Petrography and Geochemistry of Urf suite from Aqaba ... · Calc-alkaline granitoids (ca. 630–610...

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 8 (2018) pp. 5772-5787

© Research India Publications. http://www.ripublication.com

5772

Petrography and Geochemistry of Urf suite from Aqaba complex,

Southern Jordan

Ali S. Ben Sera¹ ⃰ , Ghaleb H. Jarrar ²

¹ ² Institute of Geology, University of Jordan, Queen Rania Al Abdallah Str. 11942 Amman, Jordan.

* Corresponding author

Abstract

The Aqaba complex located at the south-eastern of Jordan,

exposes coexisting mafic–felsic association typical of syn- to

pre-plate collision magmatism. The bulk of the pluton is

made of quartz monzonite, granite and granodiorite. New

U–Pb zircon dating revealed a synchronous emplacement of

the granite (605 ± 4.6 and 617±3.7 Ma), granodiorite (613

±4.4, 612 ±3.6 and 611.8±4.9 Ma) and quartz monzonite

(608± 5.4 Ma). The whole-rock geochemistry indicate that

the source for the quartz monzonite, granite and granodiorites

could have been a continental arc-derived from mantle

sources and mature metagreywackes. Melting of this crustal

material was subduction related , which could have been an

enriched mantle-derived melt contaminated . The Aqaba

complex is a part of a the Arabian-Nubian Shield (ANS) are

juvenile in character, Neoproterozoic, including in addition

five large plutonic suites ; Rahma , Darba , Rumman,Urf

and Yutum suite. The genesis of these suites were likely

induced by mantle-derived magma in the shallow crust while

their spatially and temporally discrete emplacement at shallow

levels was probably related to the (extensional) of

lithospheric boundaries, which represent a feasible fertile

source for such granitoids.

Keywords: Aqaba complex, U–Pb geochronology, Arabian

Nubian Shield, Continental arc magmatism, I-type granite.

INTRODUCTION

The tectonomagmatic evolution of the northern part of ANS is

divided into two stages: an early stage (880–740 Ma)

representing the island arc accretion stage [32,45,46] and a

later post-collisional stage (680–580 Ma). The late

Neoproterozoic post-collisional stage peaks at 630–620 Ma

and is characterized by the intrusion of calc-alkaline and

alkaline granitoids [10,31,45,11]. The plutons produced

during these magmatic events, referred to as post-collisional

and subsequently post-orogenic, differ from the preceding

syn-collisional suites in that they have more primitive

compositions [13]. During collision, the continental crust is

strongly reworked by imbrication of tectonic units derived

from different crustal levels while the lithospheric mantle may

have been modified by preceding subduction. As a

consequence, extremely diverse rock-types, ranging from

silicic peraluminous to high-K calc-alkaline or alkaline suites

may arise due to the variability of the potential sources

[57,38,7]. Bentor (1985) has been divided the northern ANS

into four main phases ; phase I ( 900 – 870 Ma) was

characterized by a several kilometer thick sequence of

tholeiitic basalts. Phase II ( 870 -650 Ma ) was characterized

by mainly calc-alkaline, island arc magmatism, followed by

extensive metamorphism. Phase III ( 630 – 600 Ma) was

mainly characterized by intrusion of calc-alkaine granitic

batholiths in the north of ANS. Phase IV ( 600-530 ), was

characterized by alkaline igneous activity of bimodal

character [27]. The Aqaba complex is made of five composite

granitoids suites and several metamorphic suites (Abu Barqua

metasedimentary suite and Janub metamorphic suite (Fig.1).

In this paper we present new geochemical data on the Urf

suite with an included a set of details and provides the

opportunity to reconstruct the Aqaba complex with the use of

geochemical parameters. Many studies have investigated

(mainly [27,40] chronostratigraphical relationships between

granitoid suites in South of Jordan, based on Rb-Sr ages.

However, these are generally believed to be about 10–20 My

younger than the corresponding radiometric ages based on

more reliable U/Pb zircon ages. U/Pb zircon ages thus provide

a more robust geochronology for the Araba Complex (ca. 600

to 550 Ma) and the underlying Aqaba complex (ca. 604 to 900

Ma). The Aqaba complex is composed of I-type suites that

display numerous younger – cutting dykes intrusion. The

Araba complex is bounded by two major erosional

unconformities, the newly defined Ediacaran Araba

unconformity (ca. 605 Ma) at its top, Araba complex

underlain by the Aqaba complex, and the post-extensional,

regional lower Cambrian Ram unconformity (ca. 530 Ma) that

marked by the widespread deposition of thick alluvial and

marginal-marine siliciclastics (Ram Group).

GEOLOGICAL SETTING

Neoproterozoic evolution of the Arabian Nubian Shield

The Arabian Nubian Shield in northern Jordan is as a result of

the East-African Orogeny (900–550 Ma; [54], records the

most comprehensive events of continental crust formation

[56]. It has formed as a consequence of accretion of several

arc-terranes. Formation of the ANS took place through

several stages ; A) intra-oceanic subduction orogenic

evolution (∼300 Ma ) B) arc and back-arc magmatism (870–

700 Ma), and finally, through terrane amalgamation (∼800 to

650 Ma) between the main fragments of East and West

Gondwana with companion of extension and delamination

(630–550 Ma) of formation of newly continental crust

[55,36,54,36,22,2,34]. [7,58,54] provided an excellent

modeling of construction of ANS , they related to the

amalgamation of Gondwana and the accretion of intra-oceanic

arcs , which leading to the closure of the Mozambique Ocean.

mailto:[email protected]



5773

Fig

ure

1:

Sim

pli

fied

geo

log

ical

map

of

the

Aq

aba

com

ple

x s

ho

ws

the

dis

trib

uti

on

of

cry

stal

lin

e b

asem

ent

rock

s in

sou

ther

n o

f Jo

rdan

. (M

od

ifie

d a

fter

McC

ou

rt

19

90

et

al.,

).



