The Dirt on Soil Analysis

Contributed by Emma Cook

My latest work for the Peabody Inventory and Rehousing Project has led me to Tehuacán, where I have been cataloguing glass jars that contain soil samples. These jars are a part of the Tehuacán Archaeological-Botanical Project by Richard “Scotty” MacNeish during the early 1960s. The samples were collected for testing and analysis purposes from the project area. When archaeologists excavate a site, they dig through soil layers formed by the activities of past people. What archaeologists recover from these layers provides clues about what happened at that site from features or artifacts. However, the actual soil is another very important clue for archaeologists, as it can help date sites and tell a lot about the environment of the site during the time the soil layers were formed.

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Jars of Soil Samples from the Tehuacán Archaeological-Botanical Project, 1960s

Giving an accurate description of soils help archaeologists better understand what happened in the past at a site. The color and texture of soil can reveal the age of an archaeological site, as well as how the site was used. For example, a circular stain in the soil may reveal a post-hole deposit, indicating that there was once a wooden post that had decayed, leaving a soil discoloration in the ground. Depending on the site, these post-holes could represent a structure or palisade. In addition, studying soil fertility can help archaeologists understand ancient agricultural systems.

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MacNeish (left) and a field assistant analyzing stratigraphy at the Gladstone site on Kluane Lake in the Yukon.

Archaeologists use the Munsell Color Chart to help them describe the colors of the soil layers in a standardized way. This system was developed by Albert H. Munsell at what is now MassArt in 1905. Archaeologists compare the soil color in their excavation units to the color chips of the Munsell Chart – similar to the color squares found in hardware stores for paint. Where a color may be brown to one person, it may be gray to another – so it is important that archaeologists use this chart so they can standardize their descriptions.

Munsell Color Chart
Munsell Color Chart

To describe soil textures, archaeologists and geomorphologists use a soil triangle to help them determine what type of soil they are examining in the field. There are three types of soil components: sand, silt, and clay. Most soils have a combination of these three components and each of these components vary in sizes – sand particles being the largest and clay particles being the smallest. Similar to how the Munsell Color Chart describes soil color the same way, the soil triangle helps archaeologists describe soil texture consistently.

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Soil Triangle – Courtesy of the United States Department of Agriculture

Another way archaeologists analyze their site is through soil stratigraphy. This is the different types of strata, or layers of soil that archaeologists examine to map out the archaeological site over time. Stratigraphy can be used to determine which soil was associated with human occupation and which layers are sterile, meaning the soil is not associated with human occupation and does not contain any archaeological material. Layers that include artifacts and features represent a place where people lived and worked, as archaeologists can see the objects left behind by human activity. Sterile layers such as subsoil, flood sediment, and bedrock are not as distinct, but provide information on a site’s activity or inactivity.

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Archaeologists mapping out the stratigraphy at Purron Cave, TC 272, in the Tehuacán Valley.

The jars of soil samples were most likely examined after excavation and retained for further analysis. Presently, these soil samples have been rehoused and cataloguing for each of these jars is complete. To learn more about Richard “Scotty” MacNeish and the Tehuacán Archaeological-Botanical Project, visit the Peabody’s online archival collections. The MacNeish archives are available for research, separated into two collections – the Richard S. MacNeish Papers and the Richard S. MacNeish Records.

 

Further Readings

Birkeland, Peter W. 1974. Pedology, Weathering, and Geomorphological Research, New York: Oxford University Press.

Limbrey, Susan. 1975. Soil Science and Archaeology. London and New York: Academic Press.

Solecki, R. 1951. Notes on Soil Analysis and Archaeology. American Antiquity, 16(3), 254-256.

Uninvited Guests

Contributed by John Bergman-McCool

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Meet Mold and Salt

In early February we wrapped up inventorying and rehousing collections that originated in Missouri. The work was followed by two weeks of cleaning, and as a result we’ve completed one of the regions held in the collection. So you may be wondering what we were cleaning. During the inventory, we encountered bone and antler objects covered with salt crystals and patchy dormant mold. The objects were cleaned before they were stored inside their new boxes to remove salt and minimize the risk of mold spreading to unaffected objects.

Where did the mold and salt come from and why are they a problem?

