1980LPSC...11.2243S A Abstract-Comparison flow extent craters continuous tend the number can craters The diameter. this the Craters addressed of inner not rather resulting small of facies Viking mosphere, placement. 1 ejecta Lunar post-ballistic comparison crater to reduce the more to effects field ejecta process. ejecta than of be be but reveals © densities that images the emplacement in and sufficient circular and The circular Lunar Arandas on the ejecta forming high lobes. will ejecta when Planetary presumably of target On ejecta the outer inner ballistic significant be ejection Secondary of the and facies in reveal Arandas the flow (24 secondaries. to ejecta Moon, secondaries decelerated contrast lobe ejecta considering size. Planetary account ballistic properties). of km for range Institute, Moon of lobes of extends secondary angles differences similar-size highly certain An in Peter secondaries lobe Proc. emplacement, secondary with reflect Mars, and diameter) Rice nearly unnamed for craters and comparable This by Lunar also Institute also history. Houston, 4 alter secondaries martian the Printed University, variable H. crater aerodynamic ejecta crater matches that proposal Planet. approximates Mercury, INTRODUCTION Two may different and mercurian paucity the exhibits suggest Schultz in 34 also and radii are the over-all populations craters • produce Sci. On Texas Mercury km-diameter morphology: to fundamental Provided the United interpreted populations around and of is craters from Conj. 2243 Houston, mercurian surround higher very Mars, consistent and Mars maximum drag Arandas cratering distinct 1 77058 where secondary States most I I greater the and the lunar few the th ejection and around selected by (1980), display continuous rim. of ejecta Texas Chrysie the as crater Jill and secondaries discussions the America secondaries. craters incorporated with extent fractions on martian secondary the 2 Arandas outer p. (Carr, and ballistic Department environments crater lunar NASA Singer angles. 2243-2259. 77001 effects the in flows the crater contrasting (adjusted (2 distinct ejecta Chryse ejecta craters. observed distribution, crater of Astrophysics secondaries et larger impact Although martian, 2 of The and Moon, history fine-size in reveal al., have craters lobes of substrate facies near-rim Planitia radii lunar/mercurian for Similarly, unusual Geological than problems multi-phased 1977; gravity). (i.e., have lunar concentrated craters, from high styles such of the ejecta. and 2% larger clearly exhibits Data lunar/mercurian on Mercury, ejecta target ejection overridden Schultz of and the effects importance gravity, the ejecta the Sciences, than the In Sufficiently of System rim) mercurian must maximum sequence but deposits, cratering contrast, lithology record primary craters. relative ejecta 0.5 appear angles of em- and the the at- km the on be 1980LPSC...11.2243S

2244

©

longitude Fig. martian of region

11, diameter

+46.4°,

Lunar

an

Wx;

P.H.

1.

unnamed

near

Comparison

crater longitude

labeled

and

situated 345.1°W.

Schultz

latitude

Planetary

Arandas

here

crater

359.7°W.

600

Viking

of

+

and

Crater

26.5°,

ejecta

km

(MC-5,

situated

Institute

J.

Mosaic

northeast

Viking

longitude

Singer

I)

facies

approximately

Zm;

on

Mosaic 211-5031.

•

of

the

Provided labeled

of

38.8°W.

selected

northern

Arandas (a)

(b)

211-5031.

Ejecta

here

Viking

34

martian

by

km

fractured

in

the

Crater

facies

in the

Mosaic

NASA

craters.

diameter

fractured

II)

of

plains

211-5382.

an

Astrophysics

approximately

(a)

unnamed in

near

The

plains

the

(c) latitude

24

Chryse

near

km-diameter Ejecta

crater

Data

45

Planitia

+42.8°, latitude

km

facies

(MC-

System

in 1980LPSC...11.2243S butions ondary erties, craters craters Gault, distribution istence/absence gles. traction. travel (atmospheric atmospheric These gravity will range. butions order Second, dicate morphologic Differences © similarly Finally, to Lunar a distributions Material high and in 1979; can and crater to of further shorter we Material different inferred secondaries atmospheric be of and ejection or compare environment. evidence Mouginis-Mark, effects) travel sufficiently diameter attributed secondary in low establish Planetary ejected distance of ejected secondary-crater geologic secondaries martian ejection are shorter angles the must for around at (Allen, complemented Institute interactions. the to than at crater small size/range separation a Consequently, terrains lithology differences be high in ballistic given gravitational angles. on order 1979a). considered. selected (Mouginis-Mark, ejecta 1979). sizes or • the Provided velocity low in size/range to ranges distributions Third, and of A order and Moon All can Previous The (c) angles in evaluate by comparison lunar, the ballistic effects gravitational three we shapes by be measures on Finally, to present variables. than we owing the first aerodynamically due establish mercurian, Mercury distributions variables studies NASA make whether discussed material 1979b) and history. of to compare of to we study unusual secondaries of secondary the Astrophysics the first-order potential, possible consider circularity have and or or relation can ejected larger and is by on the not Mars lithologic concerned around focused Gault the affect martian decelerated craters size/range lithologic the gravitational complementary around lithologic Data corrections at of maximum obviously that et last these nominal the unmodified System on properties al. craters could with variable ballistic martian the effects. (1975). distri- distri- prop- in 2245 sec- will ex- an- the for in- at- an in 1980LPSC...11.2243S

and

lunar

Gault, Primary crater flow

extensive

populations. inferred

2246

selected,

mediate (24 this

analogous lobed

permits

coverage

dominated deposits. as radii

fractured

aeolian

crater

sector Contiguous

to

high

set.

ejecta II). locities

in

radii, theless, of

profile,

types

sector primary

Fig.

distinguishing

resolutions,

resolutions

Three

A

The

An

Selection

Secondary

gravity,

Arandas

a

Crater

km

This

size

completeness

Copernicus

expressed

3)

crater

from

34-km

resolutions.

