Sediment routing from hinterland to the deep sea is complicated because it involves evolution of river drainage from source areas to coastal plains and sediment mixing on the shelf and slope by marine currents. Previous regional paleogeographic mapping in the Gulf of Mexico (GOM) has observed a >150 km offset between the middle Miocene paleo‐Tennessee fluvial axis and the associated deep‐sea fan depositional axis, indicating a complicated sediment pathway. We integrate new and published detrital zircon (DZ) U‐Pb age data from fluvial, shelf and deep‐sea deposits to examine the complex Miocene sediment routing system in the northern GOM. These data suggest an increase in sediment load derived from western North America (increased Western Cordillera terranes; <300 Ma zircon age component) from the early to middle Miocene in the deep‐water Green Canyon protraction area. The early Miocene Green Canyon area received sediments mainly from fluvial axes located directly updip: the paleo‐Mississippi River (44%–56%; characterized by Yavapai‐Mazatzal, Mid‐Continent and Western Cordillera sourced 1800–1600 Ma, 1500–1300 Ma and <300 Ma, respectively, and Grenville‐Appalachian sourced 1300–950 Ma and 500–300 Ma age components) and smaller rivers and tributaries draining the Appalachian Mountains (e.g. paleo‐Tennessee River, 18%–43%; mainly Grenville‐Appalachian sourced 1300–9500 Ma and 500–300 Ma age components). In contrast, the middle Miocene Green Canyon deep‐sea fan shows a strong DZ signal from the paleo‐Red River (38%; increased <300 Ma zircon age component), which requires input of additional sediment sources from west of the paleo‐Mississippi system. In addition, the paleo‐Tennessee River, which was a major middle‐Miocene sediment source for the central‐eastern GOM due to uplift and increased erosion of the Appalachian Mountains, is underrepresented (34%; decreased 1300–950 Ma zircon age component) in the middle Miocene Green Canyon fan. We suggest that two mechanisms combined to produce the increased middle Miocene input from western sediment sources and restriction of locally up‐dip Tennessee River sources: (1) regional drainage changes involving middle Miocene capture of the paleo‐Red River and its tributaries by the paleo‐Mississippi River, which at the same time lost some of its eastern tributaries owing to expansion of the paleo‐Tennessee and (2) eastward (clockwise) marine transport of western‐sourced sediment along the shelf or slope, which deflected the paleo‐Tennessee signal >150 km eastward to feed the deep‐sea fan further east, perhaps reflecting intensification of a precursor to the GOM Loop Current.
It is well established that sedimentary margins grow by sediments bypassing through shelf-and slope-incising canyons onto the basin floor and by sediments being deposited incrementally across clinoforming and pro-grading margins. However, we argue that these two distinctive types of deep-water sediment supply to the basin floor and to the margin are generally not operating at the same time and should not be seen as integral parts of a single model. When shelf-incising canyons were actively bypassing sediments across the margin, the margin itself was not prograding, and vice versa. We present stratigraphic data for some 111 global examples of shelf-and slope-incising canyons and their linked basin-floor sediments, and we provide criteria to distinguish them from prograding margins fed by shelf-edge deltas and their linked slope channels and toe-of-slope fans. The defining character of the canyon feeding system is basin-floor sediment aggradation and the onlapping of this stratigraphy against an eroded basin margin. For many of our examples this onlap persists for millions to tens of millions of years and is especially prolonged in periods of persistent high eustatic sea level. This is in clear contrast to the downlapping stratigraphy that dominates during intervals of high sediment supply from the shelf, and active margin accretion. Some 60% of the ancient canyon/basin-floor fan systems are inferred to have been sourced by canyons tapping longshore drift in littoral cells; they are inferred because with canyon capture, tapped littoral cells are generally depleted and not preserved. In other cases, shelf-incising canyons tapped documented deltas on the inner or middle shelf, but in some other cases, a deltaic or riverine source was inferred. Canyon cutting and initial sediment bypass through the canyons are chiefly associated with initially ?out-of-grade? margins?for example, where a carbonate margin has foundered and oversteepened or where large-scale collapse of aggradational and oversteepened clastic shelf edges occurred. Canyon feeding onto the basin floor is linked with runout of basin-floor fans to the basin center, in contrast to direct-fed prograding margins, where sediment is continuously partitioned onto and across the entire shelf-edge, slope, and toe-of-slope areas.
The Gulf of Mexico petroleum habitat is broad and diverse, with virtually every depositional unit or supersequence producing hydrocarbons onshore or offshore in the USA, Mexico, or Cuba. Oil and gas fields and undiscovered resources follow a concentric trend, with Mesozoic hydrocarbons resources surrounding the prolific Cenozoic basin center. The most recent and expected future discoveries are in the deepwater subsalt domain of the USA and Mexico, though a potential pre-salt frontier remains to be tested. Characterization of emerging (deepwater Tuscaloosa and Norphlet), existing (deepwater Wilcox), and mature (Plio-Pleistocene minibasin) conventional exploration plays yields new insights but also important exploration lessons, such as the Perdido fold belt BAHA wells, which ultimately set-up deepwater Wilcox exploration in the Gulf of Mexico, with large discoveries as recently as 2017. Unconventional onshore plays are well-established (Eagle Ford), emerging (Agua Nueva), or technically challenged (Tuscaloosa Marine Shale). The seismic technology evolution that underpins current success in the subsalt of the US sector will undoubtedly impact new exploration in the Campeche salt province of Mexico.
