B rown, 1972
B rown and Coleman, 1972
520-570 M a
N AJD O R O GEN Y
Schmidt and others
1973
Najd faulting
Greenwood and others
1976
510-540 M a
Najd faulting
N AJD CYCLE
530-620 M a
Ar Rimah phase
560 M a
Shammar depression
HIJAZ CYCLE
B ISHAH O R O GEN Y
570 Ma
Murdama group and
granite togranodiorite
520-530 M a
Ash Shaba phase
J’Balah group
520 Ma
Jubaylah group and lateto post-faulting granite
Shammar group and granite
to granodiorite
B aubron and others
1976
550-570 M a
B ISHAH O R O GEN Y
Granite and quartz
monzonite
Murdama group
Peralkalic granite
Calc-alkalic granite
Shammar and
Murdama groups
538 M a
Ar Raqabah phase
Hulayfah group
600-650 M a
YAFIKH O R O GEN Y
650-800 Ma
Syntectonic gneiss
and migmatite
Quartz monzonite
650-1000 M a
HIJAZ O R O GEN Y
Diorite, tonalite, granite
Halaban group
Jiddah group
Gneiss doming
Ophiolites and
eugeosynclinal rocks
JIBAHLAN CYCLE
Compression folding
J’Balah group
Distension rifting
HADIYAN CYCLE
Epeirogeny,
erosion
Compression folding
Syntectonic plutonism
Hadiyah and Furayh groups
Distension rifting
Granite and diorite
740 M a
Tuluha phase
600-650 Ma
Late-tectonic granite
Kemp, Pellaton
and Calvez
1982
Urd group:
comprising
Abt formation
Ar Rida niyah fm.
Ophiolite complex
Halaban gruop
AYSIAN CYCLE
Epeirogeny,
erosion
Compressionfolding
Syntectonic plutonism
Al Ays group
Distension rifting
785-800 M a
R AN YAH O R O GEN Y
FAR R IAN CYCLE
Injection gneiss
Epeirogeny,
erosion
Ablah group
Second diorite series
Compression folding
Syntectonic plutonism
>1000 M a
KIBAR AN CYCLE
Pretectonic granite and
granodiorite
Greenstone
>1000 M a
TIHAM A O R O GEN Y
Bahah group
Baish group
ASIR O R O GEN Y
AQIQ O R O GEN Y
First diorite series
Jiddah group
Bahah group
Baish group
Ultramafic intrusions
<1000 M a
ASIR CYCLE
Rharabah complex
Ajal group
Farri group
Mantle disturbance,
crustal distension,
proto-oceanization
Hali group and tonalite
orthogneiss
Basement gneiss
Basement tectonism
Khamis Mushayt gneiss
Older basement
Fig. 2-10. Orogenic events and cycles proposed by previous workers on the Saudi Arabian Shield. These orogenic schemes
reflect evolving ideas on how the shield developed, constrained by geochronology and structural data then available.
At the present time, the only orogenic events recognized in the shield of regional extent are the Nabitah orogeny (680-60 Ma),
which affected a large part of the central and eastern shield, and the Najd fault system, which particauly affected the northern
shield. Other orogenic events include terrane suturing and ophiolite obduction, which occurred in stages between about 780 Ma
and 580 Ma.