14 Works

GEOWiki@LMU – an online platform for university and school education in geosciences

Magdalena Luise Plitz , Katrin Mühlberg , Donja Aßbichler , Laurin Lidl , Malte Junge & Eileen Eckmeier
GEOWiki@LMU is a constantly growing open platform for the promotion of practical and research-oriented knowledge acquisition elaborated by and for students of earth sciences. The contents are developed by students in courses or on their own initiative in interdisciplinary teams. All topics are discussed in weekly editorial online-meetings and revised in close collaboration with lecturers. One of the main goals is to provide information on methods relevant to geosciences. Focus is on field, preparation and...

Biomineralization processes in low-temperature, shallow-water hydrothermal vent at Tagoro submarine volcano, El Hierro Island (Central East Atlantic)

Blanca Rincón-Tomás , Francisco Javier González , Luis Somoza , James R. Hein , Teresa Medialdea , Esther Santofimia, Egidio Marino & Pedro Madureira
A novel hydrothermal system was discovered at the summit of the underwater Tagoro volcano at 89–120 m depth after the 2011–2012 eruption, characterized by the low-temperature venting of Fe-rich fluids that produced a seafloor draped by extensive Fe-flocculate deposits. The basanite-hornitos are capped by mm- to cm-thick hydrothermally derived Fe-oxyhydroxide sediment and contain micro-cracks and degasification vesicles filled by sulfides (mostly pyrite) and covered by sulfur-oxidizing bacterial mats. Electron microprobe studies on Fe-oxyhydroxide crusts show...

Residual gravity anomalies in the Western Mediterranean shed light on complex crust

Hans-Jürgen Götze & Philipp Tabelow
The data sets presented here are used for the preparations of a 3-dimensional modelling of the gravity field in the Western Mediterranean/Ligurian Sea. As part of the AlpArray initiative and the German priority program MB-4D, various compilations of the gravity field are available: Bouguer and Free Air Anomaly, as well as variously calculated residual fields that provide new insight into crustal and lithospheric structures. The anomalies have been processed according to modern standards. The recalculations...

Internal Architecture of a carbonate ramp exposed to high amplitude sea-level fluctuations: Evidence from the NW shelf of Australia

Maximilian Hallenberger , Lars Reuning , Stefan Back , Stephen J. Gallagher , Hokuto Iwatani & Katja Lindhorst
The North West Shelf of Australia represents an extensive tropical carbonate ramp and forms an important template for the interpretation of similar systems found within the sedimentary record. Yet, little is known about the development of the distally steepened ramp during the mid-to-late Quaternary, a period during which NW-Australia was subject to high-frequency glacioeustatic changes in sea level and climate. This research presents core and seismic-reflection data from a mid to outer ramp transect at...

Microplastics as a sedimentary component in reefs systems: A case study from the Java Sea

Amanda Utami , Lars Reuning , Olga Konechnaya & Jan Schwarzbauer
Microplastic pollution has been reported from coral reef systems all over the tropics. Exposure to microplastics has several negative impacts on coral health. Despite this potential risk for reef systems, the controlling processes for microplastics dispersion and accumulation in reef sediments are still understudied. Presented here is a study of microplastics (125 µm – 5 mm) distribution in two tropic atoll reef platforms in Kepulauan Seribu, Indonesia. Sediment samples were collected in different facies zones...

Pre-processing of gravity data for 3 D-modelling of the lithospheric underground in the Ligurian Sea

Philipp Tabelow & Hans-Jürgen Götze
The Ligurian Sea in the western Mediterranean Sea is a back arc basin created through the Apennines Calabrian subduction zone between 30 and 15 Ma ago. The inner geological structure of this basin is not well known. To improve the knowledge about the density distribution of the crust and lithosphere, we performed a pre-processing of gravity data prior to 3D-modelling. This work is related to research in the MB-4D priority and AlpArray project. The satellite...

Structure and density configuration of Germany’s subsurface: 3-D-Deutschland, an updated three-dimensional lithospheric-scale model

Denis Anikiev , Judith Bott , Mauro Cacace , Hans-Jürgen Götze & Magdalena Scheck-Wenderoth
With this study we revise and improve the three-dimensional lithospheric-scale structural and density model of Germany (3-D-D). Major shortcomings of this model resulted from joining three regional 3-D models that were poorly covered by data at their margins. Merging into a larger model revealed structural inconsistencies in these “marginal” domains. In order to resolve discrepancies between the units in a more consistent way we integrate newly available data from seismic reprocessing, tomography, and use 3-D...

How did anoxic conditions affect nitrogen fixing Cyanobacteria on early Earth?

Arianna Gallo , Katharina Ebel , Thorsten Bauersachs , Achim Herrmann & Michelle M. Gehringer
The Earth’s atmosphere was without free oxygen until the Great Oxygenation Event, thought to have been driven by oxygenic photosynthesis. The expansion of early Cyanobacteria was proposed to be restricted by the lack of bioavailable nitrogen. The effects of an anoxic Archean atmosphere on the growth of a the nitrogen fixing Cyanobacterium Nostoc sp. PCC7524 was compared to control cultures grown under present day atmospheric levels (PAL) of O2 and CO2. Additionally, we assessed how...

