Igor M Villa

An accurate record of preindustrial (pre-1900 CE) sea level is necessary to contextualize modern global mean sea level (GMSL) rise with respect to natural variability. Precisely dated phreatic overgrowths on speleothems (POS) provide detailed rates of Late Holocene sea-level rise in Mallorca. Statistical analysis indicates that sea level rose locally by 0.12 to 0.31 m (95% confidence) from 3.26 to 2.84 thousand years (ka) ago (2σ) and remained within 0.08 m (95% confidence) of preindustrial levels from 2.84 ka to 1900 CE. This sea-level history is consistent with glacial isostatic adjustment models adopting relatively weak upper mantle viscosities of ~10 20 Pa s. There is virtual certainty (>0.999 probability) that the average GMSL rise since 1900 CE has exceeded even the high average rate of sea-level rise between 3.26 and 2.84 ka inferred from the POS record. We conclude that modern GMSL rise is anomalous relative to any natural variability in ice volumes over the past 4000 years.

<p>The Vinschgau Shear Zone (VSZ) is an E-W striking ductile shear zone developed within the central-eastern Austroalpine domain. Along the VSZ the Ötztal-Stubai nappe with an amphibolite facies Alpine metamorphism overthrusted the Campo nappe (and respectively the Engadine Dolomites) characterized by low-to-medium metamorphic conditions (Schmid and Haas, 1989). In the eastern part the shear zone involves also the Texel Unit at the base of the Ötztal nappe. Foliation gently dips (20°-30°) northward and lineation constantly strikes E-W, with kinematic indicators that point to a top-to-NW sense of shear. The VSZ, deepening to the E, developed mostly under amphibolite to greenschist-facies conditions. A remarkable variation in finite strain along its length can be observed: lenses of protomylonites are bounded by deeply sheared ultramylonites, mylonites and phyllonites, these occurring in the western part of the VSZ.</p><p>In order to fully assess the evolution of the VSZ a multidisciplinary approach based on structural and petrochronological analyses has been carried out on three representative transects of the shear zone from W to E: Eyrs, Schlanders and Juval transects.</p><p>Our fieldwork based analyses suggest that the dip of mylonitic foliation increases from W to E and the lineation dips towards the W in Schlanders and Juval, whereas towards the E in Eyrs, probably due to a folding event related to Cenozoic shortening (Pomella et al., 2016).</p><p>Chemical and microstructural analyses suggest that deformation temperatures of 350-400 °C have been reached during shearing, as testified by Ti content in biotite and by bulging and subgrain rotation as dominant recrystallization mechanisms in quartz.</p><p>Timing of deformation along the VSZ has been constrained through <sup>40</sup>Ar/<sup>39</sup>Ar dating of syn-shearing micas confirming previous geochronological data of Thöni, 1981, which reveal a Late Cretaceous age of the VSZ mylonites. A systematic younging trend of deformation towards the central part of the shear zone has been observed in the studied area. Vorticity analyses, both through shear bands and rigid porphyroclasts methods, show a clear decrease in simple shear component correlated to the younging direction of mica ages (i.e. towards the core of the shear zone). This evolution is clearly consistent with Type 2 evolution of Fossen and Cavalcante (2017), where strain localizes into the core of the shear zone during deformation.</p><p>Our data confirm the age of the VSZ only supposed on the base of indirect observations  and demonstrate that the Austroalpine domain was severely affected by W-NW verging thrust stacking much time before the Adria-Europe continental collision.</p><p> </p><p><em>References</em></p><p>Fossen, H. & Cavalcante, G.C.G., (2017) - <em>Shear zones–A review</em>. Earth-Science Reviews, <strong>171</strong>, 434-455.</p><p>Pomella, H., Flöss, D., Speckbacher, R., Tropper, P., & Fügenschuh, B. (2016) - <em>The western end of the Eoalpine High‐Pressure Belt (Texel unit, South Tyrol/Italy).</em> Terra Nova, <strong>28(1)</strong>, 60-69.</p><p>Schmid, S.M., & Haas, R. (1989) - <em>Transition from near‐surface thrusting to Intrabasement Decollement, Schlinig Thrust, eastern Alps</em>. Tectonics, <strong>8(4)</strong>, 697-718.</p><p>Thöni, M. (1981):<em> Degree and evolution of the Alpine metamorphism in the Austroalpine unit W of the Hohe </em><em>Tauern in the light of K/Ar and Rb/Sr age determinations on micas. - </em>Jb. Geol. B.A. 124, 1: 111-174.</p>

