A lineament map prepared from a mosaic of western Montana shows about 85 lines not represented on the state geologic map, including elements of a northeast-trending set through central western Montana which merit ground truth checking and consideration in regional structural analysis. Experimental fold annotation resulted in a significant local correction to the state geologic map. Photogeologic mapping studies produced only limited success in identification of rock types, but they did result in the precise delineation of a late Cretaceous or early Tertiary volcanic field (Adel Mountain field) and the mapping of a connection between two granitic bodies shown on the state map. Imagery was used successfully to map clay pans associated with bentonite beds in gently dipping Bearpaw Shale. It is already apparent that ERTS imagery should be used to facilitate preparation of a much needed statewide tectonic map and that satellite imagery mapping, aided by ground calibration, provides and economical means to discover and correct errors in the state geologic map

Alt, D. D.

Berg, R. B.

Flood, R. E.

Hawley, K. T.

Johns, W. M.

Wackwitz, L. K.

Weidman, R. M.

English

NASA Technical Reports Server

Paper G 32 
APPLICABILITY OF ERTS-I TO LINEAMENT AND PHOTOGEOLOGIC MAPPING 
I N  MONTANA -- PRELIMINAI~Y REPORT 
Robert M. Weidman, David D. Alt, Raymond E. Flood, Jr., Katharine T. Hc.drey, 
and Linda K. Wackwitz, U3iversit,# of Montana, Missoula, Montana; Richard B. 
Berg, Willis M. Johns, Montana t'ureau of Mines and Geology, Butte, Montana 
ABSTRACT 
P lineament map prepared f r ~ m  a mosaic o f  western Montana shows 
about 85 l i nes  not represented on the s ta te  geologic map, including 
elements o f  a northeast-trending set through central  western Montana 
wkich mer i t  ground t r u t h  checkSng and consiaeration i n  regional struc- 
tura l  analysis. Experimental f o l d  an~lo ta t ion resul ted i n  a s i g n i f  isant 
local  correct ion t o  the s ta te  geolcgic vap. Photogeologic mapping 
studies produced only 1 i m i  ted success i n  i d e n t i f i c a t i o n  o f  rock types, 
but they d i d  r esu l t  i n  the precise del inedt ion o f  a l a t e  Cretaceous o r  
ear ly Ter t iary  volcanic, f i e l d  (Adel Mountaiq f i e l d )  arid the mapping o f  
a connection between two g ran i t i c  bodies shovn on the state map. Imag- 
ery was used successful ly t o  map clay pans asssciated w i th  bentonite 
beds i n  gently dipping Bearpaw Shale. I t  i s  already dpparent tha t  ERTS 
imagery should be used t o  f a c i l i t a t e  preparation cf a much needed 
statewide tectonic map and tha t  s a t e l l i t e  imagery moping, aided by 
g r o u ~ d  ca l ibra t ion,  provides an economical means t o  discover and cor- 
r ec t  errors i n  the s ta te  geologic map. 
TECTONIC MAPFING STUD1 ES 
A 1ineame;tt map for  western Montana !Fig. i) was drawn as an over- 
l a y  t o  a Band 7 mosaic l a i d  d i r e c t l y  from 9-inch p r i n t s  supplied by 
the NASA Data Processing Fac i l i t y .  Most of the mapped lineaments ap- 
pear t o  be topographic expressior,; o f  f rac tu re  (scarps and s t r a i gh t  
canvons); a few are incl ined, res is tan t  s t ra ta .  They range i n  length 
from 8 t o  150 km. Lineaments were checked against the g e o l ~ g i c  map of 
Montana (1  : 5G0,000 scale, koss and others, 1955) and against newly- 
compi led  t e s t  s i  t e  geologi c maps representing approximately one quarter 
of the t o t a l  area covered. More than 50 o f  them appear t o  be h i t he r t o  
unrecognized possible f au l t s  which w i  11 be investigated. Plow some 130 
1 ineaments annotatea, 1 ines o f  northeast t rend are much more coAlnon 
than was ant ic ipated and those o f  northwzst t rend much less so. Shadw 
enhancement aids s ign i f i can t l y  i n  recogni t ion o f  1 ineaments trending I n  
a1 1 direct ions except northwest-southeast. 
Most o f  the impor t tn t  n o m l  f au l t s  i n  the area are represented on 
the lineament map. I n  the area east and nor th  o f  Flathead Lake these 
(;*, - u - . 
