Precise and high-resolution chronologies of continental sedimentary records (e.g., lacustrine and cave deposits) are instrumental for establishing Quaternary climatic pattern on the continents and for comparison to marine and ice core records of climate change. Radiocarbon is the major dating method for establishing Holocene and late-glacial chronologies, yet its use often requires determination of the reservoir age, and beyond ca. 24 ka cal. B.P., the calibration curve to calendar years is not well established. Thus, beyond the youngest portion of the last Glacial period, U-Th dating of carbonates becomes the major means in obtaining high-resolution chronologies. However, these age determinations are hampered by contamination of the samples with detrital U and Th and by the presence of aqueous Th. Here we summarize the approaches used to address the problems in U-Th and radiocarbon dating of the late Pleistocene and Holocene sedimentary records of the Dead Sea basin. This mainly includes solutions for the problem of detrital U and Th and aqueous (initial) Th in the Lisan carbonates and the evaluation of “reservoir ages” in the determination of carbonate radiocarbon ages. The calendar U-Th and calibrated radiocarbon ages are used for establishing the environmental (climate and seismological) chronology of the region (e.g., reconstruction of a high-resolution lake level curve and correlation with global climatic records), for paleomagnetic reconstruction (e.g., the documentation of secular variations and geomagnetic excursions such as the Laschamp Event ca. 40 ka cal B.P.), and extending the calibration of the radiocarbon time scale.

We dedicate this manuscript to Dr. Cipora Klein, who studied the historic levels of the Dead Sea . This paper reviews the research and lake level reconstruction of the late Pleistocene and Holocene lakes in the Dead Sea basin. Lake Lisan and the Dead Sea occupied the Dead Sea basin during the past 70 k.y., and responded to and amplified regional climatological variations in the Eastern Mediterranean. Overall, the lake level history is correlative with global climate patterns. The Lake Lisan high levels correspond to the last Glacial period (marine isotope stages 2–4); its dramatic level drop to the transition to the Holocene, and the Dead Sea low stands to the current interglacial period. The Lisan level record also appears to show relationships to millennial events in Greenland ice and deep-sea cores. The paper describes the methodologies applied to identify indicators of lake level elevations and the determination of their ages. It is divided to (1) the early research history (mainly commencing at the nineteenth century) in the Dead Sea basin; (2) the early efforts of lake level curve reconstructions; and (3) the most recent studies that yield well-dated, high resolution lake level chronologies.

We have studied the magnetic properties of wet and dry late Pleistocene Lake Lisan sediments and the Holocene Dead Sea sediments. Our initial prediction was that the properties of both would be quite similar, because they have similar source and lake conditions, unless diagenetic change had occurred. Rock magnetic and paleomagnetic experiments revealed three stages of magnetization acquisition. Our findings suggest two magnetic carriers in the Holocene Dead Sea and wet Lisan sediments: titanomagnetite and greigite. The titanomagnetite grains are detrital and carry a detrital remanent magnetization (DRM), whereas the greigite is diagenetic in origin and carries a chemical remanent magnetization (CRM) that dominates the total natural remanent magnetization (NRM) of Holocene Dead Sea and wet Lisan sediments. The magnetization of dry Lisan sediments is a DRM and resides in multidomain (MD) grains. We propose that magnetic properties of the Lisan Formation and Holocene Dead Sea sediments can be explained by a model that incorporates dissolution, precipitation, and alteration of magnetic carriers. At the time of deposition, titanomagnetite grains of varying size were deposited in Lake Lisan and the Holocene Dead Sea, recording the geomagnetic field via a primary DRM. Sedimentation was followed by partial or complete dissolution of titanomagnetite in anoxic lake bottom conditions. As the kinetics of dissolution depends upon surface area, the single-domain (SD) grains dissolved faster, leaving only the larger pseudo-single domain (PSD) and MD grains. Titanomagnetite dissolution occurred simultaneously with precipitation of greigite in anoxic, sulfate-reducing conditions probably related to bacterial degradation of organic matter. This process added a secondary CRM that overwhelmed the DRM and the primary geomagnetic record. Later, when the level of Lake Lisan dropped, these sediments were exposed to air. At this time, the greigite was oxidized, removing the CRM from the system and leaving only the original detrital PSD and MD titanomagnetite grains as the dominant DRM carriers. Presently, wet Lisan sediments have not been completely altered and therefore contain secondary greigite preserved by the original formation water that carries a secondary CRM. Thus, the magnetization in the Holocene Dead Sea and the wet Lisan magnetic record cannot be considered as an accurate, reliable geomagnetic record, while magnetization of dry Lisan sediments is a primary DRM.

This paper summarizes the research efforts devoted over the years to the understanding of the origin and evolution of brines in the Dead Sea basin. These brines are characterized by a unique Ca-Chloride composition, which evolved from interaction of evaporated seawater filling the late Neogene Sedom lagoon with the Cretaceous carbonate rocks exposed at the basin-bounding escarpments. Following the disconnection of the lagoon from the open sea and the development of inland lakes, the composition of the ancient Sedom brine changed due to precipitation of evaporites and addition of salts from incoming fresh water. Relative to highly evaporated seawater, these processes led to enrichment of the brines in Cl, Br, Mg, Ca, and K and depletion in Na and SO 4 . The modern Dead Sea, representing a recent product of these evolutionary processes, derived its ingredients from residual brines that remained after the desiccation of the late Pleistocene Lake Lisan, from incoming fresh water, and from saline springs that emerge along the western shores of the Dead Sea. Similar sources probably dictated the composition of the Pleistocene lakes (Amora, Lisan), though their relative contribution changed through time, reflecting the control of climate on the hydrological system (e.g., the activity of saline springs).