Andreas Wetzel

Andreas Wetzel
University of Basel | UNIBAS · Department of Environmental Sciences

About

208
Publications
84,188
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,973
Citations
Citations since 2017
43 Research Items
2367 Citations
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400

Publications

Publications (208)
Article
Full-text available
The mud-dominated part of the basal Vaca Muerta Formation in the central Neuquén Basin accumulated mainly under dysoxic conditions as indicated by the absence of both fine lamination and large burrows, typical of anoxic and oxic conditions, respectively. Event beds and large, strata-bound concretions preserving a nearly uncompacted sediment fabric...
Article
The Silurian Sharawra Member (middle to late Llandoverian) in Saudi Arabia exhibits unique surface traces with exceptional preservation: Seven small, wing-shaped traces occur on a sandstone slab showing well-defined hummocky cross-stratification having a few decimeters wavelength being covered by a thin mud layer. These traces are preserved as conc...
Article
Full-text available
Zusammenfassung: Aus dem Belchen-Member (Rhät) der spättriassichen Klettgau-Formation wer-den drei Handstücke beschrieben, die Lebensspuren von Asterozoen enthalten. Zwei Stücke stam-men von der Typus-Lokalität am Chilchzimmersattel (Belchen). Auf ihnen konnte Asteriacites lum-bricalis bzw. Asteriacites cf. stelliformis nachgewiesen werden. Letzter...
Article
Full-text available
The mechanisms that govern the vertical growth of seep carbonates were deciphered by studying the sedimentary architecture of a 15 m thick, 8 m wide column of limestone encased in deep-water marl in the middle Callovian interval of the Terres Noires Formation in the SE France Basin. The limestone body, also called “pseudobioherm”, records intense b...
Article
Full-text available
Radish concretions exhibit a typical columnar to pear-shaped, stipe downward geometry. In Middle Jurassic mudrock in south-west Germany, radish concretions started to form around an iron-sulphide lined tube by pervasive cementation constituting an ellipsoidal parent domain in uncompacted sediment at burial depths of ≤ 5 to 8 m as recorded by 75 to...
Article
Full-text available
At a Pliocene methane seep site in Taiwan, an about half meter-long dolomitic concretion hosting a lucinid bivalve Anodontia goliath, ∼11 cm in diameter reveals the impact of chemosymbiotic bivalves on fluid migration through the shallow sediment. The concretion consists of a central channel filled with sparite and varying amounts of brecciated mat...
Article
Full-text available
Description of lithostratigraphy and biostratigraphy of the Opalinuston Formation at the type locality
Article
Considering the evolution of aeolian to marine transitions for the geological record, either catastrophic or gradual transgressive scenarios showing high or low rates of coastal migration have been proposed. A critical evaluation of modern analogues suggests that a catastrophic transgression shares many characteristics with Holocene transgressions,...
Article
In the Lower Cretaceous McMurray Formation (Alberta, Canada), many intervals of intensely bioturbated (Bioturbation Index = 5–6) fine-grained sediments are characterized by high gamma-ray (GR) readings. Several methods, including sedimentary facies analysis, thin-section petrography, handheld spectral gamma-ray, portable X-ray fluorescence, X-ray d...
Article
Full-text available
During times of lowered sea level, Mekong River and Red River incised valleys into the ancient coastal plains of the exposed shelves of the western South China Sea. The deglacial fill history of the incised valley was investigated by seismic surveys and sediment cores. The channels mainly exhibit a low-sinuosity course, but some channel segments ar...
Preprint
Full-text available
We investigated the mechanisms that govern vertical growth of seep carbonates by studying the sedimentary architecture of a 15-m-thick, 8-m-diameter column of limestone encased in a deep-water marl succession in the Middle Callovian interval of the Terres Noires Formation in the SE France basin. The limestone body, a.k.a. pseudobioherm is character...
Article
Full-text available
The Holocene muddy infill of the valley incised by the ancient Red River during Pleistocene sea-level lowstand records a change from fluvial to estuarine and finally marine depositional conditions. Siphonichnus, a mainly vertical trace fossil produced by burrowing bivalves, documents otherwise unrecorded episodes of enhanced erosion, bypass and dep...
