Primary Research through the History of Beverly
Location of a Site
Gridding an Archaeological Site
Excavating an Archaeological Site
Tools Commonly found at a Site
Firing Point Chart
Potassium Argon Dating
Archaeology is a branch of Anthropology. Anthropology is the study of man in it’s broadest sense. Archaeology is the study of man’s past. Archaeologists accomplish heir task mainly through excavation. Excavation is the process of finding sites that may contain artifacts. Artifacts are relics of the past. They are anything created or influenced by man. Once an Archaeologist believes he has found a site possibly containing artifacts, he will begin excavating the site. There are many steps and procedures that have to be followed in order to excavate a sight professionally.
Once an artifact is found it has to be identified, labeled, and cataloged. There is three main categories that the artifacts fall under; pottery, bones and stone artifacts. Each of those categories is broken down further. An archeologist then uses artifacts that have been found to make a reconstruction the way people lived during that time period.
Archaeologists use two types of dating, relative and absolute. Relative dating is used to get an idea of when events took place or when certain items were made to put a more exact data on the artifact. Absolute dating is done later in the lab once everything is excavated. Different forms of absolute dating are radiocarbon and potassium argon dating. Examples of relative dating are Dendrochronology and palynology.
Finding a location is the most important way to begin and archaeological dig. Many sites are fairly easy to find because there are monumental. The Pyramids of Giza in Egypt, Pompeii, or an old house are all obvious sites for excavation. There are also archaeological sites that are not so clearly visible. These sites are sometimes submerged in water, or covered in dense vegetation. Many sites are buried underground and are not discovered until after they are uncovered by events such as an environmental change like an earthquake or a strong storm that causes ground erode.
Visible sites may not be apparent to an amateur’s eye. An experienced trained eye if an archaeologist will spot small soil erosion or a certain pattern in vegetation growth that is different in comparison to the average field. What may look like rubble of an old building could be the foundation of an old building perfect for an archaeological dig.
After discovering a site, important steps must be followed in order to ensure that a site is kept in order. First, an archaeological survey must be done. This is an extensive walking tour of an area of land in search of any surface artifacts, of visible sign of human influence. The land terrain and location area are also closely observed. Archaeologists search for mounds of gray soil such as animal burrows; and some of these mounds can reveal artifacts. “The key to an effective archaeological dig lies in carefully designing the research before one sets out to use techniques that estimate the probable density of archaeological sites in the region”
A more intensive survey requires the archaeologists or researcher to interview local inhabitants (if there are any), landowners, and to review documents regarding the site. Many areas of land are known for historical occurrences, these are obvious sites for archaeological study. There are geographic areas that are known for being heavily influenced by humans, which make them primary subjects for excavation; Crimea is one of these areas. Crimea has an actual palimpsest of inhabitants placed on a peninsula in the Black Sea, Crimea has had a diverse culture living in a small area of 15,000 square miles. Crimmerians were the first to settle there, until they were overthrown by the Scythians, who were later known as the Taurians. Greek settlers interwove with the Taurians allowing trade to become easy and extensive. By A.D. Crimea had been influenced by Sarmatians, Germanic Goths, Huns, Khazars, Pechenegs, Polovtsians, Slavs, and Mongols. Crimea would be an example of a good site for excavation of subterranean artifacts.
Subsurface detection methods are also highly effective. Hot air balloons, x-rays, and sonic detectors can all be used to map subterranean features and hidden chambers, which may not be visible from the ground. Satellite sensory known as LANDSAT CAN also help in the search for hidden geographic features. From the ground, a seismograph can detect shockwaves in the earth. Artifacts buried beneath the ground will conduct shockwaves faster than the surrounding ash. A ground-penetrating radar can determine the stratigraphy of an area. Both of these methods are accurate, however they are very expensive.
