Evidences of active and ancient Volcanism on Mars. A review (*)

Evidences of active and ancient Volcanism on Mars. A review (*)

P.

HÉDERVÂRI (**)

R e c e i v e d 011 M a y 1 9 t h , 1972

SUMMARY. — S i n c e t h e e n d of t h e l a s t C e n t u r y s o m e o b s e r v a t i o n s c o n cerning flare-phenomena o n M a r s w e r e r e p o r t e d b y d i f f e r e n t e x p l o r e r s . Acc o r d i n g t o t h e o p i n i o n of H e u s e l e r ( u . 1 2 . 1 3 ) , K a t t e r f e l d ( " ) , S a h e k i ( 16 ), S a t o ( 16 ) a n d o t h e r a u t h o r s , t h e r e s p e c t i v e l i g h t - p h e n o m e n a m i g h t h a v e b e e n t h e s i g n s of a c t i v e v o l c a n o e s on t h e p l a n e t . G r e y c l o u d s , o b s e r v e d b y J a p a n e s e e x p l o r e r s a s well a s b y C a p e n ( 3 ), m a y b e also a t t r i b u t e d t o v o l c a n i c o u t b u r s t s . T h e r e a r e s o m e o b s e r v a t i o n s , c a r r i e d o u t b y D o l l f u s ( 10 ), w h i c h r e v e a l e d t h e e x i s t e n c e of r e l a t i v e l y s m a l l , w h i t e , p e r s i s t e n t c l o u d s o v e r cert a i n M a r t i a n r e g i o n s w h i c h c a n b e i n t e r p r e t e d as w h i t e v a p o u r - c l o u d s e m i t t e d b y Martian volcanoes. T h e a u t h o r of t h e p r e s e n t s t u d y h a s i n v e s t i g a t e d t h e d i s t r i b u t i o n of these phenomena over the Martian surface and found t h a t t h e distribution is n o t r a n d o m . T h e e v e n t s o c c u r r e d — in t h e o v e r w h e l m i n g m a j o r i t y of t h e c a s e s — 011 a r e a s w h i c h a r e l y i n g a l o n g t h e t r a n s i t i o n a l r e g i o n b e t w e e n d a r k and bright territories. I t is i m p o r t a n t t o n o t e t h a t m a n y of t h e l u n a r t r a n s i e n t e v e n t s ( p r o b a b l y p o s t v o l c a n i c p h e n o m e n a ) h a v e a s i m i l a r p o s i t i o n 011 t h e l u n a r s u r f a c e , t h a t is t h e y c a n b e f o u n d m o s t l y a t t h e b o r d e r of l u n a r c o n t i n e n t s or b a s i n s r e s p e c t i v e l y . On t h e o t h e r h a n d t h e m o s t i m p o r t a n t v o l c a n i c z o n e s of t h e E a r t h a r e also t o b e f o u n d a l o n g t h e e d g e s of t h e P a c i f i c basin.

(*) P a p e r p r e s e n t e d a t M o n t r e a l on t h e M e e t i n g " N e w A p p r o a c h e s t o P l a n e t o l o g i c a l P r o b l e m s " , A u g u s t , 1972, on t h e o c c a s i o n of 1st P l e n a r y Session of t h e I n t e r n a t i o n a l A s s o c i a t i o n of P l a n e t o l o g y a t t h e I G C . (**) P . R . A . S . , P r e s i d e n t of I n t e r n a t i o n a l L u n a r S o c i e t y , V i c e - P r e s i d e n t of I n t e r n a t i o n a l A s s o c i a t i o n of P l a n e t o l o g y . I I . A r p â d f e j e d e l e m u t j a 40-41, IV/3, B u d a p e s t , H u n g a r y .

482

I\

HÉDERVÀRI

RIASSUNTO. — Sin d a l l a fine del secolo scorso diversi r i c e r c a t o r i riferirono di f e n o m e n i di luci i n t e r m i t t e n t i d a loro o s s e r v a t e su M a r t e . Sec o n d o il p a r e r e di I l e u s e l e r (".12.«), K a t t e r f e l d (14), Salieki ( 15 ), S a t o ( 16 ) ed a l t r i a u t o r i , t a l i segni l u m i n o s i p o t e v a n o significare l ' e s i s t e n z a sul pian e t a di v u l c a n i a t t i v i . A n c h e le n u b i grige, o s s e r v a t e d a ricercatori g i a p p o nesi, o l t r e c h e d a C a p e n ( 3 ), p o s s o n o essere a t t r i b u i t e ad eruzioni vulcaniche. A l t r e osservazioni, f a t t e d a Dollfus ( 10 ), r i v e l a v a n o l'esistenza di n u b i b i a n c h e , p e r s i s t e n t i , r e l a t i v a m e n t e piccole, s o p r a c e r t e zone m a r z i a n e c h e si p o s s o n o i n t e r p r e t a r e q u a ' i e m a n a z i o n i b i a n c h e di v a p o r e , p r o v e nienti d a v u l c a n i m a r z i a n i . L ' a u t o r e di q u e s t o s t u d i o h a e s a m i n a t o la d i s t r i b u z i o n e (li tali fenom e n i s o p r a la superficie di M a r t e ed ha t r o v a t o che essa n o n è a v v e n u t a a casaccio. I f a t t i si sono verificati, nella s t r a g r a n d e m a g g i o r a n z a dei casi, in zone s i t u a t e l u n g o l a fascia di t r a n s i z i o n e t r a i t e r r i t o r i scuri e quelli chiari. In p r o p o s i t o è i m p o r t a n t e n o t a r e che m o l t i e v e n t i l u n a r i t r a n s i t o r i , p r o b a b i l m e n t e f e n o m e n i p o s t - v u l c a n i c i , o c c u p a n o u n a posizione a n a l o g a sulla superficie della L u n a , cioè si t r o v a n o s o p r a t t u t t o ai confini dei contin e n t i o dei b a c i n i l u n a r i . D ' a l t r a p a r t e , a n c h e le zone v u l c a n i c h e p i ù imp o r t a n t i della T e r r a si t r o v a n o l u n g o i b o r d i del b a c i n o del Pacifico.