Article
Full-text available
The Toarcian - lower Callovian Los Molles Formation in the Chacay Melehue section (southern limb of Cordillera del Viento - Neuquén Basin) comprises offshore-shelf deposits and subordinately, channel-levee and lobe deposits produced by density currents. These deposits are characterized by two distinctive trace fossil suites: (1) Chondrites and Tric...
Article
Full-text available
The graphoglyptid trace fossil Paleodictyon, characterized by stratiform hexagonal meshes, typically occurs preserved at the base of deep-marine turbidites. There is, however, a growing number of occurrences of Paleodictyon in shallow-marine deposits as evidenced by new finds in the Eocene of Iran. The Paleodictyon-containing Asara Shale Member of...
Article
The Oligocene Lower Freshwater Molasse of Switzerland is host to spectacular outcrops of fluvial deposits. In distal areas of the Swiss Molasse Basin, deposits of a north-eastward draining meandering system are exposed. Combined sedimentologic and ichnologic observations in the Chli Sunnhalde and Roggwil quarries allow an improved understanding of...
Article
Full-text available
The reworking of a trace by a subsequently following organism represents a so-called sequorichnial behavior and leads to formation of a “burrowing highway”. Burrowing highways occur more frequently than assumed in the fossil record. Their ichnological and sedimentological meaning is elucidated by using the trace fossil Gyrochorte. Gyrochorte produc...
Article
The lower Maastrichtian deposits of the Mateur-Beja area in northern Tunisia are mainly composed of fine-grained marl and limestone alternations occasionally interbedded by coarse-grained calcarenites and gravel deposits. In the coarse-grained intervals sedimentary structures are indicative of storm-induced high-energy currents in an outer ramp to...
Article
Full-text available
The lower Maastrichtian deposits of the Mateur-Beja area in northern Tunisia are mainly composed of fine-grained marl and limestone alternations occasionally interbedded by coarse-grained calcarenites and gravel deposits. In the coarse-grained intervals sedimentary structures are indicative of storm-induced high-energy currents in an outer ramp to...
Article
The passive and active fill of burrows potentially stores information about sedimentary processes that are otherwise not preserved in the rock record. In recent years, abandoned passively-filled vertical burrows were introduced as “tubular tidalites” when their infilling displays rhythmic lamination reflecting a tidal signature. In the shallow-mari...
Article
Most stellate trace fossils of the ichnogenus Asteriacites are attributed to asterozoan producers in general and the majority is the result of the work of ophiuroids. The fossil record of asterozoans is scarce in South America, particularly for the Mesozoic. Asteriacites specimens found in shallow- to marginal-marine Lower Cretaceous (upper Hauteri...
Article
Full-text available
A new type of gas chimney exhibiting an unconventional linear planform is found. These chimneys are termed Linear Chimneys, which have been observed in 3-D seismic data offshore of Angola. Linear Chimneys occur parallel to adjacent faults, often within preferentially oriented tier-bound fault networks of diagenetic origin (also known as anisotropic...
Chapter
Full-text available
We suggest an alternative mechanism for the formation of chimneys; "apart from overpressured fluid (gas) creating new fractures, overpressured gas may also pass through, filling pre-existing sub-vertical cracks/fractures in the hanging wall bottoms along the main fault surface (see fig. 2 in Gaffney et al., 2007). Pre-existing vertical fractures in...
Conference Paper
Full-text available
El análisis icnológico de los afloramientos de la Formación Los Molles (Jurásico Inferior) en el área de la Cordillera del Viento permitió reconocer dos suites de trazas fósiles, una correspondiente a depósitos de offshore-plataforma, y otra a depósitos de albardones de canales generados por corrientes de densidad. Los depósitos de offshore-platafo...
