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Als Humboldt sein 1804 geschriebenes Tagebuch seiner Reise von Mexico City nach Veracruz 1853 nochmals sichtete, schrieb er an den Rand einer Passage die kritischen Worte “Alte neptunistische Verrücktheiten!” Dieser Text und seine spätere Randbemerkung beweisen nun endgültig, daß Humboldt noch gegen Ende seiner Amerikareise Neptunist war, was von Forschern oft bezweifelt worden war. Seltsamerweise hat Humboldt dieses Manuskript nicht mit in die Tagebücher aufgenommen, als er sie gegen Ende seines Lebens in 9 Hefte neu binden ließ. Der Nachlaß Humboldts galt zusammen mit der Autographensammlung der Staatsbibliothek Berlin seit der Auslagerung im zweiten Weltkrieg als verschollen. Er befindet sich heute in Krakau, wo ich diesen Tagebuchteil vor einiger Zeit entdeckte, das nun eine wertvolle Ergänzung zur Edition der Tagebücher durch Margot Faak bildet. Der folgende Text stellt diesen Tagebuchteil vor und zeigt die Entwicklung einzelner Ansichten Humboldts in naturwissenschaftlichen Disziplinen, die z. T. paradigmatische Wandel von Theorien - beispielsweise in der Geologie - anzeigen.
Inhalt:
- Kristian Köchy: Das Ganze der Natur – Alexander von Humboldt und das romantische Forschungsprogramm
- Gerhard Kortum: „Alexander von Humboldt“ als Name für Forschungsschiffe vor dem Hintergrund seiner meereskundlichen Arbeiten
- Ulrike Leitner: „Anciennes folies neptuniennes!“ Über das wiedergefundene „Journal du Mexique à Veracruz“ aus den mexikanischen Reisetagebüchern A. v. Humboldts
- Oliver Lubrich: „Egipcios por doquier“. Alejandro de Humboldt y su visión ‘orientalista’ de América
- Jose Alberto Navas Sierra: Humboldt y el ‘Área de Libre Comercio de las Américas (ALCA)’ – Un ejercicio de ‘ciencia humboldtiana
- Miguel Ángel Puig-Samper und Sandra Rebok: Un sabio en la meseta. El viaje de Alejandro de Humboldt a España en 1799
- Ingo Schwarz: Nachruf – Zur Erinnerung an Kurt-R. Biermann
In this work, an approach of paleoclimate reconstruction for tropical East Africa is presented. After giving a short summary of modern climate conditions in the tropics and the East African climate peculiarity, the potential of reconstructing climate from paleolake sediments is discussed. As demonstrated, the hydrologic sensitivity of high-elevated closed-basin lakes in the Central Kenya Rift yields valuable guaranties for the establishment of long-term climate records. Temporal fluctuations of the limnological characteristics saved in the lake sediments are used to define variations in the Quaternary climate history. Based on diatom analyses in radiocarbon- and 40Ar/39Ar-dated sediments, a chronology of paleoecologic fluctuations is developed for the Central Kenya Rift -lakes Nakuru, Elmenteita and Naivasha. At least during the penultimate interglacial (around 140 to 60 kyr BP) and during the last interglacial (around 12 to 4 kyr BP), these lakes experienced several transgression-regression cycles on time intervals of about 11,000 years. Additionally, a long-term trend of lake evolution is found suggesting the general succession from deep freshwater lakes towards more saline waters during the last million years. Using ecologic transfer functions and a simple lake-balance model, the observed paleohydrologic fluctuations are linked to potential precipitation-evaporation changes in the lake basins. Though also tectonic influences on the drainage pattern and the effect of varied seepage are investigated, it can be shown that already a small increase in precipitation of about 30±10 % may have affected the hydrologic budget of the intra-rift lakes within the reconstructed range. The findings of this study help to assess the natural climate variability of East Africa. They furthermore reflect the sensitivity of the Central Kenya Rift -lakes to fluctuations of large-scale climate parameters, such as solar radiation and sea-surface temperatures of the Indian Ocean.
An Oscar M. Lieber (1830-1862) wird bis heute meist im Zusammenhang mit seinem Vater, Francis Lieber, erinnert, der als Publizist einer der einflussreichsten Deutsch-Amerikanern seiner Zeit war. Aber auch Oscar hatte eine bemerkenswerte Karriere in den Vereinigten Staaten. Nach intensiven Studien in Berlin, Göttingen und Freiberg wurde er ein erfolgreicher und produktiver Geologe. Der Aufsatz erinnert insbesondere an die Hilfe, die O. Lieber durch den langjährigen Freund des Vaters, Alexander von Humboldt, erfuhr.An Oscar M. Lieber (1830-1862) wird bis heute meist im Zusammenhang mit seinem Vater, Francis Lieber, erinnert, der als Publizist einer der einflussreichsten Deutsch-Amerikanern seiner Zeit war. Aber auch Oscar hatte eine bemerkenswerte Karriere in den Vereinigten Staaten. Nach intensiven Studien in Berlin, Göttingen und Freiberg wurde er ein erfolgreicher und produktiver Geologe. Der Aufsatz erinnert insbesondere an die Hilfe, die O. Lieber durch den langjährigen Freund des Vaters, Alexander von Humboldt, erfuhr.