5774

This model is widely accepted, initiates the formation of the

ANS with seafloor spreading and the creation of arcs and

back-arcs following and during the breakup of Rodinia.

Formation continued with the amalgamation of arc terranes

and a few older continental fragments into new juvenile crust

between about 870 Ma and 690 Ma. Some references

[9,36,58,58,56,1,34,55] mentioned that the uplift and crustal

thickening were as result of shortening and Continental

collision, may be beginning ∼750 Ma and continued with

until the end of the Precambrian. According to [2] in general ,

the thickness of the granitoid rocks of the northern ANS is

33–37 km. [29,45,46,52] divided the northern part of ANS

into two stages: an early part (880–740 Ma) representing the

island arc accretion stage and a later post-collisional stage

(680–580 Ma). The second stage is post-collisional stage, and

characterized by calc-alkaline and alkaline granitoids at about

630 Ma [8,28,5,19,45,56].

Geology of the Aqaba Complex

The Neoproterozoic basement outcrops in southern Jordan,

include the northernmost part of ANS and represents the

northernmost edge of the ANS. Geochemical, petrological and

geochronological constrains indicate the presence of two

distinct types of granitoid rocks within the Arabia and Aqaba

complexes : an older (617 – 604 Ma), and Araba complex

(younger 600-550 Ma; [45] also referred to syenogranite, calc-

alkaline, synplutonic diorite to granodiorite assemblage. Most

famous studies, which have been concerned with

geochronology and geotectonic evolution of the granitoid

rocks in Araba and Aqaba complexes [29,30,31,32,40,42].

However, we still miss the perfect perception on several

important points on the one hand , in particular their source of

crustal granite pluton and the role of fractional crystallization

vs. crustal anatexis. Also, on the syn- vs. late-orogenic

geotectonic setting for the alkaline calc-alkaline granitoids on

the other. Large volume of granitoid crust is, which

distributed within the shield is not homogenous. In the

northern ANS, inclusive of northwestern Arabia and the

Eastern Desert of Egypt (ED) and Sudan, Sinai and Jordan,

granitoids comprise about 60% of this expanse of

Neoproterozoic rocks [17,15], while in South Ethiopia and

Kenya, the constituts mainly 40% of the total expose [17].

Calc-alkaline granitoids (ca. 630–610 Ma) in Jordan mostly

considered as the Aqaba complex suites, syn-to post-orogenic

granites, [50,40,21,23,38], subduction-related [29,36].

(Stoeser et al., 1985) contribute a basic model for granitoids in

northern ANS as result from mantle derived and the partial

melting of similar, volcanic arc material during subduction at

a continental margin, which was producted movement of the

approach of the 'Arabian neocraton' to cratonic Africa, and its

follow collision subsequenting closure of the intercedeing

oceanic crust, at the culmination of the Pan-African orogenic

events. ANS rocks constitute a major of the basement outcrop

in the southern Jordan.

Study area and sample description

The outcrop was excellent exposed, but deeply weathered.

Ten samples including ; plutonic quartz monzonite, granite ,

monzonite-diorite and monzonite–gabbro. All samples were

cleaned, sawn and crushed in preparation for petrographical

and geochemical analysis. The study area is located between

Latitudes 35º04' and 35º15'E and Longitudes 29º30' and

29º50'N, covering an area of about 50 km² (Fig.2). The field

works, which dealt with petrological description and

geochemistry of the granitoids .

PETROLOGY

Below, we give a summary of new data concerning the field

relationships and petrography of the Urf suite.

Urf Suite

Filk quartz monzonite

Urf suite is located in northeast, the name of the suite is

proposed, after the type area around Jabal El Urf, outcropping

over some 220 km², the Urf suite comprises the Abyad

granodiorite, Filk quartz-monzonite, Rubeiq monzo-diorite,

Muheirid granodiorite, Marsad monzogranite and Barraq

granodiorite. The suite extends from the Wadi Araba in the

west to Quwayra in the east and formed low undulating

ridges and are cut by numerous dykes (Fig.2). The dyke

shows the full range of composition from dolerite to

porphyritic microgranite, but black to black –green basic

dykes are the most conspicuous. ( Fig.2 ). The Urf suite

comprises medium grained quartz monzonite monzo-granite,

containing subhedral, tabular, white or pink feldspar

phenocrysts enclosed within a uniformly textured groundmass

of feldspar , quartz and biotite (Fig.3). The Filk and Rubeiq

units are the most widely developed phase and are to be

interpreted carefully in this study. The suite crops out within a

NE-SW of orientated belt of undulating and isolated and

subrounded rubbly hills. The Filk granite-quartz monzonite

has a medium grained, white and grey groundmass containing

essential dark platy biotite with minor chloritisation, perthitic

alkali-feldspar (Fig.3), anhedral white oligoclase and clusters

of milky quartz ( Fig.3). Rapakivik texture is characterized

and good defined in Filk unit. The phenocrysts comprise

subhedral to anhedral , rectangular to rounded, pink perthitic

orthoclase and zoned plagioclase (Fig. 3C). As accessories are

apatite, iron oxides and titanite.

