Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: a case study for  the COSC-1 borehole, Sweden

Abstract. Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply eroded orogens like the Scandinavian Caledonides allow us to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications of a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can constrain the origin of this reflectivity. To this end, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. For some intervals of the COSC-1 borehole, the core and downhole velocities deviate by up to 2 km s−1. These differences in the core and downhole velocities are most likely the result of microcracks mainly due to depressurization. However, the core and downhole velocities of the intervals with mafic rocks are generally in close agreement. Seismic anisotropy measured in laboratory samples increases from about 5 % to 26 % at depth, correlating with a transition from gneissic to schistose foliation. Thus, metamorphic foliation has a clear expression in seismic anisotropy. These results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.

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Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden

10.5194/egusphere-egu2020-13955 ◽

2020 ◽

Author(s):

Felix Kästner ◽

Simona Pierdominici ◽

Judith Elger ◽

Christian Berndt ◽

Alba Zappone ◽

...

Keyword(s):

Seismic Anisotropy ◽

Seismic Velocity ◽

Metamorphic Rocks ◽

Seismic Velocities ◽

Mafic Rocks ◽

Seismic Properties ◽

The Core ◽

Nappe Complex ◽

Thrust Zone ◽

Mountain Belts

Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply-eroded orogens like the Scandinavian Caledonides allow to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications for a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can help to constrain the origin of this reflectivity. In this study, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. The core and downhole velocities deviate by up to 2 km/s. However, velocities of mafic rocks are generally in close agreement. Seismic anisotropy increases from about 5 to 26 % at depth, indicating a transition from gneissic to schistose foliation. Differences in the core and downhole velocities are most likely the result of microcracks due to depressurization of the cores. Thus, seismic velocity can help to identify mafic rocks on different scales whereas the velocity signature of other lithologies is obscured in core-derived velocities. Metamorphic foliation on the other hand has a clear expression in seismic anisotropy. To further constrain the effects of mineral composition, microstructure and deformation on the measured seismic anisotropy, we conducted additional microscopic investigations on selected core samples. These analyses using electron-based microscopy and X-ray powder diffractometry indicate that the anisotropy is strongest for mica schists followed by amphibole-rich units. This also emphasizes that seismic velocity and anisotropy are of complementary importance to better distinguish the present lithological units. Our results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.

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Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden

10.5194/se-2019-161 ◽

2019 ◽

Author(s):

Felix Kästner ◽

Simona Pierdominici ◽

Judith Elger ◽

Alba Zappone ◽

Jochem Kück ◽

...

Keyword(s):

Seismic Anisotropy ◽

Seismic Velocity ◽

Metamorphic Rocks ◽

Seismic Velocities ◽

Mafic Rocks ◽

Seismic Properties ◽

The Core ◽

Nappe Complex ◽

Thrust Zone ◽

Mountain Belts

Abstract. Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply-eroded orogens like the Scandinavian Caledonides allow to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications for a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data constrains the origin of this reflectivity. In this study, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. The core and downhole velocities deviate by up to 2 km/s. However, velocities of mafic rocks are generally in close agreement. Seismic anisotropy increases from about 5 to 26 % at depth, indicating a transition from gneissic to schistose foliation. We suggest that differences in the core and downhole velocities are most likely the result of microcracks mainly due to depressurization. Thus, seismic velocity can help to identify mafic rocks on different scales whereas the velocity signature of other lithologies is obscured in core-derived velocities. Metamorphic foliation on the other hand has a clear expression in seismic anisotropy. These results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere. In particular, they show that core log seismic integration via synthetic seismograms requires wireline logging data in any but mafic lithologies.

