Thesis Chapters by Thomas J Brown
Focusing on the relationship between demography and sedentary behavior, this thesis explores chan... more Focusing on the relationship between demography and sedentary behavior, this thesis explores changes to mobility strategies on the Northern Northwest Coast of North America between 11,000 and 5,000 cal BP. Drawing on a regional database of radiocarbon dates, it uses summed probability distributions (SPDs) of calibrated dates as a proxy for population change, in combination with syntheses of previously published technological, paleo environmental and settlement pattern data to test three hypotheses derived from the literature about the development of logistic mobility among maritime hunter-gatherers on the Northern Coast. In all, each of the hypotheses proposes that early peoples on the coast were foragers that utilized high levels of residential mobility, who later adopted collector (logistic) strategies. Two of the hypotheses emphasize the role of population growth and/or packing and resource distribution in this transformation, while the third emphasizes population replacement. Other issues addressed within this thesis are whether or not the forager-collector continuum, as it is used for terrestrial hunter-gatherers, can be applied to those in aquatic settings. Also explored, is the question of whether the available data is sufficient for making and/or testing claims about early mobility patterns in the region.
The results of the demographic models suggest that while population levels were volatile, volatility declined through time and that there is no significant trend in either growth or decline of overall population levels throughout the region. This thesis also confirmed that significant changes to mobility, as evidenced by the emergence of semi-sedentary to sedentary living, begin to appear by ~7,000 cal BP. However, there appears to be little, if any correlation between the advent of more sedentary and logistic behavior and any of the variables tested here. Thus this author suggests, in agreement with Ames (1985; 2004) and Binford (2001) that the distribution of resources and labor organization needs within aquatic environments are sufficient without any other drivers for the development and intensification of logistic mobility. The principle analytic contribution of this research comes from the demographic modeling that relied on the construction of summed probability distributions. Though these methods have become commonplace in other settings (namely Europe), this thesis presents the first application of these methods within the time period and region covered. Moreover, this research is one of the only of its kind to address demographic histories within coastal landscapes that utilizes both marine and terrestrial 14C samples. In order to explore possible biases within the database, comparisons of marine and terrestrial SPDs were made between sub-sections of the region (i.e. Haida Gwaii, Southeast Alaska and the Dundas Islands). Though patterning between each of these areas was consistent, these comparative methods revealed an unexpected finding; a massive population crash throughout the region that began between ~9,000-8,800 cal BP and lasted till around 8,400 cal BP. Importantly, this crash was witnessed within all of the individual sub-areas and within SPDs made from both the marine and terrestrial 14C samples, though the reasons behind this collapse and verification of its existence require future research. However, finding this collapse at all further highlighted the need for use of correctly calibrated 14C dates, as the gap in 14C dates effectively disappears when using uncalibrated dates, which has been a longstanding tradition within Northwest archaeology.
Papers by Thomas J Brown
The Journal of Island and Coastal Archaeology, 2017
ABSTRACT Methodological advancements in geoarchaeology and spatial and chronological modeling are... more ABSTRACT Methodological advancements in geoarchaeology and spatial and chronological modeling are opening new avenues to interpreting large coastal shell-bearing sites. We document the developmental histories of two such sites around Prince Rupert Harbour, Canada, using systematic percussion coring, intensive radiocarbon dating, and 3D surface mapping with Total Station and LiDAR. We also re-analyze a third site (Boardwalk/GbTo-31) excavated and radiocarbon dated in the 1960s, 1970s, and early 2000s using archival field notes, site maps, and stratigraphic profiles georectified using LiDAR. We map the natural landform beneath the sites and document the degree to which people physically modified landforms through the deposition of massive shell accumulations. We model site development through time and space and use accumulation rates and OxCal modeling to test for intentional deposition events. All three sites demonstrate complex and heterogeneous occupation histories. At each we identify instances of very rapid deposition that effectively terraced and extended parts of the natural landform to create places for constructing houses, though these episodes take place within longer histories of slower quotidian deposition. The anthropogenic modifications to the coastline in this area are the result of these mixed processes associated with long histories of occupation.
PLOS One, 2020
The ability to distinguish between different migratory behaviours (e.g., anadromy and potamodromy... more The ability to distinguish between different migratory behaviours (e.g., anadromy and potamodromy) in fish can provide important insights into the ecology, evolution, and conservation of many aquatic species. We present a simple stable carbon isotope (δ 13 C) approach for distinguishing between sockeye (anadromous ocean migrants) and kokanee (potamodromous freshwater residents), two migratory ecotypes of Oncor-hynchus nerka (Salmonidae) that is applicable throughout most of their range across coastal regions of the North Pacific Ocean. Analyses of kokanee (n = 239) and sockeye (n = 417) from 87 sites spanning the North Pacific (Russia to California) show that anad-romous and potamodromous ecotypes are broadly distinguishable on the basis of the δ 13 C values of their scale and bone collagen. We present three case studies demonstrating how this approach can address questions in archaeology, archival, and conservation research. Relative to conventional methods for determining migratory status, which typically apply chemical analyses to otoliths or involve genetic analyses of tissues, the δ 13 C approach outlined here has the benefit of being non-lethal (when applied to scales), cost-effective, widely available commercially, and should be much more broadly accessible for addressing archaeological questions since the recovery of otoliths at archaeological sites is rare.
