TITLE:
Landforms Evolution of Wadi Qudaid Area, West Central Arabian Shield, Saudi Arabia: An Example of the Role of the Geological Factors in the Urban Extensions
AUTHORS:
Ali A. Mesaed, Mohammed A. M. Alghamdi, Abdullah R. Sonbul
KEYWORDS:
Wadi Qudaid, Geomorphology of Saudi Arabia, Landforms Evolution, Erosion Cycle, Urban Extensions
JOURNAL NAME:
Open Journal of Geology,
Vol.10 No.6,
June
16,
2020
ABSTRACT: Wadi Qudaid is located in
the west central part of Saudi Arabia. It about 135 km to the northeast of Jeddah city along Al Haramein
highway and it represents the upstream of the very large alluvial plain along
the Red Sea coast. It runs in NE direction parallel to many wadis of the west
central part of Saudi Arabia i.e. Wadi Fatima, wadi Sitarah. The wadi floor is filled by Quaternary deposits
which represent good groundwater aquifer. Geologically, the present-day
residual landforms of Wadi Qudaid are composed mainly of Precambrian Arabia
shield rocks overlained by Tertiary sedimentary rocks and finally harrat
(Tertiary volcanic). The Precambrian rocks are represented by 1) a lower
layered basic and intermediate volcanic and the intercalated volcaniclastics.
This unit is correlatable with Samran Group, 2) an upper layered acidic
volcanic and the intercalated acidic volcaniclastics. The Arabian shield rocks
are intensively folded and dragged along the major NE faults. They are directly
overlain by Tertiary basic volcanic (harrat) and the related volcanoclastic red
beds). The main geomorphologic elements of the study area include plateau, scarps, and the wadi floor. The plateau is
represented by the black basaltic sheet that contains some semi-rounded
depressions filled with Quaternary eolian sands. The scarps of the main wadi
and its tributaries are nearly steep and contain many asphaltic roads with some
isolated cone hills detached from the scarps. Geomorphological, Wadi Qudaid represents the incomplete erosion cycle that
begins with the formation of deep galleries and very steep and narrow wadies
formed along the major NE faults and related fractures and folds. The progress
of the erosion processes led to the formation of narrow interfluves as a result
of pedimentation and sculpturing of the wadies sides by scarp retreat. The
peniplanation stages of the erosion cycles are reached in the southwestern and
the central part of the wadi where fast peniplained areas were formed. The
results of this study revealed the role of the different geological processes
(lithology, structural elements and climatic conditions) in the distribution of
present-day human populations in urban extensions. Qudaid, Dhubaya-Jumah, Dabyah,
Al Khamrah, Almansa and Al Massamah are the main
villages of Wadi Qudaid area.