Kurt Rademaker | Texas A&M University (original) (raw)
Papers by Kurt Rademaker
The Oxford Handbook of Mountain Archaeology, 2024
The American Cordillera comprises a system of mountains stretching nearly 15,000 kilometres from ... more The American Cordillera comprises a system of mountains stretching nearly 15,000 kilometres from the Alaska and Brooks Ranges in the north to the southernmost tip of South America at Tierra del Fuego. In a rather real way, the Cordillera constitutes a backbone for the Western Hemisphere. Within
the American Cordillera, the North American Rocky Mountains and South American Andes contain some of the earliest widely accepted sites in the hemisphere and played an important role in the initial peopling of the Americas. Recent research in the Rockies and Andes focusses on the development of physiological and genetic adaptations to high elevation, the time frames of initial and intensified residential occupation of highlands, the nature of connections between early highland and lowland sites, and potential use of the American Cordillera as an early migration corridor. Such research reveals a very early (Late Pleistocene and Early Holocene) command of high-altitude landscapes and their resources and highly flexible settlement and mobility strategies.
Latin American Antiquity, 2024
During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and dista... more During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari’s Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa.
Quaternary International, 2024
In 2013 archaeological radiocarbon databases covering 13,000–7000 14C BP for nine countries in So... more In 2013 archaeological radiocarbon databases covering 13,000–7000 14C BP for nine countries in South America, including Peru, were published in a special issue of Quaternary International. The past decade has seen new field research and radiocarbon ages contributed to the Peruvian archaeological record, two updates to the southern hemisphere calibration curve, and research papers drawing from South American radiocarbon databases to explore region- and continent-scale patterns of human-environment interaction, settlement dynamics, and paleodemography.
This paper provides an update to the Peruvian archaeological radiocarbon database for the Late Pleistocene to early Middle Holocene. The new database (version 2) includes 493 radiocarbon dates spanning 20,000 to 7000 14C BP. No radiocarbon dates >13,000 14C BP meet basic archaeological criteria. First, I review the structure of Peru’s early archaeological radiocarbon record and highlight several research and landscape taphonomic biases. Second, I examine distributions of archaeological sites through time, beginning with basic site and date frequencies and progressing to Bayesian analysis of aggregated radiocarbon dates. Third, applying established criteria for well-dated archaeological events, I identify some unresolved problems in early Peruvian radiocarbon
chronologies, with the goal of outlining priorities for future archaeological and chronometric research.
Quaternary Science Reviews
The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence... more The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence for fire can be expected in high-latitude and high-elevation regions successfully inhabited by modern humans. At Cuncaicha rockshelter (4480 m above sea level, or masl) in the southern Peruvian Andes, evidence for fire is present from the earliest occupation, dating to the Terminal Pleistocene (∼12,500–11,200 cal BP). Yet, the site contains relatively few identifiable carbonized macrobotanical remains useful for identifying plants employed as combustible fuel. Based on a comprehensive review of nearly 40 early Andean archaeological sites above 2500 masl, little is known about fuels used for combustion. To understand fuel selection strategies at Cuncaicha, we conducted a combustion field experiment, evaluating the three highland plant taxa most likely to have been used as combustible fuels: Polylepis rugulosa (queñua) tree branches, Parastrephia spp. (tola) woody shrubs, and Azorella compacta (yareta) cushion plants. Temperature measurements informed on the combustion characteristics and efficiency of each fuel. We then compared the experimentally-produced fire residues to the geoarchaeological evidence from Cuncaicha. The resinous cushion plant yareta, endemic to the high Andes, may have been the primary fuel used at Cuncaicha based on the experiment outcome and the geoarchaeological evidence. Due to its high-temperature and complete combustion, yareta leaves little to no macrobotanical evidence, thus its identification at other Andean sites may require a multi-methodological approach. Because the geographic range of this plant corresponds with most early archaeological sites in the high Andes, yareta may have been a key resource enabling early settlement throughout the region.
Quaternary Science Reviews, 2023
The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence... more The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence for fire can be expected in high-latitude and high-elevation regions successfully inhabited by modern humans. At Cuncaicha rockshelter (4480 m above sea level, or masl) in the southern Peruvian Andes, evidence for fire is present from
the earliest occupation, dating to the Terminal Pleistocene (~12,500–11,200 cal BP). Yet, the site contains relatively few identifiable carbonized macrobotanical remains useful for identifying plants employed as combustible fuel. Based on a comprehensive review of nearly 40 early Andean archaeological sites above 2500 masl, little is known about fuels used for combustion. To understand fuel selection strategies at Cuncaicha, we conducted a combustion field experiment, evaluating the three highland plant taxa most likely to have been used as combustible fuels: Polylepis rugulosa (quenua) tree branches, Parastrephia spp. (tola) woody shrubs, and Azorella compacta (yareta) cushion plants. Temperature measurements informed on the combustion characteristics and efficiency of each fuel. We then compared the experimentally-produced fire residues to the geoarchaeological evidence from Cuncaicha. The resinous cushion plant yareta, endemic to the high Andes, may have been the primary fuel used at Cuncaicha based on the experiment outcome and the geoarchaeological evidence. Due to its high-temperature and complete combustion, yareta leaves little to no macrobotanical evidence, thus its identification at other Andean sites may require a multi-methodological approach. Because the geographic range of this plant corresponds with most early archaeological sites in the high Andes, yareta may have been a key resource enabling early settlement throughout the region.
