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Searle, Mike; Cox, Jon

doi:10.1130/0016-7606(1999)111<0104:tsoaoo>2.3.co;2

Cited by 385 publications

(31 citation statements)

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“…Given its structural position below subducted units (oceanic and offscraped from the slab or as part of a forearc, i.e., the Seghin and Ashin units, respectively; Angiboust et al, 2016), it can be concluded that Siah Kuh was located outboard of Eurasia, as part of the lower plate with respect to the Eurasian subduction zone. The presence of boninites (Moghadam et al, 2013) suggests that the Siah Kuh seamount was also in a supra-subduction position with respect to a second, more southerly subduction (which is well documented by regional studies; e.g., Searle and Cox, 1999;Agard et al, 2006Agard et al, , 2007. Due to its structural position below the Ashin unit and the Seghin blueschists, the Siah Kuh unit most likely underwent subduction and metamorphism after them.…”

Section: Regional Significancementioning

confidence: 80%

Structure and metamorphism of a subducted seamount (Zagros suture, Southern Iran)

et al. 2019

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Millions of seamounts on modern and past seafloor end up being subducted, and only small pieces are recovered in suture zones. How they are metamorphosed and deformed is, however, critical to understand how seamount subduction can impact subduction zone geometry, fluid circulation or seismogenic conditions, and more generally to trace physical conditions along the subduction boundary. Since geophysical studies mostly reach the shallowest subducted seamounts and miss internal structures due to low resolution, there is a high need for fossil seamount exposures. We herein report on a fully exposed, 3D example of seamount that we discovered in the Siah Kuh massif, Southern Iran. Through a series of sections across the whole massif and the combination of magmatic-metamorphic-sedimentary petrological data, we document several distinct stages associated with seamount build-up on the seafloor and with subduction. In particular, we constrain different stages of metamorphism and associated mineralogy, with precise conditions for subduction-related metamorphism around 250 °C and 0.7 GPa, in the middle of the seismogenic zone. Extensive examination of the seismogenic potential of the Siah Kuh seamount reveals that it was not a large earthquake asperity (despite the report of a rare example of cm-scale, high-pressure pseudotachylyte in this study), and that it possibly behaved as a barrier to earthquake propagation. Finally, we discuss the nature of high-pressure fluid circulation preserved in this seamount.

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Section: Regional Significancementioning

confidence: 80%

Structure and metamorphism of a subducted seamount (Zagros suture, Southern Iran)

et al. 2019

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“…During the Late Cretaceous (ca. 95 Ma) an ophiolitic package of local geology formed through a sequence of fast oceanic spreading and supra-subduction zone volcanism within the Tethys Ocean, an ancient seaway that separated elements of Laurasia and Gondwana following the breakup of Pangea [12][13][14][15]. Geochronological, petrological, and structural evidence point towards this volcanism and creation of oceanic crust occurring within a geologically short period of a few million years or less [12][13][14][15][16].…”

Section: Study Areamentioning

confidence: 99%

“…The oceanic rocks that form this obducted package are collectively known as the Semail Ophiolite Complex (SOC). The SOC has been described as one of the best exposed and most complete ophiolitic assemblages in the world [13][14][15]17]. The geology at the Raki archaeological sites represents the uppermost levels of this SOC sequence ( Figure 2).…”

Section: Study Areamentioning

confidence: 99%

“…At least three VMS bodies are present at the Raki area: one at Raki 1, one at Tawi Raki, The geology at the Raki archaeological sites represents the uppermost levels of this SOC sequence ( Figure 2). Volcanic rocks range in composition from primarily basalt to basaltic andesite, and formed in direct contact or in close proximity to sea water near the paleo-ocean floor [14,18,19]; observable structures within this volcanic sequence, including pillowed surfaces and brecciated flows, are demonstrative of this formation environment [20,21]. Throughout the SOC, upper volcanic rocks have been classified into three to five separate units representing different stages of volcanic eruption across oceanic spreading center and supra-subduction zone environments [13,18,22].…”

