Geological investigation of high-Arctic fjord-valleys
Top image: The Zackenberg River Delta (northeast Greenland). Photo: Graham Gilbert/UNIS
Graham Gilbert has studied fjord-valleys in the high Arctic and investigated sedimentary characteristics and permafrost development. Gilbert will defend his PhD thesis Wednesday 17 January at UNIS.
11 January 2018
Press release from the University of Bergen and the University Centre in Svalbard (UNIS)
Fjord-valleys, as sediment-filled palaeofjords, are characteristic of formerly glaciated mountainous coastal areas. High-Arctic fjord-valleys commonly host permafrost, but are poorly accessible and hence have drawn relatively little research.
The aim of this study is to investigate the sedimentary characteristics and pattern of ground-ice development of the Adventdalen fjord-valley (Svalbard) and the Zackenberg fjord-valley (northeast Greenland) by using the integrated methods of cryostratigraphy, clastic sedimentology, sequence stratigraphy, geomorphology and geochronology.
These areas were stripped of sedimentary cover during the Last Glacial Maximum (approximately 15000 years ago). Mud-dominated glaciomarine sedimentation occurred in the fjord during the early Holocene, when the tidewater glacier retreated rapidly by calving. A fjord-head Gilbert-type delta prograded into the fjord once its post-glacial shoreline was established. The delta advance was affected by glacioisostatic sea-level fall, when fluvial incision resulted in raised delta-plain terraces. Permafrost has since formed in these deposits. Ground ice structures indicate that permafrost is primarily epigenetic, formed in sediments gradually emerged above the falling relative sea level. Ice-rich, syngenetic permafrost is found in the top few meter of sediment and formed within the raised delta-plain terraces hosting aeolian sedimentation.
These study areas exemplify the sedimentary infilling and permafrost development history of high-Arctic fjords where the post-Weichselian deglaciation shoreline was established. These case studies may serve as potential analogues for other high-Arctic fjord-valleys with a similar palaeogeographic history of the last glaciation−deglaciation cycle.
Graham Gilbert will defend his thesis entitled “Cryostratigraphy and sedimentology of high-Arctic fjord-valleys” on Wednesday 17 January at 13:15. He will give a trial lecture entitled: “The temperature regime of permafrost in the light of climate change” at 10:15 the same day. Both lectures will take place in Lassegrotta, UNIS, Svalbard Science Centre.
The committee consists of Professor Jan Piotrowski (Aarhus University, Denmark) Professor Michel Allard (Université Laval, Canada), and Professor Atle Nesje (UiB). The disputation will be led by Associate Professor Marius Jonassen (UNIS).
Graham Gilbert comes from Canada and obtained his Bachelor’s degree from the Carleton University in Ottawa (2012) and his Master’s degree on permafrost and sedimentology from the University of Oslo (2014). He has been employed as a PhD candidate at UNIS since 2014.