Archaeology pieces together the past, little by little, in an attempt to complete our history's jigsaw puzzle. Because it is such a broad subject, it has many disciplines and specializations based on the time period studied, the civilization studied, or the types of artifacts and features studied. And because of the slow nature of the recovery of historical artifacts and remains from archaeological sites, it is common for archaeologists to devote their lives to only one branch of study.
The following are a few areas of specialization:
Prehistoric archaeology focuses on all the pre-urban societies of the world - the civilizations that had not developed writing yet nor kept any historical records. In Western Europe the prehistoric period ends in 43 AD. However, with some non-Romanized areas the period does not end until the 5th Century AD.
This branch of archeology has very close links with biology, biological anthropology, and geology.
Without written history to provide evidence for names and places, prehistoric archaeologists often give arbitrary modern names to cultures, which directly relate to the location of where artifacts are found.
For example, arrowheads (or projectile points) and stone tools that were found in Clovis, New Mexico have given prehistoric archaeologists clues as to how the people in that area lived their lives. Because these artifacts were found in Clovis, the culture was named after the town, and are known as the Clovis people. The Clovis people are now known as one of North America's first inhabitants, dating back 13,000 years ago.
Historical archaeology is a mix of history and anthropology. It focuses on the cultural processes and human experiences of everyday people in recent history. These experiences have produced the world we live in today, and through studying the writings and recordings of information by past societies, we are able to understand the emergence and transformation of today's modern world.
In a nutshell, historical archaeology involves the study of literate, historical societies as opposed to the non-literate prehistoric societies. It is the study of past societies that also left behind historical documentary evidence.
An example of this is the Rosetta Stone that was discovered in Egypt in 1799. The stone was inscribed with a decree in three different languages (hieroglyphic, demotic, and Greek) and has become an important tool in historical archaeology and has contributed to our understanding of Egyptian history.
Another example is the discovery of the Dead Sea Scrolls, a collection of approximately 900 documents that were found between 1947 and 1956. These writings date from between the third century BCE to the first century CE and are the oldest versions of Biblical texts ever found. Discovery of the scrolls has increased our knowledge of the development of Judaism and Christianity.
Historical archaeologists are particularly interested in books, engravings, manuscripts, seals, drawings etc. These types of archaeologists often work closely with historians.
Biblical archaeology focuses on the recovery and scientific study of the material remains of the Holy Lands (in the Middle East) in order to shed light on the periods and descriptions in the Bible. These types of discoveries have assisted to illustrate and corroborate biblical texts from the Old Testament (Hebrew Bible) or from the New Testament, as well as the history of Judaism and Christianity.
Note that Near Eastern archaeology deals with the Ancient Near East, or Middle East, without specifically focusing on whether discoveries have any relationship with the Bible. The scientific techniques used by biblical archaeologists are the same as those used in general archaeology, such as excavation and radiocarbon dating.
Paleopathology is a subdiscipline of prehistoric and historic archaeology, and plays an important part in understanding past populations. It is the study of disease in ancient cultures, and contributes to our understanding of how modern diseases progress.
From the Renaissance to the mid-nineteenth century, there was more of an interest in learning and understanding ancient diseases, therefore the importance of studying the history of human disease began to be emphasized.
Paleopathologists may study how different communities in the past reacted to disease, what areas lacked certain diseases, and how healthy certain communities were. By studying the teeth of ancient people, paleopathologists can decipher how often they ate, what types of food they ate, and the nutrients those foods contained.
Paleopathologists also analyze the condition of bones to determine what sort of diseases individuals may have had. Infectious diseases such as tuberculosis, leprosy, and syphilis can be found inside bones. By looking at the paleopathology of certain diseases, one can determine if the disease has carried through and is still present over time, or if this disease is no longer, and why it does not exist today.
Ethno-archaeology is a branch of archaeology that focuses on understanding the hunting and gathering activities of today's living groups of hunter-gatherers in Australia, Central Africa and the Arctic.
Ethno-archaeologists observe these living cultures in their natural environment and compare their characteristics and behaviour to their ancestors (such as those who lived during the Neolithic period) to see if they perhaps share some aspects of each other's ways of life.
These types of archaeologists spend a lot of time amongst the hunter-gatherer groups they are studying. They study their daily activities, behaviours, artifacts, hunting tools, discarded food, rubbish pits, and abandoned settlements and keep detailed records so as to compare them with patterns observed in excavated archaeological sites from the past.
They hope that by studying how these people use and organize objects today, they can better understand how people used tools in the past. They also hope to understand the accumulation of artefacts found at excavations sites, and the associations between tool making and the slaughtering of animals.
Environmental archaeology is a discipline that has grown very quickly in the past 50 years and is an important part of most excavation projects.
Environmental archaeology (sometimes called human paleoecology) focuses on the environmental conditions that had an effect on people in the past, and attempts to put together the relationships between past societies and the environments they lived in. Doing this provides environmental archaeologists with a look into the origin and evolution of environments, prehistoric adaptations, and economic ways of life.
Environmental archaeologists often work closely with paleoecologists and anthropologists, studying plant and animal remains so as to uncover what types of plant and animal species were living at the time of prehistoric habitations, and how people living during those times managed them.
For example, it's been discovered that the growth of the Brazilian highlands people (the Taquara/Itararé people) is closely tied with the growth of the evergreen forest in that area. As the forest grew, the people were provided with more resources (plants, animals, and timber), hence the growth of the people and their territory.
Underwater archaeology is a fairly new discipline that explores and examines shipwrecks and materials at the bottom of both shallow bodies of water (such as lakes and rivers) as well as deep oceans. Underwater archaeology also uncovers and studies water-buried cities (caused by sea levels rising or by earthquakes) such as portions of the ancient city of Alexandria, Egypt.
Both prehistoric and historic periods are studied in this discipline. By using sophisticated equipment (such as sonar, remote controlled cameras, and remote controlled salvage vehicles), ancient civilizations that have been underwater for centuries can be discovered. Special methods to preserve perishable materials are used, involving the latest synthetic processes, in order to conserve the artifacts.
In ancient times, ships were the main mode of transport, especially for trade. Many ships carrying full cargo and crew have been lost at sea due to storms and rocky shallow waters. These shallow water shipwrecks reap a plethora of sunken treasures in the form of food items, weapons, cups, plates etc., which helps to piece together the puzzle pieces of past cultures.
One of the most famous shipwrecks, the Titanic (which sunk in 1912 and killed 1500 people), was located in 1985 using remote-controlled cameras. Hundreds of artifacts (toys, furniture, lighting etc.,) were found, as well as discovering that the ship had broken into two pieces as it sank.
It goes without saying that there is a high level of danger that is involved with this type of work. Using robotic divers that have strong lights and cameras attached to them helps greatly when working at low depths and with little visibility.
Forensic archaeology involves applying archaeological methods in order to investigate and reconstruct a crime, usually a murder. Forensic archaeologists, or forensic anthropologists, help to identify human remains. Archaeological methods are sometimes used to assist in the excavation of human remains - the process is very similar to that used by traditional archaeologists when recovering remains from the past.
Forensic archaeologists are sometimes commissioned by organizations such as the UN to investigate mass graves in order to gather incriminating evidence for war crimes.