Ground surface is not the only place archaeologists’ look to find artifacts. The ocean is littered with artifacts from shipwrecks and items that rest o the ocean floor. Subsurface detection methods are very useful in determining what lies beneath the oceans surface, eliminating the need for a diver while searching for artifacts. This technology is being used extensively torward the study of the Titanic, as along with many other shipwrecks. The surrounding waters of the Greek Isles are rich with artifacts from the ancient Greek and ROMAN Civilizations. Subsurface detection is carefully used while searching these isles.4
A Geographic Information System (GIS) is a computer-aided system, that collects, stores, and presents a retrieval analysis of all spatial data. Accurate mapping, surface collection, and subsurface investigation using electronic detection methods can give an archaeologist large amounts of information before they devote money and time into an archaeological dig. “Observation is the key to finding archaeological sites and to study the subtle relationships between prehistoric settlements and the landscape on which they flourished.”5 Brian M Fagan, Archaeology A Brief Introduction Seventh Edition (Upper Saddle River, New Jersey; Prentice
Gridding your archaeological site can be a complicated task. What may seem easy at first, can soon become difficult. There are certain steps to be taken in order to grid a site. The size, measurements, and terrain of the site are the information needed to make gridding a site less complicated. In order to begin the gridding of an archaeological site, you need to do quite a few things. You must start by choosing your datum point, serving as the basis from which the grid is mapped out. If you look at Figure 1, the red dot in the center is the datum point located on the map. All squares around that point are labeled according to the datum point. If you look closely, you can see how to properly label the names for each square, also known as an excavation.
The next part is setting up the actual grid. The best terrranean would be a flat, soil filled area. Measuring tape will be needed, wood or metal stakes, as well as string or wire. To grid the total area after making simple measurements will ensure that all the squares will end up almost equal in size. After this step has been completed, the grid must be drawn on paper, complete with pictures of the steps throughout the excavation process. When doing so, carefully label your datum point, each excavation, and a compass determining which way is north. This process will provide critical information while excavating.
There is a simple process for labeling the excavation. Locate the datum point on your grid. Hold the map out so that North is pointing toward the North. Now for each square North of the datum point and going Eastward, label boxes in that direction N?E?. To the southeast right label them S?E?. Replace each question mark according to the squares’ location. For example: If a box is to the south 3 and 4 to the east from the datum point you would label it S3-E4. If further help is needed Figure 1 will be of assistance.
The final part of the site is to keep it up to date. The map should be duplicated in case of any lost information. Any duplicates should be updated along with the original. The site map will help to keep track of squares, which excavations have been completed or started already, and which squares are fresh. Taking occasional pictures gives a better look at the grid. Some examples from an archaeological dig can be viewed at www.reedfarmstead.com
The most important part of an archaeological dig is excavation. Excavation is the archaeologist’s main method of attaining data to analyze. The process of excavation is not easy. There are certain steps as well as methods that need to be followed. Weather also plays a role in excavation as it can have a great effect on the dig itself. Excavation is where the majority of artifacts are found and an archaeologist needs to have the knowledge of how to deal with these artifacts. A large number of tools are also a major part of the excavation process. It is vital for an archaeologist to know these tools as well as their uses.
An archeologist needs to be extremely attentive when conducted a dig as a site can only be excavated once. If something is missed, one can never go back to find it. If that was attempted there would be no stratigraphy and all of the data would be off. It is imperative that archaeologists follow certain methods in order to excavate and record a site properly. The deeper a person digs, the farther back in time he/she goes. Each layer represents a certain period of time determined by what is found in each increment. It is important that each square is excavated in the same manner. However, squares can be excavated in different kinds of stratigraphic levels. This means that the archaeologist can either follow the natural layers of the soil or determine a set depth for each unit. For example, in a dig conducted at Beverly High School the team of excavators dug in ten centimeter increments.
The first site excavated is usually not found on the official digging site. It is found nearby and known as the control pit. This pit is dug in order to learn the nature of the soils and deposits in an undisturbed state. The control pit helps to determine the type of stratigraphy that one could encounter during a dig. After the control pit is dug and examined the next step before digging is to lie out a grid on the site using the squares of the grid as a guide while excavating. Each pit is excavated one at a time and all material found in the pit is segregated according to the increment it was found in. The gathered material found in specified increments during excavation are placed in bags and labeled.
Excavation is not just digging and finding artifacts. It is uncovering a culture and for that reason it must not be hurried and all methods and procedures must be followed carefully. During excavation it is important that the archaeologist is not only focusing on the ground which he/she digs but also why these certain artifacts are there. Making connections is also part of excavation. All the information about context is preserved through careful excavation and by fully documenting artifacts with measurements, maps, and photographs. These tools will help with uncovering the contextual data of an artifact.
