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Pergamon J. Geodymxmics Vol. 23, No. 314, 223-235. 1997 pp.
8 1997 Elsevier Science Ltd
All rights reserved. Printed in Great Britain
PII: so26&3707(%)ooo464 0264-3707/97 $17.C0+0.CK1
THE ASSEMBLY OF GONDWANA 800450 Ma
JOSEPH G. MEERT’ and ROB VAN DER VO02
’ Indiana State University, Department of Geography and Geology, Terre Haute, IN 47809, U.S.A. and
2 University of Michigan, Department of Geological Sciences, Ann Arbor, MI 48109, U.S.A.
(Accepted in revised form 25 July 19%)
Abstract-The formation of the supercontinent Gondwana heralded the beginning of the
Phanerozoic following a complex series of collisional events after the break-up of earlier
supercontinental assemblages. Paleomagnetic data are used to help distinguish between these
events and it appears that there are three critical periods of mountain building during Gondwana
assembly. The first major erogenic event took place between 800 and 650 Ma and has been
termed the East Africa Orogeny. This tectonic episode formed the Mozambique Belt and likely
resulted from the collision of India, Madagascar and Sri Lanka with East Africa. The second and
third erogenic periods during Gondwana assembly partially overlap in time. The Brasiliano
orogeny (600-530 Ma) resulted in the amalgamation of the South American nuclei and Africa.
The Kuunga Orogeny was proposed, in part, because of the recent collection of geochronologic
data indicating a 550 Ma granulite forming event in East Gondwana and the observation that the
apparent polar wander path for Gondwana does not form a spatially and temporally coherent
pattern until roughly the same time. The Kuunga orogeny may have resulted from the collision
between Australia and Antarctica with the rest of Gondwana. 0 1997 Elsevier Science Ltd
INTRODUCTION
The remarkable fit between the east coast of South America and the west coast of Africa led
directly to the first postulates of continental drift (Wegener, 1912). These two continents were
considered part of a larger landmass that was composed of most of the present-day southern
continents and given the name Gondwana (literally “Land of the Gonds”; Fig. 1). Much is
known about the Mesozoic break-up of Gondwana, but the Paleozoic and Neoproterozoic
tectonic history of Gondwana is obscured, in part, by a lack of paleomagnetic data to help
constrain continental motion. In particular, the sequence of tectonic events that led to the
assembly of Gondwana have, until recently, been lumped under the name “Pan-African
erogenic cycle”. Recent hypotheses linked the formation of Gondwana to the break-up of a
larger supercontinent called Rodinia about which the fragments of Gondwana were distributed
(Fig. 2; McMenamin and McMenamin, 1990; Dalziel, 1991, 1992; Hoffman, 1991). One of the
key tectonic elements of Gondwana is the Mozambique Belt in East Africa (Fig. 1). This
800-650 Ma erogenic belt was originally interpreted as the suture between East (India,
Madagascar, Antarctica, Australia) and West (Africa, South America) Gondwana, formed during
part of the larger Pan-African erogenic cycle (Burke and Dewey, 1972). Recent geochronologic,
paleomagnetic and geologic investigations in Gondwana have led to the recognition of at least
223
224 J. G. Meert and R. Van der Voo
three distinctive episodes during the formation of Gondwana (Kroner, 1993; Castaing er al.,
1994; Villeneuve and Comee, 1994: Stem, 1994 and references therein; Meert er al., 1995;
Meet? and Van der Voo, 1996). These orogenies are referred to as the East African Orogeny
(650-800 Ma; Stem, 1994), the Brasiliano Orogeny (660-530 Ma; Villenueve, 1994) and the
Kuunga Orogeny (=550 Ma; Meert er al., 1995). The Brasiliano belts record the collisions
between the south American cratonic nuclei and the African nuclei (Rogers et al., 1995;
Castaing et al., 1994; Villenueve et al.. 1994; Unrug, 1992) and the East African and Kuunga
belts resulted from collisions between the East Gondwana blocks and Africa (Stem, 1994; Meert
et al., 1995; Meert and Van der Voo, 1996). Detailed investigation of these orogenies reveals a
more complex spatial and temporal pattern of events yet each is clearly related to the final
____...........; . . . . . . . . . . ..___._._._ I.
~ ,,,, j,, ~; ,,,,,;;, gy
. . . . ::>. i ,,.:‘__.,. .s
Fig. 1. The supercontinent Gondwana in African coordinates using the euler rotation poles of de Wit et al.
