LIMBIC - LInking Magma Batch Intrusion to the Construction
of geothermal systems and mineral deposits

A research project that stidues how magma chambers grow and how that influences geothermal systems and ore formation.

Details

  • Period: 2021-01-01 – 2024-12-31
  • Budget: 3,520,000 SEK
  • Funder: Swedish Research Council
  • Type of funding: Project Grant

Description

Since geology as a science began to take shape in the late 1700s and large solidified magma chambers were identified at the Earth's surface, people wondered how such large amounts of molten magma could accumulate in the Earth's crust.

Large magma chambers are a prerequisite for large volcanic eruptions and also play a significant role in the transport of heat and substances in the Earth's crust. However, in the early 2000s, more and more results from modern measurement methods began to suggest that such large magma chambers either did not exist or were extremely short-lived phenomena. We now understand that the large solidified and all active magma chambers were formed through the accumulation of smaller amounts of magma, called magma pulses, over a long period of time. This insight means, on the one hand, that large volcanic eruptions require specific conditions. These conditions can be simulated using computer models based on a variety of assumptions, such as the size of the magma pulses. Less is known about how magma pulses affect the transport of heat and magmatic substances such as water and precious metals. Understanding the interaction between these processes is crucial for improving our knowledge of how hydrothermal systems and ore deposits form, which is important for the production of geothermal energy and the sustainable extraction of rare mineral resources.

This project aims to study a solidified magma chamber that we know was formed from an accumulation of magma pulses and to determine the size, shape, and way the pulses intruded into the Earth's crust. In addition, we will investigate how individual magma pulses affected the surrounding rock and earlier pulses, as well as how water and magmatic substances were transported. We will do this through field measurements and sampling, but also by taking high-resolution images with drones. The drone images will be used to create three-dimensional maps of the magma chamber, which will form the basis for our reconstruction of the magma pulses. The rock samples will be used to determine the composition of the magma pulses, signs of the direction of magma flow, and the composition of the released magmatic substances. Microscopic fluid inclusions in the samples may also reveal the temperature during hydrothermal circulation. Since water and dissolved magmatic substances are preferentially transported through fractures, we will identify the presence of minerals in the fractures in the field and on our samples and map three-dimensional fracture networks using the three-dimensional maps. The fracture mineralization will be linked to the composition of individual magma pulses, and the digitized fracture networks will then be used to simulate hydrothermal circulation within and around the magma chamber. In this way, we can connect how each magma pulse contributed to hydrothermal circulation and mineralization.

Our project will, for the first time, provide quantitative data on magma pulse size and shape, which is needed to improve computer models of magma chambers that can lead to large volcanic eruptions. Additionally, the project will contribute to a better understanding of how magma pulses affect hydrothermal circulation and material transport in and around magma chambers. Since these processes are crucial for the formation of geothermal systems and precious metal deposits, this project will ultimately contribute to a better supply of geothermal energy and mineral resources.

Stockholm University (Sweden)

University of Birmingham (England)

Icelandic Institute of Natural History (Iceland)

Project members

Project leader: Steffi Burchardt
Co-investigators: Birgir Óskarsson (Icelandic Institute of Natural History), Carl Stevenson (University of Birmingham), Iain Pitcairn (Stockholm University)

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