الفهرس 
’GENERAL GEOLOGIC SETTINGOnly 14 pages are availabe for public view
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Abstract
The present study is devoted fo::: the treatment and
interpretation of the available geophysical data, utilizing
the Boligller gravity data and the total ~ntens~ty land
magnetic data, of the northwestern part of 1:he Sinai
peninsula, Egypt. Northward of lat~tade 30° alternating
faulted domes, anticlines and synclines known as tbe Syrian
arc system form a contrasting topog:::a:;:hy of lew alluvial
plains and high hill masses. Norther:o.
sediments predominantly deposited in
environment.
Sinai is covered by
a shallow platfo~
T~e Bouguer g=avity nap of ~~e studied area is
interpreted in orde= to define the ve~t.ical ar.d lateral
variations in the stratigraphy and structure of the
sedi~entary section. First, the isolation cf the residual and
regional anomalies is done on the Bouguer gravity nap, using
Griffin’s method (1949). However, the residual gravity
anomalies reflected the anomalies that result from shallow
sources, but the regional gravity anomalies revealed the
effects that produce from relatively deeper sources.
In addition, filtering of the Bouguer gravity anomalies
is also operated using regional filters, residual filters and
band-pass filters. The regional filters passed long
wavelengths of the regional anomalies of deep scl:rces with
low frequencies and rejected all wavelengths smaller than the cut-off wavelength (Low-pass-filter). The residual filters
passe~--s~o_rt __ wave~=ng:t~ _o_f _ ~[1_., ___ J,ccaJ, anomalies c:r: !>h~ll.91.’
sources with high frequencies and rejected al:. the
wavelengths larger than the cut:-off wavelength (high-pass
filter). The band-pass filter passed wavelengths within a
eeztai:ii range and reJected the wavelengths shorter than the
lower cut-off limit and longer than the upper cut-off limit.
’Ynis is done utilizing the filter operators 8-unit, 16-unit
an 21.3 unit with the ranges betNeen then (16-B, 21.3-16 and
21.3-8 units).
On the other hand, the importance and relationship of
gravity anomalies (including the opt in= filtered residual,
regional and band-pass gravity anomalies, as well as local
a~d regional geologic condi~ions) are ~e:l-shcw~ ty ~~e five
different orientation gravity pr·ofi:es. These pr:::files are
interpreted ttuough the two-di~ensional complex gravity
Modelling to constr~ct the subsurface structural pattern
along them. Moreover, the gravity structures are delineated
within the sedimentary section, as ·well as the underlying
basement complex in the form of fault segments (elements) at
different depths using Linsser’s method (1967). However, the
systems of faulting dissecting the whole sediment:ary colllifu~,
as well as those intervening the depth ranges of 2.0,3.0,4.0
and 5.0 kms are defined with respect to their trends, throws,
effects and coincidence.
Finally/ the predomi~ant st~4ct~ra: ~re~ds of the faul~
ele:nents, which delineated fron the gravi -:.y detailing are as follows:
- NE-SW (ENE) trend (Syrian arc system).
·· ·~-m;=:;E ~·end - ·(Re-a-s-ea sys~emT;
E-W (WNW) trend (Mediterranean sea system).
NNE-SSW trend (Aqaba system) .
Al.so, the land survey of the total intensity magnetic
----and Geophysies is analyzed in ter:ns -cf·· basewei,~ · pa!. ameler.
First, this total intensity land magnetic map of the studied
area is reduced to the pole to eliminate the distortions
occurred in the distribution of ~~e exis~ed magnetic
anomalies due the . ., . ~.
l.nC..~...l.na .... .l.on of the measured nor:nal
magnetic field. Then, the separation of t!:le residual and
regional anomalies is done on both the total intensity land
magnetic data and the reduced to 1:!:le J:agnetic pole data
utilizing Griffin’s method (1949). The two residual maps and
the two regional maps are generally si:nilar, but the :naps
derived from the reduced to the pole data are shifted
northward with more resolution, as ccnpared with the maps
derived from the total intensity land magnetic map.
On the other hand, filtering of the total intensity
magnetic and the reduced to the pole anomalies is also
operated utilizing the same filters, which were used before
in the treatment of the gravity anonalies. By the same way,
this proved to be helpful in isolating ~~e residual anomalies
from the regional ones from the anonalies existed within
a certain interval of depth. Moreove:::-, the application of these filters and their operators on the st~died gravity and
magnetic data reveals that; the 8-unit residual fil~er is the
cptim= for delineating the $ID3.ller ele::~ents of shallow
depths on the expense of the 16 and 21. 3 units; the 21. 3
regional filter is the best for defining the larger elements
of deep dep~hs on the emense of tbe----8 and 16 units A) Si 1 1
the 21.3-8 band-pass filter is tJJ.e adequate for following the
inferences of ~n~ermedlate depth range on the expense of the
16-8 and 21.3-16 units.
Added, the parameters (depth, -wi::J.t:: and azimuth) of the
dyke system intervening the basenent su~face of the
investigated area are deternined usi:1g C::urant’:1y and drys
(1963) and powell (1956&1967) techni~~es. Accordingly, a
basement relief :n.ap wi t:r.. the nar.:..::es-:.ed dykes is dra~wn,
showing more or less the configuration of the basement
surface in the area and the related igneous activities.
Therefore, the basement of such area is characterized by a
swell trending NNW-SSE at the central part, changed at the
northern part to be nearly NE-SW t!:”er’.d, :.n addition, ”three
troughs trending NNE-SSW at the eastern part, NW-SE at the
sout..>J.western corner and E-W at the northern part.
The inspection of the regional and residual gravity and
magnetic anomalies as well as the results of application of
the other interpretational methods on the potential field
data ::-eveals the subdi visicn cf the i:1vestigateC . ~ area .:.n ..... o
normal fault t~xowing westward. The eastern portion with two Jnonnal
faults t~cwing out·t~ard.ly rep::=-ese:-1--:.s a harst block
implicated by Gifgafa and Maghara an~ic:inal trends, as well
as El-Laga::na and El-Hassana syncl.:..r.a: t~ends, all nearly
directing ENE-WSW. Alsc;-, o-c.her
normal faults -chrowing inwardly represenc:s a graben block
manifested by Gilbana and El-KantaTa anticlinal trends as
well as El-Abd and lsmalJ.a s:r-nclJ.nal -.:rendS, all nearly
implied ty the longitudinal ~ina-El Barda•il Synclinal trend