Martijn Blaauw
Biographic Data
| ID | 952114 |
|---|---|
| NAME | Martijn Blaauw |
| GIVEN NAMES | Martijn |
| FAMILY NAME | Blaauw |
| SIGNATURE | BLAAUW M |
| AFFILIATIONS | Queen's University Belfast |
| ORCID | 0000-0002-5680-1515 |
| VERIFIED | Yes |
| TOTAL WORKS | 34 |
| TOTAL CITATIONS | 130 |
| AUTHOR COUNT | 33 |
| EDITOR COUNT | 1 |
| FIRST PUBLICATION YEAR | 2002 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 7 |
An open-source toolkit for radiocarbon dating and calibration
The analysis and interpretation of radiocarbon dates can involve many steps, such as switching between units or time-scales, assessing the impacts of contamination, applying marine or other offsets, inspecting calibration curves, calibrating dates, extracting probabilities from calibrated distributions, and analysing and plotting multiple dates. Here, we present rice , a new open-source R package which, together with other packages such as rbacon…
Mike Baillie – Slices of Time
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Modelling chronologically ordered radiocarbon dates in R
Studies with multiple radiocarbon dates often contain useful information on the relative locations of the dated levels. Such information can be used to obtain robust, integrated site chronologies, with at times more precise ages than those of the individual dates, where outliers can be identified and downweighted, and where the ages of any undated levels can also be estimated. Examples include trees with radiocarbon dates separated by exactly kno…
Development of the Intcal Database
The IntCal family of radiocarbon ( 14 C) calibration curves is based on research spanning more than three decades. The IntCal group have collated the 14 C and calendar age data (mostly derived from primary publications with other types of data and meta-data) and, since 2010, made them available for other sorts of analysis through an open-access database. This has ensured transparency in terms of the data used in the construction of the ratified c…
Reconciling 22,000 years of landscape openness in a renowned wilderness
Here, we explore the profound impact of the Tasmanian Aboriginal (Palawa) people on Tasmanian landscapes by examining a 22,000-year record of landscape change from Lake Selina in western Tasmania, Australia. We analysed a sediment core for palaeoecological proxies, namely, pollen (vegetation), charcoal (fire), and geochemical data (landscape weathering). This study reveals that the contemporary landscape is a product of Palawa people's intentiona…
The IntCal20 Approach to Radiocarbon Calibration Curve Construction
To create a reliable radiocarbon calibration curve, one needs not only high-quality data but also a robust statistical methodology. The unique aspects of much of the calibration data provide considerable modeling challenges and require a made-to-measure approach to curve construction that accurately represents and adapts to these individualities, bringing the data together into a single curve. For IntCal20, the statistical methodology has undergo…
The Importance of Open Access to Chronological Information
The development of chronologies relies on integrating information from a number of different sources. In addition to direct dating evidence, such as radiocarbon dates, researchers will have contextual information which might be an environmental sequence or the context in an archaeological site. This information can be combined through Bayesian or other types of age-model. Once a chronology has been developed, this information can be used to estim…
A Multi-Proxy Reconstruction of Environmental Change in the Vicinity of the North Bay Outlet of Pro-Glacial Lake Algonquin
We present a multi-proxy study of environmental conditions during and after the recessional phases of pro-glacial Lake Algonquin in the vicinity of the North Bay outlet, Great Lakes Basin. Data presented comes from a new sedimentary profile obtained from the Balsam Creek kettle lake c. 34 km north-east of the city of North Bay. This site lies close to the north-east margin of the maximum extent of the post-Algonquin lake sequence, which drained t…
The Epistemic Dimensions of Ignorance
Ignorance is a neglected issue in philosophy. This is surprising for, contrary to what one might expect, it is not clear what ignorance is. Some philosophers say or assume that it is a lack of knowledge, whereas others claim or presuppose that it is an absence of true belief. What is one ignorant of when one is ignorant? What kinds of ignorance are there? This neglect is also remarkable because ignorance plays a crucial role in all sorts of contr…
Perspectives on Ignorance from Moral and Social Philosophy
Lake Kumphawapi revisited – The complex climatic and environmental record of a tropical wetland in NE Thailand
Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture avai…
A geochronologic framework for the Ziegler Reservoir fossil site, Snowmass Village, Colorado
The Ziegler Reservoir fossil site near Snowmass Village, Colorado (USA), provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the Last Interglacial Period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10 Be and 26 Al ages on a boulder on the cres…
Summary of the Snowmastodon Project Special Volume A high-elevation, multi-proxy biotic and environmental record of MIS 6–4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA
In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland…
Air pollutant contamination and acidification of surface waters in the North York Moors, UK
Despite the extensive geographical range of palaeolimnological studies designed to assess the extent of surface water acidification in the United Kingdom during the 1980s, little attention was paid to the status of surface waters in the North York Moors (NYM). In this paper, we present sediment core data from a moorland pool in the NYM that provide a record of air pollution contamination and surface water acidification. The 41-cm-long core was di…
Towards mapping the late Quaternary vegetation change of Europe
The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we …
A millennial record of environmental change in peat deposits from the Misten bog (East Belgium)
The pitfalls of tuned proxy archives
Examining the uncertainties in a ‘tuned and stacked’ peatland water table reconstruction
Flexible paleoclimate age-depth models using an autoregressive gamma process
Radiocarbon dating is routinely used in paleoecology to build chronologies of lake and peat sediments, aiming at inferring a model that would relate the sediment depth with its age. We present a new approach for chronology building (called "Bacon") that has received enthusiastic attention by paleoecologists. Our methodology is based on controlling core accumulation rates using a gamma autoregressive semiparametric model with an arbitrary number o…
Vegetation responses to rapid climatic changes during the last deglaciation 13,500–8,000 years ago on southwest Andøya, arctic Norway
Methods and code for ‘classical’ age-modelling of radiocarbon sequences
Random walk simulations of fossil proxy data
A wealth of palaeoecological studies (e.g. pollen, diatoms, chironomids and macrofossils from deposits such as lakes or bogs) have revealed major as well as more subtle ecosystem changes over decadal to multimillennial timescales. Such ecosystem changes are usually assumed to have been forced by specific environmental changes. Here, we test if the observed changes in palaeoecological records may be reproduced by random simulations, and we find th…
Linking past cultural developments to palaeoenvironmental changes in Estonia
A multi-proxy palaeoenvironmental investigation of the findspot of an Iron Age bog body from Oldcroghan, Co. Offaly, Ireland
Subject Sensitive Invariantism
Subject sensitive invariantism is the view that whether a subject knows depends on what is at stake for that subject: the truth-value of a knowledge-attribution is sensitive to the subject's practical interests. I argue that subject sensitive invariantism cannot accept a very plausible principle for memory to transmit knowledge. I argue, furthermore, that semantic contextualism and contrastivism can accept this plausible principle for memory to t…
The IntCal20 Approach to Radiocarbon Calibration Curve Construction
To create a reliable radiocarbon calibration curve, one needs not only high-quality data but also a robust statistical methodology. The unique aspects of much of the calibration data provide considerable modeling challenges and require a made-to-measure approach to curve construction that accurately represents and adapts to these individualities, bringing the data together into a single curve. For IntCal20, the statistical methodology has undergo…
Towards mapping the late Quaternary vegetation change of Europe
The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we …
Evidence from northwest European bogs shows ‘Little Ice Age’ climatic changes driven by variations in solar activity
Fluctuations in Holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity. Analyses of both 10Be and 14 C nuclides con” rm that production-rate changes during the Holocene were largely modulated by solar activity. Analyses of peat samples from two intact European ombrotrophic bogs show that climatic deteriorations during the ‘Little Ice Age’ are associated with transitions to increasing atmospheric …
Testing the timing of radiocarbon-dated events between proxy archives