Rubeiq monzo-diorite

The Filk and Rubeiq units are the most widely developed

phase and are to be interpreted carefully in this study. The

Rubeiq unit is typically exposed on Tulul ar Rubeiq ,

northwest of Al Quwayra (Fig.1), is highly characterized with

pink rectangular phenocrysts of orthoclase in medium to fined

groundmass of perthitic orthoclase and zoned plagioclase

(Fig.3). Rubeiq unit is a medium to coarse grained, quartz has

a characteristic greasy lustre, but typically fractured, also,

mafic minerals subhedral and weakly aligned typically biotite

(Fig 4). Sphene and apatite accessories.



5775

Figure 2. Urf suite. A) Rubeiq unit .B) Filk granitoid unit C ) Rapakivik texture

D) Urf suite outcrops at desert highway to Aqaba city.

The collected samples from Rubeiq unit related to be tonalitic

to monzo-gabbro and display a transitional alkaline character

based on major element. Also what distinguishes this is the

lack of xenoliths. The two units also often have a weak and

highly variable biotite foliation ( Fig.3 ), though to be due

to post-consolidation faulting. The contact between the

Rubeiq and Filk units is poorly exposed and appears as

pegmatites and expands and grows into the Filk pluton. The

major distinguishes in the field that in Filk unit, are the

abundance of dykes, the area was heavily dyked (Fig.3),

rapakivi texture (Fig.3) is dominanted in this suite. K.Ibrahim

(1990) suggests that many of the mapped units of the Urf suite

are essentially coeval or closely related pulses of a common

magma source. On based Rb-Sr is the Urf suite, corresponding

to an age ca. 620 Ma ; [40] ; [27]. I personally consider that

age needs to be reconsidered, where it is considered to be

younger than the other suites (e.g. Rahma , Darba tonalitic

…etc), and according to field observations, the age is not

logical. What distinguishes this suite is the metamorphic rocks

of (Duheila and Buseinat suite) occur as horst structure on

isolated , low and small hills with smooth topography ( Fig.4),

which rise above the alluvial fans at the western foot of the

granitoidic rocks (Rahma suite ). The two suites outcrop in

northwest of Urf suite and within the Rahma foliated suite (

Fig.4) , lying along the faulted eastern edge of the Wadi

Araba. The outcrops of the metamorphic rocks occur as both

suites are more extensively developed to the north, in Wadi

Duheila and Tell Buseinat. The suites are characteristically

dark grey and typically displays banding and schistosity (

Fig.4). Two major lithotypes predominant mainly Buseinat

suite and biotite orthognesis and schist ( Fig4). The

orthognesis and schist are almost uniform in texture ,

commonly with a weak biotite foliated or indistinctive

layering. Measurements of foliation in the type area show the

strike to range between NNW-SSW and NNE-SSW ( Fig.4 ).

Petrographically, the gneisses consist of subhedral to



5776

anhedral, medium grained andesine plagioclase with a well-

developed albite twinning and intensive sericitisation, fine to

medium grained anhredral quartz with wavy extinction, and

consertal intergrowths and tabular elongate brown crystal of

biotite orientated in bands and slightly weathered to iron

minerals and chlorite (Fig.4 ).

Figure 3. A plutonic classification scheme modified from De la Roche et al. (1980) of Filk and Rubeiqunit samples from the

Aqaba complex with micrography. This diagram indicates that the samples collected are classified as granite- quartz monzonite

and alkali gabbro to monzo-gabbro.



5777

The schists are similar in composition , but with more chlorite

and a greater degree of mineral segregation, forming the

schistose structure. As secondary minerals including apatite

and sphene. Contact relationships with the Rahma suite seen

in the field clearly confirm the intrusive nature and the

common observation that gneissic foliation is normal to

contact with the granitoids (Fig.4 ). Absolute ages for the

suite are not available before. I took several samples from the

studied area to study and estimate its age ; it is intrujected by

the Rahma suite (617Ma ; Ali Ben in press). The orthognesis

and schist lithotypes of Buseinat suite represent,

metamorphosed granitoids and dyke rocks from a single

episode of plutonism into a sedimentary succession. Duheila

suite , the name was proposed after the location ; in Wadi

Duheila , about 36 km north of Aqaba city. The suite, occurs

as roof pendants, megaxenoliths , xenoliths and stock-shape

outcrops in the Rahma foliated suite, association in part with

Buseinat (fig.4). The suite is phanerocrystalline and very

coarse grained ( pegmatite ) with dark green, prismatic (

finger-like ), giant crystals of hornblende and with milky,

while plagioclase filling interspaces ( Fig.4), which are

pinkish red in part probably due to metasomatism. A dark

green porphyritic variety contains idtiomorphic amphiboles

(Hornblende/actinolite) and shows both two and one sets of

cleavage. Contact of suite with Rahma and Urf suite are sharp

and intrusive. (Fig.4 ). It appears , based on field evidence

only that the hornblendic suite is older than both the

granitoids of Aqaba complex. The age relationship with

Buseinat suite is unclear, nor is absolute age data available.

Thus an age range of between 608-820 Ma is inferred for

metamorphism [29]. The suite may be volcanic and/or

metamorphosed basic, which might related to the source of

metadyke. The lack of garnet in the metabasic rocks of this

suite may reflect a lower metamorphic grade .

ANALYTICAL TECHNIQUES

Major and trace elements for the samples, were preparation of

rock powders for analyses was performed at the geology

department, University of Jordan. The major oxides and trace

elements were analyzed by meta-borate fusion ICP-OES

technique, while the trace elements including REE were

determined by Inductively Coupled Plasma-Mass

Spectrometry (ICP-MS) techniques at the petrotectonics

analytical facility.

ANALYTICAL RESULTS

A wide range of rocks are represented in the pluton, ranging

from 45 to 76 wt. % SiO2. (Table 1 ). Using the P–Q

multicationic plot [14], samples can be classified between

quartz monzonite endmembers, with transitional compositions

corresponding to monzodiorite, and monzo-gabbro (Fig.5-A).

