CROSSING THE SCIENTIFIC AND TECHNOLOGICAL FRONTIER
FROM SOLID ROCK TO MAGMA
Magma is the last unexplored frontier of the Earth’s crust because it presents the greatest technological challenge.
Nevertheless, if we want to fully understand geothermal systems, volcanic eruptions, ore deposits, and the evolution of the Earth’s crust, we must go there. Following the discovery of magma at modest depth beneath Krafla Caldera, Iceland, an international coalition of scientists and engineers has been assembled to establish a long-term natural laboratory or ‘testbed’ to take full advantage of this important discovery — the Krafla Magma Testbed (KMT).
KRAFLA MAGMA TESTBED
The migrations of magma and fluid are the agents of mass and heat transfer within the crust and through to the earth’s surface. Magmas pool near the surface in volcanic systems and sampling the interface between the fluid-bearing or hydrothermal regime and the silicate melt-bearing or magmatic regime one of the great challenges in understanding Earth’s processes. Humans experience the effects of interactions at this interface as volcanic eruptions, geothermal energy, and chemical exchange forming ore deposits.
Geothermal drilling in the Krafla Caldera, Iceland, is provided by the government owned Icelandic company Landsvirkjun, one of the partners in this project. In 2009 the company serendipitously hit rhyolite magma at ~900°C at a depth of only 2100m. Heat removed through water circulation was at 450°C in a highly permeable zone at the magma-rock/fluid interface. Fragments of quenched glass and variably crystallized magma were recovered, but their contextual relationships were poorly constrained as the drilling was never set up for accurate sample recovery. However, this discovery proved that a well-designed project could penetrate this interface could rigorously test concepts of volcanic systems and produce results of enormous scientific, economic and social value.
We stand at the threshold of obtaining a new kind of knowledge about magma in Earth’s crust. The unexpected but successful encounters with rhyolite magma by geothermal drilling in Krafla Caldera, Iceland (see the video to the left) open the door to direct exploration of hydrothermal/magma coupling and the transition from solid rock to magma itself. For scientific drilling into this unexplored domain, there is literally no place on Earth better suited. Nowhere else has magma been encountered multiple times and controlled, and in a volcanic system about which so much is known in terms of geologic history, geophysical surveys, and monitoring, and three-dimensionally through numerous (40) existing boreholes.
Logistical and environmental considerations are as favorable as can be imagined: easy access, copious water supply, an already developed geothermal field so that the project’s incremental impact will be negligible, potential benefits to the local and regional community that transcend power generation, and a welcoming geothermal partner and host country. This is not to say that the undertaking lacks risks and the need for due diligence. But there are no “show-stoppers” known at this time, because the path forward has already been trodden, if .
Why setting up a Magma Testbed at Krafla?
By drilling through the rock–magma interface and into magma, we can establish where and under what conditions magma is stored beneath a volcano. Stimulate its boundary region by fluid injection to see whether the result is indeed measurable as the inferred unrest and ultimately place sensors near and even in magma to provide direct measurement of a rise in temperature, extent of crystallisation, change in gas content, or increase in pressure that could lead to eruption
Geothermal energy is environmentally friendly, renewable energy source and independent of weather conditions. It produces reliable baseload power and heat – all the more important to balance intermittent supplies from other renewable energy sources.
The establishment of KMT will tremendously benefit further research and development on extracting heat directly from magma, increasing the heat energy extractable from a geothermal field by an order of magnitude and the efficiency of conversion to electricity by a factor of two or three.
KMT will provide the opportunity to work at the limits of technology in drilling, materials, and sensor systems in a dynamic environment. It extends from crystallizing magmas at 900°C, 50 MPa, and 2100 m depth transitioning upward within 30 m abruptly to solid rock at 350°C and then through a producing geothermal system to ambient atmospheric temperature and pressure at the surface.
As well as providing an extreme environment for unprecedented research and for developing the commercial geothermal opportunity of supercritical steam, Krafla will drive innovation from Technology Readiness Level 1 (TRL1)
Iceland has already shown innovation in using its natural beauty and power to build a tourist industry. KMT provides such an opportunity in creation of a visitor centre with real time monitoring, 4d display areas, this would attract tourists to the region and provide schools and universities with a unique field environment for studies.
This would be an additional attraction in Northern Iceland and further enhance the economy in this area. It would also provide a training area for best-practice in industrial and environmental management in these environments which could be exported to developing regions, e.g., East Africa, Central America, which require a well-managed clean energy system to underpin their economic development.
- Characterize the physical, chemical, and mechanical properties of the interval between the Krafla hydrothermal system and magma. Use these direct observations to infer the mechanisms and fluxes of mass and heat.
- Use the improved “ground truth” knowledge of the subsurface from KMT-1 and neighboring wells to test and further develop surface geophysical and geochemical techniques for locating magma bodies at depth and predicting their characteristics.
- Carefully record geophysical observations during drilling and fluid injection to detect signals such as microseismicity, harmonic tremor, and inflation that are commonly classified as “unrest”, and to test models for their generation (e.g., pressure sources, induced seismicity, fluid flow in fractures causing vibration, etc.).
- Test and improve temperature and pressure sensors for extreme conditions.
- Complete the well for use for long-term monitoring and for re-entry for subsequent coring and observation of magma.