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The relative disposition of continental
fragments during the dispersal phase of a supercontinent cycle can be examined
in terms of the intercontinental migration patterns of shallow marine faunas
such as brachiopods and trilobites.
Ordovician
biogeography - nacjin.jpg
The continental fragments not only have a dispersal history, they also have a history of variation in their topography (rifting, warping and tilting), and in their elevation relative to sea level. In this respect, care should be taken not to confuse transgressions of the seas due to sea level rise on a tilted surface with transgressions related to the tilting itself.
The tectonic effects of the Late
Proterozoic - Cambrian break-up of the Rodinian supercontinent can be analyzed
in terms of the relative thickness of stratal sequences deposited on the
margins of the rifted continents. Of particular interest are the elongated
aulacogens
(failed rifts) and 'bull's eye' basins of
the eastern continental margin of North America.
Net subsidence
rates during the Sauk transgression - nacsauk.jpg
Net subsidence
rates during the Tippeconoe transgression - nactipp.jpg
North American
depositional sequences according to Sloss - nacburg1.jpg
During supercontinent breakup continents get that sinking feeling because they move off the positive thermal anomaly that keeps them buoyant while they are part of a thermally insolated supercontinent. In contrast during the re-assembly phase involving ocean destruction, the topography of continents will be influenced by effects related to 1) obduction and thrust loading, and 2) subduction beneath the continental margins. Furthermore, depositional sequences may also signal a change in relative sea level as a result of changes in global sea-floor spreading rates and of changes in climate, and some cases continental transgression may reflect coeval obduction, thrusting, subduction, and eustatic rise in sea level.
Continental margin
tilting mechanisms - nacmod1.jpg
Mechanisms
for generating dynamic topography - nacburg2.jpg
North American
dynamic topography generated by slab subduction - nacburg4.jpg
The orogenic history of the North America craton subsequent to the break-up of Rodinia is therefore recorded not only in the accretion of the marginal 'geosynclines' of Appalachia and the Western Cordillera, but also in the transgressive-regressive flooding events demarcated by the Phanerozoic cover rocks of the interior cratonic parts of the continent. Sedimentary deposits laid down in a single transgressive - regressive cycle are known as depositional sequences (and subsequences). Sequences are bounded by regional unconformities and are known by name: (from earliest to latest; Roman numerals indicate subsequences): SAUK I, II, III (Cambrian); TIPPECANOE I, II (Ordovician/Silurian); KASKASIA I, II (Devonian); ABSAROKA I, II, III (Carboniferous, Pennsylvanian); ZUNI I, II, III (Jurassic); TEJAS I, II, III (Paleocene).
The Sauk and Zuni I sequences record the changes in dynamic topography resulting from supercontinent break-up, whereas the Tippecanoe, Kaskasia, Absaroka, Zuni II -III and Tejas sequences reflect events related to ocean closure and continent collision/fusion. The effect of low angle subduction beneath the Cretaceous to Miocene western continental margin of North America is particular evident in the Zuni III transgression, whereas the history of the Michigan basin includes effects related to both the opening and closing of the Iapetus ocean.
North American depositional sequences according to Sloss - nacburg1.jpg
The
Michigan Basin
Stratigraphic
columns for the Michigan basin - nacstratcol.jpg
Hisotrical
Geology - terminology
Isopach
maps for the Sauk and Tippeconoe sequences in the Michigan basin - nacmich1.jpg
Isopach
maps for the Kaskaskia sequence in the Michigan basin - nacmich2.jpg
Isopach
maps for the Absaroka and Zuni sequences in the Michigan basin - nacmich3.jpg
Isopach,
decompacted isopach and tectonic subsidence rate maps of the Middle Ordovician
of the Michigan basin - nacmichiso.jpg
Tectonic
and basement subsidence curves, Michigan Basin - nacmichcoak.jpg
Principal References:
Sloss, L.L. 1988. Tectonic evolution of the craton in Phanerozoic time. The Geology of North America, Vol D-2, Sedimentary Cover - North American Craton, p. 25-51.
Fisher et al.
1988. Michigan Basin.The Geology of North America, Vol D-2, Sedimentary
Cover - North American Craton, p. 361-382.
Burgess, P. M., Gurnis, M., and Moresi, L. 1997.
Formation of sequences in the cratonic interior of North America by interaction
between mantle, eustatic, and stratigraphic processes. BGSA, v. 109, p.
1515-1535.
Coakley, B. and Gurnis, M. 1995. Far-field tilting of Laurentia during the Ordovician and constraints on the evolution of a slab under an ancient continent. J. Geophys. Res., v. 100, 6313-6327.