The B–A plot (Fig. 5-B) [14] can be used to express the

contents of mafic components Fe, Mg and Ti (B), their

relation to the aluminium balance (A) and thus the

characteristic mineral assemblage. Samples define a trend

from the hornblende > biotite metaluminous field for quartz

monzonite and monzodiorite. Rubeiq unit is more syenite and

alkali gabbro (Fig. 5-C) [44]. The suite is I-type granite

(Fig.6-A) [59], composed of sub-alkaline rocks, as

demonstrated by the TAS diagram [44] (Fig. 6-B) and, defining as a calc-alkaline series in the AFM diagram (Fig.6-

C) [28] and following a high-K calc-alkaline trend in SiO2 vs.

K2O plot (Fig. 6-D) [48]. In terms of alumina saturation

index [57], the samples are dominantly metaluminous (Fig.6-

E), the studied samples commonly lack normative corundum,

and instead contain normative diopside, with relative low

A/CNK ratios. All samples plotting extension an active

continental margins (Fig.10f ) [51].

The suite shows a quite limited and distinct compositional

variation. Urf suite is dominanted by more evolved

monzonite, with silica contents ranging between 45 and 70

wt%, Mg-numbers (Mg# = varying from 10 to 70 ( Table 1 )

with low MgO (0.3–4.3; average = 1.68 wt%). CaO (1.35–

12.43; average =5.5 wt%) content, and conversely, by low

total alkalis (0.20–1.32; average = 0.62 wt% ) (Fig.7). The

low total alkalis averages not exceed those of all genetic

types low abundances in K2O and Na2O. The Urf suite

displays an extended narrow of evolved compositions,

represent a compositional gap between 45 and 55 wt% SiO2

values with high negative linear trends exception of total

alkalies (Na2O + K2O), the samples display well-defined

trends for the rest of the major elements with differentiation

(silica rise) (Fig.7). Such overall scatter on Harker diagrams

may be interpreted as due to inter-pluton variations,

representing mixing between various magma pulses, where

each individual pulses defining a relatively coherent trend.

alternately, such scatter can be interpreted crustal

contamination during magma process such as storage and

ascent. The studied samples exhibit contrasting trends where

total alkalies show scattered distribution to positive linear

correlation and the other major elements display variably

negative linear correlations against silica. The substantial

scatter in Na2O + K2O may reflect mobilization of these

elements by secondary processes. Also, the co-linear trends in

many Harker variation diagrams appointed by many factors

(such as xenoliths, host rocks and dykes) can be accounted for

by such a MFC process during crystallization.



5778

Figure 4. Buseinant suite , petrographic photos of Duheila hornblendite and gneiss A&B) Duheila hornblendite C) contact

between Duheila hornblendite and gneiss D&E) Photomicrograph of a thin section of Duheila hornblendite in cross-polarized

light.G ) Photomicrograph of gnesis in cross-polarized light.F) representation the schistose structure.



5779

Figure 5 A) P–Q multicationic plot of Debon and Le Fort (1983). (B) – B–A plot after Debon and Le Fort (1983).

(C) – TAS diagram after (TAS) diagram for classification using silica vs. alkalis for plutonic rocks of samples

of Urf suite (Middlemost, 1994).

Table 1. Represents major elements (%), calculated CIPW and some chemical ratios of Urf suite from Aqaba complex , Southern