©

craters.

ejecta

a

of

additional

radii,

size.

from

1979;

out

craters

limits

in

permit

and

Lunar

from

primary

resolving

size

craters

subdued

target

these

range

martian

(>12

additional

secondary

owing

plains

The

of

diameter)

secondary

the I

to

to

the

by

ray.

also

outwash

Ejecta

Viking

diameter

of

might

a

deposit

in Mouginis-Mark,

range

and

P.H.

Ejecta

Crater

only

useful

smaller

terrestrial

10

craters

Ejecta

50

primary-crater

crater

Aristarchus

data

measurements R) lithologies

impact

characteristics could

an

eodr craters secondary

and

this

as

were

to

region

By

crater

prevented

crater

is

within

but craters

km

morphology,

secondary

In

secondaries

and appropriate

(5

rampart-bordered

be resolutions

of

significantly

facies

crater

coverage

facies

provide

Planetary

data

paper.

Schultz

lunar occurs craters,

I

(Fig.

km

order

selected

materials be

crater is

martian

diameter

facies

were

larger

coverage.

attributed

crater

velocity

permits

can

radii,

600

significantly

designated

a

patterned

-50

applied

out

smaller

and

30°

was

1).

of

analogy,

of

(39

be

identified

km

confident

to

The

in

populations

of km)

a

crater

but

craters

to

craters

in

The

craters and

and

of

1979b),

sector

center

craters

nearly on

completeness

the

assess

useful

mercurian

confused

selected,

that

of

resolving larger

km;

Institute

of

martian

(Greeley,

martian

northeast

and

5

larger

Crater

Chryse

easily

Chryse

was

represent consistent represent

to

As

the

crater

than

within

ejecta

fractured secondaries

J.

northern

in

ground

as

were

other

Fig.

(Fig.

its

the

larger

as

beyond

basis

larger

and previous

180°

smaller

selected

and the

comparison.

Singer

on

comparable

identification

the

than

the

Crater

than

to

50

slightly

small

II

crater.

craters

since

radii

herringbone

at

2b)

with

Planitia

a with

the

plains

complexity

0.2

insufficient

in

•

crater

of

et

secondary

the

in

characteristics le)

multi-lobed

outer

km

allows

of

30°

(Carr

than

a

1-2%

than

DATASET

Provided

fractured

plains

two

the Arandas

al.,

azimuth,

and

of

basis

given

crater

12

km

as

within

than

Wx

Moon,

approximately

the

because

secondaries

multiple

in

sector

studies

become

coverage

Ejecta

larger

are

crater

between

the

was 0.2 selected

50

deposits

30°

1977;

Copernicus

and

diameter diameter

displays

resolving

of large

in

in

are

of

Mariner

about

relative of

km

size,

km

interpreted

selected

sectors

a

the

of

size

MC-11

hampered

crater

for

equivalent

occurrence

pattern.

beyond

(Crater

plains

Schaber,

but by

criteria.

secondaries

size

90°

deposits

interpreted

of

Theilig

velocities

radii.

have

number

typically

and

ejecta

in

less

primary

inferred

clear

at

the

martian

the

5

included

to

1

with

sector

topography

diameter

from

markedly

rather

were

secondaries

0.2

km

range

sufficient

km-3

populations

overlapping

IO

Arandas. beyond

and

(see

diversity

shown

pronounced

craters

(96

NASA

45

Zm

facies

12

and

These

identification

Because

images

km-diameter secondaries

of

and

with

multi-lobed

by

1977).

as

other

size

are

crater

is

km

and

around km;

selected

target

crater

as

Batson

in

craters,

approximates

than

secondaries

as

km

for

Greeley,

elongate

incomplete

surrounded

basalt

in

50 on

(Carr,

MC-5 chains

highly

on

10

Astrophysics

highly

regions

in

craters

7

different

resolutions.

characteristics

Fig.

in

and

a

two

in

Viking

craters.

of

crater

Mars

differences

km

radii.

lithology,

crater

diameter

within

Mars

given

of

diameter

to

emplacement

ejecta

Aristarchus

diameter

et

the

at

on

surfaces

but

2a)

another

the but

180°

exhibit

complex

relative

or

et

variable

ejecta

or

of

al.,

1979).

on

of increases large

radii crater

the

was

radii.

primary comprise

coverage

around

owing

clusters

coverage

al.,

wide

denoted

ejecta

secondaries.

irregular

Consequently,

a

by

flow

high

sectors

Mercury

the

1979),

available

120°

basis

was

were

The

an

considered.

within

distances

major

Contiguous

typically

Data

clear

flows

in

1977;

partly

ranges

impact

range

Alencar water-ice

lobes.

and

secondary

eliminate

to

approximate

extensive

Crater

facies target

style.

sector

with

crater

selected

at

or

but

out here

of

recorded.

the the

of

at

plan,

System

evidence

composed

within

crater

large

could

in

Schultz

a

as

mantled

contrasting

in

resolution,

this

sufficiently

of

velocity

The

is

to

increasing

30°

lunar

difference

Although

the

lithology.

as resemble

(Fig.

