Geophysical modeling of Serra Negra and Salitre I, II and III alkaline-carbonatite complexes based on their gravimetric and magnetic signatures

Santos, Roberto dos; Mantonavi, Marta; Marangoni, Yára Regina

doi:10.22564/16cisbgf2019.226

Cited by 1 publication

(1 citation statement)

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“…Recent developments in joint 3-D inversion of gravity and magnetic data were used to map a nepheline monzogabbro pipe in the Kaiserstuhl alkaline silicate and carbonatite complex in Germany (www.terratec-geoservices. com; dos Santos et al, 2019).…”

Section: Prospect and Deposit-scale Characteristicsmentioning

confidence: 99%

Alkaline-Silicate REE-HFSE Systems

et al. 2023

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Development of renewable energy infrastructure requires critical raw materials, such as the rare earth elements (REEs, including scandium) and niobium, and is driving expansion and diversification in their supply chains. Although alternative sources are being explored, the majority of the world’s resources of these elements are found in alkaline-silicate rocks and carbonatites. These magmatic systems also represent major sources of fluorine and phosphorus. Exploration models for critical raw materials are comparatively less well developed than those for major and precious metals, such as iron, copper, and gold, where most of the mineral exploration industry continues to focus. The diversity of lithologic relationships and a complex nomenclature for many alkaline rock types represent further barriers to the exploration and exploitation of REE-high field strength element (HFSE) resources that will facilitate the green revolution. We used a global review of maps, cross sections, and geophysical, geochemical, and petrological observations from alkaline systems to inform our description of the alkaline-silicate REE + HFSE mineral system from continental scale (1,000s km) down to deposit scale (~1 km lateral). Continental-scale targeting criteria include a geodynamic trigger for low-degree mantle melting at high pressure and a mantle source enriched in REEs, volatile elements, and alkalies. At the province and district scales, targeting criteria relate to magmatic-system longevity and the conditions required for extensive fractional crystallization and the residual enrichment of the REEs and HFSEs. A compilation of maps and geophysical data were used to construct an interactive 3-D geologic model (25-km cube) that places mineralization within a depth and horizontal reference frame. It shows typical lithologic relationships surrounding orthomagmatic REE-Nb-Ta-Zr-Hf mineralization in layered agpaitic syenites, roof zone REE-Nb-Ta mineralization, and mineralization of REE-Nb-Zr associated with peralkaline granites and pegmatites. The resulting geologic model is presented together with recommended geophysical and geochemical approaches for exploration targeting, as well as mineral processing and environmental factors pertinent for the development of mineral resources hosted by alkaline-silicate magmatic systems.

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Section: Prospect and Deposit-scale Characteristicsmentioning

confidence: 99%