Monday, March 29, 2010

How geology affected both ancient and modern human settlements.

Primitive tribe were attracted towards the forest and hilly terrain of Jharkhand state, India.
Dr. Nitish Priyadarshi

Geology has a remarkable influence on our lives today, as it has on all life since the beginning billions of years ago. Perhaps the clearest influence we see of this is through the development of wealth from the exploitation of fossil fuels and mineral resources, including precious metals and gems. Wars have been fought over (and with) these resources, and for the potential wealth they represent. However, geology has other profound, if less glamorous, impacts on civilization, both past and present. For example, the productivity of soils critically depends on the underlying geology—both for its mineral composition and its capacity to store water. Geology also determines the shape of our landscapes—that is, before being disturbed by humans—and it is the shape of the land that has determined the distribution of human populations throughout our history.

Back at the dawn of human civilization when we lived along the Nile, the river regularly flooded and would bring nutrients and minerals back to the croplands. That is what sustained early human civilization. The dawn of agriculture was dependent on the flooding of a river. Had that river not flooded and that land been farmed over and over again from generation to generation, the civilization there would have died due to malnutrition. It could not have sustained itself.

The origin of urbanization had been sought from speculations and deductions of observable facts. The first cities must have originated from the development of settled agriculture, where agriculture economy in which the cultivation of cereals was an important element.

The first civilization originated along the river valleys as the water played major role in both day to day life and in agriculture.

The earliest examples of the urban development originated on the bank of the Tigris and the Euphrates between 5000 to 3000 B.C. Various technological inventions such as the wheeled cart, ox-drawn plough, sailing boat, system of canal irrigation, development of pottery and metallurgy brought changes in the economic and social organization.

The main geological factors influenced the ancient urbanization are as follows:-
1. Nature of the topography.
2. Local weather conditions.
3. Availability of water.
4. Quality of soil.
5. Nature of surface and sub-surface water.
6. Presence of minerals and rocks.

The influence of these factors varied from time to time in various forms and on the sizes of rural settlements.

Certain factors were considered by our ancestors when the site was selected for settlement such as availability of water, high ground in easily flooded areas etc. Japanese farming villages for example are tightly packed together, so that only the narrowest passage ways remain between the houses. This reflects the need to allocate every possible square meter of land for farming.


In early period people led an insecure life especially in the border areas. In such places the settlements were either located on top of a hill or in the meander loop of a river or on high place near valleys to assure protection. Hills and mountains also provided caves to early settlers as their natural home.

Durham in England was built on a hill protected on three sides by the meander of the river water. Pithoria, near Ranchi city in Jharkhand State of India, was also selected as the earlier capital town (1st century AD) by Munda tribe because from one side there is steep valley and from other side it is covered with hills. It acted as natural protection from the invaders.

Pithoria was also rich in ground water reservoir which also attracted the early settlers like Munda and Nagvanshi rulers to develop this area as their first capital.

Rocks as building material:

Rocks were earlier used as the building material especially sandstone. Many such ancient buildings and temples are found in India where sandstone and granites were used.

Sandstone has a long history in the building industry. The stone generally has a uniform texture and it is somewhat soft, making it a user-friendly stone for a variety of applications. It is favored for wall claddings because of its low absorption rate, high compression strength and aesthetically pleasing appearance. Its appearance and high durability make it ideal for flooring as well. With a variety of colors and finishes, it is also easy to match it to nearly any décor.Massive sandstones consisting of closely interlocking and angular grains and free from structural defects were found best for building purposes. Most of the sandstones used in the buildings in ancient city of Varanasi in India, may have been supplied from Vindhyan System. The Vindhyan sandstones are fine grained in texture and available in abundance in a variety of colours like white, cream, and deep red and grey etc.Vindhyan sandstones are regularly quarried in area very near to Varanasi in Uttar Pradesh.

The stone is a common paving material because it can be highly weather resistant. Due to such quality these stone was used in mass scale in constructing stairs near the banks of the holy river Ganges in India. As a paver, sandstone is prized for its ability to maintain age and appearance over time, as well as for the different dimensions available.
Sandstone pavers can be used for patios, pool surrounds, pool coping, balconies, as well as cladding and veneer.
The color of sandstone is extremely varied and depends on the quantity and color of the cementations materials present and the overall color of the mineral grains. Sandstone spans the full spectrum of colors, ranging from sandy yellows to deep gold, pale pinks and light greens.
Light colors generally result from the absence of cementitious materials, or joined by calcite or quartz. Buff, brown and red colors result from the presence of limestone and hematite. Greensand, a type of green sandstone, results from the presence of glauconite.