(1988). The location of the Mozambique erogenic belt long known as an important tectonic feature related
to the assembly of Gondwana is shown. West Gondwana is outlined using solid lines and East Gondwana
is depicted using dashed lines.
The assembly of Gondwana 800-550 Ma 225
formation of the Gondwana continent. Of particular interest are the numerous 550 Ma ages
reported from southern India, southern Madagascar, Sri Lanka, Mozambique and parts of East
Antarctica associated with granulite formation (Shiriashi et al., 1994; Unnikrishnan-Warrier et
al., 1995; Windiey et al., 1994; Kroner, 1993; Kroner et al., 1996). This granulite-facies
metamorphism is clearly younger than collisional events in East Africa and the Arabian-Nubian
shield which are dated to between 650 and 800 Ma (Maboko et al., 1985, 1990, 1995; Stem,
1994 and references therein). Assuming these younger (~550 Ma) ages to be related also to the
continent-continent collision between that region and East Gondwana, then what do the two age
groups indicate about the sequence of orogenies in this part of Gondwana? Do they suggest that
there were two distinct continent-continent collisions in this region of Gondwana, or are the
younger ages merely the result of the extensional collapse of the Mozambique Belt? The
Fig. 2. The supercontinent Rodinia reconstructed to its paleographic position at 750 Ma according to the
euler rotation poles of Dalziel(l992).
226 J. G. Meert and R. Van der Voo
suggestion is made here that the available geochronologic and paleomagnetic data can be
interpreted to support the formation of this part of Gondwana during two distinct orogenies. The
terminology of Stem (1994) is followed by referring to the earlier erogenic episode
(650-800 Ma) as the East Africa Orogeny while using the previously suggested name of
Kuunga Orogeny for the younger erogenic episode (550-530 Ma; Meert et al., 1995).
THE BREAKUP OF RODINIA
The formation of the supercontinent Rodinia in the Neoproterozoic (= 1100 Ma) predates the
formation of Gondwana and, if the configuration of Dalziel (1992) is correct, it provides
important geometric and geochronologic constraints on the formation of Gondwana. Powell et
al. (1993) and Torsvik et al. (1996) both used the available paleomagnetic data from Laurentia
and East Gondwana to suggest that the rifting of Australia/Antarctica from (present-day)
western Laurentia began at about 720 Ma despite a gap in the paleomagnetic data (Fig. 3; Table
1) from both continents between 720 and 600 Ma. The timing of this rifting broadly coincides
LAUREN
BALTICA
Cambrian
0 060 120
Fig. 3. The apparent polar wander paths for Laurentia, Baltica and East Gondwana rotated to a Rodinia
configuration (Baltica coordinates; after Torsvik et al., 1996). The fit of Baltica is slightly modified from
the Dalziel configuration and uses a rotation pole at 72”N. 43”E, - 50”. The paths for Baltica and Laurentia
are cubic sphne fits to the data listed in Table 1 and the East Gondwana path is taken from Powell et al.
(1993) and rotated to Bahica coordinates. The apparent polar wander paths are consistent with two phase
rifting of Rodinia (see text).