Weather can have a huge effect on the excavation process. An ideal excavation site is a moderately sunny area with light evening showers in order to keep the site moist and workable. Hot climates are not favored, as the site would be difficult to dig, as the entire site would be dried up. However, wet weather is also not an ideal situation as large amounts of rainfall can damage the site and also makes it harder to dig. When wet weather is expected it is important that the exposed areas of the site are covered with a tarp in order to protect the pit.
While digging, most people expect to find things such as sherds of pottery, stone and other prehistoric artifacts. These are all important to the excavation process but other artifacts that one needs to be on the lookout for are other materials such as pollen, plant parts, human and animal bone, shell, and textiles. Pollen and seeds are extremely important because after being tested the results can help determine climatic or even economic changes.
There are many different tools used during the process of excavation. Excavation can be done by hand or with heavy machinery. The example used in this text however used only hand tools. A trowel is used most often in excavation. It is used to slowly scrape away the dirt of a site with the side of a trowel blade. The blade must be kept at a ninety degree angle at all times and should be used to take the dirt of a site away evenly. Also, the point of the trowel should never be used. By using a trowel artifacts tend to show up clearly if the trowel is used properly the surface is usually flat and smooth. Another important tool is a camera. Cameras are used in order to take pictures of both the site as well as the artifacts. Pictures are extremely important to the excavation processes. Many pictures should be taken throughout the entire dig. Measurements are also extremely important. Because of that a ruler and line level are two more tools needed during the excavation process. The excavator needs to make sure that he has not traveled outside of his increment during the dig and so must use both the line level and ruler to check his depth often. Another tool is a bucket. The bucket has two uses. One use is to carry soil from the screening area to the site and the other is to hold water. The water is then used to put the trowel in. All seeds and pollen on the trowel will float. A dustpan is a tool found most often on a site. It is used for removing excavated soil with the help of the trowel. Brushes are also used in order to clean soil away from artifacts.
After the soil is removed it is sifted through mesh screens in order to recover the extremely small artifacts. Another important tool is a magnet. A magnet can be run above artifacts that are dirty in order to discover if they are magnetic. Tinfoil is yet another imperative tool in the excavation process. When an archaeologist finds anything with carbon on it (burnt firewood) he/she should not touch it. Instead they should wrap it in tinfoil and send it off for a carbon-14 dating test. Some sites will also use bathroom tissue as a tool. This is sometimes used to wrap bones in which will retain the moisture of the bone until it arrives at the lab. The tissue will also prevent disintegration.
It has been mentioned many times that an archeologist must follow certain steps during excavation. A few things that an excavator should never do is stand on the edge of a square that is being excavated. This could cause the square to cave in giving the archaeologist “scrambled eggs” a site with no stratigraphy. A person should also never touch carbon. If carbon is touched it will put current year fingerprints on the artifact. This is why tinfoil is used. To preserve the carbon. Another mistake that should never be made is mistakes with the line level and ruler. If the site is measured incorrectly all measurements will be off ruining all data.
A few points that should be remembered by an excavator are after each increment he/she should keep an eye out for a stratum change. Also, after each increment, take pictures. In the pictures the trowel should always be pointing towards the datum point. Also, it is important to secure the site with boards, tarp, plastic etc to protect stratigraphy and soil level. One more thing that should be remembered is if an artifact is sticking out of the walls of a site the soil underneath the artifact should not be touched. This could cause the walls to collapse and ruin stratigraphy. When the tools are used correctly, and methods of excavation are followed carefully excavation is a useful tool for digging into the past and uncovering cultures from past times.
Human and animal remains can tell us more about the past than almost any artifact. Bones are the most undeviating evidence we have with concern to human populations. Studying human remains can teach us about ancient burial practices, diseases and injuries of long ago, and about ancient DNA.A discovered skeleton can uncover the diet of the people of that era.
Nutrition may potentially influence skeletal form. By studying the teeth of a human skeleton can uncover the types of food eaten, whether it was meat or vegetation. A skeletons bone density, height and probable weight can also reveal their ancient diet.