, . ' .  ,7 ;,; 33; t e  b, irch~$ed f:", 
-. 
:. ;, , >  ., ... . -,I 
I - .  , , . . I  3r.d bdi\l3t2 Aven!!? 
Falls, SIi 57198 
https://ntrs.nasa.gov/search.jsp?R=19730019531 2020-03-17T08:43:07+00:00Z
tend t o  appear as scarps. I n  southwster.n Montana they mark tne bound- 
a r i es  beween mountain blocks and T e r t i a r y  intermontane basins. Faul ts  
bounding the northeastern and northwestern sides o f  the Ruby Range, the 
west s ide  o f  the Tobacco Root Mountains, and the western f lanks o f  the 
Madison, Gal l a t i n  and Br idger  Ranges are especial l y  good examples. 
Lineaments mapped i n  southwestern Montana from ERTS imagery compare 
we l l  w i t h  f a u l t s  mapped by Bur fe ind  (1967) w i t h  the a i d  of extensive 
geopiysi c a l  work. 
Low angle f a u l t s ,  such as the Lewis ou?r th rus t .  are no t  r e a d i l y  
apparent. Higher angle reverse-s l ip  f au l t s  might be i n f e r r e d  from the 
arcuate pa t te rn  o f  para1 l e l  r idges i n  the Sawtacth Range s t r u c t u r a l  
s a l i e n t  about 75 mi les west o f  Great F a l l s .  
Short. and medi um 1 ength 1 inemtents o f  nor theast  t rend are prominent 
i 7  a broad zone southeast o f  a l i n e  connectirtg Missoula and Great Fa1 1s; 
they appear t o  re?rec,ent a s i g n i f i c a n t  f rac ture  i r e r ~ d  r ~ u i  h i t h e r t o  ap- 
preciated.  One suck lineament def ines the s tca iah t ,  southeast-dipping 
f lank of the L i t t l e  F e l t  u p l ~ f t .  Anothor, fo l lowed by the va l l ey  o f  
t he  L i t t l e  Boulder River, trends toward the stroog!y miner?l  i zoa cni n ina 
d i s t r i c t  a t  Eutte. 
Northwest t rending f a u l t s  z re  d i f f i c u l t  t o  see because of t h e i r  
o r i e n t a t i o n  para1 l e l  t o  the i 11 umination d i rec t i on .  An exception i s  
the Shroder Creek f a u l t ,  c l e a r l y  v i s i b i e  on ERTS imagery as a l i n e r v e n t  
extending 17 mi les west from Flathead Lake, bu t  mapped w i t h  considerable 
d i f f i c u l t y  by LaPcint (1971), w b 7  showed t h a t  i t  has undergone one t o  
two mi les o f  r i g h t  s l i p .  
Of s i x  prominently v i s i b l e  west-trending 1 ineaments crossing the 
Kootenai R iver  Canyon i n  extreme northwestern h n t a n a ,  none are shown 
as fau l t s  on the s t a t e  geologic map and or,ly the soathernmcst two on 
the ; :125,090 scale geologic map (Johns, 1970). Two minor s.hocks re-  
corded by the Libby Dam seismic network i n  August, 1972 have been r e f e r -  
red  t o  epicenters a1 ong these 1 ineaments (personal comnunication, 
G i I J  H. Crosby, Un ive rs i t y  o f  Montana). 
Rather d e t a i l e d  mapping o f  f o l d s  i n  d i f f e r e n t i a l l y  eroded Pale- 
ozoic and Mesozoic s t r i i t a  i s  poss ib le  f o r  arcas o f  moderzte r e l i e f  
and scanty f o r e s t  cover. Study o f  t he  area between the  Clkhorn and 
Crazy Mountains ind ica tes  t h a t  the  low sun angle imagery o f  Novem- 
ber  (1106-17465-7) i s  much b e t t e r  f o r  such mapping than t h a t  taken 
i n  August. Ridge pat te rns  o f t e n  a i l ow  de l i nea t i on  of plunging fo lds 
w i t h  wave lengths o f  a few ki lometers; r e s o l u t i o n  o f  a x i a l  t races 
1.6 km. apar t  i s  possib le.  Land form i n d i c a t i o n  o f  d i p  d i r e c t i o n  
a l lows i d e n t i f i c a t i o n  o f  f o l d  type a t  sca t te red loca t ions .  The most 
successful f o l d  mapping u t i  1 i zed  1 : 500,000 sca le  enlargessnts under 
overlays and a t  2r magni f i ca t ion  under t he  zoom t r a n s f e r  sco9e. 
Annotat ion o f  a plunglt ig f o l d  p a i r  zuggests a s i g n i f i c a n t  co r rec t i on  
t o  t he  s t a t e  geo iog ic  map t o r  nnse p a t t e r n  and t rend,  i n v o l v i n g  a 
s h i f t  o f  an a x i a l  t r a c e  by as much as 2.6 km. 
PHOTOGEOLOGIC MAPPING STUDIES 
E f f o r t s  t o  develop c r i t e r i a  f o r  photo1 i t t i o l og i c  recogni  t-I on o f  
rock  t y ~ e s  and rock un ' t s  f r c n  EkTS imagery have met w i t h  l i m i t e d  
