DISCUSS THE RELATIONSHIP BETWEEN ARCHAEOLOGY AND GEOLOGY.(Ay 304)

For several centuries the study of geology has been fundamental in answering various questions in archaeology. As such archaeologists have not only been contingent to the discipline of geology but have proved it to be useful in their various archaeological researches. Its extreme was reached in 1976 when the term Archaeogeology was, for the first time, used by Colin Renfrew to describe the contribution of the geological sciences to geology. (Norman and Evan 1998:20).

To monument the importance of geology in archaeological tasks, the geological society of America (GSA) established the Archaeological Geology Division in 1977, whose purpose was to provide  suitable forum for presentation of papers on archaeological geology and to stimulate research and teaching in archaeological geology. The earlier documentation of the influence of geology in archaeology is believed to have started in 1830 when Charles Lyell published his Principles of Geology. In 1863, he published his famous book Te Geological Evidence of the antiquity of Man, in which he used geological context to document the remains and artifacts of early humans.

It is from such pretext that this paper attempts to analyze the relationship between archaeology and geology, a study that, among other things, aims to illustrate the extent to which the discipline of archaeology has benefited from the study of geology at large. For the purpose of this discussion, two major terms are also going to be examined; Archaeology and Geology.

According to Fagan (2009:4), Archaeology is the scientific study of the human past, of ancient human behavior, from the earliest time right up to the present. As such, archaeology is part of wider discipline of archaeology which studies all aspects of humanity, ancient and modern. But archaeologists are unique among scientists in that they study changes in human culture over long period of time.

On the other hand Collin and Paul define archaeology as partly discovery of treasures of the past, partly the meticulous work of scientific analyst, partly the exercise of the creative imagination. Archaeology then is both physical activity out in the field and an intellectual pursuit in+ the study of laboratories. (Renfrew and Bahn 2008:12)

By and large, the study of archaeology is concerned with analysis of human culture by using cultural remains and other cultural phenomena.

Geology can be defined as the study of solid Earth, the rocks of which it is composed, and the process by which they change. Geology can also refer to the study of the solid features of any celestial body. It gives insight into the history of Earth by providing the primary evidence for plate tectonics, the evolutionary history of life, and past climates. Geology has been divided into two major groups namely; planetary geology and applied geology. (Lidell, et al. 1996)

Planetary geology has to do with exploration of other planets i.e with the advent of space exploration in the twentieth century, geologists have begun to look at other planetary bodies in the same ways that have been developed to study the Earth. This new field of study is called planetary geology (sometimes known as astrogeology) and relies on known geologic principles to study other bodies of the solar system.

Applied geology is the geology that is used in various areas of practice including mining, engineering, hydrology and environmental issues and, in due course, archaeology.

According to Norman and Evan (1998:20), in their book, Geological Methods for Archaeology, geology covers substantial roles in various archaeological processes as follows;

Geology facilitates archaeological sites exploration. The first decision that must be made in any new archaeological program is where to dig. In many cases, the decision can be based on historical records, by the visible remains of ancient construction, or by the discovery of abundant artifacts. However, to see deep enough into the surface so that decision can be made on specific target areas for excavation, and also to obtain an idea of what artifacts and constructions to expect, techniques involving geology are increasingly used.

Analysis and interpretation of archaeological site and its environment. In archaeological studies, landscapes and environment can be recreated through studies of geomorphology and sedimentology embedded in geology. As such, geology is used to analyses the deposits found in the surface that provides much of the evidence for changes in land forms over time. These deposits may be residual materials , formed in place by weathering of underlying formations, or may have been formed elsewhere and then transported by wind, water, or humans to their present site of deposition. The kind and amount of surficial materials change with changing land surface and climatic conditions and so offer the est evidence regarding the evolution of the landscape. An understanding of these changes on a site will allow re-creation of the palaeoenvironment at the time of occupation and modeling of the prehistoric land-use patterns. Archaeological exploration in an area is facilitated by first pinpointing desirable habitation sites of the time and then targeting these sites for geophysical and geological prospecting.

Excavation process, geology and geomorphic-sedimentologic information can help develop excavation strategies. Such information commonly allows a better idea of the distribution and nature of buried artifacts and may explain anomalous surficial redistribution of artifacts, for example, by downslope wash or sediment burial. In doing that three major phases are involved; Geomorphic mapping that provides descriptions of the landforms, drainage pattern, surficial deposits, tectonic features and any active geomophological process; analysis of the erosion process that carved the land forms-including soil formation, sediment removal or deposition and tectonic uplift-are documented; the land-forms, climate, and surficial deposits of today are extrapolated back to reconstruct palaeoenvironmrnt and palaeoclimate at the time of the occupation of the site.