Journal of Geophysical Research: Earth Surface
The accelerating flux of glacial meltwater to the oceans due to global warming is a potential tri... more The accelerating flux of glacial meltwater to the oceans due to global warming is a potential trigger for future climate disturbance. Past disruption of Atlantic Ocean circulation, driven by melting of land‐based ice, is linked in models to reduced ocean‐atmosphere heat transfer and abrupt cooling during stadial events. The most recent stadial, the Younger Dryas (YD), is traditionally viewed as a severe cooling centered on the North Atlantic but with hemispheric influence. However, indications of summer warmth question whether YD cooling was truly year‐round or restricted to winter. Here, we present a beryllium‐10‐dated glacier record from the north‐east North Atlantic, coupled with 2‐D glacier‐climate modeling, to reconstruct Lateglacial summer air temperature patterns. Our record reveals that, contrary to the prevailing model, the last glacial advance in Scotland did not occur during the YD but predated the stadial, while the YD itself was characterized by warming‐driven deglaciat...
Journal of Geophysical Research - Earth Surface, 2023
The Younger Dryas (YD: 12.9-11.7 ka) is a canonical example of abrupt climate change and has evol... more The Younger Dryas (YD: 12.9-11.7 ka) is a canonical example of abrupt climate change and has evolved in interpretation from a cold snap of possibly global extent to a primarily Northern Hemisphere event centered on the North Atlantic and linked to meltwater-forced disturbance of Atlantic meridional overturning circulation (AMOC) (Broecker et al., 2010; McManus et al., 2004). Northern Hemisphere palaeoclimate data confirm the YD was accompanied by atmospheric circulation shifts (
PaleoAmerica
Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior ... more Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior to the Last Glacial Maximum (33,000-31,000 cal BP) based on the presence of purported stone tools and cutmarks on bones. We provide a summary of their research and critically evaluate these claims. We conclude that the claims of a pre-LGM occupation at AdV are unsupported due to: (1) equivocal evidence that the purported stone tools are culturally modified; (2) insufficiently documented spatial and contextual information; (3) inadequate geological research leading to an unconvincing site formation model; and (4) inadequate testing of alternative hypotheses for bones with surface modifications. We conclude that the site is best interpreted as a natural time-transgressive accumulation of mammal bones and other organic and inorganic materials within a fluvial setting spanning four millennia, and that bone surface modifications are the product of natural site formation processes rather than human agency.
PaleoAmerica, 2022
Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior ... more Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior to the Last Glacial Maximum (33,000-31,000 cal BP) based on the presence of purported stone tools and cutmarks on bones. We provide a summary of their research and critically evaluate these claims. We conclude that the claims of a pre-LGM occupation at AdV are unsupported due to: (1) equivocal evidence that the purported stone tools are culturally modified; (2) insufficiently documented spatial and contextual information; (3) inadequate geological research leading to an unconvincing site formation model; and (4) inadequate testing of alternative hypotheses for bones with surface modifications. We conclude that the site is best interpreted as a natural time-transgressive accumulation of mammal bones and other organic and inorganic materials within a fluvial setting spanning four millennia, and that bone surface modifications are the product of natural site formation processes rather than human agency.
PaleoAmerica
The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) as... more The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) assemblage from south central lower Michigan, recovered by the property owners and the lead author. Interdisciplinary analysis reveals that the locale is likely a short term but intensive discard location with an assemblage composed of unfinished and broken fluted and unfluted bifaces with almost no associated debitage. There is evidence for a hearth in the form of soil discoloration, fire-cracked rock, color and structural alteration of tool stone, and thermal fractures. Tool-stone sources are local Bayport chert as assessed through hand-specimen characteristics and portable X-ray fluorescence analyses. Microwear and protein residue analyses corroborate the use of one tool fragment for use on rabbit/hare or deer/elk. Implications of the several analyses are discussed and synthesized.
PaleoAmerica, 2022
The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) as... more The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) assemblage from south central lower Michigan, recovered by the property owners and the lead author. Interdisciplinary analysis reveals that the locale is likely a short term but intensive discard location with an assemblage composed of unfinished and broken fluted and unfluted bifaces with almost no associated debitage. There is evidence for a hearth in the form of soil discoloration, fire-cracked rock, color and structural alteration of tool stone, and thermal fractures. Tool-stone sources are local Bayport chert as assessed through hand-specimen characteristics and portable X-ray fluorescence analyses. Microwear and protein residue analyses corroborate the use of one tool fragment for use on rabbit/hare or deer/elk. Implications of the several analyses are discussed and synthesized.
Journal of Archaeological Science
Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the ... more Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the vertical ecological zones of the Central Andes in South America. Such research assumes that oxygen and hydrogen isotopes in meteoric waters demonstrate an inverse relationship with elevation. However, because the primary source of precipitation in the Central Andes is the Atlantic Ocean, this expectation is likely complicated by surface-level processes on the western Andean slope. We evaluate the spatial patterning of stable isotope values in surface waters along a coast-highland transect in southern Peru (~15-17◦S). Surface water δ18O and δ2H values in the study area are consistent with regional and global meteoric waters. However, lowland and highland surface waters demonstrate wide variability and overlapping ranges of surface water isotope values. Therefore, it is challenging to discern the origin of surface waters based on elevation alone. Rather, surface water δ18O and δ2H values appear to reflect hydrologic processes including seasonality, stream order, catchment size, and distance from the source. We identify the “Watershed Effect,” which precludes the use of δ18O and δ2H in Andean bioarchaeological studies of inter-zonal mobility. Moreover, changing hydroclimate over the Holocene and present sampling precision for biological analytes confound existing interpretations of δ18O derived from archaeological bioapatite. Given the regional complexities of δ18Owater presented here, isotopic assessments of human paleomobility require better baseline data than those currently available for the Central Andes. We contend that previous archaeological datasets using δ18Obioapatite to assess mobility between high and low elevations should be re-evaluated. Further, future studies should provide adequate baseline data to justify archaeological analyses and support subsequent interpretations.
