The Ikka Project is an multinational, multidisciplinary group studying ikaite and in particular the remarkable submarine columns formed from ikaite found growing on the bed of Ikka Fjord southwest Greenland. In Ikka Fjord ikaite columns up to 20m high are found growing over submarine springs over a 2km stretch of the fjordbed. Over 700 such columns have been mapped in Ikka fjord and this area has been named 'The Ikka Column Garden' by the Ikka Project.
The Ikka Project is a group of scientists from a number of institutions, namely: The Geological Institute, The Botanical Institute and The Zoological Museum of the University of Copenhagen, Imperial College of Science, Technology and Medicine, London and The School of Earth and Ocean Sciences, University of Victoria, BC, Canada.
This Web page concentrates on the research activities of the geologists involved with The Project who have been engaged in:
Being a geochemical precipitate, understanding the formation of ikaite in Ikka Fjord means understanding the chemistry of its formation. Towards this goal a programme of sampling, geochemical analysis and laboratory modelling has been designed and implemented. During three field seasons water and rock samples have been collected from all the different elements involved within the environemnt of the fjord. A particular problem has been the tapping of pure samples of the waters leaking from the columns. The tapping was performed by scientific divers, led by Uffe Wilken, who had to develop a process of tapping the water from the columns without contamination from the surrounding seawater. (before and after images).
Early attempts involved simply sawing the tip of an actively growing column and then tying an empty bag over the stump. After a few days the sawn columns showed signs of regeneration as fresh ikaite began to grow on the stump. This growth was monitored and after measured after three week and then again after 13 months. The measured growth after 13 months was 0.5 metres, which despite the fact that growth had been artificially stimulated by sawing, is never the less an extremely rapid geological process.
The rock and water samples have been analysed in order to determine their geochemical parameters, establish their origins and relate them to the formation of the ikaite columns. Early results indicate that the water leaking from the columns is meteoric in origin and showed signs of enrichment in the chemicals necessary for ikaite formation during its passage through the Grønnedal-Ika Complex (Emeleus, 1964).
Work on the specimens collected in the field is being complemented by studies in the laboratory aimed at growing ikaite from solutions similar to those encounted in Ikka fjord. This natural recipe for ikaite is then quantitatively modelled and the the concentrations of the components varied to determine the roles and significance of each.
In order to establish how extensive the ikaite deposits are in Ikka Fjord and to begin to put them into their local environmental context, Ikka Fjord has been mapped in detail. This mapping program has included:
Direct access to the fjord bed is possible by divers enabling the collection of water and ikaite specimens, but the limited visibility and time available during such diving excursions makes mapping by direct means impossible. Thus three remote sensing geophysical survey techniques were employed to map the locality, namely: an echo sounder, a 'bottom imaging' side-scan sonar survey, and a shallow seismic 'pinger' survey. Careful attention to positional accuracy was required and so satellite navigation using a Differential Global Positioning System was used.
The bathymetry was mapped from a hybrid of data collected during all of the geophysical surveys. This data was then gridded and contoured using geostatistical techniques.
The principle mapping tool of the fjordbed morphology has been a side-scan sonar device towed behind a survey vessel. Nearly 700 columns were mapped by side-scan sonar which shows that the columns occur in lines, clusters and in complete isolation giving conflicting clues as to the controls over their distribution.
The temperature and salinity mapping were conducted using a dip meter, which is a probe lowered into the water and measurements are made as it is retrieved. The tips of the ikaite columns in Ikka Fjord show a fantastic variety of shapes and it seems probable that the crests and spires of the ikaite columns are features associated with temperature and salinity variations and the winter ice that covers the fjord from October to May.
The geomorphology of Ikka Fjord and its surrounding environment is studied using aerial photographs and fieldwork. The geomorphologists are trying to elucidate the glacial history of the fjord to determine how long the right conditions might have existed within the fjord under which the columns could develop. Additionally these geomorphoplogical studies are also adding an extra piece to the glacial history of Greenland by providing new data on the conditions in southern Greenland since the last Ice Age.
The development of ikaite columns over springs in Ikka Fjord is giving scientists a unique chance to see where, how and how much groundwater leaks into the sea from submerged aquifers. The water leaking out of the ikaite columns is of meteoric origin, i.e. it originally fell as rain and snow on the hills surrounding the fjord. By modelling the water pathways through the rocks forming the hills around Ikka Fjord it is possible to identify which rocks are contributing to the chemistry of the springs and ultimately to the ikaite columns themselves. The modelling is performed using a computer and requires a series of parameters to be measured in the field and laboratory.
From the studies outlined above it is now possible to begin to explain the formation of ikaite in Ikka Fjord. Plotting the ikaite columns on the bathymetry map shows how the columns are distributed about the fjordbed. Columns develop immediately beyond the shallow waters of a delta developing from the top of the fjord. They are then found continuously along the axis of the fjord, until coming to an abrupt stop against the regional fault line that bisects the fjord. The formation of ikaite columns is wholly contained within the outcrop of a volcanic intrusion known as the Grønnedal-Ika Complex.
Ikaite precipitates from mixing of seawater and ground water when they mix at the tip of a column. The reaction is that between carbonate and bicarbonate ions in the springs water and calcium in the seawater. Low temperatures in the fjord and a high phosphate concentration in the spring water favours the formation of ikaite, the phosphate acting as an inhibitor to calcite formation which is the normal precipitate expected in such a system. Readers can find a more detailed account in our recent article in Nature(Buchardt, et al.., 1997).
The Ikka Project has been helped and supported by many organisations to which we are extremely grateful. In particular would like to thank the following organizations:
Buchardt, B., Düwel, L., Kristiansen, A., Pedersen, G. H., Stockmann, G., Thorbjørn, L., Westergaard. D., 1996. En naturskabt søjlehave I Ikkafjorden I Sydvestgrønland. Naturens Verden, 250. 241-250.
Buchardt, B, Seaman, P. G., Düwel, L., Kristiansen, R. M., Kristiansen, A., Pedersen, G. H., Stockmann, G., Thorbjørn, L., Vous, M., Whiticar, M. J., & Wilken, U., 1997. Submarine columns of ikaite tufa. Nature. November 13. 390 issue number 6656.
Emeleus, C.H. 1964. The Grønnedal-Ika alkaline complex, South Greenland. The structure and geological history of the complex. Grønlands Geologiske Undersøgelse. Bulletin Number 45. Reprinted from Meddelelser om Grønland, Bd. 172, Number 3. 74 pages.
Pauly, H., 1963b. Ikaite - nyt mineral der danner skaer. Naturens Verden, June 1963. 168 - 171 & 186-192.
Seaman, P. G., 1998. Ikaite formation in a fjord environment with special reference to Ikka fjord. Unpublished Ph. D. thesis. University of London. 258 pages.
Fish, J. P., & Carr, H. A, 1996. Acoustics and Sonar. Excerpts from the side scan training courses at the Marine Group. Woods Hole Oceanographic Institution Web Page. USGS. http://www.marine-group.com/acoustic.htm
This Webpage has been designed and written by:
Dr. P Seaman: PaulS@geo.geol.ku.dk
Dr. B. Buchardt: http://trophy.geol.ku.dk/staff/buchardt/buchardt.html
