A.B. Park
 US Air Force
J.F. Cronin (AFCRL)
US Navy
A.G. Alexiou (NAVOCEANO)
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Other Coooeratina Investigators Cocies
R.N. Colwell, Univ. Calif
J. Lintz, Univ. Nevada
R.J.P. Lyon, Stanford Univ.
D.B. Simonett, Univ. Kansas
E.H.T. Whitten, Northwestern
 William Vest, IITRI, D.C.
NAS/NRC Advisory Comm. Chm.
j1 j .
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1 :1 :
Univ. 1
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CONTENTS
Page 
  Tucson area ........................................ 1
Pinacate volcanic area ............................. 3
El Paso area 
Evaluation .
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An evaluation of the Gemini IV color photos 
of the Gulf of California - Central Texas area
by 
H. Drewes
On the Gemini IV mission a series of overlapping photographs 
were taken June 5, 1965, from the Gulf of California to central 
Texas. These photos have a limited value as an ale!.'to geologic 
mapping. Their chief value to geologic interpretation lies in 
their fine definition of surficial deposits and some younger 
volcanic rocks. They also show, in a much less reliable way, 
some kinds of older sedimentary and igneous rocks, and show a 
little of the geologic structure of the region. The photos in 
Texas are oblique shots, which sufficiently distorts large 
portions of the photos to impair their value as a geologic tool. 
A large amount of cultural detail can be identified in areas 
with which I am familiar; they include roads, small reservoirs 
and fence lines.
Three areas were selected for review to illustrate what 
geologic interpretations can be made of different geologic 
terrances and what interpretations can be made of areas with 
which I am familiar to various degrees. I shall first review 
an area (Fig. l) of mixed rock types near Tucson, Arizona, 
with which I am most familiar. Next I will evaluate the Pinacate 
volcanic area (Fig. 2), about which there is a little published 
information and finally, an area southwest of El Paso, Texas, 
(Fig. 3) which I know practically nothing, and try to apply there 
some of the guides to rock types learned in the first 2 areas,
Tucson area   Photos 9 (Fig. 1) and 10 of Magazine 8 center 
about the Santa Rita Mountains in which I have been mapping the 
geology for 3 years. On the photos Nogales lies near the southern 
edge; Tucson lies along the northern edge, and the Santa Cruz 
River flows between them. Reference will be made to the Sierrita 
Mountains, sputhwest of Tucson, and to the Rincon, Whetstone and 
Huachuca Mountains, located along the eastern edge of the photos, 
in that order from north to south.
A familiarity with the area helps considerably in interpreting 
the culture and vegetation of this area. Towns are the most con- 
spicuous cultural features. Linear objects such as roads and : 
railroads can only be seen in some places, perhaps those in which 
the reflectivity of the road metal contrasts with that of the 
adjacent areas. For example, the new interstate h'ighwayv southeast',; 
of Tucson escapes detection, but the equally new 2-lane highway
east of the Whetstone Mountains shows up clearly. Fields, both 
fallow and cultivated, and mine dumps and tailings ponds are 
conspicuous features south and southwest of Tucson. Fence lines 
appear east northeast of the darkest (highest) part of the Santa 
Rita Mountains as short straight north-trending breaks between 
lighter-and darker-colored patches, which are pastures th£t have 
been grazed different amounts (Fig.l). The large dark areas in 
the mountains are oak and evergreen forests, which commonly are 
sufficiently dense to seriously interfere with the geologic 
interpretation of photos taken from lower altitudes.
Several types of surficial deposits can be delineated by 
their color and drainage texture. The deepest reddish-brown 
areas in which the drainage density is low are underlain by a 
thin sheet of gravel of roughly mid-Pleistocene age on which a 
soil has been well developed. Lighter-brown areas with a finer 
drainage texture are underlain by younger gravels, and the gray 
areas with the finest pattern of anastomosing drainages are the 
youngest deposits on which the amount of soil developed is 
inconsequential. Gravel or semiconsolidated conglomerate of 
late Tertiary to early Pleistocene age makes a fine herringbone 
pattern, as southeast of the highest part of the Santa Rita 
Mountains and the northwest flank of the Whetstone Mountains.
Areas underlain by older bedrock give more trouble, at 
least partly because the rock types are complexly mixed. Moderate- 
ly young (mid-Tertiary) rhyodacite volcanics underlie the 
irregularly mottled area southwest of the Santa Rita Mountains 
and in most of the low mountains northwest of Nogales. Other 
younger volcanics of more basic composition underlie the dark 
patch between Tucson and the northermost mine tailings. Some 
areas underlain by granitic rocks can be recognized by their 
uniform light-gray color and moderately regular fine-grained 
drainage pattern, as in the core of the Sierrita Mountains, and 
much of the northern end of the Santa Rita Mountains. In a few 
small areas Paleozoic sedimentary rocks underlie light bluish-gray 
areas but elsewhere these and other older rocks, the Mesozoic 
volcanics and the metamorphic rocks are not readily recognized.
Since many of the large structural features involve older 
rocks, it is not surprising that these features are obscure. The 
strong lineation along the west flank of the Huachuca Mountains 
and extending across the north-central part of the Santa Rita 
Mountains is largely fault-controlled. The small area of linear 
pattern on the west flanks of the Sierrita Mountains is made up 