Journal of Archaeological Science, 2022
Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the ... more Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the vertical ecological zones of the Central Andes in South America. Such research assumes that oxygen and hydrogen isotopes in meteoric waters demonstrate an inverse relationship with elevation. However, because the primary source of precipitation in the Central Andes is the Atlantic Ocean, this expectation is likely complicated by surface-level processes on the western Andean slope. We evaluate the spatial patterning of stable isotope values in surface waters along a coast-highland transect in southern Peru (~15-17◦S). Surface water δ18O and δ2H values in the study area are consistent with regional and global meteoric waters. However, lowland and highland surface waters demonstrate wide variability and overlapping ranges of surface water isotope values. Therefore, it is challenging to discern the origin of surface waters based on elevation alone. Rather, surface water δ18O and δ2H values appear to reflect hydrologic processes including seasonality, stream order, catchment size, and distance from the source. We identify the “Watershed Effect,” which precludes the use of δ18O and δ2H in Andean bioarchaeological studies of inter-zonal mobility. Moreover, changing hydroclimate over the Holocene and present sampling precision for biological analytes confound existing interpretations of δ18O derived from archaeological bioapatite. Given the regional complexities of δ18Owater presented here, isotopic assessments of human paleomobility require better baseline data than those currently available for the Central Andes. We contend that previous archaeological datasets using δ18Obioapatite to assess mobility between high and low elevations should be re-evaluated. Further, future studies should provide adequate baseline data to justify archaeological analyses and support subsequent interpretations.
Nawpa Pacha, 2022
This article reports the identification of the Sayrosa Source, a minor geologic source of volcani... more This article reports the identification of the Sayrosa Source, a minor geologic source of volcanic glass referred to Rare Type-3 obsidian in the 1977 pilot study by Burger and Asaro. Located only 25 km northeast of the major Alca-1 deposit, this source was exploited in prehispanic times despite the relatively small size of its nodules. Occasional flakes and bifaces of Sayrosa obsidian appear at archaeological sites in the puna of Chumbivilcas and the Cusco Valley probably as the by-product of llama caravans carrying other goods such as meat, wool, salt and Alca obsidian from the high grasslands of northern Arequipa to the agricultural communities of Cusco.
Este artículo presenta la identificación geológica y geoquímica de la Fuente Sayrosa, un depósito geológico de obsidiana localizado a 25 km noreste de la cantera de obsidiana Alca-1 en el Valle de Cotahuasi. La Fuente Sayrosa fue utilizada en la prehistoria por mas que un milenio a pesar que se caracteriza por nódulos pequeños de obsidiana. Cantidades menores de obsidiana provenientes de esta fuente se encuentran en sitios arqueológicos de Chumbivilcas y del Valle de Cusco, probablemente como el subproducto de las caravanas que transportaban otros materiales como carne, lana, sal y obsidiana de
las canteras de Alca-1 desde la puna al norte de Arequipa a los valles agrícolas de Cusco.
Quaternary International, 2021
The Alca obsidian source in southern Peru is one of the largest and most geochemically complex so... more The Alca obsidian source in southern Peru is one of the largest and most geochemically complex sources of volcanic glass in South America. Hunter-gatherers first discovered and used Alca obsidian for stone tools at the end of the Pleistocene. Alca later became one of the three most economically important and widely distributed sources of obsidian in the Central Andean region. Systematic mapping and geochemical characterization efforts spanning 20+ years have revealed an extensive high-elevation source region composed of six geographically and
compositionally distinct sub-sources. Here we synthesize research documenting the 2000 km2 spatial extent of the Alca obsidian source, and we present expanded geochemical datasets for six Alca sub-sources (n = 238 geologic samples) obtained using neutron activation analysis (NAA), laboratory x-ray fluorescence (XRF), and portable (p)XRF. Results for Alca and for six other obsidian sources in the Peruvian Andes illustrate the efficacy of these techniques to discriminate Peruvian obsidian sources, including Alca sub-sources. Comprehensive
compositional data from the Alca source area, examined against accumulating obsidian artifact datasets from throughout Peru, reveal past human use of various Alca sub-sources. These cases contribute fine-grained behavioral information, made possible by a complex obsidian source with geographically patterned geochemical
variation and a >12,000-year sequence of human interaction with this geologic resource.
Geoarchaeology, 2021
We report results from geoarchaeological investigations at Cuncaicha rock shelter (4480 m above s... more We report results from geoarchaeological investigations at Cuncaicha rock shelter (4480 m above sea level) in the high Andes of southern Peru. Using field observations, geomorphological, micromorphological, micro-Fourier transform infrared spectroscopy, Bayesian modeling of radiocarbon ages, and archaeological data, we analyzed the entire stratigraphic sequence to determine depositional and postdepositional processes and agents to assess the impact of bioturbation and to correlate the deposits with regional paleoenvironmental information. The archaeological record is represented well on a microscale, and bioturbation has not destroyed the stratigraphic integrity. The Terminal
PaleoAmerica, 2021
Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occ... more Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occupation in the Americas, based on lithic items excavated from Chiquihuite Cave, Zacatecas. Although they provide extensive array of ancillary studies of the cave's chronostratigraphic and paleoenvironmental record, the data they present do not support their central argument, that these lithic items are anthropogenic and represent a unique lithic industry produced by early human occupants. They give limited consideration to the most plausible alternative explanation: that the assemblage is a product of natural processes of disintegration, roof fall, and mass movement of the cave fill, and thus the lithic materials are best explained as geofacts. We assess the evidence by considering the alternative hypotheses (1) that the observed phenomena are artifacts or (2) that they result from natural processes. We conclude that hypothesis 2 is more strongly supported and that Chiquihuite Cave does not represent evidence for the earliest Americans.