Table 1. Listing of paleomagnetic poles from 8 1 O-505 Ma
Pole Age (Ma)* Pole Pole A95 or Rotated to Rotated to
Q-value error latitude longitude &X Dalziel 1992 Gondwana Reference
CONGO CRATON
I. Gagwe lavas
2. Mbozi complex
PAN-AFRICAN BELTS
ADJACENT TO CONGO
CRATON
3. Sinyai dolerite
4. Ntonya ring
RIO PLATA CRATON
5. La Tinta fm
INDIA
6. Hamhalli dikes
7. Malani rhyolites
8. Bhander and rewa S.S.
9. Purple sandstone
10. Jutana fm-Pakistan
11. Salt pseudomorph’s
EAST ANTARCTICA
12. Sor Rondane intrusions
CENTRAL AUSTRALIA
13. Mean pole
14. Mean pole
15. Mean pole
SEYCHELLES
16. Mahe granite
BALTICA
17. Mean pole
18. Mean pole
19. Mean pole
20. Mean pole
21. Mean pole
5
5
5
4
5
3
6 550* 15
6 530* 15
6 510+ 15
3
810+25 25”s
743*30 46”N
547*04
522k 13 29”s
28”N
709+24 80”s
814_+34
729k 10
550*30
530* 15
530* 12
523*24
15”N
81’S
51”N
28”N
21”N
27”N
a-515 28”s
45”s
36”s
26’S
683& 16 54”N
750+ 15
650~ 15
580~ 15
565* 15
553+ 15
28”s
25”N
68”N
57”N
49”N
273”E
325”E
319”E
345”E
30l”E
056”E
224”E
217”E
212”E
231”E
214”E
010”E
346”E
005”E
022”E
38”E
017”E
051”E
098”E
14l”E
147”E
10”
09” 38”N. 003”E Fixed Meert et al., 1995
4O”S, 325”E Fixed Meet? et al., 1995
05” NR
02” NR
05” 14”N, 254”E 5 1 “S, 063”E
06”
10”
11”
12”
11”
5”
02”N. 03 1 “E 06”N, 036”E
16”S, 342”E 42”N, 099”E
NR 23”S, 333”E
NR 05”s. 348”E
NR 14”S, 005”E
NR 06”s. 350”E
3” NR
13” NR
18” NR
18” NR
02”
09”
15”
11”
15”
12”
23’N. 336”E 64”N. 063”E
16’S, 325”E NR
28”N, 010”E NR
57”N, 072”E NR
42”N, 097”E NR
34”N, 101”E NR
Fixed Meert and Van der Voo, 1996
Fixed Btiden et al., 1993
12”N. 013”E Zijderveld, 1968
12”s. 343”E Meert and Van der Voo, 1995
02”N, 35 1 “E Meert and Van der Voo, 1995
17’N, 0Ol”E Meert and Van der Voo, 1995
Valencio et al., 1980
Dawson and Hargraves, 1994
Klootwijk, 1975
McEIhinny et al., 1978
McElhinny, 1970
Klootwijk et al., 1986
Wensink, 1972
Suwa et al., 1994
Torsvik et al., 1996
Torsvik et al., 1996
Torsvik et al., 19%
Torsvik et al., 1996
Torsvik et al., 1996
Table 1. Continued
Pole Age (Ma)& Pole Pole A95 or Rotated to Rotated to
Q-value error latitude longitude a95 Dalziel 1992 Gondwana Reference
LAURENTIA
22. Mean pole 4
23. Mean pole 6
24. Mean pole 6
25. Mean pole 6
26. Mean pole 4
27. Mean pole 6
810*40 25”N
780*05 02”N
725i15 06”s
580*20 45”N
550+ I5 l3”N
505i I5 03”s
328”E 15”
319”E 06”
336”E 15”
305”E 8”
345”E 15”
344”E 12”
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
NR Torsvik et al., 1996
NR Torsvik et al., 1996
NR Torsvik et al., 1996
28”s. 356”E Torsvik et al., 1996
NR Torsvik et al., 1996
NR Torsvik et al., 1996
Notes: Euler poles for Rodinia (Dalziel, 1992; Torsvik et al., 1996): Congo 2.8”N, 41.3”W. - 167.6”; Rio Plata 1.9”N, 22.3”W.
- 97.7”; India 53.l”N. 145.1”E, + 167.9”; Australia 28.9”N, 126.1°E, + 132.1”; Baltica 72”N, 043”E, - 50”; Seychelles 33”N,
126”E. + 169.9” (Laurentia fixed); India 29.6”N, 36.l”E. - 56.8”; Australia 24.6”s. 60.4”W, +49.9”; Rio Plata 45.5”N. 32.2”W,
+57.5”; Antarctica 2.4”S, 327.3”E. +55.4”: Seychelles l4”N. 80”E, +2l”.
The assembly of Gondwana 800-550 Ma 229
with collisional events in the East African Orogen and suggests that either (a) the collision of
the Congo craton and Arabian-Nubian shield with East Gondwana was contemporaneous with
(caused?) rifting between East Gondwana and Laurentia or (b) that something else (fragments
of East Gondwana other than Australia/Antarctica) collided with East Africa to form the
Mozambique Belt. By all accounts, at any rate, Gondwana assembly appears to have been
complete by 0550 Ma, as discussed below.
