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Lower Cretaceous depositional systems of southwestern Oaxaquia, in south-central Mexico, were influenced by initiation of a continental arc on mainland Mexico and subsequent accretion of the Guerrero composite arc terrane to mainland Mexico. The Atzompa Formation, defined herein, which crops out in the Sierra de Tentzo, constitutes a succession of conglomerate, sandstone, siltstone, and limestone with Early Cretaceous fauna and detrital zircon maximum depositional ages that range 126–123 Ma (late Barremian to early Aptian). The lower part of the Atzompa records a transition from alluvial to deep lacustrine depositional environments, suggesting the early stages of an extensional basin; overlying deposits of anabranching axial fluvial systems that flowed to the NE–SE accumulated after a period of rapid subsidence in the Tentzo basin, also formerly undescribed. Fluvial facies grade up-section to tidal deposits overlain in turn by a carbonate ramp succession that contains late Barremian to early Aptian fossils. The ramp deposits of the uppermost Atzompa Formation are overlain on a sharp contact by basinal carbonates of early Albian age.The Tentzo basin, formed due to crustal extension of the overriding plate in a backarc setting, was characterized by very high rates of sedimentation (3.6 mm/yr) during the early stages of basin formation (rift initiation and rift climax), and slower rates during the development of tidal systems and the carbonate ramp (post-rift stage). Regional and local subsidence took place in the backarc region of the Zicapa magmatic arc, which was established in the western margin of Mexico by Hauterivian time. Abrupt deepening following Atzompa Formation deposition is attributed to flexural subsidence related to collision of the Guerrero composite volcanic terrane with the western margin of Mexico. Following late Aptian accretion of the Guerrero terrane to Oaxaquia, the carbonate basin eventually shallowed to become a carbonate platform that faced the Gulf of Mexico.

The Upper Cretaceous (lower Campanian) Drip Tank Member of the Straight Cliffs Formation in the Grand Staircase region of southern Utah is an upward-coarsening, sandstone-rich, low-sinuosity fluvial deposit in the Cordilleran foreland basin. The Drip Tank Member thins from 75 m to 30 m eastward across the basin foredeep, approximately parallel to its dominant eastward sediment-dispersal direction, and thins southward along the foredeep to as little as 17 m near its southern outcrop extent along modern cliff lines. It overlies and underlies mudstone-rich fluvial strata of the John Henry Member of the Straight Cliffs Formation and lower member of the Wahweap Formation, respectively, both of which were deposited by northeast-flowing rivers. The John Henry–Drip Tank contact lies in an interfingering, progradational stratigraphic transition from medium-grained lenticular sandstone bodies to tabular coarse-grained amalgamated sandstone bodies. The contact with the overlying Wahweap Formation is locally a prominent surface of erosion or sediment reworking. Sandstone petrography and detrital-zircon age populations of the strata indicate detrital sources in basement south of the foreland basin, thrust sheets to the west, and magmatic arc rocks to the southwest. The uppermost part of the John Henry Member contains as much as 10% feldspar and abundant ∼ 1.84–1.60 Ga detrital zircons derived from Yavapai–Mazatzal basement rocks in the Mogollon Highlands. The Drip Tank Member ranges from quartzarenite to chert-bearing sublitharenite with Grenville (∼ 1.2–1.1 Ga), Neoproterozoic and early Paleozoic detrital zircons derived from Proterozoic through Jurassic strata exposed in the Sevier orogenic belt. Lower member Wahweap litharenites contain abundant thrust-belt-derived detrital carbonate grains absent from compositionally mature Drip Tank sandstones, as well as a broad range of zircon ages. The Drip Tank Member constitutes deposits of a sand-rich, fluvial megafan, or distributive fluvial system, that displaced a subjacent, but partly time-equivalent axial-fluvial system eastward as the megafan, driven in part by seasonally high discharge fed by monsoonal precipitation, prograded across the basin foredeep. A thick, amalgamated fan-axis succession present in northern exposures contrasts with a thinner fan-flank succession in southern localities. Tabular sixth–order lithosomes, each containing channels on the order of 7 m deep, define three individual fluvial fans or fan lobes in the megafan system. Younger Wahweap fluvial channels eroded uppermost Drip Tank deposits of the fan axis and fan flank. Transverse fan progradation across the foredeep recorded falling accommodation/sediment supply in an aggradational to progradational systems tract. Erosion and reworking of the upper fan surface record decreased accommodation, sediment bypass, and erosion prior to reoccupation of the foredeep by the Wahweap axial-fluvial system. The upper contact of the Drip Tank Member is thus the primary sequence boundary in this multi-component fluvial system, and the lower Wahweap represents transitional systems-tract deposits accumulated as accommodation/sediment supply increased.