PaleoAmerica, 2021
Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occ... more Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occupation in the Americas, based on lithic items excavated from Chiquihuite Cave, Zacatecas. Although they provide extensive array of ancillary studies of the cave's chronostratigraphic and paleoenvironmental record, the data they present do not support their central argument, that these lithic items are anthropogenic and represent a unique lithic industry produced by early human occupants. They give limited consideration to the most plausible alternative explanation: that the assemblage is a product of natural processes of disintegration, roof fall, and mass movement of the cave fill, and thus the lithic materials are best explained as geofacts. We assess the evidence by considering the alternative hypotheses (1) that the observed phenomena are artifacts or (2) that they result from natural processes. We conclude that hypothesis 2 is more strongly supported and that Chiquihuite Cave does not represent evidence for the earliest Americans.
PaleoAmerica, 2021
Various chronologies of the earliest Native American occupations have been proposed with varying ... more Various chronologies of the earliest Native American occupations have been proposed with varying levels of empirical support and conceptual rigor, yet none is widely accepted. A recent survey of pre-Clovis dated sites (Becerra-Valdivia and Higham 2020) concludes a pre-Last Glacial Maximum (>26,500-19,000 cal yr BP) entry of humans in the Americas, in part based on recent work at Chiquihuite Cave, Mexico. We evaluate the evidence used to develop this inference. To provide clarity, we present three explicit dispersal models for the earliest human dispersals to the Americas: Strict Clovis-First (13,050 cal yr BP), Paleoindian (<16,000 cal yr BP), and Pre-Paleoindian (>16,000 cal yr BP, encompassing pre-LGM, preferred by Becerra-Valdivia and Higham (2020)), and we summarize the current genetic and archaeological evidence bearing on each. We regard all purported Pre-Paleoindian sites as equivocal and the Strict Clovis-First model to be equally unsupported at present. We conclude that current data strongly support the Paleoindian Dispersal model, with Native American ancestors expanding into the Americas sometime after 16,000 cal yr BP (and perhaps after 14,800 cal yr BP), consistent with well-dated archaeological sites and with genetic data throughout the western hemisphere. Models of the Americas' peopling that incorporate Chiquihuite or other claimed Pre-Paleoindian sites remain unsubstantiated.
PaleoAmerica, 2021
Various chronologies of the earliest Native American occupations have been proposed with varying ... more Various chronologies of the earliest Native American occupations have been proposed with varying levels of empirical support and conceptual rigor, yet none is widely accepted. A recent survey of pre-Clovis dated sites (Becerra-Valdivia and Higham 2020) concludes a pre-Last Glacial Maximum (>26,500-19,000 cal yr BP) entry of humans in the Americas, in part based on recent work at Chiquihuite Cave, Mexico. We evaluate the evidence used to develop this inference. To provide clarity, we present three explicit dispersal models for the earliest human dispersals to the Americas: Strict Clovis-First (13,050 cal yr BP), Paleoindian (<16,000 cal yr BP), and Pre-Paleoindian (>16,000 cal yr BP, encompassing pre-LGM, preferred by Becerra-Valdivia and Higham (2020)), and we summarize the current genetic and archaeological evidence bearing on each. We regard all purported Pre-Paleoindian sites as equivocal and the Strict Clovis-First model to be equally unsupported at present. We conclude that current data strongly support the Paleoindian Dispersal model, with Native American ancestors expanding into the Americas sometime after 16,000 cal yr BP (and perhaps after 14,800 cal yr BP), consistent with well-dated archaeological sites and with genetic data throughout the western hemisphere. Models of the Americas' peopling that incorporate Chiquihuite or other claimed Pre-Paleoindian sites remain unsubstantiated.
The Oxford Handbook of Mountain Archaeology, 2024
The American Cordillera comprises a system of mountains stretching nearly 15,000 kilometres from ... more The American Cordillera comprises a system of mountains stretching nearly 15,000 kilometres from the Alaska and Brooks Ranges in the north to the southernmost tip of South America at Tierra del Fuego. In a rather real way, the Cordillera constitutes a backbone for the Western Hemisphere. Within
the American Cordillera, the North American Rocky Mountains and South American Andes contain some of the earliest widely accepted sites in the hemisphere and played an important role in the initial peopling of the Americas. Recent research in the Rockies and Andes focusses on the development of physiological and genetic adaptations to high elevation, the time frames of initial and intensified residential occupation of highlands, the nature of connections between early highland and lowland sites, and potential use of the American Cordillera as an early migration corridor. Such research reveals a very early (Late Pleistocene and Early Holocene) command of high-altitude landscapes and their resources and highly flexible settlement and mobility strategies.
Latin American Antiquity, 2024
During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and dista... more During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari’s Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa.
