TY - JOUR A1 - Korges, Maximilian A1 - Weis, Philipp A1 - Andersen, Christine T1 - The role of incremental magma chamber growth on ore formation in porphyry copper systems JF - Earth & planetary science letters N2 - Porphyry copper deposits are formed by fluids released from felsic magmatic intrusions of batholithic dimensions, which are inferred to have been incrementally built up by a series of sill injections. The growth of the magma chamber is primarily controlled by the volumetric injection rate from deeper-seated magma reservoirs, but can further be influenced by hydrothermal convection and fluid release. To quantify the interplay between magma chamber growth, volatile expulsion and hydrothermal fluid flow during ore formation, we used numerical simulations that can model episodic sill injections in concert with multi-phase fluid flow. To build up a magma chamber that constantly maintains a small region of melt within a period of about 50 kyrs, an injection rate of at least 1.3 x 10(-3) km(3)/y is required. Higher magma influxes of 1.9 to 7.6 x 10(-3) km(3)/y are able to form magma chambers with a thickness of 2 to 3 km. Such an intrusion continuously produces magmatic volatiles which can precipitate a copper ore shell in the host rock about 2 km above the fluid injection location. The steady fluid flux from such an incrementally growing magma chamber maintains a stable magmatic fluid plume, precipitating a copper ore shell in a more confined region and resulting in higher ore grades than the ones generated by an instantaneous emplacement of a voluminous magma chamber. Our simulation results suggest that magma chambers related to porphyry copper deposits form by rapid and episodic injection of magma. Slower magma chamber growth rates more likely result in barren plutonic rocks, although they are geochemically similar to porphyry-hosting plutons. However, these low-frequency sill injection events without a significant magma chamber growth can generate magmatic fluid pulses that can reach the shallow subsurface and are typical for high-sulfidation epithermal deposits. KW - pluton KW - magma chamber KW - porphyry copper deposits KW - magmatic sill KW - numerical modeling KW - ore deposit Y1 - 2020 U6 - https://doi.org/10.1016/j.epsl.2020.116584 SN - 0012-821X SN - 1385-013X VL - 552 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - GEN A1 - Bilbao-Lasa, Peru A1 - Jara-Muñoz, Julius A1 - Pedoja, Kevin A1 - Álvarez, Irantzu A1 - Aranburu, Arantza A1 - Iriarte, Eneko A1 - Galparsoro, Ibon T1 - Submerged marine terraces identification and an approach for numerical modeling the sequence formation in the Bay of Biscay (Northeastern Iberian Peninsula) T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Submerged sequences of marine terraces potentially provide crucial information of past sea-level positions. However, the distribution and characteristics of drowned marine terrace sequences are poorly known at a global scale. Using bathymetric data and novel mapping and modeling techniques, we studied a submerged sequence of marine terraces in the Bay of Biscay with the objective to identify the distribution and morphologies of submerged marine terraces and the timing and conditions that allowed their formation and preservation. To accomplish the objectives a high-resolution bathymetry (5 m) was analyzed using Geographic Information Systems and TerraceM(R). The successive submerged terraces were identified using a Surface Classification Model, which linearly combines the slope and the roughness of the surface to extract fossil sea-cliffs and fossil rocky shore platforms. For that purpose, contour and hillshaded maps were also analyzed. Then, shoreline angles, a geomorphic marker located at the intersection between the fossil sea-cliff and platform, were mapped analyzing swath profiles perpendicular to the isobaths. Most of the submerged strandlines are irregularly preserved throughout the continental shelf. In summary, 12 submerged terraces with their shoreline angles between