Post-orogenic shoshonitic magmas of the Yzerfontein pluton, South Africa: the 'smoking gun' of mantle melting and crustal growth during Cape granite genesis?

The post-orogenic Yzerfontein pluton, in the Saldania Belt of South Africa was constructed through numerous injections of shoshonitic magmas. Most magma compositions are adequately modelled as products of fractionation, but the monzogranites and syenogranites may have a separate origin. A separate high-Mg mafic series has a less radiogenic mantle source. Fine-grained magmatic enclaves in the intermediate shoshonitic rocks are autoliths. The pluton was emplaced between 533 ± 3 and 537 ± 3 Ma (LASF-ICP-MS U–Pb zircon), essentially synchronously with many granitic magmas of the Cape Granite Suite (CGS). Yzerfontein may represent a high-level expression of the mantle heat source that initiated partial melting of the local crust and produced the CGS granitic magmas, late in the Saldanian Orogeny. However, magma mixing is not evident at emplacement level and there are no magmatic kinships with the I-type granitic rocks of the CGS. The mantle wedge is inferred to have been enriched during subduction along the active continental margin. In the late- to post-orogenic phase, the enriched mantle partially melted to produce heterogeneous magma batches, exemplified by those that formed the Yzerfontein pluton, which was further hybridized through minor assimilation of crustal materials. Like Yzerfontein, the small volumes of mafic rocks associated with many batholiths, worldwide, are probably also lowvolume, high-level expressions of crustal growth through the emplacement of major amounts of mafic magma into the deep crust.IS

Granitic caves from the Achala Batholith in the Province of Córdoba, Argentina: A study on three particular stories with a common past

The igneous or magmatic rocks, especially those with granitic composition, constitute a special type of geomorphological substrate. As fromits exposure on the Earth´s surface and the modelling that eventually takes placeon them, different landscapes with specific characteristics emerge where inherited and present shapes coexist making possible to reconstruct the landscape evolution of the massif. Traditionally, in the studies of granitic landscapes,only the forms observed on the surface are described, where as those that develop underground are not often taken into consideration. In this paper three caves are analysed in order to specify their particular origins and classify it according to its morphological characteristics and the genetic processes involved. These caves are located on the same scarp of the rock massif and, therefore, share a geological and geomorphological common history, which is shown in their hypothesis of evolution. In addition, based on the type of cavityand certain observations of their environments it is possible to establish a relative chronological order in their ages of formation. In this context, it is proven that these underground environments (as the other geographical accidents andgranitic landforms) are not chaotic but - on the contrary- they are structured ingeological and geomorphological processes over time and they respond to acommon evolutionary framework to the entire rock massif. More detailed studies on these environments can develop in new methodological tools to understand the geological history of the granitic landscape they are located in.Fil: García Aráoz, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología Aplicada; ArgentinaFil: Madelon, Nicolás. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Pleitavino, Micaela Natalí. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Boretto, Gabriella Margherita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Cioccale, Marcela Alejandra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Genetic dissection of tomato rootstock effects on scion traits under moderate salinity

The present study approaches the QTL dissection of rootstock effects on a commercial hybrid variety grafted on a population of RILs derived from Solanum pimpinellifolium, genotyped for 4370 segregating SNPs from the SolCAP tomato panel and grown under moderate salinity. Results are compared to those previously obtained under high salinity. The most likely functional candidate genes controlling the scion [Na+] were rootstock HKT1;1 and HKT1;2 as it was previously reported for non-grafted genotypes. The higher fruit [Na+] found when rootstock genotype was homozygote for SpHKT1 supports the thesis that scion HKT1 is loading Na+ into the phloem sap in leaves and unloading it in sink organs. A significant increment of small, mostly seedless, fruits was found associated with SlHKT1 homozygous rootstocks. Just grafting increased the incidence of blossom end rot and delayed fruit maturation but there were rootstock RILs that increased commercial fruit yield under moderate salinity. The heritability and number of QTLs involved were lower and different than those found under high salinity. Four large contributing (>17 %) rootstock QTLs, controlling the leaf concentrations of B, K, Mg and Mo were detected whose 2 Mbp physical intervals contained B, K, Mg and Mo transporter-coding genes, respectively. Since a minimum of 3 QTLs (two of them coincident with leaf K and Ca QTLs) were also found governing rootstock-mediated soluble-solids content of the fruit under moderate salinity, grafting desirable crop varieties on stress-tolerant rootstocks tenders an opportunity to increase both salt tolerance and quality