Marine Geophysics
Faculty of Geosciences | FB5
Core Logging in the Lab and at Sea
Methods and instruments for sediment core logging
Team: Thomas Frederichs (lab manager), Christian Hilgenfeldt (system engineer), Liane Brück (lab technician), Heike Piero (data management), Tilo von Dobeneck (data processing)
Rooms: University of Bremen, GEO Building, Rooms 4140/0100

Techniques: Sediment physical properties such as magnetic susceptibility, electric conductivity, sound velocity, and color reflectance are controlled by sediment composition and fabric. With modern logging methods, these parameters can be measurement quantitatively, non-destructively and at high resolution on sediment cores and rock samples. They are of high practical value for the description, stratigraphy and correlation of sediment cores and their comparison with macnetic, seismic and geoelectric surveys on land and at sea. We have conducted routine core logging and imaging on board of research vessels and in our own core logging laboratory over the past 30 years and hold competence in reliable data acquisition, analytical and statistical data mining methods and sedimentological and paleooceanographic core log interpretations.

MSM39 shipboard core transect B from logging data

MARUM fast track Multi Sensor Core Logger (MSCL)
Team: Thomas Frederichs, Christian Hilgenfeldt, Liane Brück, Tilo von Dobeneck
Room: University of Bremen, GEO Building, Room 0100 and at sea

System: This fast-track Multi Sensor Core Logger has been designed for shipboard operation, constructed with MARUM funds, and successfully proven at sea. The stiff modular structure and the compact cable harness facilitate onboard installation. The system is presently equipped with Bartington loop sensors for full- and half-core magnetic susceptibility logging - optionally with 135mm bore (MS2C135) for 10-12cm thick cores or 80mm bore for 6-7cm thick cores and U-channels. The new control unit (MS3) reduces measuring time to 1-3 sec thereby doubling core throughput. The non-contact resistivity (NCR) sensor for porosity measurement now has digital, less noise-sensitive electronics. The innovative drivetrain with two toothed belt conveyors in V-setting allows to log changing core diameters (MEBO, GC, PC) without prior conversion, laser segment length and position control with sub-mm-precision, and bidirectional core transport enabling zero offset correction within segments. The new LabView control software autmates all required data processing steps (drift and core-end correction, deconvolution) and simplifies data control and organization.

MARUM fast track Multi Sensor Core Logger

GEOTEK Multi Sensor Core Logger with GEOSCAN II Linescanner
Team: Thomas Frederichs, Liane Brück, Christian Hilgenfeldt, Tilo von Dobeneck
Room: University of Bremen, GEO Building, Room 0100 and at sea

System: Our mobile GEOTEK Multi Sensor Core Logger (MSCL) is primarily operated on board of research vessels. It is equipped with a magnetic susceptibility coil sensor (Bartington MS2C, diameter 140 mm, effective resolution of 2 x 10E-6 SI) integrating over a core interval of ca. 8 cm. An additional non-contact resisitivity sensor (NCR) is taken to measure electric conductivity, from which sediment porosity and wet bulk density can be estimated. All individual segment logs are merged into a complete core log, where the immanent core-end signal reduction is compensated by an adapted correction function. The digital RGB line scan camera GEOSCAN II consisting of three 1024 pixel CCD line arrays obtains digital color photographs of the entire split cores surface. A specific image processing program connects the segment images while removing end-caps, cavities and other raw image disturbances prior to further image analysis (e.g. lightness, hue, color ratios).

Geotek Multi Sensor Core Logger onboard RV Sonne
GEOTEK MSCL web page

GEOTEK MSCL Manual

Split core logging system with Bartington magnetic susceptibility spot sensor
Team: Thomas Frederichs, Christian Hilgenfeldt, Liane Brück
Room: University of Bremen, GEO Building, Room 4140

System: Our stationary laboratory half-core logger is optimized for high-resolution, high-precision logging of magnetic susceptibility on archive halves, e.g. for the purposes of cyclostratigraphy, time series and facies analysis. The three-axis stepper motor drive makes it possible to automatically move the core half longitudinally and transversely and to lower and raise the Bartington point sensors used in a distance-controlled manner. The optional MS2F and MS2E sensors measure very close to the surface and achieve a much better spatial resolution than the ring sensors of the MSCL systems with half-value widths of approx. 3 cm and 1.5 cm respectively. Logging can be carried out in freely selectable mm steps for measurements on up to 1.5 m long half-cores and U-channels. Each measuring point on the core surface is supplemented by a subsequent air measurement in order to be able to dynamically correct the high temperature drift typical of sensors. This results in a measuring time of approx. 20 minutes for a 1 m long core segment with a measuring point distance of 1 cm.


Portable Spectrophotometers Konica Minolta CM-2600d
Team: Liane Brück, Tilo von Dobeneck
Room: University of Bremen, GEO Building, Room 4140

System: This spectrophotometer determines the diffuse reflectance of rock surfaces in the extended visible light spectrum of 360-740 nm (10 nm intervals) over area of 8 resp. 3 mm (Ø). The manual system is useful for the lithostratigraphic analysis of split cores and cube samples, in particular to measure the abundance of pigmented minerals such as hematite, goethite, coal, clay etc. A new endmember modelling technique for such data was developed by our group (Heslop et al. 2007) and used to detect dust and diagenetic layers in sediment cores.

Product catalogue Konica Minolta CM-2600d pdf-File (1.49 MB)

Technical specifications (Konica Minolta)

Heslop D., von Dobeneck T., Höcker M. (2007)
Using non-negative matrix factorization in the unmixing of diffuse reflectance spectra
Marine Geology, 241, 63 - 78
doi: 10.1016/j.margeo.2007.03.004


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