Torsvik et al. (1996) included the data from Baltica to show that rifting of Rodinia along the
(present-day) eastern margin of Laurentia began before 580 Ma (Fig. 3). Dalziel (1992) has
suggested that the rifting in eastern Laurentia culminated in continent-continent separation
during the 550-530 Ma interval. Given that Gondwana was already assembled by then, a second
supercontinent may have existed fleetingly near the Precambrian/Cambrian boundary. Powell
(1995) has suggested the name Pannotia for the supercontinent that consisted of Laurentia
juxtaposed against a united Gondwana (Fig. 4). The available paleomagnetic data (Table 1) are
not sensitive enough to rigorously test this hypothesis although an immediate juxtaposition
between Laurentia and Gondwana near the Precambrian/Cambrian boundary has been argued
against on fauna1 grounds (Torsvik et al., 1996) and a tectonic model for the formation of the
northern Damara Belt (Hoffman, 1996). We simply note here that the existence of Pannotia is
an open question that may ultimately be resolved by more paleomagnetic, geochronologic and
geologic data from both Gondwana and Laurentia.
GONDWANA ASSEMBLY
Table 1 lists the available paleomagnetic data for Laurentia, Baltica and Gondwana from
815-515 Ma that meet the criteria set forth in Meert et al. (1995). These data were used by
Torsvik et al. (1996) to test the timing of Rodinia breakup (summarized in Fig. 3). The poles are
rotated into the Gondwana configuration of de Wit ef al. (1988) in order to gain some possible
insights into the timing of Gondwana assembly (Fig. 5). Although there is a paucity of data from
the Gondwana continents for the interval from 815-600 Ma, the available poles do not form a
coherent swathe until 550 Ma suggesting that 550Ma is the earliest age of Gondwana
formation. While a 550 Ma collision is tenable for Gondwana assembly it leaves the significance
of the 800-650 Ma East African origin unresolved. A recent paleomagnetic result from the
Mahe granites (Seychelles; Suwa et al., 1994) provides a possible link between paleomagnetic
results from East Africa and India as shown in Fig. 5. The Congo path can be traced from the
810 Ma Gagwe lavas pole to the 743 Ma Mbozi complex pole and then perhaps to the Mahe
granites pole. The Indian path tracks from the 814 Ma Harohalli pole (Dawson and Hargraves,
1994) to the Malani rhyolites pole (729 Ma; Klootwijk, 1975) and then to the 683 Ma Mahe
granites pole of Suwa et al. (1994). A tentative conclusion is that the 683 Ma Mahe pole may
represent the paleomagnetic link between India, Madagascar (and Seychelles) and Sri Lanka
with East Africa corresponding to the age of formation of the Mozambique Belt. The timing of
this event corresponds to the ages of peak metamorphism as documented by Stem er al. (1994)
for East Africa and is consistent with the petrographic and chemical characteristics of the
granites in the Seychelles (Suwa et al., 1994). The Mahe granites are dated at 683* 16 (Rb-Sr;
Yanagi et al., 1983) and exhibit incompatible trace element chemical characteristics that fall
between volcanic arc granites and within-plate granites (I-type and A-type; Suwa et al., 1994).
There are older granites in the Seychelles that exhibit I-type chemical characteristics (713 Ma)
and younger granites (570 Ma) that are strictly within-plate. Therefore it appears that the
intrusive history of the Seychelles granites is consistent with the idea that terminal continent-
230 J. G. Meert and R. Van der Voo
continent collision occurred around 683 Ma.
As previously noted the paleomagnetic data from Gondwana show a coherent swathe of poles
beginning at 550 Ma. If the breakup between the South American cratons and Laurentia in the
Rodinia continent did not take place until sometime post-580 Ma as implied by the stratigraphic
data of Williams and Hiscott (1987), then we can use the Laurentian paleomagnetic poles as a
proxy for the Amazonian and Rio Plata cratons at 580 Ma. The 580 Ma mean pole for Laurentia
is rotated to Rio Plata coordinates and is shown (pole 25) with its A95 circle dashed in Fig. 5.
While the pole falls close to the Gondwana path it is equally valid to consider that it represents
a mid-point along the path between the 709 Ma La Tinta pole (Valencio et al., 1980) and the
550-530 Ma old segment of the Gondwana path. The 547 Ma Sinyai metadolerite pole (Fig. 5;
Fig. 4. The supercontinent Pannotia. This supercontinent may have existed for a geologically brief
moment near the Precambrian/Cambrian boundary and is predicated on the belief that Gondwana assembly
was completed prior to the rift-drift transition between eastern Laurentia and the cratonic nuclei of South
America (see Dalziel, 1992 and Powell, 1995).