Mold spores are found everywhere in the environment. When the humidity is high, those spores germinate resulting in mold. Because it is a living organism, mold is classified in the museum world as an agent of biological deterioration. It eats organic matter, in this case the dust resting on the outer surface of bone or the bone itself, and secretes waste that can stain or damage the surface that it is growing on. Mold can appear to be dormant, but when the conditions are right mold will generate spores that are easily borne on the wind, allowing it to spread quickly.

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Agents of deterioration

Salts on the other hand are considered chemical agents of deterioration. They are brought into museum collections on the objects themselves.  Dissolved salts present in groundwater can be absorbed by porous objects, such as bone, while they are buried underground. After the water evaporates the salts are left behind. Excessively humid conditions can dissolve soluble salts, allowing them to move through porous objects. When they arrive at the surface they form crystals. If the crystals form below the surface they can exert enough force to cause damaging cracks and spalling.

Mold and salt thrive in damp environments where the Relative Humidity (RH) is above 65%. The institute’s storage area is located in the basement, which does not have a controlled climate, so mold and salt are an unfortunate reality. Currently, the RH in the basement is somewhere below 15% (15% is as low as our monitoring equipment can read). RH levels this low shouldn’t support active mold and salt growth, so what we found is inactive, but it is hard to say when and for how long the growth of mold and salt was last active.

At the Peabody we are committed to maintaining the longevity of this very important research collection and salt and mold pose a risk to its scientific viability. Damage to the surface of artifacts caused by mold and salt can negatively impact the research value of the collection.

How do we prevent mold and salt?

While we don’t have an HVAC system maintaining the environment in basement storage, we have adopted a few practices that will mitigate and prevent future growth of mold and salt. First, we use dehumidifiers during times of high humidity that typically arise during the summer. Second, we are moving the artifacts currently stored in open drawers and rehousing them in closed archival boxes. The enclosed space of a box helps create a buffer that protects the contents from rapid shifts in RH that lead to mold and salt growth. The boxes will also keep future mold growth from spreading; something that was not possible with open-drawer storage.

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Vacuum defeats Mold and Salt

In addition to the rehousing, we have implemented a cleaning program. When mold and salt are identified we isolate the effected object to keep spores from spreading. We clean the affected artifacts with a dry brush and vacuum. After we clean we use sachets of silica gel to absorb excess moisture, thereby providing another buffer against cycles of RH increases and decreases. In six months we’ll check on the status of the bone to see if the mold and salt are staying away.

More Than a Number: Cataloguing the Peabody Collection

Contributed by Emma Cook

My name is Emma Cook, I am the Administrative Assistant at the Robert S. Peabody Institute of Archaeology. I have a background in archaeology, history, and museum studies with undergraduate and graduate degrees from the University of Georgia and Tufts University. Aside from my administration duties, I work with the Peabody’s collections. Recently I’ve been involved in the Inventory and Rehousing Project and I am working with collections on the first floor South Alcove, located in one of our gallery/classroom spaces.

The Robert S. Peabody Institute of Archaeology collection comprises nearly 600,000 artifacts, photographs, and archives. Some of these materials are displayed and used for teaching, while many reside in our collection storage. What is unique about much of our collection space is its original storage. The bays and drawers in which many of these artifacts inhabit are almost as old as the Peabody itself, the bays being first built in the early 1920s. However, below the surface of these pine wood bays and drawers are a collection of uncatalogued objects that have hardly come to light (literally), with some still stored in the tin foil and paper bags they were placed in upon archaeological excavation many years ago.

The antiquated charm of these wooden bays is not enough to meet the need of accessible storage for our collections and the goal is to replace them with new custom-built shelves. In preparation of this storage renovation, objects need to be identified, catalogued, and rehoused. This work is completed through our Inventory and Rehousing Project.

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First Floor, South Alcove – where my cataloguing work began

I began my work simply inventorying the objects in each drawer of each bay in the alcove. Some of these objects were already identified, numbered, and recorded in Past Perfect – a museum software that is the standard for cataloguing museum collections. Through this software, the Peabody collection is documented and made accessible online. My job was to make sure these objects were accounted for and in the right place, as well as properly rehoused and organized within the drawers. Sounds pretty easy right? Well, eventually things changed as I came across several drawers and bays containing objects with old numbers or no numbers at all. This is where my cataloguing efforts began.

