UNITED S T A T E S DEPARTMENT OF THE INTERIOR

GEOLOG lCAL SURVEY WASHINGTON. D.C. 20242 Technical L e t t e r

NASA -24 May 1966

D r . Pe t e r C. Badgley Chief , Natural Resources Program O f f i c e of Space Science and Appl ica t ion Code SAR, NASA Headquarters Washington, D.C. 20546

Dear Peter :

Transmit ted herewith a r e 3 copies of :

TECHNICAL LETTER NASA-24

PHOTOGEOLOGIC INTERPRETATION OF GEMINI I V

COLOR PHOTOGRAPHY: BAJA, CALIFORNIA*

S ince re ly yours , .?

William A. F i scher Research Coordinator f o r USGS/NASA Natural Resources Program

*Work performed under NASA Cont rac t No. R-09-020-015 **U.S. Geological Survey, Menlo Park, ~ a f i f o r n i a

UNITED STATES

DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

TECHNICAL LETTER NASA -24

PHOTOGEOLOGIC INTERPRETATION OF GEMINI I V

COLOR PHOTOGRAPHY: BA J A , CALIFORNIA*

Rowland Tabor**

May 1966

These d a t a a r e p r e l i m i n a r y and shou ld n o t be quo ted w i t h o u t pe rmiss ion

Prepared by t h e G e o l o g i c a l Survey f o r t h e N a t i o n a l A e r o n a u t i c s and

Space A d m i n i s t r a t i o n (NASA)

*Work performed under NASA C o n t r a c t No. R-09-020-015 **U.S. G e o l o g i c a l Survey, Menlo Park , C a l i f o r n i a

DISTRIBUTION LIST

NASA F ieadqua r t e r s , D.C. C o p i e s

Miss Winnie Morgan, T e c h n i c a l R e p o r t s O f f i c e r D r . P e t e r C. Badg ley , Program Ch ie f Theodore A . George

NASA/MSC-~ous t o n

Leo F . C h i l d s , Chai rman, A i r c r a f t C o o r d i n a t i o n Ed Z e i t l e r , Data C e n t e r

A u t h o r s

u ~ ~ S / ~ a s h i n q t o n C o p i e s U S G S / D ~ ~ V ~ ~

W i l l i a m T. P e c o r a Resea rch C o o r d i n a t o r Remote S e n s i n g E v a l u a t i o n a n d

C o o r d i n a t i o n S t a f f (RESECS) C h i e f G e o l o g i s t A s s o c i a t e C h i e f G e o l o g i s t A s s i s t a n t C h i e f G e o l o g i s t s (4 ) C h i e f H y d r o l o g i s t C h i e f Topograph ic E n g i n e e r D i s c i p l i n e C o o r d i n a t o r s ( 4 ) J u l e s MacKal lor Wi l l i am Hemphi l l A l l e n Hey1 R o b e r t Moxham Alan Kover David Southwick I s i d o r e Z i e t z S t e p h e n J. Gawarecki Washington L i b r a r y Denver L i b r a r y Menlo L i b r a r y

U S G S / M ~ ~ ~ O Pa rk

E r n e s t H. La thram Hal T. M o r r i s R o b e r t E. Wal l ace Edward W. Wolfe George Gryc Max C r i t t e n d e n P a r k e S n a v e l y , Jr.

A r t h u r B. Campbell R o b e r t L. C h r i s t i a n s e n David F. Davidson Ross B. Johnson D a n i e l R . Shawe R o b e r t H. M o r r i s Tom H e n d r i c k s

G e r a l d S . Schabe r

k D e p t . o f A q r i c u l t u r e

A.B. Pa rk

US A i r F o r c e

J . F . C r o n i n (AFCRL)

US Navy

A.G. A lex iou (NAVOCEANO) 1

1 O t h e r Cooperatinq C o p i e s 1 1 R.N. C o l w e l l , Univ . C a l i f 1 1 J. L i n t z , Un iv , Nevada 1 1 R.J.P. Lyon, S t a n f o r d Univ . 1 1 D.B. S i m o n e t t , Univ . Kansas 1 1 E.H.T. W h i t t e n , N o r t h w e s t e r n Univ. 1

