Tethys Belt in the Anatolia-Caucasus-Black Sea Region: Basins, Magmatic Arcs, Ophiolites, and LIPs

2021 ◽  
Author(s):  
Vahid Teknik ◽  
Irina Artemieva ◽  
Hans Thybo
Keyword(s):  
Sedimentary Cover ◽  
Arabian Plate ◽  
Magnetic Data ◽  
Poor Correlation ◽  
Black Sea Region ◽  
Nw Iran ◽  
Magmatic Arc ◽  
Sedimentary Sequences ◽  
Mafic Intrusions ◽  
Lesser Caucasus

<p>We interpret the paleotectonic evolution and structure in the Tethyan belt by analyzing magnetic data sensitive to the presence of iron-rich minerals in oceanic fragments and mafic intrusions, hidden beneath sedimentary sequences or overprinted by younger tectono-magmatic events. By comparing the depth to magnetic basement (DMB) as a proxy for sedimentary thickness with average crustal magnetic susceptibility (ACMS), we conclude:</p><p> (1) Major ocean and platform basins have DMB >10 km. Trapped ocean relics may be present below Central Anatolian micro-basins with DMB at 6-8 km and high ACSM.  In intra-orogenic basins, we identify magmatic material within the sedimentary cover by significantly smaller DMB than depth to seismic basement.</p><p>(2) Known magmatic arcs (Pontides and Urima-Dokhtar) have high-intensity heterogeneous ACMS. We identify a 450 km-long buried (DMB >6 km) magmatic arc or trapped oceanic crust along the western margin of the Kirşehır massif from a strong ACMS anomaly. Large, partially buried magmatic bodies form the Caucasus LIP at the Transcaucasus and Lesser Caucasus and in NW Iran.</p><p>(3) Terranes of Gondwana affinity in the Arabian plate, S Anatolia and SW Iran have low-intensity homogenous ACMS.</p><p>(4) Local poor correlation between known ophiolites and ACMS anomalies indicate a small volume of presently magnetized material in the Tethyan ophiolites, which we explain by demagnetization during recent magmatism.</p><p>(5) ACMS anomalies are weak at tectonic boundaries and faults. However, the Cyprus subduction zone has a strong magnetic signature which extends ca. 500 km into the Arabian plate.</p>

Magmatic arcs, ophiolite belts and sedimentary basins in Anatolia interpreted from magnetic data

2020 ◽  
Author(s):  
Vahid Teknik ◽  
Hans Thybo ◽  
Irina Artemieva
Keyword(s):  
Black Sea ◽  
Sedimentary Basins ◽  
Arabian Plate ◽  
Magnetic Data ◽  
Western Anatolia ◽  
Magmatic Arc ◽  
Menderes Massif ◽  
Anatolian Plateau ◽  
Magnetic Basement ◽  
Ophiolite Emplacement

<p>Maps of depth to magnetic basement and crustal average susceptibility for the Anatolian plateau and adjacent regions are calculated by applying a spectral method to the magnetic data. The first map provides information on the shape of the sedimentary basins and the latter map is used for tracking magmatic arcs and ophiolite belts, which are covered by sediment and/or overprinted by different phases of magmatism and ophiolite emplacement. This is possible because magmatic and ophiolite rocks generally have the highest magnetic susceptibility values, and the huge contrast to sedimentary rocks makes magnetic data very useful.</p><p>The results shows a heterogeneous pattern associated with a mosaic of the many continental blocks, Tethyside sutures, magmatism and former subduction systems in Anatolia. Major basins such as northern part of the Arabian plateau, Black Sea basin, Mediterranean Sea basin and central Anatolian micro-basins are highlighted by very deep magnetic basement. Shallow magnetic basement is generally prominent in eastern Anatolia, and may represent that large amounts of magmatic rocks were emplacement during the convergence and compression of the Arabian plate, whereas a sporadic and asymmetric pattern of sedimentary basins in western Anatolia may have developed in the frame of the extensional regime. The average susceptibility map reveals extension of the Pontide magmatic arc in the north of Anatolia, following the coastline of the Black Sea. The average susceptibility indicates magmatism or ophiolite emplacement around the Kirşehır block. A 400 km long NW–SE elongated average susceptibility anomaly extends from south to NW of the Kirşehır beneath the Quaternary sediments, while the depth to magnetic basement indicate more than 6 km sediments. We speculate that this anomaly indicates a covered magnetic arc or a trapped part of oceanic crust. The westeward extension of the Urima-Dokhtar magmatic arc (UDMA) from the Iranian plateau fades away towards to Central Anatolian plateau. It suggest a geological boundary around the border between Iran and Turkey, which caused different magmatism between the two sides. A near zero magnetic anomaly in the Menderes massif region in the southwest of Turkey indirectly suggests a high geothermal gradient and hydrothermal activity that reduce the susceptibility of the rocks. This observation is in agreement with the crustal thinning and many geothermal fields of the Menderes massif.</p>

