UCLA/Getty Conservation Program

A graduate conservation training program focusing on the conservation of archaeological and ethnographic materials


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“Animal, Vegetable, Mineral?” – Identifying mystery fibers in the field

When conservators are working on archaeological excavations, their work often encompasses many different aspects of field conservation.  This can include materials identification and characterization, lifting fragile artifacts and aiding in archaeological research.  No matter what facet of the project they are involved in, the work can be challenging without the comforts of a well-stocked lab and requires lots of problem solving and improvisation.  Last summer while working on the Ancient Methone Archaeological Project, we were faced with the challenge of trying to identify an unusual looking fibrous material which required us to MacGyver a transmitted light microscope to aid in the examination and identification of the mystery fibers.

During the 2014 season, a team of geomorphologists working on the project were taking core samples in an area thought to be an ancient harbor.  In one of the cores, they pulled out a clump of fibers they thought might be cordage (fig. 1).  They brought the samples to the conservation lab to see if we could identify the fibers and determine if it was cordage or the remnants of woven fibers. Some samples were set aside for radiocarbon dating and the remainder of the sample, which was still bound in sediment, was examined.

Figure 1. Clump of fibers found in soil core by Geomorph team. Photo: Ancient Methone Archaeological Project

Figure 1. Clump of fibers found in a core sample taken by the Geomorphology team. Photo: Ancient Methone Archaeological Project

The initial macroscopic examination revealed that the fibers appeared translucent (fig. 2).  They seemed to be grouped into bundles and some of these bundles initially appeared to cross each other, giving the impression of a woven structure.

Fgiure 2. Detail of the fibers encased in the sediment.  The fibers are translucent and are grouped in bundles.  Photo: Ancient Methone Archaeological Project

Fgiure 2. Detail of the fibers encased in the sediment. The fibers are translucent and are grouped in bundles. Photo: Ancient Methone Archaeological Project

The fibrous material was encased in a gray, silty sediment, which appeared to include quartz, foliated phyllosilicates/sheet silicates (like mica, vermiculite, etc.) (fig. 3), as well as small shells, both fragmented and whole (fig. 4). The sample was initially wet, and was allowed to slowly dry out in the lab. The sediment was gently pushed away using a pin-vise under binocular magnification, to better define the structures and reveal diagnostic features of the material for its identification (fig. 5).  Photographs of the fibers were taken using the DinoLite USB microscope (7013MZT Series). During this examination and initial cleaning, the fibers were found to be very brittle.  Though they appeared to be in bundles, they were not actually bound to each other and could be easily separated.

Figure 3.  During cleaning, plate-like inclusions were found in the soil and between the fiber bundles.  These inclusions resembled sheet silicates like mica. Photo: Ancient Methone Archaeological Project

Figure 3. During cleaning, plate-like inclusions were found in the soil and between the fiber bundles. These inclusions resembled sheet silicates like mica. Photo: Ancient Methone Archaeological Project

Figure 4.  Small shells or shell fragments were also found in the deposit. Photo: Ancient Methone Archaeological Project

Figure 4. Small shells or shell fragments were also found in the deposit. Photo: Ancient Methone Archaeological Project

Figure 5.  After some initial cleaning to remove soil, more of the fiber bundles and associated materials are visible. Photo: Ancient Methone Archaeological Project

Figure 5. After some initial cleaning to remove soil, more of the fiber bundles and associated materials are visible. Photo: Ancient Methone Archaeological Project

Though examination with a stereomicroscope helped to reveal more about the fibers and the structure of the bundles, we were not able to clearly identify what the fibers were.  We felt that examination using transmitted light microscopy would be the most helpful since it could highlight any morphological features in the fiber that could aid in identification.  So we set out to make one armed with our DinoLite microscope and a flashlight. The set up turned out to be quite simple. We just needed to be able to shine a light through the fibers from below and examine the fibers at a high magnification using the DinoLite (fig. 6). We took a fiber bundle from the sediment and placed it on a multi-bulb LED flashlight (fig. 7).  This flashlight was flat and rectangular and the ideal shape for our light source since the fiber samples could be directly placed on the top surface of the flashlight.  The fact that the flashlight was flat also meant it was easy to position the light source under the microscope where needed (fig. 8).

