TECTONIC CONTROLS ON ALLUVIAL SYSTEMS IN A DISTAL FORELAND BASIN: THE LAKOTA AND CLOVERLY FORMATIONS (EARLY CRETACEOUS) IN WYOMING, MONTANA AND SOUTH DAKOTA

1998 ◽  
pp. 133-147 ◽  
Author(s):  
J. NATHAN WAY ◽  
PATRICK J. O’MALLEY ◽  
LEE J. SUTTNER ◽  
LLOYD C. FURER
Keyword(s):  
South Dakota ◽  
Early Cretaceous ◽  
Foreland Basin

The middle Cretaceous (110−94 Ma) evolution of Tangza Basin in the western Tibetan Plateau and implications for initial topographic growth of northern Lhasa

2020 ◽  
Author(s):  
Xu Han ◽  
Jin-Gen Dai ◽  
Jie Lin ◽  
Shi-Ying Xu ◽  
Bo-Rong Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Early Cretaceous ◽  
Volcanic Rocks ◽  
Foreland Basin ◽  
High Elevation ◽  
Alluvial Fan ◽  
Magmatic Arc ◽  
Clastic Rocks ◽  
Western Tibetan Plateau ◽  
Spinel Composition

Reconstruction of Cretaceous geological evolution of Tibetan Plateau growth is critical for assessing the effect of India-Asia collision on the formation of its high elevation. However, Cretaceous topographic evolution and geodynamic mechanism in northern Lhasa remain ambiguous. Here we present results from sedimentology, zircon U-Pb ages, and detrital Cr-spinel composition of the Tangza Formation in the western part of northern Lhasa. Sedimentary lithofacies document that orbitolinid foraminifera−limestone beds were deposited in a shallow-marine setting, while clastic rocks accumulated in an alluvial fan during the middle Cretaceous. Zircon U-Pb ages of interbedded volcanic rocks place a robust constraint on the initiation of clastic rock deposition at ca. 106 Ma. Sandstones are enriched lithic fragments with abundant volcanic grains. U-Pb ages of detrital zircon display a prominent age population at 101−130 Ma with a 120 Ma peak. These data indicate that the clastic rocks were mainly derived from northern Lhasa, including an Early Cretaceous magmatic arc. Sedimentary and provenance characteristics are most consistent with deposition in a local foreland basin. The activation of south-vergent local thrusting may be responsible for loading of the Tangza foreland basin. This thrust faulting may be associated with crustal shortening induced by the continuous convergence of Lhasa and Qiangtang since collision initiated during the Early Cretaceous. The initial uplift of western and central parts of northern Lhasa and eastern Gangdese arc occurred at ca. 106 Ma, while the widespread uplift of northern and central Lhasa probably initiated at ca. 92 Ma. The mid−Late Cretaceous uplift in Lhasa was significantly earlier than the early Cenozoic India-Asia collision.

scholarly journals Transition from Late Jurassic rifting to middle Cretaceous dynamic foreland, southwestern U.S. and northwestern Mexico

2020 ◽  
Vol 132 (11-12) ◽  
pp. 2489-2516 ◽  
Author(s):  
Timothy F. Lawton ◽  
Jeffrey M. Amato ◽  
Sarah E.K. Machin ◽  
John C. Gilbert ◽  
Spencer G. Lucas
Keyword(s):  
New Mexico ◽  
Early Cretaceous ◽  
Detrital Zircon ◽  
Late Jurassic ◽  
Foreland Basin ◽  
Border Region ◽  
Sediment Routing ◽  
Mexico Border ◽  
The U.S ◽  
Dynamic Subsidence

