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In the current manuscript, Miocene carbonates of the Eratosthenes Seamount (ODP Leg 160, Site 966), have been re-analyzed. The succession of the Eratosthenes Seamount is characterized by a diverse large benthic foraminifera assemblage in its lower part and by corals in its uppermost part, whereas corallines characterise the central interval. This trend is common in Miocene Mediterranean carbonates and its occurrence on an isolated seamount confirms its connection with the general evolution of the basin. The decline of miogypsinids and lepidocyclinids after the early Miocene is notable because the Eratosthenes Seamount was geographically close to the Indo-Pacific Ocean where both groups also thrived during the middle Miocene. This decline was probably caused by the early Miocene closure of the deep-water connection between the Indo-Pacific and the Mediterranean.

In the associated figure, a paleoenvironmental reconstruction of the Miocene succession of the Eratosthenes Seamount is shown.

Follow this link for full access to the paper. Congrats Ari!

Understanding the petrophysical parameters that characterize the subsurface is an important tool to learn about all the different processes that affect its structure through time. Ido's study focused on the relationship between the physical and electrical properties of the subsurface and the decay of the magnetic field, which appears to depend on the lithology and depth. For this purpose, the southern Negev desert, which is characterized by alternation of sands and lime, has been chosen as a test site. The results show a clear connection between the structure of the subsurface and the physical parameters and the magnetic field decay within a shaft. For example, one of the measured parameters is conductivity, which greatly varies depending in the lithological variability with depth (see associated figure).

Congrats Ido for his achievements and great success in his continuation in a PhD in cooperation with the University of Waterloo, Canada!

In the current paper published in Earth Science Reviews, we provide a multidisciplinary study of sedimentary, geochemical, and geophysical data from industrial offshore wells in the Levant Basin, which recovered a sedimentary record of deep-basin Mediterranean evaporites deposited during the Messinian Salinity Crisis (MSC). In combination with previous observations of the MSC throughout the Mediterranean Basin, our results promote the need for a new chronological model. Remarkably, the one-kilometer-thick lower part of the evaporitic unit is composed of essentially pure halite, except for a thin transitional anhydrite layer at its base. In the current study we show that distinct, meters-thick non-evaporitic intervals interbedded with the halite, previously thought to be clastic layers, are diatomites. The occurrence of marine planktonic diatoms in these intervals indicates the input of Atlantic waters into the Mediterranean Basin during the deposition of the massive halite unit. Seismic stratigraphy and well-log cyclostratigraphy further support deep basin halite deposition, which started about 300 kyr earlier than widely assumed (~5.97 Ma). We propose that halite deposition in the deep Mediterranean took place during stage 1 of the MSC, rather than being limited to the short 50 kyr MSC acme when sea level was presumably at its lowest. Thus, brine formation, salt precipitation, and faunal extinction occurred at least in part in a deep, non-desiccated basin, with a restricted yet open Mediterranean-Atlantic connection that allowed inflow of oceanic water. We observe an increase in heavy minerals and reworked fauna within the clastic-evaporitic, Interbedded Evaporites of the basinal MSC section, and argue that these settings correspond in the deep basins with a significant sea-level drawdown during stage 2 of the MSC, as observed in the marginal sections. This correlation is corroborated by astrochronology and chemostratigraphic markers, such as the distribution of n-alkanes and biomarker-based thermal maturity indices. The Levant deposits indicate that high sea level and partial connectivity with global oceans promoted the deposition of deep-basin deep-water halite, while sea-level drawdown promoted deposition of reworked and transported material from the margins into deep Mediterranean basins.

This study modifies the current understanding of the mechanisms governing salt deposition throughout the MSC with implications for other evaporitic events in the geologic record.

Congrats Ari!

Parth Dharmendrabhai Shah from India joins PetroLab as a PhD student. Parth completed his BSc and MSc at the Indian Institute of Science Education and Research Mohali, India. During his MSc, Parth worked on biomarker distribution and nitrogen isotope composition of lacustrine sediments from Kashmir and Southern India. His PhD deals with reconstruction of the African Humid Period termination pattern in the southern margins of the Saharan and Africa utilizing a series of lake systems. Parth won a competitive scholarship from the Israeli Government that granted his stay here. Congrats Parth for the scholarship and we wish you a prosperous academic record in Haifa!