For interpreting past changes on a regional or global scale, the timings of proxy-inferred events are usually aligned with data from other locations. However, too often chronological uncertainties are ignored in proxy diagrams and multisite comparisons, making it possible for researchers to fall into the trap of sucking separate events into one illusionary event (or vice versa). Here we largely solve this ‘suck in and smear syndrome’ for radiocar…
The Importance of Open Access to Chronological Information
The development of chronologies relies on integrating information from a number of different sources. In addition to direct dating evidence, such as radiocarbon dates, researchers will have contextual information which might be an environmental sequence or the context in an archaeological site. This information can be combined through Bayesian or other types of age-model. Once a chronology has been developed, this information can be used to estim…
A Bayesian Framework for Age Modeling of Radiocarbon-Dated Peat Deposits
Recently, Bayesian statistical software has been developed for age-depth modeling (“wiggle-match dating”) of sequences of densely spaced radiocarbon dates from peat cores. The method is described in non-statistical terms, and is compared with an alternative method of chronological ordering of 14 C dates. Case studies include the dating of the start of agriculture in the northeastern part of the Netherlands, and of a possible Hekla-3 tephra layer …
Solar forcing of climatic change during the mid-Holocene
Two cores of mid-Holocene raised-bog deposits from the Netherlands were 14 C wiggle-match dated at high precision. Changes in local moisture conditions were inferred from the changing species composition of consecutive series of macrofossil samples. Several wet-shifts were inferred, and these were often coeval with major rises in the Δ 14 C archive (probably caused by major declines in solar activity). The use of Δ 14 C as a proxy for changes in …
Linking past cultural developments to palaeoenvironmental changes in Estonia
Changes in solar activity and Holocene climatic shifts derived from 14C wiggle-match dated peat deposits
Closely spaced sequences of accelerator mass spectrometer (AMS) 14 C dates of peat deposits display century-scale wiggles which can be fitted to the radiocarbon calibration curve. By wiggle-matching such sequences, high-precision calendar age chronologies can be generated which show that changes in mire surface wetness during the Bronze Age/Iron Age transition (c. 850 cal. BC) and the ‘Little Ice Age’ (Wolf, Spörer, Maunder and Dalton Minima) occ…
A multi-proxy palaeoenvironmental investigation of the findspot of an Iron Age bog body from Oldcroghan, Co. Offaly, Ireland
Reconciling 22,000 years of landscape openness in a renowned wilderness
Here, we explore the profound impact of the Tasmanian Aboriginal (Palawa) people on Tasmanian landscapes by examining a 22,000-year record of landscape change from Lake Selina in western Tasmania, Australia. We analysed a sediment core for palaeoecological proxies, namely, pollen (vegetation), charcoal (fire), and geochemical data (landscape weathering). This study reveals that the contemporary landscape is a product of Palawa people's intentiona…
Lake Kumphawapi revisited – The complex climatic and environmental record of a tropical wetland in NE Thailand
Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture avai…
Vegetation responses to rapid climatic changes during the last deglaciation 13,500–8,000 years ago on southwest Andøya, arctic Norway
Contesting Pyrrhonian Contrastivism
I air three kinds of problem to which Sinnott-Armstrong's epistemological contrastivism seems to be exposed: (a) the theory gives an unplausible account of justification attributions; (b) the Pyrrhonism which results from its inability to identify relevant contrast classes bars us from epistemic responsibility; (c) contextualism does just as well as Pyrrhonism, despite Sinnott-Armstrong's arguments to the contrary. © 2008 The Author
Development of the Intcal Database
The IntCal family of radiocarbon ( 14 C) calibration curves is based on research spanning more than three decades. The IntCal group have collated the 14 C and calendar age data (mostly derived from primary publications with other types of data and meta-data) and, since 2010, made them available for other sorts of analysis through an open-access database. This has ensured transparency in terms of the data used in the construction of the ratified c…
A Multi-Proxy Reconstruction of Environmental Change in the Vicinity of the North Bay Outlet of Pro-Glacial Lake Algonquin
We present a multi-proxy study of environmental conditions during and after the recessional phases of pro-glacial Lake Algonquin in the vicinity of the North Bay outlet, Great Lakes Basin. Data presented comes from a new sedimentary profile obtained from the Balsam Creek kettle lake c. 34 km north-east of the city of North Bay. This site lies close to the north-east margin of the maximum extent of the post-Algonquin lake sequence, which drained t…
