3 pages report about Primary and secondary faults of Najd Fault system

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i need a 3 single spaced pages report about :Primary
and secondary faults of Najd Fault system ( What are primary and
secondary faults, what types of faulting are present in each category
(i.e. primary and secondary faults ), give their names, location ,
attitude (i.e. strike-dip directions, and dip amount)…etc)
please note that my subject is a part of the outline i will attach so no need for conclusion only do an introplease use very simple language as i am not a geologist neither a native speakerplease show exactly the parts you used from the sourcesuse figures when neededan example of the work needed is also attached

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Tentative list of content: Najd Fault
Table of contents
1- Introduction (What is Fault, Najd, Najd Fault as a geological system?
What is the geography of this region (Najd) and surrounding areas,talk
generally about the geology of Najd, focus on Najd Fault in thesis
statement).
2- The regional geological setting (Large-scale geology: Najd fault system,
Najd Fault system and surrounding geological systems, talk in detail about
the geology of Najd Fault…etc).
3- The geochronology of the system (geological history of Najd Fault).
4- Stress analysis (types of stresses, direction of stresses, causes and effects
of stresses, past, present, and future scenario of stress field in Najd Fault,
give numerical details if possible…etc).
5- Deformational sequence and resultant structures (types of deformation
in Najd Fault, resultant geological structures from applied stresses on Najd
Fault, what geological structures are present in Najd Fault, give past,
present, and future scenario of geological structures in Najd Fault. Scale of
resultant structures: Micro-/Meso-/Macro-scopic…etc )
6- Primary and secondary faults of Najd Fault system ( What are primary
and secondary faults, what types of faulting are present in each category
(i.e. primary and secondary faults ), give their names, location , attitude
(i.e. strike-dip directions, and dip amount)…etc)
7- Mineralization (How minerals are formed in response to Najd Fault
formation, what type of minerals are present due to Najd Fault formation,
through which processes and under which circumstances did they
form…etc)
8- the associated sedimentary processes (The control of Najd fault on
sediments entrainment, transportation, deposition, burial. The name,
location, processes, scale of formation of resultant sedimentary systems or
regimes…etc)
9- Metamorphism related to Najd Fault (Type of metamorphism present
due to Najd Fault Formation, what are the P-T conditions of the types of
metamorphism, grade of metamorphism, types of metamorphic rocks
present, minerals of these rocks…etc)
10- Igneous activity related to Najd Fault (Types of igneous activities
present in Najd Fault, what are the igneous structures related to Najd Fault,
Types of igneous rocks present, minerals of these rocks…etc)
11- conclusion
1
Running head: MINERALIZATION OF NAJD FAULT
Introduction
The Najd Fault System belongs to the Arabian-Nubian Shield and is considered to be
earth’s largest Proterozoic Shear zone system. The zone of shear ceased to be active towards the
end of the Pan African evolution. This zone is said to be responsible for the excavation of
fragments of juvenile continental crust that leads to the development of basement domes which
transect the areas of Egypt and Saudi Arabia. A three-year study, funded by the Austrian Science
Fund (FWF) in collaboration with the Saudi Geological Survey (SGS) focuses on geochronology
and structural mapping of the shear zone system. It was conducted to help constrain the age and
mechanisms of digging up of the domes. There is a major difference between the basement
domes found in the desert regions of Egypt. Particularly, metaphoric rocks of the high grade are
not limited to basement domes which are surrounded by shear zones. They can also be found
within the shear zones.
MINERALIZATION OF NAJD FAULT
2
Cratonic Ore Provinces Separated by Continental Drift
It is expected that the fragmentation of the Arabian-Nubian Shield. This would
provide an exceptional possibility for the association of mineral districts in either part divided by
the fault has not been completed. This is because the lithologic -tectonic belts are almost parallel
to the Red Sea, although some similar to the ophiolitic and andesitic mineral relationships have
been proven to exist. Geologists believe that the North-South oriented auriferous zone that passes
from Ethiopia to Arabia fits best. The incomplete correlation may be attributed to the different
degrees of erosion. In this case, the Arabian Peninsula is higher than in Egypt. Also, the Red Sea
makes it easy for geologists to study the mineral deposits that result from incipient drift. Many
types of mineral deposits are similar on both sides of the Atlantic, an aspect that provides various
hints for prospecting. The level of the erosive process of the socle (base) and the lithological
surroundings influence the type of deposits that come from the first stages of rifting. Lead and
Barium (Pb-Ba) veins can be found in the basement. Lead and Zink (Pb-Zn) intrusion and
replacement deposits can be found in the platform cover. Sediments of Iron, Manganese and
Zink (Fe-Mn-Zn) can be found in the lake or marine basins. Alkali ring structures that are related
to Niobium and Tantalum (Nb-Ta) deposits share some similarities with the St. Lawrence rift
system. Deposits of Lead and Zink, which are similar in nature with those in the Red Sea region
can be found in the North Atlantic region.
Tectonics of the Najd Transcurrent Fault System and Minerals that were formed as a
result
The Arabian Shield is comprised of an assortment of meta-volcanic, Proterozoic
plutonic, and meta-sedimentary rocks. These were formed as a result of a series of
MINERALIZATION OF NAJD FAULT
3
sedimentation, intrusive activities, and volcanic action. They were later followed by a
deformation named by geologists as the Hijaz Orogenic Cycle. The Hijaz events reached their
peak after a dislocation of the complex was triggered by a strike-slip fault.
