29 research outputs found
Une revue de la répartition et de l’extension des glaciations pléistocènes et des glaciers actuels en Turquie
Les glaciers actuels et les dépôts glaciaires d’âge pléistocène occupent trois régions en Turquie : 1. La chaîne du Taurus : Les deux tiers des glaciers actuels en Turquie sont concentrés dans la partie sud-est de cette chaîne. Le mont Cilo (4 135 m) supporte, à lui seul, plus de dix glaciers. Dans la partie centrale, de petits glaciers actuels sont observés sur les massifs de Aladağ (3 756 m) et de Bolkardağ (3 524 m) ; 2. La chaîne des Pontides : Sur le plus haut sommet de cette chaîne (mont Kaçkar, 3 932 m) cinq glaciers se sont développés. Bien que plusieurs montagnes contiennent des vallées glaciaires, les conditions climatiques actuellement très humides ont grandement modifié les dépôts morainiques ; 3. Les volcans et les massifs montagneux du plateau anatolien : Le mont Ararat (5 165 m), avec une calotte de glace de 10 km2, le mont Süphan (4 058 m) et le mont Erciyes (3 917 m) contiennent des glaciers actifs. Plusieurs autres montagnes dans le plateau anatolien portent également des traces de leur passé glaciaire. Dans l’ensemble, peu de données sont disponibles sur les glaciers turcs et les études les plus récentes mentionnent un recul des glaciers au moins depuis le début du XXe siècle.Present day glaciers and Quaternary glacial deposits occur in 3 regions in Turkey: 1. The Taurus Mountain Range: Two thirds of the present day Turkish glaciers are concentrated in the SE part of this range. Mount Cilo (4 135 m) alone supports more than ten glaciers. In the Central part, Aladağ (3 756 m) and Bolkardağ (3 524 m) constitute two of the most important mountains where small glaciers are present. 2. The Pontic Mountain Range: On the Mount Kaçkar (3 932 m) five glaciers are developed. Although several other mountains contain glacial valleys in the chain, most of the glacier related landforms are severely altered because of the actual humid climatic conditions. 3. Volcanoes and independent mountains of the Anatolian Plateau: Volcanoes such as Mount Ararat (5 165 m) supports an ice cap of 10 km2. The Mount Süphan (4 058 m) and Mount Erciyes (3 917 m) also show signs of glacial activity and active glaciers. Several other mountains in Central Anatolia also bear traces of past glacial activity. As a whole, very limited data are available on Turkish glaciers, and recent observations indicate a glacier recession at least since from the beginning of the 20th century.Türkiye’deki güncel buzulların ve Kuvaterner buzullaşmasına ait izlerin gözlemlendiği bölgeler başlıca 3 gurup altında toplanırlar : 1. Toros Dağları : Türkiye’nin Güncel buzulların üçte ikisi GD Anadolu’da toplanmıştır. Bunlardan sadece Cilo Dağı (4 135 m) 10’dan fazla buzul barındırır. Orta Toroslar’da, Aladağ (3 756 m) ve Bolkardağ’da (3 524 m) çok küçük de olsa birkaç buzul bulunmaktadır. 2. Doğu Karadeniz Dağları : Bölgenin en yüksek zirvesi Kaçkar (3 932 m) olup toplam 5 adet buzul bulunmaktadır. Bölgenin çeşitli yerlerinde önemli buzul vadileri gözlenmesine rağmen, günümüzün nemli iklim koşulları nedeniyle buzullar ile ilgili yerşekillerinin büyük çoğunluğu yoğun bir aşınıma maruz kalmışlardır. 3. Volkanlar ve Anadolu’nun diğer dağları : Türkiye’nin en büyük volkanı olan Ağrı Dağı (5 165 m) ülkenin yegane buz takkesini (10 km2) barındırır. Süphan (4 058 m) ve Erciyes (3 917 m) volkanlarında da küçük de olsa güncel buzullar mevcuttur. Bunun yanı sıra Anadolu’nun çeşitli dağlarında da Kuvaterner buzullaşmasına ait izlere rastlamak mümkündür. Türkiye’nin çeşitli dağlarında Kuvaterner buzullaşmasının izleri net bir şekilde gözlenmekle beraber, buzul evrelerinin mutlak yaşlandırılması henüz yapılmamıştır. Buna rağmen 20. yy’ın başından beri yapılan gözlemler güncel buzulların çekilmekte olduklarını ortaya koymaktadır
Last Glacial Maximum and Younger Dryas piedmont glaciations in Blidinje, the Dinaric Mountains (Bosnia and Herzegovina):insights from 36Cl cosmogenic dating
Volcanism and evolution of the landscapes in Cappadocia