Jordan. Symbols; Filk unit=FM, Rubeiq unit=RQ

Sample FM1 FM2 FM3 FM4 FM5 RQ1 RQ2 RQ3 RQ4

SiO2 71.9 71.7 70.4 69.6 71.2 52.2 53.3 45.7 47.6

Al2O3 16.3 17.1 17.5 17.7 16.7 24.0 24.4 23.2 24.2

CaO 1.7 1.6 1.4 1.9 1.5 8.8 8.7 12.4 11.6

MgO 0.5 0.4 0.3 0.7 0.5 2.7 2.6 4.3 3.3

MnO 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.1

P2O5 0.1 0.1 0.1 0.2 0.1 0.9 0.8 1.2 1.3

Fe2O3 1.4 1.1 0.9 1.8 1.4 5.2 4.8 8.0 7.7

Na2O 4.0 5.1 6.4 4.4 4.1 1.4 1.5 0.7 0.8

K2O 3.04 2.86 2.91 3.45 3.04 2.44 1.93 2.93 2.92

TiO2 0.3 0.3 0.3 0.4 0.3 0.8 0.8 1.6 1.3

H2O- 0.93 0.93 0.79 0.70 0.87 1.42 0.93 0.77 0.58

H2O+ 0.06 0.04 0.02 0.05 0.02 0.05 0.03 0.01 0.04

K2O/Na2O 0.74 0.74 0.74 0.74 0.74 0.74 0.74 0.74 0.74



5780


(K2O+Na2O)/CaO 5.42 6.56 8.31 5.15 6.38 0.70 0.70 0.73 0.39

CaO+Al2O3 18.04 18.65 18.8 19.6 18.14 32.76 33.08 35.66 35.82

FeO*/MgO 2.74 2.41 3.07 2.19 2.66 1.71 1.66 1.67 2.12

FeO*/(MgO+MnO) 2.57 2.29 2.85 2.08 2.50 1.67 1.63 1.68 2.07

Mg# 12.87 9.63 8.28 16.20 12.51 46.51 43.20 72.35 68.84

CIPW

Q 29.18 18.31 14.77 15.99 20.61

C 2.51 0.31 0.26 0.78 0.85

Or 23.69 29.84 37.7 25.82 24.28 8.39 8.8 3.84 4.49

Ab 33.93 44.25 40.87 46.96 45.52 39.66 40.95 23.72 28.74

An 7.78 7.13 6.24 8.07 6.67 39.93 40.31 48.35 46.97

Di 0.24 0.13 0.53 1.57

Hy 1.71 0.99 0.67 1.84 1.71 0.21 6.05 3.81

Ol 4.67 4.53 5.59 4.43

Il 0.06 0.043 0.04 0.086 0.06 0.12 0.1 0.21 0.17

Hm 1.43 1.07 0.9 1.8 1.3 5.16 4.8 8.04 7.65

Tn 0.27 0.24 0.23 0.35 0.22 1.24 1.02 2.48 2.11

Pf 0.3 0.23 0.16 0.54 0.26 0.12

Ru 29.18 18.31 14.77 15.99 20.61 0.3 0.23 0.166 0.54

Ap 2.51 0.31 0.26 0.78 0.85 8.39 8.8 3.84 4.49

Continued table 1

Table 2. Trace elements (ppm) of Urf suite, Aqaba complex


Ba 658.3 647.6 640.0 775.0 601.6 599.6 590.6 426.8 658.3

Cr 84.33 95.30 71.57 67.07 100.8 121.8 95.60 81.87 84.33

Cs 2.75 3.00 2.23 2.21 2.39 4.07 3.76 4.10 2.75

Ga 18.45 19.07 17.84 16.01 18.84 18.79 17.84 16.42 18.45

Hf 3.65 5.03 3.49 3.29 8.29 6.90 4.37 4.92 3.65

Nb 6.62 6.52 5.11 5.10 7.93 7.96 5.98 7.33 6.62

Ni 41.87 42.20 42.53 78.53 81.27 64.50 57.87 45.50 41.87

Pb 21.35 21.49 25.16 24.28 25.81 23.18 23.69 22.13 21.35

Rb 73.03 68.37 66.67 70.77 67.63 75.37 71.57 71.03 73.03

Ta 0.59 0.58 0.47 0.46 0.85 0.94 0.57 0.74 0.59

Th 11.67 15.84 8.24 8.60 10.56 10.54 8.17 13.01 11.67

U 1.37 2.09 1.53 1.56 2.85 2.88 2.10 2.23 1.37

Zr 140.5 184.1 128.4 118.5 330.3 262.8 158.9 174.7 140.5



5781

Figure.6. Plots of Urf suite : (A) I-Type granite discrimination diagram (after Walen et al.,1987).(B) FeO/MgO vs. SiO2 diagram

with boundary between tholeiitic and Calc-alkaline rocks (after Irvine et al.1971) .(C) Subdivided discrimination diagram (after

Sylverster 1989) .(D) Plot of K2O vs. SiO2 diagram (after Peccerillo and Taylor, 1976). (E) A/CNK vs. A/NK plot (Maniar and

Piccoli 1989) .F. Th/Hf vs. Ta/Hf (after Schandl and Gorton 2002).



5782

Figure 7. Harker variation diagrams for the Urf suite: (a) Major oxides (wt%). Harker diagrams display negative linear

correlations of SiO2 with TiO2, FeOt, MgO, CaO and Al2O3, while P2O5 is slightly inflexed (Fig. 6). after which Al2O3

decreases due to the onset of plagioclase fractionation. FeO, MgO (not shown) and CaO decrease with increasing silica, which

reflects the separation of olivine, magnetite, pyroxenes, and plagioclase. Na2O and K2O show positive correlations with marked

inflexion at ~65 % SiO2. Sodium prevails over potassium in quartz monzodiorite (K2O/Na2O = 0.58–0.70 by weight), whereas

this ratio ranges from 1.2 to 1.5 in granites.



5783

DISCUSSION

Origin of the Urf suite

Numerous tectonic settings have been suggested for the

genesis of Aqaba granitoid rocks, which are mainly:

continental arc, post-collisional arc and syn-collision settings

[49]. In addition, the generation of continental arc igneous

rocks could be associated with subduction activity [49]. The

majority of our samples represent volcanic-arc granites field.

Nd isotopic studies have demonstrated that the ANS, in many

terranes in northern ANS are overwhelmingly comprised of

juvenile crust, i.e. of mantle derivation during the

Neoproterozoic in an intra-oceanic environment [23,22,55].

It’s early development and represented by juvenile calc-

alkaline magmatism [23]. As shown in (Fig.8 ), the Urf suite

suggests that the samples derived by partial melting of felsic

metapelites.

Fig.8 Source rock discrimination diagrams for the meta-pelite samples (fields of melt compositions in (A and B) after Patino

Douce, 1999), in (C) are after Altherr et al. (2000) .

Most of the studied samples have Y/Nb ratios exceeding 1.2,

characterizing crustal-derived rocks. while some samples

(Urf suite) have ratios lower than 1.2 (i.e. mantle source), it is

evident that the Urf suites share geochemical features of

mantle and crustal source materials. In both of the major

elements-based the multicationic R1–R2 (Batchelor and

Bowden, 1985) and SiO2-FeO⁄/(FeO⁄ + MgO) (Fig.33; [39])

tectonic discrimination diagrams, the suite samples are

classified as normal continental arc & continental collision

granite and as late orogen, post-collision uplift and pre-late

collision granites (Fig.33; [33], most samples from Filk unit

fall in the late orogeny, but Rubeiq unit are pre-plate collision

.



5784

Figure 9 (A) Ta+Th vs. Rb plot (after pearce et al. 1984). (B)- R1-R2 plot (after Batchelor and Browden 1985).