The regional alteration of the composition of rocks has led to the formation of mineral
accumulations of greenschist and amphibolite rock characters in several regions of the volcanosedimentary complex. The formation of greenschist occurs when the temperatures are low,
preferably between 300 to 450°C or 570 to 840°F. The formation pressures should also be low,
preferably between 2 and 10 kilobars or 14,500 and 58,000 psi. Greenschists is usually
composed of mostly green minerals such as epidote, chlorite, serpentine, muscovite, and platy
serpentine. Its texture can be defined as nematoblastic or schistose. Amphibolite, on the other
hand, is coarse-grained and is composed of black, green, or brown minerals. Both rocks were
formed as a result of the temperature and pressure generated as a result of two tectonic plates
converging. The result was a phenomenon known as metamorphism. In this case, they are
referred to as metaphoric rocks.
The Najd system of the lateral or transcurrent faults and associated secondary
structures travels across the NW-SE shield. As a result, it displaces the Hijaz igneous and
metaphoric rocks. The deformations of Najd were mostly brittle. However, there exists a piercing
MINERALIZATION OF NAJD FAULT
4
tectonic plate which is parallel to the fault zone found in the South East region of the shield
(Moore, 1979).
Igneous intrusions that came about as a result of the Najd plate tectonics lead to dyke
swarms and small plutons. The process of igneous intrusion develops when magma cools and
solidifies before it gets to the surface of the earth. These intrusions can be in the form of dykes,
sills, and batholiths. Most intrusions are usually rich in silica. Gravity plays a major role in how
the igneous rocks are formed and positioned. This is because it acts on the different densities of
the magma and the immediate rock surroundings (Moore, 1979). Generally, magmas that are rich
in silica are less dense than the surrounding rocks. Magmas that have poor silica levels have the
same density as the surrounding rocks. As a result, low-density intrusions appear to be different
from those of high densities. Magmas with low densities include those with granite. They are
more buoyant and make their surroundings subside. Magmas with high density are those with
basaltic components. They have a nearly equal hydrostatic equilibrium with the surrounding
rocks. When tested, the intrusions in the Najd Fault were found to be formed nearly 580 to 530
million years ago. The alkaline and calc-alkaline intrusions and basalt, andesite and rhyolite dyke
swarms have been displaced by the continuous fault movement that took place after localization.
Lavas are intercalated or inserted within the clastic rocks of the Jibalah Group.
Hydrothermal activity in the fault lead to the formation of small ore deposits such as
mineralized quartz veins. The hydrothermal process can be described as the physiochemical
process that is brought about by the movement of hydrothermal water found in the earth’s crust.
This is often as a result of magmatic intrusion or tectonic disturbance. Hydrothermal solutions
often originate from seawater or meteoric water that circulates within fractured rocks. They also
come from water that has been trapped within sediments during deposition (Lumen Candela,
MINERALIZATION OF NAJD FAULT
5
2009). The evidence of a widespread of igneous and hydrothermal activity shows that the zone in
which the fault occurred was an area of abnormally high heat transfer during the Proterozoic and
Ecocambian period and most probably during the Phanerozoic times. The fact that there is an
alternation in the hydrothermal activity proves that there is a mechanical importance in fluid
pressure. This phenomenon had a partial bearing in the process of fault formation.
Gold is also found in the Najd Fault system. In particular, the Mahd Adh Dhahab
region of Saudi Arabia has the largest deposit of the gold ore (Tahoun & Al-Shanti, 1979). Gold
is formed through several geological processes. They can be classified as alluvial, residual, or
primary deposits. Since the Najd Fault mainly comprised of intrusion activities, the gold formed
it is intrusive-related. It is mostly hosted by porphyry, granites, and at times dykes. It usually
contains copper and at times may contain traces of tungsten and tin. This form of gold mostly
relies on the presence of gold that is found in fluids within the magma (Lumen Candela, 2009).
There is a significant amount of polymetallic sulfide within the Saudi Arabian
Precambrian Shield. These can all be distinguished by their mineral association, texture, mode of
occurrence, and mineralogical characteristics. The first form of sulfide is lens-shaped that form
mineralized layers that have felsic pyroclastic sequences. The second form of sulfide appears like
a pipe-like stockwork. They occur within volcanistic accumulation of different colors. The third
form of sulfide is those which can be linked to quartz veins (Tahoun & Al-Shanti, 1979).
Sulfides are generally formed through the metaphoric process. The actual formation of sulfides
occurs when sulfates are broken down by high temperatures and pressures. In the process of
sedimentation, sulfide minerals come as a result of the reducing action of bacteria.
MINERALIZATION OF NAJD FAULT
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Table Showing Minerals and their Formations
Mineral
Mode of Formation
Silica
Intrusion
Calc-alkaline
Intrusion
Gold
Alluvial action or
Metamorphosis
Sulfide
Metamorphosis
Sulfide
sedimentation
Greenschist
Metamorphosis
Amphibolite
Metamorphosis
MINERALIZATION OF NAJD FAULT
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References
Website
Lumen Candela. (2009). Rock and Mineral Resources | Geology. Retrieved from
Lumenlearning.com website: https://courses.lumenlearning.com/wmopengeology/chapter/outcome-ore-and-mineral-resources/
Journal
Moore, J. M. (1979). Tectonics of the Najd Transcurrent Fault System, Saudi Arabia.
Journal of the Geological Society, 136(4), 441–452. https://doi.org/10.1144/gsjgs.136.4.0441
Book
Tahoun, S. A., & Al-Shanti, A. (1979). Evolution and mineralization of the ArabianNubian shield. Vol. 2. Oxford: Pergamon For The Institute Of Applied Geology, King Abdul
Aziz University, Aug.

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