Millennial variability, hydrological and limnological changes during MIS3-2 in Lake Petén Itzá, Guatemala

Rodrigo Martinez-Abarca, Michelle Abstein , Philipp Hoelzmann , Thorsten Bauersachs , Liseth Pérez , Mona Stockhecke , Sergio Cohuo Duran & Antje Schwalb
Heinrich Stadials and Greenland Interstadials are abrupt climate variations that are observed in the Northern Hemisphere throughout Marine Isotopic Stages (MIS) 3-2. Lake Petén Itzá, northern Guatemala, is a key site for paleoclimate investigations due to its sensitivity to changes in climate forcing such as the Intertropical Convergence Zone (ITCZ) and the Atlantic Meridional Overturning Circulation (AMOC). In this study, we reconstructed the hydrology and limnology of Lake Petén Itzá during MIS3-2 based on geochemical...

A profile through ancient fast-spreading oceanic crust in the Wadi Gideah, Oman ophiolite – reference frame for the crustal drillings within the ICDP Oman Drilling Project

Jürgen Koepke , Dieter Garbe-Schönberg , Dominik Mock & Samuel Müller
The Oman Ophiolite is the largest and best-investigated piece of ancient oceanic lithosphere on our planet. This ophiolite was target of the Oman Drilling Project (OmanDP) within the frame of ICDP (International Continental Scientific Drilling Program) which aimed to establish a comprehensive drilling program in order to understand essential processes related to the geodynamics of mid-ocean ridges, as magmatic formation, cooling/alteration by seawater-derived fluids, and the weathering with focus on the carbonatisation of peridotites. Over...

The ICDP Oman Drilling Project – Implications from drill core GT1 on magmatic processes beneath fast-spreading mid-ocean ridges

Dominik Mock , David Axford Neave , Samuel Müller , Dieter Garbe-Schönberg , Benoit Ildefonse , Jürgen Koepke & Oman Drilling Project Science Team
A key aim of the ICDP Oman Drilling Project is to constrain magmatic processes beneath fast-spreading mid-ocean ridges. Several drill cores from the Samail ophiolite (Oman), which is regarded as the best-preserved piece of ancient oceanic lithosphere on land, were obtained. Drill core GT1 covers about 400 m from the layered gabbro section between ~1200 and 800 m above the mantle transition zone (maM). The vast majority of the samples recovered are (olivine-) gabbros with...

The compilation of the new Alpine gravity maps - from the work of the AlpArray Gravity Research Group

Pavol Zahorec , Juraj Papco , Roman Pasteka , Miroslav Bielik , Sylvain Bonvalot , Carla Braitenberg, Jörg Ebbing , Gerald Gabriel , Andrej Gosar , Adam Grand , Hans-Jürgen Götze & György Hetényi
The international networking initiative AlpArray Gravity Research Group (AAGRG) focused on the compiling homogeneous surface-based gravity datasets across the Alps and adjacent areas, on creating digital data sets for Bouguer and Free Air anomalies. In 2016/17 all ten countries around the Alps have agreed to contribute with point or gridded gravity data and data processing techniques to a recompilation of the Alpine gravity field in an area which is limited by 2° to 23° East...

Contrasting intensity of aragonite dissolution in glacial vs. interglacial intervals of a sea-level controlled subtropical carbonate succession

Lars Reuning , Hanaa Deik , Benjamin Petrick , Hideko Takayanagi , Yasufumi Iryu , Margot Courtillat & Maria-Angela Bassetti
Aragonite and high-Mg calcite are abundant in modern, neritic temperate water systems but are nearly absent from their fossil counterparts. Dissolution of these metastable mineral phases will often leave no visible trace in the sedimentary record. Furthermore, it has been proposed that dolomitization is driven by reflux of mesohaline, aragonite undersaturated waters and that dolomite crystal growth is tightly coupled to aragonite dissolution in a temperate carbonate slope system. This study aims to clarify the...

Imaging the warm lithospheric mantle in the Mediterranean-Alpine region: integrated thermochemical inversion of surface wave dispersion, heat flow and elevation data.

Carlos Clemente , Javier Fullea , Amr El-Sharkawy , Thomas Meier , Sergei Lebedev & Thor Hansteen
Here we investigate the thermal structure of the lithosphere in the Alpine-Mediterranean region. We focus on areas characterized by negative velocity anomalies according to a lithosphere-upper mantle surface-wave tomography study (El-Sharkawy et al., 2020) to analyze possible lithospheric thinning and melting. Surface-wave, phase-velocity curves were determined by interstation cross-correlation measurements and inverted for a set of phase-velocity maps, spanning a broad period range. We invert fundamental mode Rayleigh and Love dispersion curves together with surface...

Registration Year

  • 2022
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Affiliations

  • Kiel University
    13
  • Leibniz University Hannover
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  • RWTH Aachen University
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  • Tecnológico Nacional de México, Mexico
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  • TU-Braunschweig, Braunschweig, Germany
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  • University of Lausanne
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  • National Research Institute of Astronomy and Geophysics
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  • Tohoku University
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  • University of Melbourne
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  • University of Minnesota-Duluth, USA
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