Lithostratigraphy of volcanic and sedimentary sequences in central Livingston Island, South Shetland Islands

1995 ◽  
Vol 7 (1) ◽  
pp. 99-113 ◽  
Author(s):  
J.L. Smellie ◽  
M. Liesa ◽  
J.A. Muñoz ◽  
F. Sàbat ◽  
R. Pallàs ◽  
...  
Keyword(s):  
Debris Flows ◽  
Lower Jurassic ◽  
South Shetland Islands ◽  
Polyphase Deformation ◽  
Magmatic Arc ◽  
Shetland Islands ◽  
Sedimentary Sequences ◽  
Early Mesozoic ◽  
Livingston Island ◽  
Volcaniclastic Rocks

Livingston Island contains several, distinctive sedimentary and volcanic sequences, which document the history and evolution of an important part of the South Shetland Islands magmatic arc. The turbiditic, late Palaeozoic–early Mesozoic Miers Bluff Formation (MBF) is divided into the Johnsons Dock and Napier Peak members, which may represent sedimentation in upper and lower mid-fan settings, respectively, prior to pre-late Jurassic polyphase deformation (dominated by open folding). The Moores Peak breccias are formed largely of coarse clasts reworked from the MBF. The breccias may be part of the MBF, a separate unit, or part of the Mount Bowles Formation. The structural position is similar to the terrigenous Lower Jurassic Botany Bay Group in the northern Antarctic Peninsula, but the precise stratigraphical relationships and age are unknown. The (?) Cretaceous Mount Bowles Formation is largely volcanic. Detritus in the volcaniclastic rocks was formed mainly during phreatomagmatic eruptions and redeposited by debris flows (lahars), whereas rare sandstone interbeds are arkosic and reflect a local provenance rooted in the MBF. The Pleistocene–Recent Inott Point Formation is dominated by multiple, basaltic tuff cone relicts in which distinctive vent and flank sequences are recognized. The geographical distribution of the Edinburgh Hill Formation is closely associated with faults, which may have been reactivated as dip-slip structures during Late Cenozoic extension (arc splitting).

Hydrocarbon Generative Properties and Maturity of Cretaceous and Eocene Sediments in the Middle Kura Depression, Azerbaijan

2021 ◽  
Author(s):  
Shahin Khosrov Akhundov ◽  
Mushfig Farhad Tagiyev ◽  
Arastun Ismail Khuduzade ◽  
Natig Namig Aliyev
Keyword(s):  
Organic Matter ◽  
Brown Coal ◽  
Lower Cretaceous ◽  
Vitrinite Reflectance ◽  
Sedimentary Cover ◽  
Hard Coal ◽  
Marine Origin ◽  
Formation Conditions ◽  
Lesser Caucasus ◽  
Reflectance Data

Abstract Meso-Cenozoic sedimentary cover in the Middle Kura depression located between the Greater and Lesser Caucasus mountain structures contains numerous oil accumulations. According to studies in the Cretaceous and Paleogene strata, sedimentary organic matter is of mixed clastic-marine origin. Moderate amounts of organic matter have been recorded in the Eocene sediments (on average 0.70%), in the Upper and Lower Cretaceous average values made up 0.39% и 0.42%, respectively. Analysis of bitumoid composition suggests that in a number of areas bitumoids have experienced a widespread movement across the sedimentary strata. The results of measurements on isolated samples indicate that the Cretaceous strata have only advanced to the initial hard-coal stage of organic transformation (0.48-0.55%Ro). On vitrinite reflectance data the Eocene deposits in studied areas of the Middle Kura depression have reached initial (brown-coal) stage of catagenetic transformation (±0.48Ro%; est. paleotemperature of 85°C). Nonetheless, analysis of formation conditions of commercial HC accumulations found earlier in the Eocene strata allows considering them the most prospective in the Middle Kura depression.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

scholarly journals Tectonic influence on axial-transverse sediment routing in the Denver Basin

