Publication Date:
2023-09-12
Description:
Ascending magma is always interacting with its surrounding country rock, as evidenced by crustal xenoliths in volcanic products. In the case of a limestone basement this interaction, also called carbonate assimilation, may significantly affect eruption dynamics due to the limestones ability to release CO〈sub〉2〈/sub〉 if heated above its crystallographic stability. Examples for such a setting include volcanic systems like Colli Albani, Etna, Merapi, Pacaya, Popocatepetl and Somma-Vesuvius. Previous carbonate assimilation studies at magma chamber conditions have already shown that this interaction might release CO〈sub〉2〈/sub〉 and dissolve the ingested clast in syn-eruptive timescales. With our novel experimental procedure, we investigated the interaction of a magma with an ingested limestone at the second endmember of the volcanic feeding system (i.e., Earth’s surface and hence at atmospheric pressure). Our set-up allowed, for the first time, to discriminate between the individual processes within the carbonate assimilation (namely decarbonation and clast dissolution), their respective timescales and their controlling parameters. By comparing the results of both experimental approaches, we were able to qualitatively extrapolate the conditions and outcomes of magma carbonate interactions throughout the whole volcanic feeding system, from magma chamber to Earth’s surface. This enables a qualitative distinction of which process (decarbonation or clast dissolution) is dominant in which conditions and how the syn-eruptive interaction of magma with carbonate-bearing wall-rocks within the feeding dyke of an eruption will influence the eruptive behaviour.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
Permalink