Detrital zircon and petrographic provenance analysis of Upper Cretaceous (Campanian) strata corroborate correlation of the fluvial Kaiparowits Formation in southern Utah with post-Castlegate strata of the Mesaverde Group in eastcentral Utah. Sandstone samples of the Kaiparowits Formation in the Kaiparowits Plateau and Mesaverde Group (Neslen, Bluecastle Tongue of Castlegate, Farrer, and Tuscher formations) in Gray Canyon north of Green River, Utah, contain six U-Pb detrital zircon age populations ranging in age from Archean to Late Cretaceous. Thrust-belt-derived sublitharenite and quartzarenite of the lower part of the Mesaverde Group (Neslen and Bluecastle) lack or have only rare Mesozoic grains, but contain abundant Archean, Proterozoic, and Paleozoic grains that record recycling of Proterozoic, Paleozoic, and Jurassic sandstones exposed in uplifted thrust sheets to the west. South- and southwest-derived feldspathic litharenite of the Kaiparowits and Farrer formations contains Proterozoic grains and a diverse population of Mesozoic grain ages. Archean grains are rare to absent. Maximum depositional ages interpreted from young zircon grains in two Kaiparowits samples statistically overlap 40Ar/39Ar ages (76–74 Ma) from interbedded bentonitic tuffs and weighted mean ages of young grains from the Farrer Formation. Kolmogorov-Smirnoff statistics, in conjunction with young grain ages and detrital age spectra, corroborate petrographic evidence, which indicates that the Kaiparowits rivers were connected northward with a river system that deposited the Farrer Formation. The young grain ages, although imprecise, indicate that the uppermost Mesaverde Group strata of the Tuscher Formation are younger than the Kaiparowits Formation and record partitioning of the former foreland basin by Laramide uplifts.

Petrographic and dispersal data are essential to correct interpretation of mechanisms that create continental sequence-stratigraphic architecture. A case study from southern Utah demonstrates that Upper Cretaceous (upper Santonian-Campanian) alluvial successions in the southernmost part of the Cordilleran foreland basin were deposited by fluvial systems of contrasting drainage directions and provenance, and suggests that different mechanisms governed their sequence architecture. Most of the rivers flowed northeast, subparallel to the basin foredeep. Less common fluvial systems flowed to the east-southeast. The fluvial sandstones fall naturally into four petrofacies: (1) quartzofeldspatholithic (mean Qt61F19L20); (2) feldspatholithic (Qt29F19L52); (3) quartzolithic (Qt75F6L20); and (4) quartzose (Qt99F1L1). Petrofacies 1 and 2 were derived from mixed supracrustal and basement sources to the southwest and south, respectively, whereas petrofacies 3 and 4 were derived from uplifted thrust sheets of the Sevier orogenic belt to the southwest and west, respectively. Only the east-southeast-flowing rivers transported the quartzose petrofacies. The fluvial strata, which include the uppermost Straight Cliffs, Wahweap, and Kaiparowits formations, form two large-scale stratigraphic successions typically interpreted as continental stratigraphic sequences hundreds of meters thick. Each succession begins with an amalgamated braided-fluvial deposit, grades to mudstone-rich strata with low sandstone-body connectivity, and culminates in highly connected sandstone bodies with multistory stacking. The basal amalgamated deposits of each succession are architecturally similar, but their compositional and dispersal characteristics are different. Quartzofeldspatholithic, quartzolithic, and quartzose sandstones above the lower base-level shift are variable, but generally similar in compositional and dispersal characteristics to both underlying and overlying strata, a phenomenon termed here congruence. In contrast, quartzose amalgamated fluvial sandstone above the upper base-level shift differs sharply in composition and dispersal direction from underlying and overlying lithic-rich strata. The foredeep axis controlled the progradation direction of the congruent shift, which was likely driven by climatically induced sediment influx, a eustatic fall, or both. In the case of the incongruent shift, increased sediment supply permitted the rivers to cross the foredeep. Temporal association of the upper amalgamated deposit with active structures in the thrust belt and foreland basin indicates that syntectonic thrust uplift, not isostatic uplift or climate, caused the influx of quartz.

The Upper Devonian (lower Famennian) Cove Fort Quartzite and associated strata of western Utah comprise three stratigraphic sequences, each containing a thick (as much as 65 m) lowstand systems tract. Coarse-grained shoreface quartz arenite and lagoonal dolomicrite of the lowstand systems tracts display the following features characteristic of forced regression: (1) they contain coarse-grained proximal shoreline deposits that overlie an erosional surface (sequence-bounding unconformity) cut into fine-grained distal-marine carbonate facies; (2) they lie seaward of a zone of sediment bypass, and are spatially detached and separated from the previous highstand shoreface; (3) they are confined geographically to a relatively narrow zone less than 30 km wide; (4) they are onlapped and overlain by transgressive systems tract deposits consisting of deep subtidal carbonates (West Range Limestone); and (5) landward of the lowstand shoreline pinch-out, the sequence-bounding unconformity beneath them merges with a transgressive surface of erosion above them. A thick wedge of siliciclastic forced-regression deposits is present at the base of each depositional sequence. The stratigraphic position of each wedge above the basal sequence boundary was controlled by eustatic sea-level fall. The forced-regression deposits are geographically restricted to a narrow strike belt along the eastern margin of the Pilot basin, which coincides with the trace of the Cordilleran Hingeline, a zone of crustal discontinuity. The geographic confinement and unusual stratal thickness of barrier-bar complexes in the lowstand systems tract, as well as the stratigraphic stacking of the forced-regression deposits, were controlled by flexurally induced high subsidence rates focused at the Cordilleran Hingeline.