Holocene geomorphology, tectonics, and archaeology in Barrancas, arid Central Andes piedmont (33°S) (original) (raw)
Related papers
Using an interdisciplinary perspective that integrates archaeological, geomorphological, and palynological data, this work analyzes the relationship between environmental changes and cultural landscapes in the El Bolsón Valley in the province of Catamarca, Argentina. The palynological and sedimentological studies took place using a sediment core extracted from a seasonal lake, while the geomorphological studies made use of stratified fluvial deposits. The palynological sequence indicates that wetter conditions existed at 6400 cal BP, but that this wetness decreased to create the current more arid conditions along with increases in anthropogenic disturbance. There is also evidence for intense processes of sediment accumulation and erosion, including changes in the uses of space by human populations as recorded for the last 2000 years in fine deposits from the valley floor. The present work also makes an effort to insert this local history into its broader context, in order to contribute to existing knowledge regarding late Holocene changes at the regional level.
This paper deals with the way in which the environmental dynamics that took place at the lower basin of the Colorado River (Buenos Aires province, Argentina) have affected the degree of resolution, integrity, and site preservation in different sectors of the study area (e.g.; coastal fringe, delta and interior dune fields). Evidences coming from geomorphology, stratigraphy, sedimentary, chemical parameters, and zooarchaeological assemblages are used in order to propose spatial and temporal variations in the structure of the archaeological record. The obtained results indicated that the landforms located inland that contained Initial late Holocene archaeological assemblages (3000-1000 14C years BP) have suffered important morfodinamic processes that produced site destruction, loss of organic materials and lower degrees of integrity and site resolution. Conversely, landforms placed nearby the delta and the coastal fringe underwent more stable geomorphic processes (e.g.; pedogenesis) that promoted better preservation, resolution and integrity during the Initial late Holocene and, particularly, at the Final Late Holocene (1000-250 years BP). It is proposed that the recognition of this pattern is crucial in order to evaluate demographic processes linked with the intensity of hunter-gatherers occupation of the area throughout time and population dynamics.
This paper presents a preliminary model of the occupational history of the valley bottoms at the edges of the bed of the Quequén Grande river (Argentina) during the late Holocene. The ultimate goal of the research is to situate some aspects of technology, mobility, land-use patterns and settlement systems as a proximal consequence of a long-term process of ‘lithification’, that is, the positioning of lithic raw material across otherwise lithic-free areas of the landscape. In order to address this issue, distributions of lithic artefacts are used to discuss features of the regional technological organisation and settlement systems and the relationships between people and the landscape. In that sense , lithification, a variant of a ‘provisioning places’ strategy, has implications for other aspects of a human adaptive system. The lithification process has influenced the organization of technology, in particular the degree of planning and anticipation necessary, which in turn affects the degree to which technological strategies (eg,; curation and expediency) were employed. Lithification also has implications for the organization of logistical and residential mobility strategies by encouraging reoccupations, changing periodicity of reoccupation, altering landscape use patterns, and making for longer seasonal or task-specific stays. One end result is an artificial conflation of resources, and a lessening of resource heterogeneity. For example, there will be more places where critical resources, such as water, fauna, and flora, co-occur with the lithic resources needed to exploit them. The lithic raw material distribution is only partially dependant on natural occurrence because the environment has been re-organised and (intentionally, or otherwise) built by human activity. We propose that, in the Pampas the late Holocene witnesses a process of ‘building a landscape’ which had implications for social organization and hence played an important role in regional human adaptation and cultural evolution.
