Kilometer 4 and the Archaic Period Occupation of the Ilo Area of Southern PerúMore than a decade of research on a series of Archaic Period (roughly 10,000-3000 BP) sites in the Ilo area of southern Peru have yielded enough data on this previously unknown area to outline the long term patterns of development of the Preceramic cultures of this section of the south-central Andean coast. Research at several sites, most notably the Kilometer 4 site, provides evidence of a long and intensive occupation of the region characterized by increasing sedentism and increasingly intensive maritime subsistence through time. During the Early Archaic and Middle Archaic periods, coastal settlements were small, seasonally occupied sites characterized by a mixed subsistence base. By the Late Archaic period, settlement size increased, architecture became more substantial and segregation of different areas within the site increased as the exploitation of coastal resources increased. Archaic period mortuary patterns in the region are clearly associated with those of coastal northern Chile, and preliminary data indicate that Chinchorro mortuary practices prevailed during the Middle Archaic period while Quiani style patterns emerged during the Late Archaic period. / Más de una década de investigaciones en una serie de sitios del Periodo Arcaico (entre 10.000 y 3000 a.p.) en el area de Ilo, al sur del Perú, han proveído datos significativos para esta área antes desconocida a fin de delinear los patrones a largo plazo del desarrollo de las culturas precerámicas de esta sección de la costa de los Andes centro-sur. Los estudios realizados en varios sitios, principalmente en Kilómetro 4, han producido evidencias de una larga e intensiva ocupación en la región, caracterizada por un incremento del sedentarismo y de la subsistencia marítima a través del tiempo. Durante los periodos Arcaico Temprano y Arcaico Medio, los asentamientos de la costa fueron sitios pequeños, ocupados estacionalmente y se caracterizaban por una base de subsistencia mixta. Hacia el Periodo Arcaico Tardío se incrementó el tamaño de los asentamientos y la segregación de diferentes áreas dentro de los mismos; la arquitectura comenzó a ser más sustancial y se intensificó la explotación de los recursos costeros. Los patrones funerarios en la región están claramente asociados con los de la costa norte de Chile, y los datos preliminares indican que las prácticas funerarias Chinchorro prevalecieron durante el Periodo Arcaico Medio, mientras que los patrones estilísticos Quiani emergieron durante el Periodo Arcaico Tardío.

Northern Perú’s Colonization and Settlement: Innovation, Technology and Adaptation at Zaña ValleyThis paper discusses the archaeological and paleoecological data for the first people to enter the Zaña Valley and their later development as sedentary horticulturalists. The technical, social and economic implications of these developments in regard to forming the foundations of early Andean civilization are also presented for the Early (ca. 10,000-7500 b.p.) and Middle (ca. 7500-5000 b.p.) Preceramic Periods. We discuss the Paijan, Nanchoc, Pircas and Tierra Blanca cultures in terms of their settlement patterns, bifacial and unifacial lithic technologies, economies, and social organization. The most important site complex is the Nanchoc Mound site, dated between 7200-5000 years ago, where lime seems to have been produced in a separate ritual space for consumption with coca leaves. The broader implications of these cultural transformations are discussed with respect to the importance of the Middle Preceramic Period for understanding the beginnings of central Andean civilization. / Se presenta un análisis arqueológico y paleoambiental de los primeros pobladores prehistóricos en el valle de Zaña y las siguientes etapas de desarrollo técnico y económico hacia la vida sedentaria y eventualmente la formación de la base de la civilización andina en la zona desde el Periodo Precerámico Temprano (ca.10.000-7500 a.p) al Periodo Precerámico Medio (ca. 7500-5000 a.p.). Más específicamente, se discuten las culturas de Paiján, Nanchoc, Pircas y Tierra Blanca en términos de los patrones de asentamientos, las tecnologías bifaciales y unifaciales y sus funciones espaciales y temporales, así como la organizacion social. Se destaca un conjunto de sitios precerámicos en la zona de Nanchoc, mejor definido por el yacimiento Montículos de Nanchoc, fechado entre 7200 y 5000 a.p. y su relación a la aparición de una tecnología de produción de cal, posiblemente usada para el consumo de coca, y de un asociado espacio «ritual». Las implicancias más amplias de estos cambios y procesos locales son discutidos en cuanto al valor histórico y científico del Periodo Precerámico Medio para el entendimiento de la base sociocultural de las sociedades complejas en los Andes Centrales.

