Marine Sedimentary Basins

Marine Sedimentary Basins Paul Mann* Department of Earth and Atmospheric Sciences, 312 Science & Research 1, University of Houston, Houston, TX, USA Synonyms Active margin basins; Oceanic basins; Passive margin basins; Submarine basins Definition Marine sedimentary basins are any modern basin that is currently below sea level and influenced by marine sedimentary processes and sedimentation. Many ancient marine sedimentary basins are now deformed and uplifted into modern, mountain chains as part of ongoing or ancient orogenic or mountain-building processes. The modern marine sedimentary basins of the world s ocean basins can be subdivided into continental shelves, slopes, rises, abyssal plains, and oceanic trenches in passive margin settings (Fig. 1). As these topics have been defined and discussed by other authors of the encyclopedia, I will focus on the origin of the main tectonic classes of marine sedimentary basins in active margin settings that include those produced in rift, collisional, subduction, and strike-slip environments, along with bolide impacts into marine environments (Fig. 1). Actively subsiding environments of modern marine sedimentary basins are commonly found near continent ocean boundaries and land sea interfaces, and for that reason, these basins can exhibit rapid alternations between marine and continental depositional systems. A common sequence of events in the life stages of a basin is to move from initial subsidence with filling by continental sediments to marine incursion as the basin moves below sea level often as the consequence of accelerated tectonic subsidence and back to continental sedimentation as the basin either moves above sea level as the result of tectonic deformation or eventually fills to capacity as the rate of continental and marine sedimentation exceeds its rate of subsidence. The examples below illustrate basins near continent ocean boundaries and near land sea interfaces that are in the process of sedimentary transitions from nonmarine to marine or vice versa (Fig. 1). Continental and Marine Rift Basins: Basins Formed by Stretching The East African rift is the archetypal, continuous, and branching continental rift formed by stretching of continental crust extending 4 km across East Africa (Fig. 2a). Extension is linked to the rise of the mantle-derived African superplume that became active in mid-cenozoic time. GPS results from Saria et al. (214) show east west opening of the rifts relative to the African plate to the west along a twin zone of rifting in East Africa (Fig. 2b). The northern terminus of the rift in the Afar area is locally 155 m below sea level and influenced by periodic marine incursions that have led to evaporite deposits. As the rift progressively opens, marine *Email: pmann277@gmail.com Page 1 of 11

Fig. 1 Map of passive (green) and active (red) margins of the world modified from passive margin compilation by Bradley (28). Stars show largest earthquakes since 197 that are confined to the active plate margins shown with red shading incursions will progress further and further to the south along the rift axis and converting the rift from a nonmarine to a marine basin (Fig. 2b). The cross section in A and B from Saria et al. (214) shows the typical structure of East Africa with either a half-graben structure or a full-graben structure. In inland areas of the African continent, the rift fills are removed from marine influence and remain continental. Failed Rift Basins: Basins Formed by Stretching The West Siberian basin is a large failed rift system formed by rifting during the Permian Triassic period as the result of a failed breakup of the northern Eurasia continent (Mann et al., 23). As with many failed rifts, the West Siberian basin forms a multi-branched zone of rifting extending hundreds of kilometers into a continental area where fault-bounded rifts narrow and eventually terminate. Much of the rifted areas are overlain by a thick and less faulted sag basin filled by marine sedimentary rocks. The thickness of the sag basin is controlled by thermal subsidence that produces a large, bowlshaped marine sedimentary basin overlying the underlying and elongate, parallel rifts (Fig. 3a). The sag basin is relatively symmetrical with respect to the location of the underlying rifts that again reflects its origin by thermal subsidence (Fig. 3a). Widespread volcanic rocks related to the lithospheric thinning during the rifting event are present both on the eastern rift flank and underlying the sag basin as shown in the stippled pattern on the cross section in Fig. 3b (Reichow et al., 22). Page 2 of 11