Cataloguing is the process of recording details about an object into a collection catalog or database that documents the information of each object as well as its location in storage. Through this process each object receives a unique number. This number is physically attached to the object and appears in records related to the object in Past Perfect. In museums and archives, objects or materials in a collection are normally catalogued in what is called a collection catalog. In the past, this was traditionally done using a card index, but in the present-day it is normally implemented using a computerized database – for the Peabody this is Past Perfect. Some of the objects I came across with “old numbers” were either connected to the Peabody’s past card index cataloguing system or the Peabody’s original numbering system (i.e. 1,2,3,…. 78,049).

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Lithic objects with affixed labels and old numbers

Each object was given a new number associated with the Peabody’s present catalog numbering sequence (i.e. 2019.1.123). This numbering sequence is a three-part number, making it both simple and expandable. The first part of the sequence is the year in which the object was accessioned or catalogued (i.e. 2019). The second part of the sequence is given to objects in chronological order based on when they were first accessioned (i.e. 2019.1). The third part of the sequence gives a single object a number in chronological order (i.e. 2019.1.1). Objects that had an affixed label had the new number written on the label. Objects without labels had their numbers painted on with ink. A solution called B72 is applied to the object before the ink in order to protect the original surface of each object. This solution is not harmful to the object and can be easily removed if a mistake is made or the object needs a different number.

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Lithic objects with new numbers painted on their surface using ink and the B72 solution

The cataloguing process is not an easy one, nor is inventorying and rehousing a collection. The process may be slow and tedious, but it does have its rewards. By using a great deal of care, time, and effort, rehoused and identified objects can be used for teaching and research. Not only can collection staff have full access to the collection, they can provide a safe and accessible place for these materials in storage. The cataloguing process may seem like a trivial task, but it just goes to show – it’s more than a number.

For more information and reading on the Inventory and Rehousing Project, see the following blogs below:

Transcribing the Collection – January 2019

A New Face in the Basement – January 2019

Ceramic Inventory Complete – December 2018

Collections Reboxing Project Update – April 2018

A Day in the Life of Boxing Boxes – November 2017

Shelving to the Rescue – September 2016

Boxes and Boxes and Boxes – August 2016

Summer Work Duty Students Begin Rehousing Inventory – August 2016

A New Face in the Basement

Contributed by John Bergman-McCool

Hi there! My name is John and I am the new Inventory Specialist at the Robert S. Peabody Institute. As Inventory Specialist my primary task is to work on the ongoing inventory and rehousing project. The project’s goals are to fully understand the collections that are held at the Institute and move them from their old wooden drawers into archival boxes. Armed with the more precise knowledge of what is in the Peabody, the institute can ensure their continued care and share them with students and the public for years to come.

This position is a dream job for me. It brings together my interest in archaeology, museums and collections care, and who doesn’t love spending time underground!

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Yep, this is me in a bell pit during an excavation in Arizona!

Before moving to Massachusetts in 2013, I worked for almost a decade as an archaeologist in the Pacific Northwest and Arizona. After relocating to New England I enrolled in the MFA program at Tufts and the School of the Museum of Fine Arts. During my time as a graduate student I found that I kept coming back to archaeology and the history of museum collections as a subject for my artwork.

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Artwork from my thesis project

While I was in graduate school I also pursued a certificate in Museum Studies. I gravitated towards collections care and since graduating I’ve worked in collections at the Fitchburg Art Museum and Historic New England. ­

In a round-about way I’ve come back to archaeology, though it’s been following me for the past 5 years. During my time here I’ve been inventorying objects from Missouri. There have been some surprising finds, which has been great. You never know what you’re going to find here at the Peabody.

Party’s not over – volunteering at the Peabody

Contributed by Quinn Rosefsky ’59

No one invited us to the party but we’ve stayed for over nine years. And the desserts keep getting better. Not that what we do would come under the category of party. What should be obvious to readers of this blog is that I am talking about what it is like to volunteer at the Peabody Institute. First of all, who can volunteer? Being a graduate of Phillips Academy helps in passing the rigorous entrance examination but there are exceptions, such as my wife, Susan, whose qualifications, while many, started with marriage. This automatically reduces the interview process (but does not eliminate the background check.) And what do volunteers do?

Some of you might get the wrong impression that all we do is what the staff shy away from. Far from it. There have been plenty of occasions where it was all we could do to pry staff apart from a project to allow us to either dig into the unknown (such as categorizing about one hundred yards of unclassified photos) or finish it off (such as one hundred yards of labels.)