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An investigation into the genesis of an erratic (retro) eclogite block from Haren, Groningen, the Netherlands

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600023143 ◽

2007 ◽

Vol 86 (2) ◽

pp. 145-157

Author(s):

J. Langendoen ◽

H.L.M. van Roermund

Keyword(s):

The Netherlands ◽

Source Area ◽

Mineral Chemistry ◽

Metamorphic Rocks ◽

Glacial Deposit ◽

Trace Back ◽

Nappe Complex ◽

Seve Nappe Complex ◽

Erratic Block ◽

The Baltic

AbstractIn boulder clays and glacial deposit sands, exposed in the northern part of the Netherlands, erratic blocks of (ultra)high pressure (UHP) metamorphic rocks may be found that originate from the Baltic Shield (Scandinavia). The occurrence of (U)HP metamorphic rocks in Scandinavia is limited to: (1) isolated occurrences within the Scandinavian Caledonides (Western part of Scandinavia); (2) Sveconorvegian rocks from the Halland area, Southwest Sweden; and (3) Kola Peninsula (Northern Scandinavia). For this reason (U)HP rocks form excellent indicator pebbles/rocks that may be used to trace back the source area from where the erratic blocks, found in the Netherlands, were derived. An example of this, an erratic (retro) eclogite block found in Haren, is investigated in the present study using naked eye, light-optical and electron microprobe (EMP) techniques. EMP mineral analyses were used to reconstruct the PT conditions under which the (retro) eclogite was formed (T = 756 °C/min. P = 16,2 kb). This result, in combination with the mineral chemistry of the major rock forming minerals, provides evidence that this erratic block originates from the upper HP tectonic lens exposed in the Caledonian Seve Nappe Complex of Northern Jämtland, Sweden.

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Seismic Properties of a Unique Olivine-Rich Eclogite in the Western Gneiss Region, Norway

Minerals ◽

10.3390/min10090774 ◽

2020 ◽

Vol 10 (9) ◽

pp. 774

Author(s):

Yi Cao ◽

Haemyeong Jung ◽

Jian Ma

Keyword(s):

Seismic Anisotropy ◽

Relative Volume ◽

Ultrahigh Pressure ◽

Seismic Velocities ◽

Western Gneiss Region ◽

Seismic Properties ◽

Rock Types ◽

Deep Crust ◽

Crystal Preferred Orientation ◽

Hydrous Phase

Investigating the seismic properties of natural eclogite is crucial for identifying the composition, density, and mechanical structure of the Earth’s deep crust and mantle. For this purpose, numerous studies have addressed the seismic properties of various types of eclogite, except for a rare eclogite type that contains abundant olivine and orthopyroxene. In this contribution, we calculated the ambient-condition seismic velocities and seismic anisotropies of this eclogite type using an olivine-rich eclogite from northwestern Flemsøya in the Nordøyane ultrahigh-pressure (UHP) domain of the Western Gneiss Region in Norway. Detailed analyses of the seismic properties data suggest that patterns of seismic anisotropy of the Flem eclogite were largely controlled by the strength of the crystal-preferred orientation (CPO) and characterized by significant destructive effects of the CPO interactions, which together, resulted in very weak bulk rock seismic anisotropies (AVp = 1.0–2.5%, max. AVs = 0.6–2.0%). The magnitudes of the seismic anisotropies of the Flem eclogite were similar to those of dry eclogite but much lower than those of gabbro, peridotite, hydrous-phase-bearing eclogite, and blueschist. Furthermore, we found that amphibole CPOs were the main contributors to the higher seismic anisotropies in some amphibole-rich samples. The average seismic velocities of Flem eclogite were greatly affected by the relative volume proportions of omphacite and amphibole. The Vp (8.00–8.33 km/s) and Vs (4.55–4.72 km/s) were remarkably larger than the hydrous-phase-bearing eclogite, blueschist, and gabbro, but lower than dry eclogite and peridotite. The Vp/Vs ratio was almost constant (avg. ≈ 1.765) among Flem eclogite, slightly larger than olivine-free dry eclogite, but similar to peridotite, indicating that an abundance of olivine is the source of their high Vp/Vs ratios. The Vp/Vs ratios of Flem eclogite were also higher than other (non-)retrograded eclogite and significantly lower than those of gabbro. The seismic features derived from the Flem eclogite can thus be used to distinguish olivine-rich eclogite from other common rock types (especially gabbro) in the deep continental crust or subduction channel when high-resolution seismic wave data are available.