Perhaps the essential ingredient to any viable civilization is access to water. Nearly all the great civilizations the world grew up around water, which provided the key not only to supplying freshwater, but also to agriculture, trade, transport and defense. Such civilizations as the Roman Empire, Egyptian Civilization, the Venetian Empire and the Omayyad Dynasty were all founded on their access to water, which provided their population with the means to both survive and expand.

Water is a vital need and man from time immemorial settled nearer to the source of water. In some places especially in limestone region people select the spring locations the site for settlements. These springs occur in a line at the line of contact of the permeable and impermeable layer. Such settlements are referred to as spring line settlements e.g. spring line villages are seen in South Dover in England and in Jammu and Kashmir State in India.

In dry areas settlements have the tendency to get oriented nearer to the sources of water. Hence the settlement site was located near a spring or river. These settlements were found ore are found in the dry limestone and other regions as well as in deserts.

World's major ancient civilizations flourished near river banks and deltaic sea coasts. The reason behind is the easy availability of water, a vital requirement of human beings. However, this choice of sites with easily available water has also cost dear to them. The change of river courses and sea level fluctuations led to the devastation of well-established civilizations. The drowning of ancient settlements due to raised sea level, forms the common subject matter of interest to marine archaeologists and marine geologists. While, marine archaeologists pay more attention to cultural aspects of those ancient people, marine geologists are interested in sea level fluctuations that cause the rise and fall of these civilizations. Marine archaeologists make use of artifacts, whereas marine geologists utilize the sediments and marine organisms to unravel the past. Since the common aim of both, the marine geologists working on palaeoclimate and the archaeologists is to illuminate the past, it becomes necessary to bring coherence between the two. In the Indian context, some attempts were made to use the understanding of sea level fluctuations to explain the archaeological discoveries. Nigam et al. (1990) collected the evidences of sea level fluctuations from religious, archaeological records and successfully supplemented with inferences from the marine geological studies.

Discovery of Lothal dockyard (first naval dockyard of the world as claimed by archaeologists) in Gujarat and drowning of Dwarika on the west coast and Pumpahar on the east coast of India are important examples of the role of the sea level fluctuations in shaping the history of mankind in this part of the world. The discovery of the Lothal dockyard, an important and famous name in Indian cultural heritage, provides evidence of ancient Indian interest in maritime activities around 4500 years B.P.

The Ganga-Ganges, especially, is the river of India, around which are intertwined the countries memories, culture and history. She has been a symbol of India's age-long culture and civilization, ever changing, ever flowing, and yet ever the same Ganga-Ganges.

The history of Ganga-Ganges is as long as the history of Indian civilization. It was in this plain that the great kingdoms of Magadha, Gupta, and Mughals found their home. It is also the region that created one of the most homogenous cultures of all times in the civilizations of the world. It was also the place which created the essence of Hinduism, Buddhism, Jainism, and Sikhism.

In the low lying areas and the delta areas, which were prone to floods and in the equatorial regions where damp and marshy conditions prevailed, settlements had the tendency to seek dry sites. Generally the hill site some 30 m above the surface land were preferred. Still today they are following the same pattern. Such settlements are known as dry point villages.

The foot hill region offers some possibilities for settlements. The foot hill region has the advantage of collecting products from the mountains as well as from the adjacent plains.


Volcanoes are also playing major role from ancient civilization to present. Volcanoes are known for their violent eruptions and lava flows, but there are many benefits that volcanoes provide for society. Volcanoes help enrich soil for farming and in some cases provide reservoirs for the storage of ground water. Moreover the earth's valuable resources are formed in volcanoes. These elements include fluorine, sulfur, zinc, copper, lead, arsenic, tin, molybdenum, uranium, tungsten, silver, mercury, and gold. Society makes use of all of these elements that volcanoes help to provide. Geothermal power is an alternate energy source that is better for the environment and volcanoes provide this to society also. Although volcanoes have the reputation of being very dangerous, (Volcanoes can kill people and animals. They can be very destructive.) There nevertheless are advantages of living near a volcano.

