Lithostratigraphy of the Upper Triassic–Middle Jurassic Shemshak Group of Northern Iran

2009 ◽  
Vol 312 (1) ◽  
pp. 129-160 ◽  
Author(s):  
Franz Theodor Fürsich ◽  
Markus Wilmsen ◽  
Kazem Seyed-Emami ◽  
Mahmoud Reza Majidifard
Keyword(s):  
Middle Jurassic ◽  
Upper Triassic ◽  
Northern Iran

scholarly journals Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

2011 ◽  
Vol 149 (1) ◽  
pp. 19-38 ◽  
Author(s):  
ALI SHEKARIFARD ◽  
FRANÇOIS BAUDIN ◽  
KAZEM SEYED-EMAMI ◽  
JOHANN SCHNYDER ◽  
FATIMA LAGGOUN-DEFARGE ◽  
...  
Keyword(s):  
Middle Jurassic ◽  
Vitrinite Reflectance ◽  
Upper Triassic ◽  
Petroleum Exploration ◽  
Thermal Maturity ◽  
Northern Iran ◽  
Carbonaceous Shales ◽  
Petroleum Generation ◽  
Central Eastern ◽  
Alborz Range

AbstractOrganic petrography and geochemical analyses have been carried out on shales, carbonaceous shales and coals of the Shemshak Group (Upper Triassic–Middle Jurassic) from 15 localities along the Alborz Range of Northern Iran. Thermal maturity of organic matter (OM) has been investigated using vitrinite reflectance, Rock-Eval pyrolysis and elemental analysis of kerogen. Reflectance of autochthonous vitrinite varies from 0.6 to 2.2% indicating thermally early-mature to over-mature OM in the Shemshak Group, in agreement with other maturity parameters used. The shales of the Shemshak Group are characterized by poor to high residual organic carbon contents (0.13 to 5.84%) and the presence of hydrogen-depleted OM, predominantly as a consequence of oxidation of OM at the time of deposition and the hydrogen loss during petroleum generation. According to light-reflected microscopy results, vitrinite/vitrinite-like macerals are dominant in the kerogen concentrates from the shaly facies. The coals and carbonaceous shales of the Shemshak Group show a wide range in organic carbon concentration (3.5 to 88.6%) and composition (inertinite- and vitrinite-rich types), and thereby different petroleum potentials. Thermal modelling results suggest that low to moderate palaeo-heat flow, ranging from 47 to 79 mW m−2 (57 mW m−2 on average), affected the Central-Eastern Alborz basin during Tertiary time, the time of maximum burial of the Shemshak Group. The maximum temperature that induced OM maturation of the Shemshak Group seems to be related to its deep burial rather than to a very strong heat flow related to an uppermost Triassic–Liassic rifting. The interval of petroleum generation in the most deeply buried part of the Shemshak Group (i.e. Tazareh section) corresponds to Middle Jurassic–Early Cretaceous times. Exhumation of the Alborz Range during Late Neogene time, especially along the axis of the Central-Eastern Alborz, where maximum vitrinite reflectance values are recorded, probably destroyed possible petroleum accumulations. However, on the northern flank of the Central-Eastern Alborz, preservation of petroleum accumulations may be expected. The northern part of the basin therefore seems the best target for petroleum exploration.

Characterization of organic matter in the fine-grained siliciclastic sediments of the Shemshak Group (Upper Triassic–Middle Jurassic) in the Alborz Range, Northern Iran

2009 ◽  
Vol 312 (1) ◽  
pp. 161-174 ◽  
Author(s):  
Ali Shekarifard ◽  
François Baudin ◽  
Johann Schnyder ◽  
Kazem Seyed-Emami
Keyword(s):  
Organic Matter ◽  
Middle Jurassic ◽  
Upper Triassic ◽  
Northern Iran ◽  
Fine Grained ◽  
Alborz Range ◽  
Siliciclastic Sediments

scholarly journals Geochemistry of siliciclastic rocks from the Shemshak Group (Upper Triassic–Middle Jurassic), northeastern Alborz, northern Iran: implications for palaeoweathering, provenance, and tectonic setting

2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Azizollah TAHERI ◽  
Mahdi JAFARZADEH ◽  
John S. ARMSTRONG-ALTRIN ◽  
Seyed Reza MIRBAGHERI
Keyword(s):  
Middle Jurassic ◽  
Tectonic Setting ◽  
Upper Triassic ◽  
Northern Iran ◽  
Siliciclastic Rocks

scholarly journals Age and microfacies of oceanic Upper Triassic radiolarite components from the Middle Jurassic ophiolitic mélange in the Zlatibor Mountains (Inner Dinarides, Serbia) and their provenance

2017 ◽  
Vol 68 (4) ◽  
pp. 350-365 ◽  
Author(s):  
Hans-Jürgen Gawlick ◽  
Nevenka Djerić ◽  
Sigrid Missoni ◽  
Nikita Yu. Bragin ◽  
Richard Lein ◽  
...  
Keyword(s):  
Continental Slope ◽  
Oceanic Crust ◽  
Middle Jurassic ◽  
Sedimentary Cover ◽  
Upper Triassic ◽  
Late Triassic ◽  
Ophiolitic Mélange ◽  
Reef Limestone ◽  
Sedimentary Succession ◽  
Unit Yield