I

members

from

(I

Arandas

available

out

denoted

6

7

content

relative

shallow

limiting

ranges.

Never-

Viking

certain

sector.

IO

Crater

region not

crater

in

in multi-

crater

a

crater

inter-

inner

data

to

180°

and

The

km;

one

for

the

ve-

lb)

the

by

be

of

of

8 1980LPSC...11.2243S ~: ). crater terrain. be the where a The limits the center ,1:,i-4,•t, (Chryse (1975) chus, increases lobes I R), '• l:;.1, check extends Figures obtained primary. and mercurian distribution ernicus crater Fig. 150-H3. © of of respectively. fields, as the in Lunar Consequently, the for 2. Planitia, the contrast Crater well with Aristarchus 4 to Comparison most (96 any and for maximum Comparison continuous about and insufficient km) s Fig. as crater decreasing all 5 gross consistent of I Planetary (aJ Fig. permit to near craters on secondary 3 (39 The 2.3 of R Alencar asymmetries latitude 5) 4, extent Mars ejecta km) the (2.8 Rand ejecta comparison approximates indicate of minimum resolution, Institute owing crater near data collected different facies {}:::!(·.,:·~ 'j Rand :·•:,~J is +9.7°, t of 4"ii1'1: craters ',,' (Fig. 3 latitude deposits. f'.r-~ , not ·,,·':'~.~-"; both could to R of size. I~ that • ,' :\;i~ ~,1 , t RESULTS ,'1\lj 19.9°W. .. in for 3.1 " incomplete ¼, selected Provided extent ,--\ significantly . . A 4) of azimuth data the and through the + the be comparison the Consequently, the R, 23. the extends The inner Lunar 7°, obtained secondary contrasting extent were respectively). lunar lunar limit raw of by longitude sectors a continuous h ejecta the the lobe Orbiter coverage, craters. data complete of analyzed to craters different of NASA of the to about and and the secondary 47.4°W. crater of IV-121-H2. (a) the the resolutions mercurian Astrophysics the Copernicus continuous the include The Data 360° overlapping ejecta flow farthest within 1.8 extent from (b) populations. Lunar same outer lunar R azimuth craters from lobe (b) the the facies from Orbiter 30° crater crater of ejecta lobe dependent The distance Data approximate ejecta and the Gault of limit arc secondary the lunar Cop- could (CEF) of System provides Crater IV- facies multiple Aristar- sectors Crater of crater facies 2247 et from not the on al. of (2 I 1980LPSC...11.2243S 2248 thick, fiable facies a continuous Gault, delineated, within number Crater even devoid generally is tation martian produced crater relative Arandas mercurian Secondary Figure confirmed © beyond Fig. FDS Lunar for inner if normalizes size these II of 1979; Crater areas of lighting secondaries 3. appear 5 and secondaries. Alencar, by 166727. P.H. The as and secondaries ejecta allows and ejecta crater in deposits different Mouginis-Mark, craters the Arandas (annuli) is I mercurian other Planetary permits Schultz (Chryse characteristic to conditions outer the facies of lobes comparison be Copernicus, become comparable azimuth larger are size overridden at secondary Secondaries limit extend and crater Institute around direct of Planitia). for different also primary J. Arandas than of are Alencar prominent a Singer sectors. 1979a). probable to of the comparison crater of and • these not 2% size. about larger or crater Provided Crater ranges ejecta secondary craters. occur (110 surrounded Aristarchus. approximate favorable. of In on The lunar/mercurian the 5 km) beyond multi-lobed secondaries, population contrast, flow within II R. from Mercury. by inner Figure near primary of and the crater lobes. the the latitude the NASA Figure Arandas, by the lobes Although the 5 the number the crater limit martian ejecta Similarly, shows diameter within This frequency they continuous Astrophysics -63.3°, outer of relatively 4b craters of Crater however, center. paucity lobes are that shows the of subdued each craters ejecta longitude are not secondary the continuous the within are of II thin Data ejecta annulus relatively This of always that Crater extent are lobes relative are (Schultz matched 104.0°W. depressions secondaries ejecta System not represen- the generally the facies of craters II, identi- of to ejecta easily same lobe. large areal rare, both and but the the by of 1980LPSC...11.2243S ! ii' - !!:..06- e.02- ...... ::E l,U 0.04c- 0 Q < GIi: GIi: GIi: GIi: GIi: >- >- v U ::E : l,U 0 1,U z ,c( < ,c( GIi: u a absence density it largely 4a. than terrestrial It around .04 .00 .02 .04 .06- .00--..._1_._..._1_.__1_.__1_.__1_.__1~ .08 .021------J:..~~.,.______,,f--=-. . . .08- .06,- 08- 00.___.__1_..._1_.___..__ to .1 .1..-----,,,------, .1 should 0 There .