Friday, February 17, 2012
Türkiye Jeolojisinin 'Babası' : İhsan Ketin (ikinci kısım)
Yer Bilimleri ile ilgilenen insanların hemen hemen hepsinin eline İhsan Ketin’in yazdığı bir Genel Jeoloji kitabı geçmiştir diye düşünüyorum. Sevgili Celal Şengör’ün bıkmadan usanmadan zikrettiği bu ismin onuruna hazırlanmış olan “Tectonic Evolution of the Tethyan Region” kitabının takdiminde Ketin'in hayatının kısa bir özeti yazılmış. Ben de bu özetin net ortamında da olmasını ister oldum ve kitabın başındaki takdimi buraya aktardım. Tetis okyanusunun evrimi ile ilgili Nato tarafından finansmanı sağlanan bir projeden çıkan kitabın içerdiği bilgiler şu an için geçerli olan modellere kaynak niteliğini koruyor. Kitabın editörlüğünü İhsan Ketin’in ekibinden A.M.C. Şengör ile Yücel Yılmaz, Aral Okay, Naci Görür (aka:baba) gerçekleştirmiş. Takdimin içinde bazı kısımların anlaşılmamasına karşın linkler de ekledim, vaktiniz varsa sevgili İhsan Ketin'i tanımak adına okuyabilirsiniz. :::
The organizers and participants of the NATO Advanced Study Institute “Tectonic Evolution of the Tethyan Region” wish to dedicate this Institute and its published proceedings to Dr.rer.nat. İhsan Ketin, emeritus professor of geology in the Istanbul Technical University in grateful recognition of his important contributors to our understanding of the geological structure and evolution of the central part of the Alpine-Himalayan mountain ranges. In doing so we also wish to underline that the influence of Ketin’s work has long overflowed the boundaries of the Alpine-Himalayan system an made a conspicuous impact on theoretical tectonics in general. His discovery in 1948 of the North Anatolian strike-slip fault and with it the west-drift of a rigid Anatolian block with respect to its surroundings not only was an important step in the recognition of the widespread occurrence of large strike-slip faults in the world, but it also constitutes one of the earliest papers in which the tectonics of a large area was interpreted in terms of relative horizontal motion of a few internally rigid blocks along narrow zones of displacement. His discovery in 1956 of the late Cretaceous-early Cainozoic age of the central Anatolian crystalline axis disposed of Kober’s theory of symmetric orogens with ancient median masses along the axis of symmetry in one of its type localities. Instead , Ketin showed in 1959 that Asia minor as a whole was an asymmetric south vergent orogen whose construction lasted through several episodes of mountain-building from the late Palaezoic to the present. This view formed the main basis for the most plate tectonic interpretations of Turkey in the last two decades.
İhsan Ketin was born on 10th of April in the ancient central Anatolian town of Kayseri(Caesarea), located at the foot of the mighty volcano of Erciyes (Mt. Aergus) as a subject of Sultan Mehmet V. Şn that eventful year of 1914. The family, of which Ketin was the second child, was of modest means. His father, Ali Efendi, was compelled to spend much of time during which Ketin grew up as a child, fighting for his country: first through World War I and then 1922, in Mustafa Kemal’s War of Liberation. During this time Ketin came under two powerful influences that eventually determined the course of his life: The first was that of his maternal grandmother Hatice Hanım, a strong-willed Anatolian woman who instilled in Ketin the desire to do something worthwhile. The second source of influence was mute, but possibly more powerful: the towering Mt.Erciyes awakened in Ketin a love of nature, especially of her mineral kingdom that eventually became the child’s life-long occupation.