approximately: -13 m (T1), -30 and -32 m (T2), -34 and 41 m (T3), -44 and -47 m (T4), -49 and 53 m (T5), -55 and 58 m (T6), -59 and 62 m (T7), -65 and 67 m (T8), -68 and 70 m (T9), -74 and -77 m (T10), -83 and -86 m (T11) and -89 and 92 m (T12). Nevertheless, the ones showing the best lateral continuity and preservation in the central part of the shelf are T3, T4, T5, T7, T8, and T10. The age of the terraces has been estimated using a landscape evolution model. To simulate the formation and preservation of submerged terraces three different scenarios: (i) 20-0 ka; (ii) 128-0 ka; and (iii) 128-20 ka, were compared. The best scenario for terrace generation was between 128 and 20 Ka, where T3, T5, and T7 could have been formed. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1414 KW - marine terrace KW - submerged sequence KW - digital bathymetric model KW - TerraceM KW - numerical modeling KW - Bay of Biscay Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517815 SN - 1866-8372 IS - 47 ER - TY - JOUR A1 - Bilbao-Lasa, Peru A1 - Jara-Muñoz, Julius A1 - Pedoja, Kevin A1 - Álvarez, Irantzu A1 - Aranburu, Arantza A1 - Iriarte, Eneko A1 - Galparsoro, Ibon T1 - Submerged marine terraces identification and an approach for numerical modeling the sequence formation in the Bay of Biscay (Northeastern Iberian Peninsula) JF - Frontiers in Earth Science N2 - Submerged sequences of marine terraces potentially provide crucial information of past sea-level positions. However, the distribution and characteristics of drowned marine terrace sequences are poorly known at a global scale. Using bathymetric data and novel mapping and modeling techniques, we studied a submerged sequence of marine terraces in the Bay of Biscay with the objective to identify the distribution and morphologies of submerged marine terraces and the timing and conditions that allowed their formation and preservation. To accomplish the objectives a high-resolution bathymetry (5 m) was analyzed using Geographic Information Systems and TerraceM(R). The successive submerged terraces were identified using a Surface Classification Model, which linearly combines the slope and the roughness of the surface to extract fossil sea-cliffs and fossil rocky shore platforms. For that purpose, contour and hillshaded maps were also analyzed. Then, shoreline angles, a geomorphic marker located at the intersection between the fossil sea-cliff and platform, were mapped analyzing swath profiles perpendicular to the isobaths. Most of the submerged strandlines are irregularly preserved throughout the continental shelf. In summary, 12 submerged terraces with their shoreline angles between approximately: -13 m (T1), -30 and -32 m (T2), -34 and 41 m (T3), -44 and -47 m (T4), -49 and 53 m (T5), -55 and 58 m (T6), -59 and 62 m (T7), -65 and 67 m (T8), -68 and 70 m (T9), -74 and -77 m (T10), -83 and -86 m (T11) and -89 and 92 m (T12). Nevertheless, the ones showing the best lateral continuity and preservation in the central part of the shelf are T3, T4, T5, T7, T8, and T10. The age of the terraces has been estimated using a landscape evolution model. To simulate the formation and preservation of submerged terraces three different scenarios: (i) 20-0 ka; (ii) 128-0 ka; and (iii) 128-20 ka, were compared. The best scenario for terrace generation was between 128 and 20 Ka, where T3, T5, and T7 could have been formed. KW - marine terrace KW - submerged sequence KW - digital bathymetric model KW - TerraceM KW - numerical modeling KW - Bay of Biscay Y1 - 2020 U6 - https://doi.org/10.3389/feart.2020.00047 SN - 2296-6463 VL - 8 IS - 47 SP - 1 EP - 20 PB - Frontiers Media CY - Lausanne ER - TY - THES A1 - Munz, Matthias T1 - Water flow and heat transport modelling at the interface between river and aquifer T1 - Wasserfluss- und Wärmetransportmodellierung an der Schnittstelle zwischen Fluss und Grundwasserleiter N2 - The functioning of the surface water-groundwater interface as buffer, filter and reactive zone is important for water quality, ecological