Geology helps in archaeological artifact analysis since it can be used to determine the sources of raw materials used in the artifact. For example, the development and spread of iron technology were clearly evident in the production of pots at different sites in the Tigris-Euphrates Valley beginning about 5500BC. The designs were universally used and emanated from single sites, so that archaeologically it appeared that the pots were being exported from those sites. However, since the materials used at each site were determined to be local, technology was exported not the pottery. Each site must have had its own production center, which took advantage of the raw materilas: it also must have had a representative of the “head office” to ensure quality and artistic control. (Norman and Evan 1998:20).

Both archaeology and geology use various dating techniques in obtaining both absolute and relative dates of various materials. The methods used in dating can be explained through various laws or principles that include;

The principle of Uniformitarianism , this was a fundamental principle of geology advanced by the 18th century Scottish physician and geologist James Hutton. The principle states that the geologic processes observed in operation that modify the Earth's crust at present have worked in much the same way over geologic time. In Hutton's words: the present is the key to the past and the past history of our globe must be explained by what can be seen to be happening now.

The principle of intrusive relationships. This principle concerns crosscutting intrusions. In geology, when an igneous intrusion cuts across a formation of sedimentary rock, it can be determined that the igneous intrusion is younger than the sedimentary rock. There are a number of different types of intrusions, including stocks, laccoliths, batholiths, sills and dikes. Such principle can be applied in archaeology to determine the age of sediments.

The principle of cross-cutting relationships. This dating principle pertains to the formation of faults and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether the fault is a normal fault or a thrust fault. In archaeology, this principle enables dating of artifacts found in such fault rocks.

The law of superposition. This law states that a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of vertical time line, a partial or complete record of the time elapsed from deposition of the lowest layer to deposition of the highest bed.

Stratigraphy can also be used to determine relative age of various remains.  This is done through analysis of  stratigraphic position, style and absorption of transient elements. Objects found in the same undisturbed stratigraphic horizon are perceived to have the same age, those in a lighter horizon are perceived to be younger, and those are perceived to be older.

Both Archaeology and geology can be used to understand past events. For example, through the study of Geology, Geologists may come up with the list of prominent events thst must have influenced sediments and or rocks causing them to change from one shape to another. On other hand, Archaeology also is used to understand past events, this is done through analysis of artifacts, ecofacts, structures and features.

However, the two studies; Archaeology and geology differ in various ways as illustrated below;

Geology deals with analysis of both Earth and other planets in its branch of planetary geology. However, Archaeology, up to this moment focus on analysis of materials found on Earth and this is particularly because Archaeology is concerned with knowing past human culture who are perceived to be found on Earth alone.

Geology primarily studies the Earth, solid materials and rocks. They work to understand the history of the Earth. Archaeology, on the other hand studies humankind by using artifacts and remains that can be found in the ground by ancient humans. (Lidell, et al. 1996)

Archaeology deals with analysis of both organic and inorganic materials, that is to say it deals with both modified and unmodified remains which include the remains of animals and plants. On the other hand Geology deals with inorganic materials that include rocks and in no way includes animals and plants.

Finally, it can be said that Archaeology and Geology are closely related disciplines. As such, not only is it impossible to conduct archaeological process without Geology, but the whole process of conducting archaeological excavation requires knowledge of Geology. It is from such understanding that Colin Renfrew in 1976 established the term Archaeogeology to combine the two disciplines as they were seem to be inseparable from one another.  

                                                       

                                                             REFERENCES

Fegan M (2009) Archaeology: A brief introduction. California. Prentice Hall press.

Levin, L (2010) The earth through time (9th ed.). Hoboken, Oxford University press.

Lidell, G (1996). A Greek-English lexicon. Oxford, Oxford University press.

Norman H, and Evan G (1998). Geological Methods for Archaeology, Oxford, Oxford University press.

Olsen, E (2001). "Steno's Principles of Stratigraphy". Dinosaurs and the History of Life. Columbia. Columbia University press.

Renflew, C and Bahn, P (2008) Archaeology: Theories, Methods and practice. Oxford. Thames and Hudson publishers.

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Reijer, H (1963) Natural Law and Divine Miracle: The Principle of Uniformity in Geology, Biology, and Theology, Leid-en. EJ Brill press.