Journal of anthropological archaeology, 2019
Our goal is to study the role of demographic change in the development and spread of maritime ada... more Our goal is to study the role of demographic change in the development and spread of maritime adaptations in the North American Arctic over the last 6000 years. We compile and analyze a regional radiocarbon database (n = 935) for northern Alaska, using Oxcal to analyze demographic patterns in summed probability distributions. We find that northern Alaskan populations grew significantly over the last 4500 years, although growth was punctuated by three periods of decline from approximately 3700 to 3125 cal BP, 1000 cal BP, and 600 cal BP. We assess possible alternative explanations for the observed demographic patterns (e.g. calibration and taphonomic effects, investigator bias). Region-wide erosion and calibration effects likely contribute to the dearth of radiocarbon dates around 1000 cal BP, and sampling bias may contribute to the post-600 cal BP decline. However, we conclude that the overall pattern reflects regional population growth, decline, and recovery. Population growth predates intensification of marine resource procurement by at least 1200 years; we hypothesize that population growth was a possible driver for late Holocene marine intensification in the Arctic. These findings have further implications for understanding the process of intensification and the development of complexity in coastal hunter-gatherer societies.
The Journal of Island and Coastal Archaeology , 2019
The Northern Northwest Coast of North America has consistently
been an epicenter of hunter-gather... more The Northern Northwest Coast of North America has consistently
been an epicenter of hunter-gatherer research, but attention has
focused on the period after 5000 cal BP. Using data largely produced
within the past 12 years, we present the first synthesis and analysis
of this region’s 14C record between 11000 and 5000 cal BP. Our
analysis produced two primary findings (i) that the number of dated
sites does not increase or decrease significantly during this period
and (ii) there is an unexplained gap in dated sites across the entire
region between 9000 and 8300 cal BP. The existence of this gap
has critical implications regarding hypotheses of technological
change, migration, population continuity, and cultural evolution for
the region. However, available explanations for this gap are problematic.
Possible causes investigated include: demographic abandonment
of the region, distorting effects of the calibration curve, sealevel
change, taphonomy, and sampling error. All are found to
be inadequate.
American Antiquity, 2019
The late Pleistocene–early Holocene archaeological record of the interior Pacific Northwest is do... more The late Pleistocene–early Holocene archaeological record of the interior Pacific Northwest is dominated by what has been
regionally referred to as the Western Stemmed Tradition (WST). While various efforts have attempted to clarify the chronology
of this tradition, these have largely focused on data from the Great Basin and have been disproportionately preoccupied with
establishing the beginning of the tradition due to its temporal overlap with Clovis materials. Specifically focusing on the
Columbia Plateau, we apply a series of Bayesian chronological models to create concise estimates of the most likely beginning,
end, and span of the WST.We then further explore its chronology by modeling its temporal span under various parameters and
criteria so as to better identify places in the chronology that need further work and those that are robust regardless of data
iteration. Our analysis revealed four major findings: (1) WST conservatively dates between 13,000 and 11,000 cal BP, likely
extending to ∼13,500 cal BP; (2) the most problematic period for WST is its termination; (3) the WST is incredibly long-lived
compared to roughly contemporary Paleoindian traditions; and (4) the WST was seemingly unaffected by the onset of the
Younger Dryas
Journal of Island and Coastal Archaeology, 2017
Methodological advancements in geoarchaeology and spatial and chronological modeling are opening ... more Methodological advancements in geoarchaeology and spatial and chronological modeling are opening new avenues to interpreting large coastal shell-bearing sites. We document the developmental histories of two such sites around Prince Rupert Harbour, Canada, using systematic percussion coring, intensive radiocarbon dating, and 3D surface mapping with Total Station and LiDAR. We also re-analyze a third site (Boardwalk/GbTo-31) excavated and radiocarbon dated in the 1960s, 1970s, and early 2000s using archival field notes, site maps, and stratigraphic profiles georectified using LiDAR. We map the natural landform beneath the sites and document the degree to which Bryn Letham et al.
