Littérature scientifique sur le sujet « Paleodrainage analysis »

Ancient drainage systems are being increasingly documented in the Amazon basin and their characterization is crucial for reconstructing fluvial evolution in this area. Fluvial morphologies, including elongate belts, are well preserved along the Madeira River. Digital Elevation Model from the Shuttle Radar Topography Mission favored the detection of these features even where they are covered by dense rainforest. These paleomorphologies are attributed to the shifting position of past tributaries of the Madeira River through avulsions. These radial paleodrainage networks produced fan-shaped morphologies that resemble distributary megafans. Distinguishing avulsive tributary systems from distributary megafans in the sedimentary record is challenging. Madeira´s paleodrainage reveals the superposition of tributary channels formed by multiple avulsions within a given time period, rather than downstream bifurcation of coexisting channels. Channel avulsion in this Amazonian area during the late Quaternary is related to tectonics due to features as: (i) straight lineaments coincident with fault directions; (ii) northeastward tilting of the terrain with Quaternary strata; and (iii) several drainage anomalies, including frequent orthogonal drainage inflections. These characteristics altogether lead to propose that the radial paleodrainage present at the Madeira River margin results from successive avulsions of tributary channels over time due to tectonics.

The paper represents a geomorphological study related to the transitional forms between fluvial and karstic process. Karst areas of eastern Serbia are distributed in a large number of relatively isolated segments, and therefore abound in contact karst features. In many cases, central parts of karst areas, away from the contacts, host a variety of relict and dry valleys. Morphological analysis of these valleys may reveal the remnants of paleodrainage networks and help to reconstruct the morphological evolution of the area. This is a case study of the karst of Miroč Mt. in north-eastern Serbia, where geomorphological analysis and relief visualization using the Geomorphological Information System enabled the detection of paleodrainage directions and patterns in the vicinity of the Danube Gorge. Three paleo-river systems were detected, the largest of which is that of the Suva Reka (51 km2).

Abstract The Žerotice Formation recognised in a confined area NE–SE of Znojmo represents a basal member of the sedimentary succession of the southwestern margin of the Carpathian Foredeep in Moravia (Czech Republic). Two facies associations were recognised within the formation. The first one mantles the pre-Neogene basement with an irregular unconformity, reflects arid climatic conditions and deposition of episodic shallow, high-energy stream flows and/or mass flows (alluvial to fluvial deposits). The second facies association is interpreted as lagoonal to distal flood plain deposits. The barren unfossiliferous deposits of the Žerotice Formation are covered by nearshore marine Eggenburgian deposits. The boundary between these deposits represents a sequence boundary (i.e. the basal forebulge unconformity). Detailed provenance studies of successive beds below and above this sequence boundary showed differences in the source area and paleodrainage. Both the local primary crystalline rocks (Moravian and Moldanubian Unit, Thaya Batholith) and older sedimentary cover (especially Permo–Carboniferous sedimentary rocks) form the source of the Žerotice Formation. All these geological units are located only a few km away from the preserved areal extent of the deposits of the Žerotice Formation (short transport and a local source). The source areas of the overlying marine Eggenburgian beds are located far more to the W and NW in the Moldanubian and Moravian Units (longer transport, extended source area). Local confined preservation of the Žerotice Formation is preliminarily explained as connected with a tectonically predisposed paleovalley.

Abstract Sedimentological analysis of the Missão Velha Formation (Araripe Basin, northeast Brazil) is the aim of this paper through detailed facies analysis, architectural elements, depositional systems and paleocurrent data. The main facies recognized were: (i) coarse-grained conglomeratic sandstones, locally pebbly conglomerates, with abundant silicified fossil trunks and several large-to-medium trough cross-stratifications and predominantly lenticular geometry; (ii) lenticular coarse-to-medium sandstones with some granules, abundant silicified fossil wood, and large-to-medium trough cross-stratifications, cut-and fill features and mud drapes on the foresets of cross-strata, (iii) poorly sorted medium-grained sandstones with sparse pebbles and with horizontal stratification, (iv) fine to very fine silty sandstones, laminated, interlayered with (v) decimetric muddy layers with horizontal lamination and climbing-ripple cross-lamination. Nine architectural elements were recognized: CH: Channels, GB: Gravel bars and bed forms, SB: Sand bars and bedforms, SB (p): sand bedform with planar cross-stratification, OF: Overbank flow, DA: Downstream-accretion macroforms, LS: Laminated sandsheet, LA: Lateral-accretion macroforms and FF: Floodplain fines. The lithofacies types and facies associations were interpreted as having been generated by alluvial systems characterized by (i) high energy perennial braided river systems and (ii) ephemeral river systems. Aeolian sand dunes and sand sheets generated by the reworking of braided alluvial deposits can also occur. The paleocurrent measurements show a main dispersion pattern to S, SE and SW, and another to NE/E. These features imply a paleodrainage flowing into the basins of the Recôncavo-Tucano-Jatobá.