a 2 E 25 E 3 E 35 E 4 E 45 E 5 E 55 E 15 N 1 N 5 N 5 S 1 S 15 S 2 S 8 km Legend 2 mm/yr GPS Vectors Major World Faults Plate Boundaries (from Bird 22) Country Boundaries Cross Sections (Fig 4B) Topo / Bathy 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 Volcanoes Active Potentially active Solfatara stage b Northern MER A NW 4 2 2 4 km Central MER B 4 2 2 4 km W Guraghe border fault Syn-rift volcanics Boseti magmatic segment WFB Asela border fault Arboye border fault 5 1 15 km Mt Chilalo 5 1 15 km SE A Pre-rift volcanics (Eocene-Oligocene) Syn-rift volcanics (Miocene-Pliocene) Syn-rift volcanics (Pliocene-Pleistocene) E B Fig. 2 Tectonic map of the East African rift system modified from Saria et al. (214). Yellow lines indicate active rift faults, and black arrows show GPS velocities relative to a fixed Africa plate. The Afar rift at the northern end of the East African rift system is locally 155 m below sea level and subject to marine incursions. Marine influence will likely expand southward along the topographically depressed rift axis as the rift widens in an east west direction Page 3 of 11

a 6 E 65 E 7 E 75 E 8 E 85 E 9 E 75 N 7 N 65 N 6 N 55 N 5 km b T X? Legend West Siberian Basin SG 6 Cross section (Fig 5B) Country Boundaries Triassic Rifts Sediment Thickmess (from Laske and Masters. 1997) Topo / Bathy m 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 Siberian Platform Paleozoic Basement T X Fig. 3 Tectonic map of the failed West Siberian rift basin modified from Laske and Masters (1997) and Mann et al. (23) with colors illustrating the thickness variations in the thick sag basin overlying the three elongate rifts shown in gray. East west cross section from Reichow et al. (22) shows the underlying rifts, an overlying, marine sag basin, and the presence of widespread volcanic rocks in stipple pattern both on the eastern rift flank and beneath its central sag basin Page 4 of 11

Collision-Related Basins: Basins Formed by Flexure Some of the largest marine and nonmarine basins formed on continental crust are foreland basins produced by the downward flexing of the edge of a continent in response to the overthrusting and loading by a colliding continent, arc, or terrane. The northern margin of the South American continent in the countries of Colombia, Venezuela, and Trinidad provides an excellent regional example of the continental flexure of the continental crust of the South American plate beneath the diachronously colliding Great Arc of the Caribbean (Escalona and Mann 211) (Fig. 4). Foreland basins in this area are highly asymmetrical with the deeper edge of the foreland basin controlled by thrust faults of the colliding arc block in the north near the coast of the Caribbean Sea and the more gently sloping edge of the basin in the south controlled by the flexed area of continental crust. Marine rocks in foreland basins like the eastern Venezuelan basin were deposited during the underfilled stage of basin development when thrusting and depression of continental crust beneath the basin reached a climax and outpaced the rate of sedimentation (Escalona and Mann 211). As the zone of deformation between the northern South American continent and the obliquely colliding Great Arc of the Caribbean moved progressively eastward, the tectonically controlled subsidence rate waned, and the basin filled to sea level with both marine and nonmarine sediments (Fig. 4). Presently the central and eastern part of the foreland basin in Venezuela is filled to sea level and forms a broad, alluvial plain with the Orinoco delta at its eastern end adjacent to the Atlantic Ocean (Fig. 4). Subduction-Related Basins: Basins Formed by Stretching Subduction-related basins generally form by processes of extension linked to the underlying, extensional process of slab rollback or steepening of the subducting slab that underlies the arc system. Extension produces back-arc basins like the Grenada basin and forearc basins like the Tobago basin that are fully marine in intraoceanic settings as the Lesser Antilles arc shown in Fig. 5 and discussed by Aitken et al. (211). Although occupying a much different tectonic setting, subduction-related basins form by the same processes of stretching that are observed in continental rift basins like the East African rift (Fig. 2) and West Siberian basin (Fig. 3). Strike-Slip Basins: Basins Formed by Stretching and Flexure Strike-slip basins formed in marine and nonmarine basins may form by stretching as in the case of pullapart basins or can form by flexure in restraining bend settings where thrust faulting and folding dominates. The California strike-slip margin includes examples of both nonmarine basin types in areas of elevated mountains along the controlling and central San Andreas strike-slip fault and deep marine basins of pull-apart origin in the California borderlands offshore of southern California and in the pullapart basin province of the centerline of the Gulf of California (Mann, 27) (Fig. 6). Restraining bend tectonics in the Big Bend area of southern California is dominated by thrusting and flexure of adjacent basins beneath uplifted mountain blocks. For this reason, the depth to basement is greater in the restraining bend areas than in the more extensional areas offshore (Fig. 6). The line of deeper basins parallel to the coast of California in the Pacific Ocean reflects the trace of a relict subduction margin that preceded the current phase of strike-slip motion along the onland San Andreas strike-slip fault zone (Mann, 213) (Fig. 6). Page 5 of 11