------.1------, 1-----l----il~_.;...,.le....u.._....,__,__,_l_-;...l.,,.,.,_~I--'--' ,- - - - for outer Fig. Alencar tinuous and confusion © (RANGE)/(CRATER Lunar due Aristarchus of Aristarchus. of 4. Arandas are (OL) secondary view be Comparison ... u ... secondaries ejecta .:·?:::i.:- to (Mercury), . . . . .: 2 .. and remembered, significantly ·. .._ _:;\{Ji;}\(;· flow the ..,.. used. , with (see ...... u 3 Planetary .. facies I .. :•'.:.·::. · lobes larger _:::, ., is Fig. ~._,___-'-'--~--'~ ·.·,, •.· craters of 4 Eratosthenian Copernicus I I Shoemaker Although ~:./ significantly is secondary are between indicated 2). RADIUS) .... ARISTARCHUS extent Institute COPERNICUS ._::. 5 ··_:\~~ fewer secondaries ·: indicated. The , ALENCAR however, ·: for . .: '. .. >\ 6 :'.:':::./,_.. 1 minimum .. (Moon), lighting crater Copernicus by of ... the (1962) , • CEF. less 7 its Provided secondaries rim size A and that continuous than and (b) limitations noted comparison distributions and Aristarchus The maximum the e.02 - by , - .... l,U l,U 0.04 ~.06 0 1,U < GIi: >- GIi: GIi: z V V .... 0 Gll:.00.___..__..___,__,1.1..__,1.__,1.__,L__ < GIi: GIi: ::E >- V A. GIi: ti ~.04 l,U and Aristarchus the b between 2 · .08 .08 .06 .06 .oo---'--'--'~-'- .08 .02- .04- martian the 02 a .1 .1 .1 R absolute number similar ,-----,----,----,-----,------, !------~-~---; r------,------,------, r-----t---"1--'+...:.:.._,;..,.,.,.~~~~~ r----.----r--r------, - - and NASA from ejecta (RANGE)/(CRA are within of extents (Moon). craters, 3 lighting secondary not R Astrophysics the ::! deficiency around i a C facies, number 2 and 30° of The a rim Crater ...... -o ) the are problem sector. e e a a )C ·-: 4 3 conditions ... 0 - limit )C .'..:/ii~~i~-<- e e a R ,c inner of Copernicus. craters nearly as ... O ... I, -~ TER for ·- e of C 4 Aristarchus and of (a) Data Crater noted (IL) the secondaries .. ·?{:· Copernicus Craters with 0 ... RADIUS) a e )C ...... attributed 5 the 1_...__1~ System ... 0 con- ARAND and l)C II, for in Lunar :· same. 6 <-;:, 2249 . Fig. The AS the II is .. 7 1980LPSC...11.2243S 2250 s ... < < u .... 11:11: 11:11: >- !!!...... condaries 11:11: 11:11: Ii. 11:11: 11:11: < < u resolution retical w as clearly consistent 11:11: thereby >- u Crater Orbiter deficiency. daries, larity: 0 0 z C w pernicus, < 11:11: .... w 11:11: j:: 1977). C w a Figure Short 0.02 0.06 0.04 0.08 0.02 0.04 0.02 0.04 0.06 0.08 many 0.08 0.06 0.10 0.10 0.10 © few different Fig. olution 0.0 Lunar values resolution I as identifying "' ::, u <[ "' ... u f u 0 z ffi <( ... ::, ::c "' iii: <[ <[ V .. "' photography permitting and and secondaries 5. as 5b 1.0 RANGE/CRATER Aristarchus, P.H. shown within is identification The 20 The cut-off and 90% confirms the 15 craters dependent 15 2.0 long of 10 size-frequency Planetary Schultz 5 short/long 5 lunar crater 3.0 is of of in R 5 10 0 10 10 axes counted within secondaries normally NUMBER a the Fig. 4.0 the 10 measure the of and for collected Arandas and and RADIUS 5.0 on of craters Institute 30° of this 4b. 5 5 similarity above the mercurian 5 axes J. each distribution terrain Copernican Crater sectors. 6.0 5 quoted region, Singer mercurian data. 5 of 5 the 7.0 in typically 2.2 (not • secondary circularity. resolution Provided the The and I The in pixels as have craters, of included secondaries the horizontal more 2.2 crater is secondaries secondaries. .::: .... 1¥ 1¥ 0 C 1,1,1 1,1,1 c( near crater significantly b secondary secondaries pixels by cut-off. in - ::::::: 2 .... 1¥ u .... u e 1¥ 1¥ 1¥ 1¥ c( c( c( 1,1,1 1,1,1 1¥ 0 C u c( 1,1,1 z crater Arandas rugged whereas the Figure diameter 0. 0.04 0.02 0.02 0.08 0.04 0.06 0.06 0.08 0.10 in 0.10 lines 78, Alencar NASA (Saunders within 0.0 Fig. from were 0.8, is indicate "' - ...... < "' ... < u z C ::> z terrains. z "' "' ...... = < < u ::> z C 6 crater The not 1.0 Crater poorer. 5b) Astrophysics with the reveals RANGE/CRATER are 0. Eratosthenes illustrated measured reflects 15 7, 2.0 same reduced has the 10 unidentified et distributions wide and II s 3.0 Although approximate al., In even relative NUMBER that displays 10 0 10 10 0.6, rugged the ranges owing Data 4.0 1975), number 10 and Alencar, fewer respectively. areas difficulty 5.0 complicate System RADIUS to s the a (Schultz, s s s s rectified, practical res- in between terrains, the 6.0 notable of secon- s circu- of theo- Co- s 7.0 se- in 1980LPSC...11.2243S '§" X (0.9) 7 and dispersed). C) In Five <( with not be potential, similar. 0 included Z more X V, <( pulled the !:: :x: >- 0 :3 secondaries, Ill:: ::::, u a reveals 0.0 o.o~~~~_._~~-..___,__~~_._~ 1.0 0.0 1.0 contrast, 1.0 adjusted .9 .2 .4 .6 .8 .5 .7 .4 .6 .9 .9 .3 .2 .8 .7 .4 .6 .3 .8 .3 .7 .5 .5 .2 .1 overall .1 appreciably Mercury. ,--.,----,-----,----,--,---,-,----,----.