Herbert Pieper zum 65. Geburtstag
Inhalt:
- Eberhard Knobloch: Herbert Pieper zum 65. Geburtstag. Ein Rückblick
- Bernd Kölbel, Martin Sauerwein, Katrin Sauerwein, Steffen Kölbel, Cathleen Buckow: Das Fragment des englischen Tagebuches von Alexander von Humboldt
- Ulrike Leitner: Humboldt, Cotta, Ritter. Eine Miszelle über die Arbeit an einer Edition
- Ingo Schwarz: "da ich mich lebhaft für sein Schiksal im Neuen Continent interessire". A. v. Humboldt als Förderer Oscar M. Liebers
- Christian Suckow: Humboldts spanische Option 1830. Eine Nachlese
- Petra Werner: Bemerkungen zu Alexander von Humboldts Russland-Tagebuch
- Herbert Pieper Alexander von Humboldts Wahl in die Akademie der Wissenschaften zu Berlin
- Publikationen von Herbert Pieper [Bibliographie]
The Prussian geologist Leopold von Buch was a lifelong friend of Alexander von Humboldt and had a significant influence on Humboldt’s geological ideas. In a talk, held in Berlin in 1831, which is published here for the first time, von Buch presented the Duria Antiquior of 1830 by the English geologist Henry De La Beche. The Duria Antiquior is widely regarded as the earliest depiction of a scene of prehistoric life from deep time. The print raised new questions about the processes of geohistorical change. The talk reveals that Leopold von Buch was a true scientist of the Romantic Age. His descriptions of geohistorical organismic transformations are taken from pictorial examples of organismic transformation from the classical literature. The talk also illustrates how influential English geologists were for geo-historical reconstructions in Germany.
Inhalt: Kröger, Björn: Remarks on a scene, depicting the primeval world. A talk given by Leopold von Buch in 1831, popularizing the Duria antiquior Roussanova, Elena: Hermann Trautschold und die Ehrung Alexander von Humboldts in Russland Schmuck, Thomas: Tod in den Anden. Ein Brief Francis Halls an Humboldt 1831 und seine historischen und politischen Hintergründe Schnoepf, Markus: Evaluationskriterien für digitale Editionen und die reale Welt Thiemer-Sachse, Ursula: „Wir verbrachten mehr als 24 Stunden, ohne etwas anderes als Schokolade und Limonade zu uns zu nehmen“. Hinweise in Alexander von Humboldts Tagebuchaufzeichnungen zu Fragen der Verpflegung auf der Forschungsreise durch Spanisch-Amerika Schwarz, Ingo: Hanno Beck zum 90. Geburtstag Beck, Hanno: Das literarische Testament Alexander von Humboldts 1799
Inhalt:
Eberhard Knobloch: Der Briefwechsel zwischen Alexander von Humboldt und Charles Lyell: Ein Überblick
Alejandro Cheirif Wolosky: La recepción humboldtiana de Cristóbal Colón
Luiz Estevam O. Fernandes: Political Essay on the Kingdom of New Spain: Humboldt and the history of Mexico
Dominik Erdmann/Christian Thomas: „… zu den wunderlichsten Schlangen der Gelehrsasmkeit zusammengegliedert“. Neue Materialien zu den ‚Kosmos-Vorträgen‘ Alexander von Humboldts, nebst Vorüberlegungen zu deren digitaler Edition
Konstantin Treuber „Warum ich nicht Diorit-Trachyt sagen soll.“ – Ein geologischer Brief Gustav Roses an Alexander von Humboldt
Anja Werner: Alexander von Humboldt’s Footnotes: “Networks of Knowledge” in the Sources of the 1826 Essai politique sur l’île de Cuba
Peter Honigmann: Alexander von Humboldts Journale seiner russisch-sibirischen Reise 1829 [mit einer Einführung von Eberhard Knobloch]
Two of the most controversial issues concerning the late Cenozoic evolution of the Andean orogen are the timing of uplift of the intraorogenic Puna plateau and its eastern border, the Eastern Cordillera, and ensuing changes in climatic and surface-process conditions in the intermontane basins of the NW-Argentine Andes. The Eastern Cordillera separates the internally drained, arid Puna from semi-arid intermontane basins and the humid sectors of the Andean broken foreland and the Subandean fold-and-thrust belt to the east. With elevations between 4,000 and 6,000 m the eastern flanks of the Andes form an efficient orographic barrier with westward-increasing elevation and asymmetric rainfall distribution and amount with respect to easterly moisture-bearing winds. This is mirrored by pronounced gradients in the efficiency of surface processes that erode and re-distribute sediment from the uplifting ranges. Although the overall pattern of deformation and uplift in this sector of the southern central Andes shows an eastward migration of deformation, a well-developed deformation front does not exist and uplift and associated erosion and sedimentary processes are highly disparate in space and time. In addition, periodic deformation within intermontane basins, and continued diachronous foreland uplifts associated with the reactivation of inherited basement structures furthermore make a rigorous assessment of the spatiotemporal uplift patterns difficult.