ABSTRACTThe Las Canadas Caldera corresponds to a volcanic caldera formed after a long period of explosive activity. The structural and lithological variations which can be observed in the caldera wall make clear the complexity of the original Las Canadas Edifice in which different eruptive centres existed. The stratigraphic and structural reconstruction of the Las Canadas Caldera indicates that the Diego Hernández wall, located at the eastern side of the caldera wall, comprises the youngest pre‐caldera deposits. Determination of their K‐Ar ages has provided the maximum age for the formation of the Las Canadas caldera. The results are internally consistent with stratigraphic relationships and allow two pre‐caldera volcanic cycles in the Diego Hernández wall to be differentiated in accordance with geological evidence. The first cycle shows imprecise age limits. The second cycle ranges from 0.35 to 0.17 Ma. This upper pre‐caldera age suggests that the Las Canadas caldera and the Teide‐...

... in sequences, because with the ages obtained, the evolution of the Diego Hernandez Formation is ... Giiimar valley) to find correlation levels between these areas and Diego Hernández Formation to ... Fuster, JM, Araña, V., Brandie, JL, Alonso, U. and Aparicio, A. (1968) Geología y ...

The Southern Tuscanv-Norrhern Latium area has been affected by a complex geological evolution during Neogene times. Starting from Miocene, several subsidence episodes, alternated with periods of differential uplifting, brought to the development and closure of some marine and continental basins. Since Pliocene, an intense and widespread magmatic activity .has also interested this region, characterized by a space-time eastward migration of the magmatic centers and by a strong variation in time of the magma composition. Very high heat flow values are observed over the whole area, which represents one of the most interesting geothermal Italian regions. In this paper we present an attempt to combine the stratigraphical, geochronological, volcanological and geophyslcal data in an unifying picture of the regional structural evolution, and of the relationships between Neogene sedimentary basins, subsidence and uplift phases, and rnagmatic activity. New biostratigraphic datings of the Pliocene successions have been performed, together with several radiometric, K/Ar and 39Ar/40Ar, datings of Plio-Pleistocene volcanic, from samples of outcropping and subsurface sequences. The geothermal wells drilled by ENEL, and by J.V. AGIP-ENEL, integrated by results from surface survey’s, have permitted to define the present thickness of Pliocene sediments, the geometry of the bottom surface of the Plistocene volcanic cover, and the map of the present altitude of Plio-Pleistocene marine sediments reflecting the sum of the total vertical movements. The chemical composition of Pleistocene volcanic complexes of the Northern Roman Magmatic Province has been investigated, tryng to delineate its temporal evolution. The subsurface geoogy of the area has been finaly analyzed in the light of drilling results and of gravimetric and thermal data. Since Pliocene, a very intense extensional tectonics affects The investigated area. Two Pliocene sedimentary cycles can be distinguished, leading to the deposition of sedimentary successions up to two thousands meters thick. Subsidence movements appear more intense in a relatively narrow, NW-SE trending belt close to the Apennine range, while the Tyrrhenian side suffers a less developed subsidence witnessed by the deposition of several discontinuous, not very thick sedimentary piles. Pliocene magmatic activity sets up just on the Tyrrhenian border, with the emplacement of several intrusive bodies and the extrusion of prevalently acid crustal anatectic magmas and of minor subcrustal mafic melts. We suggest taht the different structure presented by the western side of the investigated area could reflect a primary role of a diffuse intrusive process in this area. Pliocene sedimentation stops in the whole area around 2 Ma b.p.; marine sedimentation resumes during lower Pleistocene, inside more eastern basins. The associated volcanic axis (defined by the Radicofani, Torre Alfina, Monti Cimini alignment) assumes a more eastern position than the preceding one, and is characterized by orenditic transitional to potassic magmas. During Pleistocene, the regional stress field undergoes a strong variation, connected to the opening of the Marsili basin in the Southern Tyrrhenian Sea. Positive vertical movements seem to prevail since Middle-Upper Pleistocene, probably linked to the strong isostatic uplift of the Apennine chain. The present geometry shown by the Neogene sediments mainly reflects this uplift phase. The potassic vo1canism of Roman Magmatic Province starts in the wholele region (and probably also further South) around 0.6 Ma b.p., showing a strict relationship with the new prevailing tectonic regime, this magmatism being distributed along the disengaging zone between the uplifting chain and the subsiding Tyrrhenian basins. A further pulse of magmatic activity occurs around 0.4-0.3 Ma b.p., wlth a very intense volcanicity affecting all the main volcanic complexes, accompanied by a maximum in the compositional spreading o f the erupted products. The time variations of magma composition and the tectonic evolution of the area, shoving a progressive deepening of magmatic sources associated to a general decreasing of extensional tectonics, seem to be strongly related. In this picture, the present heat flow anomaly would represent the residual of the thermal anomaly associated with the Neogene extensional setting