(C). FeOt/(Fe2O3+MgO) vs. SiO2 ; after Maniar and Piccoli, 1989. (D)- Rb-Hf-Ta discrimination diagram

(after Harris et al.1986). (E)- Nb vs. Rb/Zr bivariate (after Jin, 1986).

Petrogenetic Mechanism

However, several diagnostic geochemical criteria are

presented and supplementary tectonic discrimination schemes

are additionally employed in the following sections to reveal

the paleo-tectonic environment in which these granitoids have

been emplaced. Urf suite reflect different chemical affinities

may represent different source rocks rather than different

tectonic settings, where the I-type and calc-alkaline intrusions,

most likely introduced by fractionation of mafic melts

produced by partial melting of mantle with little crustal

contamination of granulitic lower crust in subduction zones

[18] With regard to their magma origins, one proposal is that

they derive from anhydrous high grade metamorphic rock, for

example, granulite that had previously yielded a granitic

partial melt [9], although it is very hard to understand how

such depleted material could generate such enriched melts.

Another proposal is that they derive from mafic to

intermediate calc-alkaline crust made up of diorite, tonalite,

and granodiorite [4]. This model, is closest to right as applied

in the Aqaba complex ; encompasses the melting of earlier

arc rocks followed by anhydrous fractionation giving rise to

magmas that retain a calc-alkaline signature [29], [27]. In

(Fig.34) representing the tectonic summary by the tectonic

modeling of Aqaba granitoids. These geochemical

characteristics are suggestive of the generation of Aqaba

complex, by amounts of crustal assimilation/fractionation.



5785

Figure Generalized lithospheric structure for Aqaba complex , the Northern part of the Arabian Plate. The depth of continental

crust has been determined by (El-Isa 1984) using a seismic refraction, also the thickness is about 35 km. The basement rocks is

exposed at a depth of 2-2.5 Km (El-Isa 1984) . Transition zones boundary between the upper, the uppermost and mantle the lower

crust at about 20 km (El-Isa 1984).

CONCLUSION

- The (ANS) derived from mantle sources are

essentially juvenile and formed new continental crust

during the Neoproterozoic.

- 10 samples were studied carefully and allowed

subdivision into metaluminous and calc-alkaline

series. These granitoid samples are plotted VAG and

are classified as I-type granite.

- Geochemical parameters, the samples are derived

clearly from the mantle sources associated with I-

type granite. Mineralogical and textural ( perthitic

texture ) characteristics alone to categorise I-type

granite.

ACKNOWLEDGEMENTS.

A Special thanks to jordanian natural resource authority

(NRA) for giving me the opportunity and support materials

to carry out this project.

REFERENCE

[1] Abdelsalam, M.G., Stern, R.J.,. Schandelmeier , H. and

Sultan, M. 1995. “Deformational history of the

Keraf Zone in northeast Sudan , revealed by shuttle

Imaging Radar” . Journal Geology 103: 475-491.

[2]

[3]

Al-Damegh, K., Sandvol, E., and Barazangi, M. 2005.

“Crustal structure of the Arabian Plate: New

constraints from the analysis of teleseismic receiver

functions”. Earth and Planetary Science Letters 231:

177-196.

Altherr, R., Holl, A., Hegner, E., Langer, C., Kreuzer,

H., 2000. “High potassium, calcalkaline I-type

plutonism in the European Variscides: northern Vosges

(France) and northern Schwarzwald (Germany)”.

Lithos 50: 51–73.

[4] Anderson, J.L., Morrison, J., 2005. “Ilmenite,

magnetite, and peraluminous Mesoproterozoic

anorogenic granites of Laurentia and Baltica”. Lithos

80: 45–60.

[5]

[6]

Avigad, D. and Gvirtzman, Z. 2009 . “Late

Neoproterozoic rise and fall of the northern Arabian-

Nubian Shield: The role of lithospheric mantle

delamination and subsequent thermal subsidence”.

Tectonophysics 477: 217-228.

Barker , F.,Arth.J.G.Peterman , Z.,E., and Friedman,

I.1976. The 1.7-1.8 billion years old trondhjemites of

southern Colorado and northern New Mexico;

Geochemistry and depths of genesis; Geological

Society of America Bulletin 87 : 189-198.

[7] Be’eri-Shlevin, Y., Katzir, Y., Whitehouse, M.J.

2009a.“Post-collisional tectonomagmatic evolution in



5786

the northern Arabian-Nubian Shield (ANS): time

constraints from ionprobe U-Pb dating of zircon”.

Journal Geological Society . London 166: 71–85.

[8] Be’eri-Shlevin, Y., Katzir, Y., Whitehouse, M.J., ,

2009b. “Post-collisional tectonomagmatic evolution in

the northern Arabian-Nubian Shield (ANS): time

constraints from ionprobe U-Pb dating of zircon”.

Journal Geological Society, London . 166: 71–85.

[9] Bentor, Y.K. 1985.“The crustal evolution of the

Arabo-Nubian Massif with special reference to the

Sinai Peninsular”. Precambrian Research 28 : 1-74.

[10] Beyth, M., Stern, R.J., Altherr, R., Kroner, A.

1994.“The Late Precambrian Timna igneous complex,

Southern Israel: Evidence for comagmatic-type

sanukitoid monzodiorite and alkali granite magma”.

Lithos. 31:103-124.

[11] Blasband, B., White, S., Brooijmans, P., De Boorder,

H., Visser, W. 2000.“Late Proterozoic extensional

collapse in the Arabian–Nubian shield”. Journal of Geological Society , London 157 : 615–628.

[12] Boynton, W.V. 1984. “Cosmochemistry of the rare

earth elements; meteorite studies. In: Rare earth element geochemistry”. Henderson, P. (Editors),

Elsevier Sci. Publ. Co., Amsterdam. 63-114.

