Carboniferous_Permian_paleogeography_of the assembly of pangaea.pdf

Wong, Th. E. (Ed.): Proceedings of the XVth International Congress on Carboniferous and Permian
Stratigraphy. Utrecht, the Netherlands, 10–16 August 2003.
Royal Netherlands Academy of Arts and Sciences
Carboniferous–Permian paleogeography of the assembly of Pangaea
R.C. Blakey
Department of Geology, Northern Arizona University, Box 4099, Flagstaff, Arizona 86011, USA;
e-mail: ronald.blakey@nau.edu
Abstract
The supercontinent Pangaea dominated all aspects of Earth history for nearly 150 million years. The events in both
western and eastern Pangaea document complex Wilson cycles with the opening and closing of oceans and terrane
and continent collisions. The assembly of Pangaea is part of a supercontinent cycle that began in Late Proterozoic
with the break-up of the previous supercontinent Rodinia. Much of the detail of earlier events is obscured by
later culminating orogenies. Despite such difficulties, reasonably detailed paleogeographic reconstructions can be
made of the complex events surrounding the assembly of Pangaea and both global and regional North Atlantic
reconstructions are presented here.
The tectonic events that culminated with the Carboniferous–Permian assembly of Pangaea can be synthesized
into three general sequences. (1) In the Late Proterozoic, North America, Baltica and Siberia rifted from the
supercontinent Rodinia and drifted northward leaving Gondwana straddling the South Pole. The Iapetus Ocean
separated North America, Baltica and Gondwana. (2) During the Ordovician, Silurian and Devonian, North
America, Baltica, Avalonia, and peri-Siberian terranes converged to form Laurussia and the Caledonian orogeny.
A series of peri-Gondwanan terranes rifted from Gondwana and drifted northward to collide with Laurussia.
These events left Laurussia facing a rapidly approaching Gondwana across the narrowing Rheic and paleo-Tethys
Oceans. (3) Beginning in the Mississippian and continuing into the Pennsylvanian and Permian, Gondwana and
Laurussia collided obliquely to close the Rheic Ocean and form Pangaea. Siberia and Kazakhstan closed from
the east to generate the Ural orogeny. A series of peri-Gondwanan terranes docked during early phases of the
Marathon, Ouachita, Alleghanian, and Variscan orogenies, either as separate terranes or on the leading edge
of Gondwana. Pangaea was amalgamated during the final collision of Gondwana and Laurasia, but continuing
transpressional and transform tectonics adjusted paleogeography until rifting began in the Triassic.
Farther to the east in the Tethyan region, broadly similar events occurred during the assembly of central and
SE Asia, although the three general sequences occurred later than the above events. (1) The Sino-SE Asia blocks
rifted from eastern Gondwana during the middle Paleozoic. The greater Kazakhstan and Sakmarian arcs bordered
southern Siberia and eastern Baltica. (2) During the Carboniferous–Permian, Siberia, Kazakhstan, and Baltica
collided and North China docked with Mongolia and Siberia. The Cimmerian blocks rifted from Gondwana.
(3) The Cimmerian blocks and remaining Sino-SE Asia blocks docked with southern Asia during the Early
Mesozoic. As eastern Pangaea was finally assembled, western Pangaea began its initial rifting.
The mountains at the Pangaean suture must have rivalled the modern Alpine–Himalayan system and formed
barriers to floral and faunal elements of the Late Paleozoic and Early Mesozoic. Sediment derived from these
mountains filled coeval depositional systems on and along northern Pangaea. Epicontinental seas retreated from
the elevated Pangaean landmass resulting in diminished shallow marine environments – a possible early event that
may have contributed to the great Permo-Triassic extinction event. The structural grain of Pangaean events still
dominates portions of eastern North America, northwestern Europe, and central Eurasia today.
Keywords: Carboniferous–Permian, Earth history, paleogeography, Pangaea, plate tectonics.