Copper, P., and Jin, J. 1996. Ordovician (Llanvirn-Ashgill) rhynchonellid brachiopod biogeography. Proceedings of the 3rd International Brachiopod Congress, Sudbury, p. 123-132.
the Phanerozoic is an EON (EONOTHEM);
the Paleozoic is an ERA (ERATHEM;)
the Cambrian is a PERIOD (SYSTEM);
the Caradocian and Mohawkian are EPOCHS (SERIES)
the Blackriverian is an AGE (STAGE);
EON, ERA, PERIOD, EPOCH, and AGE are 'Geochronologic' or 'Geologic Time' units, they are subdivisions of pure time.
EONOTHEM (EON), ERATHEM (ERA), SYSTEM (PERIOD), SERIES (EPOCH), STAGE (AGE) are 'Chronostratigraphic' or 'Time stratigraphic' units, they are units of time based on the subdivision of the rock record.
'Rock stratigraphic' units include Supergroup, Group, Formation, Member, Bed, they are material rock units and have no time connotation.
'Biostratigraphic' units are units of rock defined on their fossil content without any necessary time connotation.
The Phanerozoic Eon is divided into nine periods:
Cambrian, Ordovician, Silurian; Devonian; Carboniferous; Triassic; Jurassic; Cretaceous; Tertiary = Paleogene + Neogene; Quaternary.
At the Epoch/Series and Age/Stage level of subdivision, there is considerable controversy with respect to the Ordovician. The geochronologic EPOCH divisions of the Ordovician are, for example commonly cited in the literature as being Tremadocian, Arenigian, Llanvirnian, Llandeilian, Caradocian, and Ashgillian; (or, in the case of chronostratigraphic SERIES subdivisions, as Tremadoc, Arenig. etc), but in other cases, as below, these divisions are now considered to represent STAGES/AGES. Similarly, although the North American Ages/Stages of the Ordovician are commonly shown as Canadian, Whiterockian, Chazyan, Blackriverian, Rocklandian, Kirkfieldian, Shermanian, Edenian, Maysvillian, Richmondian; the Whiterock(ian) is sometimes shown as a SERIES, and the Rocklandian, Kirkfieldian, Shermanian are sometimes incorporated into a single Trenton or Chatfield STAGE.
CORRELATION CHART FOR THE PALEOZOIC (adapted from Sloss, 1997)
System Series Stage Ma Subsequences Pleistocene 2 - 0 Tertiary Neogene Pliocene 5.1 - 2 ___________________________ Miocene 24.6 - 5.1 Tejas III Paleogene Oligocene 38 - 24.6 29-------------------------- Eocene 54.9 - 38 39----Tejas II-------------- Paleocene 65 - 54.9 60----Tejas I--------------- ---------------------------------------------------------- Cretaceous Upper Maastrichtian 73 - 65 Campanian 83 - 73 Santonian 87.5 - 83 Zuni III Coniacian 88.5 - 87.5 Turonian 91 - 88.5 ____________________________ Cenomanian 97.5 - 91 96-------------------------- Lower Albian 113 - 97.5 Aptian 119 - 113 Barremian 125 - 119 Zuni II Hauterivian 131 - 125 Valangian 138 - 131 134------------------------- Berrisian 144 - 138 ---------------------------------------------------------- Jurassic Upper Portlandian 50 - 144 Kimmeridgian 156 - 150 _____________________________ Oxfordian 163 - 156 Zuni I Middle Callovian 169 - 163 Bathonian 175 - 169 _____________________________ Bajocian 181 - 175 Lower Aalenian 188 - 181 186------------------------- Toarcian 194 - 188 Pleinsbachian 200 - 194 Sinemurian 206 - 200 Hettangian 213 - 206 ---------------------------------------------------------- Triassic Upper Rhaetian 219 - 213 Absaroka III Norian 225 - 219 _____________________________ Carnian 231 - 225 Middle Ladinian 238 - 231 _____________________________ Anisian 243 - 238 Lower Scythian 245 - 243 245------------------------- ---------------------------------------------------------- Permian Ochoa Tartarian 253 - 245 Guadelupe Leonard Kazanian 258 - 253 Absaroka II Kungurian 263 - 258 Artinskian 268 - 263 Wolfcamp Sakmarian 286 - 268 268------------------------- ----------------------------------------------------------- Pennsylvanian Virgin Stephanian 296 - 286 Missouri Des Moines D C Westphalian 320 - 296 