To differentiate the bones of different species one should note different characteristics of the discovered items. For instance if a large thick bone is discovered to be crushed and broken apart chances are the bone belongs to that of a cow or other large animal whose meat was consumed by humans. The meat was probably smashed or cut then put in a stew to cook. These remains would often be found in a garbage pit of an archaeological site.Small thin bones found intact probably would belong to that of a rabbit, chicken or turkey. These animals would be prepared with the skeletal system ntact for the meat could be eaten around the bones. However, chances are these bones would not be found in close proximity together. They, too, would be found in a garbage pit on the premise assorted with the remains of other species.
Cat bones, as seen in the provided image, would show no signs of being part of a humans diet for they were domestic pets. However, they very well would not be found in a proper burial location but might be discovered in a garbage pit. Large bones with rounded ends, or joints, found in a proper burial spot almost certainly belong to a human being. Much can be told be investigating a human remains. The beings diet, cause of death, age, sex, and with today’s technology their probable facial appearance can all be determined.
They came from across an ocean to this rich, new land. They brought with them what they could
carry on their backs. With no prior knowledge of what lay ahead, they made use of what they found the animals, plants, water and stones. The stones would prove to be the most useful gifts of the land.
In the New England region the most abundant resource were rocks, and the earliest Americans used them for everything imagined. Projectile points were a very necessary part for such tools as knives, spears, arrows and harpoons. They were mainly made from flint. Many different sized and shaped rocks were used in shaping the projectile point. After a good-sized piece of flint was found, a rounded hammerstone was used to get the basic shape. Antler, bone, or ivory was set on the flint and hit with the hammerstone to chip away at the rock. Once the desired shape and sharpness was achieved, the projectile point would be tied onto the stick with sinew (tissue fibers); this method is called hafting. To ensure that the point would not fall off a notch would be made into the end of the stick and the point would be fitted into that.
These tools were used both in fighting and killing game. The most popular hunting tool at the time was probably the spear. It could be thrown great distances and penetrated the hide easily. As faster moving animals were being targeted, the accuracy and distance of the spear had to be improved. This was made possible by a new device called an Atlatl. The Atlatl was basically a medium-length handle on which the end of the spear was placed.
(atlatl and spear)
Sometimes a weight was put on it to give more power. The spear was launched from the Atlatl allowing improved hunting skills.
Cutting tools were constructed and used by the females. They were needed for preparing meals, and making clothes. The Ulu knife could be used for both of these purposes. First a hammerstone was used to accomplish the half circle shape. In order to chisel off the bumps she used a palm-sized stone with a semi-sharp point was used. Then the half-circle shape would be grinded and polished with a smoother stone. The blade of the Ulu knife was placed between two sanded sticks, which were bound at the ends.
A channeled gouge was used in cutting down trees to make canoes. The bottom of a tree was burned part way, and then a channeled gouge would finish the job of chopping down the tree. The channeled gouge was a thick branch with a small knob about two inches from the end. A wedge-shaped stone with a partial handle was tied to the end and the knob with sinew.
As tribes migrated from different areas, new customs were introduced to the native tribes. One new idea to come to New England was pipe smoking. There were three main shapes for pipes then, Platform, Straight and Elbow. They were made of a type of stone called Steatite. Spinning a stick between the hands, eventually drilling into the pipe made the hole.
As time passed the tools became more varied. For example, their drills could be found in many sizes. They were made almost the same way as knife and spearheads though they were smaller and thinner. Some different types were plain, t-base, tapered stem, eared, cross, diamond, and pipe bowl reamer. These not only differed in size but also in the shape of the base of the point and how it would be attached to a piece of wood.
Early fishing can be associated with modern day fishing with the ideas of harpoons and sinkers. The harpoons were not much different than they are now. They were composed of a projectile point hafted to a thick branch, which had a hole in it. Through the hole a rope was strung which ran to another branch, which the first was bound to with a breakable string. This allowed the harpoon head to come loose when it penetrated the fish. The fisherman would then pull it in by the rope and remove the harpoon head. Sinkers or Classic Plummets were heavy, oval shaped stones with a small knob on top to be tied to. They were very symmetrical for such primitive tools. The common stones for sinkers were sandstone and granite. A hook was sometimes hung from it to serve as a lure.