This thesis focuses on the tectonic evolution of the Eastern Cordillera of NW Argentina, the depositional history of its intermontane sedimentary basins, and the regional topographic evolution of the eastern flank of the Puna Plateau. The intermontane basins of the Eastern Cordillera and the adjacent morphotectonic provinces of the Sierras Pampeanas and the Santa Bárbara System are akin to reverse fault bounded, filled, and partly coalesced sedimentary basins of the Puna Plateau. In contrast to the Puna basins, however, which still form intact morphologic entities, repeated deformation, erosion, and re-filling have impacted the basins in the Eastern Cordillera. This has resulted in a rich stratigraphy of repeated basin fills, but many of these basins have retained vestiges of their early depositional history that may reach back in time when these areas were still part of a contiguous and undeformed foreland basin. Fortunately, these strata also contain abundant volcanic ashes that are not only important horizons to decipher tectono-sedimentary events through U-Pb geochronology and geochemical correlation, but they also represent terrestrial recorders of the hydrogen-isotope composition of ancient meteoric waters that can be compared to the isotopic composition of modern meteoric water. The ash horizons are thus unique recorders of past environmental conditions and lend themselves to tracking the development of rainfall barriers and tectonically forced climate and environmental change through time.
U-Pb zircon geochronology and paleocurrent reconstructions of conglomerate sequences in the Humahuaca Basin of the Eastern Cordillera at 23.5° S suggest that the basin was an integral part of a largely unrestricted depositional system until 4.2 Ma, which subsequently became progressively decoupled from the foreland by range uplifts to the east that forced easterly moisture-bearing winds to precipitate in increasingly eastward locations. Multiple cycles of severed hydrological conditions and drainage re-capture are identified together with these processes that were associated with basin filling and sediment evacuation, respectively. Moreover, systematic relationships among faults, regional unconformities and deformed landforms reveal a general pattern of intra-basin deformation that appears to be linked with basin-internal deformation during or subsequent to episodes of large-scale sediment removal. Some of these observations are supported by variations in the hydrogen stable isotope composition of volcanic glass from the Neogene to Quaternary sedimentary record, which can be related to spatiotemporal changes in topography and associated orographic effects. δDg values in the basin strata reveal two main trends associated with surface uplift in the catchment area between 6.0 and 3.5 Ma and the onset of semiarid conditions in the basin following the attainment of threshold elevations for effective orographic barriers to the east after 3.5 Ma. The disruption of sediment supply from western sources after 4.2 Ma and subsequent hinterland aridification, moreover, emphasize the possibility that these processes were related to lateral orogenic growth of the adjacent Puna Plateau. As a result of the hinterland aridification the regions in the orogen interior have been characterized by an inefficient fluvial system, which in turn has helped maintaining internal drainage conditions, sediment storage, and relief reduction within high-elevation basins.
The diachronous nature of basin formation and impacts on the fluvial system in the adjacent broken foreland is underscored by the results of detailed sediment provenance and paleocurrent analyses, as well as U-Pb zircon geochronology in the Lerma and Metán basins at ca. 25° S. This is particularly demonstrated by the isolated uplift of the Metán range at ~10 Ma, which is more than 50 km away from the presently active orogenic front along the eastern Puna margin and the Eastern Cordillera to the west. At about 5 Ma, Puna-sourced sediments disappear from the foreland record, documenting further range uplifts in the Eastern Cordillera and hydrological isolation of the neighboring Angastaco Basin from the foreland. Finally, during the late Pliocene and Quaternary, deformation has been accommodated across the entire foreland and is still active. To elucidate the interactions between tectonically controlled changes in elevation and their impact on atmospheric circulation processes in this region, this thesis provides additional, temporally well-constrained hydrogen stable isotope results of volcanic glass samples from the broken foreland, including the Angastaco Basin, and other intermontane basins farther south. The results suggest similar elevations of intermontane basins and the foreland sectors prior to ca. 7 Ma. In case of the Angastaco Basin the region was affected by km-scale surface uplift of the basin. A comparison with coeval isotope data collected from sedimentary sequences in the Puna plateau explains rapid shifts in the intermontane δDg record and supports the notion of recurring phases of enhanced deep convection during the Pliocene, and thus climatic conditions during the middle to late Pliocene similar to the present day.