American, spacecraft Mariner—9 as well as a Soviet one f r o m t h e series of recent Mars-rockets h a v e revealed a t least two small areas on t h e p l a n e t ' s surface where the local t e m p e r a t u r e of t h e g r o u n d is higher with some 10 degrees t h a n in their p r o x i m i t y . I t seems to be logical to suppose t h a t these relatively " h o t " regions represent areas where active solfatara-fields exist. On t h e basis of t h e photos, m a d e b y t h e Mariners one can suppose t h a t in ancient times as well as in t h e recent "geological" p a s t t h e volcanic activity h a d a n i m p o r t a n t role in t h e development of t h e M a r t i a n crust a n d surface. Some i m p o r t a n t a n d interesting features were discovered a m o n g t h e m ringmounts, which are v e r y similar to t h e terrestrial calderas of collapse-origin. T h e terrain inside one of these M a r t i a n calderas has a n a p p e a r a n c e of a typical lava-flow. I t is i m p o r t a n t to n o t e t h a t some flares a n d grey as well as small persistent white clouds a p p e a r e d on areas where r i n g m o u n t s a n d caldera-like f o r m a t i o n s can be f o u n d . F u r t h e r m o r e small volcanic chains parallel with a tectonic chasm, little holes with a diameter of 1 k m or even smaller (probably volcanic v e n t s f r o m which gases escaped), meandering valleys (by all probability r e m n a n t s of u n d e r g r o u n d lava-tubes), a n d last b u t not least cracks in t h e M a r t i a n crust, similar in a p p e a r a n c e to t h e linear eruptions of Iceland were recognized.

E V I D E N C E S OF ACTIVE AND ANCIENT VO LOAN ISM ON MARS. A R E V I E W

HISTORICAL

483

BACKGROUND

According to D a v i d o v (6) t h e first a s t r o n o m e r who observed a flare on Mars was J . M. Ofiord in 1896. F u r t h e r earlier observations were m a d e b y P . Lowell (in 1900 a n d 1903); G. F o u r n i e r a n d Y. F o u r nier (1911); 1ST. P . B a r a b a s h e v (1924), a n d S. M a y e d a (1937). I n m o r e recent times two R u s s i a n experts also m a d e similar observations, n a m e l y V. P . Bedenko a n d A. P . Ivutireva (1956). The first t h e o r y concerning t h e possibility of volcanic eruptions on Mars was developed b y E . M. Antoniadi. Observing t h e Deucalionis Region of Mars in 1909 a n d in 1911, lie perceived grey clouds above it a n d on this basis he supposed t h a t t h e r e are active volcanoes on t h e planet. I n t h e years 1954-55-56 D. McLaughin wrote some papers dealing with t h e similar problem a n d supposed t h a t t h e M a r t i a n volcanoes are to be f o u n d first of all in t h e bay-like f o r m a t i o n s of t h e surface of Mars. His ideas generally were rejected b y other astronomers.

FLARES

The M a r t i a n flares are sudden a n d short-lived light-phenomena usually in white or yellowish-white colour. Their life-time generally is only some minutes. Their brightness o f t e n is r a t h e r strong; sometimes t h e y are as b r i g h t as t h e white polar caps of t h e Mars, sometimes t h e y are even brighter. As regards t h e i n t e r p r e t a t i o n of these p h e n o m e n a , Saheki (15) wrote as follows: " I would like to explain these p h e n o m e n a as t h e sudden developm e n t of white clouds of moisture b r o u g h t a b o u t b y r a p i d u p w a r d curr e n t s in t h e a t m o s p h e r e due to v e r y complex local meteorological phen o m e n a over these limited areas, or else to t h e r a p i d development of clouds of moisture p r o d u c e d b y t h e g r e a t force of active volcanoes which erupt intermittently ". W e collected all the d a t a available a t t h e present t i m e a n d compiled a list (Table I), p r o b a b l y t h e m o s t complete one ever published in this respect. The sources of d a t a a b o u t M a r t i a n flares were as follows: Capen (3), Heuseler ("), K a t t e r f e l d (14), Saheki (15) a n d Sato (ir>),

484

P.