[13] Bonin B, Azzouni-Sekkal A, Bussy F, Ferrag S. 1998.

“Alkali-calcic and alkaline post-orogenic (PO) granite

magmatism: petrologic constraints and geodynamic

settings”. Lithos 45: 45–70.

[14] Debon F, Le Fort P. 1983 . “A chemical–mineralogical classification of common plutonic rocks

and associations”. Transactions of the Royal Society of Edinburgh Earth Sciences 73: 135–149

[15]

[16]

El-Bialy, M.Z. and Streck, M.J. 2009. “Late

Neoproterozoic alkaline magmatism in the Arabian-

Nubian Shield: the postcollisional A-type granite of

Sahara-Umm Adawi pluton, Sinai, Egypt”. Arabian Journal of Geosciences 2 : 151-174.

El-Isa Z.H., Al Shanti A., 1984. “Seismicity and

tectonics of the Red Sea and western Arabia”,

Geophysical Journal International 97: 449-457.

[17]

[18]

Farahat, E.S., Mohamed, H.A., Ahmed, A.F. and El

Mahallawi, M.M. 2007. “Origin of I- and A-type

granitoids from the Eastern Desert of Egypt:

implications for crustal growth in the northern

Arabian–Nubian Shield”. Journal of African Earth Sciences 49 : 43–58.

Furnes, H., Thorseth, I.H.,Tumyr, O., Torsvik, T. and

Fisk. M.R. 1996. “Microbial activity in the alteration

of glass from pillow lavas from Hole 896A”. In;

Proceedings of the Ocean drilling program.Scientific results. College station, Texas 148: 191-206.

[19] Eyal, M., Bartov, Y., Shimron, A., Bentor, Y.K. 1980.

“Sinai— geological map (1:500,000)”. Survey of

Israel.

[20] Green, T.H. 1995.“Significance of Nb/Ta as an

indicator of geochemical processes in the crust-mantle

system”. Chemical Geology 120: 347–359.

[21] Greenwood, W.R. and Brown, G.F. 1973.“Petrology

and chemical analysis of selected plutonic rocks from

the Arabian Shield, Kingdom of Saudi Arabia”. Saudi

Arabian Dir. Gen. Mineral Resources Bull 9:9.

[22] Hargrove, U.S., Stern, R.J., Griffin, W.R., Johnson,

P.R., Abdelsalam, M.G. 2006a . “From Island Arc to

Craton: Timescales of Crustal Formation along the

Neoproterozoic Bi’r Umq Suture Zone”, Saudi Geological Survey, Kingdom of Saudi Arabia, pp.69.

[23] Harrison, T.M., Watson, E.B. 1984. “The behavior of

apatite during crustal anatexis: equilibrium and kinetic

considerations”. Geochim. Cosmochim 48, 1467–1477.

[24] Harris NBW , Pearce JA, Tindle AG. 1986.

“Geochemical characteristics of collision-zone

magmatism”. In: Coward MP, Alison C (eds) Collision

Tectonics. Geological Society London Special Publications 19 : 67–81.

[25] Hofmann, A.W. 1988. “Chemical differentiation of the

Earth. The relationship between mantle, continental

crust and oceanic crust”. Earth Planet of Science Letter. 90: 297–314.

[26] Huang, H., Niu, Y., Zhao, Z., Hei, H. and Zhu, D.

2011.“On the enigma of Nb-Ta and Zr-Hf

fractionation—a critical review”. Journal Earth Science 22:52–66.

[27] Ibrahim, K.M. and W.J. McCourt. 1995.

“Neoproterozoic granitic magmatism and tectonic

evolution of the northern Arabian Shield: Evidence

from southwest Jordan”. Journal of African Earth Sciences 20 : 103-118.

[28] Irvine T, Baragar W . 1971. “A guide to the chemical

classification of the common volcanic rocks”.

Canadian Journal of Earth Science 8: 523–548.

[29] Jarrar, G .H., Theye, T., Yaseen N., 2013.“Whitehouse

M., Pease V., and Passchier C. Geochemistry and P-T-t

evolution of the Abu-Barqa Metamorphic Suite, SW

Jordan, and implications for the tectonics of the

northern Arabian-Nubian Shield”. Precambrian Research 239: 56-78.

[30] Jarrar, G .H., Manton, W.I., Stern R.J. and Zachmann,

D. 2008. “Late Neoproterozoic A-type granites in the

northernmost Arabian-Nubian Shield formed by

fractionation of basaltic melts”. Chemie der Erde

68:295-312.

[31] Jarrar, G., Stern, R.J., Saffarini, G., and Al-Zubi, H.

2003. “Late-and post-orogenic Neoproterozoic

intrusions of Jordan: implications for crustal growth in

the northernmost segment of the East African Orogen”.

Precambrian Research 123: 295-319.

[32] Jarrar G.,H., 1985.“Late Proterozoic crustal evolution

of the Arabian Nubian Shield in the Wadi Araba area,

SW Jordan”.Geologische Jahrbuch Reihe B, Heft 61:

3-87.



5787

[33]

[34]

Jin, M.S., 1986. Ca, Na, K, Rb, Zr, Nb and Y

Abundances of the Cretaceous to Early Tertiary

Granitic Rocks in Southern Korea and Their Tectonic

Implications. Memoir for Prof. S.M. Lee 60th Birthday

195–209 .

Johnson, P. R. and Woldehaimanot, B.

2003.“Development of the Arabian-Nubian Shield:

Perspectives on Accretion and Deformation in the

Northern East African Orogen and the Assembly of

Gondwana”. Geological Society, London, Special

Publications 206 : 289-32.

