Fina l Report NASA Grant

MAG 5-333

July 1, 1983-Hay 5, 1985

"Wilso n Study Cycles - Research Relativ e to Ocean Geodynami c Cycles

Principa l Investigato r D r. Willia m S.F. Kid d

Associate Professor

Department of Geologica l Science s

SUNY Alban y

1400 Washingto n Avenu e

Albany , New Yor k 1222 2

Grantee Institutio n : T h e Researc h Foundatio n o f SUN Y

on Behal f of SUN Y at Alban y

P. C. Box 9

Albany , New Yor k 12201

Loca l no . 320-1514 A

(NASA-CR-176560) WILSON STUDY CYCLES:

fiESEABCH RELATIVE TO .OCEAN fiECDYNAHIC CYCLES

Final Report, 1 -Jul. 1983 - 5 Bay 1985

(State Oniv. ,of New York) 23 p

HC A02/MF A01

N86-21092

°

5564

,r
o

Final Report for NASA Grant No. NAG-5333 (Research Foundation SUNY No. 320-5141A)

"Wilson Cycle Studies"

Five topics dealing with different aspects of the plate tectonic process, and

their effects on the long-term development of the continental lithosphere of

this planet, were studied during this project.

1. Conversion of Atlantic (rifted) margins to convergent plate boundaries.

An extensive literature search and compilation was done on the geology of

21 originally Atlantic-type margins, whose rifting age ranges from Neogene (30

m. y. ) back to about 2000 m. y. in the early Proterozoic, that is to one of the

earliest easily recognizable rifted margin sequences preserved in the geological

record. Of the 21 examples (Table 1), 19 show definite evidence, in the form of

distinctive stratigraphic sequences, and characteristic relative timing of

magmatism and structural deformation, of conversion by collision with an island

arc and/or microcontinental fragment, not by the direct initiation of subduction

beneath a previously passive Atlantic-type continental margin. Only two

examples show evidence, derived from the same kind of data as the others, for

direct initiation of subduction at a previously passive margin. Both of those

are cases where a narrow, laterally extensive microcontinental fragment with

passive margins on both sides collided with a subducting margin. Convergence

was transferred from the earlier subduction zone, across the microcontinental

object, to the passive margin on the other side. Passive margins developed on

large continents were in no case found to change directly into Andean convergent

margins. Even in the two cases of microcontinents where direct conversion did

happen, the age of rifting of their margins was not a large amount older than

the age of collision of the microcontinent across the first subduction zone.

Thus, the oceanic lithosphere adjacent to the passive margin of the
O

Page 2

microcontinent that was converted to a subducting margin was young, warm, and as

a result, thin and relatively weak. Margins of similar type (with a narrow

microcontinent involved) with a significantly greater span between rifting and

convergence were not found and are thus not among the 21 cases studied. It

would be of considerable interest to try to find such examples to test whether

the direct conversion to Andean margin is more a function of age of oceanic

lithosphere adjacent to the margin or to the specific geometric constraints of

\

such microcontinental collisions.

Future work is probably needed to test the hypothesis that we put forward

from this study that Atlantic-type margins do not generally convert directly to

Andean margins (Burke, Kidd and Bradley, 1984; m. s. in preparation; Figs. 1-5

and Table 1 from part of this m. s.). Many of the examples we use have a

limited Andean history subsequent to conversion and before a major continental

collision event closed the particular oceanic tracts involved. The passive

margin sequences and their fate are, as a result, relatively easy to recognize.

Where extensive Andean magnatism (and deformation) has occurred, the earlier

passive margin geology can become much harder to decipher. These kind of

margins with an extensive Andean history are, however, the kind of which

additional examples are most needed and study of which will form the best test

of the hypothesis derived from this work.