Absaroka I B Atoka A C Morrow Namurian B ------------------------------------------------------- 333 - 320 330------------------------ Mississipian Chester A Visean 352 - 333 Valmayer Kinderhook Tournaisian 360 - 352 Kaskaskia II ---------------------------------------------------------- Devonian Upper Famennian 367 - 360 362------------------------- _____________________________ Frasnian 374 - 367 Middle Givetian 380 - 374 Eifelian 387 - 380 Kaskaskia I _____________________________ Emsian 394 - 387 Lower Siegenian 401 - 394 Gedinnian 408 - 401 401------------------------- --------------------------------------------------------- Silurian Upper Pridoli 414 - 408 _____________________________ Ludlow 421 - 414 Tippecanoe II Wenlock 428 - 421 Lower Llandovery 438 - 428 ----------------------------------------------------------- Epoch Substage Graptolite zone Ordovician_Upper Ashgillian 448 - 438 438------------------------- Middle Caradocian 458 - 448 Onnian P. linearis Actonian Marsbrookian D. clingani Longvillian Soudleyan Harnagian C. multidens Costonian Llandeilian 468 - 458 Tippecanoe I Late N. gracilis Early G. teretiusc. Llanvirnian 478 - 468 Late D. muchisoni ____________________________ Early D. artus (bifidus) Lower Arenigian <483 - 478 Fennian D. hirundo I. gibberulus Whitlandian D. nitidus Moridunian D. deflexus P. approximatus Tremadocian 505 - <483 483-------------------------- Late Early R. Flabeliforme ----------------------------------------------------------- Cambrian Upper Trempealeauian 515 - 505 Sauk III Franconian ____________________________ Dresbachian 523 - 515 515-------------------------- ______________Middle________ 548 - 523 Sauk II ______________Lower_________ 590 - 548 548-------------------------- ----------------------------------------------------------- Precambrian Ediacaran - 590 Sauk I 600--------------------------
References- isotopic dating
Landing, Ed, Bowring, S.A., et al., 1997, U-Pb zircon date from Avalonian
Cape Breton Island and geochronologic calibration of the Early Ordovician,
CJES, 34 5, p.724-730.
COMMENT: Uppermost Tremadoc
K-bentonite from the Chesley Drive Group on McLeod Brook (Hunnebergian
Stage), eastern Cape Breton Island is 483+1; age of the Tremadoc - Arenig
series boundary is younger than 483 Ma. Base of T. Approximatus is the
base of the Arenig. Compston's 482 Ma age of the Llyfnant Flags is revised
to 476 (Roddick and Bevier, 1995) and dates the D. deflexus zone above
T. approximatus. Arenig-Llanvirn estimated as c. 475-466 or 472
Tucker, R.D. and McKerrow, W.S. 1995. Early Paleozoic chronology: a review
in light of new U-Pb zircon ages from Newfoundland and Britain, CJES, 32,
4, 368-379.
COMMENT: max base of Cambrian
= 551; basal Llandeilo ash = 460; basal Caradoc = 456+2; latest Llandovery
= 430+2.4; latest Ludlow = 420+4; base of Ordovician =495; base of Silurian
= 443; base mid Devonian = 391; base of devonian estimated to be 417
Compston, W. and Williams, I.S., Ion probe ages for the British Ordovician
and Silurian statotypes, 1992, Global perspectives on Ordovician Geology,
Webby and Laurie, eds., Balkema, Rotterdam p[ 59-67.
COMMENT: Early Arenig, Llyfnant
Flags - 471+3; Early Llanvirn, Llanrin volcanics - (465.7); Late Llanvirn,
Serw Fm - 462+3 (464.6); Mid-Caradoc, Longvillian, 451+2 (456+1.5) Mid-Caradoc,
Longvillian, Pont-y-ceunant Ash 448+4 (457.2); Ashgill Rawtheyan, Hartfell
Shale - (445.7); Early Llandovery, Rhuddainian, Birkhill Shale 430+3 (438.7);
Ludlow, Gorstian, 419.6+2.8; values in brackets and for the early Llanvirn
and Ashgill are those of Tucker et al. 1990.
Most Recent References
2000 GSA Pgrm w. Abst 2000
A-9
Session 6 Clastic SedimentsI: Provenance, Tectonics
and diagenesis of Siliciclastic rocks
Goodge, J.W.
et al., Age and provenance of the Beardmore Group, Antarctica: constraints
on Rodinia Supercontinent Breakup.