Of course, I am exaggerating. (No point in frightening you.) I have handled (and often read) documents from the nineteenth and twentieth centuries; paleolithic artifacts from 10,000 B.C.E; ledgers with tens of thousands of entries. I can picture specific bifaces, sherds and feathers.

What my wife, Susan, and I have been doing has varied considerably over the years as staff have come and gone, priorities have shifted, and time frames have expanded. I like to think that volunteering has allowed the Peabody to think in terms of decades, not centuries. This might come as a surprise until you consider that the Peabody is home to somewhere in the vicinity of 600,000 artifacts.

For quite a number of the past nine years, Susan and Leah (another spectacular volunteer) have been inspecting, vacuuming and protecting textiles from Guatemala. Although the end of the project has been in their sights for the past year, Einstein’s theory of special relativity keeps getting in the way (time slowing, distances shortening…easy stuff.) Eager to try my own hand at a multitude of projects, my time has been slowed as well. Despite Einstein’s slowing of time as we operate at the speed of light, sadly, all of us working as an extended family inside the Peabody’s walls have grown somewhat older (but not by much and not at the same rate.)

Most recently, I had the task of filling out labels to put on a few of the 1,500 drawers containing a variety of artifacts. It was a matter of necessity, not just my dexterity and eye coordination. When I completed that task, it was my honor to look for the “absence” of items. It all started with the discovery that an item had been “mislabeled.” That’s akin to looking through a haystack and saying you didn’t find the needle. And winning means you did not find the needle.

Sometimes I write blogs. I’ll stop here because my limit is 500 words. (Only staff can do more!)

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Quinn after volunteering for 9 years

Ayacucho animals migrate to the Peabody

Contributed by Marla Taylor

Artifact collections are not meant to stagnate – museum collections are meant to be researched, examined, and shared.  In a perfect world, all loans are returned promptly and paper-work is meticulous. But, let’s be real, in an institution with 100+ years of history, this is not often the case. Fortunately, some past researchers remember you when it is time to relocate collections.

Circa 1972, Scotty MacNeish sent faunal material from the Ayacucho Valley of Peru to Dr. Kent Flannery of the University of Michigan for analysis. Dr. Flannery is a prominent zooarchaeologist who specializes in investigating the origins of agriculture in Mesoamerica and the Near East.  Many know Flannery from his 1976 book The Early Mesoamerican Village and his 1982 article The Golden Marshalltown: A Parable for the Archeology of the 1980s. Dr. Flannery completed the Ayacucho faunal analysis and sent data and a written chapter (for Volume I of the Prehistory of the Ayacucho Basin) back to MacNeish. But the artifacts were not returned until July, 2018.

Dr. Flannery, and the Museum of Anthropological Archaeology at the University of Michigan, shipped us 493 bags and 11 small boxes of faunal material.  A loan from 45 years ago, of course, did not have much paperwork, though we did locate the original Peruvian export permits and customs documents. But, all bags and boxes are now inventoried and part of the Peabody collection. The material is from Jaywamachay Cave, Ruyru Rumi Cave, and Chumpas Cave in the Ayacucho Valley.

Why does this matter? These collections can now be made available to a new generation of researchers and are reunited with other materials from MacNeish’s Ayacucho work.

If you want to learn more about the Ayacucho Valley and MacNeish’s work, check out the First Annual Report and Second Annual Report on the Ayacucho Archaeological Botanic Project. Some of the published volumes are available for free via the HathiTrust Digital Library.

Different but the Same

Contributed by Alex Hagler ’16

Before I officially became a staff member here at the Peabody, I was a volunteer and work duty student. I started volunteering at the Peabody about nine years ago, and when I came to Phillips Academy as a student I immediately signed on to do work duty. As a volunteer and work duty student, I worked to catalogue and inventory returned artifact loans, set out class activities, digitize records, and photograph artifacts. Since going to college out of state about two years ago, I have not been back at the Peabody, other than for brief visits. Reflecting on my time working here, it is fascinating, and somewhat nostalgic, to look back at what the Peabody was like when I started all those years ago and how it has changed so much since then!

