Search

Zircon U‐Pb‐He double dating (ZDD) provides the opportunity to derive high temperature crystallization ages and low temperature cooling ages from the very same mineral grain, making it especially attractive for zircon provenance studies. We present the combination of in situ detrital zircon U‐Pb‐He double dating and Raman spectroscopy‐based heavy mineral analysis on different tributaries of the Inn river system applying a new grain embedding technique. The Inn river catchment drains a well‐studied complex nappe pile of the Eastern Alps exposing Austroalpine and Penninic crystalline basement rocks. Igneous formations of different emplacement ages, as well as various metasedimentary units, have experienced Alpine and diverse pre‐Alpine metamorphic overprints. This makes the area ideally suited for testing the sensitivity and potential of ZDD for fingerprinting various lithologically contrasting units with contrasting thermal histories. Results demonstrate that both high‐ and low‐temperature age distributions reflect the major sources and thermotectonic pulses, respectively. More specifically, the rocks of the Tauern Window with Miocene (U‐Th)/He ages as well as the Permian metagranitoids from the Tauern and the Err‐Bernina nappe in the uppermost Inn valley are recorded in the downstream Inn sample. The main mass of zircons in the lower Inn, however, derives from the Ötztal and Silvretta crystalline basement rock with Cadomian U‐Pb and Cretaceous (U‐Th)/He ages. The abundance of heavy minerals derived from metamafic formations shows no correlation to the area of such lithologies on the catchments and the different zircon fertility resulted in the overrepresentation of zircon U‐Pb ages from the Variscan igneous suites. Plain Language Summary: The provenance analysis of sediments addresses the question of their origin, which geological formations were the sources of for example, sand bodies. For this so‐called heavy minerals are used that are specific for some rock types and help identify the major lithologies of the source region. The other method is the determination of the age of the detrital zircon crystals that commonly occur in many rock types and sand samples. In our study, we used a relatively new method that determines both the crystallization age and the cooling age in each individual zircon crystal that is highly specific for the source formations of the sediment. Both the heavy mineral analysis and the zircon "double dating" technique were performed on sand samples from the Alpine Inn river to test the reliability of these methods as the catchment of the river is well known and thus it can be used as a reference region. Key Points: Detrital zircon U‐Pb‐He double dating (DD) can accurately specify the sources of sediment—our test performed on well‐studied Alpine catchmentsCombination of DD and Raman‐based heavy mineral analysis applied to modern sands of the Alpine Inn riverComparison of predicted and measured detrital mineralogy and age spectra [ABSTRACT FROM AUTHOR]

The expansion of agricultural frontiers has increased the use of sandy soils as cropping areas; however, the water‐retention capacity (WRC) of the soil is a crucial factor. Thus, fast and accurate methodologies, such as spectroscopy, have gained importance to identify physical‐hydric and other attributes related to the WRC. Some theories indicate the micromorphometry of particles is an important factor in sandy soils. This study (I) investigated the WRC of sandy soils from distinct geologic formations and the influence of particle micromorphometry on the WRC; (II) evaluated the sensitivity of Vis–NIR and MIR spectra to characterise physical‐hydric attributes and particle micromorphometry; and (III) quantified physical‐hydric attributes of sandy soils from their physical attributes, particle micromorphometric indices, and the visible‐near infrared‐mid infrared (Vis–NIR‐MIR) spectra. We determined the values of field capacity (FC), permanent wilting point (PWP), available water (AW), clay, sand, silt, sand fractions, and OM as well as the micromorphometric indices and Vis–NIR and MIR reflectance of 29 sandy soil profiles. Soil attributes were correlated with each other and with the Vis–NIR and MIR spectra to understand their relationship with the WRC. The correlation and the principal component analyses (PCA) were performed to understand the relationship between Vis–NIR and MIR spectra and sand grain micromorphometry. Mathematical models were developed to estimate FC, PWP, and AW using soil attributes, micromorphometry, Vis–NIR, and MIR as predictor variables. Roughness of sand particle greatly influenced the WRC of sandy soils. The MIR region showed high sensitivity to identify different WRC patterns and particle micromorphometry in sandy soils. The Vis–NIR and MIR spectra presented high accuracy to predict FC and PWP of sandy soils. The mathematical models that used soil attributes + micromorphometry presented excellent calibration parameters; however, they did not show accuracy in the validation set. Highlights: The influence of particle roughness on water retention of sandy soils was proven.Roughness had a greater influence on water retention than texture proportions for highly sandy soils.MIR spectra correlate strongly with the roughness of the very fine sand fraction.MIR spectra and roughness can estimate sandy soils water retention with high accuracy. [ABSTRACT FROM AUTHOR]