Figure 6.  We created a transmittled light microscope using the DinoLite USB microscope and an LED flashlight which acted as the transmitted light source. Photo: Ancient Methone Archaeological Project

Figure 6. We created a transmittled light microscope using the DinoLite USB microscope and an LED flashlight which acted as the transmitted light source. Photo: Ancient Methone Archaeological Project

Figure 7. We placed samples of the fibers directly onto the flashlight during examination. Photo: Ancient Methone Archaeological Project

Figure 7. We placed samples of the fibers directly onto the flashlight during examination. Photo: Ancient Methone Archaeological Project

Figure 8.  Using our transmitted light  microscope to examine the fibers.  Macguyver would be proud. Photo: Ancient Methone Archaeological Project

Figure 8. Using our transmitted light microscope to examine the fibers. Macgyver would be proud! Photo: Ancient Methone Archaeological Project

Looking at the fibers in transmitted light, we observed a central void within some of the fibers.  Since we were considering the possibility of the fibers being organic in nature, we thought these central voids could be the medulla or lumen of an organic fiber (fig. 9). However, no other morphological features were present that helped us determine at this point what the fibers were.

Figure 9. Looking at the fibers under transmitted light, we could see they had a central void, which initially made us think this was the lumen of a plant fiber or medulla of an animal fiber. Photo: Ancient Methone Archaeological Project

Figure 9. Looking at the fibers under transmitted light, we could see they had a central void, which initially made us think this was the lumen of a plant fiber or medulla of an animal fiber. Photo: Ancient Methone Archaeological Project

We were also able to take a look at the cross-section of the fibers with the addition of a polarizing lens on the DinoLite (fig 10). Some fibers appeared hexagonal in section (fig. 11).  Some of the ends of the fibers ended in a point or were triangular in shape.

Figure 9.  With the addition of a polarizing lens on the DinoLite we were able to see the cross-sections of some of the fibers.  Some appeared hexagonal or triangular in section. Photo: Ancient Methone Archaeological Project

Figure 9. With the addition of a polarizing lens on the DinoLite we were able to see the cross-sections of some of the fibers. Some appeared hexagonal or triangular in section. Photo: Ancient Methone Archaeological Project

Figure 11.  Details of the fibers showing their shape in section.  Photo: Ancient Methone Archaeological Project

Figure 11. Details of the fibers showing their shape in section. Photo: Ancient Methone Archaeological Project

Further cleaning revealed a tiered growth structure that resembled the growth of minerals more than plant or animal fiber bundles (fig. 12).  The inclusion of sheet silicates in relation to the fibers, either located between bundles or within them further suggested these fibers were mineral.  In searching the literature we came across images of asbestos minerals which looked similar to our mystery fibers.  Several types of asbestos minerals are fibrous in appearance (fig. 13), and can occur near phyllosilicate deposits.  Armed with this information we concluded that the fibers were definitely mineral in nature and could possibly be asbestos.

Figure 12.  Fiber bundle after cleaning. Photo: Ancient Methone Archaeological Project

Figure 12. Fiber bundle after cleaning. Photo: Ancient Methone Archaeological Project

Figure 13. An image of crocidolite, a fibrous form of the mineral riebeckite, and one of the 6 recognized forms of asebstos minerals.  © Raimond Spekking / , via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/b3/Krokydolith_-_Mineralogisches_Museum_Bonn_%287385%29.jpg

Figure 13. An image of crocidolite, a fibrous form of the mineral riebeckite, and one of the 6 recognized forms of asebstos minerals. © Raimond Spekking / , via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/b3/Krokydolith_-_Mineralogisches_Museum_Bonn_%287385%29.jpg

Luckily we were able to bring a sample of the fibers back with us and conduct some analysis in the UCLA/Getty Conservation labs. And we were quite surprised by the results!  It turns out we were correct in deducing the fibers were mineral in nature, but we were incorrect about which mineral. XRF and XRD analysis did not find any asbestos minerals in the sample, but instead the fibers were identified as calcite (fig. 14).  Though we had never seen calcite that was fibrous in appearance, it is one of the mineral’s crystal forms. An example is shown in fig. 15 where you can see the SEM image of “lublinite”, a needle-type of calcite whose form is thought to be associated with the activity of microorganisms.