2. Oceanic plateaus and their fate at subduction zones

There are oceanic plateaux of several distinct types, all, however, being

distinguished by above average elevation relative to the ocean floor age where

they are located and, in we 11-documented examples, possessing significantly

thicker crust than normal ocean. They include microcontinents (e. g. Rockall,

Seychelles) variably thinned from normal continental thickness, and (less

abundant) extinct arcs (e. g. Shirshov Ridge). However, the most abundant type
Page 3

of oceanic plateau, especially in the western Pacific, are the varieties that

have been constructed by hot-spot-type magnatism, producing objects ranging in

large-scale form from the Hawaiian-Emperor Ridge to the Ontong-Java plateau. In

some circumstances these plateaux sustain a substantial carbonate bank

accumulation (e. g. Bahamas). There appears to be a direct relation, shown best

by Iceland, between large hot-spots, the generation of hot-spot-type oceanic

plateaux, and flood basalts and continental dike swarms. Both from this

connection and the observation that many of these plateau were formed, like

Iceland now, on spreading center axes, it can be concluded with confidence that

the bulk composition of these plateaux is basaltic. Geophysical measurements

are wholly consistent with this general notion. Small samples preserved in

subduction accretion prisms (e. g. Malaita) confirm that basalt sills are a

major component of the upper part of s'cme, and limited direct sampling by DSDP

drilling is also consistent with this.

Livaccari et.al (1981) suggested that subduction of an oceanic plateau, a

pair to the present Hess Rise (Fig. 6) occurred under western North America

65-40 m. y. ago contributing to the Laramide orogeny through the abnormal

buoyancy it created in the subducting plate. Burke et al (1978) identified most

of the Caribbean as floored by a presently hard-to-subduct oceanic plateau, but

this example leaves open the question whether the plateau will be subducted in

the future. Two questions related to oceanic plateaux were addressed in this

study, derived from the suggestions summarized above. One concerns the

inference that the general and usual fate of an oceanic plateau is to be

subducted; the other is whether, if remnants of plateaux can be found in older

orogenic belts, the timing of their arrival can be correlated, like in western

North America, with Laramide-like orogenic effects.
Page 4

There seems little doubt from the rarity in erogenic belts of lithologic

sequences appropriate for derivation from oceanic plateaux that almost all of

them have been subducted, at least below the level generally exposed in the

crust. Only two possible examples have been clearly identified besides those in

the Caribbean and the fragment of the Ontong Java plateau in the Solomon

Islands. These two examples are in Alaska, previously described as ophiolite,

and forming a large proportion of the terrane called Wrangellia in British

Columbia and southern Alaska. The latter example is somewhat dubious in that

the field relations currently described have the potential plateau rocks in

stratigraphic contact above a Paleozoic island arc assemblage. If the contact

is a regional overthrust, which seems possible, it is a good candidate for a

remnant of an ocean plateau, but field work would be needed to establish this.

Otherwise it would be a rift-event flood basalt assemblage sited within an older

convergent arc. Since so few examples have been identified, and the geological

relations of these two with their surroundings are not well established, no

valid inferences can be made about possible effects of changes in orogenic

activity correlated with their arrival at a convergent margin. At least some of

the difficulty we encountered in finding possible remnants of oceanic plateaux

is perhaps due to mistaken field relations reported in available literature,

lack of detailed investigations in others, and inappropriate grouping of

plateau-derived magnetic and sedimentary sequences with other unrelated ones.

However, at least part must be a real absence reflecting efficient eventual

subduction of the plateaux, despite the Caribbean's present pause before

descent.

A short publication discussing these findings is planned, but is not yet in

an advanced stage of preparation, being given lower priority in the light of the

somewhat negative findings.
Page 5

3. Continental Collision and Tectonic Escape

Collisional studies have proved one of the most productive parts of these

Wilson Cycle studies. Reviews have been made of the Cenozoic geology of the

Caribbean area, the Aegean and Turkey, the Carpathian-Pannonian area and

Mongolic-China, together with late Mesozoic eastern Asia-SE Asia, and a similar

area for the late Tressic, and Pan-African events for most of Africa and Arabia.

All of these collisional events show the importance of tectonic escape and

the development of very large strike-slip fault systems during this process.

Because of the complexity of the geology in most of these areas, the importance

of the tectonic escape process during collisions had not been fully realized

until this comparative study. Publications deriving in whole or in part from

this portion of the project are Burke (1983), and Sengor and Burke (1986).

4. Rift Studies

Studies of southern Africa rifts, done partly under the support of this

grant, were most productive and enlightening on the nature of tectonic activity

in the later Archean and the condition of the continental lithosphere at that

time. The Pongola structure appears to be the earliest (^3.0 Ga) rift, with

properties like those of younger ones, preserved on this planet (Burke et al

1985a - see attachment). Similarly, the Ventersdorp rift system, of latest

Archean age, also has properties like those of modern rifts, and can plausibly

be linked to the effects of collisional tectonics in the Limpopo erogenic belt.