9 85 8 75 7 65 6 25 North American plate Atlantic Ocean 2 2 3 15 1 Caribbean plate 3 4 5 6 7 SMM APP NR 1 SJB LN CCO SI SB SM MA 2 3 4 Pacific ocean CC 5 WC EC 1 South American plate Sense of horizontal displacement Relative plate motion Inferred paths of Proto-Orinoco River 14 N 75 W 7 W 65 W 6 W 55 W Lesser Antilles arc system Depth to basement (in meters) Value High : 2 m 12 N Low : 12 m 1 N 8 N 6 N Eastern Venezuela foreland basin 2 km Fig. 4 Map showing the leading edge of the Great Arc of the Caribbean as it progressively and obliquely collided from west to east with the northern, continental margin of South America. Numbers represent the time that the intraoceanic Great Arc of the Caribbean occupied this location: 1, late Cretaceous; 2, Paleocene; 3, Eocene; 4, Oligocene; 5, Miocene; 6, Pliocene; and 7, present day. Depth to basement map for the top of crystalline continental crust of northern South America and the offshore area occupied by the Great Arc from Escalona and Mann (211). The eastern Venezuelan basin is a large, foreland basin formed by the flexure of the continental edge of northern South America beneath the colliding Great Arc. Marine influence in the foreland basin is greatest during times of basin deepening that accompany periods of maximum thrusting and lithospheric flexure Page 6 of 11

66 W 64 W 62 W 6 W 58 W 18 N 16 N Lesser Antilles volcanic arc 14 N Grenada backarc basin 12 N Barbados accretionary prism 1 N Tobago forearc basin 2 km Legend Earthquake Depth Earthquake Magnitude Topo / Bathy Shallow depth Intermediate depth Active Volcanoes Major World Faults and CBTH 214 basement faults Plate Boundaries (from Bird 22) 4-5 5-6 6-7 7-8 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 Fig. 5 Map of the Lesser Antilles island arc modified from Aitken et al. (211) showing major basins formed mainly by the extensional process of slab rollback beneath the arc system. Arc-related basins are formed by stretching of the arc lithosphere as the subducting slabs rolls back in an eastward direction Page 7 of 11

125 W 12 W 115 W 4 N 38 N 36 N 34 N 32 N Depth to Basement, Depth to Basement, Depth to Basement, Offshore (TWT) Los Angeles basin (ft.) San Joaquin basin (ft). Value High : 6 s Value High : 18 ft. Value High : 1 ft. Low : 1 s Low : 3 ft. Low : ft. Thrust margin Active faults Fig. 6 Map of the active right-lateral, strike-slip San Andreas Fault system of California showing variations in depth to basement along the fault system modified from Mann (213). Most strike-slip basins are small and formed as a consequence of either localized shortening or extension along strike-slip faults. The deepening of basins in the area of the southern San Andreas Fault is related to shortening-related flexure produced by the prominent restraining bend in that area Basins Produced by Submarine Bolide Impacts Bolide impacts into marine areas can produce deep marine basins as illustrated in the 18 2 km-wide Chicxulub impact crater of latest Cretaceous age in the offshore of the Yucatan Peninsula in the Gulf of Mexico (Fig. 7). Cross sections of the crater show a multi-ringed structure with a central structural uplift that is greater than 1 km and a Moho displaced by 1 2 km (Gulick et al., 213). The outer rim produced during impact produced a belt of large slump blocks. Impact deposits along with normal marine sedimentation eventually filled the crater with marine sedimentary rocks up to 3 km in thickness (Fig. 7). Page 8 of 11

