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The Gulf of Mexico and Canada Basin: Genetic Siblings
on Either Side of North America
E.R. Lundin, Statoil ASA, Research Center, Arkitekt Ebbels vei 10, 7053 Trondheim, Norway, erlun@statoil.com; and A.G. Doré,
Statoil (UK) Ltd., One Kingdom Street, London W2 6BD, UK, agdo@statoil.com
ABSTRACT
The Gulf of Mexico and Canada Basin
are small oceans located in back-arc set-
tings of the Paleo-Pacific Ocean, at the
northern and southern tip of the North
American craton. Both are pronounced
rotational, pie-shaped basins, with their
distal ends bounded by major transforms,
and both opened by ~70° counter-clock-
wise rotation of micro-continents away
from the craton. While they formed syn-
chronously with elements of the Central
and North Atlantic, their oceanic crust
never connected with that of the Atlantic.
Both oceans were periodically confined,
with important implications for the paleo-
environment and petroleum system. Their
North American affinity resulted in a
number of intriguing similarities, such as
timing and magnitude of main sediment
influx. We argue for a genetic relation-
ship between the geometry and kinemat-
ics of these pie-shaped oceans, their
proneness to confinement, and their back-
arc setting. In contrast to common back-
arc basins, the Gulf of Mexico and
Canada Basin had spreading ridges ori-
ented nearly orthogonally to the Paleo-
Pacific subduction direction. This distinc-
tive high-angle back-arc development
may be due to “Wilson Cycle” reactiva-
tion of orogenic belts intersecting the
Paleo-Pacific margin, and/or to interac-
tion between descending slabs beneath
adjacent cratonic masses, and may apply
to other examples worldwide, such as the
South China Sea.
INTRODUCTION
Back-arc extension occurs adjacent to
subduction boundaries and is manifested
as small, contained areas of seafloor spread-
ing. Back-arc basins are particularly com-
mon around the Pacific Rim but are by no
means unique to that area. Their formation
is thought to relate to the motion and
GSA Today, v. 27, no. 1, doi: 10.1130/GSATG274A.1
4 GSA Today | January 2017
geometry of the descending subduction uplifted Colorado Plateau (e.g., Galloway
slab. Mechanisms whereby extensional et al., 2000; Dixon et al., 2008).
forces are communicated to the overrid-
ing plate are still under discussion (e.g., Differences also exist—in particular
Heuret and Lallemand, 2005; Stern and their paleo-latitudes during opening.
Dickinson, 2010) and include relative The Gulf of Mexico opened between the
backward motion of the upper plate ver- Middle Jurassic and earliest Cretaceous
sus the subducting slab, pull (rollback) and was located at a subtropical latitude,
driven by the negative buoyancy of the whereas the Canada Basin opened between
subducting lithosphere, and dynamic Early and Late Cretaceous and was located
mantle flow. close to 75° N. This difference is reflected
by the presence of evaporites and carbon-
While it is usually implicit in such mod- ates in the Gulf of Mexico area, in con-
els that the basin axes run parallel to the trast to siliciclastics in the Canada Basin
subduction boundary, it is becoming evi- (e.g., Shimeld et al., 2016). Another differ-
dent from recent studies (e.g., Stern and ence is the orientation of these oceans,
Dickinson, 2010) that basins in back-arc with the Gulf of Mexico’s rift tip located
settings can also open orthogonally or at a toward the Atlantic and the Canada Basin’s
high angle to subduction zones. We argue toward the Pacific.
that this geometry constitutes a new class
of basin that forms at the intersection of In all aspects, the Gulf of Mexico is the
major continental masses along subduction far better understood of the two basins,
margins, and that the Gulf of Mexico and due to greater ease of access for data
Canada Basin are important examples acquisition and its long and intensive his-
bordering the North American continent. tory of petroleum exploration.
We also show that these confined basins
form major sediment sinks that have GULF OF MEXICO OPENING
resulted in large hydrocarbon resources
and may have significantly affected global Gulf of Mexico rifting started approxi-
paleoclimate. mately in the Norian (228.4–209.5 Ma),
marked by poorly dated red beds and vol-
The Gulf of Mexico and Canada Basin canics of the Eagle Mills Formation (Moy
(Fig. 1) are bordered by rift shoulders and and Traverse, 1986), approximately syn-
underlain by oceanic crust and/or exhumed chronous with rifting along the Central
mantle, and contain substantial sedimen- Atlantic margin along the U.S. East Coast
tary fill, predominantly Cenozoic in age. (Olsen et al., 1996).
Neither ocean has well-defined magnetic
isochrons, but their ages can be deduced Modern interpretations of the continent-
from other geologic constraints. Both ocean boundary (COB) in the Gulf of
oceans re-opened Late Paleozoic orogens, Mexico range between two end-members.
the Carboniferous-Permian Ouachita- A “wide ocean” interpretation places
Marathon orogen and the Carboniferous COBs along the major (~200–300 nT)
Innuitian orogen, respectively. Both oceans Houston, Florida, and Campeche mag-
also opened by high-angle rotation during netic anomalies (Imbert and Philippe,
the Mesozoic. Both oceans hosted major 2005), assumed by analogy with the
Cenozoic river deltas, with a fill strongly Central Atlantic East Coast Magnetic
influenced by erosion of the Paleogene Anomaly (ECMA) to represent a magma-
Laramide orogen and subsequently of the rich margin (Holbrook et al., 1994; Imbert
and Philippe, 2005) (Fig. 2). The alterna-
tive “narrower ocean” interpretation places