During this 7 week scientific mission I learned all about geophysical and geological data acquisition. Refraction and reflection seismic data, gravity, magnetics, bathymetry, heat flow, dredging and the use of AUV... all these techniques were used to investigate the onset of back-arc spreading in one of the most active regions on earth: the Lau Basin. The expedition was a collaboration between GEOMAR and BGR.
Blog series: ARCHIMEDES-I blog
An escape of winter through embarking another a scientific cruise on the Mediterranean Sea? Yes please! With again the objective of geophysical data acquisition (think of magnetic data, bathymetry, seismic data etc.) I embarked on the German RV Maria S Merian MSM71 in the Ligurian Sea. Assembling and disassembling OBS stations as well as being introduced to the processing of both reflection and refraction seismic data was part of the job. The cruise was in collaboration with GEOMAR.
During the summer of 2017 I had the opportunity to join a scientific cruise to Indian Ocean with the objective of geophysical data acquisition (think of magnetic data, bathymetry, seismic data etc.) I was part of the OBS-team which meant assembling and disassembling the OBS stations as well as being introduced to the processing of both reflection and refraction seismic data. The cruise was on the German Research Vessel Sonne in collaboration with the Alfred Wegner Institute in Germany and the University of Bremerhaven.
Rheological inhomogeneities occur at all different scales. To see how they respond to extensional forces, I built 3D analogue models at lithosphere scale. Silicon-putty and sand layers are scaled to the continental crust and the mechanically strong mantle. To show how to make such a model I have prepared a short movie.
Publication: Beniest et al., 2018
The Ammer River Section in southern Germany is a beautiful succession of marls, coastal sediments and conglomerates. These lihtologies are the more proximal (slope) equivalents of the distal, organic rich shales that formed during the anoxic event around the Eocene-Oligocene Transition (EOT). As part of the PhD project of Annique van der boon we sampled the section for an integrated paleomagnetic and stratigraphic study. The transition from slope to shelf sediments (comprising the EOT) is dated at a. 33.2 Ma.
Poster presentation EGU 2017: Van der Boon et al., 2017
Publication: Van Der Boon et al., 2018
The conjugate margins of the Central Segment of the South Atlantic are a-symmetric and have different geological histories. This segment specifically has been influenced by the presence of the Tristan Plume. With the use of thermo-mechanical models I have tested the importance of the pre-rift location of the mantle plume with respect to lateral rheological differences in the lithosphere. The "classical" rift-to-break-up evolution is only one form of continental break-up. The break-up axis might also develop at a large distance from the plume-impingement point or laterally off-set to this point. The latter case can explain asymmetry in conjugate margin formation even in the early post-rift phase in e.g. the South Atlantic.
Publication: Beniest et al., 2017a , Beniest et al., 2017b
An old seismic database (acquisition in the 70s) was digitized and interpreted in terms of seismic stratigraphy and structural geology. The hypothesis investigates was to identify the extensional phases the system had suffered. Seismic stratigraphy was accompanied with a stratigraphic analysis of wells and onshore stratigraphy. Two extensional pulses were identified: one during the Eocene that only affected the northern Aegean region, and a second one during the Miocene that can be observed in all the Neogene basins in the Aegean Sea.
Publication: Beniest et al., 2016
The AMED (Actions-Marges Mediterrannee) cruise organized by IFREMER, Brest, France left for four weeks in September 2013 to the Gulf of Lyon, southern France, to acquire high resolution seismic data, bathymetry and shallow drilling. I worked with a chirp system to process very shallow depth signals (max 10-20 m).
Summary (in french): AMED - IFREMER
The Medvednica Mountains north of Zagreb are part of the Inner Dinarides. They consist of lowgrade metamorphic rocks, covered by Miocene sediments. The aim of this project was to look for kinematic indicators to investigate the evolution of the Medvednica Mountains from orogenic build-up to exhumation. Besides several shortening phases, the Medvednica Mountains have suffered two important extensional phases, one during the Late Cretaceous and a second during the Miocene.
Publication: Van Gelder, et al., 2015
MSc Thesis: Beniest, 2013
Every year the AAPG organizes an international competition where a delegation of students from universities all around the world compete. Every team receives an industrial database including well-log data, seismic data and some geological background. Ten weeks of intensely analyzing should give the teams enough time to convince a jury that the block they worked on should be explored or not.
The Fennoscandian shield covers large parts of Scandinavia, including northern Finland. These 3.4-1.9 Ga old rocks host mineral occurrences such as gold, copper and nickel. I got the chance to work with a professional exploration team in Lapand, northern Finland where we did fieldwork, geotechnical logging and modelling of orebodies.
Video: STEP Anglo American
As an intern I went to Oman where I worked on the mineral occurrences in the country at the GUTech in Muscat. Part of the work included organizing field works outcropping mineral deposits, but also visits to active extraction mines.
For a structural geological/petrological master course we went to the Nevado Filabrides mountains in southern Spain. Two road-sections around the area of Lubrin provided us with structural and petrological information about the tectonic history of the area. Our main goal was to identify if there were ophiolitic remnants in the area. Hence, we had to think in terms of protolith to figure out if all the parts of an ophiolitic sequence were there. Eight different members were investigated after which we concluded there was enough evidence for an ophiolitic sequence to be present.
The beautiful Lower Jurassic marine sedimentary section along the southern shores of the bay of Bristol was samples for two weeks. Close to the villages of East Quantoxhead and St. Audries Bay, the section is accessible. We took 403 samples that have been a analyzed for paleomagnetic purposes at the Paleomagnetic Lab Fort Hoofddijk, Utrecht University. The interpretation of the paleomagnetic section is based on stable magnetic carrier. Both the Triassic-Jurassic boundary and the Hettangian-Sinumerian boundary can be found in this section.
Publication: Hüsing, S.K. et al. 2014