The evolution of the fishing ways changed, as did the tools. As time passed the harpoons were still in use and did not change too much besides now being made from antler or bone. The sinkers became larger and a little less care was put into making them. A new technology however was the fish weir. The fish weir was a large series of fences which were strategically placed so that fish could swim in but not out. The women now were smoking and drying the fish, which called for the production of drying racks.
Most of the archaeology in this area focuses on stone and bone artifacts. This is because the soil in New England does not favor wood and causes it to rot very quickly. Also, the natives new that wood was not very hard so the most important parts of their tools had to be made out of stone. Bone was useful but not as much as the abundant rock.
- Paleo-Indian tools- The Paleo-Indians came to New England in 8500 B.C. and stayed until 5000 B.C. The most well known projectile is the spear point; other well-known tools are the scrapers and knives.
- Fluted spear points- these are considered the paleo hallmark. The spear points were made out of imported flint from New York.
- Large stem scraper- This was used to remove the hair from the hides of the animal so that clothes and other hide products could be made.
- Paleo Knife- Archaeologists believe that this is the most important tool next to the spear. It had a variety of uses from the cutting of animals they had just killed to the making of their new tools.
Early Archaic Indians
The early archaic Indians were around in 5000bc to 3000 B.C. The changed New England brought new animals and new plants along with the new Native Americans. These Indians lived basically on caribou instead of mammoth and masterdon as its predecessors did probably their biggest breakthrough was the atlatl. An atlatl is made from bone hook, stone weight and a straight stick. The atlatl gave the thrower greater velocity and therefore greater distance seeing how the caribou were faster and more skittish then mammoths they did not need to get scared and ran away.
In fishing there was another major breakthrough for the Indians. The Early Archaic Indians developed harpoons and plummets. Harpoons were made with a long wooden shaft with a break off point that was attached to a rope. The break off point had barbs to keep it in the larger fish and water mammals. After it was stabbed with the newest harpoon it could be easily hauled in with the attached rope.
Plummet- It was a small stone with a notched end to attach the string to and two small bone hooks attached to the other end. The stone was used as a sinker and was rubbed with some kind of bait to attract the fish
The Early archaic Indians also made advances in the cutting tools, mostly knives. Now the knives had wooden handles and were made out of different stones that were smooth but maintained a sharper and keener edge. There were also new woodworking tools to make it easier to build canoes. The canoes were made from oak trees that the base of the tree was burned so that the tree fell. They then burned the side of the tree to make the tree hollow. They then hollowed out the charred wood.
Late Archaic Indian
The late archaic Indians made many new advances in everything from old woodworking tools to developing new ways of fishing. They also learned how to make stone bowls and pipes using a new material that was being imported from the Superior Lake region. The late archaic Indians were in New England from 3000 B.C. to 300A.D.
Stone bowls were made from Soapstone, a recent discovery. It was now possible to store liquids such as water, and cook foods such as stews that were previously impossible to cook. The bowls were made using a variety of new tools that had been adapted especially fro the making of stone bowls. They developed abrading stones, for smoothing out the bowls, triangle tailings and spade for mining the soapstone deposits.
Copper was found in the lake superior region. Before it was of no use because copper was brittle when cold and could not be shaped to make any use of. After the discovery that copper was malleable when heated over fire many old tools were now made out of copper such as axes and gouges for woodworking.
The Late Archaic Indians also developed fishing weirs that were made by using posts made out of saplings, and a net of woven reeds between the posts. The weir let the fish in during high tide and trapped the fish during low tide. At low tide they could just walk and grab the fish with their hands.
Ceramics woodland Indians: These were the Native Americans that old world explorers traveling to the New England. They were in this region from 300ad al the way up to 1676 ad. These new Indians were no longer nomadic and were finally settling down forming small villages. The Indians were now becoming agriculturally based and there for new tools had to be made for farming. They also made several advances in pottery.
They needed to clear fields for planting crops and they did this by burning the base of the tree out so that the tree was still usable for canoes and other tools. Then they used the new popular groove less axes that were also used as weapons. New tools were also developed for breaking apart the ground. The triangle hoe was made out of one piece of rock shaped triangularly; it was lashed on to a long pole.
Some of the most interesting finds today in archeology are the pottery artifacts. The three categories of pottery in the Anglo-American colonial world are earthenware, stoneware, and porcelain.