(Burke et al. 1985b - see attachment). The third supposed rift investigated in

southern Africa, the Witwatersrand structure, turned out from our assessment not

to be a rift at all (Burke et al. in press, Tectonics - see attachment).

However, its' identification as a foreland basin (of an age older than 2.6 Ga)

is of considerable significance in the understanding of the nature of

continental lithosphere in the later Archean and the tectonic regime operating
Page 6

at that time. As its properties are much like well-studied young foreland

basins, the implications of the operation at that time of pi ate-tectonic

processes, and the existence of continental lithosphere of thickness not

substantially different from now, are important conclusions.

Studies of along-strike variations in modern rifts were not so fruitful.

Unless additional new data is obtained, unambiguous conclusions will be

difficult to reach on the causes of the observed variations.

5. Hot-spot studies

A previous compilation of the global hot-spot distribution by us did not

include any that might occur within convergent plate boundary zones since

alkalic vulcanism within those zones could not unambiguously be attributed to

other than shallow mantle or crustal processes. A study of some of the

occurrences within convergent zones to see if such an attribution could be made

was one of the purposes of these Wilson cycle studies, together with a review

and revision of the overall hot-spot list. No unambiguous criteria were found

that would enable discrimination on a routine basis of hot-spot-like alkalic

volcanism from that unrelated to hot-spots. Major element geochemical and

petrographic data readily available for most or all occurrences shows no single

one or combination of factors that might be used. While it is possible that

isotopic or rare earth data could be helpful, this is not available for enough

examples to make a meaningful judgment. The only criterion that showed a

possibility for application is the identification of a "hot-spot track", or

systematic progression of vulcanism crosscutting the convergent zone on seme

consistent trend, the same feature that enables identification of many hot-spot

tracks outside such zones. However, it is difficult to pick out the

compositionally distinctive volcanics of the hot-spot from the background

convergent plate boundary vulcanism except when the volcanics are young and
Page 7

fresh. There are two reasons why this is so: first, because erosion or burial

in these tectonically active zones readily obscures the older record of the

track, and second because alteration of volcanics, ubiquitous in arc terrains,

makes it much more difficult to recognize the different hot-spot lavas in the

first instance. Thus, they may be present, but unreported, in many places.

There is also the problem that no preexisting identifiable base level usually

exists in the tectonically active regions of convergent plate boundaries to

allow detection of the characteristic domal uplift that is seen to accompany

hot-spots in intra-plate regions and along divergent plate boundary systems.

Thus, even the detection of active hot-spot centers within convergent boundaries

is problematical, and is likely to remain so until much more systematic

field-based investigations are made. It is apparent that with detailed

knowledge, hot-spot tracks can probably be identified in these zones; one

example that may be connected with passage of the Yellowstone hot-spot across

the California-Oregon border region is the existence there of kimberlite and

related features (C. Blake, pers. comm. ). These, however, are at present too

poorly dated to be tied with confidence to the hot-spot track.

The two examples proposed for investigation in the original proposal, the

Rhine Graben spot, and the French Massif Central, yielded less than expected.

No identifiable trace of the Rhine Graben vulcanism is known south of the Alpine

foreland basin; the conclusion of Sengor et al. (1976) that the Graben was

generated by the Alpine collision is most consistent with this observation. In

the case of the Massif Central, Miocene rifting and dispersal of the crustal

pieces that used to lie in the general direction of the projected hot-spot track

make any identification of it troublesome. While it is entirely possible that

the rifting could be connected with hot-spot passage, it is hard to establish

this with confidence, and the former possible position of the hot-spot is very

poorly constrained. The problem of young isotopic ages within the old part of
Page 8

the Massif Central track, and rather old ages as well as recent ones at the

young end of the Rhine Graben track, remains a problem. Since all the ages are

determined by the K-Ar technique, sane a long time ago, the possibility of

excess Argon, loss of argon by subsequent thermal events, and analytical

inadequacies all exist, but cannot be identified from the original data. New

precise ages are clearly needed to resolve this problem and this fell outside

the scope of this research.

A revised global hot-spot list was generated through selective literature

search (Table 2). Even though areas of convergent tectonism could not be

included, the list is significantly improved over the previous list, because of

better understanding of the variability in size of different hot-spots. The

previous list had been constructed with criteria that minimized the variation.