Enigmatic successions of deep-water strata referred to as the Nesmith beds and Grant Land Formation comprise the exposed base of the Franklinian passive margin sequence in northern Ellesmere Island, Nunavut. To test stratigraphic correlations with Ediacaran to Cambrian shallow-water strata of the Franklinian platform that are inferred by regional basin models, >500 detrital zircons from the Nesmith beds and Grant Land Formation were analyzed for sediment provenance analysis using laser ablation (LA–ICP–MS) and ion-microprobe (SIMS) methods. Samples of the Nesmith beds and Grant Land Formation are characterized by 1000–1300, 1600–2000, and 2500–2800 Ma detrital zircon age distributions and indicate provenance from rock assemblages of the Laurentian craton. In combination with regional stratigraphic constraints, these data support an Ediacaran to Cambrian paleodrainage model that features the Nesmith beds and Grant Land Formation as the offshore marine parts of a north- to northeast-directed depositional network. Proposed stratigraphic correlations between the Nesmith beds and Ediacaran platformal units of northern Greenland are consistent with the new detrital zircon results. Cambrian stratigraphic correlations within northern Ellesmere Island are permissive, but require further investigation because the Grant Land Formation provenance signatures agree with a third-order sedimentary system that has been homogenized by longshore current or gravity-flow processes, whereas coeval shallow-water strata yield a restricted range of detrital zircon ages and imply sources from local drainage areas or underlying rock units. The detrital zircon signatures of the Franklinian passive margin resemble those for the Cordilleran and Appalachian passive margins of Laurentia, which demonstrates the widespread recycling of North American rock assemblages after late Neoproterozoic continental rifting and breakup of supercontinent Rodinia.

As a Quaternary repository of wind-reworked Indus River sand at the entry point in the Himalayan foreland basin, the Thal Desert in northern Pakistan stores mineralogical information useful to trace erosion patterns across the western Himalayan syntaxis and the adjacent orogenic segments that fed detritus into the Indus delta and huge deep-sea fan throughout the Neogene. Provenance analysis of Thal Desert sand was carried out by applying optical and semi-automated Raman spectroscopy on heavy-mineral suites of four eolian and 11 fluvial sand samples collected in selected tributaries draining one specific tectonic domain each in the upper Indus catchment. In each sample, the different types of amphibole, garnet, epidote and pyroxene grains—the four dominant heavy-mineral species in orogenic sediment worldwide—were characterized by SEM-EDS spectroscopy. The chemical composition of 4249 grains was thus determined. Heavy-mineral concentration, the relative proportion of heavy-mineral species, and their minerochemical fingerprints indicate that the Kohistan arc has played the principal role as a source, especially of pyroxene and epidote. Within the western Himalayan syntaxis undergoing rapid exhumation, the Southern Karakorum belt drained by the Hispar River and the Nanga Parbat massif were revealed as important sources of garnet, amphibole, and possibly epidote. Sediment supply from the Greater Himalaya, Lesser Himalaya, and Subhimalaya is dominant only for Punjab tributaries that join the Indus River downstream and do not contribute sand to the Thal Desert. The detailed compositional fingerprint of Thal Desert sand, if contrasted with that of lower course tributaries exclusively draining the Himalaya, provides a semi-actualistic key to be used, in conjunction with complementary provenance datasets and geological information, to reconstruct changes in paleodrainage and unravel the relationship between climatic and tectonic forces that controlled the erosional evolution of the western Himalayan-Karakorum orogen in space and time.