Resume: Detrital
zircons in siliciclastic rocks of the Neoproterozoic (inoard proximal)
to early Paleozoic (outboard, distal , latest Early to Middle Cambrian)
Beardmore Group are Sources for the rift/passive margin inboard assemblage
is 2800 and 1900-1400 Ma; for the outboard first-cycle sediments the sources
are arcs with ages of 580-550 Ma and Grenville age basement , 1100-940
Ma, and a ~825 Ma magmatic centre. Youngest grains in the outboard are
526-518. "The presence of ~1400 Ma components in both assemblages cannot
be easily explained by Antarctic or Australian sources, but may signify
connection to Proterozoic granite provinces in Laurentia."
A-313 Session 140 Superplume
events in Earth History: Causes and effects I
A-317 Session 142 Proterozoic
Tectonic evolution of western Laurentia: continental accretion to breakup
of Rodinia I
A-455 Session 203 Precambrian
extravaganza: Supercontinents
1999 GSA Pgrm w. Abst 1999
A-318 Session 138 Role of supercontinents
in Earth History
A-428 Session 186 Igneous, metamorphic,
and geochronologic perspectives on continental assembly and breakup
Clark, D. J., Hensen, B. J., Kinny, P. D., 2000. Geochronological constraints
for a two-stage history of the Albany-Fraser Orogen, Western Australia.
Precambrian Research, 102, 3-4, p. 155-183.
AB: Based
on structural, petrographic and geochronological work (SHRIMP zircon, monazite
and rutile), the Mesoproterozoic Albany-Fraser Orogeny is divided into
two discrete thermo-tectonic stages, between c. 1345
and 1260 Ma (Stage I) and c. 1214 and 1140
Ma (Stage II). The existence of a two-stage history is confirmed
by the discovery of 1321+/-24 Ma detrital zircons and 1154+/-15 Ma
metamorphic rutiles in metasedimentary rocks from Mount Ragged. The detrital
zircons demonstrate that the Mount Ragged metasedimentary rocks unconformably
overly, and were derived from, Stage I basement. Metamorphic rutile formed
as a consequence of overthrusting by high-grade early-Stage II rocks along
an inferred NE-SW striking structure (the Rodona Fault). This interpretation
is supported by zircon geochronology, which demonstrates that granulite
facies metamorphism on the northwestern side of the structure predates
that on the southeastern side by approximately 100 Ma. Rocks
to the northwest record a low-grade imprint relating to the younger (Stage
II) event.
The two-stage thermo-tectonic history of the Albany-Fraser Orogen correlates
with adjacent Grenville-age orogenic belts in Australia and East Antarctica,
implying that Mesoproterozoic Australia assembled in two stages subsequent
to the amalgamation of the North Australian and West Australian cratons.
Initial collision between the combined West Australian
- North Australian craton and the South Australian-East Antarctic continent
at c. 1300 Ma was followed by intracratonic reactivation affecting basement
and cover at c. 1200 Ma. Two comparable and contemporaneous compressional
orogenies controlled the formation of the Kibaran Belt in Africa and the
Grenville Belt in Canada, suggesting that tectonic
events in Mesoproterozoic Australia follow a similar pattern to that recognised
for Rodinia amalgamation world-wide.
References arranged chronologically
Texeira, W. et al., 1989 A review of the geochronology of the Amazonian
craton: tectonic implications: Prec. Res., 42, 213-227.
McMenamin, M.S. and McMenamin, D.L.S., 1990 The emergence of animals: the
Cambrian breakthrough: Columbia Univ. Press, New York,217p.
Hoffman, P.F., 1991 Did the breakout of Laurentia turn Gondwanaland inside-out:
Science, 25, June, 1409
Moores, E.M., 1991 Southwest U.S. - East Antarctic (SWEAT) connection:
a hypothesis. Geology, 19, 5, 425-428
Murphy, J.B. and Nance, R.D., 1991 Supercontinent model for the contrasting
character of Late Proterozoic orogenic belts: Geology, 19, 5, 469-472.
Dalziel, I.W.D., 1991 Pacific margins of Laurentia and east Antarctica
- Australia as a conjugate rift pair: evidence and implications for an
Eocambrian supercontinent: Geology, 19,598-601.
Boucout, A. J. discuss. Moores, E.M. and Dalziel, I.W.D. reply, 1992 Southwest
U.S. - East Antratic (SWEAT) connection: a hypothesis and Pacific margins
of Laurentia and Antarctica - Australia as a conjugate rift pair: evidence
and implications for an Eocambrian supercontinent: Geology, 20, 1, 87-88.