HÉDERVÁRI

r e s p e c t i v e l y . A n e v e n t , o b s e r v e d o n J a n u a r y 6, 1 9 6 1 , a n d r e p o r t e d

by

E . E . B o t h in « T h e Strolling A s t r o n o m e r » , Vol. 15, No. 3-4, w a s also inc l u d e d i n t o t h e l i s t , a l t h o u g h t h e t r u e n a t u r e of t h e o b s e r v e d m e n o n is n o t c l e a r

TABLE

Date

pheno-

enough.

Observer and telescope

I

Location

on

Mars

Remark

1937 06 07

S. M a y e d a ,

8" refi.*

Close t o S i t h o n i u s L a cus, + 55°, 240°

1

1951 12. 08

T. Saheki,

8" refi.

W e s t e r n p o r t i o n of equatorial Titlionius Lacus

2

1954 07 01

T. Saheki,

8" refi.

Edom Promontorium (at t h e e q u a t o r )

3

1954 07 23

T. Saheki,

8" refi.

Mare Acidalium, SW p a r t , + 35°, 42°

4

1954 07 24

C. M c C l e l l a n d , 13" r e f r . * *

Edom

Promontorium

5

1958 11 05

S. M u r a y a m a

8" r e f r .

S o u t h of T a n a i s P l a t e a u , S W e d g e of A p h r o d i t e M a r e (Ac i d a l i a ) , + 35», 42»

6

1958 11 06

s. Tanabe,

3,{5" refi.

Titlionius Lacus, Southern edge

7

Solis L a c u s , N E

1958 11 10

s. F u k u i ,

part

8

1958 11 21

T. Saheki,

8" refi.

N o r t h e r n e d g e of Hellas a n d E d o m P r o montorium

9

1958 1 1 21

I. Tasaka,

13" refi.

N o r t h e r n e d g e of H e l las and E d o m Promontorium

10

1960 10 08

T. Saheki,

8" refi.

U t o p i a R e g i o n , + 50°, 255°

11

1961 01 06

N. Schneller

?

Northern polar cap

12

1967 03 20

S. M i y a m o t o

12" r e f r .

A r c a d i a a n d N e i t h Regions

13

1967 04 21

S. M i y a m o t o

12" r e f r .

Hellas

14

1967 05 0 5

S. M i y a m o t o

12" r e f r .

Nix

15

* refr. = ** refi. =

10" refi.

refractor reflector

The remarks are to be found in Table II.

Olympica

E V I D E N C E S O F A C T I V E A N D A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

Table Serial n u m b e r

485

II Remark

1

Considerably brighter t h a n t h e polar cap and the while clouds. F l i c k e r i n g like a s t a r , a n d a f t e r 5 m i n u t e s it w a s h i d d e n f r o m view (possibly d u e t o r o t a t i o n of the planet)

2

B r i g h t e r t h a n t h e n o r t h p o l a r c a p . F l i c k e r i n g light a n d stellar b r i g h t n e s s of t h e 0 t h m a g n i t u d e f o r 5 m i n u t e s . I t t h e n b e g a n t o be e x t i n g u i s h e d a n d c h a n g e d i n t o a g r a y i s h cloud h a v i n g a d i a m e t e r of m o r e t h a n 300 k m . T h e e n t i r e p h e n o m e n o n l a s t e d a b o u t 40 m i n u t e s

3

I n 10 s e c o n d s t h e colour c h a n g e d f r o m a w h i t i s h - y e l l o w t o a b r i g h t , p u r e w h i t e , a n d t h e n c h a n g e d t o yellowi s h - w h i t e . D u r a t i o n of t h e flare w a s 5 seconds

4

F r o m t h e 23rd, J u l y t o t h e 3 r d , A u g u s t , 1954, m o r e small, v e r y b r i g h t clouds w e r e o b s e r v e d on t h e a r e a w h e r e — a c c o r d i n g t o M u r a y a m a (see n° 6) — a small b u t b r i g h t s p o t occurred

5

F l a r e w a s visible f o r a b o u t 58 seconds. In t h e opinion of t h e o b s e r v e r , it w a s c a u s e d b y a volcanic e r u p t i o n

0

S m a l l b u t v e r y b r i g h t s p o t , w h i t e in colour. L a s t e d about 5 minutes

7

B r i g h t n e s s as s a m e as f o r t h e p o l a r c a p f o r 4 m i n u t e s

8

B r i g h t n e s s s a m e as f o r t h e p o l a r c a p f o r 5 m i n u t e s . Diam e t e r of t h e s p o t is e s t i m a t e d t o be a b o u t 250 k m

9

Two bright spots

10

T h e s a m e s p o t s as a b o v e , (see n° 9). Yellowish-white clouds over t h e N o r t h e r n p a r t of Hellas. B o t h flares l a s t e d a b o u t 5 m i n u t e s , t o g e t h e r w i t h p h a s e s of increase a n d decrease in b r i g h t n e s s : 15 m i n u t e s . A f t e r several m i n u t e s , t h e flares r e a p p e a r e d . T h e o b s e r v a t i o n of S a h e k i a n d T a s a k a h a d t a k e n place on t h e s a m e n i g h t , h o w e v e r n o t in t h e s a m e h o u r . T h e y w o r k e d q u i t e i n d e p e n d e n t l y f r o m each o t h e r . W h e n T a s a k a b e g a n his own o b s e r v a t i o n , S a h e k i a l r e a d y finished his one. T h e d i s a p p e a r a n c e of t h e flares lasted only a b o u t 10 minutes.