----.-----r-. .___.____.__--'----'---'----''---..__-'---'--'---'-----' 1 3 5 6 5 4 3 2 1 0 ,--.,---,-----,----,---,---,,---,----,----,---,----,---, .----r----,-----.---.-----,---,-,----,----,----,----,---, ~-'--~~--'-~~-..___,__-'--'---'-----' Crater within parameters different Fig. the statistical elongate © closer The .,., Lunar in data. 6. (RANGE)/(CRATER that ejection I I distribution. the The Gault, 8 II simply the distribution craters. to as I I R The spread and such Figure are or data), mean the and observed I I different identified affect large irregular Planetary also I angle, et rim a The for of show circularity I however, correction 5 the al. deviation 7 more and indicates error the Crater I the RADIUS) data. of 9 8 (1975) by beyond lower ejection I Institute than secondaries ARISTARCHUS gravity increase COPERNICUS secondaries bars size circular Gault ALENCAR of 10 for I have :i: all represent secondaries circularity most exhibits showed DISCUSSION that distribution 11 Arandas - the measured • velocity, of 12 et this Provided more (0.8) Crater A notably Mars region al. of a comparison around population a that near one (1975). than elongate distribution Arandas secondary beyond and - V, ...... _ X ..., e 0 C) z <( V, .... <( 0 >< a,:: :x: !:: ..., associated >- <( a,:: u u ::::, a,:: ejecta by I standard-deviation b 4 of of the affects in R 1.0 those 1.0 the :! .4 .6 .9 .5 .8 .7 .9 .9 .4 .7 .6 .4 .8 .7 .5 .1 .2 .3 Copernicus .1 continuous compared secondary ,--.---,-----.----r---r---r-r--r---.--r--.----, .__.,____.___,__--'---'----'-.__-'----'----'---'-----' Chryse indicates Secondaries secondary NASA plans. 8 of size, craters without generally around R. the (RANGE)/(CRATER secondary 3 5 6 5 4 3 2 very I :i: with Smaller Astrophysics the Planitia and near-rim I Secondaries at with craters: similar drastically I different paucity I statistical I ejecta and Crater Arandas. crater ejecta are at I I craters Crater secondaries Aristarchus large I I on highly distribution rather 7 to for ranges population Data I, I - gravitational spread Mars state RADIUS) 8 the but associated I I ranges the modifying I. 9 than ARANDAS System :i: I circular gravity- :i: for clearly of Figure is 10 (solid, Moon I 225 (not also 11 can are of is 12 I 1980LPSC...11.2243S 2252 - ! .... c( 1,1,1 >- ...... c( V Q. adjusted .... c( 1,1,1 u >- in eters daries 0 c( Q the which z V 0 1,1,1 c( .... j:: 1,1,1 1,1,1 Q Gault low-viscosity 0.08 0.04 horizontal 0.06 0.08 0.04 0.02 0.08 0J0.------Nc-U--M-:B~ER-----, 0.06 © 0J0.------NU,,..M_B,..,,E.,..R------, duced 2 Fig. relative ejecta Copernicus Planitia completely even Fig. 4b). to nounced developed other Lunar 0.0 around R incorporated increasing and of 7. distributions 8. ! :; ...... ,c( C => z z less P.H. flows. to the 1.0 The RANGE/CRATER Comparison than areas and on 20 2_0 change Greeley match likely rim Crater around than 15 2.0 size-frequency for Mars and 10 Planetary Schultz the for gravity. targets would the 5 to conditions 3.0 Aristarchus occurs martian impacts assumed shows account 10 10 or certain few II (1978) of for 4.0 be and]. buried 10 10 and eject the Institute represented craters near a RADIUS Crater the 5.0 distribution martian for ejection of size-frequency similar in Arandas, and 5 5 5 5 after the martian Singer material the lunar 6.0 high-viscosity the beyond I • Greeley relative rim before the craters. size-frequency 7.0 angle Provided by near-rim craters, and gravity. observed of the the therefore, at (top) secondaries from absence distribution may continuous Increased multiple appreciably et by and The 45° contribute al. range except secondaries. targets. c( the u >- ct c( >- Q O u 1,1,1 ct j:: ffi .... 1,1,1 0 of after distribution to large (1980) 0.04 0.021----4~"v-~=-J:c:;;:;;ii==,,,,.J 0.02 0.06 0.08 0.06 0.04 0.08 ejecta NASA 0.06 0.02 secondaries 0.04 0.08 within 0.10.------, suggests 0.10 ejection 75°. of ejecta of (middle) 0.0 number secondaries within 1----=~"=T-~-,._~,._,,...µ,..;:i,.