R.C. Blakey 443

Introduction
Objectives, methods, and limitations
Syntheses of geologically complex regions over vast
amounts of time are challenging endeavours. Such
studies must attempt to honour diverse geological
and geophysical data and incorporate a wide range
of complex and commonly differing interpretations of
these data. In this study I present a global synthesis
of the tectonic assembly of Pangaea from Cambrian
through Jurassic with emphasis on the Late Paleozoic;
more detailed maps show the complex Carboniferous–
Permian paleogeography of what is today the North
Atlantic region. The maps presented here are part of
an ongoing project to represent Earth paleogeography
at various scales and over various regions through-
out deep geologic time. Regional and global data
are used to create detailed and visually realistic pa-
leogeographic maps that document the assembly of
the supercontinent Pangaea. The maps were prepared
from published tectonic, geophysical, stratigraphic,
sedimentologic, and paleontologic data that I assem-
bled by time slice and plotted on base maps. Major
plate configurations are modified from Ziegler (1988,
1990), Sengor & Natal’in (1996), Yin & Nie (1996),
Scotese (1998), Matte (2002) and Stampfli et al.
(2002a, 2002b). From this database, geologic and
geographic elements (mountains, cratonic lowlands,
trenches, arcs, etc.) were located and a rough paleo-
geographic map was produced. General shorelines for
North America are from Cook & Bally (1975) and
for Europe are from Ziegler (1988, 1990). Finally,
the detailed paleogeography was painted over the base
using the program Adobe Photoshop® with a vari-
ety of techniques. Emphasis was placed on construct-
ing textures and colours as they might have appeared
from space during the time interval depicted. Most
of the complex geomorphic elements were cloned
from shaded digital elevation maps from various ter-
ranes around the present Earth. The original maps
were prepared in colour but are presented here in
greyscale; coloured versions are available on the web
at <http://jan.ucc.nau.edu/∼rcb7>.
The accuracy, completeness, and detail presented
on the various maps are affected by a number of fac-
tors including the accuracy, completeness, and dis-
tribution of data, the interpretation and correlation
of data, and my compromises made on conflicting
interpretations published in the literature; when at-
tempting this reconstruction, several major decisions
must be made with respect to the origin of several
important and controversial terranes and groups of
terranes. Plotting and graphical errors can occur in
the published literature and in my assembly of data
on base maps. Usually the tighter the time interval
between maps, the more obvious these kinds of mis-
takes become; in some cases, various elements are
adjusted or smoothed to present a more realistic tran-
sition from map to map: I attempt to track all ma-
jor terranes and tectonic elements through a series
of closely spaced paleotectonic and paleogeographic
time slices. The time slices were originally assembled
at 5–10 m.y. intervals and then presented at the in-
tervals shown. The time intervals are correlated to the
International Stratigraphic Chart 2004 and published
by Gradstein et al. (2004). An important aspect con-
cerning pre-Jurassic plate reconstructions is that all
ocean crust from this time span has been destroyed or
accreted and smeared as ophiolite packages; all data
are solely derived from the continents.
The emphasis of this paper is the presentation of
the maps; because of space limitations, text is kept
to a minimum. Figures with extended figure captions
present most of the information in this paper.
Global tectonic events related to Pangaea
assembly
Overview of Pangaea
Pangaea was assembled from several larger continents
and a number of micro-continents, arcs, and inter-
vening oceanic plates (Fig. 1). Assembly began in the
Cambrian or Ordovician and continued into the Per-
mian for western Pangaea and into the Early Mesozoic
for eastern Pangaea. Most of the points of assembly
(collisions) were the sites of orogenic events; the in-
vestigation and interpretation of these mountain belts
provides much of the database for the construction of
the maps. By the Early Mesozoic, most of the Earth’s
continental crust was part of Pangaea. However, as
eastern Pangaea was finally assembled, western Pan-
gaea began to rift and the Atlantic Ocean was born.
The tectonic anatomy of Pangaea assembly is pre-
sented in Fig. 2. The origin of the approximately 20
elements is as follows: (1) North America, Baltica,
Siberia and Gondwana are the four major continents
following the Late Proterozoic break-up of the pre-
vious supercontinent Rodinia (Torsvik et al., 1996).