11

Small spots, similar in b r i g h t n e s s t o t h a t of t h e p o l a r c a p . W h e n t h e first s p o t d i s a p p e a r e d t h e r e h a d b e e n a p a u s e l a s t e d a b o u t 8 m i n u t e s , a f t e r w h i c h a n e w one a p p e a r e d j u s t on t h e s o m e p o s i t i o n

12

T h i s is a v e r y d o u b t f u l o b s e r v a t i o n

13

Two short-lived white spots

14

Short duration

15

T h r e e w h i t e s p o t s of s h o r t d u r a t i o n

48(>

P.

ÍIÚDERVÁRI

OBJECTIONS

D a v i d o v (6) has pointed out t h a t m a n y of the flare-observations can be interpreted b y other w a y as well. According to h i m t h e b r i g h t p a t c h e s "could h a v e been a directed reflection of solar rays f r o m a cloud of ice crystals in t h e Martian atmosphere, giving a parhelic halo. Alternatively, t h e directed reflection could h a v e been in principle produced b y reflection f r o m a nearly vertical surface s i t u a t e d u p o n t h e p l a n e t itself. T h e short d u r a t i o n . . . would be explained b y t h e planet's rotation". 1 )e Vaucouleurs ( 7 ' 8 ) is on t h e opinion t h a t t h e observations, m a d e m o r e t h a n t e n years ago "were not real; a t the t i m e r e p o r t e d for t h e observations t h e side of Mars t u r n e d t o w a r d t h e E a r t h was not t h a t which was depicted by t h e observer. F u r t h e r m o r e , t h e a p p a r e n t d i a m e t e r of Mars was much too small a n d the telescope a p e r t u r e insufficient to show the a m o u n t of detail represented b y t h e sketches". T a k i n g these objections — especially t h a t of De Vaucouleurs — into consideration, we m u s t proceed v e r y cautiously in the j u d g e m e n t of t h e n a t u r e of these p h e n o m e n a . F o r instance events n u m b e r e d as 7 a n d 12 are d o u b t f u l since in t h e first case the a p e r t u r e of t h e telescope was very small a n d in t h e second case t h e d a t a of t h e i n s t r u m e n t is not given. However there are some factors which are in f a v o u r of the reality a t least of a p a r t of t h e observations. Thus: events, n u m b e r e d as 2 a n d 7, f u r t h e r m o r e as 4 a n d 6 were observed b y two persons who were working independently f r o m each other. According to t h e m the p h e n o m e n a occurred almost on t h e same place of t h e M a r t i a n surface. These events h a d t a k e n place in different years. E v e n t s 9 a n d 10 were observed also b y two i n d e p e n d e n t explorers during t h e same night. The position of t h e respective spots was t h e same. On t h e other h a n d t h e r e are factors which agree with t h e volcanic hypothesis. N a m e l y events signed by n u m b e r 15 (three spots) occurred in t h e Nix Olympica Region a n d Nix Olympic» b y all probability is a gigantic caldera of collapse origin. According to our knowledge t h e volcanic a c t i v i t y can s t a r t again inside t h e caldera after t h e collapse-process (e.g. K r a k a t a u , Santorin, etc.). F u r t h e r m o r e , t h e flare, observed b y Saheki on the 8th, December, 1951, h a d been followed immediately b y the development of a large grey cloud over t h e same point. Accepting t h e theory, explained b y D a v i d o v («), this p h e n o m e n o n would be quite incomprehensible. B u t accepting t h e volcanic theory, the cause of this

E V I D E N C E S O F A C T I V E AND A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

487

F i g . 1. - D i s t r i b u t i o n s of flares, i n d i v i d u a l g r e y clouds, a g r e y s t r e a k , s m a l l p e r s i s t e n t w h i t e clouds a n d t h e five k n o w n c a l d e r a s on Mars. L e g e n d : © flares; A grey clouds; — t h e gray streak; ^ small p e r s i s t e n t w h i t e c l o u d s ; O calderas; + 1 an a d d i t i o n a l flare; t h e e x a c t location of w h i c h is n o t k n o w n b u t it occurred inside Hellas; > 2 t h e n u m b e r of flares on t h e r e s p e c t i v e s p o t w a s g r e a t e r t h a n t w o b u t t h e e x a c t n u m b e r is n o t k n o w n ; 3 t h e r e (at t h e N i x O l y m p i c a Region) t h e o b s e r v e d n u m b e r of white sports was three. T h e m a p is d u e t o D e V a u c o u l e u r s ; t h e d a t a in figure were compiled a n d d r a w n b y t h e a u t h o r u s i n g t h e d a t a of t h e scientists m e n t i o n e d in t h e t e x t .

T>. JIÉDERVÀRI

488

p h e n o m e n o n is clear: one can assume t h a t t h e flare was t h e consequence of a white vapour-cloud e m i t t e d b y a M a r t i a n volcano while t h e grey cloud a f t e r it m i g h t h a v e been a volcanic ash-one.

