Search results for "Sequence Stratigraphy"

Succession et remplacements de communautés à brachiopodes en régime de sédimentation discontinue (Jurassique Moyen, Bourgogne, France)

1993

Abstract Sequence stratigraphy throws a new and seminal light on the fossil record and helps in determining the respective role played by external control (community replacement) and internal control (paleoecological succession) in the temporal “train” of marine benthic paleocommunities. Five brachiopod-dominated communities (C1–C5) are recognized and their temporal “train” described, during the uppermost Bathonian-lower Callovian interval in Burgundy. The first series (C1–C3) exhibits a trend interpreted as a paleoecological succession and the next two (C3–C4, C4–C5) as community replacements. Within the scope of sequence stratigraphy, the paleoecological succession comes at the end of a t…

Facies and facies association of the siliciclastic Brak River and carbonate Gemsbok formations in the Lower Ugab River valley, Namibia, W. Africa

2007

Abstract The Neoproterozoic Zerrissene Turbidite Complex of central-western Namibia comprises five turbiditic units. From the base to the top they are the Zebraputs Formation (greywacke and pelite), Brandberg West Formation (marble and pelite), Brak River Formation (greywacke and pelite with dropstones), Gemsbok River Formation (marble and pelite) and Amis River Formation (greywacke and pelites with rare carbonates and quartz-wacke). In the Lower Ugab River valley, five siliciclastic facies were recognised in the Brak River Formation. These are massive and laminated sandstones, classical turbidites (thick- and thin-bedded), mudrock, rare conglomerate and breccia. For the carbonate Gemsbok R…

Refitting lithic laminar fragments to assess Palaeolithic sequences: The case of Cova de les Cendres (Teulada-Moraira, Alicante, Spain)

2020

Abstract The integrity of the different levels that form a sequence and the formation processes of the archaeological deposit must be assessed as a previous step to the construction of behavioural, cultural and evolutionary interpretations. This is especially relevant when dealing with long sequences and cultural evolution constructed on them, as is the case in the research on Upper Palaeolithic. Lithic taphonomy provides insight into these issues and refitting is one of its powerful tools. This approach has been applied to the Aurignacian, Gravettian and Solutrean levels of Cova de les Cendres (Teulada-Moraira, Alicante, Spain), where fracture refits of laminar fragments –including blades,…

Taphonomic sequences—A new tool for sequence stratigraphy

2002

The Middle-Upper Jurassic boundary in western Europe is characterized by extensive condensed sections containing authigenic minerals together with abundant and varied fossils, both reworked and not reworked. We have analyzed ammonite shells and chronologically ordered taphonomic events in a taphonomic sequence extending from the time the dead organism settled on the seafloor to the time it became permanently incorporated in the sediment. Three types of taphonomic sequence are recognized; they are characteristic of (1) sedimentation in depositional environments having little and only occasional hydrodynamic activity (coinciding with periods of increasing accommodation), (2) sedimentation dur…

Plio-Pleistocene geological evolution of the northern Sicily continental margin (southern Tyrrhenian Sea): new insights from high-resolution, multi-e…

2003

High-resolution seismic profiles were acquired in the north Sicily offshore region with an innovative, multi-tip sparker array which lacks ringing and has a base frequency around 600 Hz. The new data, combined with published data, suggest that intra-slope and extensional basins formed as a consequence of the late Miocene (?)–early Pliocene shortening and thrusting, and the middle (?)–late Pliocene continental rifting affecting the internal side of the Sicilian-Maghrebian chain. Early (?) Pleistocene to Holocene high-amplitude and high-frequency sea-level changes resulted in repeated sub-aerial exposure and flooding of the shelf, and the deposition of cyclically arranged hemipelagic and shel…

Lowstand carbonates, highstand sandstones?

2003

The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene …

Sequence stratigraphy of the Late Neogene – Quaternary deposits in the Egadi Islands offshore (NW Sicily)

2008

The capability of Rare Earth Elements geochemistry to interpret complex archaeological stratigraphy

2019

Abstract In this study rare earth elements (REE) signatures (REE ratios, cerium and europium anomalies) are applied to a complex soil stratigraphic sequence from the site of Konso, Ethiopia, with the aim of determining whether REE can distinguish the strata observed in the field. Forty soil samples were taken from a depositional sequence that includes overlapping human induced and ‘natural’ erosional and depositional processes. The samples were analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine trace elements and REE, with concentrations of major elements determined using X-ray fluorescence (XRF). Cluster Analyses (CA) were used to observe differences between str…

The owl that never left! Taphonomy of Earlier Stone Age small mammal assemblages from Wonderwerk Cave (South Africa)

2022

Wonderwerk Cave, in South Africa, is an exceptional site that has yielded a large collection of small mammal fossils in a stratigraphic sequence reaching back ca. 2 million years. Taphonomic studies undertaken to date, show that Tytonidae (likely Tyto alba) was the dominant predator during the Earlier Stone Age. They produced masses of pellets that formed a dense carpet-like surface that covered the cave floor at intervals throughout the sequence. This paper compares the taphonomic signatures of five different Earlier Stone Age small mammal assemblages from Wonderwerk Cave, including assemblages not studied before, as well as a modern pellet assemblage collected from inside the cave. These …

Sequence stratigraphy of a mesozoic carbonate platform-to-basin system in Western sicily

2009

Abstract Sequence stratigraphic studies of the Triassic through Paleogene carbonate successions of platform, slope and basin in western Sicily (Palermo and Termini Imerese Mountains) have identified a sedimentary cyclicity mostly caused by relative oscillations of sea level. The stratigraphic successions of the Imerese and Panormide palaeogeographic domains of the southern Tethyan continental margin were studied with physical-stratigraphy and facies analysis to reconstruct the sedimentary evolution of this platform-to-basin system. The Imerese Basin is characterized by a carbonate and siliceous-calcareous succession, 1200–1400m thick, Late Triassic to Eocene in age. The strata display a typ…