Quaternary International, 2024
In 2013 archaeological radiocarbon databases covering 13,000–7000 14C BP for nine countries in So... more In 2013 archaeological radiocarbon databases covering 13,000–7000 14C BP for nine countries in South America, including Peru, were published in a special issue of Quaternary International. The past decade has seen new field research and radiocarbon ages contributed to the Peruvian archaeological record, two updates to the southern hemisphere calibration curve, and research papers drawing from South American radiocarbon databases to explore region- and continent-scale patterns of human-environment interaction, settlement dynamics, and paleodemography.
This paper provides an update to the Peruvian archaeological radiocarbon database for the Late Pleistocene to early Middle Holocene. The new database (version 2) includes 493 radiocarbon dates spanning 20,000 to 7000 14C BP. No radiocarbon dates >13,000 14C BP meet basic archaeological criteria. First, I review the structure of Peru’s early archaeological radiocarbon record and highlight several research and landscape taphonomic biases. Second, I examine distributions of archaeological sites through time, beginning with basic site and date frequencies and progressing to Bayesian analysis of aggregated radiocarbon dates. Third, applying established criteria for well-dated archaeological events, I identify some unresolved problems in early Peruvian radiocarbon
chronologies, with the goal of outlining priorities for future archaeological and chronometric research.
Quaternary Science Reviews
The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence... more The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence for fire can be expected in high-latitude and high-elevation regions successfully inhabited by modern humans. At Cuncaicha rockshelter (4480 m above sea level, or masl) in the southern Peruvian Andes, evidence for fire is present from the earliest occupation, dating to the Terminal Pleistocene (∼12,500–11,200 cal BP). Yet, the site contains relatively few identifiable carbonized macrobotanical remains useful for identifying plants employed as combustible fuel. Based on a comprehensive review of nearly 40 early Andean archaeological sites above 2500 masl, little is known about fuels used for combustion. To understand fuel selection strategies at Cuncaicha, we conducted a combustion field experiment, evaluating the three highland plant taxa most likely to have been used as combustible fuels: Polylepis rugulosa (queñua) tree branches, Parastrephia spp. (tola) woody shrubs, and Azorella compacta (yareta) cushion plants. Temperature measurements informed on the combustion characteristics and efficiency of each fuel. We then compared the experimentally-produced fire residues to the geoarchaeological evidence from Cuncaicha. The resinous cushion plant yareta, endemic to the high Andes, may have been the primary fuel used at Cuncaicha based on the experiment outcome and the geoarchaeological evidence. Due to its high-temperature and complete combustion, yareta leaves little to no macrobotanical evidence, thus its identification at other Andean sites may require a multi-methodological approach. Because the geographic range of this plant corresponds with most early archaeological sites in the high Andes, yareta may have been a key resource enabling early settlement throughout the region.
Quaternary Science Reviews, 2023
The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence... more The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence for fire can be expected in high-latitude and high-elevation regions successfully inhabited by modern humans. At Cuncaicha rockshelter (4480 m above sea level, or masl) in the southern Peruvian Andes, evidence for fire is present from
the earliest occupation, dating to the Terminal Pleistocene (~12,500–11,200 cal BP). Yet, the site contains relatively few identifiable carbonized macrobotanical remains useful for identifying plants employed as combustible fuel. Based on a comprehensive review of nearly 40 early Andean archaeological sites above 2500 masl, little is known about fuels used for combustion. To understand fuel selection strategies at Cuncaicha, we conducted a combustion field experiment, evaluating the three highland plant taxa most likely to have been used as combustible fuels: Polylepis rugulosa (quenua) tree branches, Parastrephia spp. (tola) woody shrubs, and Azorella compacta (yareta) cushion plants. Temperature measurements informed on the combustion characteristics and efficiency of each fuel. We then compared the experimentally-produced fire residues to the geoarchaeological evidence from Cuncaicha. The resinous cushion plant yareta, endemic to the high Andes, may have been the primary fuel used at Cuncaicha based on the experiment outcome and the geoarchaeological evidence. Due to its high-temperature and complete combustion, yareta leaves little to no macrobotanical evidence, thus its identification at other Andean sites may require a multi-methodological approach. Because the geographic range of this plant corresponds with most early archaeological sites in the high Andes, yareta may have been a key resource enabling early settlement throughout the region.
Journal of Geophysical Research: Earth Surface
The accelerating flux of glacial meltwater to the oceans due to global warming is a potential tri... more The accelerating flux of glacial meltwater to the oceans due to global warming is a potential trigger for future climate disturbance. Past disruption of Atlantic Ocean circulation, driven by melting of land‐based ice, is linked in models to reduced ocean‐atmosphere heat transfer and abrupt cooling during stadial events. The most recent stadial, the Younger Dryas (YD), is traditionally viewed as a severe cooling centered on the North Atlantic but with hemispheric influence. However, indications of summer warmth question whether YD cooling was truly year‐round or restricted to winter. Here, we present a beryllium‐10‐dated glacier record from the north‐east North Atlantic, coupled with 2‐D glacier‐climate modeling, to reconstruct Lateglacial summer air temperature patterns. Our record reveals that, contrary to the prevailing model, the last glacial advance in Scotland did not occur during the YD but predated the stadial, while the YD itself was characterized by warming‐driven deglaciat...