Abstract In solid-state physics and materials science Fick's Law diffusion is a well-established process. In Earth Sciences, laboratory experiments on garnet, olivine and other anhydrous minerals do document the intra-grain element concentration gradients that follow the functional form required by Fick's Law. Natural gradients in minerals have rarely been analyzed with the necessary spatial resolution. Reports of actual observations of diffusion profiles of element concentrations are rare in the literature, and diffusion profiles of isotope ratios in minerals used for geochronology are absent. An in-depth re-examination of recent and older literature suggests that isotope transport in minerals is instead often dominated by fluid-mediated retrogression reactions. Imaging microtextures by cathodoluminescence or back-scattered electron maps provides ubiquitous evidence of patchy or dendritic replacement structures, which correspond to multiple growth stages, in zircon, monazite, muscovite, biotite, K-feldspar, etc. The U–Pb, K–Ar and Rb–Sr systems in these partly retrogressed minerals show isotopic inheritance (that survived the retrograde reactions at least in part) in close correspondence with the petrologic relicts. Depending on the relative rates of the petrological processes relevant for isotope transport, geochronometers can be grouped in two classes: Class I (thermochronometers) are those for which the diffusivity of a given radiogenic isotope is faster than the rate of dissolution and/or reprecipitation, and Class II (hygrochronometers) are those for which aqueous dissolution/reprecipitation is the faster process. All of the abovementioned geochronometers, for which patchy/dendritic textures formed by diachronous mineral generations and isotopic inheritance were observed, must be assigned to Class II. Class II samples in petrologic equilibrium can (but need not) record purely thermal diffusion of daughter isotopes. The isotope record of Class II minerals in petrologic disequilibrium, being controlled by inheritance and retrogression reactions, depends chiefly on the reaction-promoting factors, water activity and strain. The dependence of Class II mineral ages on thermal diffusion is subordinate and never unique.

The boundary between the Austroalpine Err nappe and the Penninic Platta unit represents part of a Late Cretaceous continent-ocean suture preserved in the highest stockwerk of the Tertiary Alpine orogen. Subduction and nappe stacking (D1) and subsequent extensional uplift (D2) along part of this suture are dated with the K-Ar method on two generations of syn-kinematic white mica in the Err nappe and with Ar-Ar step-heating of syn- to post-kinematic riebeckitic amphiboles in the Platta nappe. The first generation of white micas associated with isoclinal folds and W-directed mylonitic thrusting along nappe contacts yields a 76 to 89 Ma age range, whereas the second generation of white micas that grew during tight folding and top-to-the-E extensional D2 shearing yields 67 to 80 Ma ages. The K-Ar white mica ages are interpreted as ages of formation at the approximately 300°C temperature of lower green-schist facies regional metamorphism in the southern part of the Err nappe. The two amphibole samples from the Platta nappe yield 69 and 73 Ma Ar-Ar ages, interpreted as syn-D2 formational ages. The Si-content of the white micas in chlorite-K-feldspar-quartz-bearing meta-radiolarites in the southern part of the Err nappe indicate a pressure decrease from D1 to D2 deformation, probably accompanied by an increase in temperature. This can be related to D2 extensional uplift accommodated along reactivated D1 nappe contacts in the footwall of the Julier-Bernina nappe. When combined with stratigraphic evidence, the radiometric ages and deformation-crystallization relations indicate clockwise P-T paths for the Err, Platta, and Margna nappes: Suturing of the Austroalpine continental and Liguro-Piemontese oceanic crust began with near surface thrusting and flysch sedimentation between 88 and 100 Ma and culminated with D1 folding and nappe stacking under high P/T greenschist facies conditions sometime during the period 80 to 88 Ma. The unroofing of this suture was a multi-stage process involving Late Cretaceous D2 extension under greenschist facies conditions, Early Tertiary D3 thrusting under lower anchizonal conditions, and mid-Tertiary D4 normal faulting above the uplifting Lepontine dome.</p