Random walk simulations of fossil proxy data
A wealth of palaeoecological studies (e.g. pollen, diatoms, chironomids and macrofossils from deposits such as lakes or bogs) have revealed major as well as more subtle ecosystem changes over decadal to multimillennial timescales. Such ecosystem changes are usually assumed to have been forced by specific environmental changes. Here, we test if the observed changes in palaeoecological records may be reproduced by random simulations, and we find th…
Subject Sensitive Invariantism
Subject sensitive invariantism is the view that whether a subject knows depends on what is at stake for that subject: the truth-value of a knowledge-attribution is sensitive to the subject's practical interests. I argue that subject sensitive invariantism cannot accept a very plausible principle for memory to transmit knowledge. I argue, furthermore, that semantic contextualism and contrastivism can accept this plausible principle for memory to t…
Evidence from northwest European bogs shows ‘Little Ice Age’ climatic changes driven by variations in solar activity
Fluctuations in Holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity. Analyses of both 10Be and 14 C nuclides con” rm that production-rate changes during the Holocene were largely modulated by solar activity. Analyses of peat samples from two intact European ombrotrophic bogs show that climatic deteriorations during the ‘Little Ice Age’ are associated with transitions to increasing atmospheric …
Late Holocene climatic changes in Tierra del Fuego based on multiproxy analyses of peat deposits.
A ca. 1400-yr record from a raised bog in Isla Grande, Tierra del Fuego, Argentina, registers climate fluctuations, including a Medieval Warm Period, although evidence for the ‘Little Ice Age’ is less clear. Changes in temperature and/or precipitation were inferred from plant macrofossils, pollen, fungal spores, testate amebae, and peat humification. The chronology was established using a 14 C wiggle-matching technique that provides improved age …
Changes in solar activity and Holocene climatic shifts derived from 14C wiggle-match dated peat deposits
Closely spaced sequences of accelerator mass spectrometer (AMS) 14 C dates of peat deposits display century-scale wiggles which can be fitted to the radiocarbon calibration curve. By wiggle-matching such sequences, high-precision calendar age chronologies can be generated which show that changes in mire surface wetness during the Bronze Age/Iron Age transition (c. 850 cal. BC) and the ‘Little Ice Age’ (Wolf, Spörer, Maunder and Dalton Minima) occ…
Solar forcing of climatic change during the mid-Holocene
Two cores of mid-Holocene raised-bog deposits from the Netherlands were 14 C wiggle-match dated at high precision. Changes in local moisture conditions were inferred from the changing species composition of consecutive series of macrofossil samples. Several wet-shifts were inferred, and these were often coeval with major rises in the Δ 14 C archive (probably caused by major declines in solar activity). The use of Δ 14 C as a proxy for changes in …
Epistemology A-Z
Divorcing theism from infallibilism
Robert Oakes has argued that theism defeats the ‘doctrine of public-world fallibilism’. That is, Oakes has argued that theism supports infallibilism about public-world beliefs such as ‘There is an olive on the floor’, or ‘I have two hands’. Given the enormous discussion of radical scepticism in the recent epistemological literature, this argument is well worth investigating. In this short note, however, I argue that the argument Oakes presents is…
Testing the timing of radiocarbon-dated events between proxy archives
For interpreting past changes on a regional or global scale, the timings of proxy-inferred events are usually aligned with data from other locations. However, too often chronological uncertainties are ignored in proxy diagrams and multisite comparisons, making it possible for researchers to fall into the trap of sucking separate events into one illusionary event (or vice versa). Here we largely solve this ‘suck in and smear syndrome’ for radiocar…
A Bayesian Framework for Age Modeling of Radiocarbon-Dated Peat Deposits
Recently, Bayesian statistical software has been developed for age-depth modeling (“wiggle-match dating”) of sequences of densely spaced radiocarbon dates from peat cores. The method is described in non-statistical terms, and is compared with an alternative method of chronological ordering of 14 C dates. Case studies include the dating of the start of agriculture in the northeastern part of the Netherlands, and of a possible Hekla-3 tephra layer …