Combined, field-based and isotope geochemical methods used in this study of the NW-Argentine Andes have thus helped to gain insight into the systematics, rate changes, interactions, and temporal characteristics among tectonically controlled deformation patterns, the build-up of topography impacting atmospheric processes, the distribution of rainfall, and resulting surface processes in a tectonically active mountain belt. Ultimately, this information is essential for a better understanding of the style and the rates at which non-collisional mountain belts evolve, including the development orogenic plateaus and their bordering flanks. The results presented in this study emphasize the importance of stable isotope records for paleoaltimetric and paleoenvironmental studies in mountain belts and furnishes important data for a rigorous interpretation of such records.
Quantitative thermodynamic and geochemical modeling is today applied in a variety of geological environments from the petrogenesis of igneous rocks to the oceanic realm. Thermodynamic calculations are used, for example, to get better insight into lithosphere dynamics, to constrain melting processes in crust and mantle as well as to study fluid-rock interaction. The development of thermodynamic databases and computer programs to calculate equilibrium phase diagrams have greatly advanced our ability to model geodynamic processes from subduction to orogenesis. However, a well-known problem is that despite its broad application the use and interpretation of thermodynamic models applied to natural rocks is far from straightforward. For example, chemical disequilibrium and/or unknown rock properties, such as fluid activities, complicate the application of equilibrium thermodynamics.
One major aspect of the publications presented in this Habilitationsschrift are new approaches to unravel dynamic and chemical histories of rocks that include applications to chemically open system behaviour. This approach is especially important in rocks that are affected by element fractionation due to fractional crystallisation and fluid loss during dehydration reactions. Furthermore, chemically open system behaviour has also to be considered for studying fluid-rock interaction processes and for extracting information from compositionally zoned metamorphic minerals. In this Habilitationsschrift several publications are presented where I incorporate such open system behaviour in the forward models by incrementing the calculations and considering changing reacting rock compositions during metamorphism. I apply thermodynamic forward modelling incorporating the effects of element fractionation in a variety of geodynamic and geochemical applications in order to better understand lithosphere dynamics and mass transfer in solid rocks.
In three of the presented publications I combine thermodynamic forward models with trace element calculations in order to enlarge the application of geochemical numerical forward modeling. In these publications a combination of thermodynamic and trace element forward modeling is used to study and quantify processes in metamorphic petrology at spatial scales from µm to km. In the thermodynamic forward models I utilize Gibbs energy minimization to quantify mineralogical changes along a reaction path of a chemically open fluid/rock system. These results are combined with mass balanced trace element calculations to determine the trace element distribution between rock and melt/fluid during the metamorphic evolution. Thus, effects of mineral reactions, fluid-rock interaction and element transport in metamorphic rocks on the trace element and isotopic composition of minerals, rocks and percolating fluids or melts can be predicted.
One of the included publications shows that trace element growth zonations in metamorphic garnet porphyroblasts can be used to get crucial information about the reaction path of the investigated sample. In order to interpret the major and trace element distribution and zoning patterns in terms of the reaction history of the samples, we combined thermodynamic forward models with mass-balance rare earth element calculations. Such combined thermodynamic and mass-balance calculations of the rare earth element distribution among the modelled stable phases yielded characteristic zonation patterns in garnet that closely resemble those in the natural samples. We can show in that paper that garnet growth and trace element incorporation occurred in near thermodynamic equilibrium with matrix phases during subduction and that the rare earth element patterns in garnet exhibit distinct enrichment zones that fingerprint the minerals involved in the garnet-forming reactions.
In two of the presented publications I illustrate the capacities of combined thermodynamic-geochemical modeling based on examples relevant to mass transfer in subduction zones. The first example focuses on fluid-rock interaction in and around a blueschist-facies shear zone in felsic gneisses, where fluid-induced mineral reactions and their effects on boron (B) concentrations and isotopic compositions in white mica are modeled. In the second example, fluid release from a subducted slab and associated transport of B and variations in B concentrations and isotopic compositions in liberated fluids and residual rocks are modeled. I show that, combined with experimental data on elemental partitioning and isotopic fractionation, thermodynamic forward modeling unfolds enormous capacities that are far from exhausted.
In my publications presented in this Habilitationsschrift I compare the modeled results to geochemical data of natural minerals and rocks and demonstrate that the combination of thermodynamic and geochemical models enables quantification of metamorphic processes and insights into element cycling that would have been unattainable so far.
Thus, the contributions to the science community presented in this Habilitatonsschrift concern the fields of petrology, geochemistry, geochronology but also ore geology that all use thermodynamic and geochemical models to solve various problems related to geo-materials.