In the North Atlantic, cold, relatively salty water sinks in the icy Labrador and Greenland seas, forming North Atlantic Deep Water (NADW).This circulates through the global ocean, driving ocean overturning and global heat transport and, thus, impacting global climate. As one of the most climatically sensitive regions on Earth, the North Atlantic has experienced abrupt changes to its oceanatmosphere‐cryosphere system, triggered by fluctuations in meltwater delivery to source areas of NADW formation. For about the past 100 thousand years, these abrupt jumps in climate state have manifested as ‘Dansgaard/Oeschger’ (D/O) oscillations (millennial‐scale warm‐cold oscillations) and 'Heinrich' events in ice and marine sediment cores, respectively [e.g., Dansgaard et al., 1993; Bond and Lotti, 1995]. These Heinrich events are characterized as huge input of ice‐rafted debris (IRD) and meltwater pulses, documenting episodes of sudden instability and collapse of the current Greenland ice sheets and the Laurentide ice sheet, the latter of which covered northern North America several times during the Pleistocene Epoch.

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There is little argument about the merits of undergraduate research, but it can seem like a complex, resource‐intensive endeavor [e.g., Laursen et al., 2010; Lopatto, 2009; Hunter et al., 2006]. Although mentored undergraduate research can be challenging, the authors of this feature have found that research programs are strengthened when students and faculty collaborate to build new knowledge. Faculty members in the geology department at The College of Wooster have conducted mentored undergraduate research with their students for more than 60 years and have developed a highly effective program that enhances the teaching, scholarship, and research of our faculty and provides life‐changing experiences for our students. Other colleges and universities have also implemented successful mentored undergraduate research programs in the geosciences. For instance, the 18 Keck Geology Consortium schools (http://keckgeology.org/), Princeton University, and other institutions have been recognized for their senior capstone experiences by U.S. News & World Report.

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Geoscientists, naturalists, and rock-hound enthusiasts have explored Ice Springs volcanic field (ISVF) for nearly 130 years because it is one of the youngest, extension-related volcanic centers in Utah and the Southwest U.S. Ice Springs received its name due to the presence of ice within its expansive a’a lava flows (Davis, 2014), which have an interesting age discrepancy. Previous work on Ice Springs dated the ISVF as 660 years old (Valastro and others, 1972), but we now introduce an age date of 9,800 to 11,100 years old. Although the eruptive and effusive deposits (more explosive vs passive, respectively) capture our imagination today, it is possible that they were natural hazards for the early Paleo-Indians of the region.

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Glaciovolcanic landforms provide global-scale records of paleoenvironmental conditions and yield insights into subglacial eruption processes. Models for the formation of glaciovolcanic ridges, or tindars, are relatively simple, proposing a monogenetic eruption and a fairly uniform stratigraphy with or without a single transition from effusive pillow lavas to explosive fragmental deposits. Others have suggested that tindars are more complicated. To build a more robust model for tindar formation, we conducted a field and geochemical study of Undirhlíðar ridge on the Reykjanes Peninsula in southwestern Iceland. We show that the ridge was built through a complex sequence of eruptive and intrusive events under dynamically changing ice conditions. Quarry walls expose a continuous cross-section of the ridge, revealing multiple pillow and fragmental units. Pillow lava orientations record the emplacement of discrete pillow-dominated lobes and the migration of volcanic activity between eruptive vents. Volatile contents in glassy pillow rinds show repeated pulses of pillow lava emplacement under glaciostatic conditions, with periods of fragmentation caused by depressurization. Variations in major elements, incompatible trace element ratios, and Pb-isotopes demonstrate that the eruption was fed from separate crustal melt reservoirs containing melts from a compositionally heterogeneous mantle source. A shift in mantle source signature of pillow lavas suggests that the primary ridge-building phase was triggered by the injection of magma into the crust. Within the growing edifice, magma was transported through dykes and irregularly shaped intrusions, which are up to 20% by area of exposed stratigraphy sequences. The model for tindar construction should consider the significant role of intrusions in the growth of the ridge, a detail that would be difficult to identify in natural erosional exposures. The 2021–22 eruptions from the adjacent Fagradalsfjall vents allow us to draw parallels between fissure-fed eruptions in subaerial and ice-confined environments and test hypotheses about the composition of the mantle underlying the Reykjanes Peninsula. Both Fagradalsfjall and Undirhlíðar ridge eruptions may have occurred over similar spatial and temporal scales, been triggered by mixing events, erupted lavas with varying mantle source signatures, and focused volcanic activity along migrating vents. Differences in composition between the two locations are not related to systematic lateral variations in the underlying mantle. Rather, the Undirhlíðar ridge and Fagradalsfjall eruptions capture complex interactions among the crustal magma plumbing system, mantle source heterogeneity, and melting conditions for a moment in time.