image/svg+xml147 V/2/2014 INTERDISCIPLINARIA ARCHAEOLOGICA NATURAL SCIENCES IN ARCHAEOLOGY homepage: http://www.iansa.eu The Infuence of El Niño on Settlement Patterns in Lomas de Lachay, Central Coast, Peru Piotr Kalicki a* , Tomasz Kalicki b , Piotr Kittel c a Institute of Archaeology, Jagiellonian University, Gołębia street 11, 31-007 Kraków, Poland b Institute of Geography, The Jan Kochanowski University in Kielce, Świętokrzyska street 15, 25-406 Kielce, Poland c Faculty of Geographical Sciences, Department of Geomorphology and Palaeogeography, University of Lodz, Narutowicza street 88, 90-139 Łódź, Poland 1. Introduction: methodology and theory Interdisciplinary geoarcheological investigations were undertaken in Lomas de Lachay region (Central Andes, Peru). The aim of the research is the reconstruction of relations between Pre-Colombian human activity and the natural environment, particularly human adaptation strategies to the marginal ecosystem of the lomas. Archaeological survey and geomorphologic mapping with sediment sampling of the Lomas de Lachay area were conducted during the feldwork and covered about 80 km 2 .Despite the fact that archaeologists have been working in Lomas de Lachay since the beginning of the 20 th century (Villar 1935; Tello 1943; 1957; Strong and Willey 1943; Kroeber 1944) the region still remains poorly understood. Our team conducted geoarcheological research for the frst time in Lomas de Lachay which can be used to verify previous results and propose new interpretations.During the feldwork, deposits were sampled in 25 outcrops. The structural properties of the accompanying sedimentary series were recorded from the walls of the pit. 27 sediment samples for sedimentological (mainly textural) analysis and 11 for geochronological (thermoluminescence) analysis were collected. One profle will be presented below in detail.Archaeological investigations only provided the preliminary results, which should be verifed by future research. Potential archaeological sites, localized on satellite images, were verifed during the feldwork and new sites were also discovered. Relics of architecture and profles of trenches and pits left by huaqueros (grave robbers) Volume V ● Issue 2/2014 ● Pages 147–160 *Corresponding author. E-mail: kalickipiotr.krk@gmail.com ARTICLE INFO Article history: Received: 14. March 2014Accepted: 20. December 2014 Keywords: LomasLima cultureChancay cultureagriculturesettlement phasesenvironmental archaeologyInka culture ABSTRACT The Lomas de Lachay region is located about 100 kilometres north of Lima, between Río Chancay and Río Huaura valleys. It is situated approximately 10 km from the coastline, where advection fogs meet the frst ridges of the Andes allowing for the development of a peculiar ecosystem of fog oases known as lomas . Three distinct geosystems have been distinguished there: coastal desert, lomas and mountain desert.While during El Niño with episodes of ENSO the mountain desert and valleys of perennial rivers are devastated by catastrophic foods caused by torrential rains, in lomas El Niño less abundant precipitation comes about which permits the development of vegetation and also the presence of active springs during the dry season.Due to the increased availability of water in periods of frequent El Niño episodes human groups in the past were able to establish permanent settlements in the Lomas de Lachay area. When El Niño events became rare, however, only seasonal exploitation of lomas were possible. Changes in settlement pa-tterns in the research area were therefore strongly infuenced by the frequency and magnitude of El Niño events. Moreover, due to the El Niño benevolent impact, only a lomas geosystem is convenient for human activity on a larger scale, thus the majority of the archaeological sites are located within the limits of fog oases.
image/svg+xmlIANSA 2014 ● V/2 ● 147–160Piotr Kalicki, Tomasz Kalicki, Piotr Kittel: The Infuence of El Niño on Settlement Patterns in Lomas de Lachay, Central Coast, Peru 148 were documented. Diagnostic pottery sherds and other artefacts were documented. It should be emphasized that archaeological feldwork was only a survey and therefore the presented results have a preliminary character and need to be confrmed by future research. 2. Environment Lomas de Lachay (11°21′30″S; 77°22′10″W; 150–600 m a.s.l.) is situated on the western slopes of the Andes, on the frst low ridge from the coast of the Pacifc Ocean (400–1.500 m a.s.l.). The research area is located on the western coast of South America, approximately 100 km north of Lima (Figure 1).The western slopes of the Central Andes are characterized by large relief dynamics resulting from the intense tectonic uplift of the Andes (Sébrier et al. 1988). At a distance of about 100 km from the Pacifc Ocean, the main ridge of the Western Cordillera above 5.000 m a. s. l. The relief of the western slopes of the Western Cordillera developed in an extremely active tectonic regime connected with the subduction zone, with climatic changes due to the Cenozoic uplift of the Andes and sea level changes associated with the Quaternary glacial-interglacial cyclicity. The main valleys of the rivers fowing down from the mountains are separated by relatively low ridges (400–1.500 m a.s.l.), which descend directly to the Pacifc Ocean. Fluvial erosion has created a dynamic landscape with deep gorges and narrow ravines.The study area is situated within two ecological zones: the extremely dry, hot coastal desert chala (0–500 m a.s.l.) and the warm and dry yunga (500–2.300 m a.s.l.) (Pulgar Vidal 1987). The Lomas de Lachay area is characterized by an arid climate due to the infuences of the cold Humboldt Current, the orographic barrier of the Andes and the location in a low latitude zone. Dense fog from the ocean ( garúa ) is periodically deposited on the westernmost slopes of the Andean barrier during the austral winter. The frst mountain ridge acts as an orographic barrier causing condensation of the fog during the austral winter and thus allowing for the development of various ecosystems. It results in overgrowing in the area with fog-alimented seasonal oases (lomas). Two distinct seasons are particularly characteristic: 1) the humid season (from June to November) with a precipitation peak from the end of July to mid-September) and 2) the dry season (from December to May). During the humid season the relative humidity reaches 100% and average temperatures are less than 15 °C. In the summer (the dry season) the relative humidity is about 82% and average temperatures 20°C (Shoobridge 2003). Occasionally, heavy rains associated with El Niño episodes occur in the summer and allow for the development of relatively abundant vegetation during