THE GEOLOGY
OF THE
TERRESTRIAL PLANETS
NASASP-469
THE GEOLOGY
OF THE
TERRESTRIAL PLANETS
Michael H. Carr, U.S. Geological Survey
R. Stephen Saunders, Jet Propulsion Laboratory
Robert G. Strom, University of Arizona
Don E. Wilhelms , U.S. Geological Survey
Michael H. Carr, Editor
NI/\SI\
Scientific and Technical Information Branch
1984
National Aeronautics and Space Administration
Washington. DC
Library of Congress Cataloging in Publication Data
M ain en try under titl e :
T h e geology of th e terrest r ial pla nets .
(N ASA SP ; 469)
In cludes index .
I. Pl an et s. I. Ca r r , M .H . (M ich ael H .) II. Series.
55 9 .9
83 - 16348
1984
Q B60 1.T47
For sale by the Superintendent of Documents
U.S. Government Printing O ffice, Washington, D.C . 20402
FOREWORD
With the launch of M ariner 2 to Venus in August 1962, for the first time man reached beyond the confines of
Earth to explore the rest of the solar system . The two decades that followed have appropriately been called the Golden
Age of Plan etary Exploration, for a succession of ever more sophisticated spacecraft has been sent throughout the
solar system , visiting every planet as far out as Saturn. One spacecraft, Pion eer 10, has even left the solar system
and is at the start of an endless journey through interstellar space.
The advance in our knowledge of the plan ets as a result of this activity is so enormous that it is difficult now
to look ba ck to the time of that first launch and appreciate how primitive our perception of the plan ets was then.
Even the terrestrial plan ets, those closest to us, were almost unknown. M ercury was known only to have a few smudgy
markings, Venu s appea red as a featureless disk, and our notions about Mars were colored by a false belief in the
presen ce of canals. Now these bodi es are comfortably familiar, and we have a sound basis for hypothesizing how
they mi ght have form ed and evolved to their present state. For the M oon, a plan et-sized bod y (though actually a
satellite), the advan ces are especially striking. In 1962, the Moon was com m only perceived as a primitive undifferen tiated bod y, a sample of the primordial stuff of the solar system . The origin of its numerous craters- whether by
imp acts or volcani sm-was hotly debated, and estimates of the age of the surface ranged from billions of years to
relatively few. There then followed a series of spacecraft missions which culminated in the landing of men on the
lun ar surface during the Apollo pro gram and the return of sampl es to Earth for analysis. We discovered that the
Moon , like Earth, ha s experienced a com plex geologic history which can be precisely outlined by dating returned
sam ples. The origin of most cra ters was un equivocally established as impact, and the surface was found to be an cient.
In several ways, the geologic history of the Moon is now more securel y established than that of Earth.
Concurrent with this vigorou s exploration of the solar system was a revolution in the science of geology. Indeed,
the two decad es following 1962 might also be called the Golden Age of Geology, for it was during this tim e that
the theory of plate tectonics was formulated . Exploration of the sea floor, detailed monitoring of global seismicity,
and discovery of reversals in Earth 's magn etic field all led to the conclusion that Earth's surface is divid ed into large
rigid plat es that move with respect to each other. This perception transformed the discipline of geology by integrating
a multitude of seemingly disconnected geologic observations into a single satisfying theory. Furthermore, we are beginnin g
to realize that impacts, which have been so dominant in sculpting the surfaces of other plan ets, have also had a major
role in the evolution of life on Earth.
Thus, the knowledge gained through space explora tion is leading to the new science of comparative plan etology.
Although each plan et is unique, all have mu ch in com mon. Whil e each can be studied independ ently, a greater understanding is achieved by examining the entire set. This book outlines the geologic history of the terrestrial plan ets
in light of recent exploration and the revolution in geologic thinking. That such a volume could be written at all
is a tribute to the engineering virtuosity that has made plan etary exploration a reality.
Burton I. Edelson
Associate Administrator for Space
Science and Application s
National Aeronautics and
Space Administration
June 1984
111
TABLE OF CONTENTS
Chapter
Page
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
111
2.
ASTEROIDS, COMETS, AND PLANET FORMATION.................. ...........
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Asteroids and Comets
Meteorites
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Formation of the Planets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
5
5
5
6
7
3.
MERCURY
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Orbit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Rotation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Internal Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Magnetic Field
Atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Infrared Thermal Emission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
General Surface Characteristics
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Photometry and Color. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Surface Composition
Craters and Basins
Ejecta Deposits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Interior Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
The Caloris and Other Large Basins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Crater Statistics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Major Surface Units
Smooth Plains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Intercrater Plains and Cratered Terrain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Hilly and Lineated Terrain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Tectonics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Lobate Scarps and Lineaments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Causes of Crustal Deformation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Surface History and Thermal Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Discussion
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
13
13
14
14
15
15
17
17
17
17
20
21
22
25
28
33
36
37
42
45
46
47
50
51
53
55
4.
VENUS
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Early Telescopic Observations
,
Orbital and Rotational Motions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
57
57
57
58
1.
v
1
TABLE OF CONTENTS (continued)
C ha pte r
4.
