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Andreas Jahn - One of the best experts on this subject based on the ideXlab platform.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
Dirk Scherler - One of the best experts on this subject based on the ideXlab platform.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
T Kenkmann - One of the best experts on this subject based on the ideXlab platform.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
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structural record of an oblique impact
Earth and Planetary Science Letters, 2006Co-Authors: Dirk Scherler, T Kenkmann, Andreas JahnAbstract:Abstract Most impactors strike their target at an oblique angle. The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and other morphological, structural or geophysical criteria are needed. Here, we present structural details from the central uplift of the Upheaval Dome impact structure that are diagnostic of the kinematics during crater collapse and central uplift formation. A characteristic imbrication of thrust slices towards the SE, the pattern of strata orientation within the central uplift, dominant radial faults that accommodated NW–SE shortening and an elliptical bedding outline indicate that the displacement field during crater collapse has not been axial symmetric. Instead, an additional Lateral Component, roughly towards the SE, is preserved in the internal structure of the central uplift. The structural asymmetries are largest in the core of the central uplift and disappear outwards, thereby preserving the large-scale circular shape of the main structural elements (rim monocline, ring syncline). Comparison with numerical models of oblique impacts suggests that the additional Lateral displacement Component reflects a downrange material transport during the initial stages of central uplift formation. Similar patterns are identified in other impact structures and may serve as general criteria for identifying the impact direction of deeply eroded impact structures in sedimentary targets.
Tham Tran - One of the best experts on this subject based on the ideXlab platform.
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generation of a north south magnetic field Component from variations in the photospheric magnetic field
Solar Physics, 2016Co-Authors: R K Ulrich, Tham TranAbstract:We address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere that is called the source surface where the solar wind originates. This calculation must overcome a widely used fundamental assumption about the source surface – the field is normally required to be purely radial at the source surface. Our model rests on the fact that a change in the radial field strength at the source surface is a change in the field line density. Surrounding field lines must move Laterally to accommodate this field line density change. As the outward wind velocity drags field lines past the source surface, this Lateral Component of motion produces a tilt, implying there is a transverse Component to the field. An analytic method of calculating the Lateral translation speed of the field lines is developed. We apply the technique to an interval of approximately two Carrington rotations at the beginning of 2011 using 2-h averages of data from the Helioseismic Magnetic Imager instrument onboard the Solar Dynamics Observatory spacecraft. We find that the value of the transverse magnetic field is dominated on a global scale by the effects of high-latitude concentrations of field lines that are buffeted by supergranular motions.
Irina Arechvo - One of the best experts on this subject based on the ideXlab platform.
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Syringocystadenoma Papilliferum of the Bony External Auditory Canal: A Rare Tumor in a Rare Location
Hindawi Limited, 2013Co-Authors: Anastasija Arechvo, Svajunas Balseris, Laura Neverauskiene, Irina ArechvoAbstract:Tumors originating from ceruminous glands are rare lesions of the external auditory canal. The lack of specific clinical and radiological signs makes their diagnosis challenging. We report the case of an exceptionally rare benign tumor, a syringocystadenoma papilliferum (SCAP), in an atypical location in the bony segment of the external auditory canal with uncommon clinical signs. The special traits of the case included the following: the most Lateral Component of the tumor was macroscopically cystic and a granular myringitis with an obstructing keratin mass plug was observed behind the mass. The clinical, audiological, radiological, and histological characteristics of the neoplasm are consequently presented. Intraoperative diagnosis of the epidermal cyst was proposed. The final diagnosis of SCAP was determined only by histological analysis after the surgical excision. The educational aspects of the case are critically discussed
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Syringocystadenoma Papilliferum of the Bony External Auditory Canal: A Rare Tumor in a Rare Location
2013Co-Authors: Anastasija Arechvo, Svajunas Balseris, Laura Neverauskiene, Irina ArechvoAbstract:Copyright © 2013 Anastasija Arechvo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tumors originating from ceruminous glands are rare lesions of the external auditory canal. The lack of specific clinical and radiological signs makes their diagnosis challenging. We report the case of an exceptionally rare benign tumor, a syringocystadenoma papilliferum (SCAP), in an atypical location in the bony segment of the external auditory canal with uncommon clinical signs. The special traits of the case included the following: the most Lateral Component of the tumor was macroscopically cystic and a granular myringitis with an obstructing keratin mass plug was observed behind the mass.The clinical, audiological, radiological, and histological characteristics of the neoplasm are consequently presented. Intraoperative diagnosis of the epidermal cyst was proposed. The final diagnosis of SCAP was determined only by histological analysis after the surgical excision. The educational aspects of the case are critically discussed. 1