The Gulf of Mexico Basin is one of the most prolific hydrocarbon-producing basins in the world, with an estimated endowment of 200 billion barrels of oil equivalent. This book provides a comprehensive overview of the basin, spanning the US, Mexico and Cuba. Topics covered include conventional and unconventional reservoirs, source rocks and associated tectonics, basin evolution from the Mesozoic to Cenozoic Era, and different regions of the basin from mature onshore fields to deep-water subsalt plays. Cores, well logs and seismic lines are all discussed providing local, regional and basin-scale insights. The scientific implications of seminal events in the basin's history are also covered, including sedimentary effects of the Chicxulub Impact. Containing over 200 color illustrations and 50 stratigraphic cross-sections and paleogeographic maps, this is an invaluable resource for petroleum industry professionals, as well as graduate students and researchers interested in basin analysis, sedimentology, stratigraphy, tectonics and petroleum geology.
Twenty-seven marine and 23 lacustrine clinothem pairs were recognized and analyzed in Qiongdongnan Basin and Pannonian Basin, respectively. A comparison of their architecture highlighted some critical differences in sediment delivery and partitioning between the marine and closed lacustrine basins. In marine Qiongdongnan Basin, rising but forward-moving shelf-edge trajectories and clinoforms with a height of hundreds of meters commonly link downdip to absent or limited sandy bottomsets, whereas the opposite occurs in the lacustrine Pannonian Basin, where very thick bottomsets developed in front of highly aggradational clinoforms. A further comparison of strongly progradational clinothem sets with fairly flat shelf-edge trajectories suggests that relatively thick versus thin or absent sandy bottomsets occur in the marine and lacustrine settings, respectively. The main reason for this marked contrast in sediment partitioning across marine versus lacustrine clinoforms is climate, where a wet-dry climate model needs to be used to explain sediment dispersal to the floor of deep Lake Pannon. During the humid half-cycle, catchment precipitation and sediment flux into Lake Pannon were probably high, and coeval lake-level rise and reduced salinity likely increased shelf accommodation and caused topset aggradation of the forward-moving clinothems. This, in turn, resulted in enhanced hyperpycnal flows and thick bottomsets on the lake-basin floor. During the semiarid half-cycle, lake level was fairly stable, and both the catchment precipitation and sediment flux into Lake Pannon were probably reduced, causing some increase in the salinity, less frequent hyperpycnal flows, and resultant short downlapping clinothems lacking or with only thin bottomsets. Critical differences in sediment delivery and partitioning between marine and lacustrine basins, as highlighted by a comparison of aggradational to progradational clinothem pairs documented herein, draw attention to the pitfall of mechanically applying conventional marine sequence stratigraphy to lacustrine basins.
Fluvial systems represent a key component in source-to-sink analysis of ancient sediment-dispersal systems. Modern river channels and channelrelated deposits possess a range of scaling relationships that reflect drainage-basin controls on water and sediment flux. For example, channel-belt sand-body thicknesses scale to bankfull discharge, and represent a reliable first-order proxy for contributing drainage-basin area, a proxy that is more robust if climatic regimes can be independently constrained. A database of morphometrics from Quaternary channel belts provides key modern fluvial system scaling relationships, which are applied to Cretaceousto Paleocene-age fluvial deposits. This study documents the scales of channel-belt sand bodies within fluvial successions from the northern Gulf of Mexico passive-margin basin fill from well logs, and uses scaling relationships developed from modern systems to reconstruct the scale of associated sediment-routing systems and changes in scale through time. We measured thicknesses of 986 channel-belt sand bodies from 248 well logs so as to estimate the scales of the Cretaceous (Cenomanian) TuscaloosaWoodbine, Paleocene–early Eocene Wilcox, and Oligocene Vicksburg-Frio fluvial systems. These data indicate that Cenozoic fluvial systems were significantly larger than their Cenomanian counterparts, which is consistent with Cretaceous to Paleocene continental-scale drainage reorganization that routed water discharge and sediment from much of the continental United States to the Gulf of Mexico. At a more detailed level, Paleocene–early Eocene Wilcox fluvial systems were larger than their Oligocene counterparts, which could reflect decreases in drainage-basin size and/or climatic change within the continental interior toward drier climates with less runoff. Additionally, these data suggest that the paleo–Tennessee River, which now joins the Ohio River in the northernmost Mississippi embayment of the central United States, was an independent fluvial system, flowing southwest to the southern Mississippi embayment, or directly to the Gulf of Mexico, through the early Eocene. Changes in scaling relationships through time, and interpreted changes in the scales of contributing drainage basins, are generally consistent with previously published regional paleogeographic maps, as well as with newly published maps of paleodrainage from detrital-zircon provenance and geochronological studies. As part of a suite of metrics derived from modern systems, scaling relationships make it possible to more fully understand and constrain the scale of ancient source-to-sink systems and their changes through time, or cross-check interpretations made by other means.