Click here to go to 'Figures/Overheads' section.

Click here to return to course outline.

Geology of the North American Craton during the Phanerozoic

    The Late Proterozoic/Cambrian witnessed the disintegration of the supercontinent Rodinia into at least six fragments: Laurentia, Gondwana, Avalonia, Baltica, Kazakhstan, and Siberia. During the early Paleozoic these continental fragments were dispersed and re-organized, but following the closure of the Iapetus, Tornquist (North German-Polish), Rheic, Uralic, and other oceans, Laurentia eventually re-united with Avalonia, Gondwanaland, and Baltica-Eurasia to form the Permo-Triassic supercontinent known as Pangea.
    Rodinia: Hoffman - nacrod1.jpg
     Rodinia: Dalziel - nacrod2.jpg
     Rodinia: Young 1- rodyng1.jpg
     Rodinia: Young 2 - rodyng2.jpg
     Rodinia: Karlstrom 1 - rodkarl1.jpg
     Rodinia: Karlstrom 2
     Rodinia: Karlstrom 2 text
     Rodinia: Karlstrom 2A
     Rodinia: Karlstrom 2B
     Rodinia: Karlstrom 2C
     Rodinia: Piper - rodpiper2.jpg

    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.

Historical Geology  (revision) :

    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.

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
                Leonard         Kazanian                258 - 253                       Absaroka II
                                Kungurian               263 - 258
                                Artinskian              268 - 263
                Wolfcamp        Sakmarian               286 - 268               268-------------------------
Pennsylvanian   Virgin
                                Stephanian              296 - 286
                Des Moines               D       
                                Westphalian             320 - 296                       Absaroka I
                Morrow          Namurian B
------------------------------------------------------- 333 - 320               330------------------------
Mississipian    Chester                 A                       
                                Visean                  352 - 333
                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
                                Marsbrookian D. clingani
                                Harnagian    C. multidens
                  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--------------------------
                                Early        R. Flabeliforme
Cambrian           Upper        Trempealeauian          515 - 505                               Sauk III
____________________________    Dresbachian             523 - 515               515--------------------------
______________Middle________                            548 - 523                               Sauk II
______________Lower_________                            590 - 548               548--------------------------
Precambrian                     Ediacaran                   - 590                               Sauk I

    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
           Coney, P.J. and Reynolds, S.J. , 1977 Cordilleran Benioff Zones. Nature 270, 403-406
           Cross, T.A. and Pilger, X.H. , 1982 Controls of subduction geometry , location of magmatic arcs, and tectonics of arc and back arc regions. Geol. Soc. America Bull. v. 93, p. 545-52
           Fisher, J.H. et al., 1988 Michigan basin, Chapter 13: The Geology of North 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
           Mueller, S. and Phillips, R.J., 1991 On the initiation of subduction: Jour. Geoph. Res, 96, B1, 651-665
           Beresi, M.S. , 1992 Ordovician cycles and sea-level fluctuation in the Precordillera terrane, western Argentine: in Webby and Laurie, eds., Global 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 409-417
           Nicoll, R.S. et al., 1992 Preliminary correlation of latest Cambrian to 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.


Click here to return to beginning.

Click here to return to course outline.

Click here to return to W.R. Church's page.