A number of hydrocarbon discoveries have been made recently in the Flemish Pass Basin and Central Ridge, offshore Newfoundland, Canada, but there is only limited geological information available. The primary goal of this study was to determine the sedimentary provenance and paleodrainage patterns of mudstones and sandstones from the Upper Jurassic Rankin Formation, including the Upper and Lower Kimmeridgian Source Rock (organic-rich shale) members and Upper and Lower Tempest Sandstone Member reservoirs, in this area. A combination of heavy mineral analysis, whole-rock geochemistry and detrital zircon U-Pb geochronology was determined from cores and cuttings from four offshore wells in an attempt to decipher provenance. Detrital heavy minerals in 20 cuttings samples from the studied geologic units are dominated by either rutile + zircon + apatite ± chromite or rutile + apatite + tourmaline, with minor zircon, indicating diverse source lithologies. Whole rock Zr-Th-Sc trends suggest significant zircon recycling in both mudstones and sandstones. Detrital zircon U-Pb ages were determined in two mudstone and four sandstone samples from the four wells. Five major U-Pb age groups of grains were found: A Late Jurassic group that represents an unknown source of syn-sedimentary magmatism, a Permian–Carboniferous age group which is interpreted to be derived from Iberia, a Cambrian–Devonian group derived from the Central Mobile Belt of the Newfoundland–Ireland conjugate margin, and two older age groups (late Neoproterozoic and >1 Ga) linked to Avalonia. The Iberian detritus is abundant in the Central Ridge and southern Flemish Pass region and units containing sizable populations of these grains are interpreted to be derived from the east whereas units lacking this population are interpreted to be sourced from the northeast and possibly also the west. The Upper Tempest Sandstone contains Mesozoic zircons, which constrain the depositional age of this unit to be no older than Late Tithonian.

Abstract Detrital-zircon (DZ) U-Pb data show that Appalachian-affiliated sediment was transported to western Laurentia by the Carboniferous, yet additional DZ U-Pb data from the eastern United States suggest that sediment-routing systems were oriented south toward the Ouachita deepwater sink. Within this context, this study presents DZ U-Pb ages from the Lower Pennsylvanian Caseyville Formation of Illinois, and U-Pb ages and εHf values from the coeval Pottsville Formation of Alabama as well as sandstone petrographic data from the Caseyville Formation, the Pottsville Formation, and the Jackfork Group of the Ouachita Basin to document provenance, delineate drainage divides in the Appalachian foreland-basin system, and comment on the unlikelihood of transcontinental sediment routing from the eastern United States to western United States at this time. Two DZ U-Pb age distributions from quartz arenite sandstones of the Caseyville Formation display prominent ca. 1250–950 Ma, 1550–1300 Ma, 1800–1600 Ma, and 3500–3000 Ma ages, consistent with ultimate derivation from Grenville, Midcontinent granite–rhyolite, Yavapai–Mazatzal, and Superior provinces, as well as minor contributions from ca. 500–400 Ma and 2000–1800 Ma grains. Two DZ U-Pb age distributions from sublitharenite sandstones of the Pottsville Formation display prominent ca. 500–400 Ma, 1250–950 Ma, 1550–1300 Ma, and 1800–1600 Ma ages, consistent with ultimate derivation from Appalachian, Grenville, Midcontinent granite–rhyolite, and Yavapai–Mazatzal provinces, as well as minor contributions from ca. 2000–1800 Ma and 3500–3000 Ma grains. The Pottsville Formation samples demonstrate a greater percentage of Appalachian and Grenville ages relative to the Caseyville Formation samples, whereas the Caseyville Formation samples have elevated Yavapai–Mazatzal and Superior percentages relative to the Pottsville. We interpret these differences to suggest parallel fluvial systems in the foredeep and back-bulge depozones of the Appalachian foreland-basin system. Like DZ studies of modern deep-sea fans that demonstrate an affinity to feeder fluvial systems, this study demonstrates fidelity between endmember segments of ancient fluvial-to-deepwater systems. Multidimensional scaling (MDS) analysis shows that DZ samples from the Pottsville and Caseyville formations cluster with deepwater Jackfork Group samples, and we infer a source-to-sink relationship from these two distinct source areas to the Ouachita terminal sink. One example of large-scale inclined strata thickness from the Caseyville Formation also suggests a drainage basin area of > 105 km2. Contextualized with these observations, we suggest that the foredeep and backbulge depozones of the Appalachian foreland-basin system steered distinct Early Pennsylvanian rivers across emergent continental shelves during periods of low sea-level, which discharged to distinct slope canyons and sourced > 100-km-long deep-sea fans. Clearly circumscribed, southward- or southwestward-oriented paleodrainage areas provide a template of the Appalachian foreland-basin system, and as such the central and southern Appalachians were an unlikely source for the Appalachian signature observed in the western United States at this time.

