The Gulf of Mexico and Canada Basin: Genetic Siblings on Either Side of North America
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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, [email protected]; and A.G. Doré, Statoil (UK) Ltd., One Kingdom Street, London W2 6BD, UK, [email protected] ABSTRACT geometry of the descending subduction uplifted Colorado Plateau (e.g., Galloway The Gulf of Mexico and Canada Basin slab. Mechanisms whereby extensional et al., 2000; Dixon et al., 2008). are small oceans located in back-arc set- forces are communicated to the overrid- Differences also exist—in particular tings of the Paleo-Pacific Ocean, at the ing plate are still under discussion (e.g., their paleo-latitudes during opening. northern and southern tip of the North Heuret and Lallemand, 2005; Stern and The Gulf of Mexico opened between the American craton. Both are pronounced Dickinson, 2010) and include relative Middle Jurassic and earliest Cretaceous rotational, pie-shaped basins, with their backward motion of the upper plate ver- and was located at a subtropical latitude, distal ends bounded by major transforms, sus the subducting slab, pull (rollback) whereas the Canada Basin opened between and both opened by ~70° counter-clock- driven by the negative buoyancy of the Early and Late Cretaceous and was located wise rotation of micro-continents away subducting lithosphere, and dynamic close to 75° N. This difference is reflected from the craton. While they formed syn- mantle f low. by the presence of evaporites and carbon- chronously with elements of the Central While it is usually implicit in such mod- ates in the Gulf of Mexico area, in con- and North Atlantic, their oceanic crust els that the basin axes run parallel to the trast to siliciclastics in the Canada Basin never connected with that of the Atlantic. subduction boundary, it is becoming evi- (e.g., Shimeld et al., 2016). Another differ- Both oceans were periodically confined, dent from recent studies (e.g., Stern and ence is the orientation of these oceans, with important implications for the paleo- Dickinson, 2010) that basins in back-arc with the Gulf of Mexico’s rift tip located environment and petroleum system. Their settings can also open orthogonally or at a toward the Atlantic and the Canada Basin’s North American affinity resulted in a high angle to subduction zones. We argue toward the Pacific. number of intriguing similarities, such as that this geometry constitutes a new class In all aspects, the Gulf of Mexico is the timing and magnitude of main sediment of basin that forms at the intersection of far better understood of the two basins, influx. We argue for a genetic relation- major continental masses along subduction due to greater ease of access for data ship between the geometry and kinemat- margins, and that the Gulf of Mexico and acquisition and its long and intensive his- ics of these pie-shaped oceans, their Canada Basin are important examples tory of petroleum exploration. proneness to confinement, and their back- bordering the North American continent. arc setting. In contrast to common back- We also show that these confined basins GULF OF MEXICO OPENING arc basins, the Gulf of Mexico and form major sediment sinks that have Gulf of Mexico rifting started approxi- Canada Basin had spreading ridges ori- resulted in large hydrocarbon resources mately in the Norian (228.4–209.5 Ma), ented nearly orthogonally to the Paleo- and may have significantly affected global marked by poorly dated red beds and vol- Pacific subduction direction. This distinc- paleoclimate. canics of the Eagle Mills Formation (Moy tive high-angle back-arc development The Gulf of Mexico and Canada Basin and Traverse, 1986), approximately syn- may be due to “Wilson Cycle” reactiva- (Fig. 1) are bordered by rift shoulders and chronous with rifting along the Central tion of orogenic belts intersecting the underlain by oceanic crust and/or exhumed Atlantic margin along the U.S. East Coast Paleo-Pacific margin, and/or to interac- mantle, and contain substantial sedimen- (Olsen et al., 1996). tion between descending slabs beneath tary fill, predominantly Cenozoic in age. Modern interpretations of the continent- adjacent cratonic masses, and may apply Neither ocean has well-defined magnetic ocean boundary (COB) in the Gulf of to other examples worldwide, such as the isochrons, but their ages can be deduced Mexico range between two end-members. South China Sea. from other geologic constraints. Both A “wide ocean” interpretation places oceans re-opened Late Paleozoic orogens, COBs along the major (~200–300 nT) INTRODUCTION the Carboniferous-Permian Ouachita- Houston, Florida, and Campeche mag- Back-arc extension occurs adjacent to Marathon orogen and the Carboniferous netic anomalies (Imbert and Philippe, subduction boundaries and is manifested Innuitian orogen, respectively. Both oceans 2005), assumed by analogy with the as small, contained areas of seafloor