2022 ◽  
Author(s):  
Glenn R. Sharman ◽  
Daniel F. Stockli ◽  
Peter Flaig ◽  
Robert G. Raynolds ◽  
Marieke Dechesne ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Detrital Zircon ◽  
Foreland Basin ◽  
The Other ◽  
Front Range ◽  
Denver Basin ◽  
Dispersal Patterns ◽  
Magmatic Arc ◽  
Sedimentary Sequences ◽  
Basin Fill

ABSTRACT Detrital zircon U-Pb and (U-Th)/He ages from latest Cretaceous–Eocene strata of the Denver Basin provide novel insights into evolving sediment sourcing, recycling, and dispersal patterns during deposition in an intracontinental foreland basin. In total, 2464 U-Pb and 78 (U-Th)/He analyses of detrital zircons from 21 sandstone samples are presented from outcrop and drill core in the proximal and distal portions of the Denver Basin. Upper Cretaceous samples that predate uplift of the southern Front Range during the Laramide orogeny (Pierre Shale, Fox Hills Sandstone, and Laramie Formation) contain prominent Late Cretaceous (84–77 Ma), Jurassic (169–163 Ma), and Proterozoic (1.69–1.68 Ga) U-Pb ages, along with less abundant Paleozoic through Archean zircon grain ages. These grain ages are consistent with sources in the western U.S. Cordillera, including the Mesozoic Cordilleran magmatic arc and Yavapai-Mazatzal basement, with lesser contributions of Grenville and Appalachian zircon recycled from older sedimentary sequences. Mesozoic zircon (U-Th)/He ages confirm Cordilleran sources and/or recycling from the Sevier orogenic hinterland. Five of the 11 samples from syn-Laramide basin fill (latest Cretaceous–Paleocene D1 Sequence) and all five samples from the overlying Eocene D2 Sequence are dominated by 1.1–1.05 Ga zircon ages that are interpreted to reflect local derivation from the ca. 1.1 Ga Pikes Peak batholith. Corresponding late Mesoproterozoic to early Neoproterozoic zircon (U-Th)/He ages are consistent with local sourcing from the southern Front Range that underwent limited Mesozoic–Cenozoic unroofing. The other six samples from the D1 Sequence yielded detrital zircon U-Pb ages similar to pre-Laramide units, with major U-Pb age peaks at ca. 1.7 and 1.4 Ga but lacking the 1.1 Ga age peak found in the other syn-Laramide samples. One of these samples yielded abundant Mesozoic and Paleozoic (U-Th)/He ages, including prominent Early and Late Cretaceous peaks. We propose that fill of the Denver Basin represents the interplay between locally derived sediment delivered by transverse drainages that emanated from the southern Front Range and a previously unrecognized, possibly extraregional, axial-fluvial system. Transverse alluvial-fluvial fans, preserved in proximal basin fill, record progressive unroofing of southern Front Range basement during D1 and D2 Sequence deposition. Deposits of the upper and lower D1 Sequence across the basin were derived from these fans that emanated from the southern Front Range. However, the finer-grained, middle portion of the D1 Sequence that spans the Cretaceous-Paleogene boundary was deposited by both transverse (proximal basin fill) and axial (distal basin fill) fluvial systems that exhibit contrasting provenance signatures. Although both tectonic and climatic controls likely influenced the stratigraphic development of the Denver Basin, the migration of locally derived fans toward and then away from the thrust front suggests that uplift of the southern Front Range may have peaked at approximately the Cretaceous-Paleogene boundary.

scholarly journals Ore Formation During Jurassic Subduction of the Tethys Along the Eurasian Margin: Constraints from the Kapan District, Lesser Caucasus, Southern Armenia

2019 ◽  
Vol 114 (7) ◽  
pp. 1251-1284 ◽  
Author(s):  
Johannes Mederer ◽  
Robert Moritz ◽  
Massimo Chiaradia ◽  
Richard Spikings ◽  
Jorge E. Spangenberg ◽  
...  
Keyword(s):  
Middle Jurassic ◽  
Late Jurassic ◽  
Ore Deposits ◽  
Sulfide Deposit ◽  
Short Time Interval ◽  
Ore Formation ◽  
Magmatic Arc ◽  
Argillic Alteration ◽  
Lesser Caucasus ◽  
Host Rocks

