Characterizing the Source of the Eastern Galicia Magnetic Anomaly (NW Spain): The Role of Extension in the Origin of Magnetization at the Central Iberian Arc

Abstract

Aeromagnetic data are a valuable source of geological information. Regional datasets have been commonly used to (1) establish the depth to the Curie Point and hence the thermal structure of large areas (An

Barren ground depressions, natural H2 and orogenic gold deposits: Spatial link and geochemical model

“…Siderite is paramagnetic whereas magnetite is ferromagnetic, producing a strong magnetization. This is consistent with the observation of strong magnetic anomalies in sediment-hosted gold deposits such as those found in northwestern Spain (Ayarza et al, 2021) and in the Otago Schist (New Zealand; Blundell et al (2019)). Naudé et al (2011) also measured a concentration of magnetic minerals (probably magnetite) in the center of fairy circles.…”

Four decades of geophysical research on Iberia and adjacent margins

“…Beneath the northern part of the Variscan Massif, the most significant anomaly is the Eastern Galicia Magnetic Anomaly (EGMA), oriented along a NNW-SSE direction. This anomaly has recently been investigated by Ayarza et al (2021b), that linked its magnetization to the presence of extensional structures developed in late Carboniferous/earliest Permian times. Further south, the magnetic anomalies beneath the Ossa Morena and South Portuguese Zones are of shorter extension and show a rather continuous WNW-ESE orientation.…”