(cont. )
5.
6.
P age
Earth-Base d R ad ar Observati on s of th e Surface
Sp acecr aft Observati on s . . . . . . . . . . . . . . . . . . . . . . . . .
Cons tra ints on th e Co m pos ition of V enus . . . . . . . . .
V en era L ander R esults . . . . . . . . . . . . . . . . . . . . . . . . .
Eo lia n E ros ion and Tran sport
C he m ical W eatherin g . . . . . . . . . . . . . . . . . . . . . . . . . . .
G lobal T op ography a nd Surface Rou ghness . . . . . . . .
Su rface Rou ghn ess . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bright R ad ar Rin gs . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gravity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Plat e T ectonics on V enus . . . . . . . . . . . . . . . . . . . . . . .
Ackno wledgme n ts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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EA R T H
In tr odu ction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Prop erties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Plat e T ectonics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formul a tion of th e Theor y . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Presen t Vi ew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
P ast M otion s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Interi or of Ea rt h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The C rust
The M antle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T he C o re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fo rmation of Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bulk Co m pos ition of Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formati on of th e Co re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The A rch ean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The P rot ero zoic
Evo lu tio n of th e Atmosphere a nd H yd rosphere
Summary
Acknowl ed gm en ts
MOO N
Introducti on
Scop e a nd O rgani zati on
Two D ecad es of Lun ar Investi gat ion s
C ra te rs
G en er al Features a nd Origin
Crate ring P rocesses
Di stribution and Stra tigraphy
Ba sin s
Introducti on
Orientale
Ba sin -F ormin g Processes
Di stribu tion and Strati gr aphy
T erra Breccias
C rus tal Structure
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84
89
91
92
93
95
95
96
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102
103
105
105
107
107
107
107
115
115
118
122
126
126
128
131
138
143
143
VI
TABLE OF CONTENTS (continued)
Page
Chapter
6.
(cont.)
7.
Composition and Mineralogy
Texture and Structure
Fra Mauro Formation (Apollo 14)
Imbrium Massifs and Apennine Bench (Apollo 15)
Cayley and Descartes Formations (Apollo 16)
Serenitatis Massifs (Apollo 17)
Summary of Emplacement Times
Maria
Introduction
General Features
Stratigraphy and Distribution
Mare Basalts
Introduction
Composition, Mineralogy, Texture
Emplacement Ages and Petrologic Relations
Petrogenesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Emplacement History
Tectonism
Style and Extent
Mare Ridges and Arcuate Rilles
Crater Floor Fractures
Straight Rilles and Scarps
Deformational History
Geologic History
Geologic Style of the Moon
Pre-Nectarian Time
N ectarian Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Early Imbrian Epoch
Late Imbrian Epoch
Eratosthenian Period
Copernican Period
Terrestrial Perspective
Acknowledgments
MARS
Introduction
Mars Within the Solar System
Telescopic Observations
Spacecraft Exploration
General Properties of the Surface
Physiography and Topography
Surface Temperatures and Thermal Inertia
Albedo and Color
The View From the Viking Landers
Surface Chemistry
The Atmosphere and Surface Volatiles
The Atmosphere
Volatiles in the Surface
VII
146
148
150
153
156
159
161
163
163
163
175
177
177
178
180
185
186
187
187
187
189
189
190
192
192
192
194
195
195
195
196
196
197
207
207
207
208
209
210
210
212
214
214
216
217
217
219
TA BLE OF CONTENTS (contin ued)
C ha p te r
7.
(C OIl!. )
8.
P age
C ra te rs a nd C ra te r A ges
D e nsely C ra te red T errain
Cra te re d Plat eau
l nt c rcrat er Plai ns
Fo rm a tion of the D e nsel y C ra te red T errai n
S pa rsely C ra te re d Pla ins
Low-La t itu de P lai ns
H igh -La titu d e Plai ns
Frett ed T e rrai n
V olc an oes
T he La rge Sh ield V olc a noes
O lymp us M o ris A u reole
Sm all Sh ield- like V o lcan oes
A lb a Pa te ra
An cient V olc a noes in the Sout he rn H em isp he re
Small V olca n ic Feat ures
V olca ni c Hi sto ry
T he T harsis Bul ge
G ra vity
Ca n yo ns
La ye red Ca nyo n D e posits
Formati on of th e Ca ny o ns
C ha n ne ls a nd V alleys
\·Vind
T he Poles
C onclus ions
A cknowled g m e n ts
220
222
222
224
225
22 5
226
229
232
234
234
238
239
240
241
24 1
24 3
243
244
24 7
250
250
25 1
256
259
262
263
SUl'vl MA R Y
I m pact C ra te r ing
V olc ani sm
T ect oni cs
In te raction Wi th the At mosphe re a nd H yd ro sp here
Pla neta ry Ev olut ion
265
265
266
26 7
26 7
268
A p pe nd ix. M aps o f the Te r restrial Plan e ts
'. '
27 1
R efe re nces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1
I n d ex
315
vm