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Seismic anisotropy in metamorphic rocks from the COSC-1 borehole, Sweden: A cross-scale investigation from thin section analysis to seismic scales

10.5194/egusphere-egu21-12483 ◽

2021 ◽

Author(s):

Felix Kästner ◽

Simona Pierdominici ◽

Alba Zappone ◽

Luiz F. G. Morales ◽

Anja M. Schleicher ◽

...

Keyword(s):

Seismic Anisotropy ◽

Electron Backscatter Diffraction ◽

Mineralogical Composition ◽

Crystallographic Preferred Orientation ◽

Nappe Complex ◽

Integrative Study ◽

Thrust Zone ◽

Seismic Reflectivity ◽

Anisotropy Model ◽

Thin Section Analysis

Metamorphic and deformed rocks in thrust zones show particularly high seismic anisotropy causing challenges for seismic imaging and interpretation. A good example is the Seve Nappe Complex in J&#228;mtland, Sweden, an exhumed orogenic thrust zone characterized by a strong but incoherent seismic reflectivity and considerable seismic anisotropy. However, only little is known about the origin of the anisotropy in relation to composition, structural influences, and implications for measurements at different seismic scales. We present an integrative study of the seismic anisotropy at different scales combining mineralogical composition, microstructural analyses and seismic laboratory experiments from samples of the 2.5 km-deep COSC-1 borehole. While there is a pronounced crystallographic preferred orientation in most of the core samples, variations in anisotropy correlate strongly with bulk mineral composition and dominant core lithology. Based on three major lithologic different facies (felsic gneiss, amphibole-rich rocks, and mica schists), we propose an anisotropy model for the full length of the borehole, which indicates two prevailing anisotropic units. Comparison of laboratory seismic measurements and electron-backscatter diffraction (EBSD) data reveals a strong scale-dependence, which is more pronounced in the highly deformed, heterogeneous samples. This highlights the need for comprehensive cross-validation of microscale anisotropy analyses with additional lithological data when integrating seismic anisotropy through seismic scales.

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Core-log-seismic integration in metamorphic rocks at the ICDP drilling project COSC-1, Sweden

10.5194/egusphere-egu21-2321 ◽

2021 ◽

Author(s):

Judith Elger ◽

Christian Berndt ◽

Felix Kästner ◽

Simona Pierdominici ◽

Jochem Kück ◽

...

Keyword(s):

Gamma Ray ◽

Sedimentary Basins ◽

Shear Zones ◽

Seismic Profile ◽

Passive Margin ◽

Three Dimensions ◽

Metamorphic Rocks ◽

Metamorphic Overprint ◽

Nappe Complex ◽

Seve Nappe Complex

Continental collision causes deformation in the crust along shear zones. However, the physical and chemical conditions at which these zones operate and the deformation processes that enable up to hundreds of km of tectonic transport are still unclear because of the depth at which they occur and the challenges in imaging them. Ancient exhumed collision zones allow us to investigate these processes much better, for example at the COSC-1 borehole in the central Scandinavian Caledonides. This study combines data from the COSC-1 borehole, such as downhole logging and zero-offset vertical seismic profile data, with 2D and 3D seismic measurements to provide constraints on the spatial lithological and textural configuration of the Seve Nappe Complex. This is one of the few studies that shows that core-log-seismic integration in metamorphic rocks allows to identify the spatial distribution of major lithological units, even though the methodology was originally developed for sedimentary basins in the hydrocarbon industry. Especially gamma ray logs in combination with density data are powerful tools to distinguish between mafic and felsic lithologies in log-core correlation. Reflections in the Seve Nappe Complex are not as distinct as in greater depths but continuous, and our results indicate that they are primarily caused by compositional rather than textural changes. Several of the reflections can be linked to magmatic intrusions, which have been metamorphically overprinted. Their setting indicates that the Seve Nappe Complex consists of the remnants of a volcanic continental margin. It appears that in spite of the metamorphic overprint around 417+/-9 Ma, the original configuration of the volcanic passive margin is partly preserved in the Seve Nappe Complex and that it outlasted continent-continent collision, including the nappe emplacement. Thus, an integration of borehole and three-dimensional geophysical data can image lithological changes that can then be extrapolated in three dimensions to arrive at a better understanding of the composition and geometry at mid-crustal levels. Furthermore, our results suggest that ductile-deformed middle crustal reflectivity is primarily a function of pre-orogenic lithological variations which has to be considered when deciphering mountain building processes.