Comment: were not connected during the Cambrian
Dalziel, I.W.D., 1992 On the organization of American Plates in the Neoproterozoic
and the breakout of Laurentia: GSA_Today, 2, 11, 237-241.
Davidson, G., 1992 Piecing together the Pacific: New Scientist,January,
25-29.
Ross, G.M. Parrish, R.R., and Winston, D., 1992 Provenance and U-Pb geochronology
of the Mesoproterozoic Belt Supergroup (northwestern United States): implications
for age of deposition and pre-Panthalassa plate reconstructions: EPSL,
113, 1/2, 57-76.
Stern, R.J. et al. discuss. Dalziel, I.W.D. reply, 1992 Pacific margins
of Laurentia and East Antarctica - Australia as a conjugate rift pair:
evidence and implications for an Eocambrian supercontinent: Geology, 20,
2, 190-191.
Stump, E., 1992 The Ross orogen of the Transantractic Mountains in light
of the Laurentia-Gondwana split: GSA_Today, 2, 2, 25-31.
Trench, A. and Torsvik, T.H., 1992 The closure of the Iapetus Ocean and
Tornquist Sea: new palaeomagnetic constraints: JGS, 149, 6, 867-870. Comment:
Early Wenlock Mendip data = 12 +/-5 South in Mid-Silurian; Brit and Scand
sectors of Iapetus were closed by the early Wenlock; Acadian Deformation
post-dates initial docking of Eastern Avalonia and Laurentia; previous
paleomag data for Tornquist to remain open in the Mid-Silurian is removed
Salda, L.H.D. Dalziel, I.W.D., et al., 1992 Did the Taconic Appalachians
continue into southern South America?: Geology, 20, 12, 1059-1062.
Young, G.M., 1992 Late Proterozoic stratigraphy and the Canada - Australia
connection: Geology, 20,215-218.
Brookfield, M.E., 1993 Neoproterozic - Laurentia fit: Geology, 21, 8, 683.
Comment: compares major glacial sequences on each margin
Powell, et al., 1993 Paleomagnetic constraints on timing of the Neoproterozic
breakup of Rodinia and the Cambrian formation of Gondwana: Geology, 21,
10, 889-892. Comment: East Gondwana and Laurentia separation after 725
Ma following formation of the Pacific ocean; low latitude Rapitan and Sturtian
glaciations occurred during the rifting; Laurentia moved to high latitudes
by 580 Ma, east Gondwana stayed at low latitudesThe younger Marinoan, Ice
Brook and Varangian, caused formation of the eastern margin of Laurentia
and rejuvenation of its western margin. Gondwana was not fully assembled
until the end of the Neoproterozoic, possibly as lat as Mid-Cambrian
Borg, and DePaolo, D.J., 1994 Laurentia, Australia, and Antarctica as a
Late Proterozoic supercontinent: constraints from isotopic mapping: Geology,
22, 4, 307-310.
Dalziel, Dalla Salda, L.H., and Gahagan, L.M., 1994 Paleozoic Laurentia-Gondwana
interaction and the origin of the Appalachian - Andean mountain system:
BGSA, 106, 2, 243-252.
Dalziel, I Knoll, A., and Moores, E., 1994 Late Precambrian tectonics and
the Dawn of the Phanerozoic: GSA Today, Jan,8-9.
Dalziel, I.W.D., 1994 Precambrian Scotland as a Laurentia - Gondwana link:
origin and significance of cratonic promontories: Geology, 22, 7, 589-592.
Gurnis, M. and Torsvik, T.H., 1994 Rapid drift of large continents during
the late Precambrian and Paleozoic: paleomagnetic constraints and dynamic
models: Geology, 22, 11, 1023-1026. Comment: burst in latitudinal velocity
followed the breakup of Rodinia. In early Paleozoic Avalonia was attached
to to the northwest margin of Gondwana. Avalonia rifted off Gondwana during
early Ordovician time and merged with Baltica by Late Ordovician. Batlica
Avalonia collided with Laurentia my Middle Silurian time 425 ma to form
Laurasia. Later collision with Gondwana and the European massifs formed
Pangea by Permian time.