(2) Gondwana, the largest of the continents, con-
tinued to shed continental fragments throughout the
Paleozoic; these fragments, generally referred to as
peri-Gondwanan terranes, drifted northward to col-
lide with evolving configurations of North America,
Baltica and Siberia (which themselves were collid-
ing in the Middle and Late Paleozoic). The western
peri-Gondwanan terranes are linked by the distinc-
444 Carboniferous–Permian paleogeography of the assembly of Pangaea

Fig. 1. Mollewide globe showing paleogeography after assembly of western Pangaea (300 Ma Late Pennsylvanian). The Ural–Variscan–
Appalachian, Ouachita–Marathon mountain chain marks the areas of continental collision. The blocks that will comprise central and SE Asia
are drifting across the Paleotethys ocean and will assemble eastern Pangaea in the Mesozoic. Key to abbreviations used on all paleogeographic
and paleotectonic maps – blocks, terranes, and continents: AFR – Africa; Arm – Armoricia; Arm/B – Armoricia/Bohemia; Aus/A – Austro-
Alpine; BAL – Baltica; boh – Bohemia; can – Cantabria; car – Carolina; Cho – Chortis; CHU – Chukotka; CIM 1,2 – Cimmeria (1st and
2nd elements); Eav – East Avalonia (Avalonia ss. of some authors); EHT – European Hunic terrane; fla – Florida; GON – Gondwana; GUR
– Guerrero Superterrane; HUN – Hun superterrane; Ibe – Iberia; KAZ – Kazakhstan; MON – Mongolia; MEG Meguma; mes – Mesita;
NAM – North America (Laurentia); NCH – North China; NZD – New Zeeland; OAX – Oaxaca Superterrane; SAM – South America;
SCH – South China; SIM – Simbasu (Indochina); swp – SW Portugal; Tac/P – Taconia/Piedmont; Wav – West Avalonia; WRG – Wrangellia
superterrane; Yuc – Yucatan. Sutures and orogenies: AcO – Acadian orogeny; AcS – Acadian suture; AlO – Alleghanian orogeny; AnO –
Antler orogeny; ArM – Ancestral Rocky Mountains; CaO – Caledonian orogeny; CaS – Caledonian suture; ElO – Ellesmerian orogeny; ElS –
Ellesmerian suture; eVaS – early Variscan sutures; FiO – Finnmark orogeny; FiS – Finnmark sutures; GrO – Grampian orogeny; lVAS – late
Variscan/Alleghanian sutures; MaO – Marathon orogeny; McO – McClintock orogeny; OMS – Ouachita/Marathon suture; OuO – Ouachita
orogeny; ShO – Shelvian orogeny; TaO – Taconic orogeny; TaS – Taconic suture; VaO – Variscan orogeny. See text for sources of data.
Fig. 2. Diagram showing terranes, continents, and blocks before Pangaean assembly. Arrows show general relative directions and ages of
convergence between various elements and locations of paleo oceans. This figure summarizes the major events discussed in this paper.
R.C. Blakey 445

Table 1. Ages of orogenies and orogenic phases related to the assembly of western Pangaea.
Shaded blocks show ages from Ziegler (1990), McKerrow et al. (2000), and Hatcher (2002). Bars show ages from other sources keyed by
lower case letters a (Trettin, 1989), b (Chaloupsk’y, 1988), c (Roberts, 1988), d (McKerrow, 1988), e (Hall and Roberts, 1988). Timescale
and absolute ages from Gladstein and Ogg (2004); ages show lower boundaries of systems, series, and stages. Boxes show area and ages of
Caledonian orogeny as defined by McKerrow et al. (2000); Orogenic mega-cycles from Ziegler (1990). Abbreviations under Caledonian: G
– Greenland, S – Scandinavia, MC – Maritime Canada.