AbstractOceanic radiolarite components from the Middle Jurassic ophiolitic mélange between Trnava and Rožanstvo in the Zlatibor Mountains (Dinaridic Ophiolite Belt) west of the Drina–Ivanjica unit yield Late Triassic radiolarian ages. The microfacies characteristics of the radiolarites show pure ribbon radiolarites without crinoids or thin-shelled bivalves. Beside their age and the preservation of the radiolarians this points to a deposition of the radiolarites on top of the oceanic crust of the Neo-Tethys, which started to open in the Late Anisian. South of the study area the ophiolitic mélange (Gostilje–Ljubiš–Visoka–Radoševo mélange) contains a mixture of blocks of 1) oceanic crust, 2) Middle and Upper Triassic ribbon radiolarites, and 3) open marine limestones from the continental slope. On the basis of this composition we can conclude that the Upper Triassic radiolarite clasts derive either from 1) the younger parts of the sedimentary succession above the oceanic crust near the continental slope or, more convincingly 2) the sedimentary cover of ophiolites in a higher nappe position, because Upper Triassic ribbon radiolarites are only expected in more distal oceanic areas. The ophiolitic mélange in the study area overlies different carbonate blocks of an underlying carbonate-clastic mélange (Sirogojno mélange). We date and describe three localities with different Upper Triassic radiolarite clasts in a mélange, which occurs A) on top of Upper Triassic fore-reef to reefal limestones (Dachstein reef), B) between an Upper Triassic reefal limestone block and a Lower Carnian reef limestone (Wetterstein reef), and C) in fissures of an Upper Triassic lagoonal to back-reef limestone (Dachstein lagoon). The sedimentary features point to a sedimentary and not to a tectonic emplacement of the ophiolitic mélange (= sedimentary mélange) filling the rough topography of the topmost carbonate-clastic mélange below. The block spectrum of the underlying and slightly older carbonate-clastic mélange points to a deposition of the sedimentary ophiolitic mélange east of or on top of the Drina–Ivanjica unit.

Middle Jurassic organic-walled dinoflagellate cysts and palynofacies from Telma-Dareh, south of Sari, northern Iran

2015 ◽  
Vol 223 ◽  
pp. 128-137 ◽  
Author(s):  
Petr Skupien ◽  
Ján Pavluš ◽  
Mostafa Falahatgar ◽  
Mojtaba Javidan
Keyword(s):  
Middle Jurassic ◽  
Dinoflagellate Cysts ◽  
Northern Iran

Geology of the Cadwallader Group and the Intermontane–Insular superterrane boundary, southwestern British Columbia

1987 ◽  
Vol 24 (11) ◽  
pp. 2279-2291 ◽  
Author(s):  
Margaret E. Rusmore
Keyword(s):  
British Columbia ◽  
Middle Jurassic ◽  
Tectonic Evolution ◽  
Middle Triassic ◽  
Upper Triassic ◽  
Tectonic Block ◽  
Volcanic Arc ◽  
Arc Volcanism ◽  
Clastic Rocks ◽  
Tectonic Settings

Several lower Mesozoic, fault-bounded units separate the Intermontane and Insular superterranes in southwestern British Columbia. Detailed study of one of these Mesozoic units, the Cadwallader Group, helps clarify the boundary between the superterranes and establish the tectonic evolution of southwestern British Columbia. The Cadwallader Group is the oldest unit in an Upper Triassic through Middle Jurassic volcanic and sedimentary tectono-stratigraphic terrane. Two formations, the Pioneer and the Hurley, compose the Cadwallader Group; the previously recognized Noel Formation is no longer considered valid. The Pioneer Formation contains pillow basalt, flows, and basalt breccia. Siltstone, sandstone, conglomerate, and minor amounts of limestone megabreccia and basalt belonging to the Hurley Formation conformably overlie the Pioneer. The Hurley spans latest Carnian or earliest Norian to middle Norian time. Two episodes of deformation affected the Cadwallader, and a thrust fault separates the group from slightly younger clastic rocks of the Tyaughton Group. Similarities in clastic rocks indicate the Tyaughton was deposited on the Cadwallader; together the units form the Cadwallader terrane. Basalts and clastic rocks in the terrane record deposition in or near a Carnian to earliest Norian volcanic arc. Volcanism waned later in the Norian, but presence of the arc is preserved in the clastic rocks.Oceanic rocks of the Middle Triassic to Middle Jurassic Bridge River terrane became juxtaposed with the Cadwallader terrane in Middle Jurassic time, after which the terranes functioned as a single tectonic block. Contrasting volcanic histories suggest that the Cadwallader terrane was not accreted to the Intermontane superterrane until Middle Jurassic or Early Cretaceous time, although the similar tectonic settings of Stikinia and the Cadwallader terrane allow a common earlier history. The Cadwallader terrane is not part of either the Alexander terrane or Wrangellia, and so the inboard margin of the Insular superterrane must lie west of the Cadwallader terrane.

New data on the geology of the Lozovoe zone (Upper Triassic–Middle Jurassic) of the Crimean Mountains

2015 ◽  
Vol 70 (5) ◽  
pp. 386-398 ◽  
Author(s):  
A. N. Stafeev ◽  
T. V. Sukhanova ◽  
I. V. Latysheva ◽  
V. L. Kosorukov ◽  
Yu. I. Rostovtseva ◽  
...  
Keyword(s):  
Middle Jurassic ◽  
Upper Triassic ◽  
Crimean Mountains
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