The High Atlas is an orogenic system resulting from the Cenozoic-Recent tectonic inversion of Triassic-Jurassic rift systems. Its present setting derives from a long and complex tectono-sedimentary evolution related to the Early Mesozoic opening of the Atlantic Ocean (pre-orogenic period) and, then, to the Cenozoic convergence between the African and European plates which led to a full tectonic inversion. The WSW-ENE trending chain is bounded by the North Atlas Fault to the north and the South Atlas Fault to the south, that represented the master faults of the rifted basins during the pre-orogenic period, then reactivated in inversion during the orogenic period. Early Jurassic syn-rift carbonate platforms, related to a marine ingression, were replaced in the Middle Jurassic-Late Cretaceous by post-rift fluvial and lacustrine environments. The related continental successions, regionally known as Couches Rouges, are not unanimously interpreted in the frame of the tectono-sedimentary evolution of the High Atlas. According to some authors they record localized early compressive-transpressive stages of deformation, others refer them to a period of tectonic quiescence. This study illustrates a revised stratigraphy, facies analyses and paleodrainage reconstruction of the Guettioua (Bathonian) and Jbel Sidal Formations (Barremian), that represents the fluvial units of the Couches Rouges, outcropping at the core of several syncline basins throughout the Central High Atlas. The aim is to understand if there was a tectonic forcing on the development of the Middle Jurassic – Lower Cretaceous fluvial systems. The sedimentological characters observed in the two fluvial formations suggest that they have been deposited by wide ephemeral fluvial systems, characterized by a high variable discharge. The reconstructed paleogeography, based on paleodrainage analysis, shows the fragmentation of the fluvial systems in several drainage basins, separated by local thresholds, uplifting during the sedimentation. Our reconstruction suggests that the post-rift fluvial systems were controlled by the presence of topographic highs in the area of the High Atlas of Marrakech, in the axial part of the chain and at its southern front, next to the South Atlas Fault. This conclusion, together with structural data and tectonic observations collected in some of the study areas, supports the idea that, from the Middle Jurassic, the Central High Atlas were affected by early compressive-transpressive stages of deformation.

ABSTRACT The Bighorn Basin (Wyoming, USA) contains some of the most extensively exposed and studied nonmarine early Paleogene strata in the world. Over a century of research has produced a highly resolved record of early Paleogene terrestrial climatic and biotic change as well as extensive documentation of spatiotemporal variability in basin-scale stratigraphy. The basin also offers the opportunity to integrate these data with the uplift and erosional history of the adjacent Laramide ranges. Herein, we provide a comprehensive provenance analysis of the early Paleogene Fort Union and Willwood Formations in the Bighorn Basin from paleocurrent measurements (n > 550 measurements), sandstone compositions (n = 76 thin sections), and U-Pb detrital zircon geochronology (n = 2631 new and compiled age determinations) obtained from fluvial sand bodies distributed widely across the basin. Broadly, we observed data consistent with (1) erosion of Mesozoic strata from the Bighorn and Owl Creek Mountains and transport into the eastern and southern basin; (2) erosion of Paleozoic sedimentary cover and crystalline basement from the Beartooth Mountains eastward into the northern Bighorn Basin; (3) conglomeratic fluxes of sediment from the Teton Range or Sevier fold-and-thrust belt to the southwestern Bighorn Basin; and (4) potential sediment provision to the basin via the Absaroka Basin that was ultimately derived from more distal sources in the Tobacco Root Mountains and Madison Range. Similar to previous studies, we found evidence for a system of transverse rivers contributing water and sediment to an axial river system that drained north into southern Montana during both the Paleocene and Eocene. Within our paleodrainage and provenance reconstruction, the basin-scale patterns in stratigraphy within the Fort Union and Willwood Formations appear to have been largely driven by catchment size and the lithologies eroded from the associated highlands. Mudrock-dominated strata in the eastern and southeastern Bighorn Basin were caused by comparably smaller catchment areas and the finer-grained siliciclastic strata eroded from nearby ranges. The conglomeratic and sand-dominated strata of the southwestern area of the Bighorn Basin were caused by large, braided fluvial systems with catchments that extended into the Sevier thrust belt, where more resistant source lithologies, including Neoproterozoic quartzites, were eroded. The northernmost early Paleogene strata represent the coalescence of these fluvial systems as well as rivers and catchments that extended into southwestern Montana that contained more resistant, crystalline lithologies. These factors generated the thick, laterally extensive fluvial sand bodies common in that area of the basin. When combined with provenance patterns in adjacent Laramide basins, our data indicate asymmetric unroofing histories on either side of the Bighorn and Owl Creek Mountains. The Powder River Basin to the east of the Bighorn Mountains displays a clear Precambrian crystalline provenance, and the Wind River Basin to the south of the Owl Creek Mountains displays provenance similarities to Lower Paleozoic strata, in contrast to provenance in the Bighorn Basin, which indicates less substantial unroofing. We infer that the differing unroofing histories are due to the dominant vergence direction of the underlying basement reverse faults. Overall, this provenance pattern persisted until ca. 50 Ma, when more proximal igneous and volcaniclastic units associated with the Absaroka and Challis volcanics became major sediment sources and the Idaho River system became the dominant transport system in the area.