Fig. 3. Global paleogeography of Cambrian–Devonian and the pre-assembly of Pangaea. A – Late Cambrian (500 Ma); three major continents,
North America, Baltica, and Siberia rift from Gondwana opening early Paleozoic oceans; most or all peri-Gondwanan terranes are still
attached to Gondwana. The Kipchak arc extends east from Baltica. B – Early to Middle Ordovician (470 Ma); the Early Paleozoic oceans
are near their maximum extent and their demise is marked by a series of arcs and subduction zones along North America, Siberia, and
Baltica; arc collisions/collapse against these continents generate early orogenic phases (see Table 1) of Caledonian orogeny (McKerrow et
al., 2000). Several of the peri-Gondwanan terranes have rifted from Gondwana and begin to drift northward. C – Early Silurian (430 Ma);
North America, Baltica, and East Avalonia converge obliquely and diachronously to close the Iapetus Ocean and Tornquists Sea and generate
the Caledonian orogeny. To the east, the Kipchak arc begins a series of infoldings to form the nucleus of Kazakhstan and North and South
China rift from Gondwana. West Avalonia approaches the central coast of eastern North America and Iberia, Armoricia, Bohemia, and
Austro-Alpine terranes (grouped as Hun superterrane of Stampfli et al., 2002a) close on southern Europe. The Antler arc approaches western
North America. In the Arctic region, Chukotia, a peri-Siberian terrane approaches collision with northern Canada. D – Early Devonian
(400 Ma); as North America and Baltica collide, plate patterns reorganize with subduction zones nearly ringing the new Laurussia (Old Red)
continent (Ziegler, 1990). The Kazakhstan and Sakmarian arcs lay to the east, the Ligerian to the south, the Acadian to the SE, and the Antler
to the west. The Mongol arc bordered Siberia to the north. The second wave of peri-Gondwanan terranes (Hun superterrane of Stampfli
et al., 2002a) was drawn towards these arcs and their collisions throughout the Devonian and Early Mississippian built much of central and
southern Europe and the eastern US. McKerrow et al. (2000) considered these events to be post-Acadian/Caledonian orogeny; Ziegler (1990)
considered these events pre-Hercynian. See text for additional sources of data.
tive Late Proterozoic Cadomian basement, which sug-
gests close tectonic affinities before Paleozoic dispersal
(Murphy et al., 2000). Most of SE Asia also comprises
former peri-Gondwanan terranes including the Cim-
meria blocks, the last pieces added to the Pangaean
puzzle (Sengor & Natal’in, 1996). The geometric con-
figuration of the peri-Gondwanan terranes that mi-
grated across Paleozoic and Early Mesozoic oceans is
the subject of much disagreement. (3) Mongolia and
Kazakhstan evolved as large, complex, long-lived arcs
built partially on Proterozoic microcontinents; their
evolution involved accretion and collision tectonics
(Sengor & Natal’in, 1996).
The tectonic and geologic history of Pangaea is
organized into four broad events: (1) break-up of
the previous supercontinent Rodinia, (2) assembly of
Laurussia and Laurasia, (3) assembly of western Pan-
gaea, (4) assembly of eastern Pangaea and coeval ini-
tial break-up of western Pangaea.
Break-up of Rodinia: Late Precambrian–Ordovician
Following the break-up of Rodinia (Unrug, 1997),
three major continental blocks, North America
(NAM), Baltica (BAL) and Siberia (SIB), rifted from
Gondwana (Fig. 3A,B) and moved northward to-
wards the equator (Torsvik et al., 1996, and references
therein). The Iapetus Ocean (pre-Atlantic ocean ter-
minology of Van der Voo, 1993) wrapped around
eastern, southern, and northern NAM (present coor-
dinates) separating it from the other major continental
masses (Fig. 4A,B). Several blocks separated from
NAM including Precordillera and Taconia-Piedmont
(Astini et al., 1995; Waldron & van Staal, 2001) and
an uncertain number of small fragments and island
arcs were imbedded within the Iapetus (e.g., Barr et
al., 2002). Patterns of mid-ocean ridges were com-
plex though details of ridge location and geometry are
unknown.