Journal of Geophysical Research - Earth Surface, 2023
The Younger Dryas (YD: 12.9-11.7 ka) is a canonical example of abrupt climate change and has evol... more The Younger Dryas (YD: 12.9-11.7 ka) is a canonical example of abrupt climate change and has evolved in interpretation from a cold snap of possibly global extent to a primarily Northern Hemisphere event centered on the North Atlantic and linked to meltwater-forced disturbance of Atlantic meridional overturning circulation (AMOC) (Broecker et al., 2010; McManus et al., 2004). Northern Hemisphere palaeoclimate data confirm the YD was accompanied by atmospheric circulation shifts (
PaleoAmerica
Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior ... more Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior to the Last Glacial Maximum (33,000-31,000 cal BP) based on the presence of purported stone tools and cutmarks on bones. We provide a summary of their research and critically evaluate these claims. We conclude that the claims of a pre-LGM occupation at AdV are unsupported due to: (1) equivocal evidence that the purported stone tools are culturally modified; (2) insufficiently documented spatial and contextual information; (3) inadequate geological research leading to an unconvincing site formation model; and (4) inadequate testing of alternative hypotheses for bones with surface modifications. We conclude that the site is best interpreted as a natural time-transgressive accumulation of mammal bones and other organic and inorganic materials within a fluvial setting spanning four millennia, and that bone surface modifications are the product of natural site formation processes rather than human agency.
PaleoAmerica, 2022
Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior ... more Researchers at Arroyo del Vizcaíno (AdV), Uruguay, have argued that human occupation dates prior to the Last Glacial Maximum (33,000-31,000 cal BP) based on the presence of purported stone tools and cutmarks on bones. We provide a summary of their research and critically evaluate these claims. We conclude that the claims of a pre-LGM occupation at AdV are unsupported due to: (1) equivocal evidence that the purported stone tools are culturally modified; (2) insufficiently documented spatial and contextual information; (3) inadequate geological research leading to an unconvincing site formation model; and (4) inadequate testing of alternative hypotheses for bones with surface modifications. We conclude that the site is best interpreted as a natural time-transgressive accumulation of mammal bones and other organic and inorganic materials within a fluvial setting spanning four millennia, and that bone surface modifications are the product of natural site formation processes rather than human agency.
PaleoAmerica
The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) as... more The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) assemblage from south central lower Michigan, recovered by the property owners and the lead author. Interdisciplinary analysis reveals that the locale is likely a short term but intensive discard location with an assemblage composed of unfinished and broken fluted and unfluted bifaces with almost no associated debitage. There is evidence for a hearth in the form of soil discoloration, fire-cracked rock, color and structural alteration of tool stone, and thermal fractures. Tool-stone sources are local Bayport chert as assessed through hand-specimen characteristics and portable X-ray fluorescence analyses. Microwear and protein residue analyses corroborate the use of one tool fragment for use on rabbit/hare or deer/elk. Implications of the several analyses are discussed and synthesized.
PaleoAmerica, 2022
The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) as... more The Hipwater Locale is a small Parkhill Phase Middle Paleoindian (ca. 12,200-11,600 cal yr BP) assemblage from south central lower Michigan, recovered by the property owners and the lead author. Interdisciplinary analysis reveals that the locale is likely a short term but intensive discard location with an assemblage composed of unfinished and broken fluted and unfluted bifaces with almost no associated debitage. There is evidence for a hearth in the form of soil discoloration, fire-cracked rock, color and structural alteration of tool stone, and thermal fractures. Tool-stone sources are local Bayport chert as assessed through hand-specimen characteristics and portable X-ray fluorescence analyses. Microwear and protein residue analyses corroborate the use of one tool fragment for use on rabbit/hare or deer/elk. Implications of the several analyses are discussed and synthesized.
Journal of Archaeological Science
Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the ... more Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the vertical ecological zones of the Central Andes in South America. Such research assumes that oxygen and hydrogen isotopes in meteoric waters demonstrate an inverse relationship with elevation. However, because the primary source of precipitation in the Central Andes is the Atlantic Ocean, this expectation is likely complicated by surface-level processes on the western Andean slope. We evaluate the spatial patterning of stable isotope values in surface waters along a coast-highland transect in southern Peru (~15-17◦S). Surface water δ18O and δ2H values in the study area are consistent with regional and global meteoric waters. However, lowland and highland surface waters demonstrate wide variability and overlapping ranges of surface water isotope values. Therefore, it is challenging to discern the origin of surface waters based on elevation alone. Rather, surface water δ18O and δ2H values appear to reflect hydrologic processes including seasonality, stream order, catchment size, and distance from the source. We identify the “Watershed Effect,” which precludes the use of δ18O and δ2H in Andean bioarchaeological studies of inter-zonal mobility. Moreover, changing hydroclimate over the Holocene and present sampling precision for biological analytes confound existing interpretations of δ18O derived from archaeological bioapatite. Given the regional complexities of δ18Owater presented here, isotopic assessments of human paleomobility require better baseline data than those currently available for the Central Andes. We contend that previous archaeological datasets using δ18Obioapatite to assess mobility between high and low elevations should be re-evaluated. Further, future studies should provide adequate baseline data to justify archaeological analyses and support subsequent interpretations.
