Well yes, both Ras Koh and the Algerian site are granite mountains.That is similar geology.
Both are far from a large water body as waterbody absorbs shock.
Both are surrounded by desert.
So that is similar topography.
Similar? Oh really? They are very different regions, geologically speaking:
BALUCHISTAN BASIN
Few outcrops of Paleocene rocks are found in the
Baluchistan Basin, and subsurface information is
scarce. The greatest thickness of Paleocene rocks
shown on the isopach map (pi. 1) is in the northern
part of the basin, west of the town of Kharan Kalat.
Strata thicken abruptly northward in the Ras Koh
Range from 845 feet at Pakistan Standard Vacuum
Oil Company's section No. 173 to possibly 10,750
feet at Pakistan Tidewater Oil Company's section
No. 224. According to a Pakistan Tidewater Oil
Company report l this thickening of Paleocene strata
may be due to a fault, downthrown to the north,
where movement was contemporaneous with deposition.
On the basis of scanty and dubious data, it is
postulated that the Paleocene rocks that trend westward
throughout the southern part of Chagai District
(Kharan Kalat to the Iranian border) thicken
to the north; then, from approximately the central
part of the district, they thin rapidly toward the
Afghanistan border (R. H. Nagell, oral commun.,
1964). Additional work in this part of the Baluchistan
Basin is needed to show a more accurate picture
of the thickness of Paleocene rocks.
Southward from this thick sequence, Paleocene
rocks apparently thin to zero in the Central Makran
Range in the central part of the Baluchistan Basin.
Paleocene rocks crop out again farther south in at
least two isolated fault blocks in the Ispikan area,
west of the town of Turbat near the Iranian border.
It is inferred that Paleocene rocks thicken southward
from the Central Makran Range toward the
Makran coast of Pakistan, a region where younger
rocks crop out. This strongly suggests that the area
termed "Baluchistan Basin" is actually two basins
and that the term should be redefined. In this report,
however, the old usage is retained because of lack of
information need to accurately establish the actual
depositional basins present.
According to E. B. Fritz (oral commun., 1964),
the Paleocene fauna in the Khuzdar area of the
Kirthar depositional province is similar to the Paleocene
fauna in the Ispikan area. Fritz believes that
this similarity suggests that the Paleocene seas of
the Kirthar province were closely connected with
Paleocene seas of the Baluchistan Basin, probably
in the south.
The Baluchistan Basin is separated from the Indus
Basin by the central axis along which exposures
of Paleocene rocks seem to be absent because of erosion
or nondeposition. In the northern part of the
Baluchistan Basin, the Paleocene rocks are markedly
different from those in the Indus Basin. Clastic
ratios are very high, and the rocks contain beds of
volcanic material. Limited data indicate that the
clastic ratio increases northward. Little information
is available on clastic ratios in the southern part of
the Baluchistan Basin, except in the Ispikan area
where Paleocene rocks crop out in two fault blocks.
This scanty information indicates that the clastic
ratio increases southward. The northern and the
southern parts of the Baluchistan Basin are separated
by an area where Paleocene rocks apparently
are absent. This area, which bisects the Baluchistan
Basin, might be an expression of a western spur of
the central axis.
GEOLOGICAL SETTING OF THE CENTRAL
HOGGAR
As shown in Figure 1, three main lithologic
associations may be defined in Central Hoggar,
irrespective of their presumed age: (1) quartzo-
feldspathic gneisses and granites, (2) banded highgrade
metasediments including quartzites, marbles,
and metapelites, and (3) low-grade metavolcanics and
graywackes. The latter association, still undated, is
known as "Pharusian" and forms linear belts or small
basins presumed to be upper Proterozoic in age. In all
three lithologic associations the main metamorphic
foliation is more or less gently dipping, often
horizontal, and often associated with polyphased
recumbent folds [Bertrand, 1974; Latouche, 1978;
Vitel, 1979], except in the vicinity of the late wrench
faults and in some linear belts of upright north-south
trending folds.
Amongst the metasediments two groups have been
defined: (1) those intimately associated with the
quartzofeldspathic gneisses, the Arechchoum series,
and (2) the Aleksod series which lies in structural
unconformity upon group 1 and shows a simpler
structural history suggesting ayounger age.
The two groups are very similar in lithology, but in
the Aleksod area a set of basic dykes allows the clear
separation of the two groups [Bertrand, 1974]. In
places, stratigraphic unconformities are preserved, for
example, in the Toukmatine series in the Oumelalen
area [Latouche, 1978] and the Tazat area [Blaise,
1967; Bertrand et al., 1968], but tectonic contacts are
more usual. It was from the distinction of two groups
of metasediments and from the noncritical acceptance
of the "classical" Pharusian unconformity, which was
considered as giving a lower limit for the upper
Proterozoic, that the existence of a Kibaran event at
about 1000 Ma was previously proposed in Central
Hoggar [Bertrand, 1974]. Some geochronological
results seemed at that time to supporthis assumption
[Bertrand and Lasserre, 1976], but they were
discussed using data from other regions [La Boisse
and Lancelot, 1977]. In fact, recent structural
investigations in the schist belts have shown the
tectonic nature of the "classical" unconformity (M.
Briedj and J. M. Bertrand, unpublished observations,
1980).
Two major events have been recognized in Central
Hoggar using available geochronological data [Picciotto
et al., 1965; Latouche and Vidal, 1974;
Bertrand and Lasserre, 1976; Bertrand et al., 1978,
and 1984; Vialette and Vitel, 1979; Latouche and
Vidal, 1974]: (1) the Eburnean event at about
2000 Ma is defined from quartzofeldspathic
gneisses, including orthogneisses and charnockites,
and from the older metasediments and (2) the PanAfrican
event at about 600 Ma.
The metamorphic evolution of Central Hoggar
reflects the dual influences of the history of the
Suggaran (Eburnean) basement and of the PanAfrican
imprint. From their structure and radiometric
age, the granulitic assemblages and the prebasic dyke
gneisses are attributed to the Suggaran event
[Latouche, 1978; Vitel, 1979; Ouzegane, 1981]. The
tendency, in recent papers and theses, is to attribute
the intermediate pressure metamorphism, often
corresponding to the most conspicuous foliation, to a
Kibaran event, and the low-pressure metamorphism
to a thermal effect related to granite emplacement
during the Pan-African, the low-grade retrogression
being the result of late wrench faults and/or associated
upright north-south folding. From the point of view
of the plutonic evolution, no Kibaran age has ever
been found in any granitic body. In the In Amguel
region, Vitel [1979] has proposed a classification of
the Pan-African granitoids dated by the Rb/Sr
isochron method [Vialette and Vitel, 1979] from 670
+ 20 Ma to 514 + 20 Ma.
To summarize, a polycyclic evolution has been
recognized in Central Hoggar, but with the exception
of the granitoid emplacement and associated low
pressure metamorphism of evidently Pan-African age,
most of the tectonic and metamorphic evolution was
considered as older, belonging either to an Eburnean
or a hypothetical Kibaran event. The new observations
and data presented in the following
sections were initiated after the discovery of flat-lying
retrogressive mylonites contrasting with zones where
older structures are preserved [Boullier and Bertrand,
1981].