huccess. I t  i s  poss ib le ,  v i t h  some ass is tance  f rom ground t r u t h  
i n f o m a t i o n ,  t o  d e l i n 2 a t e  t h e  boundaries o f  c e r t a i n  ma jo r  rock  bodies, 
i n c l  ud jng  those o f  Cenozoic bas'n f i 11 , upturned Paleozoi  c  and 
Mesozoic s t r a t a ,  and t he  igneous rock  bodies d iscussed below. 
Large vo l zan i c  p i l e s  a r e  d i s t i n c t i v e  i n  ESTS imagery because c f  
t b p i  r t ~ n a l  qual i ty,  t he?  r l a c k  o f  s t r o n g l y  apparent i n t e ~ , n a l  geo log ic  
s t r u c t u r e  cr s t r u c t a r a l l y  c o n t r o l  l e d  dra inage pa t t e rns ,  and t h e i r  
tendency t o  bury  s t r u c t u r e s  ev i den t  i n  ad jacen t  oldsr rock;. The 
Adel Mountain vo l  cani  cs , o f  l a t e s t  Cretacsous o r  e a r l  i e s t  T e r t i a r y  
age, were successfu l l .y  de l i ned ted  w i t h  o n l y  m inor  dooar tures from 
t h e  o u t l i n e s  s h o ~ n  on pub l i shed  maps, as were s a t e l l i t s  l a c c o l i  t h s  t o  
t h e  n o r t h  (F i g .  2 ) .  Four t opog raph i ca l l y  expressed d i kes  i n  a  swarm 
e x t e n d i q  nor thward f rom t h e  main body o f  v o l c a r ~ i c s  were recognized even 
though t h e ?  r th icknesses a r e  w e l l  below r e s c l u t i o n  1 i m i  t s .  Other  l a r g e  
vo l can i c  p i l e s  i n  wes :ern Montana, such as t h e  E l  khorn Mountains and 
Lowland Creek f ie;ds, a r e  l e s s  apparent,  b u t  the  l a t t e r  was mapped 
w i t h  cons iderab le  success. O u t l y i n g  areas o f  s t r u c t u r a l l y  deformed 
E l  khorn Mountsins vo l can i cs  were n o t  recognized i n  imagery. 
Large g r a n i t i c  ba tho l  i ths ,  such as t h e  Bouyder b a t h o l i  t h y  a re  
moderate ly  d i s t i n c t i v e  i n  ERTS i l i l ager j  because of t h e i r  i n t e rmed ia te  
t ona l  qua l  i ty, l a c k  o f  apparent  i n t e r n a l  geo log i c  s t r u c t u r e ,  and s t r c n g  
tevdeilcy f o r  c o n t r o l  o f  dra inage p a t t e r n s  by f r a c t u r e  se ts .  Sma l le r  
g r a r ~ i  t i c  i n t r u s i o n s  a re  more r e a d i l y  apparent  through t h e i r  s t r u c t u r a ?  
e f f e c t  on t he  coun t ry  r ock  than chrough any d i s t i n c t i v e  qual  i t y  i n  t h e  
appearance c f  t h e  i n t r u s i v e  r ~ c k  i t s e l f .  E f f ~ ~ t s  t o  d e l i n e a t e  t h e  
~ ~ t l  ines  o f  ba tho l  i t h i c  i n t r u s t o n s  o f  g r a n i t e  i n  t h e  Pioneer  Mountains 
l e d  t o  a  map (F ig .3)  showing bo th  s t r ong  c o r r e l a t i o n s  and ma jo r  depar t -  
ures f rom t he  o u t l  i nes  shown on t h e  s t ~ t e  geo log i c  map. Both t h e  
c o r r e l a t i o n s  and t h e  depar tures a r e  be l i e ved  t o  be s i g n i f i c a n t  and 
t h i s  area w i l l  be examined du r i ng  t h e  coming f i e l d  season. 
Small g r a n i t i c  s tocks  and 1 acco l  i t h i c  i n t r u s i o n s  o f  a1 k a l  i n e  
rocks  a re  numerous i n  severa l  p a r t s  o f  t h e  area covered by o u r  imagery. 
These t end  t o  draw a t t e n t i o n  t o  themselves through t h e i r  da rker  t ona l  
qual i tj, a m a t t e r  of v e g e t a t i v e  cover  r a t h e r  than o f  r ock  tone, b u t  
o t h e r  c r i t e r i a  make them d i s t i n c t i v e .  Laccol  i t h s  no rma l l y  e x h i b i t  
ci:.cular o u t l  i nes  and domal form, whether o r  no t  t h e i r  igneous cores 
a r e  exposed. Upturned edges o f  sedimentary beds a long  t h e  f l a n k s  o f  
b c t h  l a c c o l i  t h s  and g r a n i t i c  s t ocks  a r e  c l e a r l y  ev i de i i t  i n  ERTS imagery. 
BEARPAW SHALE BENTOhITE STUDv 
The p o s s i b i l i t y  o f  recognizing Bearpaw Shale known t o  conta in 
benton i te  beds o f  economic p o t e n t i a l  was i r v e s t i g a t e d  f o r  an area on 
the  f lanks  o f  the Ingomar a n t i c l i n e  where ground t r u t h  i s  we1 1  krlokn 
(Berg, 1970). The area i s  about 130 km northeast  o f  B i l l i n q s .  