When a volcano erupts it throws out a lot of ash. At short notice this ash can be very harmful to the environment, but on the long term the ash layer, which contains many useful minerals, will be converted to a very fertile soil.

Close to an erupting volcano the short-term destruction by pyroclastic flows, heavy falls of ash, and lava flows can be complete, the extent of the damage depending upon the eruption magnitude. Crops, forests, orchards, and animals grazing or browsing on the volcano's slopes or surrounding lowland can be leveled or buried. But that is the short-term effect. In the long run, volcanic deposits can develop into some of the richest agricultural lands on earth.

One example of the effect of volcanoes on agricultural lands is in Italy. Except for the volcanic region around Naples, farming in southern Italy is exceedingly difficult because limestone forms the basement rock and the soil is generally quite poor. But the region around Naples, which includes Mount Vesuvius, is very rich mainly because of two large eruptions 35,000 and 12000 years ago that left the region blanketed with very thick deposits of tephra which has since weathered to rich soils. Part of this area includes Mount Vesuvius. The region has been intensively cultivated since before the birth of Christ. The land is planted with vines, vegetables, or flowers. Every square foot of this rich soil is used. For example, even a small vineyard will have, in addition to grapes and spring beans on the trellises, cauliflower and onions between the trellis rows, and the vineyard margin rimmed with orange and lemon trees, herbs, and flowers. It also is a huge tomato growing region.

The verdant splendor and fertility of many farmlands of the North Island of New Zealand are on volcanic soils of different ages. Volcanic loams have developed on older (4,000 and 40,000 years old) volcanic ash deposits of the Waikato and Bay of Plenty regions. Combined with ample rainfall, warm summers, and mild winters, these regions produce abundant crops, including the kiwifruit found around the world in modern recipes. The altered volcanic ashes are well-drained, yet hold water for plants, and are easily tilled. Deep volcanic loams are particularly good for pasture growth (there is a large New Zealand dairy industry), horticulture, and maize.
Nearly everywhere volcanoes are located people use the rich soil for farming. Even after an eruption people still return because of the fertile soil around the volcano.

Rocks and minerals:

In ancient days rocks and minerals played the important role for the earlier settlements. Best example is that of Jharkhand State of India, where the primitive tribe like Asur and Birhors were attracted towards the forest and hilly terrain of this state. Causes may be the presence of minerals and stones. Iron-smelting used to be the principal occupation of the Asurs. Asur used to extract iron ore for iron smelting from the laterite rocks present in this state.

A study of the early iron technology of Bihar, Jharkhand and West Bengal state in India, is of special importance from the point of view of proper understanding of the nature and character of iron age cultures which developed and flourished in this region during the period ranging from protohistoric to the historical period. The early beginning of the use of iron in this region was initially noted in the late Chalcolithic cultural phase.

Since the beginning of civilization, people have used stone, ceramics and, later, metals found on or close to the Earth's surface. These were used to manufacture early tools and weapons, for example, high quality flint found in northern France and southern England were used to create flint tools. Flint mines have been found in chalk areas where seams of the stone were followed underground by shafts and galleries. The mines at Grimes Graves are especially famous, and like most other flint mines, are Neolithic in origin (ca 4000 BC-ca 3000 BC). Other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District.
The oldest known mine on archaeological record is the "Lion Cave" in Swaziland. At this site, which by radiocarbon dating proves the mine to be about 43,000 years old, paleolithic humans mined mineral hematite, which contained iron and was ground to produce the red pigment ochre. Mines of a similar age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons and tools.

The study of rocks and minerals is one of the taproots of science, perhaps not as deep as astronomy, but extending well back into prehistory. Paleolithic people recognized and sought specific rocks and minerals for cutting tools, pigments, and various practical, religious, or artistic objects. The first minerals that were known and sought for their favorable properties were micro-crystalline ( micro crystalline means too small to be seen without a microscope) varieties of quartz, particularly flint.

NIGAM, R., HASHIMI, N.H. and PATHAK, M.C. (1990) Sea level fluctuations: Inferences from religious and archaeological records and their oceanographic evidences. Jour. Mar. Archaeol., v.l, ñp.16_18.

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