Many prospective sedimentary basins contain a variety of extrusive volcanic products that are ultimately sourced from volcanoes. However, seismic reflection-based studies of magmatic rift basins have tended to focus on the underlying magma plumbing system, meaning that the seismic characteristics of volcanoes are not well understood. Additionally, volcanoes have similar morphologies to hydrothermal vents, which are also linked to underlying magmatic intrusions. In this study, we use high resolution 3D seismic and well data from the Bass Basin, offshore southern Australia, to document 34 cone-and crater-type vents of Miocene age. The vents overlie magmatic intrusions and have seismic properties indicative of a volcanic origin: their moderate-high amplitude upper reflections and zones of "wash-out" and velocity pull-up beneath. The internal reflections of the vents are similar to those found in lava deltas, suggesting they are composed of volcaniclastic material. This interpretation is corroborated by data from exploration wells which penetrated the flanks of several vents. We infer that the vents we describe are composed of hyaloclastite and pyroclasts produced during submarine volcanic eruptions. The morphology of the vents is typical of monogenetic volcanoes, consistent with the onshore record of volcanism on the southern Australian margin. Based on temporal, spatial and volumetric relationships, we propose that submarine volcanoes can evolve from maars to tuff cones as a result of varying magma-water interaction efficiency. The morphologies of the volcanoes and their links to the underlying feeder systems are superficially similar to hydrothermal vents. This highlights the need for careful seismic interpretation and characterization of vent structures linked to magmatic intrusions within sedimentary basins.

Continental rifting is often associated with voluminous magmatism and perturbations in the Earth's climate. In this study, we use 2D seismic data from the northeast Greenland margin to document two Paleogene-aged sill complexes ≥18 000 and ≥10 000 km 2 in size. Intrusion of the sills resulted in the contact metamorphism of carbon-rich shales, producing thermogenic methane which was released via 52 newly discovered hydrothermal vent complexes, some of which reach up to 11 km in diameter. Mass balance calculations indicate that the volume of methane produced by these intrusive complexes is comparable to that required to have caused the negative δ 13 C isotope excursion associated with the PETM. Combined with data from the conjugate Norwegian margin, our study provides evidence for margin-scale, volcanically-induced greenhouse gas release during the late Paleocene/early Eocene. Given the abundance of similar-aged sill complexes in Upper Paleozoic-Mesozoic and Cretaceous-Tertiary basins elsewhere along the northeast Atlantic continental margin, our findings support a major role for volcanism in driving global climate change.

8There is growing evidence that intrusive magmatic bodies such as sills and dikes can 9 influence the migration of fluids in the deep subsurface. This influence is largely due to 10 is directly overlain by a vertical feature interpreted to be a fluid escape pipe, which extends 20 vertically for ~700 m across the late Miocene-Pliocene succession. We suggest the buried volcanic 21 complex was able to focus vertical fluid migration to the base of the pipe because its bulk 22 permeability was higher than that of the overlying claystone sequence. The fluid escape pipe may 23 have initiated through either: 1) hydraulic fracturing following fluid expulsion from a deep, 24 overpressured sub-volcanic source region; 2) differential compaction and doming of the overlying 25 claystones; or 3) through a combination of these processes. Our results suggest a hitherto 26

Analysis of the " electronic factor " in heterogeneous catalysis suggests that activity of Ni-Fe alloys in multiple bond hydrogenation should increase rapidly in the region where the energy density of electron levels a t the Fermi surface rises ; moreover, that reactions controlled by the rate of transfer of an electron from metal t o substrate should, in the Ni-Cu alloys, decrease in rate as the 3d-band begins t o empty. Experiments on styrene hydrogenation over Ni-Fe catalysts and hydrogen peroxide decomposition on Ni-Cu alloy foils provide general confirmation of these predictions. Methanol and formic acid decompositions on the Ni-Cu alloys decrease in speed as the 3d-band