Search

To date, the most complete paleolake‐level reconstructions for the late Pleistocene water bodies that once occupied the Dead Sea depression have been based on the combination of dating of lake sediments and terrestrial materials. However, despite these major accomplishments, there is still limited spatial control regarding the water levels, suggesting some degree of uncertainty concerning the magnitude and rate of lake‐level changes. Here, we re‐examine the late Pleistocene lake‐level changes in the Dead Sea during the transition from paleolake Lisan to the present‐day Dead Sea. We rely on systematic dating of fossil stromatolites including 84 radiocarbon and 15 U‐series ages, stable‐isotope measurements, paleobiology, high‐resolution topography, and numerical modeling to assess lake‐level changes. Our results indicate that the highstand of paleolake Lisan was of shorter duration and the transition between Lake Lisan and the Dead Sea occurred at least 5 Kyrs earlier than previously indicated. By refining the timeline and accuracy of lake‐level positions during the transition paleolake Lisan—Dead Sea, our study offers new insights into the regional and local paleo‐climatic conditions during the last glacial period in this region. Plain Language Summary: Index points, reflecting the unique position of the water levels in space and time, have been broadly used in marine realms to reconstruct past sea‐level changes. Here we study lake‐level variations using index points based on geomorphic and biological markers collected along the western and eastern coasts of the Dead Sea. Previous studies indicate that during the last glacial period (20–30 ka), the Dead Sea depression was filled by paleolake Lisan, which lasted 10 Kyrs. As it dried, dozens of paleo‐shorelines remained etched in the landscape. Lake level index points estimated from 99 radiometric ages in these paleo‐shorelines suggest that Lisan's highstand was shorter and the transition to the Dead Sea occurred 5 Kyrs earlier than previously thought. These novel results suggest an initial and wet period followed by drier conditions, altering the regional paleo‐climatic narrative during the last glacial period. Key Points: Lake paleo‐shorelines and fossil stromatolites are used to reconstruct lake‐level changes during the transition paleolake Lisan‐Dead SeaFossil stromatolites were dated using radiocarbon and U‐series applying temporal and vertical correctionsThe transition between paleolake Lisan and the Dead Sea occurred ∼5 Kyrs earlier than estimated by previous reconstructions [ABSTRACT FROM AUTHOR]

Intermontane basins are illuminating stratigraphic archives of uplift, denudation and environmental conditions within the heart of actively growing mountain ranges. Commonly, however, it is difficult to determine from the sedimentary record of an individual basin whether basin formation, aggradation and dissection were controlled primarily by climatic, tectonic or lithological changes and whether these drivers were local or regional in nature. By comparing the onset of deposition, sediment-accumulation rates, incision, deformation, changes in fluvial connectivity and sediment provenance in two interrelated intermontane basins, we can identify diverse controls on basin evolution. Here, we focus on the Casa Grande basin and the adjacent Humahuaca basin along the eastern margin of the Puna Plateau in northwest Argentina. Underpinning this analysis is the robust temporal framework provided by U-Pb geochronology of multiple volcanic ashes and our new magnetostratigraphical record in the Humahuaca basin. Between 3.8 and 0.8 Ma, ~120 m of fluvial and lacustrine sediments accumulated in the Casa Grande basin as the rate of uplift of the Sierra Alta, the bounding range to its east, outpaced fluvial incision by the Río Yacoraite, which presently flows eastward across the range into the Humahuaca basin. Detrital zircon provenance analysis indicates a progressive loss of fluvial connectivity from the Casa Grande basin to the downstream Humahuaca basin between 3 and 2.1 Ma, resulting in the isolation of the Casa Grande basin from 2.1 Ma to

The tectonically active South American margin is characterized by the accumulation of deformation contributing to uplift of the Andean forearc at millennial time scales. However, the mechanisms responsible for permanent coastal uplift are debated, mainly because methodologically consistent, continental‐scale analyses of uplifted terraces have not yet been carried out for South America. Uplifted marine terraces are generally used to infer permanent coastal deformation and uplift; we used almost 2,000 measurements of last‐interglacial marine terraces to calculate an uplift‐rate signal on which we performed a wavelength analysis. The same spectral analysis was applied to tectonic and subduction parameters associated with accumulation of permanent deformation to detect possible links with the uplift‐rate signal. The uplift‐rate signal displays a constant background‐uplift rate along the margin, perturbed by changes at variable wavelengths. Similarities between its wavelength spectrum and the spectra of tectonic parameters suggest potential correlations pointing toward underlying processes. For example, crustal faulting is mainly responsible for short‐wavelength deformation; intermediate‐wavelength to long‐wavelength tectonic features indicate various extents of locked areas on the megathrust that relate to its long‐term seismotectonic segmentation. We suggest that moderate, long‐term background uplift is caused by major, deep earthquakes near the Moho, although records of such events are sparse. Due to their disparate occurrence, we infer accumulation of permanent deformation over millennial time scales through multiple, distinct uplift phases that are spatially and temporally distributed. Our study highlights the application and utility of a signal‐analysis approach to elucidate the mechanisms driving surface deformation in subduction zones at a continental scale. Key Points: Our novel signal‐analysis approach elucidates the mechanisms driving surface deformation in subduction zones at a continental scaleSpectral similarities suggest correlations of uplift rate with crustal faulting and the seismotectonic segmentation of the megathrustContinuous background uplift might be caused by major, domain‐C earthquakes through spatially and temporally distinct phases of uplift [ABSTRACT FROM AUTHOR]