When I started volunteering here, the Peabody was still officially a museum and still had standing exhibit space on the first floor. Some of those exhibit cases displayed artifacts, others dioramas or archaeology-related activities done by some Phillips Academy classes. Down in the collections, we used white cotton gloves to handle artifacts, rather than the purple nitrile gloves we use now. The reboxing project had not begun, so much of the work I did was cataloguing and inventorying in preparation for when that project might get funding. While I was doing work-duty, I sat in on some meetings about how to make the Peabody more accessible to Phillips Academy students, both in terms of the collections and the building space as a whole. Since then, the Peabody has initiated student study hours, during which the building is open to students as a study space, and renovated the first floor to make it more class-friendly!

It has been just over two years since I graduated from Phillips Academy, and I am so happy to be back working here! I study archaeology in college, and so working here, albeit temporarily, is an opportunity not only to continue learning how to preserve archaeological collections, but also to put into practice what I have learned at school, namely how to make archaeology more accessible for everyone.

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Inventorying the never-ending drawers

 

Collections Summer Summary

Contributed by Marla Taylor

Another summer is nearly gone and the school year is about to begin.  Sometimes, I get asked “what do you do when the students aren’t here?” Well… everything!

In the past couple of months, the collections department has inventoried and rehoused over 100 artifact drawers! This included an ambitious project (and maybe a little bit crazy) to reorganize the ceramics from the Scotty MacNeish collection. MacNeish stored the ceramics by typology – useful for analysis, but really unhelpful for collections management.  Objects with the same catalog number were spread out over 8 to 12 different drawers and were not easy to locate for researcher or class use. It took over a week to empty, consolidate, and inventory 55 drawers. But now everything is easy to access!

I have also been teaching Annie Greco, inventory specialist, and Rachel Manning, our new collections assistant, the basics of pest management and mitigation. We inspected artifacts for insect activity and damage and then learned how to properly clean objects that have been affected. Fortunately, nothing serious was found and it was a valuable exercise for all of us.

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Annie and Rachel examine an artifact for pest activity.

Also, outside research does not follow the school year patterns. I have been working with several professors to facilitate access to Peabody collections for a variety of projects.

Summer at the Peabody is a different pace than the school year, but not any slower!

Exciting Changes!

I have been working as the Inventory Specialist at the Peabody for the past year. It has been an incredibly rewarding experience and I have learned a great deal, not only about the collections at the Peabody, but about collections and artifacts from other institutions throughout the United States as well.

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It is with great pleasure that I will be taking on the position of Collections Assistant at the Robert S. Peabody Institute of Archaeology! With this new position comes a variety of new responsibilities that I am ready to undertake. While I will still be inventorying drawers as time allows, I will focus more on drawers that have been adopted through our Adopt A Drawer program. Through this program, donors can “adopt” a drawer housed at the Peabody! They receive updates on the progress of the inventory and rehousing of the artifacts in the drawer and pictures of what is inside. Upon completion, a write-up with information pertaining to the age, origin and various other details about the artifacts within the drawer is sent to the donor. Interested in participating? Contact Peabody director Ryan Wheeler (rwheeler@andover.edu).

Another major part of the position will be monitoring the environment in the various collections spaces. Maintaining proper relative humidity and temperature is imperative to keeping a healthy collection. Fluctuations in these variables can be detrimental to the collection and cause damage to and have other undesirable effects on the artifacts. In addition to environmental monitoring, I will also be in control of the Integrated Pest Management program. Keeping on top of pest activity in any institution is the best way to avoid an infestation. This is especially important in museums where irreplaceable artifacts can be damaged by insect activity.

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Here I am, monitoring the environment.

A third big change will be working more closely with our volunteers and work duty students who spend time at the Peabody helping us with a few of the many tasks that need to be accomplished. Once a week groups of students from Phillips Academy assigned work duty at the Peabody will take time doing anything from inventorying drawers to digitally inputting information from catalog cards and ledgers. We also have a group of volunteers who join us once a week to inventory drawers, perform inspections of our ethnographic materials, or do other tasks as they present themselves. If this sounds like something interesting to you or anyone you know, feel free to contact us about volunteering at the Peabody!

I am very excited to be able to contribute to the Peabody in new ways!

More boxes of boxes

Today we unloaded another truck full of custom boxes from Hollinger Metal Edge.  This batch of 1,500 boxes is our final purchase with the Box Us In! Abbot grant that was generously funded by the Abbot Academy Fund in 2015, continuing Abbot’s tradition of boldness, innovation, and caring.

The ongoing project to obtain physical and intellectual control over our collections continues!