R.C. Blakey 447

(E)
Fig. 4. Details of Caledonian events in present North Atlantic region. A – Late Cambrian (500 Ma); A series of west-facing arcs approach
the passive eastern and northern margins (present coordinates) of North America. The Iapetus Ocean nears its maximum width. B – Early

Fig. 4. (Continued): to Middle Ordovician (470 Ma); arc-continent collisions in both North America and Baltica begin the early phases of
Caledonian orogeny. Northern Iapetus Ocean begins to close as subduction zones jump outboard of accreted arcs eliminating ocean crust
on both sides. All elements of Caledonian orogeny (ss. McKerrow et al., 2000) are clearly visible: North America, Baltica, East Avalonia,
Iapetus Ocean, Tornquists Sea. C – Early Silurian (430 Ma); East Avalonia slides into Baltica to form Shelvian phase of Caledonian orogeny
and together, the two elements close on North America; the Ligerian arc fringes East Avalonia to the south. Chukotia is drawn into arcs
along northern Canada and the Antler arc approaches the passive margin of western North America. In my reconstructions, West Avalonia
is separate from East Avalonia (cf. Ziegler, 1990) although several reconstructions show them as continuous plate margin (cf. Torsvik et
al., 1996). I favour the former, as the main Acadian orogeny is much younger (Frasnian–Famennian) than the main Caledonian orogeny
(Emsian–Eifelian; see Table 1). Of course, strongly oblique collision of a single plate could probably produce the same results. D – Early
Devonian (410 Ma); main phase of Caledonian orogeny. Baltica and East Avalonia collide with North America; West Avalonia trails on
separate plate with Meguma. Gondwana and peri-Gondwanan terranes appear at SE margin across Theic and Rheic Oceans. E – Detailed
paleogeography of D. This time is during Devonian low stand so only peri-continental seas border the main continental areas of Laurussia.
Key to symbols and colors used on North Atlantic maps: light grey – North America, Siberia, and Baltica; medium grey – terranes derived
from above continents; medium dark grey – Gondwana and peri-Gondwanan terranes; dark grey – active orogenic areas; medium grey lines
– mid-ocean ridges; thin black lines – transform faults; heavy black lines – subduction zones; adjacent small circles – arc volcanoes (location
diagrammatic); curved lines at top of each map – horizon of globe. State, province, and country outlines on smaller terranes for reference
only; shapes of terranes very uncertain until amalgamation and completion of orogeny. See text for additional sources of data.
Fig. 5. Global paleogeography of Late Devonian–Mississippian and the closing of Rheic–Theic Oceans. A – Late Devonian (370 Ma);
Hun superterrane (Iberia, Armoricia/Bohemia, Austro-Alpine terranes) collide with southern Europe; West Avalonia collides with North
America. The narrow Rheic–Theic Oceans separate the main Gondwanan landmass from Laurussia. The China blocks move northward
across Paleotethys Ocean and Siberia approaches northern Baltica and Kazakhstan begins to slide in the apex between them. The Sakmarian
arc lies east and north of Baltica. The Antler arc begins to collide with western North America. B – Early Mississippian (Visean; 340 Ma);
early phases of Variscan–Alleghanian orogeny as parts of Africa and arcs bordering southern Gondwanan terranes intercept North America
(Ouachita orogeny). Kazakhstan collapses against the closing Siberia and Baltica and North China closes against southern Kazakhstan. The
Cimmerian terranes begin to rift from Gondwana, continuing a familiar pattern of rifting peri-Gondwanan terranes. The Antler arc has
accreted to western North America and subduction jumps to the west. See text for sources of data.
R.C. Blakey 449

(E)
Fig. 6. Details of early phases of Variscan–Alleghanian orogeny, present North Atlantic region. A – Late Devonian (370 Ma); with West
Avalonia and the Hun superterrane accreted to eastern North America and southern Europe, the Rheic–Theic Oceans close as Gondwana
approaches. Gondwana is preceded by a series of peri-Gondwanan terranes that make the first contact with North America. As the Antler arc

Fig. 7. Global spherical views during Early Permian (280 Ma).
Views are perpendicular to horizontal equator through centre of
each globe. Upper: Western Hemisphere showing assembly of west-
ern Pangaea. Lower: Eastern Hemisphere showing North China
docked below Mongolia with South China, Indochina, and Cim-
merian terranes below. The Paleotethys Ocean protrudes into west-
ern Pangaea. See text for sources of data.
Convergence: Early and Middle Paleozoic
After reaching maximum dispersal in the Late Cam-
brian or Early Ordovician, subduction zones began
to close intervening oceans and the continents be-
gan a long, complex period of convergence (Torsvik
et al., 1996; Mac Niocaill et al., 1997; van Staal et
al., 1998; Stampfli et al., 2002a). Ordovician colli-
sions of Taconia-Piedmont with NAM and several arc
terranes with BAL generated the Taconic and Fin-
mark orogenies respectively (Figs 3C, 4C). During the
Silurian and Devonian, NAM, BAL, Avalonia (a peri-
Gondwanan terrane), and Chukotka (a peri-Siberian
terrane) converged to form Laurussia and generate
the culmination of the Caledonian, Ellsmerian (Mc-
Cann, 2000), and Acadian orogenies (Figs 3D, 4D,E).