Similarly, better understanding now exists of the tectonics of secondary

extension structures associated with large strike-slip fault systems, allowing a

number of items to be placed in the category where magnatism appears to be a

secondary effect, or passive response to lithospheric extension. Consequently,

the list of presumed active mantle hot-spots is better established. Preparation

of a manuscript documenting the list is in its early stages.
Page 9

Bibliography - papers on research funded in part or Wholly by NAG-5333

Burke, K., 1983. Four billion years of allochthonous terranes. EOS, Trans. Amer.

Geophys. Union, 64_, 844.

Burke, K.C., Kidd, W.S.F., and Bradley, 1984. Do Atlantic-type margins convert

directly to Andean margins? Geol. Soc. Amer. Abstracts with programs, 16,

459.

Burke, K.C., Kidd, W.S.F., and Kusky, T.M., 1985a. The Pongola structure of

Southeastern Africa: the world's oldest preserved rift? T. Geodynamics, 2^

35-49.

Burke, K.C., Kidd, W.S.F., and Kusky, T.M., 1985b. Is the Venterdorp rift system

of Southern africa related to a continental collision between the Kaapvaal

and Zimbabwe cratons at 2.64 Ga ago? Tectonophys., 115, 1-24.

Burke, K.C., and Sengor, A.M.C., 1986. Tectonic Escope in the evolution of the

continental crust. Amer. Geophys. Union, Geodynamics Ser. 14, Reflection

Seismology: the continental crust, pp. 41-53. Amer. Geophys. Un.

Washington.

Burke, K.C., Kidd, W.S.F., and Kusky, T.M., in press. Archean foreland basin

tectonics in the Witwatersrand, South Africa. Tectonics.

jn Preparation

Burke, K. Bradley, L. and Kidd, W.S.F., Do Altantic-type margins convert

directly to Andean margins?
Collision Zone

Timor

Taiwan

Zagros

Bitlis

Carpathian

Himalayan

Pontide

Cuba

Oman

Brooks Range

Chirsky

Venezuelan coast

Ouachita

Antler (Nevada, Utah)

Taconic

Franklinian

Dahomeyan

Coronation

Cape Smith/Lab Trough

Caledonides (Scand.)

Urals

Age of

Atlantic-Type Side Approximate Age Convergent Side Coll.s.on

of Rifting JnMa

Australia

China

Saudi Arabia

Arabia

Poland, Ukraine

Sou/hern Tibef

S. Cimmeria

Florida

Arabia

North Slope Alaska

Siberia

S. America

N. America

N. America

N. America

N. America

West African Craton

Slave Province

Superior Province

Baltic Shield

Russian Platform

150

30

290

450

180

600

180

160

600

350

370

150

600

800

600

600

1100

2100

2000

650

650

Banda Arc

Phillipmes

Iran

Taurides

Hungary

Southern Tibet

S. Cimmeria

Cuba

Buried Arc

Yukon-Koyukuk Terrane

Omolon

Off Shore Islands ' '

Yucatan (?)

Buried Arc

Bronson Hill, Miramichi

N. Ellesmere Island

Dahomides

Bear Province

Churchill Province

East Greenland

Siberia

Now

Now

Now

10

10

40

40

50

80

120

170

80

300

350

450

370

600

'1700

1875

425

290

Duration of

Rifted Margin

160

30

210

590

170

560

140

80

520

250

230

70

300

450

150

230

500

400

125

225

360

o

NAG-5333 Final Rept. Table 1.
Lias U95-

176 ma)

Paleo Tethys I Cimmerian Continent

Arda congl.

Neo Tethys I Anatolide-Tauride

northern branch platform

Dogger

176-160ma)

.Continental AssemblageMylonites Dogger deposition

v v V V V V.

Granodiorites,

Quartz Monzonites

Black Sea

Late Cretaceous -

late Eocene

(100-37 ma)

Eastern Pontides Anatolides

Oligocene -

medial Miocene

(37-15 ma)

O North Anatolian Transform

(dextral strike slip at present)

ATLANTIC MARGIN IN PONTIDES CONVERTS TO ANDEAN

IN LATE CRETACEOUS (BASED ON SENGOR)

NAG-5333 Final Rept. Fig. 1
o

ORIGINAL PAGE 18

Of POOR QUALITY

50*S 4O 30 20 1Q O 10 20 30 40 SO' N

> i i i i | t i ii i

OUANTANG

INDIA LHASA

Gulu Anduo

continental thruct* Takana

M,

120 My

100 My

80 M,

60 My

Kangmar

continental thrust

40 My

My

Present

I KS (SU3)

