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This year rain in many parts of Jordan was very abundant. While this is usually a most welcomed event in the semi arid regions of Jordan, especially after several years of below average precipitation, this proved to be catastrophic for Petra. Monument 609 fell due to the heavy rain. It is a beautiful facade which was classified by Brunowe and von Damazewski as Proto Hegr type. Others have classified it in their own scheme of typology as Double Cornice Phase II, Hellenistic or Cavetto type. After a short field trip, I was able to find the photo for the monument in my database dating back to 1996. The reason for the field trip was that the monument has changed so much over the years that a recent photo (after the facade slid off its supporting background rock) could only be matched to the older photo after the visit. By comparing other nearby features in our database with their modern pictures an exact match was found. What one sees from the pictures is that in 1996 the colour of the facade was dark due to a protective patina. Often a hard material deposits on the surface of rocks thus giving them some sort of protection. However this so called desert varnish or patina is not safe from the natural weathering process that threatens stone. The recent photo shows that severe weathering of the facde has occured since 1996. True to the old wisdom, the facade has beautiful layered colours of red and white formed by a chromatographic process that is responsible for the formation of Leisgang rings. In sandstones this is a process in which differential deposition of coloured rings of minerals leads to very beautiful ring shaped colours of red, white, green and blue (depending on the minerals pesent in the rock),  often in contour like formations. The trouble is that this a symptom of serious damage. Normally the beutifully coloured sandstone can be scratched into powder and rubbed off with your finger.

Now what has happened to monument 609. A close examination of the sandstone that forms the backbone rock shows that in an area where the red sandstone type (Precambrian) predominates, there is an unusual deposit of white Ordovician Sandstone within the matrix of the rock. It so happens that the white vein or deposit lies parallel to the surface of the facade and forms an interface between two layers of the red type. In our earlier studies and confirmed by those of Fitzner and Heinrichs form the Aachen Geologic Institute (http://www.stone.rwth-aachen.de/download.htm ), Ordovician sandstone is more porous (about 14%) than Precambrian (about 10%). This sudden variation in properties creates a weak spot or region, highly susceptible to weathering. To make matters worse another vein of white sandstone lies at 90 degrees to the first one and cuts through the facade itself. Over the years water action with the salts that it always carries, not only has affected the surface of the facade and changing its colour, but has hit the white vein deposit in a very drastic matter. While this was not observed from the front of the monument and was hidden from an observer in front of the facade it has been taking hold over many years. During winter time rain  dissolves salts that naturally occur in nature and carries them into the pores of the rock. It also dissolves the cementing minerals that give the rock its structural strength.  In the dry season the water evaporates at the surface depositing salts that due to their expansion break the cementing agents. As the surface water evaporates more of the water in the deeper of pores of the rock migrate to the surface and dries of with the same detrimental surface deposition of salts. The results in this case is that the patina has been weathered and the beautiful colours appear. A more important effect of this wetting-drying process is that the white veins are weakened (weathered) at a faster rate than the bulk of the backbone rock. Over the years the process has weakened bit by bit those veins. During the wet cycle the material expands. In summer the material contracts as it dries. This breaks further the cementing material of the rock. When heavy rain came after  several year of drought, the veins got so much of a shock (dissolution of salts and cementing minerals as well as material expansion due to the wetting process) could no longer carry the heavy weight of the facade (I estimate roughly 500 tons of mass) and the monument slid down to the ground suddenly but smoothly. at the interface the rock was crushed into a fine flowery powder. In other spots the rock was torn apart and sheared by the falling mass. The facade while falling also broke into two main pieces. This happened exactly where the 90 degrees vein lies and the white surface where the two parts split, a testimony to the role of inhomogeneous materials in this serious event. The massive facade fell on a camel (poor thing), that was left to shelter from the rain by its owner, and killed instantly.

Lessons learnt:  Accidents like this are threatening to monumnts and to life. The facade lies in an area that is rarely visited by tourists and park managers. It lies out of the way from the tracks normally taken by humans. Only a few Bedouins probably haunt the area. While it was possible to detect problems for the monument form the changes in the surface appearance of the facade, there was no way to predict that the facade was endangered or to anticipate when catastrophe was going to occur. Weathering is not just a surface phenomenon. It occurs deep inside the rock and such techniques that only look at the surfaces of facades might prove useless in risk assessment and risk management. The shear size of the site and its complex weathering profiles makes any monitoring and intervention steps a very demanding and costly operation. Once more my database and its GIS system has proved itself very useful in identifying the monument that has been destroyed and has brought to light possible problems that need serious attention and must been addressed as soon as possible. Ms Tahani Salih from the Petra Arcaheological Park was the first person to identify the number of the monument. Nevrtheless, the field visit I made together with the data in the database confirmed unequivocally the identification.