health and resilience of streams and riparian ecosystems. Solute and heat exchange across this interface is driven by the advection of water. Characterizing the flow conditions in the streambed is challenging as flow patterns are often complex and multidimensional, driven by surface hydraulic gradients and groundwater discharge. This thesis presents the results of an integrated approach of studies, ranging from the acquisition of field data, the development of analytical and numerical approaches to analyse vertical temperature profiles to the detailed, fully-integrated 3D numerical modelling of water and heat flux at the reach scale. All techniques were applied in order to characterize exchange flux between stream and groundwater, hyporheic flow paths and temperature patterns. The study was conducted at a reach-scale section of the lowland Selke River, characterized by distinctive pool riffle sequences and fluvial islands and gravel bars. Continuous time series of hydraulic heads and temperatures were measured at different depths in the river bank, the hyporheic zone and within the river. The analyses of the measured diurnal temperature variation in riverbed sediments provided detailed information about the exchange flux between river and groundwater. Beyond the one-dimensional vertical water flow in the riverbed sediment, hyporheic and parafluvial flow patterns were identified. Subsurface flow direction and magnitude around fluvial islands and gravel bars at the study site strongly depended on the position around the geomorphological structures and on the river stage. Horizontal water flux in the streambed substantially impacted temperature patterns in the streambed. At locations with substantial horizontal fluxes the penetration depths of daily temperature fluctuations was reduced in comparison to purely vertical exchange conditions. The calibrated and validated 3D fully-integrated model of reach-scale water and heat fluxes across the river-groundwater interface was able to accurately represent the real system. The magnitude and variations of the simulated temperatures matched the observed ones, with an average mean absolute error of 0.7 °C and an average Nash Sutcliffe Efficiency of 0.87. The simulation results showed that the water and heat exchange at the surface water-groundwater interface is highly variable in space and time with zones of daily temperature oscillations penetrating deep into the sediment and spots of daily constant temperature following the average groundwater temperature. The average hyporheic flow path temperature was found to strongly correlate with the flow path residence time (flow path length) and the temperature gradient between river and groundwater. Despite the complexity of these processes, the simulation results allowed the derivation of a general empirical relationship between the hyporheic residence times and temperature patterns. The presented results improve our understanding of the complex spatial and temporal dynamics of water flux and thermal processes within the shallow streambed. Understanding these links provides a general basis from which to assess hyporheic temperature conditions in river reaches. N2 - Die Interaktion zwischen Oberflächenwasser und Grundwasser hat einen entscheidenden Einfluss auf die Wasserqualität und die ökologische Beschaffenheit von Seen, Flüssen und aquatischen Ökosystemen. Der Austausch von Wärme und gelösten Substanzen zwischen diesen beiden Kompartimenten ist maßgeblich durch die Austauschraten und die Strömungsrichtung des Wassers beeinflusst. Somit ist die Charakterisierung dieser beiden Größen in dem Übergangsbereich zwischen Oberflächenwasser und Grundwasser von besonderer Bedeutung. Diese Arbeit präsentiert die Entwicklung und Anwendung von Methoden zur Untersuchung der zeitlichen und räumlichen Dynamik des Wasser- und Wärmeflusses an der Schnittstelle zwischen Oberflächenwasser und Grundwasser. Die Arbeit besteht im Wesentlichen aus zwei Schwerpunkten. Der erste Schwerpunkt beinhaltet die Entwicklung