Excavations at the site of Cerro Lampay allow evaluation of the role of ritual activities, such as feasting, in the organization of construction during the late Archaic Period. Excavations have provided a detailed documentation of building procedures that ended in the entombment of architectural compounds. Particularly important is that there was not a single, large-scale construction event, but several small-scale events that were accompanied by processing and consumption activities. This pattern strongly suggests a permanent reinforcement of ties and commitments between groups through feasting, which was as a required activity in order to complete the construction of public works. This scenario supports the idea of emerging leadership capable of mobilizing labor for the construction requirements. Nevertheless, the reliance on feasting as ritual practices, and the small scale of these events, suggests a limited power capacity and a weakly formalized authority, which needed to be constantly reinforced through the inferred ritual practices. / Las excavaciones realizadas en el sitio de Cerro Lampay, ubicado en el valle de Fortaleza, costa norcentral del Perú, permiten evaluar el rol de actividades, como los festines, en la organización de labores constructivas dentro del contexto del Periodo Arcaico Tardío. Estas excavaciones permitieron obtener un registro detallado de un proceso constructivo que concluyó con el "enterramiento" de los conjuntos arquitectónicos. Algo notorio es que la construcción no se dio en un solo evento, sino a lo largo de varios de pequeña escala antecedidos por actividades de procesamiento y consumo de alimentos. Este patrón de comportamiento sugiere que las actividades de consumo eran requeridas para la conducción de la construcción, probablemente como un mecanismo de refuerzo de compromisos establecidos entre el anfitrión del acto de consumo y quienes realizarían la construcción. Este escenario plantea la existencia de liderazgos emergentes, capaces de movilizar mano de obra para construcción. Sin embargo, el recurso de convocatoria a "festines" como prácticas ritualizadas y la pequeña escala de dichos eventos sugieren una capacidad de poder y convocatoria limitada y una autoridad no formalizada que requerirían de un reforzamiento constante por medio de las prácticas inferidas.

Some Contributions to the Chronology of the Archaic Period in the Punas of JunínThe stratigraphy and the typology from the Uchkumachay excavations are presented as well as preliminary results of a comparative study undertaken in collaboration with D. Lavallée and M. Julien. These data bear major importance on the building of a general chronology and synthesis of the Archaic Period which still is missing for the Junín area in spite of being one of the best studied areas in the Central Andes for the time period in question. / La estratigrafía y tipología de Uchkumachay, Junín, están presentadas así como los resultados preliminares de un estudio comparativo entre Uchkumachay y Telarmachay en colaboración con D. Lavallée y M. Julien. Estos resultados tienen mayor importancia para la formación de una cronología general del Periodo Arcaico en el área de Junín la cual es una de las áreas mejor estudiadas de los Andes Centrales durante este periodo pero que aguarda aún una síntesis general y la presentación más completa de los datos disponibles.

The Carved Gourd Vessels of Huaca Prieta: Evidence of Valdivia Art in Central Andean Archaic?The two carved gourd vessels discovered by Junius B. Bird in tomb no. 903 at Huaca Prieta, Chicama valley, have 1ong been considered as foreign elements in a cultural context that at first did not appear to be very complex (Bird 1948). Because of some design resemblances with contemporary Valdivia ceramics in southwest Ecuador, Edward P. Lanning (1967) proposed a northern derivation for both gourds and his suggestion has since been accepted widely. On the basis of iconographic evidence that has become available more recently, the present study intends to show that both gourds are legitimate examples of late Archaic central Andean art. / Los dos mates encontrados por Junius B. Bird en el entierro 903 de Huaca Prieta, valle de Chicama, se consideraron por mucho tiempo como extraños en un contexto cultural cuya complejidad no era aparente al principio (Bird 1948). Efectivamente, su decoración excisa hace recordar algunos motivos de la ceramica Valdivia en el Ecuador. Esta fue la razón por la cual Edward P. Lanning (1967) propusiera una filiación norteña de los mates, la que ha sido recalcada por varios autores. El estudio presente trata de reubicar estas obras dentro del arte arcaico centroandino.