Before Ketin completed the first decade of his life the Ottoman Empire had become history and the new Republic of Turkey had been declared with Mustafa Kemal as its first president. This extraordinary man was determined to transform the old Ottoman society into a new Turkish nation and was aware that education was his most effective weapon. He sent hordes of young men to various western European countries to receive a university education with the instruction to come back “to raise Turkey to the higher level of contemporary civilisation”
When Ketin boarded the train to go to Berlin in 1932 his heart was filled with the inspiration that radiated from Mustafa Kemal to learn the science of the west and to bring it back to his homeland, where Ketin hoped, it could take root and flourish. But the Berlin Ketin arrived at was the troubled capital of the Weimar Republic, the artificial child of the Versailles Treaty, which was about to expire in the bloody hands of the architect of the infamous Third Reich, Adolf Hitler. The raging inflation, cancerous unemployment, rampant terrorism and the resulting misery induced the quiet natured Anatolian youth after his first semester in the university to move away from Berlin, where he had been exposed to the ideas of Hans Stille at his lectures.
From the Prussian capital Ketin moved to the sphere of influence of another giant of tectonics in Bonn. Hans Closs, the holder of the chair in geology in Bonn and at the same time the influential editor-in-chief of the Geologische Rundschau became not only Ketin’s teacher and eventual doctoral adviser, but also his close, almost fatherly friend. Between 1935-1938 Ketin remained under Closs tutelage that imparted on him a zeal for careful field observation, especially geologic mapping, and a larger reservoir of knowledge along with a humanism that contrasted sharply with the prevailing racism of the Nazi Germany, but that found a warm echo in Ketin’s upbringing that had taken place in the heartland of the Ottoman Empire, in which numerous ethnic groups had peacefully coexisted for centuries. Ketin ended his studies with a doctoral dissertation on the tectonics and volcanism of the region around Bad Bertrich, which was published in 1940.
Following the completion of his formal studies in Germany, Ketin returned to Turkey in the Autumn of 1938 and was appointed assistant professor at the Institute of Geology of the University of İstanbul, where during World War I, the noted German geomorphologist and structural geologist Walther Penck had been the head of the Institute. When Ketin arrived in İstanbul, he found himself the third Turkish citizen with a PhD in geology! The first, a certain Anastase Georgiades from Istanbul had obtained his doctorate from Zurich in 1918, but evidently had not returned to Turkey. The second, Dr. Ahmet Can Okay was an immigrant from the Soviet Central Asia and had come to Turkey after he had completed his studies in Germany. Thus Ketin was the first native of Turkey to work in his country with a Ph D in geology.
When Ketin joined the Faculty of the Institute of Geology in Istanbul, Professor Hamit Nafiz Pamir, the one-time assistant and interpreter to Walther Pecnk was the head of the Institute. A graduate of the University of Geneva, Pamir had had to interrupt his doctoral studies owing to World War I. Since then, he had been compelled to spend more time organizing the earth sciences in the newly founded Republic of Turkey than doing research. Therefore, when Ketin returned to his country he found that no research tradition existed in geology. One had to be created and it is perhaps Ketin’s greatest achievement that during the course of his professional life his work became in Turkey the cornerstone of a research tradition in geology.
Ketin’s initial activity in Turkey was split between research and teaching. His first research projects naturally reflected the strong influence of Cloos and Ketin plunged energitically into mapping granites and brittle structures.
A year after Ketin’s arrival in İstanbul, a long-dormant zone of earthquakes in northern Turkey, the structure that Ketin was to make popular throughout the world under the designation of the North Anatolian Faul resumed its activity with the disastrous Erzincan quake of 29th December, 1939 that took the lives of more than 30000 inhabitans. Between 1940 and 1948 Ketin devoted a number of mainly descriptive papers to te earthquakes that progressed westwards from Erzincan.
Finally, in 1948 Ketin published his classic paper “Über die tektonisch-mechanischen Folgerungen aus den grossen anatolischen Erdbeben des letzten Dezennium” ( On the tectonic-mechanic implications of the great Anatolian earthquakes of the last decade). In this paper he documented that the earthquakes in northern Turkey had all occurred along an east-west fault zone that had the character of a right-lateral strike-slip fault. Ketin noticed that with one exception, all of the recent earthquakes had taken place along this fault zone, while vast areas of the Anatolian highland remained aseismic. Ketin deduced from this that an “Anatolian Block”, composed of the aseismic areas was “drifting westwards” with respect to the areas to the north.