Figure 14. XRD analysis results showing the fibers were composed of calcite.

Figure 14. XRD analysis results showing the fibers were composed of calcite.

Figure 15. SEM image of lublinite, the fibrous form of calcite.  Image taken from: http://www.speleonics.com.au/jills/bymineral/lublinite.html

Figure 15. SEM image of lublinite, the fibrous form of calcite. Image taken from: http://www.speleonics.com.au/jills/bymineral/lublinite.html

Even though we were not able to identify the fibers as calcite in the field, the use of a stereomicroscope and our makeshift transmitted light microscope certainly helped distinguish their mineral nature and rule out plant or animal origins.  And now that we’ve figured out how to make a transmitted light microscope and tested it out, we’re ready for any future material ID questions that would require one.

MacGyver looks on and smiles at our ingenuity.  Photo: http://macgyver.wikia.com/wiki/List_of_problems_solved_by_MacGyver

MacGyver looks on and smiles at our ingenuity. Photo: http://macgyver.wikia.com/wiki/List_of_problems_solved_by_MacGyver

Written by the 2014 Ancient Methone Archaeological Project Conservation Team: Heather White (UCLA/Getty Program Grad Student, Class of ’16), Vanessa Muros (Conservation Specialist/Lecturer, UCLA/Getty Program) and Anna Weiss (Campus Art/Artifact Collections Coordinator, Conservator, Univ. of Chicago)


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UCLA/Getty Program takes on the SAA’s (and Honolulu)

This spring students, staff and faculty of the UCLA/Getty Conservation Program will be attending the Society for American Archaeology’s Annual Meeting (April 3-7, in Honolulu, HI) and representing the field of archaeological conservation. Faculty member and chair, Dr. Ioanna Kakoulli, and I have co-organized a symposium titled Archaeometric Methods, Archaeological Materials & Ancient Technologies which takes place on Sat. April 6th and is sponsored by the Society for Archaeological Sciences.

The session brings together professionals in the field of archaeology and conservation to present their research on the use of instrumental analysis for the characterization of ancient and historic materials. The aim is to create a discussion of the advantages and limitations of different techniques based both on hardware design and application methodology and the pitfalls in the acquisition and interpretation of results. The papers will touch on the methods of acquiring the data and how the data is treated in light of the complexities posed by the heterogeneous nature of archaeological materials and the alterations that they undergo during burial. There will be a focus on how condition/preservation issues, the heterogeneity of the artifacts and the difficultly of analyzing artifacts that cannot be sampled affect the techniques that can be used, the choice of analytical methodology and the interpretation of results. By addressing these limitations, and especially by having conservators speak on the impact of condition and deterioration on the overall composition and stability of archaeological materials, a new perspective can be added to the discussion of instrumental analysis that would be beneficial to any researcher working on ancient materials.

In addition to the research the presenters will introduce, the session will increase the presence of conservators, conservation scientists and conservation graduate students at this archaeological conference. The hope is it that it will introduce those not familiar with our field to conservation-related research, increasing the awareness of the archaeological community to the work conducted by conservators and their contribution to larger archaeological goals and research questions. This collaboration with and outreach to the archaeological community has been a focus of the UCLA/Getty Program and our hope is that this session will be an extension of that work and help bridge the gap that still exists between these two professions.

Not only are we happy about getting to spend some time in Honolulu, but we are excited to have two of our students presenting their research at the session. We have a few papers that will be given by emerging archaeological conservators giving them an opportunity to present their research at this early stage in their career. They’ll also have the opportunity to connect with archaeologists and other professionals which will help form collaborations in the future. As a result of this session, I hope these emerging conservators will wish to continue this kind of outreach during their conservation careers and work to further integrate conservation into the practice of archaeology.

