Daniel H. Sandweiss

Geoarchaeological Evidence from Peru for a 5000 Years B.P. Onset of El Niño

For the tropical west coast of South America, where El Niño/Southern Oscillation (ENSO) is most pronounced, archaeological and associated paleontological deposits in northern Peru revealed a major climate change at about 5000 years before the present (yr B.P.). The data implied the presence of stable, warm tropical water as far south as 10°S during the early mid-Holocene (about 8000 to 5000 yr B.P.). These data suggest that ENSO did not occur for some millennia preceding 5000 yr B.P., when global and regional climate was warmer than today.

Variation in Holocene El Niño frequencies: Climate records and cultural consequences in ancient Peru

Analysis of mollusks from archaeological sites on the north and central coasts of Peru indicates that between ca. 5800 and 3200–2800 cal yr B.P., El Nino events were less frequent than today, with modern, rapid recurrence intervals achieved only after that time. For several millennia prior to 5.8 ka, El Nino events had been absent or very different from today. The phenomena called El Nino have had severe consequences for the modern and colonial (historically recorded) inhabitants of Peru, and El Nino events also influenced prehistoric cultural development: the onset of El Nino events at 5.8 ka correlates temporally with the beginning of monumental temple construction on the Peruvian coast, and the increase in El Nino frequency after 3.2–2.8 ka correlates with the abandonment of monumental temples in the same region.

Terminal Pleistocene through Mid-Holocene archaeological sites as paleoclimatic archives for the Peruvian coast

Abstract Along the Peruvian coast, standard paleoclimatic archives such as pollen cores or corals are absent or undeveloped. However, anthropogenic deposits offer paleoclimatic information for the last 13 000 years at temporal scales ranging from centennial for long-term records to seasonal for short-term records. This paper summarizes archaeologically based paleoclimatic data for the Peruvian coast from the Terminal Pleistocene through the Middle Holocene. South of 12°S, coastal waters have been cool–temperate and terrestrial conditions have been hyperarid for the entire period. Between 8000 and 3600 cal BP, the highland precipitation supplying runoff to the south coast may have diminished sufficiently to restrict human occupation of ephemeral streams. North of ∼10°S, sea surface temperatures were warmer and seasonal precipitation may have been greater from prior to 13 000 to 5800 cal BP. From 9000 to 5800 cal BP, El Nino was absent or very infrequent. After 5800 cal BP, the northern coastal waters cooled and El Nino was present but with a lower frequency than seen in the historical and instrumental record. El Nino frequencies in the modern and historical range were established ∼3000 cal BP. Cultural changes correlate temporally with these major climatic transitions.

Early maize agriculture and interzonal interaction in southern Peru

Over the past decade, increasing attention to the recovery and identification of plant microfossil remains from archaeological sites located in lowland South America has significantly increased knowledge of pre-Columbian plant domestication and crop plant dispersals in tropical forests and other regions. Along the Andean mountain chain, however, the chronology and trajectory of plant domestication are still poorly understood for both important indigenous staple crops such as the potato (Solanum sp.) and others exogenous to the region, for example, maize (Zea mays). Here we report the analyses of plant microremains from a late preceramic house (3,431 ± 45 to 3,745 ± 65 14C bp or ∼3,600 to 4,000 calibrated years bp) in the highland southern Peruvian site of Waynuna. Our results extend the record of maize by at least a millennium in the southern Andes, show on-site processing of maize into flour, provide direct evidence for the deliberate movement of plant foods by humans from the tropical forest to the highlands, and confirm the potential of plant microfossil analysis in understanding ancient plant use and migration in this region.