BNS (SU2)

ITS(SU1)

SO*S 40 30 20 10 0 1O 20 3O 40 SO'N

AN INTERPRETATION OF THE EVOLUTION OF

SOUTHERN TIBET BY ALLEGRE AND MANY OTHERS

NATURE JANURY 1984

NAG-5333 Fund Rept. Fig. 2
AXI «JS

S OUTE OUTERR SWEL SWELLL ENVIRONMENT DEPOSITION HAL|W

ORIGINAL PAGE (S

OF POOR QUALfTY

A. EARLY CRETACEOUS

UNCONFORMITY AT TOP

HAJAR SUPER-GROUP

HALIW AND HALFA

HAMRAT DURU ft MELANGE

-WAHRAH ,

B. LATE TURONIAN - EARLY CONIACIAN

MUD DEPOSITION

C LATE CONIACIAN

FAHUO ^FIQA DEPOSITION xMUTI_DEPOSITION

FAHUO

FAHUO

E. SANTONIAN-CAMPANIAN

•JUWEIZA DEPOSITION

F. EARLY MAESTRICHTIAN

MW-PLIOCENE

SIMSIMA- PALEOGENEFIOA

HAJAR SUPER-GROUP

FHUD NATIH

OMAN EXOTICS

MAESTRCMTIAN-FttLEOGENE

G. PRESENT NO VERTICAL EXAGGERATION

LEGEN D

( I SANDSTONE (T7

T

1 CHERT

fj^q SHALE H"^ TUFF

CALCAREOUS TURBIWTES Fn ICNEOUS FLOW

CALCAREOUS TURBIOITES FT'Tj CONTINENTAL CHUST

AM) PELAGIC SHALE

^^ SHELF LIMESTONE

FvFl ABYSSAL LIMESTONE ^B MANTLE

LAYER 2

LAYER J CRUST OMAN FROM GEALEY (1977)

NAG-5333 Final Rept. Fig. 3
B

/

Cold, thick, strong

0 100 km

/

Hot, weak, thin

Maximum sediment

load of 16 km

LITHOSPHERE

Mantle

100km

o

c

100km

CROSS SECTION THROUGH ATLANTIC TYPE MARGIN A) UNDEFORMED

B) FAILING AT MARGIN IN COLD, STRONG LITHOSPHERE C) FAILING

OF OCEANIC LITHOSPHERE AWAY

NAG-5333 Final Rept. Fig. 4
Age of Margins at time of

Continental Collision

100

o

200 300 400

AGE, My

500 600

HISTOGRAM OF AGE OF MARGINS AT TIME OF CONTINENTAL

COLLISION SUGGESTING NO CORRELATION BETWEEN AGE

OF MARGIN AND STABILITY OF MARGIN

NAG-5333 Final Rept. Fig. 5
rr

NAG-5333 Final Rept. Fig. 6

n>4-. <.9W ' •^•*..~?..- '. '

110-135 mybp a)

^^ Laramide

Foreland

80 mypb b)

a) HESS RISE AND ITS TWIN FORMED

AT KULA-PACIFIC SPREADING

CENTER DURING THE EARLY

CRETACEOUS.

b) HESS RISE TWIN APPROACHING

NORTH AMERICA DURING THE

'LATE CRETACEOUS.

Farallon Plate

BHBB

Oceanic Plateau

80-65 mybp

•High Angle

Subduction

PRE-LARAMIDE

CONVERGENCE STYLE

65-40 myb?

Strixftuction

SUBDUCTION OF THE

HESS RISE TWIN AS A

POSSIBLE INFLUENCE

ON LARAMIDE OROGENY.
o

-1-

HOT SPOTS -- WORLD LIST

NAG-5333 Final Report — Table 2

Hot spots defined on the basis of both a structural or topographic uplift

(anomaly) and associated vulcanism of alkaline type (distinct from normal

spreading ridge vulcanism and from tholeiitic flood basalt). On spreading

ridges, excess vulcanism occurs compared with normal segments (e.g.

Iceland). Size of hot spot, defined by diameter of uplift or of anomalous

vulcanism, is typically about 200 km, but ranges from about 100 km to about

500 km. This finite width requires hot spot tracks to be defined by swaths

of the width of the hot spot; a narrow line is not justified by the data

and conceals the possible errors in determination of the position. Groups

of a few hot spots may be defined by topographic swells in places (e.g.