-i secondaries As Thomsen to higher lobes ..,, .,.u "'"' ... -1~ uu ...... "' ..,u =2 "'"' -S ,-I<>< ...... -c"' ...... uO ..,u uO the Astrophysics demonstrated facies. :, ...... o u z the u 1.0 C in angles beyond 20 same RANGE/CRATER reduction the The Fig. of around of massive 15 the 2.0 0 10 10 0 0 10 10 10 secondaries ejection Crater Crater influence (Fig. may relative 7, 5 within 3.0 ejecta the paucity et NUMBER the Arandas 10 of Data al. ejecta not I 4a) multi-lobed II 4.0 most in range 10 10 the areas that (1979; angles account and was Chryse flow System within 5.0 of flows of same (Fig. pro- RADIUS 5 5 5 5 5 5 5 5 due 5 5 5 5 for are re- impacts param- secon- 6.0 lobes, 1980) from 7 .0 1980LPSC...11.2243S of raised (1974) few effect ejection crater confirmed in Ejecta to to ballistic and ejection condaries angle angle increased High tention this water however, Arandas. ejecta Copernicus, velocity. result shown system size Greeley ejection ducing daries great al., minution. velocity proximity, et The If Ejecta The error. be (sin secondaries al., the region © 1980). is secondaries the addressed depths of (or of flow Lunar or above that in deposit notes 0) of greater below about few the in 1976; may assumption that 75° velocity, range. angle observed angle is 113 More size 75° et ice, Such very a that sufficient Therefore, Fig. velocity) associated Moreover, • this rather field. high ballistic should of Highly rather low-density secondaries al., Consequently, and form and ejection the and that would and 10 Gault shock a Mars and the of circularity (Schultz detailed low) 8. a with for critical Planetary enough, (Greeley cm. Different 1980) resolution will thereby associated than Alencar. physical range 45° This crater detached velocity than secondaries 21% increase dispersed different range would that size exhibited reduce ejection and vaporization If distance scour (producing high with angles the a gain size 45° due reduction the theoretical and reduction single the cloud Institute to around craters size Greeley, influencing and et for ejection dynamic state also flow ejection would Consequently, the Crater cut-off. an pre-impact to be fluidized can further the the vector al., Gault, with were angles material ejecta, secondaries increases a the incorporating from increased ejecta surface around included be of fields also low be observed range with 1980; • Arandas the increase of is increased expected atomized Provided Arandas applied angles II and 1978; higher decelerated velocities For angles forces support. the can 1979). insufficient yield will this ejecta the block. maximum however, in mounded and Thomsen of A without by Crater target experimental example, two as affect primary in impact spatial comparison component Boyce, reduce low theoretically strength a population even than of illustrated the suggestions alone should by to the For this deposits If velocity to and this factor contrasting liquid Arandas However, of the lithology Crater massive I size viscosity the producing increase impact by will floors distribution study those were Arandas-size angle ejecta less ballistic to et fraction NASA the perhaps Crater and 1979; at formation disperse aerodynamic 66%: at al., produce of and 6 R 6 of not (Greeley required ballistic effective studies may I the produced in the of (and, may for two require secondary are Astrophysics affect (Fig. enough, that angle contains 1980; produces Schultz from secondary and media 37% solids the penetrate Fig. II. range), secondaries in large time cannot size lead Crater the for be any the at of a the of 6) few It are both calculated Austin due Arandas increases range to late-stage, 4b, craters same formed et further the secondaries. for of are secondary secondary of the to supports traveling such should target by and achieve liquid large deficiency drag, craters clearly then al., Arandas to formation account the increased the I, the therefore, Data same secondaries only crater the ejecta same is the for an et Gault, Aristarchus, 1980). distribution as distribution this amounts an thereby (Schultz most secondary. discussion. an material System ejecta surface al., be according impacting beginning increased the range, required. a the they near-rim the in ejection ejection ejection size, craters. craters. with for critical similar noted, secon- 1980), of Gault likely If (Carr same close same com- 1979; con- may 2253 and are the the se- re- an an an of of to et in 1980LPSC...11.2243S 2254 in trates have possibility secondary small-size extend dynamic daries with where sive base decelerated martian 1980). The late-arriving © overturned surge. a onto that ejecta Fig. three Lunar a grooves that second scouring through craters. 