Meert, J.G. Hargraves, R.B. et al., 1994 Paleomagnetic and 40Ar/39Ar studies
of Late Kibaran intrusives in Burundi, East Africa: implciations for Late
Proterozic Supercontinents: Jour. Geol., 102,621-637. Comment: xeroxed;
Kibaran peaked at 1300 (1400-1200 Ma; intruded by ultramafic/mafic and
felsic plutons between 1275 and 1220 Ma; 950 Ma thermal event; Rodinia
was not fully formed at 1200 Ma. Mid-Proterozoic plate movements leading
to Grenville aged collison c. 1100-1000 Ma and the assembly of Rodinia
Marshall, J.E.A., 1994 The Falkland Islands: a key element in Gondwana
paleoeography: Tectonics, 13, 2, 499-514.
Idnurm, M. and Giddings, J.W., 1995 Paleoproterozoic - Neoproterozoic North
america - Australia link: new evidence from paleomagnetism: Geology, 23,
2, 149-152.
Li, et al., 1995 South China in Rodinia: part of the missing link between
Australia - East Antarctica and Laurentia: Geology, 23, 5, 407-410.
Torsvik, T.H. Tait, J., Moralev, V.M., McKerrow, W.S., Sturt, B.A., and
Roberts, D., 1995 Ordovician palaeogeography of Siberia and adjacent continents:
JGS, 152, 2, 279-288.
Young, G.M., 1995 Are Neoproterozoic glacial deposits preserved on the
margins of Laurentia related to the fragmentation of two supercontinents?:
Geology, 23, 2, 153-156.
Li, Z.-X. Zhang, L., and Powell, C.M., 1995 South China in Rodinia: part
of the missing link between Australia - East Antarctica and Laurentia?:
Geology, 23,407-410.
Young, G.M., 1995 Are Neoproterozoic glacial deposits preserved on the
margins of Laurentia related to the fragmentation of two supercontinents?:
Geology, 23,.
Dalziel, I.W.D. and McMenamin discuss. Young, G.M. reply, 1995 Are Neoproterozoic
glacial deposits preserved on the margins of Laurentia related to the fragmentation
of two supercontinents: Geology, 23, 10, 959-960. Comment: two supercontinents
1) post Grenville to opening of the Pacific c. 725, and 2) post-725 involving
amalgamation of Gondwana
Ortega-Gutierrez, F. et al., 1995 Oxaquia, a Proterozoic microcontinent
accreted to North America during the late Paleozoic: Geology, 23, 12, 1127-1130.
Park, J.K. Buchan, K.L., and Harlan, S.S., 1995 A proposed giant radiating
dyke swarm fragmented by the separation of Laurentia and Australia based
on paleomagnetism of ca 780 Ma mafic intrusions in western North America:
EPSL, 132,129-139.
Daliel, I.W.D. and Dalla Salda, L.H. discuss Torsvik, T.H., Tait, J., Moralev,
V.M., McKerrow, W.S.,Sturt, B.A, and Roberts, D., reply, 1996 Ordovician
palaeogeography of Siberia and adjacent continents: JGS, 153,329-330.
Dalziel, I.W. and Dalla Salda, L.H. and Astini, R.A., Benedetto, J.L.,
and Vaccari, N.E. reply, 1996 The early Paleozoic evolution of the Argentine
Precordillera as a Laurentian rifted, drifted, and collided terrane: a
geodynamic model: discussion: BGSA, 108, 3, 372-375.
Dalziel, I.W.D. and Dalla Salda, L.H. Torsvik, T.H. et al. reply, 1996
Discussion on Ordovician palaeogeography of Siberia and adjacent continents:
JGS, 153, 2, 329-330.
Jin, J, 1996 Ordovician (Llanvirn-Ashgill) rhynchonellid brachiopod biogeography:
Proceedings of the 3rd International Brachiopod Congress, Sudbury, A.A.
Balkema, Rotterdam,123-131.
Conti, C.M. et al., 1996 Paleomagnetic evidence of an early Paleozoic rotated
terrane in northwest Argentina: a clue for Gondwana-Laurentia interaction?:
Geology, 24, 10, 953-956.
Hoffman, P.F., 1996 No SWEAT: Pan-African Damara orogen (Namibia) as an
unstable triple point, with implications for Rodinia: GSA Ann. Meet. Abst.