Paleoindian settlement of the high-altitude Peruvian Andes

Mountain dwellers of the Pleistocene Humans colonized the inhospitable high Andes at least 11.5 thousand years ago. Rademaker et al. unearthed evidence of hunter-gatherer occupation at heights of almost 4500 m in Peru in two open-air sites. The sites contained more than 750 tools, including likely spearheads and scrapers. A nearby rockshelter with sooted ceilings and floor detritus may have been a campsite. The sites were probably used seasonally for hunting vicuña and other high-altitude prey. Science, this issue p. 466 Artifacts and rock shelters indicate hunter-gatherer presence at ~4500 meters above sea level, 12.8 to 11.5 thousand years ago. Study of human adaptation to extreme environments is important for understanding our cultural and genetic capacity for survival. The Pucuncho Basin in the southern Peruvian Andes contains the highest-altitude Pleistocene archaeological sites yet identified in the world, about 900 meters above confidently dated contemporary sites. The Pucuncho workshop site [4355 meters above sea level (masl)] includes two fishtail projectile points, which date to about 12.8 to 11.5 thousand years ago (ka). Cuncaicha rock shelter (4480 masl) has a robust, well-preserved, and well-dated occupation sequence spanning the past 12.4 thousand years (ky), with 21 dates older than 11.5 ka. Our results demonstrate that despite cold temperatures and low-oxygen conditions, hunter-gatherers colonized extreme high-altitude Andean environments in the Terminal Pleistocene, within about 2 ky of the initial entry of humans to South America.

Environmental change and economic development in coastal Peru between 5,800 and 3,600 years ago

Between ≈5,800 and 3,600 cal B.P. the biggest architectural monuments and largest settlements in the Western Hemisphere flourished in the Supe Valley and adjacent desert drainages of the arid Peruvian coast. Intensive net fishing, irrigated orchards, and fields of cotton with scant comestibles successfully sustained centuries of increasingly complex societies that did not use ceramics or loom-based weaving. This unique socioeconomic adaptation was abruptly abandoned and gradually replaced by societies more reliant on food crops, pottery, and weaving. Here, we review evidence and arguments for a severe cycle of natural disasters—earthquakes, El Niño flooding, beach ridge formation, and sand dune incursion—at ≈3,800 B.P. and hypothesize that ensuing physical changes to marine and terrestrial environments contributed to the demise of early Supe settlements.

Early Fishing Societies in Western South America

Over the past decade, archaeologists have redefined the age and complexity of early fishing societies of the Pacific coast of South America, resulting in a paradigm shift for the entire New World driven primarily by Andean research. Like most breakthroughs, the new paradigm builds on deep roots in Andean archaeology, stretching back at least to the pioneering research of Junius Bird in northern Chile and northern Peru in the 1930s and 1940s, and continuing from the 1950s to the 1990s with the work of Frederic Engel, Edward Lanning, Michael Moseley, James B. Richardson III, Agustin Llagostera, Robert Benfer, and others (see details below). Some, in particular Richardson and Llagostera, astutely recognized the true antiquity of Andean maritime adaptations from scattered and inconclusive data, and Richardson (1981) figured out why the data were so scant (particular sectors of ancient shorelines were inundated as sea level rose with deglaciation from 21,000-5800 cal yr BP; see Chapter 6 in this volume). His work has informed all subsequent research on this issue. The simultaneous publication in 1998 of two Terminal Pleistocene, Paleoindian-age fishing sites in southern Peru demonstrated conclusively that fishing is very nearly as old in the New World as the presence of humans (Sandweiss et al. 1998; Keefer et al. 1998). Why is it important whether or not some of the first settlers of the New World knew how to fish? In a seminal review of the anthropology of fishing, James Acheson (1981: 277) wrote, “fishing poses some very unusual constraints and problems. Marine adaptations are one of the most extreme achieved by man”. Among other factors that together contribute to the unique nature of such adaptations, Acheson noted human beings’ lack of physiological adaptation to aquatic environments, physical and social risk, non-transferability of most terrestrial hunting technology, high degree of faunal diversity, periodic and unpredictable stock failure, low visibility of prey, and the problems of common property resources