Morro 1-5 (Arica). Mummies and Complex Societies in South Central AndesThe comparative study of a series of 17 mummies from the Morro 1-5 site in Arica, Chile, is used to discuss the adaptation of the Chinchorro culture of the Archaic period in the South Central Andes. Issues related to the origin and distribution of cultural traits such as artificial mummification and its tipology of forms, as well as biological aspects such as craniometric and epigenetic traits, are íntegrated in the presentation of one of the oldest, most efficient and complex adaptations to the fragile environment of the desertic coast of the South Central Andes. / A partir del estudio comparativo de una serie de 17 momias del sitio Morro 1-5 de Arica, Chile, se discute la adaptación de la cultura Chinchorro del Periodo Arcaico en los Andes Sur Centrales. Aspectos referentes al origen y la distribución de rasgos culturales como el uso de la momificación artificial y su tipología de formas, y biológicos como rasgos epigenéticos y craniométricos, se integran a la presentación de uno de los procesos más antiguos, eficientes y complejos en uno de los ambientes más frágiles del desierto costeño de los Andes Sur Centrales.

<p>This thesis focuses on the tectonomorphologic evolution of the Central Andean Puna Plateau and its eastern foreland. The collective findings of fault-slip and tectonomorphic analyes help in understanding the mechanical behavior of non-collisional orogens at convergent plate boundaries and result in an improved Neogene tectonic record of the Central Andes.</p> <p>Fault-slip analysis indicates Neogene WNW-ESE horizontal shortening of the thickened crust of the Puna Plateau and Eastern Cordillera and simultaneous lateral gravitational spreading. The less thickened of Pampean Ranges continue to undergo horizontal shortening only. The importance of N-S extension in the kinematics of elevated parts of the Central Andes is underscored by the strike-slip components on prominent dip-slip faults. Strain axis configurations in the southern Central Andes are generally controlled by (1) overall WNW-ESE horizontal shortening imposed by plate convergence and (2) differences in crustal thickness, i.e., gravitational potential energy. Therefore, a geodynamic interpretations in which still increasing elevation and crustal thickness significantly influence upper-crustal kinematics of the southern Central Andes is suggested.</p> <p>To allow regional-scale tectonomorphic studies, including Valley-Width-to-Valley-Height (Vf) ratio and the Transverse-Topographic-Symmetry (T-) factor, an Esri ArcGIS compatible software tool was developed. This Geographical Information System (GIS)-based tool, was coded in Python to enable conversion to other ArcGIS versions. This herein presented first version of the tool is fully functioning and drastically reduces the otherwise long processing times.</p> <p>A qualitative main basin symmetry description, Mountain-Front-Sinuosity (Smf) indices, and Vf-ratios of second-order drainage basins, indicate ubiquitous Quaternary deformation on reverse and thrust faults in the southern Central Andes. The recorded Quaternary deformation strongly influences Quaternary landform development, as shown by main drainage basin asymmetries and second-order drainage basins shapes. However, non-systematic T-factor distribution for second-order basins indicates that basin asymmetry is subject to litholigcal variations.</p> / Doctor of Philosophy (PhD)

A Sierra de Umango está localizada na porção ocidental da Província de La Rioja, no noroeste argentino. Situa-se na região do \"Pampean Flat-slab\" dos Andes Centrais e conforma um conjunto de blocos do embasamento, soerguidos e rotacionados no Cenozóico, denominado de Sierras Pampeanas Ocidentais. As Sierras Pampeanas Ocidentais são caracterizadas por rochas meta-ígneas de idade mesoproterozóica grenvilliana e unidades metassedimentares metamorfisadas no Ordoviciano, e são interpretadas como parte do Terreno Composto Cuyania. As rochas metamórficas da região de Umango são limitadas a oeste por rochas sedimentares devonianas