Using a  1/500,000 scale negative p r i n t ,  an over lay flap (F ig .4)  was 
drawn t o  show h i g h l y  r e f l e c t i v e  zreas o f  i r r e g u l a r  pa t te rn  as w e l l  as 
a  continuous tonal  boundary thought t o  represent a  1 i t l lo log ic  contact .  
The i -esul ts  were compared t o  a  ground t r u t h  map and l a rge  scale a e r i a l  
photographs covering most o f  the benton i te  deposits iq the area. 
Known benton i te  exposures i n  the area are too small t o  be 
recognized d i r e c t l y  i n  the  ERTS i m g e r y ,  bu t  the i r r e ~ u l  a r  r e f l e c t i  vc 
patches may be a  c lue  t o  t h e i r  occurrence. These areas o f  h igh 
r e f l e c t i v i t y  are s u r f i c i a l  c l ay  pans, mud-fi 1  l e d  channels and 
depressions, t h a t  develop on the Bearpaw Shale where dips dre less  than 
3 degrees and benton i te  beds we l l  exposed. Further  work may show 
t h a t  areas of h igh r e f l e c t i v i t y  can be used f o r  recoqn i t ion  c f  those 
areas w i t h i n  the Bearpaw Shale where benton i te  beds are exposed. 
CONCLUSIONS 
ERTS imagery i s  p o t e n t i a l i y  a  major t o o l  f o r  improving geologic 
knowledge o f  Montana. Lineament mapping ha: d l  I-eady successful 1  y 
i d e n t i f i e d  prev ious ly  unmapped f a u l t s  and emphasized the  importance 
o f  nor theast- t rending f rac tures .  Experin~ental anrd ta t ion  o f  f o l d s  
has demonstrated t h a t  imagery may be usec' t o  co r rec t  e r ro rs  i n  t rend 
and l o c a t i o n  o f  a x i a l  t races i n f e r r e d  from the  s t a t e  geologic map. 
S a t e l l i t e  imagery should be used t o  expedite preparat ion o f  a  much 
needed tec ton i c  map of t he  e n t i r e  s t a t e  a t  a scale as l a rge  as 
1:500,000. Use o f  imagery f o r  t e c t c n i c  mapping should r e s u l t  i n  
s i g n i f i c a n t  saving i n  t ime and money, as w e l l  as j d e n t i f i c a t i o n  of 
p rev ious ly  unmapped f a u l t s .  A probable b01 i2~  would be the extensidn 
o f  known f a u l t s  and the recogn i t i on  o f  pa t te rns  f?r qhor ter  1 ineaments 
important  t o  reg iona l  s t r u c t u r a l  ana lys is .  
Pho to l i  t ho log i c  recogn i t i on  o f  a t  l e a s t  some major rock u n i t s  i s  
poss ib le  w i t h  the  help o f  l i m i t e d  ground t r u t h  i n f o r m ~ t i o n .  De l in -  
ea t i on  o f  t h e i r  boundaries as expressed i n  ERTS imagery should lead 
t o  s i g n i f i c a n t  ref inement o f  the s t a t e  geologic map. 
REFERENCES 
Berg, R.B., 1970, Bentonl t e  deposl t s  I n  the Ingomar-Vananda t rea,  
Treasure and Rosebud Counties, Montana: Montana Bureau o f  
M I  nes ana Geology Spec. Pub. 51, 
Burfelnd, W.J., 1967, A g r a v i t y  l nves t l ga t l on  o f  the Tobacco Root 
Mountalns, Jef ferson Basln, Rourder bath01 i th,  and adjacent 
areas o f  southwestern Montana: urlpubl . Ph.D. th,?sls, Dept. o f  
Geology, Indfana Unlv. 
Johns, W.M., 1970, Geology and mlners l  deposits o f  L inco ln  acd 
Flathead Count1 es, Montbna: Montana Bureau o f  M I  nes and 
Geology, B u l l .  79. 
LaPoint, D. J.', 1971, Geology and geophysics o f  thr. southwesitrn 
Flathead Lake reglon, Montana: unp~S1 . Master's thesis,  Dept. 
o f  Geology, Unlv. o f  Montana. 
Ross, C. P., -Andrews, D.A. and W l  t k lnd ,  I .J., 1955, Geologic Fap o f  
Montana: U.S. Geological Survey. 
Hachured 1 ines represent scarps. P l a i n  1 ines show s t r a i g h t  canyons. 
--LL known f a u l t  s p e c i f i c a l l y  recognized as imagery lineament 
. - - - ' - ' o  1 ineament n o t  represented on s t a t e  o r  t e s t  s i t e  geologic maps 
_ _ - - inc l ined,  r e s i s t a n t  s t r a t a  
Fig. 1. Preliminat-y ERTS-1 lineament map o f  western Montdna, drawn 
o r i g i n a l l y  a t  1:1,000,000 scale on over lay of Band 7 mosaic fo r  l a t e  
August, 1972. # - Missoula, Bu - Butte, Bc - Bozeman, H - Helena, 
G - Great Fa l ls ,  KR - Kootenai River, CF - Clark Fork o f  Columbia, 
FR - Flathead River, FL - Flathead Lake, MR - Missour i  River, YR - 
Yellowstone River. 