Earthenware is a water absorbent stone, which by putting glaze on makes it impermeable. Glaze that was used for earthenware was usually composed of lead sulfide, and it adds color to it. Normally pure lead is colorless and is transparent. Its firing point in the kiln is the lowest of all. When working on an archaeological site the most common objects found are earthenware.
Stoneware has a higher firing point than earthenware. It has hardness to it and is not a water absorbent material. Therefore it doesn’t need glaze on it but a salt glaze is often used. This gives it a smooth, easy to clean, glassy look.
Porcelain is made out of special clay called Kaolin. It is hard, translucent, and impermeable to water. It also has the highest firing point. Slip is decoration on the pottery that is made by white pipe clay, applied in liquid form, underneath the glaze; in the way you would decorate a cake. Other ways of decoration was using a rocker stamp, which is a shell. The edge of the shell was rocked back and forth, to produce a zigzag design. They also used sharp pointed rocks to make lines.
Pipkins are small, three legged cooking pots, made of earthenware glazed in green or yellow. The second period New England plates have come to be mostly of delftware and were large and elaborate. Delftware has a soft body and thick white glaze that covers it. It is painted with either blue or polychrome designs. Ceramic cups and mugs are very common after 1660.
The steps they used in making their pottery are the following:
- The first step in pottery making is the clay digging and powdering the clay.
- The second part is adding water and the tempering of crushed stones and shells.
- Third step is rolling out the clay into a coil shape, and also make a small base.
- Fourth step is to take the coiled shaped clay, and work it around the base to build up the sides. After that is done, take a wooden paddle and smooth up the outer and inner wall.
- The final step is to place the finished product in an open flame and allow it to cool down.
Radiocarbon dating is the process in which the carbon-14 content of a fossil or artifact is measured to determine the how old the artifact is. Comparing the amount of carbon-14 to the amount of carbon-12 in the artifact in order to determine how much carbon-14 has disintegrated since it had last been exposed to any organic material from a living organism does this. This method can place a relatively accurate age on objects dating back 60,000 to 70,000 years. In the case of a fossil, the carbon-14 decay is referred back to when the organism had died. Death causes the metabolic system to cease, thus stopping the intake of carbon into the body. Carbon-14 is an unstable atom and therefore signs of disintegration appear, while carbon-12 is a stable atom and shows no signs of decay. All organic material contains carbon-14, an element produced by cosmic rays from space. The origin of these rays is not yet fully understood.
Willard F. Libby discovered the method of Radiocarbon Dating in 1949. He had many theories about the isotope carbon-14’s role in metabolism of living organisms. When he found that measuring the radioactive decay of an organism could date organic material, his discovery immediately caused a serious commotion. Radiocarbon Dating was popularized as ‘the clock that runs backwards’ Many archaeologists stood by Libby’s discovery, such as Glyn Daniel, who described it as ‘Perhaps the greatest breakthrough in the development of archaeology’6
Yet others in the archaeological field felt that radiocarbon dating was unreliable, because it was registering dates that were thousands of years off what they had hypothesized. This was because many archaeologists were making simple mistakes in the excavation of these items. One of the problems with radiocarbon dating is that an error can occur in dating an artifact if the object comes in contact with any organic material, which is most commonly contact with human skin. This erases the original date, when it last came in contact with carbon-14 thousands of years ago, and replaces it with an age of zero. This mistake can also be made if a tool that has not been properly cleaned or is made out of wood touches the object. The correct way to handle an artifact that is intended for radiocarbon dating is picking it up with aluminum foil and storing it inside some sort of clean, metal container.
– ( artifact containing carbon placed in tin foil)
Although radiocarbon dating has made many advances since it has been introduced in the mid 1900’s, there is still a great amount of controversy directed at its reliability in dating archaeological discoveries. Recently, Radiocarbon Dating has become a key factor in the sensitive issue of religion. In 1988, The Shroud of Turin was sent to a laboratory to undergo radiocarbon dating, in order to reveal it’s true age. The Shroud of Turin is the piece of cloth believed to be what Jesus wore during his final days on earth. Followers of the Christian faith have valued the Shroud as a symbol of Jesus’s death and resurrection. But when the Shroud was tested, the carbon-14 in the linen of the cloth was dated no later than the Middle Ages. This drove many devoted Christians to believe that the radiocarbon dating was not a valid method for accurate dating, therefore widening the gap between the church and science. Other speculators of the Christian faith suggested that the cloth may have been tampered with in the Middle Ages, and that there is still a possibility Christ could have worn it. Either way, it is certain that radiocarbon dating has made its mark on society.