da Pré-Cordilheira, e a leste por rochas ígneas e sedimentares do Sistema Famatina. A descrição litológica e a análise estrutural das rochas da Sierra de Umango possibilitaram propor um modelo de evolução estrutural para a região. Seis unidades geológicas foram diferenciadas: i- unidade do embasamento de idade mesoproterozóica, Ortognaisses Juchi, ii- Unidades Metassedimentares Tambillo e iii- Tambillito, iv- Granito El Peñon, Ordoviciano sincolisional, v- Unidade de Rochas Metabásicas El Cordobés, vi- granitos tardi a póscolisionais Los Guandacolinos e Cerro Veladero. No evento tectônico colisional Ordoviciano, caracterizado por um sistema de nappes e zonas de cisalhamento, foram reconhecidas três fases deformacionais (D1, D2 e D3). A fase D1 corresponde provavelmente ao estágio do metamorfismo progressivo, D2 apresenta condições P-T próximas ao pico metamórfico e a fase D3, de dobras apertadas a recumbentes com foliação plano-axial S3, freqüentemente associada a falhas inversas, registra o estágio retrogressivo do metamorfismo. A estrutura metamórfica principal das rochas é uma foliação de transposição S2, ou uma foliação milonítica. Relíquias de foliação S1 são reconhecidas, principalmente, em núcleos de porfiroblastos intercinemáticos de granada e estaurolita, sugerindo a progressão contínua das fases D1 e D2. O metamorfismo ordoviciano alcançou condições de fácies anfibolito superior a granulito em regimes de média a alta pressão. A estrutura está caracterizada por klippen dos Ortognaisses Juchi sobre a Unidade Tambillo, transportadas para S-SW e limitada, a oeste, por uma zona de cisalhamento lateral dextral (Zona de Cisalhamento Cerro Cacho - Puntilla), como rampa lateral. Esse quadro estrutural está relacionado à colisão oblíqua do Terreno Cuyania, subductado sob a protomargem de Gondwana. O sentido de subducção para NE foi inferido com base na cinemática de extrusão sinmetamórfica, registrada nas nappes (topo para S-SW) e na Zona de Cisalhamento Cerro Cacho - Puntilla. Pelo menos dois eventos posteriores deformaram as estruturas pré-existentes. A fase deformacional D4 corresponde a um dobramento normal, com comprimento de onda na ordem de 10 km, orientado N-S. São dobras cilíndricas que deformaram a foliação S2 e associam-se a zonas de cisalhamento discretas. O padrão cilíndrico e os eixos subhorizontais das dobras D4 pressupõem a orientação horizontal a subhorizontal para as estruturas pré-existentes, principalmente S2. As dobras D4 são responsáveis pela preservação sinformal das klippen Juchi e Água La Falda. A foliação, em estado sólido, presente no Granito Los Guaundacolinos é paralela ao plano axial destas dobras. Essa deformação corresponde à tectônica Chanica, na interface entre o Devoniano e o Carbonífero. Dobras D5, de eixo com orientação E-W, deformam o conjunto das estruturas e podem estar vinculadas ao soerguimento durante o Ciclo Andino. / The Sierra de Umango is located at the occidental portion of La Rioja Province, northwestern Argentina. It is part of basement blocks, uplifted and rotated in the Cenozoic times, called Western Sierras Pampeanas. This region is situated in the Pampean Flat-slab of the Central Andes. Meta-igneous rocks of grenvillian mesoproterozoic age and metasedimentary units metamorphosed in the Ordovician times, characterize the Western Sierras Pampeanas. These rocks are interpreted as a part of Cuyania Composite Terrane. In the region of the Sierra de Umango, the Western Sierras Pampeanas are limited on the west by Devonian sedimentary rocks of Precordillera, and by igneous and sedimentary rocks of Famatina System on the east. The lithological description and structural analysis of rocks from Sierra de Umango enable to propose a structural evolution model for the region. Six geological units were distinguished: i- the basement unit Juchi Ortogneisses of mesoproterozoic age, iimetasedimentary units Tambillo and iii- Tambillito, iv- Ordovician sin-collisional El Peñon Granite, v- El Cordobés metamafic rocks unit; vi- late to post-collisional Los Guandacolinos and Cerro Veladero granites. The Ordovician