If you are attending the SAA’s, make sure to come to our session to hear the exciting talks listed below (after the photo). Abstracts for the conference can be accessed here. Hope to see you in Honolulu!

beautiful beach in Hawaii (Not Honolulu or Oahu, but on the Big Island. Just wanted to set the mood)

A beautiful beach in Hawaii. It’s not Honolulu or Oahu, but the Big Island. It’s just in here to add context and because I’m sure Honolulu will be as beautiful.

Vanessa Muros
Conservation Specialist, UCLA/Getty Conservation Program

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Archaeometric Methods, Archaeological Materials & Ancient Technologies

Empire Without A Voice: Phoenician Iron Metallurgy and Imperial Strategy at Carthage
Brett Kaufman, PhD candidate, Cotsen Institute of Archaeology, UCLA

Analyzing deteriorated glass using pXRF: A preliminary study of vitreous beads from the Late Bronze Age/Early Iron Age tumulus of Lofkënd in Albania
Vanessa Muros, Conservation Specialist, UCLA/Getty Conservation Program

Several Roads Lead to Chichén Itzá: Tracing the Fabrication Histories of Metals Deposited in the Cenote Sagrado
Bryan Cockrell, PhD candidate, Anthropology, UC Berkeley
José Luis Ruvalcaba Sil, Research Scientist, Instituto de Física, UNAM
Edith Ortiz Díaz, Researcher in Archaeology, Instituto de Investigaciones Antropológicas, UNAM

Improving the Diagnostic Capabilities of GC-C-IRMS Analyses of Organic Residues in Archaeological Pottery
Michael W. Gregg, and Greg F. Slater
School of Geography and Earth Sciences, McMaster University

Comparison between 3D Geometric Morphometric Analysis over Traditional Linear Methods in Lithic Assemblages; Tor Faraj, Jordan, a Middle Paleolithic Site as a Case Study
Colleen A Bell, Miriam Belmaker and Donald Henry, Dept. of Anthropology, The University of
Tulsa

Characterization of 5th C. B.C. Athenian Pottery Black Gloss Slips
Marc Walton and Karen Trentelman, Getty Conservation Institute
Jeffrey Maish and David Saunders, J. Paul Getty Museum
Brendan Foran3, Neil Ives3, and Miles Brodie, The Aerospace Corporation
Apurva Mehta, Stanford Synchrotron Radiation Laboratory

Lipid Analysis and Plant Residue Identification: New Perspectives
Cynthianne Debono Spiteri , Dept. of Archaeology, BioArCh, University of York & Max Planck
Institute for Evolutionary Anthropology
Amanda Henry, Max Planck Institute for Evolutionary Anthropology
Oliver E. Craig, Dept. of Archaeology, BioArCh, University of York

Integrated Archaeometric Analysis of the Context and Contents of an Ulúa-style Marble Vase from the Palmarejo Valley, Northwest Honduras
E. Christian Wells, Ph.D., Department of Anthropology, University of South Florida

The Jaina-style Figurine Project: Portable Technologies, Advantages and Limitations
Christian Fischer, Dept. of Materials Science and Engineering and UCLA/Getty Conservation
Program
Carinne Tzadik, MA student, UCLA/Getty Conservation Program
Ioanna Kakoulli, Dept. of Materials Science and Engineering and Chair,UCLA/Getty Conservation
Program
Sandra L. Lopez Varela, Dept. of Anthropology, Universidad Autónoma del Estado de Morelos
Christian De Brer, Conservator, Fowler Museum at UCLA
Kim Richter, Research Specialist, Getty Research Institute

Sandstone raw materials from Eastern France: Evaluation of Non-Invasive Portable Technologies as Potential Tools for Characterization and Sourcing
Brittany Dolph, MA Student, UCLA/Getty Conservation Program
Christian Fischer, Dept. of Materials Science and Engineering and UCLA/Getty Conservation Program

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Analyzing deteriorated glass using pXRF: A preliminary study of vitreous beads from the Late Bronze Age/Early Iron Age tumulus of Lofkënd in Albania
Vanessa Muros, Conservation Specialist, UCLA/Getty Conservation Program

The availability of portable analytical instrumentation, such as portable xray fluorescence spectroscopy (pXRF), has allowed for more archaeometric research to be conducted on archaeological materials in the field, where artifacts can be analyzed in situ. The application of this technique to the study of ancient materials has been advantageous in that many more artifacts can be analyzed non-destructively, without the need for sampling. Issues are often encountered, however, in the characterization of these objects due to their heterogeneity because of the materials used, method of manufacture or the alteration materials undergo during burial.