East African Swell), but only a minority can be joined in this way.

Notations

* Oceanic lithosphere (for within plate hot spot only)

C Continental lithosphere (for ridge axis hot spots only)

Q No volcanic evidence - proposed only from ridge axis topography

r Associated with a live rift

Y In vicinity of RRR, RRT or RRr triple junction

I Impactogenal origin proposed (usually with r)

T In zone of secondary tectonics associated with primary transform

plate boundary

1,2 etc Number of swell hot spot belongs within (1-East African,

2-Ethiopian, 3-Red Sea, 4-Colorado Plateau, 5-Azores)

Plate abbreviations:

APR = Africa

ANT = Antarctica

ARA = Arabia

COC = Cocos

EUR = Eurasia

GOR = Gorda

IND = Indo-Australian

NAM = North America

NAZ = Nazca

PAC = Pacific

SAM = South America

In divergent boundary hot spot list, if hot spot appears off-axis, plate(s)

on which hot spot lies underlined.
A. Hot spots on or

No. Notations

0

1

2

3 5

4 Y5

5 5

6

7

8

9

10 Y

11

12

13

14 Q

15 Q

16 (Y)

17

18

19

20

21

22 (c)3

23 YC2

24 YC2

25 YC2

O " O

near diverqent or ridqe-transform-ridqe plate boundary segments

Name

Yermak

Jan Mayen

Iceland

45°N Atlantic

Azores

Colorado Smt.

Ascension

St. Helena

Tristan/Gough

Discovery Smts.

Bouvet

Prince Edward/Marion

Rodriguez

St. Paul/New Amsterdam

Natural iste

Kangaroo

Balleny

Easter

Galapagos

Revillagigedo

Explorer Smt.

Bowie Smt.

Harrat Er-Raha

Aden

Danakil

Awash

Coordinates

84N, 0

71N, 09W

65N, 16W

44N, 28W

38N, 27W

34N, 38W

OSS, 14W

16S, 06W

38S, 11W

46S, 08W

54S, 03 E

47S, 38E

20S, 62E

39S, 78E

48S,105E

49S,135E

67S,163E

27S.109W

0, 91W

19N,111W

49N,132W

53N,136W

27N, 36E

14N, 46E

15N, 41E

ION, 41E

Plates

EUR/NAM

EUR/NAM

EUR/NAM

EUR/NAM

EUR/AFR/NAM

AFR/NAM

SAM/AFR

AFR/SAM

AFR/SAM

AFR/SAM

ANT/AFR/SAM

ANT/AFR

AFR/IND

ANT/IND

ANT/IND

ANT/IND

ANT/PAC/IND

NAZ/PAC

NAZ/COC

PAC/NAM/COC

PAC/GOR

PAC/NAM/GOR

ARA/AFR

ARA/AFR

AFR/ARA

AFR/ARA
-3-

B. Hot soots within plates

1. Africa

26 r2 S. Wonji 07N, 38E APR

27 rl Nakuru 0, 36E APR

28 rl Kilimanjaro 03S, 36E APR

29 rl Nyiragongo 01S, 29E APR

30 rl Rungwe 09S, 34E APR

31 * Vema Smt. 33S, 08E APR

32 * Madeira 33N, 17W APR

33 * Canary 28N, 15W APR

34 Anti-Atlas 31N, 07W APR

35 * Cape Verde 16N, 24W APR

36 Dakar 15N, 18W APR

37 Air 18N, 09E APR

38 Ahaggar 24N, 06E APR

39 ' Tripoli 32N, 13E APR

40 Jebel Sawda 29N, 15E APR

41 Haroudj 28N, 17E APR

42 In Ezzane 23N, HE APR

43 Tibesti 23N, 18E APR

44 Jebel Uweinat 23N, 25E APR

45 Bayuda 18N, 33E APR

46 Jebel Marra 14N, 25E APR

47 Biu UN, 12E APR

48 Jos Plateau ION, 09E APR

49 Adamawa 06N, 10E APR

50 Ngaoundere 06N, 13E APR

51 Cameroon 04N, 09E APR

52 * Sao Tome/Annobon 0, 06E APR

53 * Comores 12S, 44E APR

54 Cap d'Ambre 14S, 49E APR

55 Central Madagascar 20S, 47E APR

56 * Reunion/Mauritius 21S, 56E APR

57 *5 Great Meteor Smt. 31N, 29W APR

58 Lesotho 29S, 29E APR
-4-

2. Antarctica -- (most continental hotspots in Antarctica defined only by

volcanic occurrences -- uplift information lacking --

identification tentative. Several may be associated with

ice-buried rifts.