On the Database and GIS System for Petra

Well, after an extensive field campaign lot of new monuments (features) have been recorded. Most of these are generally neglected by tourists, archaeologists and researchers. They are not as magnificent as the Treasury, Palace Tomb, Al Deir,  Obelisk Tomb or Corinthean Tomb and many of the scores of fabulous facades that we all admire. However some of these features are simply charming. look at the first horse relief images above. A rider may have been effaced by weathering. Some also think may be there is the profile of another horse’s head with its rider. One image may be showing the head of a slain gazelle. were they hunting? I leave it to your imagination. Some lovely niches were also recorded recently. We have recorded the geographic positions so that they are ready to be added to our AIS (Archaeological Geographic Information System).

More importantly there are many features that are eroding rapidly in neglect. Some hint at a magnificent facade that is no longer there. Some are buried so that only the top is showing. Who knows what archaeologists might find underneath. The documentation process continues and will provide researchers with an important tool. Keeping the memory of monuments that are in neglect and may disappear is one of the main purposes of this effort. The only problem is that the more we look the more features we find. It seems like a never ending process. One of these days we hope to say all is done.

“We shall not cease from exploration

And the end of all our exploring

Will be to arrive at where we started

And know the place for the first time

Through the unknown, unremembered gate

When the last of earth left to discover

Is that which was the beginning”

From LITTLE GIDDING (No. 4 of ‘Four Quartets’) by T.S. Eliot

Exactly how I feel when I visit Petra. Every time I go around a corner I’ve never been to, I find something new or learn something different. Even when I go with people who have never been, I see the wonder and awe, a first visit is guaranteed to bestow. I see a totally different and new perspective through the eyes of every new visitor, and I know the place for the first time.

Science continues to explore and often goes over old facts and findings to discover something new: Something that others have missed before. Physicists continue to discover new subatomic particles, but they have yet to grasp the ultimate truth. Quantum Physics continues to seek the ultimate theory that explains all phenomena, regardless of the size of the object and the type and extent of the forces to which it is subjected to.. That is the beauty of Science and that is the bedazzling challenge.

Archaeology is no different in this respect. There are lot of gaps in our knowledge about the past. Often guess work and many assumptions have to be made. Modern advancements in Science and Technology have have placed in our hands excellent tools for deciphering the past. Even till now when research revisits sites and historic objects, new facts and new hypothesis emerge, and we know the “place” for the first time.

A pressing question comes to mind. Why this fascination with the past? Is Archaeology just a ”Curiosity Science” or just another field of learning? The truth is that Man is concerned about his short stay on earth. Compared to History his lifetime is like a drop in an ocean, much less significant, if compared to the Universe. How can man achieve eternity? Apart from the religious view of eternity, physical eternity is something that is in the realm of wishful thinking. Even religious people, fear of death and the unknown after life is another reason for the hope to extend life for as longas possible. Individual physical eternity is impossible. Thus we find satisfaction in “eternity” as a species.  We also like to keep our memory as alive as possible long after we are gone. In the past we find our roots and memory of the past is something we value. The past suddenly becomes of utmost importance. Some believe that history repeats itself, and that in itself is justification enough for our deeply rooted interest in it. More importantly, we seek to learn more about our roots and how we became what we are now. From the present’s perspective the past gains more and more significance. Projected into the future, the past and its understanding become only part of our yearning for eternity. The physical eternity on Earth (as opposed to the religious etermity) that we can achieve is the continued survival of the species. The present soon becomes past, the future present, and all three are intertwined. We must continue to exist for as long as we can. As a result not only do we need to  study the past but we must attempt to conserve and preserve the signs it has left us. We would like to freeze any evidence of past human activities both in space and time. If we are so keen on learning about the past and if we are fascinated by what our forefathers have left to us, no matter how scant, or how affected by the ravges of time, then surely it is our duty to pass our inheritance to future generations. They too should be able sense, celebrate,  and revel in the species’ eternity.

My concern about the conservation of the Cultural Heritage comes from the belief that it is the species duty to maintain the links with the past and to understand it as a means to better our future.