. Human occupation, site formation, and chronostratigraphy of a Mid-Holocene archaeological site at the eastern Pampa-Patagonia Transition, Argentina., 2023
Intense aeolian processes in arid and semi-arid environments play an essential role in the preservation and destruction of archeological sites. This is especially the case in the lower basin of the Colorado River at the eastern Pampa-Patagonia Transition of Argentina, as is illustrated by geoarchaeological and chronostratigraphic studies at a mid-Holocene hunter-gatherer site, La Modesta, where aeolian processes strongly influence the archeological record in dune sediments. At La Modesta, surface archaeological materials are numerous and well preserved, although the stratigraphic record is incomplete. Optically stimulated luminescence (OSL) dating of sediments that contain cultural material provides a chronology dating from ca. 8.2 ka but shows one or more hiatuses from ca. 6-2 ka in the sedimentary succession. Intense morphogenesis related to arid climates likely caused gaps in sedimentation, affecting the integrity and resolution of the archaeological record. This study helps explain mid-Holocene archaeological discontinuities throughout central Argentina and highlights the importance of considering taphonomic and geologic biases when dealing with the absence or reduction of the archaeological record in dryland regions.
Over the past decade, most scholars in the field of paleoenvironmental studies have reached an agreement about the arid nature of the mid-Holocene in the South-Central Andes. However, the actual duration of arid conditions and their disparate effect in particular localities are still under discussion. This is particularly relevant in view that Mid-Holocene aridity is considered one of the main triggers of significant socio-cultural processes in the region, such as an increase in complexity among hunter-gatherers and camelid domestication. We contribute to this debate by presenting the results of a multi-proxy analisys of a 226 cm core (Cruces Core 1 or TC1) that includes geomorphology, diatoms, pollen, magnetic properties, organic matter and carbonate content of sediments. The analized record spans the late Pleistocene (i.e. 11,650 BP; ca. 13,400 cal. BP) to the onset of the Late Holocene (i.e. 4000 BP, ca. 4500 cal. BP). Results show the presence of a fluvial system that progresively lost its energy along the Holocene, turning into a wetland i.e. fluvial-palustrine landscape. Humid conditions dominated the Barrancas basin since the late Pleistocene, with a higher energy during the early Holocene and the first part of the mid-Holocene up to 6000 BP. This environment was followed by a transitional period between 6000 and 5100 BP, characterized by an unstable wetland environment fluctuating between fluvial episodes and shallow paludal and evaporitic environments. A noticeable drop in local moisture is evident from 5100 BP on. The Barrancas basin seems to have constituted a resilient habitat that alternatively offered circulation or settling possibilities for human populations throughout the Holocene, by providing dependable sources of water and prey. Its likely role as an ecological refuge even under the harshest conditions of the Holocene makes this locality highly relevant for archaeological studies.
Quaternary landscape evolution and human occupation in northwestern Argentina
Our study area is located in northwestern Argentina. It is a semiarid valley in which developed agricultural pre-Columbian settlements were located. The objectives of our research were to establish the geomorphological characteristics of the area, its relative chronological development, and the relationships between geomorphological development and pre-Columbian settlements. Pre-Quaternary lithologies are represented by a metamorphic basement that is commonly exposed on slopes and belongs to the Precambrian and Cambrian periods. Tertiary sediments from several formations are exposed over an extensive surface forming cuesta relief landforms. Quaternary landscape units were classified according to their genesis into structural–denudational landforms (denudational slopes and structural scarps), denudational landforms (covered glacis), fluvio-alluvial landforms (alluvial fans, fluvial fans, and fluvial terraces) and aeolian forms (stabilized dunes). Archaeological sites belonging to the Formative (500 BC–AD 1000) and Regional Development (AD 1000–1500) periods were identified. The main archaeological sites are located on the surfaces of debris-flow deposits and some covered glacis. They are characterized by the presence of residential units together with agricultural structures (terraces and irrigation channels). The earlier settlements (Formative period) are restricted to alluvial fan landforms (debris-flow deposits), where present hydrological supply is lower than in the rest of the study area. Later settlements (Regional Development period) are juxtaposed with earlier settlements in the south of the area, where present hydrological supply is higher owing to larger river catchments and moistureladen winds from the SE.