Cappadocia, situated in the Central Anatolia Plateau in Turkey, is characterized by widespread volcanic rocks (lavas, ignimbrites and pyroclastic deposits) alternating with fluvio-lacustrine sediments of Miocene (around 10 million years) to Quaternary age. The evolution of the Cappadocian landscape starts with gently sloping plateaus, which are then dissected, usually along fractures of soft-unwelded ignimbrites, to form mushroom-like, cone-shaped structures known locally as ‘fairy chimneys’. We present here a brief description of the stratigraphy of the Cappadocian volcanic succession and explain types of volcanic products. Different landforms created by the erosion of the volcanic rocks are also explained. Because of the favorable engineering properties of the ignimbrites, ancient populations have carved their houses, churches and even underground cities for centuries. Today, this unique cultural and morphological heritage site, classified under UNESCO World Heritage List since 1985, is one of the most visited regions of Turkey
Quaternary uplift rates of the Central Anatolian Plateau, Turkey: insights from cosmogenic isochron-burial nuclide dating of the Kızılırmak River terraces
The Central Anatolian Plateau (CAP) in Turkey is a relatively small plateau (300 × 400 km) with moderate average elevations of ∼1 km situated between the Pontide and Tauride orogenic mountain belts. Kızılırmak, which is the longest river (1355 km) within the borders of Turkey, flows within the CAP and slowly incises into lacustrine and volcaniclastic units before finally reaching the Black Sea. We dated the Cappadocia section of the Kızılırmak terraces in the CAP by using cosmogenic burial and isochron-burial dating methods with 10Be and 26Al as their absolute dating can provide insight into long-term incision rates, uplift and climatic changes. Terraces at 13, 20, 75 and 100 m above the current river indicate an average incision rate of 0.051 ± 0.01 mm/yr (51 ± 1 m/Ma) since ∼1.9 Ma. Using the base of a basalt fill above the modern course of the Kızılırmak, we also calculated 0.05–0.06 mm/yr mean incision and hence rock uplift rate for the last 2 Ma. Although this rate might be underestimated due to normal faulting along the valley sides, it perfectly matches our results obtained from the Kızılırmak terraces. Although up to 5–10 times slower, the Quaternary uplift of the CAP is closely related to the uplift of the northern and southern plateau margins respectively
La Cappadoce méridionale de la Préhistoire à l'époque byzantine
Il y a environ 25 ans, Olivier Pelon organisait à l’Institut Français d’Études Anatoliennes d’Istanbul un colloque destiné à faire l’état des recherches sur la Cappadoce méridionale jusqu’à la fin de l’époque romaine. Un quart de siècle après ce premier colloque, il était intéressant de faire un nouveau point sur l’avancée des recherches dans cette Cappadoce méridionale, de la préhistoire à la période byzantine. Ce nouveau colloque, placé cette fois encore sous l’égide de l’Institut Français d’Études Anatoliennes et intégré à la série des Rencontres d’archéologie de l’IFEA réunit vingt-trois communications. Si les périodes néolithique et chalcolithique ont été particulièrement bien représentées, ce qui témoigne bien de l’importance de cette phase de la préhistoire cappadocienne, liée aux gisements d’obsidienne des Melendiz Dağları, on soulignera en revanche l’absence presque totale du Bronze Ancien. Cette phase est en effet peu représentée dans l’archéologie locale. La même remarque peut s’appliquer au Bronze Moyen. La fin du Bronze Moyen, fort heureusement, est représentée à Porsuk, de même que le Bronze Récent qui bénéficie, depuis peu, tout comme l’Âge du Fer, du démarrage fructueux des fouilles de Kınık Höyük. Enfin, l’Antiquité tardive et Byzance ont pu être représentées, principalement autour de Tyane, ce qui n’avait pas pu être le cas lors du premier colloque. En octobre 2012, quelques semaines avant la tenue de la Rencontre, on apprenait malheureusement le décès brutal et inattendu d’Olivier Pelon, ancien directeur de la mission de Porsuk (jusqu’en 2002) et organisateur de ce premier colloque cappadocien. C’est bien en hommage à sa mémoire que notre Rencontre cappadocienne de 2012 et sa publication ont été naturellement dédiées