The assembly of Condwana 800-550 Ma 231
Meert and Van der Voo, 1996) also provides an important tie-point to the Australian poles and
is consistent with the idea of a younger collision in East Gondwana at 550 Ma. This younger
collision is represented by 550 Ma granulite formation in southern India (Unakrishan-Warrier et
al., 1995), southern Madagascar (Andriamarofahatra, 1990; Paquette et al., 1994; Kroner et al.,
1996), Sri Lanka (Kroner and Williams, 1993) and Enderby Land (Antarctica; Shiriashi et al.,
1994). There is certainly debate as to the significance of these 550 Ma ages and there have been
suggestions that they merely reflect extensional collapse of the East Africa Orogen (Windley er
al., 1994); however, combined with the observations from the paleomagnetic data it is also
reasonable to suggest that they reflect a younger continent-continent collision in that region of
Gondwana. Meert et al. (1995) suggested the name Kuunga Orogeny for this younger 550 Ma
/ f f
f I
I I I I
I 2 I
I I
f I
Gondwana Poles 8 10-5 10 Ma I
I I
I
MlN
60N
30N
ON
240E 270 E 300E 330 E 0 30E 60E 90E 120E
Fig. 5. Paleomagnetic poles for Gondwana for the interval 810-510 Ma rotated to Africa coordinates
using the euler poles of de Wit et al. (1988). The poles are numbered according to their listing in Table 1.
A polarity choice was made for the older poles to demonstrate the possibility that the East Africa Orogen
took place at around 680 Ma. The mean 580 Ma pole for Laurentia (#25, Table 1) has been rotated to
Gondwana coordinates using an euler pole at 17.9”N, 35 l”E, + 142.9” to serve as a proxy for the South
American cratonic nuclei. The path begins to show a spatial and temporal coherence for all the Gondwana
paleopoles beginning at 550 Ma (pole #3) corresponding to the timing of the latter phases of the Brasiliano
Orogeny and the Kuunga Orogeny.
232 J. G. Meert and R. Van der Voo
collision and indicated that it likely resulted from the collision of Australo-Antarctica with the
combined tectonic elements assembled earlier during the older East Africa orogeny.
CONCLUSIONS
Figure 6 summarizes the tectonic events associated with the assembly of Gondwana.
Gondwana was not fully assembled until around 530 Ma following the East African
(800-650 Ma), Brasiliano (600-530 Ma) and Kuunga (~550 Ma) orogenies. Figure 6(a) shows
the closure of the Mozambique Ocean between East Africa and elements of East Gondwana that
culminated in continent-continent collision by 650 Ma. This collision partially overlaps in time
with the rifting events in western Laurentia (Rodinia). Figure 6(b) shows the hypothesized
sequence of events taking place during the Brasiliano and Kuunga orogenies. The elements of
South America (Rio Plata and Amazonia) and Laurentia close the Adamastor Ocean and may
have resulted in the formation of the very short-lived supercontinent Pannotia. Collision of
Australo-Antarctica with the rest of Gondwana occurs at about 550 Ma and it is likely that
6(a) 800-650 Ma: East Africa Orogeny
Rodinia
6(b) 600-530: Brasiliano & Kuunga Orogenies
6(c) Cladogram of Gondwana Assembly
Fig. 6. (a) Plate cartoon showing the hypothesized geometric relationships during the closure of the
Mozambique Ocean just prior to the 680 Ma culmination of the East African Orogeny; (b) plate cartoon
showing the hypothesized geometric relationships during the final stages of Gondwana assembly
(Brasiliano and Kuunga Orogenies) 600-530 Ma; and (c) generalized cladogram of tectonic events leading
to the formation of the Gondwana supercontinent.
The assembly of Gondwana 800-550 Ma 233
Gondwana was fully assembled by 530 Ma. The model proposed here is consistent with the
available paleomagnetic and geochronologic data; however, the lack of a robust database
precludes a more detailed analysis of Gondwana assembly particularly during the 700-600 Ma
interval. The ultimate story of Gondwana assembly must await more complete paleomagnetic,
geochronologic and geologic information.
AcknowledgementsThe author wishes to thank Nick Rast for organizing a special session on supercontinental
assembly and breakup at the 1995 Southeastern section of the Geological Society of America meeting in Knoxville, TN
and subsequent organization of this special volume. The author also thanks Prodip Dutta for reviewing an early draft
of this manuscript. This work was supported by the Division of Earth Sciences National Science Foundation grants EAR
92-05 I58 and EAR95-21571.
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