We present 39Ar-40Ar dating of phengite, muscovite and paragonite of samples from the HP Voltri massif (Western Alps) and from the conglomerates of the Tertiary molasses which overlie the metamorphic basement. The phengite bearing rocks analysed display peak eclogitic and blueschist facies parageneses, locally showing complex greenschist - facies replacement textures. 39Ar-40Ar dating of white micas yielded Eocene ages interpreted as the time of different metamorphic equilibrations. In particular, high-Si phengites from eclogite clasts record a ca. 49 Ma age for the eclogite peak and ca. 43 Ma for the blueschist retrogression; phengites from a blueschist basement sample record a ca. 40 Ma for the metamorphic peak; low-Si muscovite from a metasediment dates the formation of the greenschist paragenesis at ca. 33 Ma. The internal discordance of age spectra is proportional to the chemical complexity of the micas. Our data document that the rock samples analyzed reached peak HP conditions at different times over a time - span of ca. 10 Ma. The subduction to peak blueschist conditions is in fact still going on during the exhumation of higher-pressure, eclogite-facies rocks. Our results therefore fit a tectonic model with different ophiolitic slices subducted at different moments, over a time span ranging from Lower Eocene until the Eocene-Oligocene boundary. This implies that the subduction and exhumation processes occurred simultaneously, allowing the uprising HP-rocks to escape termal reequilibration. Our data require a decoupling of exhumation from erosion: exhumation was largely accomplished before significant erosion of the wedge. Initially, it was likely driven by the buoyancy effect of antigorite serpentinites; subsequently it may have been associated with the development of blueschist shear zones. Fast exhumation was not accompanied by a high uplift of the mountain chain, whose erosion and input into the sedimentary basin occurred more than 10 Ma later.

<p>Pseudotachylytes are solidified frictional melts produced by seismic fault slip. Being melts that solidified in seconds or minutes after the seismic slip event, they have always been considered a very favourable tool to date brittle deformation. However, since all pseudotachylytes are composed of inherited clasts, melt-derived matrix and (quite often) also alteration products, it is necessary to discriminate the Ar contribution of these three reservoirs to obtain meaningful ages. This can be done by analyzing Ca/K and Cl/K signatures provided by Ar systematics. Furthermore, microstructural analysis and microCT allow quantifying the clast-to-pseudotachylyte matrix ratios for each sample, and XRPD allows detecting potential alteration phases. Here we present the results of step-heating <sup>40</sup>Ar/<sup>39</sup>Ar analyses performed on pseudotachylytes of the Trois Villes Fault and the Quart Fault, which crop out in a region of the Western Alps (Aosta Valley) affected by three different post-metamorphic brittle deformation phases: D1 characterized by NW-SW extension, D2 with NE-SW extension, and D3 showing N-S extension. The relative chronology of these deformation phases is based on consistent cross-cutting relationships. D1 ages of 29–32 Ma have been inferred from syn-kinematic magmatic dikes and hydrothermal veins. However, no absolute ages were so far available for D2 and D3, as direct radiometric dating of fault rocks has never been performed before in the area. Our results are consistent with the relative chronology and greatly improve our understanding of the tectonics of this area.</p>

The Bressanone (Brixen) pluton, cropping out at the culmination of the Southalpine indenter between the North Giudicarie and the Pustertal-Gailtal faults, is mainly composed of Permian granodiorite to granite, with minor gabbros and diorites in its southern part. New U–Pb SHRIMP zircon ages reveal two distinct crystallization episodes at 289.7 ± 3.2 and 280 ± 2.2 Ma, respectively. The pluton is affected by a hydrothermal potassic to sodic + Cu metasomatic alteration, which has long been ascribed to a late phase of the Permian magmatism. In contrast with this hypothesis, we report new <sup>39</sup>Ar–<sup>40</sup>Ar data for different generations of metasomatic K-feldspar, which indicate formation ages between 35.3 ± 0.3 and 27.8 ± 0.5 Ma. This interval overlaps with the ages of the widespread 'Periadriatic' calc-alkaline magmatism, which extends from the Western to the Eastern Alps straddling the Periadriatic Fault System. The observed hydrothermalism has geochemical characteristics compatible with those of the coeval calc-alkaline Periadriatic magmatism. These data altogether suggest the release of fluids from a hidden intrusion during the main stage of the Alpine orogenic magmatism. Our results provide the first evidence of Oligocene magmatic activity in the Southern Alps east of the Giudicarie Line, bridging the gap between the western-central and eastern Alpine magmatic plutons. A fairly continuous Oligocene magmatic belt straddling the Periadriatic Fault System is consistent with a triggering of the magmatism by slab steepening or slab break-off, either of which are considered to be an essential driver for the Miocene lithospheric rearrangement in the Eastern Alps. Our finding is particularly relevant given that the outcropping area of the Bressanone pluton is centred above the imaged subducting lithosphere gap that separates the Western-Central and the Eastern Alps, hence at a location where mantle upwelling should have been easier although no relevant magmatism was found to date.