and Programs, Denver, 28, 7, 60. Comment: closure of the Mozambique and
Brasilide oceans commensurate with the break up of 1.05-.75 Rodinia. The
southern Mozambique suture either extends into eastern Queen Maud Land
via Sri Lanka, southern India and Madagascar or is accomodated by a trench-trench
transform linking the Mozambique and Brasilide oceans between the Congo
and Kalahari cratons, involving dextral transform through the Damara and
Zambesi belts. However, structures associated with the T-junction in Namibia
where the Damara belt meets the Brasilides (Gariep and Kaoko belts) imply
that both belts were obliquely sinistral. Thrust related sinistral-oblique
stretching lineations are observed on the lithospheric footwall of each
belt. Folds and thrusts wrap around the southwest corner fo the congo craton
into the mouth of the Damara belt from the north, consisant with anticlockwise
material flow in the wake of an unstable northward migrating triple junction
which is a corollary of sinistral obliquity in the Damara and Basilide
belts. Therefore western Queen Maude Land and the Kalahari craton were
not tied to the rest of East Antarctica-australia until closure of the
Mozambique ocean. Therefore Grenville could have continued into the Namaque-Natal
belt with the Kalahara and west Queen Maude land along the Argentine pre-
cordillera conjugate to southern Laurentia. The purported extension of
the Grenville Front between the Coats Land nunataks and the Shackelton
range would no longer be a valid reason for positioning East Antarctica
- Australia with respect to Laurentia, because one or both of the former
areas would have been unconnected to Antarctica - Australia.
Unrug, R., 1997 Rodinia to Gondwana: the geodynamic
map of Gondwana Supercontinent Assembly: GSA Today, 7, 1, 1-5.
Walter, M.R. and Veevers, J.J., 1997 Australian Neoproterozoic
palaeogeography, tectonics, and supercontinental connections: AGSO Journal
Australian Geology and Geophysics, 17, 1, 73-92.
Lieberman, B.S., 1997 Early Cambrian paleogeography and tectonic history:
a biogeographic approach: Geology, 25, 11, 1039-1042.
Dalziel, I.W.D., 1997 OVERVIEW: Neoproterozoic - Paleozoic geogrphy and
tectonics : review, hypothesis, environmental speculation: BGSA, 109, 1,
16-42.
Hanson, R.E. et al., 1998 U-Pb zircon age for the Umkondo dolerites, eastern
Zimbabwe: 1.1 Ga large igneous province in southern Africa - East Antarctica
and possible Rodinia correlations: Geology, 26, 12, 1143-1146.
Arlo B. Weil, Rob Van der Voo, Conall Mac Niocaill, Joseph G. Meert, 1998
The Proterozoic supercontinent Rodinia: paleomagnetically derived reconstructions
for 1100 to 800 Ma: EPSL, 154, 1-2, 13-24.
Karlstrom, K.E. Harlan, S.S., Williams, M.L., McLelland, J., Geissman,
J.W., and Ahall, K.I., 1999 Refining Rodinia: geologic evidence for the
Australia - Western connection in the Proterozoic: GSA Today, 9,1-7.
Waggoner, B., 1999 Biogeographic analyses of the Ediacara biota: a conflict
with paleotectonic reconstructions: Paleobiology, 25,440-458.
Anon, 2000 1999 GSA Pgrm w. Abst A-318 Session 138 Role of supercontinents
in Earth History A-428 Session 186 Igneous, metamorphic, and geochronologic
perspectives on continental assembly and breakup:,.
Anon, 2000 2000 GSA Pgrm w. Abst A-9 Session 6 Clastic SedimentsI: Provenance,
Tectonics and diagenesis of Siliciclastic rocks A-313 Session 140 Superplume
events in Earth History: Causes and effects I A-317 Session 142 Proterozoic
Tectonic evolution of western Laurentia: continental accretion to breakup
of Rodinia I A-455 Session 203 Precambrian extravaganza: Supercontinents:,.
Sears, J.W. and Price, R.A., 2000 New look at the Siberian connection:
no SWEAT: Geology, 28,423-426.
Burrett C. and Berry, R., 2000 Protoerozoic Australia - Western United
States (AUSWUS) fit between Laurentia and Australia: Geology, 28, 2, 103-106.
Fitzsimons, I.C.W., 2000 Grenville-age naswement provinces in East Antarctica:
evidence for three separate collisional orogens: Geology, 28, 10, 879-882.
Murphy, J.B. Strachan, R.A., Nance, R.D., Parker, K.D., and Fowler, M.B.,
2000 Proto-Avalonia: a 1.2 - 1.0 Ga tectonothermal event and constraints
for the evolution of Rodinia: Geology, 28, 12, 1071-1074.
Preiss, W.V., 2000 The Adelaide Geosyncline of South Australia and its
significance in Neoproterozoic continental reconstruction: Precambrian
Res., 100, 1-3, 21-63.
Wingate, M.T.D. and Giddings, J.W., 2000 Age and palaeomagnetism of the
Mundine Well dyke swarm, Western Australia: implications for an Australia-Laurentia
connection at 755 Ma: In Walter, M.R., ed, Neoproterozoic of Australia.