20 9. exhibits effects the P.H. overriding ejecta results Martian craters; causes: km-diameter do A and ejecta. outer similar possible ejecta and not Planetary radial Schultz the on flap action Occurrence ejecta (but crater from the ridges fit small-size Faint and/ outer little of grooves that sequence inner within lobe. above and (MC-7, by smaller cause high or Institute crater mass ray continuously override lobe. late-arriving J. lobe. This ejecta (arrow) ejection Singer Nd; the systems of ejecta. the of arriving sequence craters has This Viking in ray • missing 20 selection and critical configurations Provided early-arriving Elysium km been systems morphology The ridges angles, Frame extend diameter) (Schultz cross of ejecta beyond proposed secondaries emplacement combination particle by extending 86AI4. criteria Planitia the the lower indicates from materials, near the and NASA ejecta, inner producing is size) latitude for across Arandas used relative not ejecta region Gault, suggests involves Astrophysics lobe Arandas of that which unique not inner, perhaps in +35°, these flow of of 1979). a this velocities, high-velocity, deposits (Fig. forming late-stage ejecta thick longitude Mars comprise small-size factors (Mouginis-Mark, and lobes; study. Data analogous 10a) ejecta Figure is deposits ( + and identifiable flow System 211°w consistent can and and dispersed 35°, The lobe the but of 9 secon- small- result other aero- illus- 211°) mas- to first and un- a 1980LPSC...11.2243S © Lunar ejecta Fig. resenting barely secondary ejecta statistics Viking 10. and large flow recognizeable Frame The Planetary but detached craters lobes enough martian may 32A21. from below represent segments to Institute secondary crater be (b) the unaffected the Hummocky continuous Arandas. of low size • ejecta Provided craters. velocity, limit by facies. units deposits. (a) A aerodynamic used (a) Area comparison by Ray viscous probably in Viking the shown system this Such NASA ejecta study. Frame drag, associated units is composed of approximately Astrophysics but or secondary also Such 32A32. recocheted small are with rays of not enough Arandas small were Data craters included 30 pieces km to formed ( System <0.5 and produce across. of in rep- km) the the by 2255 1980LPSC...11.2243S 2256 ies; takable. to beyond size not by form Greeley of rated segments separated central daries illustrated Many tem morphologies Although nevertheless might 1979; The Figure 2. 4. 3. 1. the be impacting associated therefore, ejecta © perhaps The continuous tically size Two secondary morphology Although crater plains curian curian lobe relative from very Secondary included Schultz Lunar be of ejecta. (Schultz third mound. the They et these one. recocheted 11 from on the P.H. similarity by of few extend the craters al., a ejecta in and modified cause craters. craters. are associated systems have Mercury Arandas secondary distance illustrates on number et may in the main they Such secondaries secondaries with and the numerous 1980). Planetary Schultz A craters, significantly craters ejecta al., a this to and lobes with Chryse is central global ejecta implications be Mendenhall, may lobe these in secondaries significant best and and the 1980). study. Alternatively, related of maximum suggests (2 and andJ. the extensive facies with a crater associated Institute but of as CONCLUDING indicate primary radial fluidized flow R) detached scale. illustrated type martian deposits, Planitia mound appear larger other distribution observed Arandas, The In coalesced as Arandas more Sin[;er to lobes between clusters addition, ranges of distribution the that for The groups • 1979) possibility typically extent multi-lobed a than craters flow Provided and has crater to as impact from with high-velocity, circular continuous interpreting (Fig. yet neither they by following in be but well is and without dispersed been 2% at lobes and Crater the of hillocky of the more shown of two the numerous not used impact are may 10b). are by craters has REMARKS as the dispersed secondaries the laboratory chains. of of association atmospheric than recognized uprange the multi-lobed in classed secondaries craters below elongate circular been diameter forming ejecta represent widely major in I Secondary ejecta ejecta in the NASA ejecta the deposits on to this secondaries low have Fig. A secondaries reproduced produce fractured our Mars fluidized statistics ejecta for points extends as more Astrophysics study flow dispersed facies (Gault ejection-angle with (Schultz secondaries than llb. and of major for with a size-selection lower certain craters nor radial around craters and secondary the lobes, tightly lobe. certain a in can the is a of and target Arandas to ejecta plains diffuse limited primary. associated of differences small, the craters velocity and can in similar-size larger to be ejecta martian about in Data lunar Greeley, martian commonly the the clustered Arandas, extent large summarized: the Mendenhall, lunar be effects that region component halo crater, the laboratory System flow inner secondar- of is identified criterion. groups the fractured and fluidized enough craters. did unmis- results similar secon- with of crater in and sepa- 1978; same dras- have mer- mer- flow sys- but not are yet the the is a a 1980LPSC...11.2243S

