## 2 Geologic Setting  
The Wadi Rod Elsayalla area is located in the Southeastern Desert of Egypt. It can be reached through asphalidic rod about 120 km eastward of Aswan city and occurs between latitude 23\({}^{\circ}\)50\({}^{\prime}\)47\({}^{\prime\prime}\) and 23\({}^{\circ}\)53\({}^{\prime}\)28\({}^{\prime\prime}\) N and longitude 34\({}^{\circ}\)20\({}^{\prime}\)52\({}^{\prime\prime}\) and 34\({}^{\circ}\)23\({}^{\prime}\)44\({}^{\prime\prime}\) E (Figure 2a,b). The exposed rock units of Wadi Rod Elsayalla are represented by metavolcanics, syenogranite, alkali feldspar granite, and quartz syenite dissected by microgranite dikes as well as quartz veins (Figure 1a-f). Several studies have been carried out on the area under investigation by many authors [21; 22]. Metavolcanic rocks form a thick sequence of stratified lava flows interbedded with their pyroclastics and intruded by granitoid (Figure 2, [22]). They are composed mainly of thick lava flows of dark green to grey with some metabasalt, metadacite, and metarhylolite thrown in for good measure. Metatuffs are very fine grained and greyish green, light to dark green, black, and buff in color. They are banded, jointed, exfoliated, weathered, and highly altered. They are ash and lithtic lapilli tuffs (Figure 1a). These rocks are basaltic, andesitic, and dacitic to rhyolitic in compositions. Metabasaltic rocks are composed essentially of plagioclase laths and pyroxene set in a fine-grained groundmass. Metabandesitic rocks, which are of the porphyitic type, are composed of plagioclase hornblende, biotite, quartz, and iron oxides. Metadacite rocks are composed mainly of plagioclase, K-f feldspar, quartz, and fine biotite flakes set in a very fine-grained groundmass. Metarhylolite rocks are composed of quartz, K-feldspars, and plagioclase phenocysts embedded in a fine groundmass. The metavolcanics have an age dated between 860 and 825 Ma [23]. Figure 1: (**a**) Lapilli metauffs associating light lithic fragments, (**b**) Synerginte intrudes metavolcanics (mtv) with sharp contact, (**c**) Quartz syenite (qsy) intrudes metavolcanics (mtv), (**d**) Quartz syenite shows intensive clay alteration (cly), (**e**) Synerginte exposed to episvenitization processes (quartz dissolution), (**f**) Synerginte highly altered to hematitization (hem). Svenogranite is medium to coarse grained and reddish to pale pink in color. It is highly wethered, jointed, strongly altered, and exfoliated. Syenogranite is composed principally  
Figure 2: (**a**) Physiographic map and (**b**) Detailed geologic map of Wadi Rod Elsayalla, Southeastern Desert, Egypt according to [22]. of K-feldspar, quartz, biotite, plagioclase, and iron oxides. They contain xenoliths up to 1m of subangular metatauffs along their outer periphery. Alkali feldspar granite is coarse grained, whitish to pale white in color, and highly weathered. Quartz serine is medium to coarse grained and dark grey to pale greenish grey or pale pink in color and has a moderate to high relief. It is highly weathered and exfoliated and composed of K-feldspars, quartz, biotite, riebeckite, arfvedsonite, and a very subordinate amount of plagioclase. Greaniotoids intrude metavolcanics with sharp contact (Figure 1b,c), and they are highly altered into clay alteration, episvenitization, and hematitization (Figure 1d-f). The granitoids rocks in the Eastern Desert of Egypt vary in their composition from syenogranite and monzogranite to alkali feldspar granite, and they are dated between 610 and 550 Ma during the Late-African Orogeny [24; 25; 26; 27]. Pegmatite pockets are unmappable rocks and occur as irregular and small bodies in syenogranite rocks. They are very coarse grained, red to buff in color, and mainly composed of K-feldspar, quartz, biotite, plagioclase, and muscovite. The younger granite intrusions and their related pegmatites are dated 610 \(\pm\) 20 and 594 \(\pm\) 12 Ma [28]. Microgranite dikes crosscut the metavolcanis and granitoid of the Wadi Rod Elsayalla area.