The IUPAC–IUGS joint Task Group “Isotopes in Geosciences” (TGIG) has evaluated the published literature on the half-lives of six long-lived, geologically relevant radioactive nuclides. Where conflicting literature estimates are present, it is necessary to first identify any systematic bias in accordance with metrological traceability and to exclude the biased estimates from further consideration. The TGIG recommends three robust half-life estimates: 49.61 ± 0.16 Ga for 87Rb, corresponding to a decay constant λ(87Rb) = (1.3972 ± 0.0045) × 10−11 a−1; 106.25 ± 0.38 Ga for 147Sm, and a corresponding decay constant λ(147Sm) = (6.524 ± 0.024) × 10−12 a−1; 4.4683 ± 0.0096 Ga for 238U, i.e. a decay constant λ(238U) = (1.55125 ± 0.00333) × 10−10 a−1. All cited uncertainties have a coverage factor k = 2. For other radionuclides of Sm and U, no unambiguous consensus value can be endorsed at present by TGIG, which limits its evaluation to a status report highlighting unaccounted-for potential s...

The sequence stratigraphic framework and a summary of the fossil fauna of the upper Miocene portion of the Pisco Formation exposed along the western side of the Ica River (southern Peru) is presented through a new geological map encompassing an area of about 200 km 2 and detailed chronostratigraphic analyses. Extensive field mapping and sedimentological study of outcrop sections have shown that the Pisco Formation is a cyclical sediment unit composed of at least three fining-upward, unconformity-bounded depositional sequences, designated P0, P1, and P2 from oldest to youngest. In the study area, these sequences progressively onlap a composite basal unconformity from southwest to northeast. Integration of biostratigraphic and tephrochronologic age determinations constrains the ages of the three Pisco sequences within the study area. Based on the age of surrounding sediments, a conservative estimate of the age of P0 suggests deposition of these strata between 17.99 ± 0.10 Ma and 9.00 ...

Abstract Medieval pavements composed of lead-glazed tiles decorated with a variety of techniques continue to inspire questions about the organisation of glaze manufacture, and the supply and origin of lead materials. The tiles analysed in this study are from Suscinio I (a 13th-century pavement) and Suscinio II (a 14th-century pavement), at the Château of Suscinio in Brittany, and also from the 14th-century pavement at the fortified manor house in Brain-sur-Allonnes, Anjou. Lead isotope analysis (LIA) was used to examine samples from 44 lead-glazed tiles, 29 of which are transparent, while 15 are tin-opacified (an exogenous technique in these regions during this period). Five out of the six LIA groups thus identified favour site-specific supply networks, while results for the remaining group, LIA5, indicate a multi-site supply network. After combining LIA results with archaeological and historical data, the most likely provenance for the lead materials in LIA5 is Derbyshire, in the British Isles. Both the importation of ready-to-use glazing mixtures and the use of lead from neighbouring mines can now therefore be discounted as plausible hypotheses for the production of the tin-opacified lead-glaze tiles analysed in this study.

A peralkaline microgranitic enclave was found enclosed in the Green Tuff ignimbrite on Pantelleria island. This enclave represents the intrusive equivalent of pantelleritic lava flows. Its K­ Na-feldspar has been dated by 39ArAOAr and gave a plateau age of 517 ± 19 ka. This age is considerably older than all outcropping rocks dated so far ( < 324 ka), and requires to shift the onset of magmatc activity on Pantelleria back in time.

