Age determination and evolution of the paleoenvironmental conditions of Oligocene-Miocene sediments (Qom Formation) in the Qom Back-Arc Basin (northern margin of Neotethys), Central Iran

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Amrollah Safari ◽  
Hossein Ghanbarloo ◽  
Mahdiyeh Mahyad
Keyword(s):  
Age Determination ◽  
Central Iran ◽  
Northern Margin ◽  
Qom Formation ◽  
Back Arc

Carbonate Sequence Stratigraphy of a Back-Arc Basin: A Case Study of the Qom Formation in the Kashan Area, Central Iran

2007 ◽  
Vol 81 (3) ◽  
pp. 488-500 ◽  
Author(s):  
XU Guoqiang ◽  
ZHANG Shaonan ◽  
LI Zhongdong ◽  
SONG Lailiang ◽  
LIU Huimin
Keyword(s):  
Sequence Stratigraphy ◽  
Central Iran ◽  
Qom Formation ◽  
Carbonate Sequence ◽  
Back Arc

scholarly journals Middle Givetian to late Famennian (Middle to Late Devonian) conodonts from the northern margin of Gondwana (Kerman region, Central Iran)

2020 ◽  
pp. 1-19
Author(s):  
Fatane Zamani ◽  
Mehdi Yazdi ◽  
Ali Bahrami ◽  
Catherine Girard ◽  
Claudia Spalletta ◽  
...  
Keyword(s):  
Central Iran ◽  
Late Devonian ◽  
Northern Margin

Composition, structure and tectonic analysis of the Shangrimuce arc-continent collision zone on the northern margin of the Central Qilian, NW China

2021 ◽  
Author(s):  
Hongyuan Zhang ◽  
Zhibin Lei ◽  
Bo Yang ◽  
Qing Liu ◽  
Haijun Zhang ◽  
...  
Keyword(s):  
Shear Zones ◽  
Oceanic Lithosphere ◽  
Late Ordovician ◽  
Island Arc ◽  
Qilian Mountain ◽  
Northern Margin ◽  
Early Ordovician ◽  
Collision Zone ◽  
Two Stages ◽  
Back Arc

<p>A 1:50000 regional survey, covering an area of about 2000 km<sup>2</sup>, was carried out in the Shangrimuce area of Qilian Mountain in Northwest China. The results show that during Caledonian, the northern margin of the Central Qilian block experienced collision with mature island arcs and subsequently northward expansion. In the Shangrimuce study area, five geological units have been identified; they are, form south to north, back-arc basin, early Ordovician island arc, inter arc basin, middle Late Ordovician island arc, and fore-arc and oceanic lithosphere amalgamation zone. </p><p>(1) back-arc basin. In the Yangyuchi- Shule River- Cuorigang- Wawusi area, there may be a back-arc spreading basin, and there should be spreading basins in this area. It is speculated that there was a northward reverse subduction in the late Ordovician, accompanied by a syenite body, a broad spectrum dyke swarms and an accretionary wedge zone in the whole area.</p><p>(2) early Ordovician island arc. In the Shangrimuce-Dander area, the Proterozoic basement granitic gneiss, the early Ordovician island arc block and the high-pressure geological body all occur in the form of thrust horses, forming a double metamorphic belt, which reveals the existence of ocean subduction to south in the early Ordovician. </p><p>(3) inter arc basin. On both banks of Tuolai River to the east of Yanglong Township, there are early Middle Ordovician inter-arc basins with oceanic crust. </p><p>(4) middle Late Ordovician island arc. To the north of Tuolai River, there is a middle Late Ordovician island arc belt. Both sides of the island arc zone experienced strong ductile shear deformation, which recorded a complex arc-continent collision. </p><p>(5) fore-arc and oceanic lithosphere amalgamation zone (Fig.1). The Yushigou area has developed a fore-arc and oceanic lithospheric amalgamation zone, with weakly deformed fore-arc flysch basin, strongly deformed siliceous rocks, pillow Basalt, diabase, gabbro, peridotite and other rock assemblages.</p><p>Combined with the characteristics of arc-continent collision zone in the Western Pacific, there are two stages of shear zone series (Fig.2). One is ductile shear zones formed by the South dipping gneissic belt, revealing the existence of oceanic subduction accretion wedge and emplacement of high-pressure rocks. Another superimposed one is north dipping. This indicates that the arc-continent collision caused by back-arc reverse subduction, which ultimately controls the overall geometric and kinematic characteristics of the shear zones in the region.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gepj.8219836ca50067454890161/sdaolpUECMynit/12UGE&app=m&a=0&c=40b3389c641f2d0ca723e1527c32927e&ct=x&pn=gepj.elif&d=1" alt=""></p><p>Figure 1 United sections showing a Caledonian trench-arc system in the Qilian Mountain, NW China.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gepj.8def566da50066084890161/sdaolpUECMynit/12UGE&app=m&a=0&c=e82258ecc235c4e618abd6c035b58232&ct=x&pn=gepj.elif&d=1" alt=""></p><p>Figure 2 Structural analysis at Hongyahuo, indicating two stages of deformation.</p><p>The research has been supported by projects from the Ministry of Land and Resources (No.201211024-04; 1212011121188) and the 2020 undergraduate class construction project from China University of Geosciences (Beijing) (No. HHSKE202003).</p><p> </p>

