Freek Braadbaart
Utrecht University, Earth Sciences, Faculty Member
- Universiteit Leiden, Archaeology, Faculty MemberUniversiteit Leiden, Institute of Biology, Faculty Memberadd
In the archaeological record, ash and charred organic material are the only indications of the type of fuel used by ancient societies to feed their fires. This potential source of information may help further understanding of past human... more
In the archaeological record, ash and charred organic material are the only indications of the type of fuel used by ancient societies to feed their fires. This
potential source of information may help further understanding of past human behaviour in relation to fuel selection, applied type of fire and function of
fires lit in hearths. This study examined ash from reference samples and ash and char samples recovered from an Iron Age peatland site in Vlaardingen,
the Netherlands. Local availability and abundance made it possible for the occupants of the site to choose from different fuel resources. Peat and cattle
dung were readily available, while wood was less abundant. Reference samples from various locations were collected to investigate the properties of
ash. Different types of wood, peat and cattle dung were accordingly ashed and analysed. In total, two techniques were used, that is, chemical analyses
(x-ray fluorescence (XRF)) for the determination of the elemental composition and microscopic studies on field images of these ashes, mounted on glass
slides, to investigate phytoliths quantitatively (Si and Ca types), siliceous aggregates and spherulites. The properties of the archaeological samples were
compared with these results. The archaeological char samples were used for identification and analysed using reflective microscopy to study structure
and temperature by reflectance (%Ro). It provided the necessary information to determine the type of fuel used by the Iron Age farmers and obtain more
information on the function of the present fire structures. The results are strong indications that Iron Age farmers used all available fuels, that is, peat,
cattle dung and wood, to feed their fires. The integrated application of phytolith, geochemical and char analyses has a high potential for the identification
of the fuel selected by ancient societies.
potential source of information may help further understanding of past human behaviour in relation to fuel selection, applied type of fire and function of
fires lit in hearths. This study examined ash from reference samples and ash and char samples recovered from an Iron Age peatland site in Vlaardingen,
the Netherlands. Local availability and abundance made it possible for the occupants of the site to choose from different fuel resources. Peat and cattle
dung were readily available, while wood was less abundant. Reference samples from various locations were collected to investigate the properties of
ash. Different types of wood, peat and cattle dung were accordingly ashed and analysed. In total, two techniques were used, that is, chemical analyses
(x-ray fluorescence (XRF)) for the determination of the elemental composition and microscopic studies on field images of these ashes, mounted on glass
slides, to investigate phytoliths quantitatively (Si and Ca types), siliceous aggregates and spherulites. The properties of the archaeological samples were
compared with these results. The archaeological char samples were used for identification and analysed using reflective microscopy to study structure
and temperature by reflectance (%Ro). It provided the necessary information to determine the type of fuel used by the Iron Age farmers and obtain more
information on the function of the present fire structures. The results are strong indications that Iron Age farmers used all available fuels, that is, peat,
cattle dung and wood, to feed their fires. The integrated application of phytolith, geochemical and char analyses has a high potential for the identification
of the fuel selected by ancient societies.
and FREDERICK BRAADBAART " Summary.-This article examines the problem of urban groundwater mining in West Java, Indonesia. Groundwater tables in urban West Java have been sinking rapidly for two decades. Overpumping has driven up pumping... more
and FREDERICK BRAADBAART " Summary.-This article examines the problem of urban groundwater mining in West Java, Indonesia. Groundwater tables in urban West Java have been sinking rapidly for two decades. Overpumping has driven up pumping costs while intruding salt or polluted water threatens groundwater quality. Industrial pumpers are mainly responsible for the increase in groundwater exploitation. Government efforts to regulate groundwater exploitation have so far lacked the street-level impact needed to stop the pumping race. Shifting the focus of monitoring and regulation from factory boreholes to factory waste-water outlets is discussed as a possible solution to the problem of limited administrative capacity. 0 1997 Elsevier Science Ltd. All rights reserved
In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the... more
In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the fire proxy heated bone. Two types of heating can be distinguished: combustion (or burning, with oxygen) and charring (without oxygen), for both of which the formation of char is the first step. We performed a series of controlled laboratory-based heating experiments, in reducing conditions (i.e. charring), covering a broad temperature range (20–900 °C), and applied a variety of different analytical techniques. Results indicate that charred bone shows a distinctly different thermal alteration trajectory than combusted bone, which has implications for the suitability of the different analytical techniques when identifying and determining past heating conditions (charring vs. combustion; temperature) of heated bone from archaeological contexts. Combined, the reference data and techniques presented in this study can be used as a robust toolkit for the characterisation of archaeological charred bone from various ages and contexts.