Section: Study Areamentioning

confidence: 99%

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Detecting and Mapping Slag Heaps at Ancient Copper Production Sites in Oman

et al. 2019

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This study presents a new approach for detection and mapping of ancient slag heaps using 16-band multispectral satellite imagery. Understanding the distribution of slag (a byproduct of metal production) is of great importance for understanding how metallurgy shaped long-term economic and political change across the ancient Near East. This study presents results of slag mapping in Oman using WorldView-3 (WV3) satellite imagery. A semi-automated target detection routine using a mixed tuned matched filtering (MTMF) algorithm with scene-derived spectral signatures was applied to 16-band WV3 imagery. Associated field mapping at two copper production sites indicates that WorldView-3 satellite data can differentiate slag and background materials with a relatively high (>90%) overall accuracy. Although this method shows promise for future initiatives to discover and map slag deposits, difficulties in dark object spectral differentiation and underestimation of total slag coverage substantially limit its use. Resulting lower estimations of combined user’s (61%) and producer’s (45%) accuracies contextualize these limitations for slag specific classification. Accordingly, we describe potential approaches to address these challenges in future studies. As sites of ancient metallurgy in Oman are often located in areas of modern exploration and mining, detection and mapping of ancient slag heaps via satellite imagery can be helpful for discovery and monitoring of vulnerable cultural heritage sites.

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“…The Central Oman Mountains constitute an integral part of the continental Arabian plate (Searle and Cox 1999) and reveal a well bedded layer-cake platform carbonate succession (Aigner and Dott 1990;Koehrer et al 2012). The Jebel Akhdar (Fig.…”

Section: Location and Characteristics Of The Study Areamentioning

confidence: 99%

Ground-based hyperspectral imaging as a tool to identify different carbonate phases in natural cliffs

Beckert

Vandeginste

McKean

et al. 2018

International Journal of Remote Sensing

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Recent research has shown hyperspectral imaging to be a powerful tool to distinguish carbonate phases with slight compositional differences on quarry cliff faces. The traditional remote sensing setup uses an optimal short distance between the hyperspectral camera mounted on a tripod and a quarry wall characterized by a planar, mostly unweathered surface. Here we present results of a modified workflow geared to the application of ground-based hyperspectral imaging of rough and weathered cliff faces in order to map large scale dolomite bodies from a distance of up to several kilometres. The goal of the study was to determine unique spectral properties of fracture-controlled dolomite bodies in order to be able to distinguish them from a dolomitic host rock. In addition, the impact of weathering on carbonate phases and thus, the modification of the spectral signature between altered and unaltered carbonates is assessed. The spectral analysis is complemented by ICP-AES measurements of the spectrally measured powders. Furthermore, we examined the detection limits and characterisation potential of dolomite bodies from hyperspectral images captured at varying distances from cliff faces in the study area. Hyperspectral images of 10 natural cliffs distributed across the Central Oman Mountains were obtained with a Push broom scanner system. The high resolution of 5.45 nm (288 bands in total) enabled the visualization of small-scale changes in the near infrared continuous spectrum of all present lithofacies types. The determination of dolomite bodies of varying sizes (metre to hundreds of metres) on natural cliffs was achieved with the hyperspectral mapping approach and mapping results have been tested with the position of visually defined dolomite bodies on field panoramas. Spectra of natural cliffs contain a strong absorption peak indicative for iron which is absent in spectra of unweathered sample powders. However, ICP-AES analysis of powders revealed relatively low contents of iron of 12392 ppm. The strong peaks in field images are interpreted as linked to intensive weathering associated with the precepitation of goethite, hematite, specularite and manganese as well as intensive dedolomitization. Dedolomitization is indicated by calcitic spectra derived from the

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Cited by 385 publications

References 0 publications

Structure and metamorphism of a subducted seamount (Zagros suture, Southern Iran)

Structure and metamorphism of a subducted seamount (Zagros suture, Southern Iran)

Detecting and Mapping Slag Heaps at Ancient Copper Production Sites in Oman

Ground-based hyperspectral imaging as a tool to identify different carbonate phases in natural cliffs

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