The term alabaster is often applied only to compact, translucent gypsum, but sometimes it also denotes a variety of decorative rocks consisting essentially of calcium carbonate. Calcareous alabasters, often petrographically classified as travertines, were quarried in several provinces of the Roman Empire and widely used for architectural elements and small decorative objects. In spite of their considerable importance as ornamental stones, and their wide distribution, very little is known about their origin, and their positive identification often remains very difficult. This is due to their variability of color and fabric, also within the same species, and to a lack of specific studies, especially of archaeometric characterisation. Hence our analyses - minero-petrographical (by XRD and OM on thin section) and geochemical (Sr isotopes by mass spectrometry, and chemical quantitative analysis by XRF) - of two important Italian alabasters, those of Iano di Montaione (Florence) and of Ca...

Abstract This paper represents the first systematic Pb isotope investigation of Italian Medieval coins and aims to provide new parameters for a general historical interpretation of coin production and circulation in Medieval Europe. We collected more than one hundred specimens, minted in a period between 9th − 14th centuries AD and coming mostly from archaeological sites of Tuscany. Here we report the results on the oldest group of (44) coins, dated between the end of the 9th and 11th centuries. All coins where previously characterized with handheld X-ray fluorescence (pXRF) analysis and lead isotope composition (PbIC) was performed using an MC-ICP-Mass Spectrometer. The Carolingian coins have PbIC compatible with Melle silver district; the few Carolingian coins possibly minted in Italy (Venice and Milan) are also compatible with ore districts such as Melle and Harz Mountains. Coins in the names of Italian rulers (9th-10th century) from Lucca, Pavia and other uncertain mints show PbIC compatible with Melle, Black Forest and the Harz Mountains as well. A quite similar pattern applies to coins in the names of Otto I-III and Conrad II (10th-11th century) from Lucca and Pavia mints, although they show a better overlap with the Harz Mountains. The vast majority of early medieval coins issued by the Italian mints investigated in the present paper show isotope compositions that do not match with silver (lead-copper) mines from the Colline Metallifere district of southern Tuscany, notwithstanding their exploitation in the considered period is suggested by many settlements located near mining sites.

Lead isotope compositions were determined for 18 metal objects from the archaeological site of Sant’Imbenia, NW Sardinia, dating to the end of the ninth century BCE onwards. The provenance of some objects is unambiguously traced to SW Sardinia; other objects could derive either from central Sardinia or the Iberian coastal ranges. The variety of the provenances attests to a wide trade network that spanned the entire island of Sardinia and extended to the Iberian sites.

The Bela ophiolite of Pakistan contains a complete ophiolite‐accretionary wedge‐trench sequence emplaced onto the Indian continental margin during the northward drift of India‐Seychelles over the active Réunion hotspot. A structurally higher ophiolite overlies an accretionary prism, which is thrust over a foreland basin. Shear‐sense determinations in peridotite mylonites in the ophiolite footwall and imbrication structures in the underlying accretionary wedge indicate an ESE emplacement. Sedimentary rocks in the accretionary wedge indicate Aptian‐Albian pillow lavas, initially deep water conditions, and increasing influence from the continent until the Maastrichtian. The ophiolite emplacement was predated and accompanied by Fe‐tholeiitic and alkaline magmatism related to the Réunion hotspot and continuous incorporation of trench sediments into the accretionary wedge. 39Ar/40Ar dating shows that the ophiolite formed around 70 Ma. Intraoceanic subduction initiated between 70 and 65 Ma...

The mass balance of molybdenum (Mo) was studied in the Strengbach catchment. Monitoring of rainfall, vegetation, and soil characteristics in this 0.8 km2 catchment was started decades ago. We present Mo concentrations and isotope compositions of about 60 samples including bedrock types, perennial springs, soil profiles, roots and leaves, and the outflowing brook. Both stream waters and bedrocks have Mo concentrations at least one order of magnitude lower than global averages. The Mo isotope composition of topsoils, foliage, litter, and roots is rather homogeneous. Net biological fractionation is thus subordinate to differences in the Mo sources. Efficient Mo recycling from organic litter to plants keeps Mo bioavailable. The Mo and Sr isotope data, are used to identify the source(s) of Mo and Sr and their (transient) storage within the catchment. The resulting best model identifies rock weathering and seawater derived aerosol as the principal Mo sources. Moreover, soil in the Strengbach catchment has reached steady state for Mo (the time constant to achieve soil steady state is calculated to be in in the order of 50 years) where the Mo isotope compositions of fluxes to and from the catchments soil are identical