Thermal demagnetizer.
Thermal demagnetizer.

Introduction

GeoSphere Austria (former ZAMG) has a long tradition in geomagnetic field research providing systematic measurements since its foundation in 1851. With the beginning of 2014 the newly constructed Conrad Observatory provides a unique infrastructure for the observation of geomagnetic field variations, including a paleomagnetic laboratory in order to extend the modern and historical measurement series further back into the past.

Research activities

The main research activities are focused on the reconstruction of the ancient geomagnetic field behavior on different timescales. Therefore, archeological and geologic archives, which have acquired a thermoremanent magnetization in the past, are sampled and then investigated in the laboratory. Archeomagnetic studies enable the refining of secular variation over the last millennia in Central Europe providing reference curves for archeomagnetic dating. Furthermore, there is a strong focus in our research group on global geomagnetic field modelling based on available data compilations and the newly acquired field records. Measurement campaigns aiming at geological timescales are performed on volcanic rocks in order to study geomagnetic field reversals, especially absolute paleointensities during polarity transitions.

Equipment

The scientific equipment at laboratory comprises basic field equipment (e.g. orientation equipment), as well as archeo- and paleomagnetic measurement systems:

  • AGICO spinner magnetometer JR6A: Measurements of remanent magnetization.
  • MMTD-DSC: Thermal demagnetizer.
  • ASC D-2000 AF-demagnetizer: AF demagnetization and ARM acquisition.
  • Susceptibility measurement systems Bartington MS2B LF/HF: Measurements of bulk susceptibility.
  • MMPM 10 pulse magnetizer: IRM acquisition.

These instruments allow the state-of-the-art, high quality evaluation of the remanent magnetization and, hence, the determination of ancient field directions and intensities. Furthermore, effects of anisotropy and cooling rate dependence can be estimated as well as basic rock magnetic properties.

Outreach

The observatory offers a free online accessible database called HISTMAG, to which newly acquired archeomagnetic site-level data along with all necessary meta information are regularly uploaded. These records are also provided to other data compilations (e.g. GEOMAGIA50), while measurement raw data from published studies are provided in a github repository (https://github.com/PaleoInt).

The outreach activities comprise presentation of laboratory projects at major and specialized scientific meetings as well as publications in peer-reviewed international journals. Furthermore, communication activities aimed at non-specialized broad audiences (e.g. open house day, long night of research) are regularly performed for providing knowledge about the the Earth’s magnetic field behavior. This includes also consultation of national media for paleo- and geomagnetic issues.