Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

The Mesoproterozoic MARA terrane of western South America is a composite igneous-metamorphic complex that is important for Paleozoic paleogeographic reconstructions and the relative positions of Laurentia and Gondwana. The magmatic and detrital records of the MARA terrane are consistent with a Laurentian origin; however, the metamorphic and deformation records lack sufficient detail to constrain the correlation of units within the MARA terrane and the timing and mechanisms of accretion to the Gondwana margin. Combined regional mapping, metamorphic petrology, and garnet and monazite geochronology from the Sierra de Maz of northwest Argentina sug- gest that the region preserves four distinct litho-tectonic units of varying age and metamorphic conditions that are separated by middle- to lower-crustal ductile shear zones. The Zaino and Maz Complexes preserve Barrovian metamorphism and ages that are distinct from other units within the region. The Zaino and Maz Complexes both record metamorphism ca. 430–410 Ma and show no evidence of the regional Famatinian orogeny (ca. 490–455 Ma). In addition, the Maz Complex records an earlier granulite facies event at ca. 1.2 Ga. The Taco and Ramaditas Complexes, in contrast, experienced medium- and low-pressure upper amphibolite to granulite facies metamorphism, respectively, between ca. 470–460 Ma and were later deformed at ca. 440–420 Ma. The Maz shear zone that bounds the Zaino and Maz Complexes records sinistral oblique to sinistral deformation between ca. 430–410 Ma. The data suggest that at least some units in the MARA terrane were accreted by translation, and the Gondwana margin of northwest Argentina transitioned from a dominantly convergent margin to a highly oblique margin in the Silurian.

El pretérito pluscuamperfecto como marca de género narrativo en el español andino del Noroeste de la Argentina

In her research about the past tense forms from the Quechua Southern Conchucos lands (Ancash, Peru), Hintz (2007) finds equivalences between some functions of the narrative structure of both the past tense in Quechua and the past tense in Spanish among the bilingual speakers of Quechua-Spanish. In this work, we analyze a group of not-experienced native speakers’ oral testimonies of Andean Spanish from Northwest Argentina. We seek to find a mutual relation between evidential and affect functions of the Quechua suffix -na: and the use of the pluperfect of Andean Spanish. Our findings show that there is a partial grammar barrowing between the two forms. We envisage also that the pluperfect appears remarkably more often in certain parts of the narrative structure, usually along with one of the decir verb forms as a metadiscursive markers (Chang, 2018 and 2019).

Two new species of Andinopanurgus (Hymenoptera: Andrenidae: Panurginae), with a description of the female of A. amyae

Two new species of Andinopanurgus Gonzalez & Engel are described: Andinopanurgus chirosimpson Packer, new species, from northwest Argentina extends the range of the genus south by more than 2000 km and A. lynnae Packer, new species, from Peru. The new species seem to belong to Gonzalez & Engel’s “guarnensis species group” but differ from it in the highly modified setae on S4, which are divided into two to four branches (in A. chirosimpson, the four-branched ones of which look like a thumbless hand and are the source of the specific epithet) to two to five branches (in A. lynnae). The female of A. amyae (Gonzalez & Engel) is described for the first time.

Composition of Prehispanic Diets from Stable Isotope Analysis in Human Remains of the Southern Calchaquíes Valleys, Northwest Argentina (3600–1300 BP)

This article discusses the composition of prehispanic diets based on the isotopic composition (δ13C, δ15N) of 10 human samples dated between 3600 and 1300 BP from the Cajón Valley in Northwest Argentina. The sample is the only one available for the time and region considered and covers a 2,300-year range. It shows long-term tendencies in the consumption of food resources during a time when people were experimenting with and eventually domesticating plants and animals in the high-altitude Southern Calchaquíes valleys. Results indicate that animals contributed more to the diet than was expected and plants correspondingly less than expected. This proportion was maintained even during the human occupations associated with the agropastoral villages of Cardonal and Bordo Marcial (ca. 2000 BP) when a greater contribution of plant resources—in particular maize—would be expected. This new evidence demonstrates the diversity of productive strategies used by the societies of Northwest Argentina at the beginning of the Formative period. A variety of resources contributed to daily food intake, minimizing the importance of maize in the diet.