of upened metamorphic rocks. The ridges on the west flank of the 
Rincon Mountains resemble, and are, gently westward plunging 
anticlines, in this case in metamorphic rocks.
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Pinacate volcanic area   Photos 4, 5 and 6 of Magazine 8 
cover a little-studied young volcanic area in northwestern Sonora,. 
Mexico. Puerto Pefiasco lies at the prominent hook-shaped point 
of land in the Gulf of California, and Mexico Hwy. 5 cuts across 
the northeast corner of Photo 5 (Fig. 2) close to the U.S. border. 
The Pinacate volcanic area underlies the dark-gray roughly ellip- 
tical area covering slightly more than the central ninth of the 
photo. Much-subdued mountains are scattered north and east of 
the volcanic field but .most of .the area around the field is 
veneered with surficial deposits.
A variety of surficial deposits such as aeolian, beach, and 
tidal deposits can be recognized on this photo, in addition to 
those described in the Tucson area. Constructional geomorphic 
features such as dunes and beach and submarine bars stand out 
plainly, as they do in all aerial photos. The medium-gray area 
with the straight eastern margin east of the northwest corner of 
the photo may be a playa surface, darkened either by a phreatophyte 
vegetation or a dark clay. The straight eastern margin suggests 
fault control.
The uniform light-gray color and fine drainage texture 
suggest that the hills north and east of the volcanic field are 
largely underlain by granitic rock.
The rocks of the Pinacate volcanic field include a small 
amount of very young lava flows, possibly of basic composition, 
shown as black patches, and a large amount of pyroclastic material 
(and possibly weathered older flows), shown in medium-dark gray. 
Cinder cones appear as small dark-gray spots abundantly scattered 
over the northern half of the volcanic field. At least 7, and 
possibly 12 large craters or calderas appear in the northeast half 
of the field, and some of them contain cinder cones. A few calderas 
have been mapped and illustrated by low-^altitude oblique aerial 
photos by R. H. Jahns (1959, p. 165^184) in the Arizona Geological 
Society, Guidebook II.
El Paso area   The third area to be described lies west-southwest ' 
of El Paso and is covered by Photos 16, 17 and 18 of Magazine 8. The 
playa, Ojo De Los Mosquitos, Mexico, forms the white patch near the 
center of Photo 17 (Fig. 3) and the Tres Hermanos Mountains, New 
Mexico, form the dark range along the right side of the upper edge 
of the photo.
Applying the lessons learned in the other two areas examined, 
3 ages of alluvium, beach, playa, and dune deposits can be delineated. 
A large medium-gray area of younger volcanics lie east-northeast of 
the playa on the photo, and on the east side of this field there may 
be an east-trending row of cinder cones and perhaps a crater. The 
core of the Tres Hermanos Mountains may be granitic rock. The 
relatively subdued-looking light-gray ridges north and northwest of
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the playa are underlain by one type of sedimentary rock that strikes 
northwestward; the sharper dark-gray ridges east and southeast of the 
playa are underlain by another type of sedimentary rock that strikes 
dominantly northwestward but is folded T These two types of sedimen- 
tary rocks may be separated by a major structural or stratigraphic 
break that is not observable on the photos. A hill southwest of the 
playa contains a northwest-trending linear feature that truncates 
beds, and thus may be a fault.
Evaluation   Two aspects of the Gemini IV color photos ought 
to be evaluated separately, their very high altitude, and their 
color. Seeing the surface of the earth from such great heights - 
about 100 miles - gives the advantage of seeing at a glance a large 
area relatively free of distortion due to topography. However, 
this advantage seems to be a geographic rather than a geologic one, 
for few of the major structural features known in southeastern 
Arizona and probably also present in Mexico, can be seen on the . 
photos. In no place was a dip direction on bedded rocks observed. . 
Too few subdivisions of bedrock types can be made reliably to. 
enable me to jmake a reconnaissance geologic map comparable to 
the kind expected of Survey geologists today. In all fairness, 
I should add that the 1:20,000 aerial photos available in the 
Santa Rita Mountains are not too satisfactory for photogeologic 
mapping either, because the rocks there are not "photogenic" and 
the structure is complex. Under these circumstances I think 
1:10,000 photos may be more useful than 1:500,000.
A little more can be done with a photogeologic interpretation 
of surficial deposits and of young volcanic fields, but part of 
this is due to the color aspect of the photos rather than the high 
altitude at which they were taken. In fact, I suspect that their 
great altitude is actually a handicap, for a far smaller range of 
color values appears in the Gemini photos than I have seen in some 
low-altitude colored aerial photos of a nearby region. Very likely 
the atmosphere preferentially filters out some wave-lengths of 
light.
Since the potential geologic value of these photos seem to be 
greatest in areas of little eroded volcanics and of surficial de- 
posits, and presumably, in places where atmospheric interference 
is low, I expect such photogeologic efforts on the surface of the 
moon to be more useful than on the earth.
I would be curious to see the film negatives, rather than 
prints of the photos to see whether more detail is preserved.
°T*^^u.

3


An Evaluation of the Gemini 4 Color Photos of the Gulf of California-central Texas Area

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