***FW a socio-economic change, a bridge needs to be established between geology and other applied and engineering sciences, writes Dr Aftab Alam Khan***

SINCE the dawn of civlhs

•Don people have been filled with curiosity about the earth on which they ttw Why does a volcano erupt? What causes an earthquake? What is the source of water that bubbles up in a spring? Why do some streams have quick-sand on one bank and solid rock on the other? What controls the beautiful geometric forms of snowflakes and other crystals? Why does one well yield water in abundance whereas another of the same depth is dry"?

As man's curiosity led him to seek answers to such questions. he often found that he was faced with new riddles. Man attempted to solve such riddles. But the first roots of man s knowledge of the earth are lost in antiquity. The early Greeks and peoples of other early civilisations made some progress in geologic at study, but their ideas were based largely on untested speculations and little has survived. The modern science of geology is of comparatively recent origin. The word geology ' itself is less than 200 years old. Despite its youth, however, geology has already done much to stimulate and unshackle the thinking of mankind. One would probably say that geology is a science, just because it is popularly so described, but could this statement be defended? What sort of activity is it that we call -science" — so forbidding to some people, so fascinating to others? What do geologists do that makes them think of themselves as scientists?

One can have the test of geo logic reasoning sitting on a sea cliff and wonder about what is happening to it. what it had

looked like in the past and what it might look like in the future. The goal of geologists in their work, is to apply similar reasoning to other parts of our natural environment, to ex pfore its nature and history to predict its future, and to con aider ways in which man can use and abuse it.

Although geology is a complex and varied subject, it is also a stimulating ar id interest ing one. Many geological problems require supplementary investigations using techniques borrowed from other sciences. Geologists are constantly learn ing from chemistry, physics, mathematics and engineering, new methods, data, and theories that can be applied to earth problems. Because of the complexity of its problems, and the range of the phenomena with which it deals, geology has not advanced so rapidly as chemistry. physics or mathematics The geologist cannot move a volcano into the laboratory to. observe the growth of Its cone; nor can he spread a bed of peat on the laboratory table watch its development into coal for millions of years. Yet these are among the simpler phenomena of geology. Factors of size and time make experimental study of many geologic processes difficult. and often, impossible. Faced with these apparently insurmountable difficulties, geologists have had to devise ingenious. indirect methods for getting the answers to many of their questions. A geologist collects rock specimens with

his hammer, he looks at them in the field with his lens and then he brings them back into the laboratory and subjects them to all manner of tests with a variety of sophisticated instruments. Even in the field he supplements hammer and lens with other gadgets like com pass. maps, aerial photographs and instruments for measuring various properties of rocks, soil and water

The increasing use of instruments from other sciences blurs the definition of geology If somebody spends most of his time in the laboratory analysing rocks by using the techniques of mass spectrome try. atomic absorption, and neutron activation, what exactly is he practising — geology, or chemistry or physics? This depends on the kind of question that such an analyst is trying to answer. The factors of com plexlty and diversity, together with the newness of the science, combine to make geology a vigorous. rapidly expanding field. In nature, a geologist acts as a sleuth. He is forever trying to look behind the surface of things, to detect the processes that are working to change the appearance of rocks and landscapes.

In the language of evolution, man Is an animal well adapted to his environment. The "environment'' here means most of the land surface of the earth, for man has shown a remarkable capacity among animals for living in a variety of habitats —

from the bleak coasts of the Arctic Ocean to the rainforests ol Brazil and Central Africa, from the high plateaus of Tibet to the hot. arid deserts of Arabia. The extremes of adapta tion are possible because of man s unique ability to use his environment, to find and mod Ify the materials he needs for food and tools and protection. The materials he seeks have been fashioned for him by the geological and biological processes that have shaped the sur face of the earth. From a strictly human standpoint, then, the most Important of all geologic questions is the efficacy with which useful sub stances have been produced and concentrated over long periods time by erosion, sedimentation, volcanism and tectonic activity.

How effectively have useful materials been concentrated In nature? One can ask such a question on two levels: the ob vious query about the local availability of needed materials to a community or a nation, and the broader problem of the sufficiency of earth materials to satisfy the long-time needs of the race as a whole. For most of human history the ultimate ad equacy of resources seemed obvious. In modern times, with the explosive increases in population and the ever-growing need for raw materials in huge auantltles to maintain an in-ustrial civilisation, that a query about overall planetary resources has become pertinent To change our sights from the

urgent problems of day-to-day living to a concern about the future of humanity is a big jump. Too often the Jump is largely emotional. We see pictures of humanity Juxtaposed with pictures of oil tankers or exhausted mines or eroded soil, and we read frightening statistics comparing population trends with rates of depletion of resources, and suddenly the prospect of our future generation eking out a savage existence on an exhausted and crowded planet seems very real.

Radical solutions like halt Industry ", "close down mines", recycle everything possible", go back to simpler ways of life" sound attractive A more sober second thought suggests that such a solution would be monstrous. for just the simple maintenance of the world s population depends on the In trlcate network of production, fabrication, transportation, communication and luminous environment to which we are accustomed. The success of production fabrication, trans portation and communication mostly depends on the sound environmental condition. Recurrent floods, droughts, frequent landslides, depletion of surfacewater and groundwater, toxic contamination of groundwater, deterioration of river morphology probability of the occurrence of a devastat’ ing earthquake once in a blue moon can obviously act as an triggering agent for the total misery of mankind and for the ever recovered distressed socio-

economic conditions.

As a conscious citizen — ef fective planner. balan<— ' maker aIij icspon-•xuk administrator should we not extend our realisations for an effective, balanced and sustainable mitigational approach against all these environmental odds? What hinders the Involvement of geologists to combat the environmental odds? Do we afford to allow a continuous deterioration of river morphology and the frequent occurrence of flood instead going for a river of training and reduce flood vulnerability? Should we go on sealing the tubewells yielding water contaminated with arsenic or other toxic elements and randomly install new wells for freshwater to aggravate the situation In stead of looking for a solution to prevent further contamination? How can we avoid landslides and prevent hazardous routes in making communication network in hilly terrains? What mechanism we should look for preventing salt-water intrusions while tapping Sou nd water from aquifers in e coastal region? what models we should follow in preventing from groundwater mining and land subsidence?

These are only few of the many environmental problems geology can answer for the solutions. It will not be unjust to say that if we want socio-economic emancipation, we must estab lish bridge between geology and other applied and engineering sciences

The writer is an Associate Professor, Department of Geology. University of Dhaka