'
 (S- L6ZLL-5801) 
luaUa6Jelua ale3s 000'00S : ; 
UO
JJ 
uM
eJa 
'
a
~
~
q
s
 
M
edJeaa 
ub 
spaq alkuoJuaq 
Q
L
M
 paqe!3osse 
sued Ke!D 
pue 
a
~
o
~
 
au
oqspues 
6u!~oqs auk[3!que 
~
e
w
o6u1 40 deu 
~
J
J
~
~
U
I
I
 
.b 
-6bj 
aleq
s 
~
e
d
~
r
a
u
 
4
0
 
a
s
eq 
b (ss) 
u
o! ~
e
w
~
o
j 
\ 
-
.
.
 
b
 
\' 
J
~
A
!
U
 ql!p
n
r 40 
do1 
,
 
,
 
:
~
~
e
l
u
o
~
 
q1nJl p
u
n
o
lu
' 
-
 
A
lepunoq 
1 ru
o
a
 
~
1
~
3
 
,
+
\.-,O
 
A
Jabew
! 
W
J) 
s
u
ed A
el3 
aA
!l=
al,al 
~
lq
b
!r( 0
 


Applicability of ERTS-1 to lineament and photogeologic mapping in Montana:  Preliminary report

Applicability of ERTS-1 to lineament and photogeologic mapping in Montana: Preliminary report

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server