The Morro São João intrusion is located in the easternmost part of the Serra do Mar province, along the Cabo Frio lineament (Fig. 1) and has an area of approximately 10 km². It is a Late Cretaceous intrusion formed by clinopyroxenites, melagabbros, shonkinites, malignites, nepheline syenites, and phonolite dikes, without olivine, and is thought to have formed by closed system crystallization of a fairly evolved tephritic melt of potassic/ultrapotassic affinity (cf. Brotzu et al., 2007).
We have analyzed two malignites, and specifically, their liquidus phases (clinopyroxene, titanite, garnet, amphibole). Analyzing the trace elements in these minerals helps us to better understand the different fractionation of the elements in these coexisting phases, and the implications for the evolution processes that occurred in the Morro São João magma reservoir. These analyses also provided important information about the concentration of rare earth elements (REEs) and high field strength elements (HFSEs), and their change with the magmatic evolution of the suite.
This publication results from work conducted under the transnational access/national open access action at Mass spectrometry la-icp laboratory (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.
The Upper Cretaceous Salitre intrusion, subdivided into Salitre I and Salitre II and dated to ~86-82 Ma by Sonoki and Garda (1988), is part of the Alto Paranaíba Igneous Province (APIP, Fig. 1) in Brazil, which is one of the largest ultrapotassic / carbonatitic / kimberlitic provinces in the world. The intrusion is characterized by the presence of lamproites, carbonatites and one lamprophyre (analyzed here), as well as along with a variety of intrusive cumulitic rocks.
Among the Salitre studied samples, this alkaline lamprophyre is characterized by low SiO2 (35.6 wt%), ultrapotassic (K2O/Na2O = 5; K2O = 4.4 wt%) and peralkaline (PI = 1.3). It exhibits variable MgO content (14 wt%) and is enriched in REEs (∑REE=~1,300 ppm) and other trace elements (Nb, Ta, Zr, Hf, Sr, Ba). This lamprophyre is characterized by olivine and phlogopite phenocrysts set in a fine-grained groundmass of clinopyroxene, apatite, phlogopite, magnetite, chromite, and perovskite, with rare titanite and garnet; kalsilite is absent.
Analyzing the trace elements of the main minerals in this lamprophyre helped us learn more about the origin and evolution of these magmas, as well as their possible genetic link with the other Salitre rocks. This analysis also provided important information about their enrichment in rare earth elements (REEs) and high field strength elements (HFSEs).
This publication results from work conducted under the transnational access/national open access action at Mass spectrometry la-icp laboratory (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.
The Salitre intrusion, which is subdivided into Salitre I and Salitre II. It was dated to ~86-82 Ma by Sonoki and Garda (1988). It is part of the Alto Paranaíba Igneous Province (APIP, Fig. 1) in Brazil. The APIP is one of the largest ultrapotassic/carbonatitic/kimberlitic provinces in the world. The intrusion consists of lamproites, carbonatites, and one lamprophyre, as well as various intrusive cumulitic rocks. These rocks include perovskite-phlogopite dunites, phlogopite-perovskite clinopyroxenites (salitrites, s.l.), phlogopitites, phoscorites, and perovskitites. These rocks are characterized by variable enrichment of olivine, clinopyroxene, phlogopite, perovskite, oxides, apatite, and carbonate, as well as several accessory phases, such as baddeleyite and calzirtite. Their geochemical and petrological features are related to the variable amounts of these minerals.
For this part of the project, we have analyzed the concentrations of trace elements in the primary minerals (clinopyroxene, phlogopite, garnet, perovskite, apatite and olivine) identified in three phlogopite-perovskite clinopyroxenites and one perovskite-phlogopite dunite.
Analyzing the trace elements in these minerals helped us to better understand the differential settling of minerals within the Salitre magma chamber, and their possible genetic relationship with carbonatitic and lamprophyric rocks. These analyses also provided important information about the minerals' enrichment in rare earth elements (REEs) and high field strength elements (HFSEs).
This publication results from work conducted under the transnational access/national open access action at Mass spectrometry la-icp laboratory (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.
This dataset comprises the analyses of the intraoceanic arc rocks of the Olyutorsky terrain: major elements, minor elements, platinum-group elements, Rb-Sr, Sm-Nd, Lu-Hf and Pb-Pd isotopic systems. Samples are late Cretaceous in age and comprise picrites from the Tumrok and Valaginsky Ranges, and picrites, magnesian basalts and basalts from the Koryak Highlands. Major elements were measured by XRF, minor/trace elements by ICP-MS at the University of Tasmania (in 2019) and the Russian Geological Institute (in 2015); platinum-group elements were measured by ICP-MS using the Ni sulfide fire assay-isotope dilution method at the Seoul National University. Radiogenic (Sr-Nd-Hf-Pb) isotope compositions were determined at the University of Melbourne and the Institute of the Earth’s Crust, Irkutsk, using multi-collector ICP-MS in 2019.
A subset of these data were originally published as a supplement to Kutyrev et al. (2021), Primitive high-K intraoceanic arc magmas of Eastern Kamchatka: Implications for Paleo-Pacific tectonics and magmatism in the Cretaceous, Earth-Science Reviews 220, 103703, https://doi.org/10.1016/j.earscirev.2021.103703.
This work was funded by the Ministry of Science and Higher Education of the Russian Federation (Grant No. 075-15-2019-1883), The National Research Foundation (NRF) of Korea (Grant No. 2019R1A2C1009809A) and the Russian Science Foundation (Grant No. 21-17-00122).