Middle Devonian (Givetian) conodonts from the northern margin of Gondwana (Soh and Natanz regions, north-west Isfahan, Central Iran): biostratigraphy and palaeoenvironmental implications

2015 ◽  
Vol 95 (4) ◽  
pp. 555-577 ◽  
Author(s):  
Ali Bahrami ◽  
Peter Königshof ◽  
Iliana Boncheva ◽  
Mahbobeh Sadat Tabatabaei ◽  
Mehdi Yazdi ◽  
...  
Keyword(s):  
Middle Devonian ◽  
Central Iran ◽  
Northern Margin ◽  
North West

scholarly journals Review of the Ordovician stratigraphy and fauna of the Anarak Region in Central Iran

2015 ◽  
Vol 65 (4) ◽  
pp. 403-435 ◽  
Author(s):  
Leonid E. Popov ◽  
Vachik Hairapetian ◽  
David H. Evans ◽  
Mansoureh Ghobadi Pour ◽  
Lars E. Holmer ◽  
...  
Keyword(s):  
North China ◽  
Cold Water ◽  
Central Iran ◽  
Metamorphic Complex ◽  
North African ◽  
Northern Margin ◽  
Faunal Assemblages ◽  
Lower Ordovician ◽  
Low Diversity ◽  
Sedimentary Succession

Abstract The Ordovician sedimentary succession of the Pol-e Khavand area, situated on the northern margin of the Yazd block, has important differences from those in other parts of Central Iran. It has been established that the presumably terminal Cambrian to Lower Ordovician volcano-sedimentary Polekhavand Formation, exposed in the Pol-e Khavand area, has non-conformable contact with greenschists of the Doshakh Metamorphic Complex. The succeeding, mainly siliciclastic Chahgonbad Formation contains low to moderately diverse faunal assemblages, including brachiopods, cephalopods, trilobites and tentaculitids. The Darriwilian age of the lower part of the formation is well established by the co-occurrence of brachiopod genera Camerella, Phragmorthis, Tritoechia and Yangtzeella. The associated rich cephalopod fauna is different from the Darriwilian cephalopod associations of the Alborz terrane and may show some affinity with warm water faunas of North China and South Korea. It is likely that the Mid Ordovician fauna recovered from the lower part of the Chahgonbad Formation settled in the area sometime during a warming episode in the late Darriwilian. By contrast the low diversity mid Katian brachiopod association includes only three taxa, which occur together with the trilobite Vietnamia cf. teichmulleri and abundant, but poorly preserved tentaculitids questionably assigned to the genus Costatulites. This faunal association bears clear signatures linking it to the contemporaneous cold water faunas of the Arabian, Mediterranean and North African segments of Gondwana. Four brachiopod species recovered from the Chahgonbad Formation, including Hibernodonta lakhensis, Hindella prima, Lomatorthis? multilamellosa and Yangtzeella chupananica are new to science.

Back-Arc Paleo-Tethys Related Blueschist from Central Iran, South of Chupanan, Isfahan Province

2013 ◽  
Vol 21 (4) ◽  
pp. 433-447
Author(s):  
Ghodrat Torabi ◽  
Shoji Arai
Keyword(s):  
Central Iran ◽  
Isfahan Province ◽  
Back Arc
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