This paper will describe the characterization of a group of vitreous beads excavated from the Late Bronze Age/Early Iron Age tumulus (14th-9th c. BC) of Lofkënd in Albania. The beads, which exhibited varying degrees of deterioration and corrosion, were analyzed using pXRF in order to identify the raw materials used. The factors considered in the creation of the analytical methodology will be presented. The challenges encountered in the interpretation of the results, and the importance of understanding the deterioration processes of archaeological materials when studying ancient artifacts will be discussed.

The Jaina-style Figurine Project: Portable Technologies, Advantages and Limitations
Christian Fischer, Dept. of Materials Science and Engineering and UCLA/Getty Conservation
Program
Carinne Tzadik, MA student, UCLA/Getty Conservation Program
Ioanna Kakoulli, Dept. of Materials Science and Engineering and Chair,UCLA/Getty Conservation
Program
Sandra L. Lopez Varela, Dept. of Anthropology, Universidad Autónoma del Estado de Morelos
Christian De Brer, Conservator, Fowler Museum at UCLA
Kim Richter, Research Specialist, Getty Research Institute 

Of all sites in the Mexican state of Campeche on the Yucatán Peninsula’s Gulf coast, the islet of Jaina has been in the spotlight for many years, principally, due to the very fine clay figurines found in great numbers within burial sites. Compared to the archaeological/art historical analysis, the archaeometry of Jaina figurines has been less extensive. The Jaina style figurine project applies a multiscale and multianalytical approach based on noninvasive and non-destructive testing for the chemical fingerprinting of the figurines and to investigate the degree of variability in the chemistry and technology among the figurines relative to the analytical uncertainties. Here we present preliminary data obtained using non-invasive technology based on spectral imaging (SI), Xray fluorescence (XRF) spectroscopy and ultraviolet, visible, near infrared (UV/Vis/NIR) reflectance spectroscopy for the characterization of the clay body and blue paint decoration. The advantages and limitations of the non-invasive techniques employed will be discussed in the context of material heterogeneity and variability, geometry and stylistic features of the figurines.

Sandstone raw materials from Eastern France: Evaluation of Non-Invasive Portable Technologies as Potential Tools for Characterization and Sourcing
Brittany Dolph, MA Student, UCLA/Getty Conservation Program
Christian Fischer, Dept. of Materials Science and Engineering and UCLA/Getty Conservation Program

In the Alsace region of eastern France, sandstone is an important local resource which has been utilized by societies throughout time. Although earliest archaeological evidence of usage dates back to the Neolithic, it is mainly during the Gallo-Roman and Medieval periods that this sandstone was extensively quarried, and nowadays is still commercially exploited for building and conservation purposes. Primarily composed of quartz, feldspars,
and various types and amounts of micas and clay minerals, the sandstone types present variegated colors and belong to different levels of the Buntsandstein, a lithostratigraphic unit of lower Triassic age. This research explores the potential of X-ray fluorescence (XRF) and ultraviolet/visible/near infrared (UV/Vis/NIR) spectroscopy for the non-invasive characterization of different Buntsandstein sandstone lithotypes using portable instrumentation. The two complementary non-invasive techniques allow identification of both elemental and mineralogical compositions while providing a useful alternative for the analysis of archaeological artifacts and/or field investigations where sampling is not an option. Furthermore, they can be used to document current condition and possible alteration processes in order to identify decision-making criteria for conservation treatments. Preliminary results obtained on reference samples from modern quarries exploiting the Buntsandtein sandstone will be presented and discussed with particular focus on provenance and sourcing.