Abstract The Kapan mining district in the southernmost Lesser Caucasus is one of the few locations along the central Tethyan metallogenic belt where ore-forming processes were associated with magmatic arc growth during Jurassic Tethys subduction along the Eurasian margin. Three ore deposits of the Kapan district were investigated in this study: Centralni West, Centralni East, and Shahumyan. The ore deposits are hosted by Middle Jurassic andesitic to dacitic volcanic and volcaniclastic rocks of tholeiitic to transitional affinities below a late Oxfordian unconformity, which is covered by calc-alkaline to transitional Late Jurassic-Early Cretaceous volcanic rocks interlayered with sedimentary rocks. The mineralization consists of veins, subsidiary stockwork, and partial matrix replacement of breccia host rocks, with chalcopyrite, pyrite, tennantite-tetrahedrite, sphalerite, and galena as the main ore minerals. Centralni West is a dominantly Cu deposit, and its host rocks are altered to chlorite, carbonate, epidote, and sericite. At Centralni East, Au is associated with Cu, and the Shahumyan deposit is enriched in Pb and Zn as well as precious metals. Both deposits contain high-sulfidation mineral assemblages with enargite and luzonite. Dickite, sericite, and diaspore prevail in altered host rocks in the Centralni East deposit. At the Shahumyan deposit, phyllic to argillic alteration with sericite, quartz, pyrite, and dickite is dominant with polymetallic veins, and advanced argillic alteration with quartz-alunite ± kaolinite and dickite is locally developed. The lead isotope composition of sulfides and alunite (206Pb/204Pb = 18.17–18.32, 207Pb/204Pb = 15.57–15.61, 208Pb/204Pb = 38.17–38.41) indicates a common metal source for the three deposits and suggests that metals were derived from magmatic fluids that were exsolved upon crystallization of Middle Jurassic intrusive rocks or leached from Middle Jurassic country rocks. The δ18O values of hydrothermal quartz (8.3–16.4‰) and the δ34S values of sulfides (2.0–6.5‰) reveal a dominantly magmatic source at all three deposits. Combined oxygen, carbon, and strontium isotope compositions of hydrothermal calcite (δ18O = 7.7–15.4‰, δ13C = −3.4−+0.7‰, 87Sr/86Sr = 0.70537–0.70586) support mixing of magmatic-derived fluids with seawater during the last stages of ore formation at Shahumyan and Centralni West. 40Ar/39Ar dating of hydrothermal muscovite at Centralni West and of magmatic-hydrothermal alunite at Shahumyan yield, respectively, a robust plateau age of 161.78 ± 0.79 Ma and a disturbed plateau age of 156.14 ± 0.79 Ma. Re-Os dating of pyrite from the Centralni East deposit yields an isochron age of 144.7 ± 4.2 Ma and a weighted average age of the model dates of 146.2 ± 3.4 Ma, which are younger than the age of the immediate host rocks. Two different models are offered, depending on the reliability attributed to the disturbed 40Ar/39Ar alunite age and the young Re-Os age. The preferred interpretation is that the Centralni West Cu deposit is a volcanogenic massive sulfide deposit and the Shahumyan and Centralni East deposits are parts of porphyryepithermal systems, with the three deposits being broadly coeval or formed within a short time interval in a nascent magmatic arc setting, before the late Oxfordian. Alternatively, but less likely, the three deposits could represent different mineralization styles successively emplaced during evolution and growth of a magmatic arc during a longer time frame between the Middle and Late Jurassic.

Miocene structural inversion of the Adjara-Trialeti back-arc basin as a far-field effect of the Arabia-Eurasia collision

2021 ◽  
Author(s):  
Thomas Gusmeo ◽  
William Cavazza ◽  
Victor Alania ◽  
Onise Enukidze ◽  
Massimiliano Zattin ◽  
...  
Keyword(s):  
Late Miocene ◽  
Field Effect ◽  
Stress Transfer ◽  
Normal Faults ◽  
Far Field ◽  
Magmatic Arc ◽  
Late Middle Miocene ◽  
Structural Inversion ◽  
Lesser Caucasus ◽  
Back Arc