I follow the formal definitions of the Caledonian
orogeny and its phases as proposed by McKerrow
et al. (2000); see Table 1. Meanwhile, a series of
peri-Gondwanan terranes rifted from Gondwana and
drifted northward across the waning eastern Rheic
Ocean to collide with Laurussia (Fig. 3D); these
included Armorica-Bohemia, Iberia, West Avalonia,
Meguma, and Austo-Alpine among others (Ziegler,
1990). Stampfli et al. (2002a) grouped these ter-
ranes into the Hun superterrane. This phase of ter-
rane accretion closed the southern Iapetus Ocean
and eastern Rheic Ocean and left Laurussia facing a
rapidly approaching Gondwana across the narrowing
western Rheic-Theic Ocean (Figs 5A,B, 6A,B). Fig-
ures 6A,B,C suggest that the peri-Gondwana terranes,
Carolina, Yucatan, and Chortis were separated from
the leading edge of Gondwana as it closed on Laurus-
sia. These terranes may have collided before the main
Gondwana collision and may have been the cause of
several local Late Devonian to Early Mississippian
orogenic events (Hatcher, 2002). Mississippian sea-
ways were kept open from E–W between southern
NAM and Southern Europe and Africa (Fig. 6B,E),
a geometry supported by paleontological evidence
(Allen & Dineley, 1988; Laveine et al., 2000).
Contrasting models by Dalziel et al. (1994), Scotese
(1998) and Keppie & Ramos (1999) presented differ-
ent versions of Middle to Late Paleozoic collisional
events. The most significant differences from mod-
els presented here are (1) collision between Laurasia
and Gondwana beginning in the Middle to Late De-
vonian, (2) Early Carboniferous separation, and (3) fi-
nal Late Carboniferous closure. A closed ocean in the
Late Devonian would have ended marine corridors
and E–W marine faunal migration before the Car-
boniferous while promoting floral mixing before the
Late Carboniferous. These events would seem to con-
flict with the paleontologic evidence presented above.
Fig. 6. (Continued): collides with western North America, subduction jumps west of the accreted terrane. B – Early Mississippian (350 Ma);
the Hun superterrane collided with a strong oblique component and eastern portions moved west along transform faults bringing Cantabria
(most of Iberia) to the south of Armoricia (Stampfli et al., 2002a). The collision of Carolina may be responsible for the preliminary and
Lackawanna phases of the Alleghanian orogeny (cf. Hatcher, 2002). C – Late Mississippian (325 Ma); the Reguibat promontory of Africa
collides with EC North America beginning the ‘zipper tectonics’ that will close the Rheic–Theic Oceans and generate the Alleghanian orogeny
(Hatcher, 2002). The large arrows show the relative plate movements and demonstrate why some areas of collision were nearly head-on while
others were oblique to transform. The arcs bordering Yucatan and Oaxacan collide with southern North America to begin the Ouachita
orogeny. D – Early Pennsylvanian (315 Ma); the Rheic and Theic Oceans are closed and the main phase of the Alleghanian and Variscan oro-
genies is underway. The Ouachita orogeny propagates into inland North America with the Ancestral Rocky Mountains. The McCloud arc
builds on western North America (Miller et al., 1992; Saleeby, 1992). See Fig. 1 for global paleogeography at 300 Ma. E – Detailed paleo-
geography of B. Although siliciclastic sedimentation was prevalent near orogenic belts, great carbonate platforms dominated epicontinental
seas of North America, Europe, and North Africa. See text for additional sources of data.
R.C. Blakey 451

(C)
Fig. 8. Details of assembled western Pangaea, present North Atlantic region. A – Late Pennsylvanian (300 Ma); Mountains of the Variscan–
Alleghanian–Ouachita–Marathon orogeny separate Laurasia from Gondwana. The white areas below the southern US may represent remnant
oceans that formed gaps where continental masses never collided. The McCloud arc became dismembered during the complex truncation
of SW North America. B – Early Permian (275 Ma); active compressional tectonics was probably over along the continental suture between
Laurasia and Gondwana. A new tectonic regime was building in the form of the Cordilleran arc along the margin of western North America.