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Tomography image of double high-velocity heterogeneity beneath the Eastern Alps from the AlpArray data

10.5194/egusphere-egu2020-7728 ◽

2020 ◽

Author(s):

Jaroslava Plomerová ◽

Helena Žlebčíková ◽

György Hetényi ◽

Luděk Vecsey ◽

Vladislav Babuška ◽

...

Keyword(s):

Bohemian Massif ◽

High Velocity ◽

Seismic Anisotropy ◽

Body Wave ◽

Eastern Alps ◽

Quality Data ◽

Seismic Velocities ◽

Adriatic Plate ◽

The Alps ◽

Mountain Belts

Convergence between the European and African plates formed the Alps and the neighbouring mountain belts. We present results based on teleseismic body-wave data from the AlpArray-EASI complementary experiment (2014-2015, Het&#233;nyi et al., Tectonophysics 2018) and the AlpArray Seismic Network (Het&#233;nyi et al., Surv. Geophys. 2018). Tomography of seismic velocities in the upper mantle, as well as seismic anisotropy study along a ca. 200 km broad and 540 km long north-south transect (crossing the Bohemian Massif in the north, the East-Alpine root, and reaching the Adriatic Sea in the south), image the steeply northward dipping East-Alpine root, dominated by the Adriatic plate, steady southward thickening of the lithosphere beneath the Bohemian Massif and distinct regional variations of mantle lithosphere fabrics modelled in 3D. These characteristics imply complex, domain-like architecture of the collisional zone of the European/Adriatic plates beneath the Alps. Thanks to the close spacing of the AlpArray stations and high-quality data, the high-resolution tomography resolved for the first time two neighbouring high-velocity northward-dipping heterogeneities beneath the Eastern Alps, instead of one thick root of the lithosphere. The southern one, which we relate to the Adriatic plate, is more distinct, the northern one is less pronounced, it delaminates at ~100km depth and diminishes in direction toward the Central Alps. It may represent a remnant of an early phase subduction of the European plate with the switched polarity (relative to the polarity in the Western Alps), or a preceding phase of the Adriatic subduction.

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Estudio del proceso de lavado de contenedores para eliminar tiempos y movimientos innecesarios, caso: Wash Containers S.A de C.V.

Revista de Ingeniería Tecnológica ◽

10.35429/jten.2019.10.3.25.36 ◽

2020 ◽

pp. 25-36

Author(s):

Juan Alfredo Lino-Gamiño ◽

Carlos Méndez-González ◽

Eduardo José Salazar-Araujo ◽

Pablo Adrián Magaña-Sánchez

Keyword(s):

Business Process ◽

Value Chain ◽

Process Management ◽

Core Business ◽

The Core ◽

Washing Process ◽

Overall Performance ◽

The Times

In the value chain it is important to keep in mind the core business of the company, since it depends largely on the competitiveness of the company and its overall performance, bearing in mind that all business indicators depend on it. In this work we will study the washing process within the company WASH CONTAINERS SA DE CV, to improve the washing processes and in this way reduce times and movements in the process leading the company to reduce costs considerably within the operations company daily, having a more competitive operation and with greater profit margin in its business process. Goals: It Improve the logistics of the movement of containers for washing and with it the core business of the company. Methodology: The action research will be applied applying Business Process Management for the improvement of processes in situ, it will be developed in a certain period of time and with that it will establish an improvement projection. Contribution: The improvement of the times for the disposal of the containers and their subsequent use, allows a better competitiveness and with it the income of the company, on the other hand, the transport companies improve in performance in quantity, quality of disposition and with it their income.

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