Quaternary uplift rates of the Central Anatolian Plateau, Turkey: insights from cosmogenic isochron-burial nuclide dating of the Kızılırmak River terraces
The Central Anatolian Plateau (CAP) in Turkey is a relatively small plateau (300 × 400 km) with moderate average elevations of ∼1 km situated between the Pontide and Tauride orogenic mountain belts. Kızılırmak, which is the longest river (1355 km) within the borders of Turkey, flows within the CAP and slowly incises into lacustrine and volcaniclastic units before finally reaching the Black Sea. We dated the Cappadocia section of the Kızılırmak terraces in the CAP by using cosmogenic burial and isochron-burial dating methods with 10Be and 26Al as their absolute dating can provide insight into long-term incision rates, uplift and climatic changes. Terraces at 13, 20, 75 and 100 m above the current river indicate an average incision rate of 0.051 ± 0.01 mm/yr (51 ± 1 m/Ma) since ∼1.9 Ma. Using the base of a basalt fill above the modern course of the Kızılırmak, we also calculated 0.05–0.06 mm/yr mean incision and hence rock uplift rate for the last 2 Ma. Although this rate might be underestimated due to normal faulting along the valley sides, it perfectly matches our results obtained from the Kızılırmak terraces. Although up to 5–10 times slower, the Quaternary uplift of the CAP is closely related to the uplift of the northern and southern plateau margins respectively
ZARA GÜNEYİ (SiVAS HAVZASI) KARASAL-SIĞ DENİZEL MİYOSEN ÇÖKELLERİNİN LİTOSTRATİGRAFİSİ VE FASİYES ÖZELLİKLERİ
Sivas Miyosen havzası
birimlerinin zaman ve mekân içerisindeki ortamsal ve sedimanter özellikleri ile
çökel evrimlerini belirlemek amacı ile Zara güneyinde yapılan detay çalışmalar
sonucunda Erken Miyosen yaşlı Ağılkaya formasyonunun (1900 m), Karayün üyesi
(alüviyal yelpaze ve akarsu çökelleri), Hafik üyesi (sabka jipsleri),
Karacaören üyesi (sığ denizel çökeller) ile Erken-Orta Miyosen yaşlı Eğribucak
formasyonunun (550 m), Sekitarla üyesi (akarsu çökelleri), olmak üzere 2
formasyon ve 4 üye ayırtlanmıştır. Bu birimler 13 litofasiyes tanımlanarak
incelenmiştir. Anılan bu fasiyesler sığ denizel-lagün, gel-git ortamı,
playa-sabka, alüviyal yelpaze ve akarsu ortamlarının değişik litolojilerini
içerirler. Sivas havzasında geniş yayılım sunan ve yaşı tartışma konusu olan
Hafik jipsleri, havzanın farklı kesimlerindeki gözlemlere dayanılarak, bu
çalışmada (?)Oligosen - Alt Miyosen olarak kabul edilmiştir. Paleoakıntı
değerlerinin Kuzey-Kuzeybatı yönünde yoğunlaşmış olması ve petrografik veriler,
havzayı dolduran kırıntılı istifin, muhtemelen Güney-Güneydoğudaki bir
ofiyolitik temelden beslendiğini göstermektedir
Intraspecific Length Variation and Shell Thickness of the Ostracod <i>Cyprideis torosa</i> (Jones, 1850) as a Potential Tool for Palaeosalinity Characterization
Cyprideis torosa (Jones) is a common ostracod species in brackish waters of large parts of the world. The species appears in, but it is not restricted to, marginal marine areas, and it thus plays a significant role in identifying variable impacts between the marine and terrestrial realms as its carapace changes phenotypically under various conditions. This variability could be a highly valuable source of information in palaeoecology. We use valves of this species living in different lagoonal and lacustrine environments of the Kızılırmak Delta at the Turkish Black Sea coast since the Mid-Holocene. By measuring the valve sizes of adult individuals and A-1 instars and documenting the thickness classes of the adult shells we found a good positive correlation between the size of female valves and the prevailing salinity (correlation coefficient: 0.56), while such a correlation is lacking for ontogenetic stage A-1. No changes of the height/length ratio of the valves were recognizable along the salinity gradient. Shells are significantly thicker under relatively stable, higher saline conditions, but thinner in highly variable and low saline deltaic lakes. Both morphological features, size and shell thickness of C. torosa (Cyprideis torosa), are thus potential tools to give palaeo-environmental information, especially in C. torosa-dominated, low diversity marginal marine environments