Journal of Archaeological Science, 2022
Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the ... more Oxygen isotopes are commonly applied to study archaeological human and animal mobility among the vertical ecological zones of the Central Andes in South America. Such research assumes that oxygen and hydrogen isotopes in meteoric waters demonstrate an inverse relationship with elevation. However, because the primary source of precipitation in the Central Andes is the Atlantic Ocean, this expectation is likely complicated by surface-level processes on the western Andean slope. We evaluate the spatial patterning of stable isotope values in surface waters along a coast-highland transect in southern Peru (~15-17◦S). Surface water δ18O and δ2H values in the study area are consistent with regional and global meteoric waters. However, lowland and highland surface waters demonstrate wide variability and overlapping ranges of surface water isotope values. Therefore, it is challenging to discern the origin of surface waters based on elevation alone. Rather, surface water δ18O and δ2H values appear to reflect hydrologic processes including seasonality, stream order, catchment size, and distance from the source. We identify the “Watershed Effect,” which precludes the use of δ18O and δ2H in Andean bioarchaeological studies of inter-zonal mobility. Moreover, changing hydroclimate over the Holocene and present sampling precision for biological analytes confound existing interpretations of δ18O derived from archaeological bioapatite. Given the regional complexities of δ18Owater presented here, isotopic assessments of human paleomobility require better baseline data than those currently available for the Central Andes. We contend that previous archaeological datasets using δ18Obioapatite to assess mobility between high and low elevations should be re-evaluated. Further, future studies should provide adequate baseline data to justify archaeological analyses and support subsequent interpretations.
Nawpa Pacha, 2022
This article reports the identification of the Sayrosa Source, a minor geologic source of volcani... more This article reports the identification of the Sayrosa Source, a minor geologic source of volcanic glass referred to Rare Type-3 obsidian in the 1977 pilot study by Burger and Asaro. Located only 25 km northeast of the major Alca-1 deposit, this source was exploited in prehispanic times despite the relatively small size of its nodules. Occasional flakes and bifaces of Sayrosa obsidian appear at archaeological sites in the puna of Chumbivilcas and the Cusco Valley probably as the by-product of llama caravans carrying other goods such as meat, wool, salt and Alca obsidian from the high grasslands of northern Arequipa to the agricultural communities of Cusco.
Este artículo presenta la identificación geológica y geoquímica de la Fuente Sayrosa, un depósito geológico de obsidiana localizado a 25 km noreste de la cantera de obsidiana Alca-1 en el Valle de Cotahuasi. La Fuente Sayrosa fue utilizada en la prehistoria por mas que un milenio a pesar que se caracteriza por nódulos pequeños de obsidiana. Cantidades menores de obsidiana provenientes de esta fuente se encuentran en sitios arqueológicos de Chumbivilcas y del Valle de Cusco, probablemente como el subproducto de las caravanas que transportaban otros materiales como carne, lana, sal y obsidiana de
las canteras de Alca-1 desde la puna al norte de Arequipa a los valles agrícolas de Cusco.
Quaternary International, 2021
The Alca obsidian source in southern Peru is one of the largest and most geochemically complex so... more The Alca obsidian source in southern Peru is one of the largest and most geochemically complex sources of volcanic glass in South America. Hunter-gatherers first discovered and used Alca obsidian for stone tools at the end of the Pleistocene. Alca later became one of the three most economically important and widely distributed sources of obsidian in the Central Andean region. Systematic mapping and geochemical characterization efforts spanning 20+ years have revealed an extensive high-elevation source region composed of six geographically and
compositionally distinct sub-sources. Here we synthesize research documenting the 2000 km2 spatial extent of the Alca obsidian source, and we present expanded geochemical datasets for six Alca sub-sources (n = 238 geologic samples) obtained using neutron activation analysis (NAA), laboratory x-ray fluorescence (XRF), and portable (p)XRF. Results for Alca and for six other obsidian sources in the Peruvian Andes illustrate the efficacy of these techniques to discriminate Peruvian obsidian sources, including Alca sub-sources. Comprehensive
compositional data from the Alca source area, examined against accumulating obsidian artifact datasets from throughout Peru, reveal past human use of various Alca sub-sources. These cases contribute fine-grained behavioral information, made possible by a complex obsidian source with geographically patterned geochemical
variation and a >12,000-year sequence of human interaction with this geologic resource.
Geoarchaeology, 2021
We report results from geoarchaeological investigations at Cuncaicha rock shelter (4480 m above s... more We report results from geoarchaeological investigations at Cuncaicha rock shelter (4480 m above sea level) in the high Andes of southern Peru. Using field observations, geomorphological, micromorphological, micro-Fourier transform infrared spectroscopy, Bayesian modeling of radiocarbon ages, and archaeological data, we analyzed the entire stratigraphic sequence to determine depositional and postdepositional processes and agents to assess the impact of bioturbation and to correlate the deposits with regional paleoenvironmental information. The archaeological record is represented well on a microscale, and bioturbation has not destroyed the stratigraphic integrity. The Terminal
PaleoAmerica, 2021
Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occ... more Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occupation in the Americas, based on lithic items excavated from Chiquihuite Cave, Zacatecas. Although they provide extensive array of ancillary studies of the cave's chronostratigraphic and paleoenvironmental record, the data they present do not support their central argument, that these lithic items are anthropogenic and represent a unique lithic industry produced by early human occupants. They give limited consideration to the most plausible alternative explanation: that the assemblage is a product of natural processes of disintegration, roof fall, and mass movement of the cave fill, and thus the lithic materials are best explained as geofacts. We assess the evidence by considering the alternative hypotheses (1) that the observed phenomena are artifacts or (2) that they result from natural processes. We conclude that hypothesis 2 is more strongly supported and that Chiquihuite Cave does not represent evidence for the earliest Americans.