collisional event is characterized by a nappe system and shear zones, and the rocks affected by this event show three deformational phases (D1, D2 and D3). D1 phase corresponds probably to the progressive metamorphic stage; D2 exhibits P-T conditions close to metamorphic peak; and D3 phase, of tight to recumbent folds with S3 axial plane foliation which is often related to thrust faults, records the retrogressive metamorphic stage. The main metamorphic structure of Umango´s rocks is a transposition foliation S2 or a mylonitic foliation. The relics of S1 are recognized, mainly, in cores of interkinematics porphyroblasts of garnet and staurolite, suggesting a continuous progression from D1 to D2. The Ordovician metamorphism reached granulite to upper amphibolite facies conditions in a medium to high pressure regime. The general structure is characterized by Juchi Ortogneisses klippen which was overthrust onto Tambillo Unit, in a S-SW sense, and it is limited, on west, by a right lateral shear zone (Cerro Cacho - Puntilla Shear Zone), as a lateral ramp. This structural pattern is related to the oblique collision of Cuyania Terrane, subducted underneath to the proto-Andean margin of Gondwana. The subduction sense to NE was inferred from the sin-metamorphic extrusion, registered on the nappes (top to S-SW) and on the Cerro Cacho - Puntilla Shear Zone. At least two latest events deformed the earlier structures. The D4 deformacional phase corresponds to a normal folding, with wavelenght at about 10 km, with N-S orientation. They are cylindrical folds which modified de S2 surface and are associated to discrete shear zones. The cylindrical pattern and the subhorizontal axes of the D4 folds presuppose that S2 were, originally, flat-lying surfaces. D4 folds are responsible for preserving the sinformal Juchi and Água La Falda klippen. The solid state foliation described in the Los Guandacolinos Granite is parallel to the D4 axial planes. This deformation corresponds to the Chanica Tectonic, on the interval between Devonian and Carboniferous times. D5 folds, with E-W oriented axes, deform the structures set and could be associated with the uplifting during the Andean Cycle.

As sub-bacias Rincón Blanco e Cerro Puntudo são depocentros pertencente à parte norte da Bacia de Cuyo, que está exposta em um terreno alóctone da Pre- Cordilheira, Andes Centrais, Argentina. Este terreno é descrito como parte do Supercontinente Laurentia, que foi adicionado ao protomargin Gondwana durante o Oroviciano. A bacia, que é um rifte Triássico, foi preenchida predominantemente de sedimentos clásticos e material vulcânico, vulcanclástico e piroclástico em ambiente continental, e é composta de vários meio-grabens assimétricos conectados por zonas de acomodação. Análises isotópicas de UPb e Lu-Hf em zircão foram realizadas nas unidades do embasamento, rochas vulcanoclásticas rochas e tufos de ambas as sub-bacias triássicas. O embasamento, representado por rochas vulcânicas andesíticas, foi datado em 269,9 ± 2,9 Ma com idades modelo de Hf de 1,34 a 1,60 bilhões de anos (Ga). As rochas vulcanoclásticas são compostas por zircões com idades de 238 a 1433 milhões de anos (Ma), com moda principal no Permiano-Triássico e Esteniano (1,0 a 1,2 Ga). Riolito e tufos triássicos formaram-se entre 246 e 230 Ma e têm idades modelo Hf variando de 1,02 a 1,50 Ga. Assim, as rochas vulcanoclásticas presentes apresentam dominantemente idades mesoproterozóicas, as quais são correlacionados ao Evento Grenviliano. Alguns grãos de zircão mostram idades modelo Hf paleoproterozóicas, que são interpretadas como sugestiva proveniência do Supercontinente Gondwana. A presença de idades mesoproterozoica dominante sugere que o magmatismo ácido associado a Bacia do Cuyo e o próprio Terreno Alóctono Cuyano tenha um embasamente Grenviliano. / The sub-basins Rincón Blanco and Cerro Puntudo are depocenter belonging to the northern part of the Cuyo Basin, exposed in an allochthonous terrane of Laurentia that was added to the Gondwana protomargin and now exposed in the Precordillera Argentina. The rift basin was filled