und Bewertung von analytischen und numerischen Methoden zur Bestimmung der horizontalen Strömungsrichtung und Austauschraten unter Verwendung von kontinuierlich gemessenen Temperaturzeitreihen entlang vertikaler Profile im gesättigten Sediment. Flussbetttemperaturen können relativ einfach und kostengünstig entlang eines Flussabschnittes in verschiedenen Tiefen und unterschiedlichsten Flussbettsedimenten (organisch, sandig bis grob kiesig) gemessen werden. Die Hauptverwendung solcher Temperaturprofile ist bisher auf die analytische Quantifizierung vertikaler Austauschraten limitiert. Im Rahmen dieser Arbeit wurde ein Ansatz entwickelt, der eine punktuelle Ermittlung der horizontalen Strömungs-komponente, basierend auf der Veränderung der täglichen Temperaturamplitude mit zunehmender Tiefe, ermöglicht. Weiterhin wurde ein inverser, numerischer Ansatz entwickelt, der die ein-dimensionale Wärmetransportgleichung numerisch löst und mittels inverser Optimierungsalgorithmen die simulierten Temperaturen bestmöglich an die gemessenen Flussbetttemperaturen anpasst. Diese Methode ermöglicht die automatische, zeitlich variable Quantifizierung vertikaler Austauschraten an der Schnittstelle zwischen Oberflächenwasser und Grundwasser sowie eine einfache Unsicherheitsbetrachtung aufgrund der zugrunde liegenden Parameterunsicherheiten. Der zweite Schwerpunkt der Arbeit liegt auf der Anwendung der entwickelten Methoden und der Erstellung eines dreidimensionalen Simulationsmodelles entlang eines Flussabschnittes der Selke. Numerische Strömungs- und Stofftransportmodelle ermöglichen die gekoppelte Simulation von Fließprozessen im offenen Gerinne und im darunter liegenden porösen Medium. Die Parametrisierung des Modells erfolgte anhand empirischer Daten die im Untersuchungsgebiet detailliert erhoben wurden. Die Simulationsergebnisse zeigten zum einen gebietsspezifische Gegebenheiten auf, ermöglichten darüber hinaus jedoch auch die Beschreibung allgemeiner Muster und Zusammenhänge welche die Wasserfluss- und Wärmetransportprozesse an der Schnittstelle zwischen Oberflächenwasser und Grundwasser beeinflussen. So zeigten die Ergebnisse dieser Arbeit, dass maßgeblich die natürlich vorhandenen Flussbettstrukturen die Austauschraten und die Strömungsrichtung zwischen Oberflächenwasser und Grundwasser beeinflussen und somit den hyporheischen Austausch bestimmen. Wichtige Einflussfaktoren auf die untersuchten Austauschprozesse waren die Lage im Gerinne relativ zur Flussbettstruktur und der vorherrschende Wasserstand (Abfluss). Bedingt durch den Wasser- und Wärmeaustausch prägten sich im Untersuchungsgebiet Bereiche aus in denen die täglichen Temperaturschwingungen tief in das Sediment eindringen (Anstrombereich der Flussbettstrukturen), als auch Bereiche in denen relativ konstante Temperaturen, nahe der Grundwassertemperatur, vorherrschten. Die durchschnittliche Temperatur in der hyporheischen Zone wurde durch die saisonalen Temperaturschwankungen im Oberflächenwasser dominiert, wobei die Temperaturen entlang einzelner Fließpfade stark von der Verweilzeit des Oberflächen- oder Grundwassers im gesättigten Sediment und dem Temperaturgradienten zwischen Fluss und Grundwasser abhängig waren. Trotz der Komplexität dieser Zusammenhänge, ermöglichten die Simulationsergebnisse die Ableitung einer allgemeinen empirischen Beziehung zwischen den hyporheischen Verweilzeiten und Temperaturmustern. Sowohl die Verweilzeiten als auch die Temperatur im gesättigten Sediment haben einen entscheiden Einfluss auf biogeochemische Prozesse in dem Übergangsbereich zwischen Oberflächenwasser und Grundwasser und sind somit von besonderer Bedeutung für die Wasserqualität von Seen, Flüssen und aquatischen Ökosystemen. KW - surface water-groundwater interaction KW - Oberflächenwasser-Grundwasser Interaktion KW - hyporheic zone KW - hyporheische Zone KW - numerical modeling KW - numerische Modellierung KW - heat transport KW - Wärmetransport KW - temperature KW - Temperatur Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404319 ER -