Rock Units

Locality

south Eastern Desert

Skiekh Shadly

identified into four mappable units

Characteristics (Composition)

Represent groups of regionally metamorphosed volcanic rocks

associated and partially alternating with meta sediments

interpreted as early phase of geosyncline filling

sequence of basic to intermediate rocks

represent early stage of island arc

range in composition from basic to acidic

Age

Classification

divided into

older Metavolcanics (omv)

thick mutinous succession of pillow meta basalt associated with meta gabbro

represent part of ophiolite assembleg

basic

Younger metavlocanics (ymv)

dominantly andesitic volcanic

overlies and interfinger with metasediment

intermediate to acidic

Other Information

evolved in island arc or volcanic arc tectonic setting

Serpentinites

form well‐defined belts associating the metavolcanics & metasediments

Their type area is taken as the Barramiya

Metasediments

defined by El Ramly and Akaad (1960) as including a succession of “geosynclinal sediments"

mainly in a low grade metamorphism to medium grade

display the alternation or interfingering of sedimentation (flysch type) and volcanism

This led Akaad and Noweir (1969) to group together the metasediments and metavolcanics in one group named Abu Ziran Group

Locality

Wadi Shait

Characteristics (Composition)

Alkali Granite

Qz Diorite

Grey Older Granit

Rich in Pg

Cataclastic Or Deformed granodiorite

Age

developed during three phases

Shaitian Event (850 - 800) Ma

Hafafiet Event (720 - 670) Ma

Meatiq Event (670 - 630) Ma

Classification

Hume

Gattarian Granit

Gabal Gattar

Grey Granit

El Ramly, Akad & Nweir

Younger red Pink Granit

Grey Older Granit

Shurman

Shaitian Granit

The Oldest

Shazly

Syn orogenic Granit

More Deformed (The Oldest)

Late Orogenic Granit

Post Orogenic Granit

Other Information

form important rock unit in Egyptian basement around 40% of basement rocks

formed in island arc tectonic setting

Locality

North Eastern Desert Gabal Dokhan

Characteristics (Composition)

Consists Of Volcanic Flows Intercalate with tuffs and ignimbrite (cryptocrystalline glassy fragments)

Intermediate to acidic volcanic rocks

Andesite, Rhyolite, Dacite, Rhyodacite

colors

red to reddish purple

Have Rock Variety of Imperial Porphyry

Qz Andesite

porpheritic

red, purple

rich in Mn

Withamite

Pg +Hb

Age

Preceding the deposition of Hammamat

Boulders of dokhan on the base of Hammamat

Intercalation with the base of hammamte

indicate that Hammamat formed in the final phase of dokhan eruption

After Deposition of Arc Graditoid

Classification

other information

thickness about 120 m and flow 50 - 200 m

formed in Active Continental Margin

Locality

Eastern Desert

Wadi Igla

Wadi Hammat

Wadi Kareem

wadi shihymia

qift - qusier road

Characteristics (Composition)

Unmetamorphosed sedimentary succession

Considered as post orogenic event

deposited after rapid uplift

deposited in intermountain basins

Some Of it are contact metamorphosed

Age

Isotopes

Cross Cutting ralationship

Hammamat is younger than dokhan colcanics

REASON: base of hammat included babbles of dokhan volcanics

Hammamt is older than younger granit

REASON: Um had granit cutting hammamat

Classification

Akad first described At Wadi Igla

Red Beds

Igla Formation

Akad & Nweir divided it into 2 formations

Igla Formation

the base of succession

unconformably overlain dokhan volcanics & other rock units

Shihyimia formation

red, grey, green

divided into three members

Rasafa siltstone member (Bottom)

Um Had Conglomerate member

Um Hassan Grey Wake Member

Other Information

Intercalation of dokhan with base of hammamat group

indicate sedimentation in the same time

Locality

per-alkaline granites

Gabal El Zeit

Gabal Gharib

Eastern desert

Characteristics (Composition)

intrusive granitic rocks ranging in composition from calc-alkali to alkali granites

the last phases commonly possess per-alkaline tendencies

red to pink color

usually with rounded or oval outlines.

Their contacts with the surrounding country rocks
are sharp.

Age

within the range 620 to 530

ages can be subdivided into two major events

1- Dokhan event: spanning the time interval 620 to 570 and

2- Katherina event: spanning the time interval 570 to 530.

Classification

El Gaby (1975)

Late orogenic calc-alkali granites

elongated bodies parallel to the regional structure of the area

Post-orogenic alkali granites

red to pink color

Circular to oval outline (sharp intrusive contact)

alkaline to peralkaline in composition

rich in perthite & k-feldspar

Hussein (1982)

G I

older grey shaitian granit

formed as subduction related granit

G II

calc alkaline red to pink granit

formed in active margin (suture)

formed by melting of lower crust

G III

alkaline to per alkaline granit

formed in no orogeny OR within plate tectonic setting

depend on the origin

Gneisses & schists of sedimentary origin (psammitic)

consist mainly of quartz (50 ‐ 80%), potash feldspar, plagioclase & mica

Gneisses of igneous origin(Orthogneiss)

The oldest igneous rocks in the area are foliated metagabbros (hornblende gneisses) similar in their geochemical characters to mid ‐oceanic ridge basalts (MORB) and consequently they are believed to pertain to an ophiolitic assemblage

Migif ‐ Hafafit area in south Eastern Desert

Characteristics (Composition)

occur within a spectacular Precambrian structure

associated rocks are of sedimentary & igneous derivation

The rocks revealed the following age succession

Gneissic tonalite. (Youngest)

Intrusive calc‐ alkaline metagabbros

Psammitic gneisses (probably derived from continental sources)

Biotite schists (interlayered with bands rich in hornblende)

Foliated metagabbros (the hornblende gneisses?) pertaining to an old oceanic crust

Ultramafic rocks of ophiolitic affinity. (Oldest)

Gabal Meatiq in the central Eastern Desert

Wadi Feiran in the south western part of Sinai

cover about 7% of the Egyptian Basement