**1. Introduction**

The use of electron microscopy enables us to observe the size of minerals and understand their formation and the relations between various minerals in sediments. By using scanning electron microscopy (SEM), the size of minerals can be measured, morphology and relations between phases like coating or erosion of crystals can be observed. Using energy dispersive systems (EDS), the chemical composition of minerals can be obtained. The use of transmission electron microscopy (TEM) or high resolution transmission electron microscopy (HRTEM) enables us to measure the size of nanocrystals, obtain their chemical composition and identify the minerals formed.

With HRTEM, short range ordered phases can be identified and recrystallization of the minerals preserving initial morphology can be observed [1].

In this chapter, samples from various sites from Israel and the central Red Sea Deeps are presented and described. Rounded quartz grains arrive from the Nile River in Egypt to the Nile Delta, then are moved from the Delta with longshore current along the southeastern Mediterranean Sea to the Israeli coast. Moving of the grains to the coastal plain results from transgression and regressions of the sea causing the formation of sandstone ridges and soils [2]. The sand was also blown inland, forming sand dunes and eolianite calcareous sandstones ('kurkar').

Carbonate layers and marl or clay layers were formed during the Cretaceous period transgression of the Thetis Ocean. At the end of the Cretaceous, the layers were folded as part of the Syrian arc and the Judean Mountains were formed [3]. The maximum elevation of 1000 m separates between the western side of the mountains and the Judean desert on the eastern side.

The hypersaline terminate lake of the Dead Sea is located along the Dead Sea Transform fault at the eastern side of the Judean Mountains. The desert in the area causes evaporation of the Dead Sea water leading to elevated salinity of 340 g/l and precipitation of halite crystals [4].

Dust storms are common in Israel, mainly during autumn and spring. During the winter, dust storms appear at the early stage of rainstorms. The dust arrives either from North Africa from the Sahara desert or Saudi Arabia, depending on the weather cyclones [5]. The dust contains coarse silty quartz grains sourced from Sinai and the Negev in southern Israel [6].

The Atlantis II and Thetis Deeps are located in the central part of the Red Sea along the axial rift separating the Arabian and African plates. Hydrothermal brine discharges into the Deeps and the salinity results from dissolution of Miocene evaporates [7]. Elevated temperature results from interaction with hot magmatic and peridotite rocks, located underneath. Dissolved iron that is discharged from ultrabasic magmatic rocks, reacts with oxygen to form various phases of iron oxides. A narrow channel connects the southern Atlantis II Deep with small chain and discovery basins [8]. Drillings were performed during 'Mesada 3' expedition by Peussag company from Germany in the late 1970s and at the beginning of the 1980s as a part of the 'Saudi Sudanese Red Sea joint commission for exploring of red Sea Resources'. Samples were kept under 4°C in institut für meeresforschung (IFM) Geomar in Kiel, Germany [9].