W i l l i a m V e s t , I I T R I , D.C. 1 NAS/NRC Adv i so ry Comm. Chm. 1

PHOTOGEOLOGIC INTERPRETATION OF GEMINI I V

COLOR PHOTOGRAPHY: BA J A , CALIFORNIA

Rowland Tabor

I n t r o d u c t i o n

The c o l o r photographs from Gemini I V were t a k e n w i t h a hand h e l d Hasse lb lad camera w i t h a f o c a l l e n g t h o f 8 0 mm ( f 2 . 8 ) . The space v e h i c l e was abou t 180 m i l e s above t h e s u r f a c e o f t h e e a r t h when p a s s i n g o v e r Ba ja , C a l i f o r n i a and t h e pho tograph ic p r i n t s , used i n t h i s s t u d y , have a s c a l e o f abou t 1:640,000.

The photograph s e l e c t e d f o r t h e s t u d y ( f i g . 1 ) i s e s s e n t i a l l y v e r t i c a l , h a s no obscur ing c louds and i s c e n t e r e d o v e r a d e s e r t a r e a i n B a j a , C a l i f o r n i a . Geologic f e a t u r e s a r e w e l l d i s p l a y e d .

Making t h e I n t e r p r e t i v e Map

Convent ional photogeologic methods were employed t o c o n v e r t t h e photograph i n t o a g e o l o g i c map ( f i g . 2) . The major rock u n i t s were t r a c e d d i r e c t l y from t h e photograph, b u t t h e i n t e r p r e t a t i o n was made w i t h a s t e r e o p a i r under m a g n i f i c a t i o n .

E v a l u a t i o n o f t h e I n t e r p r e t a t i o n

The w r i t e r h a s no s p e c i f i c knowledge of t h e geology of Ba ja , C a l i f o r n i a , and t h e u n i t s were named a f t e r comparing t h e i n t e r p r e t i v e map w i t h t h e Geologic Map of North America ( s c a l e 1:5,000,000 1965 ed . ) and a g e o l o g i c map by C.H. Beal (Geol. Soc. AmericaMemoir31, p l . 1, 1948) . P.B. King o f t h e U.S. Geolog ica l Survey i d e n t i f i e d t h e Aqua Blanca f a u l t on t h e photograph. According t o t h e r e f e r e n c e maps t h e g r o s s p i c t u r e o f young v o l c a n i c rock o v e r l y i n g t h e e a s t e r n edge o f a g r a n i t i c h igh land i s c o r r e c t . The c o l o r i n g , s t r a t i f i c a t i o n and r u b b l y wea ther ing d e b r i s s t r o n g l y s u g g e s t t h e p r e s e n c e o f t h e v o l c a n i c r o c k s and t h e mass iveness , j o i n t i n g and c o l o r o f t h e g r a n i t i c rocks g i v e c l u e t o t h e i r i d e n t i t y , Because t h e s t r u c t u r a l s u r f a c e i s s t i l l p r e s e n t l o c a l l y on t h e r e d v o l c a n i c r o c k s , some t e c t o n i c s t r u c t u r e s can be i d e n t i f i e d .

The s t e e p l y d i p p i n g bedded rocks a r e no t shown a t a l l on t h e r e f e r e n c e maps, b u t Beal i n d i c a t e s bedded sed imenta ry rocks a r e p r e s e n t i n t h e o u t c r o p a r e a shown a s g r a n i t i c on t h e n o r t h edge o f t h e map, j u s t wes t o f t h e Colorado River .

Explanat ion 1. Wind blown sand (minor alluvium) 2. Alluvium. Inoludes l i t t e r a l marine sediments i n Gulf area.

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i++ r ' *'-;T: 3. WhLte s u l f a t i r ed volcanio rock o r in t rus ive rook. + 3 a * + + ;

[?T:+m 4. Dark roloanio rook. Generally o v ~ j r l l e e red roloanio rock but i n ;::4:> ::, Ll-rL,Ll area t o eas t , age r e l a t i o n s unknovm.

5. Red voloanio rock, l o c a l l y ooarsely jointed. Underlain by t h i n white rn *ufC (?I .

I 6 . Grey gran i to id rook, ooarsely jointed.

7,8. Steeply dipping layered rooks, e i t h e r sedimentary o r metamorphlo* 7 l i g h t ooZoredj 8 dark oolored.

S t s l k e and d i p Faul t dint i n FOP^ axis in vo%oanic rock grankt oid rook