<p>Young back-arc rift basins, because of the not yet dissipated extensional thermal signature, can be easily inverted following changes in the geodynamic regime and/or far-field stress transmission. Structural inversion of such basins mainly develops through reactivation of normal faults, particularly if the latter are favourably oriented with respect to the direction of stress transfer. The Adjara-Trialeti fold-and-thrust belt of SW Georgia is an example of this mechanism, resulting from the structural inversion of a continental back-arc rift basin developed on the upper plate of the northern Neotethys slab in Paleogene times, behind the Pontides-Lesser Caucasus magmatic arc. New low-temperature thermochronological data [apatite fission-track (AFT) and (U-Th)/He (AHe) analyses] were obtained from a number of samples, collected across the Adjara-Trialeti belt from the former sedimentary fill of the basin and from syn-rift plutons. AFT central ages range between 46 and 15 Ma, while AHe ages cluster mainly between 10 and 3 Ma. Thermal modelling, integrating AFT and AHe data with independent geological constraints (e.g. depositional/intrusion age, other geochronological data, thermal maturity indicators and stratigraphic relationships), clearly indicates that the Adjara-Trialeti back-arc basin was inverted starting from the late Middle Miocene, at 14-10 Ma. This result is corroborated by many independent geological evidences, found for example in the adjacent Rioni, Kartli and Kura foreland basins and in the eastern Black Sea offshore, which all suggest a Middle-Late Miocene phase of deformation linked with the Adjara-Trialeti FTB building. Adjara-Trialeti structural inversion can be associated with the widespread Middle-to-Late Miocene phase of shortening and exhumation that is recognised from the eastern Pontides to the Lesser Caucasus, the Talysh and the Alborz ranges. This tectonic phase can in turn be interpreted as a far-field effect of the Arabia-Eurasia collision, developed along the Bitlis suture hundreds of kilometres to the south.</p>

Integration of induced polarization, resistivity, and magnetic data of IOA occurrences in Ararenda, western of the Santa Quiteria magmatic arc, Ceará Brazil

2021 ◽  
pp. 103624
Author(s):  
Cristian Dikson Araujo da Silva ◽  
Clóvis Vaz Parente ◽  
Rodoilton Stevanato ◽  
Rafael Espíndola Canata ◽  
Karen M. Leopoldino Oliveira
Keyword(s):  
Induced Polarization ◽  
Magnetic Data ◽  
Magmatic Arc

The Geodynamic Evolution of Iran

2021 ◽  
Vol 49 (1) ◽  
pp. 9-36
Author(s):  
Robert J. Stern ◽  
Hadi Shafaii Moghadam ◽  
Mortaza Pirouz ◽  
Walter Mooney
Keyword(s):  
Subduction Zone ◽  
Full Range ◽  
Accretionary Prism ◽  
Arabian Plate ◽  
Earthquake Hazards ◽  
Northern Margin ◽  
Magmatic Arc ◽  
Early Stages ◽  
Plate Margin ◽  
Convergent Plate Margin

Iran is a remarkable geoscientific laboratory where the full range of processes that form and modify the continental crust can be studied. Iran's crustal nucleus formed as a magmatic arc above an S-dipping subduction zone on the northern margin of Gondwana 600–500 Ma. This nucleus rifted and drifted north to be accreted to SW Eurasia ∼250 Ma. A new, N-dipping subduction zone formed ∼100 Ma along ∼3,000 km of the SW Eurasian margin, including Iran's southern flank; this is when most of Iran's many ophiolites formed. Iran evolved as an extensional continental arc in Paleogene time (66–23 Ma) and began colliding with Arabia ∼25 Ma. Today, Iran is an example of a convergent plate margin in the early stages of continent-continent collision, with a waning magmatic arc behind (north of) a large and growing accretionary prism, the Zagros Fold-and-Thrust Belt. Iran's crustal evolution resulted in both significant economic resources and earthquake hazards. ▪  Iran is a natural laboratory for studying how convergent plate margins form, evolve, and behave during the early stages of continental collision. ▪  Iran formed in the past 600 million years, originating on the northern flank of Gondwana, rifting away, and accreting to SW Eurasia. ▪  Iran is actively deforming as a result of collision with the Arabian plate, but earthquakes do not outline the position of the subducting slab. ▪  The Cenozoic evolution of Iran preserves the main elements of a convergent plate margin, including foredeep (trench), accretionary prism, and magmatic arc.

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