[35] Kamber, B.S. and Collerson, K.D. 2000.“Role of

hidden subducted slabs in mantle depletion”. Chemical Geoloy 166 : 241–254.

[36] Kröner, A. 1985.“Ophiolites and the evolution of

tectonic boundaries in the Late Proterozoic Arabian-

Nubian Shield of northeast Africa and Arabia”.

Precambrian Research 27: 277-300.

[37] Liégeois, J.P. and Stern, R.J. 2010.“Sr–Nd isotopes

and the geochemistry of granite– gneiss complexes

from the Meatiq and Hafafit domes, Eastern, Desert,

Egypt: no evidence for pre-Neoproterozoic crust”.

Journal of African Earth Sciences 57: 31–40.

[38] Liégeois J-P, Navez, J., Hertogen, J and Blac k R.

1998.“Contrasting origin of post-collisional high-K

calc-alkaline and shoshonitic versus alkaline and

peralkaline granitoids. The use of sliding

normalization”. Lithos 45 : 1–28.

[39] Maniar, P.D. and Piccoli, P.M. 1989.“Tectonic

discrimination of granitoids”. Geological Society of America. Bulletin 101: 635–643.

[40] McCourt, W.J. and K. Ibrahim. 1990.“The geology,

geochemistry and tectonic setting of the granitic and

associated rocks in the Aqaba and Araba complexes of

southwest Jordan”. Geological Mapping Division

Bulletin 10, Geology Directorate, Natural Resources Authority, Amman.

[41] McCourt, W. and Ibrahim, K. 1990.“The Geology,

Geochemistry and Tectonic Setting of the Granite and

Associated Rocks in the Aqaba and Araba Complexes

of Southwest Jordan”. Geology Director, Natural Resources Authority, Amman. Bull. 10

[42] McCourt W., J., Rashdan , M., Ibrahim , K., Rabba , I.,

and Abelhamid , G. 1988. “A new geological

framework for late Proterozoic basement of SW

Jordan” (Abstract ), third Jordanian geological conference , Amman.

[43] Meert, J., G. 2003.“A synopsis of events related to the

assembly of eastern Gondwana”. Tectonophysics 362:

1-40.

[44] Middlemost, E.A.K. 1994.“Naming materials in the

magma-igneous rock system”. Earth Science review

37: 215–224.

[45] Morag, N., Avigad, D., Gerdes, E., Harlavan, Y.

2012.“1000–580 Ma crustal evolution in the Northern-

Arabian Shield revealed by U–Pb–Hf of detrital

zircons from late Neoproterozoic sediments (Elat area,

Israel)”. Precambrian Research 208–211: 197–212.

[46] Morag, N., Avigad, D., Gerdes, A., Belousova, E.,

Harlavan, Y. 2011.“Crustal evolution and recycling in

the northern Arabian–Nubian Shield: new perspectives

from zircon Lu– Hf and U–Pb systematics”.

Precambrian Research 186 : 101–116.

[47] Muller D, Groves DI. 1992.“Gochemical discriminate

different tectonic setting : a pilot study”. Mineralogy and petrology 46.

[48] Peccerillo, A., Taylor, S.R. 1976.“Geochemistry of

Eocene calcalkaline volcanic rocks from the

Kastasmonu area, north Turkey”. Contribution to Mineralogy and Petrology 58:63–81.

[49] Powell, J., Abed, A., and Jarrar, G. 2015. Ediacaran

Araba complex of Jordan; Geo Arabia –Middle Eas t

Petroleum. Geosciences 20 (1) : 99-156.

[50] Rabba, I., Ibrahim K. 1988. “Petrography of the

plutonic rocks of the Aqaba complex , Jordan”.

Natural Resource Authority Bulletin 9 : 1-86.

[51] Schandl, E.S., Gorton, M.P. 2002.“Application of high

field strength elements to discriminate tectonic settings

in VMS environments”. Economic Geology 97 (3) :

629-642

[52] Segev,A. 1987.“The age of the latest Precambrian

volcanism southern Israel, northeastern Sinai and

southwestern Jordan—a reevaluation”. Precambrian Res. 36: 277–285.

[53] Stein, M. and Goldstein, S.L. 1996.“From plume head

to continental lithosphere in the Arabian-Nubian

shield”. Nature 382: 773-778.

[54] Stern, R.J., and Johnson, P., 2010.“Continental

Lithosphere of the Arabian Plate: A Geologic,

Petrologic, and Geophysical Synthesis”. Earth Science Reviews 101: 29-67.

[55] Stoeser, D.B. and Frost, C.D. 2006. Nd, Pb, Sr and O

isotopic characterisation of Saudi Arabian Shield

terranes. Chemical Geology 226, pp.163-188.

[56] Stoeser, D.B. and Camp, V.E. 1985. “Pan African

microplate accretion of the Arabian Shield”.

Geological Society of American Bulletin 96 : 817-826.

[57] Sylvester PJ. 1989.“Post-collisional alkaline granites”.

Journal Geology 97: 261–280.

[58] Vail, J. R. 1985.“Pan-African (late Precambrian)

tectonic terrains and the reconstructions of the

Arabian-Nubian Shield”. Geology 13:839-842.

[59] Whalen, J.B., Currie, K.I. and Chappell, B.W.

1987.“A-type granites: geochemical characteristic,

discrimination and petrogenesis”. Contribution of Mineralogy and Petrology 95: 407–419.

Petrography and Geochemistry of Urf suite from Aqaba ... · Calc-alkaline granitoids (ca. 630–610...

Documents

Transcript of Petrography and Geochemistry of Urf suite from Aqaba ... · Calc-alkaline granitoids (ca. 630–610...