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Dr. Janis Thal

Archived Page

This web page has not been updated since the former colleague left MARUM.

 

Research interests

  1. Bathymetry
  2. Geologic mapping of the seafloor
  3. GIS applications
  4. Hydrothermal vents
  5. Marine geology
  6. Submarine volcanism
  7. Marine resources
 

Publications

  • Monien P, Lettmann KA, Monien D, Asendorf S, Wölfl A-C, Lim CH, Thal J, Schnetger B, Brumsack H-J (2014): Redox conditions and trace metal cycling in coastal sediments from the maritime Antarctic. Geochimica et Cosmochimica Acta 141, 26-44.
    | doi:10.1016/j.gca.2014.06.003 |
  • Thal J, Tivey M, Yoerger D, Jöns N, Bach W (2014): Geologic setting of PACManus hydrothermal area - High resolution mapping and in situ observations. Marine Geology 355, 98-114.
    | doi:10.1016/j.margeo.2014.05.011 |
  • Marcon Y, Sahling H, Borowski C, dos Santos Ferreira C, Thal J, Bohrmann, G (2013): Megafaunal distribution and assessment of total methane and sulfide consumption by mussel beds at Menez Gwen hydrothermal vent, based on geo-referenced photomosaics. Deep Sea Research Part I: Oceanographic Research Papers
    | doi:10.1016/j.dsr.2013.01.008 |
  • Bach W, Jöns N, Thal J, Reeves E, Breuer C, Shu L, Dubilier N, Borowski C, Meyerdierks A, Pejvac P, Brunner B, Müller I, Petersen S, Hourdez S, Schaen A, Koloa K, Jonda L, MARUM Quest 4000m team (2012): Interactions between fluids, minerals, and organisms in sulfur-dominated hydrothermal vents in the eastern Manus Basin, Papua New Guinea – A report from RV Sonne Cruise 216. InterRidge News 21, 31-34.
    | InterRidge Newsletter |

Posters & Talks

  • Thal, J. (2016): Marine Resources – Ore deposits and black smokers. SINGOFOS-Symposium (Invited talk).
  • Thal, J., Bach, W. Tivey, M., Yoerger, D.R. (2016): Subaqueous Cryptodome Eruption, Hydrothermal Activity and Related Seafloor Morphologies on the Andesitic North Su Volcano, Papua New-Guinea. SINOGFOS-Symposium, Shenzhen, China (Poster).
  • Thal, J., Bach, W., Tivey, M., Yoerger, D.R. (2013): Volcanic and hydrothermal activity of the North Su Volcano: New insights from repeated bathymetric surveys and ROV observations. AGU Meeting 2013, San Francisco, USA (Poster).
  • Thal, J., Bach, W., Tivey, M., Yoerger, D.R. (2011): High-resolution geologic mapping in the eastern Manus Basin. AGU, OS13A. Doing Fieldwork on the Deep Seafloor II Posters, San Francisco (Poster).

Expeditions

  • 03/2006: FS Meteor 67/2a - Caribbean Sea, Cristobal - Tampico,
    Chief scientist: Prof. G. Bohrmann (MARUM, University of Bremen)
  • 05/2008: FS Poseidon 366/1 Northwest African shelf, Las Palmas – Las Palmas,
    Chief scientist: PD Dr. Sabine Kasten (AWI Bremerhaven)
  • 08/2010: FS Poseidon 402 – Mid Atlantic, Ponta Delgada – Ponta Delgada,
    Chief scientist: Dr. Christian Borowski (Max Planck Institute Bremen)
  • 06-07/2011: FS Sonne 216 – Manus Basin, Townsville – Madang,
    Chief scientist: Prof. W. Bach (University of Bremen)
  • 04-05/2012: FS Maria S. Merian 20/5 – Mid Atlantic, Freeport – St. John’s
    Chief scientist: Prof. W. Bach (University of Bremen)

Ph. D. project

Systematic analysis of bathymetry combined with video recordings, rock analysis and temperature measurements produce comprehensive maps of the geological structures manifest on the seafloor. Detailed seafloor mapping is a necessity to combine fluid, rock and sediment samples as well as biologic studies. Bathymetry with state-of-the-art multibeam echosounders mounted on research vessels or AUVs enable, in combination with high-resolution video recordings from ROVs, an identification of meter-scale seafloor structures. Geographic information systems are used to handle the amount of data and to analyze systematics.

This thesis is based on two different locations:
PACManus is a hydrothermal active area in the eastern Manus Basin, an opening back-arc basin in Papua New Guinea. PACManus is situated in 1600-1800m water depth on a neo volcanic ridge (Pual Ridge) dominated by felsic volcanism.

North Su is an active strato volcano in the eastern Manus Basin. Black and white smoker hydrothermal activity exists near the summit as well as discharge sites of fluid, native sulfur.