Ketin also noted that one earthquake had occured near Kozan near the northeastern corner of the Eastern Mediterranean. This, he speculated, may be the expression of another fault that perhaps delimits the “Anatolian Block” against the Arabian platform. This prediction was vindicated only 23 years later when the Bingöl earthquake of 22nd May, 1971 took place on what was to be called the East Anatolian Fault, the left-lateral conjugate pair of the North Anatolian Fault.
Ketin’s 1948 paper was the second, after W.Q.Kennedy’s 1946 paper on the Great Glen Fault, of a series of papers that led to the recognation of the widespread presence and importance of large, in many places orogen-parallel, strike-slip faults, a recognation for which plate tectonics was to supply the rationale nearly a quarter of a century later.
In the meantime Ketin also spent all his summers mapping in diverse parts of his previously only sparsely mapped country. Although he initially had to map on a scale of 1:100000, his maps were immaculate: I remember going to the field in Bursa with Ketin in 1984, with his 1946 manuscript map in our hands. We were in an ophiolitic melange terrain and nearly 40 years ago Ketin had carefully mapped the larger blocks! The result of one of these summerly mapping exercises served as his “Habilitation Thesis” and Ketin was promoted to associate professorship in 1945, three years later he had married a young teacher of geography Miss Bedia Alpün.
In 1953 Ketin moved to the then newly founded Faculty of Mines of the old Istanbul Technical University. Here Ketin continued his studies both on the neo- and palaeotectonics of Turkey. In the interval 1953-1956 he was particularly concerned with testing hypothesis of Sir Edward Bailey and J.W.McCallien, then of the University of Ankara. Bailey and McCallien had discovered an extensive outcrop of an ophitolitic melange to the immediate southeast of Ankara and assumed that it underlay the Kırşehir Massif, interpreted as a giant klippe of northerly origin. Ketin’s mapping showed that this was not the case and the Massif in reality underlay the ophiolites. He further showed that the Massif itself had formed only in the late Cretaceous, contrary to the prevailing view of a much older (Palaeozoic or even Precambrian) age. Ketin thus demonstrated that the northern marginal ranges of Turkey, called Pontides after the Pontus Euxinus (Black Sea), were older than the Kırşehir Massif, whereas the southern marginal chains, the Taurides (after the Taurus of the classical geographers), in which sedimentary successions reach from the Cambrian to the Eocene (in places even Miocene) without a major angular unconformity, were clearly younger. This implied that Turkey had grown from north to south during much of the Phanerozoic, a recognition that clashed with the then-fashionable two-sided orogen model of Kober and Stille, according to which the Pontides represented the north-vergent north flank, while the Taurides were the south-vergent south flank of a symmetric Anatolian orogen with the crystalline massifs of Menderes and Kırşehir forming the axial Zwischengebirge. When Ketin presented some of his conclusions in 1955 at the “Geotectonics Symposium” held in honour of Stille in Hannover, the old and dogmatic German master told Ketin that he found this story to hard to believe. Although Ketin had submitted a manuscript intended for the proceedings of the symposium, his paper was somehow left out of the final Festschrift. He later published different versions in Turkey and in Austria and those papers formed the basis of our modern views of the palaeotectonic evolution of Turkey.