International Journal of Historical Archaeology, 2018
The fur trade era is difficult to radiocarbon date. We demonstrate Bayesian methods robustly reso... more The fur trade era is difficult to radiocarbon date. We demonstrate Bayesian methods robustly resolve some of the issues, applying them to radiocarbon date samples from two fur-trade era Native villages on the Lower Columbia River. Cathlapotle has a rich fur trade era documentary and artifact record; Meier has no documentary record and a sparse fur-trade era artifact record. We successfully tested the methods on Cathlapotle as a proof of concept and resolved empirical issues at both sites. The analysis suggests depopulation of both sites, probably resulting from epidemics , began in the mid to late eighteenth century but before direct contact.
We consider the provocative idea of whether urbanism as a condition or process is visible in Nort... more We consider the provocative idea of whether urbanism as a condition or process is visible in Northern tsimshian archaeology. We define the condition of urbanism through four traits, each of which we associate with measurable variables. We explore changes in these across the study area in 100-year time bins over 6000 years. We also consider urbanism as a process that includes five kinds of relations. We consider these through six chronological stanzas visible in our metric data. While there is evidence of changes towards urbanism, we argue that urbanism as a condition is not evident in our data. We propose that urbanism involves a suite of causes and trajec-tories with multiple potential outcomes, not all of which achieve the threshold of cities.
Hunter Gatherer Research, 2017
We consider the provocative idea of whether urbanism as a condition or process is visible in Nort... more We consider the provocative idea of whether urbanism as a condition or process is visible in Northern tsimshian archaeology. We define the condition of urbanism through four traits, each of which we associate with measurable variables. We explore changes in these across the study area in 100-year time bins over 6000 years. We also consider urbanism as a process that includes five kinds of relations. We consider these through six chronological stanzas visible in our metric data. While there is evidence of changes towards urbanism, we argue that urbanism as a condition is not evident in our data. We propose that urbanism involves a suite of causes and trajec-tories with multiple potential outcomes, not all of which achieve the threshold of cities.
Proceedings of the National Academy of Science USA, 2017
We extend an established simulation-based method to test for significant short-duration (1–2 cent... more We extend an established simulation-based method to test for significant short-duration (1–2 centuries) demographic events known from one documented historical and one oral historical context. Case study 1 extrapolates population data from the Western historical tradition using historically derived demographic data from the catastrophic European Black Death/bubonic plague (Yersinia pestis). We find a corresponding statistically significant drop in absolute population using an extended version of a previously published simulation method. Case study 2 uses this refined simulation method to test for a settlement gap identified in oral historical records of descendant Tsimshian First Nations communities from the Prince Rupert Harbour region of the Pacific Northwest region of British Columbia, Canada. Using a regional database of n = 523 radiocarbon dates, we find a significant drop in relative population using the extended simulation-based method consistent with Tsimshian oral records. We conclude that our technical refinement extends the utility of radiocarbon simulation methods and can provide a rigorous test of demographic predictions derived from a range of historical sources.
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Thesis Chapters by Thomas J Brown
The results of the demographic models suggest that while population levels were volatile, volatility declined through time and that there is no significant trend in either growth or decline of overall population levels throughout the region. This thesis also confirmed that significant changes to mobility, as evidenced by the emergence of semi-sedentary to sedentary living, begin to appear by ~7,000 cal BP. However, there appears to be little, if any correlation between the advent of more sedentary and logistic behavior and any of the variables tested here. Thus this author suggests, in agreement with Ames (1985; 2004) and Binford (2001) that the distribution of resources and labor organization needs within aquatic environments are sufficient without any other drivers for the development and intensification of logistic mobility. The principle analytic contribution of this research comes from the demographic modeling that relied on the construction of summed probability distributions. Though these methods have become commonplace in other settings (namely Europe), this thesis presents the first application of these methods within the time period and region covered. Moreover, this research is one of the only of its kind to address demographic histories within coastal landscapes that utilizes both marine and terrestrial 14C samples. In order to explore possible biases within the database, comparisons of marine and terrestrial SPDs were made between sub-sections of the region (i.e. Haida Gwaii, Southeast Alaska and the Dundas Islands). Though patterning between each of these areas was consistent, these comparative methods revealed an unexpected finding; a massive population crash throughout the region that began between ~9,000-8,800 cal BP and lasted till around 8,400 cal BP. Importantly, this crash was witnessed within all of the individual sub-areas and within SPDs made from both the marine and terrestrial 14C samples, though the reasons behind this collapse and verification of its existence require future research. However, finding this collapse at all further highlighted the need for use of correctly calibrated 14C dates, as the gap in 14C dates effectively disappears when using uncalibrated dates, which has been a longstanding tradition within Northwest archaeology.