C – Detailed paleogeography of A. Towards the end of the Carboniferous (Late Pennsylvanian, Missourian high-stand of Heckel, 1995),
western Pangaea was assembled, although compressional tectonics would continue for another 50 m.y. between Laurussia and Gondwana.
Note the paired foreland basins opposite the region of most perpendicular collision; the mountains were most likely highest in that region,
also. This map represents paleogeography during a high stand so some of the coal-bearing regions such as the coal measures of Midwestern
US are flooded by marine incursions; at lower sea levels, these areas would be vast coal swamps and fluvial plains. See text for sources of data.

Fig. 9. Permo-Triassic (250 Ma) reconstruction of western Pangaea in the present North Atlantic region. All of the tectonic elements that have
been tracked in this paper are shown. Compare with Fig. 2. Heavy white line marks Caledonian suture between Baltica and North America
and ensuing SE boundary with accreted peri-Gondwanan terranes. Dark grey heavy line marks NE margin of Gondwana. The accreted
peri-Gondwanan terranes lie between these two lines. See text for sources of data.
Until important details such as these become resolved,
paleogeographic reconstructions will remain in flux!
Assembly of Western Pangaea: Carboniferous–Permian
Beginning in the Mississippian and continuing into
the Pennsylvanian and Permian, Gondwana and Lau-
russia collided obliquely to close the Rheic and Pa-
leotethys Oceans and form Pangaea (Ziegler, 1990).
The complex collision probably featured several in-
tervening terranes (Fig. 6C,D) and involved strongly
oblique and rotational convergence that distributed
collisional forces differently along the orogenic front in
zipper-fashion (Hatcher, 2002). The peri-Gondwanan
terranes undoubtedly affected the outcome of parts
of the collisional orogeny and resulted in major local
modifications. Some docked during early phases of the
Marathon, Ouachita, Alleghanian, and Variscan oro-
genies, probably as separate terranes off the leading
edge of Gondwana. Others, especially those towards
the southern edge of the orogen, may have never suf-
fered major collision, but rather collided obliquely or
not at all with any solid continental terrane (Keller &
Cebull, 1973; cf. Royden, 1993); for example, Chor-
tis, and possibly Oaxaca ended along the free face
south of southern NAM (Fig. 6D) and became in-
corporated in paleo-Pacific subduction zones where
they would be later affected by Mesozoic tectonics
(Dickinson and Lawton, 2001). Yucatan and Florida
closed obliquely on southern NAM and were buffered
from solid collisions by promontories that took col-
lision head-on. Terranes such as Carolina (see Hi-
bbard, 2000 for review of controversy surrounding
its history) and Meguma were involved in areas of
direct continental collision and their docking histo-
ries were obscured by major Alleghanian events. Fol-
lowing the final continental collision, the resulting
Variscan–Appalachian mountain chain formed a con-
tinuous continental divide from Mexico on the SW to
Southern Europe to the NE (Figs 7, 8A,B,C). Mean-
while, Siberia and Kazakhstan closed from the east to
collide with Baltica and generate the Ural orogeny and
form Laurasia (Sengor & Natal’in, 1996). Western
Pangaea was amalgamated during the final collision
R.C. Blakey 453

of Gondwana and Laurasia in the Pennsylvanian and
Permian, but continued transpressional and transform
tectonics adjusted paleogeography (Hatcher, 2002)
until rifting began in the Triassic. Figure 9 shows the
final assembled elements of western Pangaea.