PaleoAmerica, 2021
Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occ... more Archaeologists working in Mexico recently claimed evidence for pre-Last Glacial Maximum human occupation in the Americas, based on lithic items excavated from Chiquihuite Cave, Zacatecas. Although they provide extensive array of ancillary studies of the cave's chronostratigraphic and paleoenvironmental record, the data they present do not support their central argument, that these lithic items are anthropogenic and represent a unique lithic industry produced by early human occupants. They give limited consideration to the most plausible alternative explanation: that the assemblage is a product of natural processes of disintegration, roof fall, and mass movement of the cave fill, and thus the lithic materials are best explained as geofacts. We assess the evidence by considering the alternative hypotheses (1) that the observed phenomena are artifacts or (2) that they result from natural processes. We conclude that hypothesis 2 is more strongly supported and that Chiquihuite Cave does not represent evidence for the earliest Americans.
PaleoAmerica, 2021
Various chronologies of the earliest Native American occupations have been proposed with varying ... more Various chronologies of the earliest Native American occupations have been proposed with varying levels of empirical support and conceptual rigor, yet none is widely accepted. A recent survey of pre-Clovis dated sites (Becerra-Valdivia and Higham 2020) concludes a pre-Last Glacial Maximum (>26,500-19,000 cal yr BP) entry of humans in the Americas, in part based on recent work at Chiquihuite Cave, Mexico. We evaluate the evidence used to develop this inference. To provide clarity, we present three explicit dispersal models for the earliest human dispersals to the Americas: Strict Clovis-First (13,050 cal yr BP), Paleoindian (<16,000 cal yr BP), and Pre-Paleoindian (>16,000 cal yr BP, encompassing pre-LGM, preferred by Becerra-Valdivia and Higham (2020)), and we summarize the current genetic and archaeological evidence bearing on each. We regard all purported Pre-Paleoindian sites as equivocal and the Strict Clovis-First model to be equally unsupported at present. We conclude that current data strongly support the Paleoindian Dispersal model, with Native American ancestors expanding into the Americas sometime after 16,000 cal yr BP (and perhaps after 14,800 cal yr BP), consistent with well-dated archaeological sites and with genetic data throughout the western hemisphere. Models of the Americas' peopling that incorporate Chiquihuite or other claimed Pre-Paleoindian sites remain unsubstantiated.
PaleoAmerica, 2021
Various chronologies of the earliest Native American occupations have been proposed with varying ... more Various chronologies of the earliest Native American occupations have been proposed with varying levels of empirical support and conceptual rigor, yet none is widely accepted. A recent survey of pre-Clovis dated sites (Becerra-Valdivia and Higham 2020) concludes a pre-Last Glacial Maximum (>26,500-19,000 cal yr BP) entry of humans in the Americas, in part based on recent work at Chiquihuite Cave, Mexico. We evaluate the evidence used to develop this inference. To provide clarity, we present three explicit dispersal models for the earliest human dispersals to the Americas: Strict Clovis-First (13,050 cal yr BP), Paleoindian (<16,000 cal yr BP), and Pre-Paleoindian (>16,000 cal yr BP, encompassing pre-LGM, preferred by Becerra-Valdivia and Higham (2020)), and we summarize the current genetic and archaeological evidence bearing on each. We regard all purported Pre-Paleoindian sites as equivocal and the Strict Clovis-First model to be equally unsupported at present. We conclude that current data strongly support the Paleoindian Dispersal model, with Native American ancestors expanding into the Americas sometime after 16,000 cal yr BP (and perhaps after 14,800 cal yr BP), consistent with well-dated archaeological sites and with genetic data throughout the western hemisphere. Models of the Americas' peopling that incorporate Chiquihuite or other claimed Pre-Paleoindian sites remain unsubstantiated.
The 84th Annual Meeting of the Society for American Archaeology, 2019
AGU Fall Meeting Abstracts, Dec 1, 2017
AGU Fall Meeting Abstracts, Dec 1, 2012
The 82nd Annual Meeting of the Society for American Archaeology, 2018
The 81st Annual Meeting of the Society for American Archaeology, 2017
The 81st Annual Meeting of the Society for American Archaeology, 2017
The 81st Annual Meeting of the Society for American Archaeology, 2016
The 80th Annual Meeting of the Society for American Archaeology, 2015
Archaeopress Archaeology eBooks, 2022
Latin American Antiquity, 2024
During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and dista... more During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari's Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa.
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Durante el Horizonte Medio (600–1000 dC), la obsidiana fue transportada en cantidades y distancias nunca antes vistas en los Andes Centro Sur, debido en parte, al expansionista estado Wari. Dos de las tres principales fuentes de obsidiana utilizadas están en Arequipa, Perú, región de intensa influencia Wari. Sin embargo, se sabe poco del uso regional de la obsidiana. Se analizan aquí 383 artefactos de obsidiana recuperados de 10 sitios arqueológicos en Arequipa, utilizando fluorescencia de rayos X portátil (pXRF) y espectrometría de masas con plasma de acoplamiento inductivo por ablación láser (LA-ICP-MS). Los resultados destacan los patrones diacrónicos y espaciales del uso de obsidiana, las redes de intercambio y la participación local dentro del reino Wari. También indican una amplia variedad de fuentes geológicas de obsidiana, incluyendo algunas no locales, originarias del corazón de Wari en Ayacucho. A fines del Horizonte Medio, Wari había consolidado el uso exclusivo de obsidianas Alca-1 y Alca-4 (fuentes de mayor tamaño y calidad de la zona). Aquí evaluamos modelos de obtención e intercambio de obsidiana relacionados con la economía política estatal, la actividad caravanera y el papel de los centros ceremoniales/tambos que facilitaron el flujo de ideas, bienes y personas a través de Arequipa.