A multi-proxy palaeoenvironmental investigation of the findspot of an Iron Age bog body from Oldcroghan, Co. Offaly, Ireland
Subject Sensitive Invariantism
Subject sensitive invariantism is the view that whether a subject knows depends on what is at stake for that subject: the truth-value of a knowledge-attribution is sensitive to the subject's practical interests. I argue that subject sensitive invariantism cannot accept a very plausible principle for memory to transmit knowledge. I argue, furthermore, that semantic contextualism and contrastivism can accept this plausible principle for memory to t…
Contesting Pyrrhonian Contrastivism
I air three kinds of problem to which Sinnott-Armstrong's epistemological contrastivism seems to be exposed: (a) the theory gives an unplausible account of justification attributions; (b) the Pyrrhonism which results from its inability to identify relevant contrast classes bars us from epistemic responsibility; (c) contextualism does just as well as Pyrrhonism, despite Sinnott-Armstrong's arguments to the contrary. © 2008 The Author
Linking past cultural developments to palaeoenvironmental changes in Estonia
Methods and code for ‘classical’ age-modelling of radiocarbon sequences
Random walk simulations of fossil proxy data
A wealth of palaeoecological studies (e.g. pollen, diatoms, chironomids and macrofossils from deposits such as lakes or bogs) have revealed major as well as more subtle ecosystem changes over decadal to multimillennial timescales. Such ecosystem changes are usually assumed to have been forced by specific environmental changes. Here, we test if the observed changes in palaeoecological records may be reproduced by random simulations, and we find th…
Flexible paleoclimate age-depth models using an autoregressive gamma process
Radiocarbon dating is routinely used in paleoecology to build chronologies of lake and peat sediments, aiming at inferring a model that would relate the sediment depth with its age. We present a new approach for chronology building (called "Bacon") that has received enthusiastic attention by paleoecologists. Our methodology is based on controlling core accumulation rates using a gamma autoregressive semiparametric model with an arbitrary number o…
Vegetation responses to rapid climatic changes during the last deglaciation 13,500–8,000 years ago on southwest Andøya, arctic Norway
A millennial record of environmental change in peat deposits from the Misten bog (East Belgium)
The pitfalls of tuned proxy archives
Examining the uncertainties in a ‘tuned and stacked’ peatland water table reconstruction
Towards mapping the late Quaternary vegetation change of Europe
The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we …
A geochronologic framework for the Ziegler Reservoir fossil site, Snowmass Village, Colorado
The Ziegler Reservoir fossil site near Snowmass Village, Colorado (USA), provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the Last Interglacial Period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10 Be and 26 Al ages on a boulder on the cres…
Summary of the Snowmastodon Project Special Volume A high-elevation, multi-proxy biotic and environmental record of MIS 6–4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA
In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland…
Air pollutant contamination and acidification of surface waters in the North York Moors, UK
Despite the extensive geographical range of palaeolimnological studies designed to assess the extent of surface water acidification in the United Kingdom during the 1980s, little attention was paid to the status of surface waters in the North York Moors (NYM). In this paper, we present sediment core data from a moorland pool in the NYM that provide a record of air pollution contamination and surface water acidification. The 41-cm-long core was di…
Lake Kumphawapi revisited – The complex climatic and environmental record of a tropical wetland in NE Thailand
Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture avai…
The Epistemic Dimensions of Ignorance
Ignorance is a neglected issue in philosophy. This is surprising for, contrary to what one might expect, it is not clear what ignorance is. Some philosophers say or assume that it is a lack of knowledge, whereas others claim or presuppose that it is an absence of true belief. What is one ignorant of when one is ignorant? What kinds of ignorance are there? This neglect is also remarkable because ignorance plays a crucial role in all sorts of contr…
Geology and Paleoclimatology Research (23 works) · Geography (19 works) · Geology (18 works) · Archaeology (15 works) · Physical geography (14 works) · Radiocarbon dating (14 works) · Archaeology and ancient environmental studies (12 works) · Holocene (12 works) · Paleontology (11 works) · Peat (11 works)