F i g . 2. - S m a l l p e r s i s t e n t c l o u d s o v e r P r o t e i , P y r r h a e a n d Opliir R e g i o n s . A b o v e : S e p t e m b e r 2 a n d 30, 1950. B e l o w : O c t o b e r 4 a n d 8, 1956. A f t e r D o l l f u s .

Finally, as a f u r t h e r a r g u m e n t in f a v o u r of t h e volcanic n a t u r e of some of M a r t i a n p h e n o m e n a , we can refer to t h e other greyish clouds as well as to t h e small persistent white clouds. These f e a t u r e s will be briefly discussed later.

DISTRIBUTION

OF FLARES

L e t us now accept as a working-hypothesis t h a t t h e flares really can be a t t r i b u t e d to volcanic activity. I n this case it seems to b e interesting t o investigate t h e distribution of these p h e n o m e n a on t h e surface of t h e Mars (supposing t h a t their position was given correctly by


489

t h e observers) a n d to t a k e a comparison with t h e distribution of lunar t r a n s i e n t p h e n o m e n a (which can be r e g a r d e d as postvolcanic events) as well as t h a t of t h e terrestrial volcanic areas. Most of t h e events occurred in areas which are lying along the transitional region between d a r k a n d b r i g h t territories of t h e M a r t i a n landscape. A r a t h e r similar distribution can be experienced in the

F i g . 3. - S m a l l p e r s i s t e n t clouds over E d o m R e g i o n . On t h e l e f t side: S e p t e m b e r 7 a n d O c t o b e r 8, 1956. On t h e r i g h t side: O c t o b e r 12 a n d 13, 1956. F i r s t d r a w i n g b y J . F o c a s ; o t h e r s b y D o l l f u s .

case of small persistent w h i t e clouds a n d of individual grey clouds as well. I t is interesting to n o t e t h a t m a n y of t h e flares a n d clouds occurred in bay-like f o r m a t i o n s as it was supposed b y McLaughlin. As we know, McLaughlin expressed his opinion purely on theoretical base. I n some cases flares h a d t a k e n place i n t h e area of Hellas, which can also b e r e g a r d e d as a n exceptionally large ring-like f e a t u r e s (caldera of collapse origin?).

490

P.

1IÉDERVARI

The lunar transient p h e n o m e n a — in their overwhelming m a j o rity — are s i t u a t e d a t t h e edges of t h e large basins of the Moon (2- 5 ). On t h e other h a n d t h e m o s t i m p o r t a n t active volcanoes of t h e E a r t h can also be f o u n d along t h e edges of the basins. I t seems t h a t this distribution is a n a t u r a l law valid for t h e terrestrial-type p l a n e t a r y bodies. T h e zones of weakness, which are f a v o u r a b l e for volcanic

F i g . 4. - T h e s m a l l w h i t e c l o u d s of E d o m , i n d i c a t e d on a m a p , m a d e b y t h e p h o t o s of M a r i n e r s G a n d 7.

activity developed first of all on areas, lying between basins a n d continental-like regions.

SMALL PERSISTENT WHITE CLOUDS

J . Focas a n d A. Dollfus observed small white clouds located above E d o m Region (September 7, October 8, 12 a n d 13, 1956), f u r t h e r m o r e above P r o t e i a n d P y r r h a e Regions a n d Ophir (September 2, 30 - October


491

4, 8, 1956) 1 0 . These bright, white clouds of small a p p a r e n t size were isolated features in t h e M a r t i a n a t m o s p h e r e a n d generally r e m a i n e d above t h e same locality. Some of t h e m were a r o u n d 100 k m in diam e t e r ( 9 ). T h e one above E d o m a p p e a r e d on each d a y with a new shape. Smallsized, bright clouds, remained fixed in position were seen

F i g . 5. - G i g a n t i c c a l d e r a - l i k e f o r m a t i o n on t h e M a r s ( f r a m e 11. of t h e series of M a r i n e r - 4 p h o t o s ) .

a t Nix Olympica Region as well, which is — as it was m e n t i o n e d above — a caldera of collapse origin. I t m a y be t h a t t h e respective small persistent clouds are of volcanic origin, n a m e l y tliay are white w a t e r - v a p o u r clouds w i t h o u t volcanic ash a n d dust. The a u t h o r h a d d r a w n t h e m onto a detailed m a p

492

P.

IIÉDERVÂRI

of t h e Sinus Meridani — E d o m — Sinus Sabaeus — Deucalionis Regions. T h e respective m a p was m a d e on t h e basis of Mariner-photos (Mariners 6 a n d 7), a n d t h e M a r t i a n r i n g m o u n t s were indicated on it. W e experienced t h a t two of t h e four clouds had been in direct connec-

F i g . 6. - T h e Nix O l y m p i c a Region is m a r k e d b y an a r r o w on t h i s Mariner p h o t o .

tion w i t h r i n g m o u n t s in t h a t meaning, t h a t t h e y a p p e a r e d j u s t over t h e walls of these rings. The t h i r d cloud was located between three small craters. I n t h e case of the f o u r t h cloud t h e r e was no a n y connection with ringmount-formations. Burgess (x) h a s reported, t h a t " b y t a r g e t i n g Mariner — 9's cameras a t k n o w n areas of white clouds, p r o j e c t scientists discovered four m a j o r calderas, w i t h which t h e y seem to b e associated. T h e y could arise

E V I D E N C E S OF A C T I V E A N D A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

27

F i g . 7. - A detailed plioto-mosaic of N i x O l y m p i c a c a l d e r a ( M a r i n e r - 9 p h o t o ) . T h e a r e a inside t h e o b l i q u e f r a m e c a n b e seen in an enlarged f o r m on F i g . 8 ( a f t e r Scientific A m e r i c a n ) .

