| 1. |
- Wilhelms, Frank, et al.
(author)
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The EPICA Dronning Maud Land deep drilling operation
- 2014
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In: Annals of Glaciology. - 0260-3055 .- 1727-5644. ; 55:68, s. 355-366
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Journal article (peer-reviewed)abstract
- We report on the EPICA Dronning Maud Land (East Antarctica) deep drilling operation. Starting with the scientific questions that led to the outline of the EPICA project, we introduce the setting of sister drillings at NorthGRIP and EPICA Dome C within the European ice-coring community. The progress of the drilling operation is described within the context of three parallel, deep-drilling operations, the problems that occurred and the solutions we developed. Modified procedures are described, such as the monitoring of penetration rate via cable weight rather than motor torque, and modifications to the system (e.g. closing the openings at the lower end of the outer barrel to reduce the risk of immersing the drill in highly concentrated chip suspension). Parameters of the drilling (e.g. corebreak force, cutter pitch, chips balance, liquid level, core production rate and piece number) are discussed. We also review the operational mode, particularly in the context of achieved core length and piece length, which have to be optimized for drilling efficiency and core quality respectively. We conclude with recommendations addressing the design of the chip-collection openings and strictly limiting the cable-load drop with respect to the load at the start of the run.
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| 2. |
- Bott, Lukas Thomas, et al.
(author)
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Coulomb dissociation of O-16 into He-4 and C-12
- 2023
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In: NUCLEAR PHYSICS IN ASTROPHYSICS - X, NPA-X 2022. - : EDP Sciences. - 2100-014X. ; 279
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Conference paper (peer-reviewed)abstract
- We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4.
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| 3. |
- Piepjohn, Karsten, et al.
(author)
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Mesozoic structural evolution of the New Siberian Islands
- 2017
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In: Geological Society Special Publication. - London : Geological Society of London. - 0305-8719 .- 2041-4927. ; 460
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Journal article (peer-reviewed)abstract
- The New Siberian Islands are affected by a number of Mesozoic tectonic events. Theoldest event (D1a) is characterized by NW-directed thrusting within the South Anyui SutureZone combined with north – south-trending sinistral strike-slip in the foreland during the Early Cre-taceous. This compressional deformation was followed by dextral transpression along north –south-trending faults, which resulted in NE – SW shortening in the Kotelny Fold Zone (D1b).The dextral deformation can be related to a north – south-trending boundary fault zone west ofthe New Siberian Islands, which probably represented the Laptev Sea segment of the AmerasiaBasin Transform Fault in pre-Aptian – Albian times. The presence of a transform fault west ofthe islands may be an explanation for the long and narrow sliver of continental lithosphere ofthe Lomonosov Ridge and the sudden termination of the South Anyui Suture Zone against the pre-sent Laptev Sea Rift System. The intrusion of magmatic rocks 114 myr ago was followed by NW –SE-trending sinistral strike-slip faults of unknown origin (D2). In the Late Cretaceous – Paleocene,east – west extension (D3) west of the New Siberian Islands initiated the development of the LaptevSea Rift System, which continues until today and is largely related to the development of the Eur-asian Basin.
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