Precambrian Res., 100, 1-3, 335-357.
Piper, J.D.A., 2000 The Neoproterozoic supercontinent: Rodinia or Palaeopangaea?:
EPSL, 176, 1, 131-146.
Dynamic topography
References arranged chronologically
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Cross, T.A. and Pilger, X.H. , 1982 Controls of subduction geometry , location
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America, Vol D-2, Sedimentary cover - North American Craton 361-382
Milici, R.C. and de Witt, W., 1988 The Appalachian Basin, Chapter 15: The
Geology of North America, Vol D-2, Sedimentary cover - North American Craton
427-469
Sloss, L.L. , 1988 Tectonic evolution of the craton in Phanerozoic time:
The Geology of North America, Vol D-2, Sedimentary cover - North American
Craton 25-51
Sloss, L.L. , 1988 Conclusions, Chapter 17: The Geology of North America,
Vol D-2, Sedimentary cover - North American Craton 493-496
Mitrovica, J.X. Beaumont, C. and Jarvis, G.T., 1989 Tilting of continental
interiors by the dynamical effects of subduction: Tectonics, 8, 5, 1079-1094
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Beresi, M.S. , 1992 Ordovician cycles and sea-level fluctuation in the
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perspectives on Ordovician Geology, Balkema, Rotterdam 337-323
Cooper, R.A. , 1992 A relative timescale for the Early Ordovician dervied
from depositional rates of graptolite shales: in Webby and Laurie, eds.,
Global perspectives on Ordovician Geology, Balkema, Rotterdam 3-21
Nielsen, A. T. , 1992 Ecostratigraphy and the recognition of Arenigian
(Early Ordovician) sea-level changes: in Webby and Laurie, eds., Global
perspectives on Ordovician Geology, Balkema, Rotterdam 355-379
Ross, J.R.P. , 1992 Ordovician sea-level fluctuations: in Webby and Laurie,
eds., Global perspectives on Ordovician Geology, Balkema, Rotterdam 327-335
Taylor, J.F. , 1992 The Stonhenge transgression: a rapid submergence of
the central Appalachian platform in the Early Ordovician: in Webby and
Laurie, eds., Global perspectives on Ordovician Geology, Balkema, Rotterdam
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Early Ordovician sea level events in Australia and Scandinavia: in Webby
and Laurie, eds., Global perspectives on Ordovician Geology, Balkema, Rotterdam
381-394
Gurnis, M. , 1992 Long term controls on eustatic and epeirogenic motions
by mantle convection: GSA Today, 7, 2, 141-157
Runkel, A.C. , 1994 Deposition of the uppermost Cambrian (Croixan) Jordan
Sandstone and the nature of the Cambrian-Ordovician boundary in the Upper
Mississippi Valley: BGSA, 106, 4, 492-506
Wise, D.U. discuss. Moores, E.M. reply, 1994 Neoproterozic oceanic crustal
thinning, emergence of continents, and origin of the Phanerozoic ecosystem:
a model: Geology, 22, 1, 87-88
Coakley, B and Gurnis, M., 1995 Far-field tilting of Laurentia during the
Ordovician and constraints on the evolution of a slab under an ancient
continent: Jour. Geoph. Res., 100, B4, 6313-6327
Burgess, P.M. Gurnis, M., and Moresi, L., 1997 Formation of sequences in
the cratonic interior of North America by interaction between mantle, eustatic,
and stratigraphic processes: BGSA, 109, 12, 1515-1535.
Pascal Lecroart, Anny Cazenave, Yanick Ricard, Catherine Thoraval,Douglas
G. Pyle 1997 Along-axis dynamic topography constrained by major-element
chemistry. EPSL, 149, 1-4, 49-56. Comment: Variations in thickness and
density of both the crust and the associated upper mantle have been derived
from a compilation of zero-age major-element composition along the Mid-Atlantic
Ridge, the East Pacific Rise and the Southeast Indian Ridge. Assuming isostatic
compensation, the axial depth computed from major-element data correctly
agrees with observed axial depth. Discrepancies are essentially located
near hotspots such as Iceland and Azores. The residual topography, expressed
as the difference between observed and compensated axial depth has a root-mean-square
of 426 m along the three spreading axes, which is below the resolution
power of the method. This insignificant topography, which is assumed to
contain the dynamic surface topography associated with mantle convection,
bears an important constraint on the relative variations of the dynamic
topography predicted by models of mantle circulation.
Structural Provinces of North America.
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