predominantly of pyroclastic and continental clastic sediments, and is composed of many asymmetric grabens half-linked by accommodation zones. U-Pb and Lu-Hf zircon isotope analyses were carried out in the basement units and volcanoclastic rocks and tuffs of both Triassic sub-basins. Basement rocks were dated at 269.9±2.9 Ma with Hf model ages 1.34 to 1.60 Ga. The volcanoclastic rocks contain zircons crystallized from 238 Ma to 1433 Ma with main peak at Permian-Triassic and Stenian (1.0 to 1.2 Ga). The Triassic rhyolite and tuffs formed between 246 and 230 Ma and have Hf model ages ranging from 1.02 to 1.50 Ga. Indeed, the volcanoclastic rocks present dominant Mesoproterozoic ages, mostly correlated to the Grenvillian. Some zircon grains show Hf Paleoproterozoic model ages which are interpreted to be part of Gondwana cratonic areas. The presence of dominant Mesoproteorzoic favored the hypotheses of a Grevillian basement for the related acid magmatism of the Cuyo Basin and allocthonous Cuyan Terrane.

La Cordillère des Andes, issue de la subduction de la plaque Pacifique sous le continent Sud-Américain, est un système orogénique propice à la formation de grands systèmes volcaniques acides, dans lesquels coexistent des produits d’éruptions volcaniques explosives de grandes magnitudes et des laves et dômes, associés à des calderas mono- ou polygéniques. Ce mémoire de thèse apporte de nouvelles connaissances sur certains systèmes volcaniques acides du Sud du Pérou, dont les produits affleurent dans les canyons d’Ocoña-Cotahuasi-Maran (OCM). Ces canyons, les plus profonds des Andes (3 à 3,5 km), résultent de la combinaison des processus de soulèvement tectonique, d’incision, et d’érosion depuis 15 Ma. Les imposantes séries ignimbritiques exposées dans cette région (env. 10000 km²), témoignent de l’existence d’un volcanisme explosif de grande ampleur, associé à des systèmes acides peu connus d’après les études antérieures. Cette étude vise tout d’abord à obtenir une chrono-stratigraphie améliorée des événements ignimbritiques (groupes, unités) dans la région OCM pour mieux connaître les récurrences des super-éruptions dans cette région au cours des derniers 25 Ma. Ensuite, nous cherchons à localiser les sources des grandes unités et à identifier les éventuelles structures d’effondrement associées (calderas). Pour ce faire, nous avons combiné diverses techniques, associant l’étude de la stratigraphie et de la lithologie des dépôts volcaniques, les datations par la méthode 40Ar-39Ar des principales unités ignimbritiques et coulées de lave, l’imagerie satellitaire (Landsat, SPOT) et la pétrologie (assemblages minéralogiques, étude des textures et des compositions chimiques) et enfin, les mesures de densité et d’anisotropie de susceptibilité magnétique des ignimbrites (ASM) pour analyser les directions d’écoulement et tenter de localiser leurs sources. Ainsi, les résultats nous ont permis d’identifier huit événements ignimbritiques, dont six majeurs, datés entre ~24 Ma et ~2 Ma. Les âges des grandes unités (Nazca, Alpabamba, Huaylillas, Caraveli, Sencca inférieure et supérieure) montrent une récurrence moyenne de l’ordre de 4-5 Ma depuis 25 Ma. Les lithologies sont assez semblables, bien que les degrés de soudure varient beaucoup, allant de produits meubles jusqu’aux faciès eutaxitiques. L’étude pétrologique révèle des assemblages de minéraux assez homogènes, les paragenèses étant dominées par le quartz, le feldspath, la biotite, l’amphibole et des oxydes. Les volumes bruts des unités principales que nous avons déterminés se situent entre ~40 et ~500-800 km3. Cependant, il ne s’agit que de valeurs minimales, puisque nous considérons que les volumes initiaux sont au moins le double ou le triple, probablement dans la gamme ~100 à ~2400 km3. La distribution des unités ignimbritiques d’OCM et les résultats des analyses ASM désignent plusieurs zones sources. L’unité de Caraveli provient de la caldera de Trapiche, qui contient le lac Parinacochas. Cette structure que nous identifions, d'un diamètre de ~22 km, est située dans un bassin tectonique allongé selon la direction