Assembly of Eastern Pangaea: Late Permian–Jurassic
In the Tethyan region, broadly similar events oc-
curred during the assembly of central and SE Asia,
although the three general sequences occurred later
than the above events. (1) The Sino-SE Asia blocks
rifted from eastern Gondwana during the middle Pa-
leozoic to form the Proto-Tethys Ocean. The greater
Kazakhstan and Sakmarian arcs bordered southern
Siberia and eastern Baltica (Fig. 5). (2) During the
Carboniferous–Permian, Siberia, Kazakhstan, and
Baltica collided (Fig. 7) and North China docked
with Mongolia and Siberia (Fig. 10A); South China
docked soon afterwards (Yin & Nie, 1996), although
Laveine et al. (2000) pointed out that North and
South China had land contact by the middle of the
Carboniferous to allow floral elements to spread be-
tween the two regions. 3) Final assembly of eastern
Pangaea involved the complicated events surrounding
the Cimmerian plates (Sengor & Natal’in, 1996). The
Cimmerian blocks rifted from Gondwana to form the
Paleo-Tethys and Tethys Oceans in the Late Carbonif-
erous (Fig. 1). These blocks and remaining Sino-SE
Asia blocks docked with southern Asia during pro-
tracted orogenies in the Triassic and Jurassic (Sengor
& Natal’in, 1996). As eastern Pangaea was finally
assembled, western Pangaea began its initial rifting
(Fig. 10B,C).
Summary: significance of Pangaean events
The dominance that Pangaea and the events that
formed it had on geologic history is truly astonish-
ing. This dominance is seen not only near orogenic
events but in distal regions, also. The base of the
Absaroka Sequence in North America (Sloss, 1988)
occurs at the Mississippian–Pennsylvanian boundary
and marks a profound change in continent-wide sedi-
mentation from carbonate below to siliciclastic above.
This is coincident with early phases of the Alleghanian
and Ouachita orogenies (see Table 1). Also coincident
is a marked increase in formation and preservation
of continental depositional systems on a global basis,
not only adjacent to orogenic highlands. The great
influx of aeolian depositional systems into the US
Western Interior began in the Pennsylvanian (Blakey
et al., 1988) and the Permo-Triassic redbeds domi-
nate on a global basis. Pennsylvanian–Lower Permian
Fig. 10. Global paleogeography of Permian and Triassic emphasiz-
ing assembly of SE Asia. A – Late Permian (260 Ma); the terranes
of southern and SE Asia drift northward separating the Paleotethys
Ocean to the north from the Tethys Ocean to the south; mean-
while North China closes on Mongolia. Glaciers still persist at the
South Pole. B – Early to Middle Triassic (240 Ma); the Asian ter-
ranes continue northward; major orogeny in China resulted from
collision between North and South China blocks (Yin & Shangyou,
1996). Pangaea also moves northward; perhaps a reason that South
Pole glaciers dissipate. The Guerrero and Wrangellia superterranes
approach western North America. C – Late Triassic (220 Ma);
the southern Asian terranes collapse against central Asia and the
China blocks generating the Cimmerian orogeny (Sengor & Na-
tal’in, 1996). Lakes mark rifting between North America and Africa
as western Pangaea begins its breakup; this before the final assembly
of eastern Pangaea. See text for additional sources of data.
deposition is perhaps more cyclic than any other sim-
ilar span of geologic time (e.g., Heckel, 1995, 2001).
These perturbations in the geologic record are di-
rectly related to the dominance Pangaea and Pan-
gaean mountains had on global climate (including
glaciation), tectonism, sediment supply, and eustacy.
The sedimentation patterns, tectonic aspects of the
supercontinent cycle, climate, and eustacy weighed
heavily on biologic patterns as well. As the Paleo-
zoic drew to a close, low sea levels, increased clas-
tic detritus, reduced epicontinental seas and shallow
shelves, and climate stress combined to contribute to-

wards the largest extinction in Phanerozoic history
(Erwin, 1993). Important economic products include
hydrocarbons, coal, evaporite, and base metal deposits
(Chenoweth, 1989; Shelton, 1989). And last but not
least, the structural and topographic grain of signif-
icant parts of the Earth’s surface directly reflect the
remains of the greatest chains of mountains the world
may have ever seen – the results of continental sutur-
ing that built the supercontinent Pangaea.
Acknowledgements
Rich Lane invited me to present this paper at the
Carboniferous–Permian Congress in Utrecht and en-
couraged me to prepare a paper for the conference vol-
ume. Chris Scotese has provided support and encour-
agement for my paleogeographic reconstructions. Phil
Heckel provided details for Middle Pennsylvanian pa-
leogeography. Tom Ligon of ARC Science provided fi-
nancial support for earlier versions of the global maps.
The manuscript benefited from reviews by Charles
Henderson and Guang Shi.
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