Papers by Thomas J Brown
been an epicenter of hunter-gatherer research, but attention has
focused on the period after 5000 cal BP. Using data largely produced
within the past 12 years, we present the first synthesis and analysis
of this region’s 14C record between 11000 and 5000 cal BP. Our
analysis produced two primary findings (i) that the number of dated
sites does not increase or decrease significantly during this period
and (ii) there is an unexplained gap in dated sites across the entire
region between 9000 and 8300 cal BP. The existence of this gap
has critical implications regarding hypotheses of technological
change, migration, population continuity, and cultural evolution for
the region. However, available explanations for this gap are problematic.
Possible causes investigated include: demographic abandonment
of the region, distorting effects of the calibration curve, sealevel
change, taphonomy, and sampling error. All are found to
be inadequate.
regionally referred to as the Western Stemmed Tradition (WST). While various efforts have attempted to clarify the chronology
of this tradition, these have largely focused on data from the Great Basin and have been disproportionately preoccupied with
establishing the beginning of the tradition due to its temporal overlap with Clovis materials. Specifically focusing on the
Columbia Plateau, we apply a series of Bayesian chronological models to create concise estimates of the most likely beginning,
end, and span of the WST.We then further explore its chronology by modeling its temporal span under various parameters and
criteria so as to better identify places in the chronology that need further work and those that are robust regardless of data
iteration. Our analysis revealed four major findings: (1) WST conservatively dates between 13,000 and 11,000 cal BP, likely
extending to ∼13,500 cal BP; (2) the most problematic period for WST is its termination; (3) the WST is incredibly long-lived
compared to roughly contemporary Paleoindian traditions; and (4) the WST was seemingly unaffected by the onset of the
Younger Dryas
The results of the demographic models suggest that while population levels were volatile, volatility declined through time and that there is no significant trend in either growth or decline of overall population levels throughout the region. This thesis also confirmed that significant changes to mobility, as evidenced by the emergence of semi-sedentary to sedentary living, begin to appear by ~7,000 cal BP. However, there appears to be little, if any correlation between the advent of more sedentary and logistic behavior and any of the variables tested here. Thus this author suggests, in agreement with Ames (1985; 2004) and Binford (2001) that the distribution of resources and labor organization needs within aquatic environments are sufficient without any other drivers for the development and intensification of logistic mobility. The principle analytic contribution of this research comes from the demographic modeling that relied on the construction of summed probability distributions. Though these methods have become commonplace in other settings (namely Europe), this thesis presents the first application of these methods within the time period and region covered. Moreover, this research is one of the only of its kind to address demographic histories within coastal landscapes that utilizes both marine and terrestrial 14C samples. In order to explore possible biases within the database, comparisons of marine and terrestrial SPDs were made between sub-sections of the region (i.e. Haida Gwaii, Southeast Alaska and the Dundas Islands). Though patterning between each of these areas was consistent, these comparative methods revealed an unexpected finding; a massive population crash throughout the region that began between ~9,000-8,800 cal BP and lasted till around 8,400 cal BP. Importantly, this crash was witnessed within all of the individual sub-areas and within SPDs made from both the marine and terrestrial 14C samples, though the reasons behind this collapse and verification of its existence require future research. However, finding this collapse at all further highlighted the need for use of correctly calibrated 14C dates, as the gap in 14C dates effectively disappears when using uncalibrated dates, which has been a longstanding tradition within Northwest archaeology.
been an epicenter of hunter-gatherer research, but attention has
focused on the period after 5000 cal BP. Using data largely produced
within the past 12 years, we present the first synthesis and analysis
of this region’s 14C record between 11000 and 5000 cal BP. Our
analysis produced two primary findings (i) that the number of dated
sites does not increase or decrease significantly during this period
and (ii) there is an unexplained gap in dated sites across the entire
region between 9000 and 8300 cal BP. The existence of this gap
has critical implications regarding hypotheses of technological
change, migration, population continuity, and cultural evolution for
the region. However, available explanations for this gap are problematic.
Possible causes investigated include: demographic abandonment
of the region, distorting effects of the calibration curve, sealevel
change, taphonomy, and sampling error. All are found to
be inadequate.
regionally referred to as the Western Stemmed Tradition (WST). While various efforts have attempted to clarify the chronology
of this tradition, these have largely focused on data from the Great Basin and have been disproportionately preoccupied with
establishing the beginning of the tradition due to its temporal overlap with Clovis materials. Specifically focusing on the
Columbia Plateau, we apply a series of Bayesian chronological models to create concise estimates of the most likely beginning,
end, and span of the WST.We then further explore its chronology by modeling its temporal span under various parameters and
criteria so as to better identify places in the chronology that need further work and those that are robust regardless of data
iteration. Our analysis revealed four major findings: (1) WST conservatively dates between 13,000 and 11,000 cal BP, likely
extending to ∼13,500 cal BP; (2) the most problematic period for WST is its termination; (3) the WST is incredibly long-lived
compared to roughly contemporary Paleoindian traditions; and (4) the WST was seemingly unaffected by the onset of the
Younger Dryas