91 W 9 W 89 W 88 W 23 N 22 N 21 N Chicxulub Puerto Mérida 2 N 7 km Legend Key Ring Features (from Gulick et al., 213) Cenozoic basin Exterior Ring and Inner Rim Peak Ring Cenotes and Sinkholes (from Connors et al., 1996) Country Boundaries Cross Section Wells Topo / Bathy m 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 A Impact breccia Yax-1 Y-6 Peak ring Width of structural uplift Impact breccia impact melt rocks A Post-impact sediments Cretaceous rocks Depth (km) Upper crust Mid crust Lower crust Mid crust Upper crust Upper crust Mid crust 2 2 4 6 8 1 Distance (km) 12 14 16 18 Fig. 7 Map and cross section of Chicxulub impact crater of latest Cretaceous age in the offshore of the Yucatan Peninsula in the Gulf of Mexico modified from Gulick et al. (213). Marine sedimentary basins produced by bolides are comparable in size to strike-slip basins but smaller than foreland basins Page 9 of 11

Summary of Marine Sedimentary Basins Marine sedimentary basins form by a variety of tectonic processes including lithospheric stretching in rift (Figs. 2 and 3), strike-slip (Fig. 6), and subduction (Fig. 5) settings and by lithospheric flexure in collisional (Fig. 4) and strike-slip (Fig. 6) settings. The sizes of marine sedimentary basins in foreland or collisional settings are generally much larger than either rift, strike-slip, or bolide impacts in marine settings (Fig. 7). The degree of marine fill of these basins is directly related to the proximity of the basin to marine waters. Marine waters can flow into the axis of a juvenile rift or foreland basin during its earlier underfilled stage. Non-marine fill can fill the basin to sea level during its later, overfilled stage. Cross-References Active Continental Margin Intracontinental Rifting Morphology Across a Convergent Plate Boundary Passive Plate Margin Pull-Apart Basin Shelf Subduction Subsidence: Marine Geosciences Bibliography Aitken, T., Mann, P., Escalona, A., and Christeson, G., 211. Evolution of the Grenada and Tobago basins and implications for arc migration. Marine and Petroleum Geology, 28, 235 258. Bradley, D., 28. Passive margins through earth history. Earth-Science Reviews, 91, 1 26. Escalona, A., and Mann, P., 211. Tectonics, basin subsidence mechanisms, and paleogeography of the Caribbean-South American plate boundary zone. Marine and Petroleum Geology, 28, 8 39. Gulick, S., Christeson, G., Barton, P., Grieve, R., Morgan, J., and Urrutia-Fucugauchi, J., 213. Geophysical characterization of the Chicxulub impact crater. Reviews of Geophysics, 51, 31 52. Laske, G., and Masters, G., 1997. A global digital map of sediment thickness: EOS. Transactions of the American Geophysical Union, 78, 483. Mann, P., Gahagan, L., and Gordon, M., 23. Tectonic setting of the world s giant oil and gas fields. In Halbouty, M. T. (ed), Giant Oil and Gas Fields of the Decade, 199 1999. AAPG Memoir 78, Tulsa, Oklahoma, pp. 15 15. Mann, P., 27. Global catalogue, classification, and tectonic origins of restraining and releasing bends on active and ancient strike-slip fault systems. In Cunningham, W., and Mann, P. (eds), Tectonics of Strikeslip Restraining and Releasing Bends. London: Geological Society. Special Publications, Vol. 29, pp. 13 142. Page 1 of 11

Mann, P., 213. Comparison of structural styles and giant hydrocarbon occurrences within four, active strike-slip regions: California, Southern Caribbean, Sumatra, and East China. In Gao, D. (ed), Dynamic Interplay among Tectonics, Sedimentation, and Petroleum Systems. AAPG Memoir 1, pp. 43 93. Reichow, M., Saunders, A., White, R., Pringle, M., Al Mukhamedov, A., Medvedev, A., and Kirda, N., 22. 4 Ar/ 39 Ar dates from the West Siberian basin: Siberian flood basalt province doubled. Science, 296, 1846 1849. Saria, E., Calais, E., Stamps, D., Delvaux, D., and Hartnady, C., 214. Present-day kinematics of the East African rift. Journal of Geophysical Research, Solid Earth. 119, doi:1.12/213jb191. Page 11 of 11