Subgroup growth is an important new area of group theory. It attempts to quantify the number of finite index subgroups of a group, as a function of their index. In this paper, we will provide new, strong lower bounds on the subgroup growth of a variety of different groups. This will include the fundamental groups of all finite-volume hyperbolic 3-manifolds. By using the correspondence between s...

Geothermal exploration targets large magmatic intrusions as heat sources because of their size, longevity, and amount stored energy, but shallow volcanic plumbing systems comprise numerous smaller intrusions, geothermal potential warrants consideration. Here, we evaluate the impact dykes sills on caldera-infill rocks. We present geological data geothermometry in eroded Breiðuvík caldera Northea...

The composition of the intrusive gabbroic lower oceanic crust remains poorly characterized in comparison to extrusive portion crust, especially for intermediate-fast spreading mid-ocean ridges. This is a consequence limited exposures extant or ophiolites similar ridge crust. One best analogues southern Samail ophiolite that formed during period rapid seafloor above nascent subduction zone. Here...