Plumbing systems of large igneous provinces (LIPs) on Earth and Venus: Investigating the role of giant circumferential and radiating dyke swarms, coronae and novae, and mid-crustal intrusive complexes

Abstract The flood basalts of large igneous provinces (LIPs) are fed by a vast and often complicated plumbing system that can include giant dyke swarms, sill complexes, mid- to upper-crustal intrusive complexes, lower-crustal intrusions and a magmatic underplate at the base of the crust. In this study, we focus on the role of two poorly understood and little studied components of LIP plumbing systems: giant circumferential dyke swarms and mid-crustal igneous complexes. Giant circumferential dyke swarms, which have only recently been recognized, are often associated with giant radiating dyke swarms, whose foci are located at or near the centre of the circumferential swarms. The giant radiating swarms are usually interpreted to be generated during domal uplift above a mantle plume. We compare giant circumferential dyke swarms, giant radiating dyke swarms and coupled circumferential-radiating dyke systems with possible analogues on Venus, called coronae, novae and corona-nova systems, respectively. Coronae are large tectonomagmatic features that typically include a quasi-circular/elliptical annulus of graben that are thought to be underlain by dykes. Novae are large radiating graben systems that are also thought to be underlain by dykes. Coronae, novae and coupled corona-nova systems are usually interpreted to be generated above mantle plumes or diapirs. In addition, we discuss the potential importance of mid-crustal intrusive complexes in LIP plumbing systems, especially those that may be circumferential to plume centres. Given their location they could act as feeders to either giant radiating or giant circumferential dyke swarms, or both.