Chapter 2 – Mid-Holocene climate and culture change in coastal Peru

Publisher Summary This chapter reviews the history of study and the current status of Mid-Holocene climatic and cultural change along the Peruvian coast, with a focus on major transitions at ca. 5800 and 3000 cal yr BP that correlate temporally with changes in El Nino Southern Oscillation (ENSO) frequency. It begins with presenting the Peruvian archaeological record of Holocene El Nino frequency variation, considering several hypotheses to explain the data. Based on the archaeological record, it is concluded that for some time prior to 5800 years ago, the coast of Peru, north of 10°S latitude, was characterized by permanent warm water. From these data, it is hypothesized that El Nino did not operate for some period before 5800 cal yr BP; after that time, conditions as essentially the same as today were seen. Present-day climatic variability on interannual time scales in the tropics is dominated by ENSO, which involves both the atmosphere and the ocean in the tropical Pacific (e.g., Maasch, in press). Through teleconnections, extratropical climatic variability on these time scales is also impacted by ENSO. Continuous natural Holocene paleoclimate archives from northern Peru, Ecuador, and the eastern tropical Pacific Ocean are difficult to find, privileging anthropogenic deposits from archaeological sites. Although precisely dating these records is difficult, climatic change determined from them is consistent. The regional paleoclimate records are presented.

Chapter 1 – Climate and culture change: exploring Holocene transitions

Publisher Summary This chapter attempts to explore the climatic and cultural changes and transitions that have occurred in past 10,000 years. Responding successfully to climate change and its likely impacts on human culture is one of the great scientific challenges of the 21st century and a major test for global civilization. Various studies have been conducted in this regard, and various papers have been presented. This study explores how past human cultures have responded to changes in climate and consequent changes in vegetation and precipitation patterns. It documents research that offers many lessons of value to scholars, politicians/planners, and the general public. Scientific literature, archaeological research, and paleobiological evidence can be critical for identifying human presence and impact on the landscape; so, too, can geoarchaeological/geophysical analyses. Under this light, this chapter demonstrates that the reconstruction of both past climate change and past human cultural systems is best accomplished by using data from multiple sources, or proxy records, and by specialists from different disciplines working together. The development of the radiocarbon calibration curve has profound implications for archaeological and paleoenvironmental research. Furthermore, this study describes the possible causes of Holocene climate change, also rationalizing the need to study climate and culture change, and particularly events and processes occurring during the Mid-Holocene from ca. 9000 to 5000 years ago to help in the modern world. The basis for such studies lies in the relationship between climate and cultural change, which is elucidated in this chapter.

Coastal Change and Beach Ridges along the Northwest Coast of Peru: Image and GIS Analysis of the Chira, Piura, and Colan Beach-Ridge Plains

Abstract Since approximately 5200 cal yrs BP, five sets of eight to nine beach ridges were built and preserved along the northwestern Peruvian coastal desert (3°30′S–9°S). Potential ridge-building mechanisms in the hyper-arid environment of northwest Peru include El Niño floods and storms, seismic activity, and sea-level change, as well as more gradual climate changes that affected coastal morphology. Image processing and Geographic Information System (GIS) methods were used to analyze aerial photographs and measure historic coastal patterns along three beach-ridge plains over a 37-year time period. Coastal features were digitized from image mosaics of each ridge plain at different time intervals from 1946 up to 1983. Progradation rates were examined at ridge locations north of the Chira River and Piura River, as well as at the base of ephemeral stream valleys in Colán. The total change in beach area was measured from historic aerial photographs taken at different time intervals. The resulting measurements showed that sediment distributed by El Niño storms was redeposited along the shoreline within a few years following each event. The difference between the frequency of El Niño events (currently 2–7 years) and the rate of ridge preservation (1 per 500 years average) suggests that individual ridges may be composites of multiple depositional events, or that ridges result from the rare convergence of multiple processes and conditions. A change in style of ridge formation in all studied beach-ridge sets correlates with, and may be explained by, change in the frequency of El Niño events at about 3000 cal yrs BP.