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In pursuit of intrusions and not hiding failed experiments

Alison Graettinger 1, Ivana Torres-Ewert1, Ingo Sonder2, Susan Sakimoto3

Abstract

Techniques leveraging liters of remelted basaltic rock to investigate volcanic phenomena have advanced rapidly in the last decade. A series of experiments at SUNY Buffalo established that force can be applied to molten basalt to create intrusive deposits in unconsolidated sediment. The reproducibility of these experiments was limited by continued exploration of apparatus improvements, but proof-of concept was established. These preliminary experimental intrusions provide valuable context for the scale of intrusive bodies in the presence of coolants (air, water, host substrate) and demonstrate aspects of heat transfer along complex geometries. Intrusions were created through gravitational forces on a lava static head in a pool by pushing rebar into the base to create intrusive pathways, or through a proto-type plunger device. These experiments produced mm to cm thick intrusive bodies that could extend up to 10 cm away from the outlet with convoluted geometries. Melt would travel into the sediment to the lowest pressure, which in many cases was up through the sediment pile or backwards towards the apparatus. These small intrusions produced concentric color changes in the host sediment. Sediment particles were also incorporated into the margins of intrusive bodies with larger (0.5 cm) particles reaching up to 1 cm away from the contact. As water content exceeded ~11 % by volume the intrusions failed by freezing in the apparatus conduit. Although logistics prohibited a full suite of intrusion experiments the samples and observations provide valuable inputs for interpreting natural deposits, numerical simulations, and potential future experimental designs.