spread- also opened by high-angle rotation during Central Atlantic East Coast Magnetic ing. Back-arc basins are particularly com- the Mesozoic. Both oceans hosted major Anomaly (ECMA) to represent a magma- mon around the Pacific Rim but are by no Cenozoic river deltas, with a fill strongly rich margin (Holbrook et al., 1994; Imbert means unique to that area. Their formation influenced by erosion of the Paleogene and Philippe, 2005) (Fig. 2). The alterna- is thought to relate to the motion and Laramide orogen and subsequently of the tive “narrower ocean” interpretation places GSA Today, v. 27, no. 1, doi: 10.1130/GSATG274A.1 4 GSA Today | January 2017 Phase 1 (Fig. 3A): Magma-rich break-up, governed by separation of Gondwanaland and Laurentia, marked by the large posi- tive magnetic anomalies and seaward- dipping reflectors (SDRs), followed by a gradual transition to normal oceanic crust. During this phase, Yucatan was CB MPB EB attached to, and moving with, the rest of Gondwanaland, and the Gulf of Mexico opening was only weakly rotational with BB the Yucatan block sliding along the proto- Florida Escarpment and proto-Tehuantepec transform. The fit between the Houston NEA LS and Campeche magnetic anomalies, by comparison with the Atlantic ECMA (e.g., Labails et al., 2010), may indicate Early N. Atlantic TS GoM Jurassic opening. This fit also aligns a prominent linear magnetic anomaly cross- ing Yucatan (Fig. 3) with the similar anom- C. Atlantic aly marking the Appalachian fold belt front (Steltenpohl et al., 2013). Phase 2 (Fig. 3B): Pronounced counter- Eq. Atlantic clockwise (CCW) rotation of Yucatan about a pole in the Florida Straits, splitting the once-contiguous Callovian salt basin. Seafloor spreading during this phase is now widely accepted due, for example, to S. Atlantic satellite gravity data (Sandwell et al., 2014). These data reveal abandoned spreading axis segments and fracture zones constraining the post-salt kinematics. Paleomagnetic data (e.g., Molina-Garza et al., 1992) indi- cate that Yucatan rotated 78 ± 11º CCW since the Permian, of which 63º occurred after Middle Jurassic. This rotation is reflected by the fracture zones imaged by satellite gravity data. Spreading termina- 0 2500 km tion probably occurred in the Berriasian Break-up age Active ridge Abandoned ridge (145.0–139.4 Ma), based on ODP Leg 77 Cenozoic E. Cretaceous Subduction zone L. Paleozoic orogen boreholes in the Florida Strait (Marton L. Cretaceous Jurassic Fracture / transform and Buffler, 1994). Synchronously with Figure 1. Topographic-bathymetric map of Atlantic-Arctic Oceans. The Gulf of Mexico and Canada the counter-clockwise rotation of Yucatan, Basin are located in back-arc settings, oriented at a high angle to the Paleo-Pacific subduction complementary clockwise fan-shaped zone, and were never linked to the Atlantic seafloor. The pronounced wedge-shaped oceans are situated between North and South America and North America and Eurasia, respectively. spreading probably took place in the proto- Ap—Appalachian orogen; BB—Baffin Bay; Ca—Caledonian orogen; CB—Canada Basin; EB—Eurasia Caribbean (e.g., Pindell and Kennan, 2009). basin; GoM—Gulf of Mexico; In—Innuitian orogen; LS—Labrador Sea; MPB—Makarov- The Tehuantepec transform in western Podvodnikov Basin; NEA—Northeast Atlantic; O-M—Ouachita-Marathon orogen; Su—Suwanne suture; TS—Tyrrhenian Sea; Ur—Uralian orogen. Gulf of Mexico (Figs. 2 and 3B) marks the terminal shear to Gulf of Mexico rotational opening, and forms a classic sharp transi- COBs along the original limits of the type during the early phase of opening, tion between continental and oceanic crust Middle Jurassic Louann and Campeche not the kinematics or the resultant back- (Román Ramos et al., 2009). Straddling salt bodies (e.g., Pindell and Kennan, arc basin geometry. the transform is a thick Cenozoic apron, 2009) (Fig. 2). These two salt bodies Like a number of previous workers deformed at the updip end by the Neogene formed a contiguous evaporite basin in (e.g., Molina-Garza et al., 1992; Marton Quetzalcoatl extensional system, which is the Callovian (166.1–163.5 Ma) (e.g., and Buffler, 1994; Imbert and Philippe, linked via detachments with the contrac- Salvador, 1991). Although we lean toward 2005; Pindell and Kennan, 2009; Kneller tional Mexican Ridges fold and thrust belt the “wide ocean” interpretation, it is and Johnson, 2011; Rowan, 2014) we (e.g., Salomón-Mora et al., 2009). important to note that the alternative COB favor a two-phase opening model for the Regardless of preferred fit and timing, interpretations only influence the crustal Gulf of Mexico: it is clear from refraction surveys that the www.geosociety.org/gsatoday 5 100 W 90 W 80 W Canadian Arctic margin, simultaneously n O Appalachian closing the South Anyui Sea, a former ratho rogen Ma terranes ita- arm of the paleo-Pacific Ocean between h North America and Eurasia (Figs. 4A and ac ECMA Mississippi Suture? Suwa Ou nne re 4B).