N-S. Elle est occupée dans sa partie ouest par un dôme résurgent de 800 m de haut, le Cerro Trompo Orjo. Les unités Huaylillas et Alpabamba, ainsi que les groupes Sencca (inférieure et supérieure) seraient issus d’une source entièrement recouverte par le massif volcanique quaternaire du Nevado Coropuna. Des estimations de volumes éruptifs suggèrent une atténuation significative du volcanisme ignimbritique depuis 9 Ma, peut-être liée à la maturation orogénique de l’Altiplano-Puna. En profondeur, le magmatisme a probablement contribué à l’épaississement crustal par adjonction de grands volumes de magma. (...) / The Andes, resulting from the subduction of Pacific plate under South-America continental plate, is an orogenic system suitable for large acidic volcanic systems formation. These structures display at the same time volcanic products from high magnitude explosive eruptions, lavas and domes, and mono- or polygenetic calderas. This manuscript brings a new expertise on some of the acidic volcanic systems in South Peru, which products outcrop in the Ocoña - Cotahuasi - Maran canyons (OCM). This canyons system, one of the deepest worldwide (up to 3.5 km), was created by combined tectonic uplift, incision and erosion processes since 15 Ma. Voluminous ignimbritic series widespread in this region (around 10000 km2) are evidences for a past high amplitude explosive volcanic activity related to little-known acidic systems. The topic of this study is to obtain an enhanced chrono-stratigraphy of the OCM region ignimbritic succession (groups and units). This would provide a better knowledge on the regional super-eruptions recurrence since the last 25 Ma. Then, we focus on localizing the largest ignimbrites sources and identify the possible related collapse structures (calderas). For that purpose we combine several studies, from stratigraphy, deposits lithology to 40Ar-39Ar dating of the main ignimbritic units and lava flows. We also use satellite imagery (Landsat, SPOT) and petrology (mineralogical assemblage, textures and geochemical composition). Finally, we measure the ignimbrites density and anisotropy of magnetic susceptibility (AMS) to determine their flowing directions and estimate their sources locations. Thus, the results let us identify eight ignimbritic events among which, six happened between ~24 Ma and ~2 Ma. The main units ages (Nazca, Alpabamba, Huaylillas, Caraveli, lower and upper Sencca) show an average recurrence of 4-5 Ma since 25 Ma. Lithologies are similar even if welding degrees ranges are spread from loose deposits to eutaxitic facies. Petrological study show quite homogeneous mineralogical assemblages since quartz, feldspar, biotite, amphibole and oxydes dominate the paragenesis. Our estimations of the main units bulk volumes range from ~ 40 to ~ 500-800 km3. However, these are only minimum values since we consider that initial volumes as twice or three times higher, probably in the range of ~100 to ~2400 km3. The OCM ignimbrite flow units distribution and the AMS study results indicate several regions as sources for these units. Caraveli unit flowed from Trapiche caldera in which the Parinacochas lake rests. This structure is estimated to be ~22 km of diameter and lays in a N-S orientated tectonic basin. Its western part is occupied with a 800 m high resurgent dome, named Cerro Trompo Orjo. Alpabamba and Huaylillas units, as Sencca units (lower and upper) would come from a source presently entirely covered with the quaternary massif of Nevado Coropuna. Estimations of eruptive volumes recall an important decrease of ignimbritic volcanism since 9 Ma, which might be related to simultaneous Altiplano-Puna orogenic growing. It is supported that deep magmatism have probably contributed to crustal thickening thanks to the addition of large volumes of magma. These results also involve that canyons erosion and incision would have taken place at a rate ranging from 150 to 500 m/Ma during the last 13 Ma. Given that the large-volume acidic system studied in this work is considerable, further research are necessary to improve these results.