]>.

4!>4

IlEDEKVAIil

f r o m a f t e r n o o n c o n d e n s a t i o n of v o l c a n i c g a s e s e m i t t e d d u r i n g t h e d a y . Alternatively the clouds could be general atmospheric analogous to those over E a r t h ' s high mountains.

F i g . 8.

condensations

I n the former inter-

A p a r t of Nix O l y m p i c a ' s i n t e r i o r : w e can see a t y p i c a l lava-flow ( a f t e r Scientific A m e r i c a n ) .

p r e t a t i o n t h e c l o u d s w o u l d b e p o s i t i v e e v i d e n c e of c o n t i n u i n g v o l c a n i c a c t i v i t y o n t h e p l a n e t " *. (*) C a p e n (4) liad t h e k i n d n e s s as t o call t h e a u t h o r ' s a t t e n t i o n t o t h e followings: " C e r t a i n light a r e a s do show b r i g h t l y each M a r t i a n m o r n i n g as if t h e w h i t e s u b s t a n c e is d e p o s i t e d d u r i n g t h e cold M a r t i a n n i g h t . This a c t i v i t y h a s been e x p l a i n e d as a t m o s p h e r i c seasonal a c t i v i t y . However, it is q u i t e possible t h a t s o m e of t h e s e w h i t e areas a r e d u e t o volcanic o u t gassing w h i c h is f r o z e n o u t on t h e s u r f a c e as f r o s t each n i g h t . S u c h a r e a s as Opliir, T h a r s i s , N i x O l y m p i c s ; N i x L u x , etc., are s u s p e c t s .

E V I D E N C E S O F ACTIVE AND A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

495

P i g . 9. - T e r r a c e - l i k e s t e p s in t h e N o d u s Gordii c a l d e r a of Mars. Photo m a d e b y M a r i n e r - 9 . D i a m e t e r of c a l d e r a is a b o u t 110 kin.

Concerning this point, we m a y m e n t i o n t h a t also according to Burgess (»): " M a r s ' several m a j o r volcanic areas m u s t h a v e been active in geologically recent times because their lava flows are almost free of i m p a c t craters. Nix Olympica a n d t h e three d a r k spots associated with N o d u s Gordii, Biblis Pons, a n d Gigas, together with Elysium f o r m m a j o r centres of volcanic activity on t h e p l a n e t " .

490

P. IIÉDEKVÂKI

G R E Y CI.OUDS AND GREY STRIPES

There are some indications concerning t h e existence of grey clouds a n d stripes of such grey f o r m a t i o n s in t h e a t m o s p h e r e of t h e Mars. These clouds differ v e r y much f r o m t h e wellknown other clouds a n d therefore a new i n t e r p r e t a t i o n seems to be necessary for their origin.

F i g . 10. - Tn o r d e r t o c o m p a r i n g w i t h F i g . 9: a c a l d e r a a t H a w a i i ( a f t e r S c i e n c e e t Vie).

As it was m e n t i o n e d in t h e i n t r o d u c t i o n of t h e p r e s e n t p a p e r , t h e first explorer, w h o h a d a n o p p o r t u n i t y to observe grey clouds on t h e Mars, was Antoniadi. On t h e 15th, J a n u a r y , 1950, T. Saheki perceived a gigantic grey cloud over E r i d a n i a a n d Electris. T h e d i a m e t e r of t h e f o r m a t i o n was e s t i m a t e d to be a b o u t 750 k m . F u r t h e r observations were m a d e b y E b i z a w a on t h e 29th, March, 1960 (southeastern p a r t of M a r e Sirenum), b y Saheki on t h e 8th, December, 1951 (as it was mentioned earlier, a f t e r a flare over t h e W e s t e r n p o r t i o n of Tithonius Lacus;

E V I D E N C E S O F ACTIVE A N D A N C I E N T VO LOAN ISM ON MARS.

A REVIEW

31

t h e d i a m e t e r of t h e cloud was a b o u t 300 k m a n d S a h e k i was able to observe it d u r i n g a b o u t 40 minutes); b y S. E b i z a w a again between March a n d May of 1962 (over E r i d a n i a a n d Mare Cimmerium; m o r e exactly speaking: on t h e c o m m o n border of these two areas, E r i d a n i a is a b r i g h t region while Mare Cimmerium is a dark one) a n d last b u t n o t

F i g . 11. - Cliasin p r o b a b l y of t e c t o n i c origin a n d a chain of small c r a t e r s r o u g h l y p a r a l l e l w i t h it. P h o t o w a s m a d e b y M a r i n e r - 9 .

least b y Capen on t h e occasion of t h e opposition of Mars in 1962-63. B e t w e e n 9 a n d 12, J a n u a r y , 1965, Capen observed d a r k stripes, t h e f o r m a n d position of which changed considerably. Similar long and