59 *

60

61

62

63

64

65

66

67

68

69

70

71

72 *

73 *

74 *

3. Arabia

3

3

75

76

77

78

4. Cocos

79

Peter 1st Id.

Merrick Mtns

Alexander

Hudson/Jones Mtns.

Murphy/Crary Mtns.

Mt. Siple

Ames/Flood Ranges

Executive Committee Range

Fosdick Mtns.

Mt. Early

Mt. Erebus

Mt. Mel bourne/Adare Pen.

Gaussberg

Heard

Kerguelen

Crozet

Mecca

Medina

Damascus

Diyarbakir

Cocos

5. Eurasia - a) West of zone affected by India-Asia collision tectonics

80

81 Ir

Massif Central

N. Rhine Graben

69S, 91W

75S, 72W

72S, 70W

74S, 97W

77S.115W

73S.126W

76S.135W

78S,126W

77S,144W

87S,153W

78S,167E

73S,170E

67S, 89E

53S, 74E

49S, 70E

47S, 52E

22N, 42E

26N, 41E

33N, 37E

37N, 39E

05N, 87W

a collision

46N, 03E

51N, 08E

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ANT

ARA

ARA

ARA

ARA

COC

tecti

EUR

EUR
-5- -^

5. Eurasia - b) In zone affected by India-Asia collision tectonics

82

83

84

85

86

87

88

89

90

91

92

6.

7.

93

94

95

96

97

8.

98

99

100

101

102

103

104

105

106

107

Ir Baikal/Irkutsk

Ir NE Ordos Plateau

I(r) Ara Hangay

I Vitim Plateau

Nen-Chiang

I SW Hsing-An

Ir Soeul/Wonsan

Cheju

- c) SE China-Indochina block

Hainan

SE Laos-Vietnam

Borneo

Gorda - none except on spreading ridge

Indo-Australia

N. Queensland

W. Victoria

* Tasmantid Seamounts

Lord Howe Rise

Norfolk

North America

Balagan Tas/Indigirsky

Anjuisky

St. Lawrence

Nunivak

Seward Peninsula

T Mt. Edziza

r Yellowstone/Snake River

4 Flagstaff

r4 Santa Fe

r4 Rio Grande/Big Bend

52N,104E

40N.114E

48N,100E

54N,113E

49N,125E

45N,115E

39N.127E

33N,126E

21N,110E

14N,108E

01N,113E

boundary with PAC

20S,145E

38S,143E

39S.155E

36S,160E

29S,168E

67N,144E

67N,165E

64N,170W

61N,165W

66N,160W

58N,131W

44N,112W

35N,112W

36N,106W

30N,105W

EUR

EUR

EUR

EUR

EUR

EUR

EUR

EUR

EUR

EUR

EUR

(see above)

IND

IND

IND

IND

IND

NAM-or (NAM/EUR)

NAM

NAM

NAM

NAM

NAM

NAM

NAM

NAM

NAM
9. Nazca

10. Pacific

o -6-

108 *

109 *

Isla San Felix

Is!a Jan Fernandez

26S, SOW NAZ

34S, 81W NAZ

110

111

112

113

114

115

116

117

118

119

120

121

122

123

T

T

T?

T?

T?

*r?

*

*

*

*

*

*

*

*

E. Otago

Banks Peninsula

Chatham Id.

Campbell Id.

Antipodes Id.

Samoa

Caroline

Hawaii

Guadalupe

Rarotonga

Tahiti

Marquesas

Macdonald Seamount

Pitcairn/Gambier

46S,173E

44S.174E

44S.176W

52S,169E

50S,179E

14S,172W

05N,164E

20N.155W

29N.118W

22S,158W

18S,148W

11S,138W

29S,140W

27S,120W

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

PAC

11. South America

No. Notations Name Coordinates Plates

124 *

125 *

Fernando de Noronha

Trinidade/Martin Vaz

04S, 32W SAM

21S, 28W SAM