Potassium Argon dating bears great resemblance to that of Radiocarbon Dating. Using the same basic method of measuring, the decay of an unstable isotope is found on an artifact. The big difference between these two methods is that the half-life of potassium-40, the isotope used in Potassium Argon dating, is significantly longer than that of carbon-14; ranging somewhere around a thousand million years. An untouched sample of potassium-40 can date an object back to the beginning of mankind, when the earth was still in the early stages of its existence. Potassium is a much more abundant element on earth as well; it is found in nearly every mineral inhabiting the earth’s surface and crust.
When a potassium-40 disintegrates, it either turns into calcium-40 or argon-40. Argon-40, also an isotope with an exceptionally long half-life, builds up in minerals along with potassium. The proportionof potassium-40 to argon-40 can be measured to reveal the age of the artifact it inhabits. Since all organic materials are not potassium-based, potassium argon dating allows for less error in the laboratory or archaeological site. An archaeologist must be careful as to not contaminate the sample with argon build up in the earth’s atmosphere, where it is most commonly found. Also, there is a limited amount of minerals that can be used for this dating system, because of different argon isotopes that may be present in the object being dated. This method of dating, although quite difficult to perform due to its limitations, has become a great asset to archaeologists looking to delve deeper into prehistoric civilizations.
Dendrochronology is a method of dating that involves counting and measuring the rings of a tree to determine its’ age, and the history of the climate where the tree was living. The basic elements of this method have been around for hundreds of years, but it wasn’t closely examined until the late 1800’s. Andrew Ellicott Douglass, an astronomer at the Harvard College Observatory, adopted this study in 1894, while the Lowell Observatory in Flagstaff, Arizona, observing sunspots. In his experiments, he needed information about the climate in Arizona in the past hundred or so years. Mr. Douglass thought that tree rings might hold some of the clues he needed. By examining many different samples in the area around Flagstaff, he managed to amass considerable amounts of information on the history of the climate in that area. This led Douglass to pursue a great interest in tree rings, a field he was now pioneering.
Trees acquire a new ring every year. In the spring a tree develops a layer of large cells underneath the bark known as cabrium. By winter, the cells die, harden, and become wood. This process is repeated every year of the tree’s life. By examining the tree’s rings, one can tell what sort of climate the tree was exposed to the year that ring was formed. If the ring is thick, that means that it was a good year for growth, with healthy amounts of sun and rain. If the ring is thin, then the year may have seen a drought, or temperatures may have been colder than usual. Since trees near each other have the same tree ring patterns, you can compare a tree that you know the age of to a tree you do not know the age of by matching up patterns (See figure 1). This method has allowed dendrochronologists to date trees as far back as 59 B.C.
( Below is what the rings of a tree look like that Dendrochronologists study to dtermine diffrent weather patterns in a particular area)
During the mid 1500’s, pipe smoking became very popular in England. Although there was a limited supply of tobacco available at the time, clay pipes were inexpensive to make and therefore nearly anyone could afford to buy them. People disposed of their clay pipes after using them only a few times; this is why so many English kaolin pipe fragments are unearthed at archaeological excavations. These pipes were brought to America to be traded to Indians and colonies. This is why archaeological sites in the New England area usually contain thousands of kaolin pipe fragments.
With tobacco becoming more accessible, the bowl of the pipe became larger and the stem became longer. As technology in pipe manufacturing progressed, pipe makers found ways to make the hole in the stem smaller, allowing for less tobacco to go unburned. They did this by using a smaller bore to drill a hole in the stem. These are the bore sizes along with the time in which they were used:
Archaeologists have developed tools to measure the diameter of these holes. Edward J. Lenkin, an archaeologist from New Jersey, developed a tool called the “step gauge”, a steel rod that accommodates all six sizes. The instrument is pushed into the bore until it cannot go any farther, and then a measurement on the side of the rod tells the diameter of the hole.