I'. II ED ERVAKI

n a r r o w d a r k streaks h a d n o t been observed previously. M i y a m o t o (*) lias observed greyish, strange haze over the Amazonis a n d Arcadia Regions, not too far f r o m Nix Olympica, simultaneously with the app e a r a n c e of t h r e e white spots a t t h e Nix Olympica region (5th, May, 1967). K a t t e r f e l d (") has m e n t i o n e d t hat the exact position of the mightily cloud, observed by Saheki on t h e 15th, J a n u a r y , 1950, was as follows: —58° a n d 202° a n d t h e cloud was located a t an a l t i t u d e of 100-200 k m above t h e surface of the p l a n e t . This cloud is not i n d i c a t e d on our m a p of quasi-volcanic p h e n o m e n a of t h e Mars, since t h e K a t t e r f e l d ' s respective s t u d y reached t h e present a u t h o r too late w h e n t h e m a p was completed a n d finished already. Accepting t h a t these grey clouds m a y be of volcanic origin a n d t h e y are clouds of volcanic d u s t a n d ash, Ave can s t a t e t h a t t h e force of some of the M a r t i a n eruption m u s t be very considerable. The outburst, the signs of which were observed by Saheki on the 15th, J a n u a r y , 1950, m u s t h a v e h a d a m a g n i t u d e similar to t h a t of K r a k a t a u (1883) of B e z y m i a n n y (1956) when the cloud reached a height of 80 k m (Krak a t a u ) a n d 36 k m (Bezymianny) respectively. As regards t h e grey stripes, observed a n d m e n t i o n e d b y Capen (3), we can suppose t h a t these m i g h t have been not t h e signs of a simple central e r u p t i o n only, but of a linear eruption p r o b a b l y similar to t h e L a k i fissure e r u p t i o n in 1783 a t Iceland, when gigantic mass of basaltic m a g m a reached t h e surface of the E a r t h .

VOLCANIC FORMS ON MARS

Finally let us summarise the evidences concerning t h e existence of t r u e volcanic landscape-forms on Mars. S p a c e c r a f t Mariner—9 has revealed the existence of four calderalike formations on Mars. Tlicse are as follows [coordinates a f t e r Heuseler ( 13 )]: Nodus Gordii Lacus Ascraeus Nix Olympica P a v o n i s Lacus

+ +

2°, 135° 20°, 117° 25°, 130°

+

10°, 1 1 0 ° .

(*) T h e d a t a c o n c e r n i n g t h e o b s e r v a t i o n s m a d e b y P r o f e s s o r m o t o w e r e g i v e n in H e u s e l e r ' s p a p e r , 1969.

S. M i y a -

E V I D E N C E S O F ACTIVE A N D A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

499

F i g . 12. - M e a n d e r i n g valley on t h e M a r s — s u p p o s e d l y r e m n a n t of an u n d e r g r o u n d lava-flow ( a f t e r Sky a n d Telescope). M a r i n e r - 9 p h o t o .

F i g . 13. - An o t h e r m e a n d e r i n g valley ( a f t e r S k y a n d P h o t o made by Mariner-9.

Telescope).

50(1

I'.

HEDERVÄTU

Fig. 14. - R o u g h l y parallel fissures on t h e Mars ( a f t e r Scientific A m e r i c a n ) . P h o t o m a d e b y Mariner-!).

Note: according to D e Vaucouleurs (8) t h e coordinates are t h e followings: N o d u s Gordii Lacus Ascraeus Nix Olympica P a v o n i s Lacus

—

+ +

5», .18°, 20°, 0°,

130° 100° 138° 114°.

E V I D E N C E S OF ACTIVE A N D A N C I E N T VO LOAN ISM ON M A R S . A R E V I E W

F i g . 15. - 111 o r d e r t o c o m p a r i n g w i t h F i g . 14.: vertical fissures in t h e c e n t r a l g r a b e n of I c e l a n d a t H r a f n a g j a . A c c o r d i n g t o geological i n v e s t i g a t i o n s t h e c e n t r a l g r a b e n is e x t e n d i n g a t t h e r a t e of 3,5 m / k m / 1 0 0 0 y e a r s . T h e vertical fissures ( " g j a " ) parallel t h e b o u n d a r y of t h e m e d i a n g r a b e n of I c e l a n d , a n d lie along t h e a c t i v e e a r t h q u a k e e p i c e n t r e belt of c e n t r a l I c e l a n d ( t e x t a n d p h o t o w e r e m a d e b y Heezen, i n : «Continental Drift», e d i t e d b y S. K . R u n c o r n , N e w Y o r k , 1962).

501

f>02

P.