Article
Environmental changes within a Neogene coastal dune system are recorded by endobenthic unioniform bivalves that lived in muddy or sandy interdune pond sediments. These bivalves were suspension-filter feeders that formed dense, almost monospecific communities in the wet-interdune deposits of the continental intervals of the Río Negro Formation (late...
Article
During the Early Jurassic (lasting ~ 27 Myr) only thin deposits (mostly ca. 30–50 m) of the Staffelegg Formation accumulated in wide parts of NW Switzerland while sea-level rise was in the range of ~ 60 m. Isopach and facies patterns provide clear evidence of differential subsidence while faults that formed in the basement during the late Palaeozoi...
Article
Full-text available
Pockmarks in Pliocene-Quaternary continental slope deposits offshore Angola show features related to: (1) fluid leakage craters that formed repeatedly, (2) authigenic methane-derived carbonates that indicate the (former) presence of hydrocarbons and (3) erosional–depositional structures that are clearly related to current activity. Depending on top...
Article
Full-text available
A new type of gas chimney exhibiting unconventional linear planform has been observed on 3D seismic data offshore Angola, and is termed Linear Chimneys. These chimneys occur in the shallow buried hemipelagic succession which was affected by syn-sedimentary remobilisation processes related to hydrocarbon migrations. Linear Chimneys are oriented para...
Presentation
Full-text available
This chapter highlights an alternative hypothesis of gas chimney formations in hanging walls, which can be caused by fluid migrations along pre-existing vertical fractures: "Apart from overpressured fluid (gas) creating new fractures, overpressured gas may also pass through, filling pre-existing sub-vertical cracks/fractures in the hanging wall bot...
Article
An uncommon trackway of a seabird consisting of impressions of the right foot accompanied at the left side at the supposed position of the foot only by holes was produced by a gull having two legs, but only one foot. Foot size and stride are typical of an adult herring gull. The stride is unequal between right-left and left-right impression by ∼15%...
Method
Detailed program & pre-registration form is available: https://fluid-venting-system.weebly.com/ias-field-trip-june-2018.html IAS field trip: SEISMIC-SCALE FLUID MIGRATION FEATURES IN A PASSIVE MARGIN SETTING OUTCROP ANALOGUES FROM THE MESOZOIC SE FRANCE BASIN
Presentation
Full-text available
http://fluid-venting-system.weebly.com/ias-field-trip-june-2018.html This field trip will take place in the SE France Basin, which is filled by up to 10 km-thick pile of Mesozoic sediments. These accumulated in a deep embayment that opened onto the divergent, then drifting northern margin of the Tethys Ocean. Several organic-rich intervals were dep...
Presentation
Full-text available
Introduction - 3 Days IAS Field Trip 12th -14th June 2018, Sisteron (Provence), France For more information please visit: http://fluid-venting-system.weebly.com/ias-field-trip-june-2018.html
Article
A first palynostratigraphic scheme of Upper Triassic deposits in northern Switzerland was established based on spore-pollen associations and dinoflagellate cyst records from the upper part of the Upper Triassic Klettgau Formation and the lower part of the Lower Jurassic Staffelegg Formation. Drill cores from the Adlerberg region (Basel Tabular Jura...
Article
Eocene oceanic red beds that formed in a well-oxygenated setting at low sedimentation rates below the calcite compensation depth are effectively barren of organic carbon in the present state. Recurrent distal low-erosive turbidites preserve the bioturbated zone underneath that documents seasonal and long-term fluctuating accumulation of considerabl...
Research
Full-text available
The work of SO-220 pursued a multidisciplinary approach. The continental shelf of the Gulf of Tonkin and its continental slope at the transition to the deep-sea areas in the South China Sea were surveyed by three teams from a biogeochemical (sub-project 1), physical oceanographic (sub-project 2) and coastal-marine geologic (sub-project 3) approach....
Article
Full-text available
The Gulf of Tonkin coastline migrated at an average rate of ca 60 m year⁻¹ landward during Holocene sea-level rise (20 to 8 ka). Due to a combination of rapid coastline migration and undersupply of sand, neither coastal barriers nor tidal sand bars developed at the mouth of the Red River incised valley. Only a 30 to 80 cm thick sandy interval forme...