Abstract Subsidence history and sandstone provenance of the Bisbee basin of southwestern New Mexico, southern Arizona, and northern Sonora, Mexico, demonstrate basin evolution from an array of Late Jurassic–Early Cretaceous rift basins to a partitioned middle Cretaceous retroarc foreland basin. The foreland basin contained persistent depocenters that were inherited from the rift basin array and determined patterns of Albian–early Cenomanian sediment routing. Upper Jurassic and Valanginian–Aptian strata were deposited in three narrow extensional basins, termed the Altar-Cucurpe, Huachuca, and Bootheel basins. Initially rapid Late Jurassic subsidence in the basins slowed in the Early Cretaceous, then increased again from mid-Albian through middle Cenomanian time, marking an episode of foreland subsidence. Sandstone composition and detrital zircon provenance indicate different sediment sources in the three basins and demonstrate their continued persistence as depocenters during Albian foreland basin development. Late Jurassic basins received sediment from a nearby magmatic arc that migrated westward with time. Following a 10–15 m.y. depositional hiatus, an Early Cretaceous continental margin arc supplied sediment to the Altar-Cucurpe basin in Sonora as early as ca. 136 Ma, but local sedimentary and basement sources dominated the Huachuca basin of southern Arizona until catchment extension tapped the arc source at ca. 123 Ma. The Bootheel basin of southwestern New Mexico received sediment only from local basement and recycled sedimentary sources with no contemporary arc source evident. During renewed Albian–Cenomanian subsidence, the arc continued to supply volcanic-lithic sand to the Altar-Cucurpe basin, which by then was the foredeep of the foreland basin. Sandstone of the Bootheel basin is more quartzose than the Altar-Cucurpe basin, but uncommon sandstone beds contain neovolcanic lithic fragments and young zircon grains that were transported to the basin as airborne ash. Latest Albian–early Cenomanian U-Pb tuff ages, detrital zircon maximum depositional ages ranging from ca. 102 Ma to 98 Ma, and ammonite fossils all demonstrate equivalence of middle Cretaceous proximal foreland strata of the U.S.-Mexico border region with distal back-bulge strata of the Cordilleran foreland basin. Marine strata buried a former rift shoulder in southwestern New Mexico during late Albian to earliest Cenomanian time (ca. 105–100 Ma), prior to widespread transgression in central New Mexico (ca. 98 Ma). Lateral stratigraphic continuity across the former rift shoulder likely resulted from regional dynamic subsidence following late Albian collision of the Guerrero composite volcanic terrane with Mexico and emplacement of the Farallon slab beneath the U.S.–Mexico border region. Inferred dynamic subsidence in the foreland of southern Arizona and southwestern New Mexico was likely augmented in Sonora by flexural subsidence adjacent to an incipient thrust load driven by collision of the Guerrero superterrane.

scholarly journals Coarse-grained meandering distributive fluvial system of the basal Cedar Mountain Formation, U.S.A.

2021 ◽  
Vol 91 (11) ◽  
pp. 1188-1205
Author(s):  
Stephen P. Phillips ◽  
John A. Howell ◽  
Adrian J. Hartley ◽  
Magda Chmielewska
Keyword(s):  
Grain Size ◽  
Early Cretaceous ◽  
Foreland Basin ◽  
Fluvial System ◽  
Channel Migration ◽  
Fluvial Systems ◽  
Plan View ◽  
Cedar Mountain Formation ◽  
Lateral Channel ◽  
Net To Gross

ABSTRACT The analysis of downstream changes in ancient fluvial systems can better inform depositional models for foreland-basin systems. Herein we analyze the basal deposits of the Early Cretaceous Cedar Mountain Formation of Utah to better understand the variety of fluvial deposits present and to develop a depositional model for the Sevier foreland basin. We also evaluate the long-held interpretation of a braided origin for these deposits and document numerous examples of point-bar deposition in highly sinuous meandering rivers by analysis of large (20 to 60 km2) plan-view exposures. These plan-view exposures allow comparisons between planform and cross-sectional geometries. The study utilizes outcrop data, virtual outcrop models, and satellite imagery to develop a facies model and analyze the architecture of channel bodies in the Buckhorn Conglomerate and Poison Strip Sandstone of the Cedar Mountain Formation. We document downstream (west to east) decreases in lateral channel migration, sinuosity, channel amalgamation, grain size, and percent of fluvial channel facies (conglomerate and sandstone). Fluvial channel deposits occur arranged into larger stratal bodies: multistory–multilateral channel bodies that are dominantly composed of clast-supported conglomerate in the west to a mix of multistory, multilateral, and isolated channel bodies composed of matrix-supported conglomerate in the east. The median width of highly sinuous point bars is similar across the field area (344 m to 477 m), but the inclusion of narrower (median = 174 m), low-sinuosity bar elements in the east indicates an overall reduction in lateral channel migration and sinuosity downstream. Net-to-gross values range from 100% in much of the western outcrops to as low as 38% in the east. Paleocurrent analysis reveals a transverse (west to east) paleoflow for the study interval that merges with axial (south–north) paleoflow near the Utah–Colorado state line. We estimate 104 m3/s-scale discharge and 106 kilometer-scale drainage area for axial rivers based on paleohydraulic analysis which represents a significant part of the Early Cretaceous continental-scale drainage. The observed downstream trends in lateral channel migration, sinuosity, channel amalgamation, grain size, and net-to-gross for the basal Cedar Mountain Formation are consistent with expected trends for sinuous single-thread distributive fluvial systems and are similar to observed trends in the Jurassic Morrison Formation. Medial (Buckhorn Conglomerate) to distal (Poison Strip Sandstone) zones are preserved and span the forebulge to backbulge depozones of a foreland-basin system. Postulated deposits of the proximal distributive fluvial system have been removed during erosion of the foredeep depozone. The easternmost Poison Strip Sandstone and coeval Burro Canyon Formation represent deposits of an axial system at which western-sourced distributive fluvial systems end. Distributive fluvial systems dominate modern foreland basins, and this study suggests that they may constitute a significant proportion of ancient successions.

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