TIF.DERVAKI

I n addition to these t h e f a m o u s m i g h t h y r i n g m o u n t , discovered b y M a r i n e r - 4 (frame 11) can be regarded also as a caldera of collapse origin. The N o d u s Gordii has a terra-like s t r u c t u r e , similar to t h e H a w a i i a n calderas. I n December, 1971, t h e N A S A released TV pictures of some M a r t i a n craters, discovered b y M a r i n e r - 9 . " T h e s e do n o t look v e r y m u c h like i m p a c t c r a t e r s " — c o m m e n t e d t h e photos Dr. H . Mazursky of t h e U S Geological Survey — " b u t more like complicated terrestrial craters which h a v e experienced successive collapse of their rim walls". In t h e case of Nix Olympica (the d i a m e t e r of which is a b o u t 500 km) t h e M a r i n e r - 9 ' s cameras n o t only f o u n d t h e possible r e m a i n s of a n ancient volcano b u t also revealed a volcanic cone inside t h e g r e a t caldera with a diameter of a b o u t 64 k m . W e can see on t h e enlarged p h o t o of t h e wall of the Nix Olympica caldera t h a t t h e r e is a n a p p a r e n t l y fresh lava-flow w i t h o u t small i m p a c t craters. On one of t h e M a r i n e r - 9 photos there is a long chasm, p r o b a b l y of tectonic origin. Parallel with it a chain of v e r y small craters can be seen. T h e m e m b e r s of this chain evidently are of volcanic origin. On t h e other h a n d , Heuseler r e p o r t e d t h a t relatively small holes on t h e M a r t i a n surface were also discovered a n d these f o r m a t i o n s m a y be t h e place of gas-eruptions. T h e d i a m e t e r of these holes is v a r y i n g b e t w e e n some h u n d r e d metres a n d some t h o u s a n d ones. Similarly to t h e Moon's case, there are riverbed-like f o r m a t i o n s on t h e Mars, too. If t h e y are n o t t h e consequences of t h e r u n n i n g water, one can suppose t h a t t h e y are signs of u n d e r g r o u n d lava-tubes, t h e u p p e r (surfacial) p a r t of which collapsed. Similar f o r m a t i o n s can be f o u n d in Mexico. The m o s t interesting a m o n g t h e volcanic f o r m a t i o n s of t h e Mars u n d o u b t e d l y are t h e long a n d b y a n d large parallel rills. Very similar (volcanic) fissures are k n o w n f r o m Iceland. Therefore t h e p r e s e n t a u t h o r suggests t h a t t h e respective M a r t i a n rills m i g h t h a v e been t h e place of linear eruptions. CONCLUSION.

According to our p r e s e n t knowledge t h e volcanism m i g h t h a v e h a d a n d h a v i n g a v e r y i m p o r t a n t role in t h e development of terrestrialt y p e p l a n e t a r y bodies ( E a r t h , Moon, Mars a n d even Venus as well, since K o s y r e v h a s r e p o r t e d t h a t he f o u n d lines i n t h e s p e c t r u m of Venus, characteristic of volcanic activity). B y other words: volcanism is a cosmical phenomenon.

E V I D E N C E S O F ACTIVE A N D A N C I E N T VO LOAN ISM ON MARS. A R E V I E W

503

REFERENCES I1) BURGESS E . , 1972. - Mars

Since

1lie Dust

Settled.

' N e w S c i e n t i s t " , 53,

784.

(2) CAMERON W . S., 1971. - Comparative Transient Phenomena. Greenbelt. (3) CAPEN C. F., 1968. - Green Haze, P a p e r s , 600-1. (4) CAPEN C. F . , 1971.

Analyses

of Observations

Gray Clouds, and Bright

of Spots.

Lunar JPL

Private communication.

( 5 ) CLASSEN J . . 1971. - The Degassing

of the Moon.

Manuscript.

6

( ) DAVIDOV V. I)., 1970. - See in " B r i g h t Flares on Mars",

" S k y a n d Tele-

scope " , 39, 2. (') DE YAUCOULEURS G., 1971. - P r i v a t e c o m m u n i c a t i o n . (8) DE YAUCOULEURS G., 1971a. - A Mars Chart for the Mariner Flights. " S k y a n d Telescope " , 41, 5. (») DOLLFUS A., 1961. - Visual and Photographic Studies of Planets at the Pic du Midi. " P l a n e t s a n d Satellites " , edited b y G. P . R u i p e r a n d B . M. M i d d l e h u r s t . Chicago. (10) DOLLFUS A., 1965. - Étude de la Planète Mars de 1954 à 1958. " A n n a l e s d ' A s t r o p h y s i q u e " , 28, 4. ( U ) HEUSELER H., 1969. - Betrachtungen zur Vulkanaktivität auf dem Planeten Mars sowie synoptische Studien atmosphärischer Trübungserscheinungen. " Die S t e r n e " , 45, 7-8. (12) HEUSELER H., 1971. - Der Stand der Mars- und Venusforchung. " Ums c h a u " , H e f t 24. ( 13 ) HEUSELER H., 1972. - Der Mars H e f t 4.

ist ein staubiger

Planet.

"Umschau'"

( 14 ) KATTERFELD G. N., 1965. - Volcanic Activity on Mars. N A S A T T F - 4 1 0 ( T r a n s l a t i o n of " V u l k a n i c l i e s k a y a a k t i v n o s t ' n a M a r s e " , P r i r o d a , No. 8). ( 15 ) SAIIEKI T., 1962. - Some Important Martian Strolling A s t r o n o m e r " , 16, 11-12. ( 16 ) SATO T., 1971. - P r i v a t e c o m m u n i c a t i o n .

Phenomena

in 1958. " T h e