Archaeological finds involving human remains have been most successful when the body is found in a marsh or a swamp, because chemicals in the bog water are able to preserve organic material for thousands of years. But a human corpse is not the only useful thing an archaeologist can find in a bog. Pollen grains from plants and trees can be preserved in bogs for many years and still maintain their original form and size. This allows archaeologists to understand what sort of plant life was growing during the period when the layer of bog they were studying was at the surface of the marsh.
Lennart van Post, a Swedish archaeologist discovered this method of dating in the early 1900’s. He found that if pollen were laid down on regular ground, it would decompose and be destroyed by microorganisms, or by chemical weathering. But if it is laid in a bog, the pollen does not decay and becomes somewhat of a fossil. This preserved fossil not only tells the history of the vegetation in that area, but also of the past climatic changes the environment has undergone. Patterns in vegetation that create a path along land may be a clue as to the migration patterns of certain animals or people who depend on that plant to survive. Thus, what seems to be a simple grain of pollen in a swamp may hold implications to the activities of prehistoric packs of animals and human societies.
Relative dating does not give archaeologists an actual date of an artifact. It is used to get a general idea of an artifacts age compared to other artifacts found in a site. Archaeologists can create a sequence of events by using relative dating.
Stratigraphy is a method of relative dating. It is the study of the layers of an archaeological pit. The deeper a layer is in the site, the older it is. Objects that are found at or near the top of the site are newer than those below it. Changes in soil throughout the pit allow archaeologists to easily form a sequence of events. They simply excavate and study one layer at a time, with all artifacts from that layer coming from approximately the same time period. If distinct layers cannot be seen in the soil of a pit, things can become difficult. The archaeologist is forced to rely on using levels of 1 to 10 centimeters. This may or may not produce accurate results.
There are several factors that can throw off the method of stratigraphy. Animals such as gophers, who dig in the ground, can disturb the soil. If a large hole had been dug on or near the site previously for a house foundation, soil may have been taken from the hole and deposited nearby. This causes deeper layers, which are the oldest, to settle near the top causing the archaeologist to believe they are the most recent, while excavating a site. Archaeologists are able to determine when this occurs by comparing their results to other excavations in the area.
Seriation is another type of relative dating. It is the study of artifacts popularity. It is typically done when there is no stratigraphy present in a site. While studying seriation an archaeologist looks at when an artifact was first introduced, when it reaches its peak in popularity, when the popularity declines, and when the artifact dies out completely. When population patterns are graphed they produce a battleship shaped curve. The bars start off narrow, grow wider and then they become narrow again. Some artifacts produce a pattern that lasts thousands of years while others only last a few weeks.
By using seriation, archaeologists can learn a lot of information about an archaeological site and other sites nearby. Seriation cannot determine the exact time period of an artifact or site or its length of use. It cannot tell archaeologists which artifacts or sites came earlier or later. It can only find its relative date.
Deetz did a seriation study in the 1960‘s. He studied three different styles of gravestones in New England cemeteries. The three designs were the death head, the cherub and the urn and willow. Gravestones are dated, so Deetz was easily able to have an accurate study. In his study he found that the death heads came about first, followed by the cherub, and then the urn and willow became the prevalent design. He found this pattern overwhelmingly present in hundreds of New England cemeteries. When his data was put into a bar graph it formed a near perfect battleship curve.
Archaeology Is a complex and highly intellectual science. Through Archaeology we satisfy curiosity and thirst for knowledge. Archaeology presents many answered questions and more questions in the end then before that site was started. It helps us to figure out where we’ve been, and there for since history tends to repeat it shows us our path into the future. Archaeology ties nations together and breaks them apart ( I.e. The pyramids in egypt started many conflicts over countries breaking in to them and looting them). Mans interest in archaeology is for ever expanding and will never be quenched.
(Below: Chart based on finial and border data.)
|URN & WILLOW|
|1690- 1729||1730- 1750||1751-1780||1781-1820||No Date|
|1690- 1729||1730- 1750||1751-1780||1781-1820||No Date|
|5 Petaled Rosette|
|1690- 1729||1730- 1750||1751-1780||1781-1820||No Date|
|Erected in Memory|
|Departed this Life|
|Sacred to the Memory of|
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