Article
Full-text available
Tubulichnium rectum (Fischer-Ooster, 1858) is an oblique to horizontal, unbranched, blind ending tube having margins densely lined with ellipsoidal muddy pellets. It occurs in fine sandy to muddy, siliciclastic and marly deep-sea sediments mostly from Turonian to Eocene times. It was probably produced by “worm”-like organisms, which fed on organic-...
Chapter
Full-text available
The Mesozoic Marine Revolution (MMR) was a major evolutionary episode involving the large-scale restructuring of shallow-marine benthic communities and the rise to dominance of the Modern Evolutionary Fauna. Although the majority of studies published on the MMR have been based on the body-fossil record, the ichnologic record yields valuable insight...
Article
Full-text available
The Serbo-Macedonian Massif (SMM) represents a composite crystalline belt within the Eastern European Alpine orogen, outcropping from the Pannonian basin in the north to the Aegean Sea in the south. The central parts of this massif (south-eastern Serbia) consist of the medium- to high-grade Lower Complex and the low-grade Vlasina Unit. Outcrop- and...
Article
Full-text available
The sediments of late Anisian and Ladinian age in northern Switzerland, which were formerly named Upper Muschelkalk and Lower Keuper, mostly consist of carbonates. They accumulated in a transitional area between central parts of the Central European Epicontinental Basin and its margin towards the Vindelician Swell. Oolitic intervals imply the forme...
Article
In the context of the harmonisation of the Swiss lithostratigraphic scheme, the Late Ladinian to Early Norian Bänkerjoch Formation and the Norian to Rhaetian Klettgau Formation of northern Switzerland are formally defined. The Bänkerjoch Formation replaces the «Gipskeuper». Delimitation generally follows the traditional Swiss scheme with the onset...
Article
Full-text available
Trace fossils provide valuable palaeoenvironmental information in hemipelagic settings. This is particularly true in the case of Zoophycos, an easily recognizable trace fossil in core. At IODP site U1385, Zoophycos was found throughout an interval representing 1.5 Ma, covering 45 glacial–interglacial cycles mediated by obliquity (41 ka) and short-t...
Article
Surface trails of earthworms exhibit a similar pattern and geometrical arrangement at three different localities in southern, western, and central Europe and, hence, document distinct behavioral modes of the producers. Straight to slightly winding trails (gutters bounded by levees) are a record of normal behavior moving to a new habitat. Earthworms...
Article
The juxtaposition of the ALCAPA and Tisza–Dacia continental blocks, although one of the key issues in the evolution of the Carpathians, is not well known in terms of associated effects on the sedimentary systems during frontal foreland development. Most of the contact between ALCAPA and Tisza–Dacia being covered by post-tectonic deposits, these eff...
Article
Full-text available
The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural fie...
Conference Paper
Full-text available
Many different lithostratigraphic units are currently in use for the Upper Muschelkalk and the former Lower Keuper of northern Switzerland. They are mainly based on lithological characteristics or fossil content, such as Trochitenkalk, Coenothyrisbank or Mergelhorizont, or they were adopted from German units, for instance Grenzdolomit. In the conte...
Article
The Serbo-Macedonian Massif (SMM) represents a composite crystalline belt within the Eastern European Alpine orogen, outcropping from the Pannonian basin in the north, to the Aegean Sea in the south. The central parts of the massif (i.e. southeastern Serbia, southwestern Bulgaria, eastern Macedonia) consist of the medium- to high-grade Lower Comple...
Chapter
Full-text available
Trace fossils may store a sedimentary record that is not otherwise preserved due to living organisms actively filling their burrows with material from the sediment surface, or the passive filling of open burrows after their abandonment. The potential of burrow-fill to unravel the incomplete stratigraphic record, in shallow water as well as deeper s...
Article
Full-text available
A new sea-level record derived from coastal deposits of the South Vietnam shelf covers the deglacial sea-level history between 13.0 and 9.0 ka BP. This record reveals a relatively constant