In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the... more
In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the fire proxy heated bone. Two types of heating can be distinguished: combustion (or burning, with oxygen) and charring (without oxygen), for both of which the formation of char is the first step. We performed a series of controlled laboratory-based heating experiments, in reducing conditions (i.e. charring), covering a broad temperature range (20–900 °C), and applied a variety of different analytical techniques. Results indicate that charred bone shows a distinctly different thermal alteration trajectory than combusted bone, which has implications for the suitability of the different analytical techniques when identifying and determining past heating conditions (charring vs. combustion; temperature) of heated bone from archaeological contexts. Combined, the reference data and techniques presented in this study can be used as a robust toolkit for the characterisation of archaeological charred bone from various ages and contexts.
and FREDERICK BRAADBAART " Summary.-This article examines the problem of urban groundwater mining in West Java, Indonesia. Groundwater tables in urban West Java have been sinking rapidly for two decades. Overpumping has driven up pumping... more
and FREDERICK BRAADBAART " Summary.-This article examines the problem of urban groundwater mining in West Java, Indonesia. Groundwater tables in urban West Java have been sinking rapidly for two decades. Overpumping has driven up pumping costs while intruding salt or polluted water threatens groundwater quality. Industrial pumpers are mainly responsible for the increase in groundwater exploitation. Government efforts to regulate groundwater exploitation have so far lacked the street-level impact needed to stop the pumping race. Shifting the focus of monitoring and regulation from factory boreholes to factory waste-water outlets is discussed as a possible solution to the problem of limited administrative capacity. 0 1997 Elsevier Science Ltd. All rights reserved
Research Interests:
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After extracting oil from olives a residue is left usually referred to as the olive oil processing residue (OPR). This study explores the way in which ancient societies may have used OPR as fuel for fires to generate heat and the various... more
After extracting oil from olives a residue is left usually referred to as the olive oil processing residue (OPR). This study explores the way in which ancient societies may have used OPR as fuel for fires to generate heat and the various issues that are related to the residues of this fuel. After drying, the high heating value and structure of OPR makes it an excellent and efficient fuel. Upgrading OPR further, through thermal conversion or charring, provides an even more efficient fuel (COPR), with a hotter and smoke free flame, a higher heating value and which is lighter in mass and thus easier to transport. After a fire is extinguished two types of remains of the fuel are left i.e. char and ash. Analyses on both remains, recovered from archaeological deposits, could be used as a source of information on fuel utilization. Laboratory experiments on charred modern OPR and stones show that by measuring their reflectance and analyzing their structure under reflected light microscopy, OPR and COPR can be distinguished in the charred material recovered from three archaeological sites in Greece and Syria. Based on these investigations it is suggested that on the three sites COPR was used as fuel. Ash, sampled together with the char, provides the possibility of investigating if other types of fuel were used, apart from OPR or COPR. On the investigated sites no ash was collected, but the analysis of the modern OPR showed that the properties of its ash could be used to distinguish it from other types of fuel. Ash from modern OPR and olive stones showed the presence of phytoliths. The often discussed issue related to the sharp-ness and smoothness of the edges of charred fragmented olive stones was investigated. The results showed that this is not a reliable criterion for recognizing olive oil production. It is recommended that in addition to the identification of the botanical material more properties of the remains of fuels should be analysed. To prevent destroying and losing char and ash as a result of excavation activities such as flotation and sieving, special measures have to be taken. The results show that analysing char and ash may provide valuable information on the (pyro)technology practised in ancient societies.