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2257 1980LPSC...11.2243S 2258 Allen Carr Carr Gault Gault Boyce Batson Austin few ogies. targets 50 and in inferred pre-impact (e.g., enhancing and Chryse Singer result namically with 051-001 appreciate Acknowledgments-The and Institute Lunar 51-54. eds.), impact liquid morphology. investigation 5. 6. The experiments km) Planetary M. M. Heitowit, © large Greeley, C. C. C. overridden account a The Simple of D. D. J. gratefully M. R. Carr Lunar The in with targets: p. lithology wide Planet. H. H., would is craters martian M. Arandas. E. E. Planitia M., from 137-176. G., the a operated and outer (1979) secondaries P.H. (1974) and Crumpler decelerated the the extensive (1979) grain late-stage and Institute Bridges and of computer Reports variations Thomsen models Schaber analogs Sci. and for National be acknowledges impact Greeley outer various 1963) 1978; will Large Planetary Schultz craters ejecta Impact exhibiting Schaber, are TM the A size expected by C emplacement the onf. J. P. Contribution method of contribute the for authors G. cratering X-62359. indicate correcting inner flow consistent J.M., programming lunar A., Schultz M., and secondary flow R. paucity Aeronautics Planetary 11th. around cratering. rampart G. Universities photogeologic lobe in fine-size and can (1978) Cutts and Institute enhanced lobes (1977) secondary secondary for participation 1977). ejecta to overriding appreciate low Ruhl This J. dynamics: Inge be of of relatively have measuring R., Singer craters? and of Exploratory No. Arandas, Geology to ejecta Martian certain In volume. for yield interpreted S. (Schultz with and cratering of J. ejecta REFERENCES secondaries Greeley • lobe. a Here Space A F., 418. L. craters: Gault, John Provided relatively possible more comminution. 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Program. al., Greeley SP-48. the et experiments are Geophys. Contract basaltic arrival ejecta constitutes growth Lunar 82, medium-size do al., using Res. (1980 fractured of appear formed NASA 1980). and Data small H. and The are 4055-4065. 146 not of angles ejecta and We target (1977) 82, 1977). and impact No. C. period. Crater forming Res. Calculational pp. System flow consistent and plains, appear also relatively 4039-4054. TM-80339. in P. owing Aerody- Wood. the to Planetary NSR viscous- Schultz, Martian (Gault (Gault Lett. shown lithol- plains 1980). greatly could lobes Such crater have Lunar Proc. I (5 Jill 09- as to or in to 6, - 1980LPSC...11.2243S Gault Greeley Gault Shoemaker Greeley Mouginis-Mark Saunders Mouginis-Mark Mouginis-Mark Schultz Schultz Schultz Thomsen Thomsen Theilig Schultz phys. impact formed cratering Chryse volume. altitude, Planet. Kopal, complexes Conj. secondary and Tech. laboratory-scale Institute, Lunar 15, investigation Mars. 1148. © 202-219. D. D. Planetary Lunar E. P. Res. P. Lunar P. P. Mem. 10th, R., R. J. and craters E., ed.), in E. Sci. Planitia. R. J. J. and H. H. and H., H. in Geophys. E. Theilig Houston. rock. M., and M., impact Fink S., Guest 84, Planetary (abstract). (1977) p. viscous and and Conf. M. and 33-723. and p. Greeley target Gault of P. P. P. Institute, on 2741-2756. Mutch 7669-7687. E. Austin 283-359. Austin impact Proc. (1980) (1962) J., (1979b) Gault (1979a) Mendenhall J. impact Planetary Planetary E., J. Mercury Endogenic D. processes 10th, material. Geophys. D. Res. Gault E., targets: 27 Guest R. Science Heitowit T. 6th In An M. Interpretation E., D. M. cratering Murray pp. p. cratering Houston. Ejecta Martian (1979) Academic, 84, A., Symposium Lunar E. emplacement G., D. and G., 2651-2668. and Institute, Institute J. (abstract). Laboratory J. 7994-8010. modification M. (1979) and Res. E., XI, E., Ruhl (1963) Plains Mendenhall the Schultz emplacement Geophys. J. H. fluidized dynamics: and event Jones Snyder p. Carr B., 82, Moon. Atmospheric (1979) N S. 753-755. Houston. of and The • on Planetary .Y. Dzurisin 4093-4109. In F., P. lunar M. (abstract). Provided sequence experiments. K. Hypervelocity of Res. channels crater D. H. J. partitioning Lunar On Schultz early H., M. L. A impact of Geophys. B., craters. (1980) Lunar the comparison (1975) 82, H. D., Masursky the morphology: Science and time effects Guest for by formation 8011-8022. (1980) In in craters and P.H. martian and The martian the the Planetary In Lunar Guide Proc. material of Res. Impact, Malin J. on Physics NASA Planetary energy X, Lunae Multiple-body and development H., on E., impact martian of Lunar 80, and p. of to fluidized Mercury. variations M. and Orpha! and motions. secondary basin the Science 1078-1080. Planum-Chryse Astrophysics 2444-2460. p. for and Planetary C. Cutts 419-456. Planet. Institute, crater Schultz use ejecta hypervelocity (1975) Astronomy secondary ejecta D. Phys. of with of impacts: XI, Proc. J. L. Bamburg. emplacement. the Mariner Sci. A. Some craters Science Lunar P. p. craters crater (1979) Houston. Earth Data Lunar H. (1977) ejecta 1006-1008. C Planitia craters of implications onf. comparisons (1980). impact and the Planet. size, System Calculational (abstract). XI, images. Proc. Planet. Geology plume 11th. Moon Planetary by region p. latitude, J. Impact craters Lunar Lunar ejecta 2259 Inter. 1146- Geo- This JPL in Sci. (Z. for In of of of a