In 1959 Ketin published his first palaeotectonic synthesis of Turkey. This paper represents a clear break from the Kober-Stille model and a kind of return to Suess’s original view of 1909, that portreyed Turkey as a south-vergent outer arc of his Asiatic structure (Asiatischer Bau). Here Ketin showed that orogenic deformation during the Phanerozoic generally migrated from north to south in Turkey. On the basis of the age of the final orogeny and the palaeogeographic development, Ketin distinguished four major tectono-stratigrapihc zones three of which extended west to east along the entire lenght of the country. Only the fourth, the southernmost unit, was confined to the southeastern extremity of the country, being located on the Arabian Platform. Ketin’s zones were the following, from north so south:
1- Pontides ( Palaeozoic and Mesozoic orogenic deformation)
2- Anatolides (Mesozoic and Cainoic orogenic deformation)
3- Taurides (early Cainozoic orogenic deformation)
4- Border Folds (late Cainozoic orogenic deformation)
In 1961 and 1966 Ketin further refined this classification, which for many years, until the advent of the theory of plate tectonics, served as the basis for all paleotectonic studies in Turkey. When Şengör (1979) and Şengör and Yılmaz (1981) synthesized the tectonic evolution of Turkey from the viewpoint of plate tectonics, all they had to do was to give different names to the same units that Ketin had distinguished more than two decades earlier. Thus, the Pontides became the Pontide island arc (to be split into a Rhodope-Pontide arc and a Sakarya arc in 1981), the Anatolides and the Taurides were united into and Anatolide/Tauride platform (from which Şengör et al., 1982, separated a Kırşehir block as an independent unit), and the Border Folds remained the same (in 1979 Ozan Sungurlu suggested to rename them as the Assyrides to maintain paralellism with the other units’ names).
Since the publication of these landmark papers Ketin maintained his activity both in palaeo- and in neotectonics. His fieldwork largely was the basis for the concept of the East Anatolian Accretionary Complex (perhaps most fundamental modification introduced into his 1966 classification), for the discovery of the Palaeo-Tethyan suture in Turkey, and for the classification of the neotectonic units of Turkey.
In addition to his research activity in Turkey, Ketin also stands out as an earth-science teacher and an organizer of the earth sciences in the country. As a teacher he not only insturacted myriads of students, but also is the author of the most widely used text-books of physical geology, structural geology and geology of Turkey in this country. His lecture notes on such diverse topics as the recent developments in the earth sciences and the tectonics of Africa are monuments to conciseness and clarity. Ketin is an enthusiastic field geologist and his enthusiasm contagious. To this day he delights in introducing students into their first mapping area, in acquainting them “with the language of the rocks” as he is fond of saying, in demonstrating for them how to record their observations in minute detail and showing them how to sketch outcrops and panaromas! Ketin was the one who established the İ.T.Ü. tradition that every post-graduate geology student has to prepare at least one detailed geological map as a part of his or her thesis work. In addition to his formal teaching duties, Ketin has been also the foremost popularizer of the earth sciences in Turkey. Amidst his multifarious duties he has found time always to write popular articles for the general education of the public.
Ketin’s organizational skills are best displayed by his ability to form and direct research groups. Today his group is the most active and internationally best-known in this country. As a department head, Ketin has always made sure that even the youngest member of his team became an independent researcher. He has repeatedly stressed throughout his career that he expected his students and associates to improve what had been done earlier. More than once he exclaimed: “ Don’t come to me to tell me that i was right. Come to me if you found that i had been wrong!”
Ketin was once the president of the Geological Society of Turkey and twice the Dean of Faculty of Mines of the İ.T.Ü. For many years he was a panel member of the Turkish National Research Council for Research and Technology. He also represented Turkey on many international scientific committees and was the Turkish contributor of the International Tectonic Map of Europe.
Ketin’s activity as a scientist, university teacher and scientific organize found the highest recognition both in Turkey and abroad. In 1981 he became the first recipient of the Hamit Nafiz Pamir medal of Geological Society of Turkey. In the same year the TUBİTAK gave his the Science Award for the totality of his works, the highest recognition for a scientist in Turkey. Ketin was elected as Honorary Fellow of the Geological Society of London in 1984 and of the Geological Society of America in 1988. Also in 1988 he reciived the prestigeous Gustav-Steinmann-Medaille of the Geologische Vereinigung in the federal Republic of Germany for his “far-sighted geotectonic work, contributions to the geology of Turkey and to international co-operation in the earth sciences”.
I here speak in the name of the organizers, the contributors, and the participants of the İhsan Ketin Advanced Study Institute on the Tectonic Evolution of the Tethyan Region in wishing Proffessor Ketin a long, healthy, and productive life. ""