The increasing anthropogenic activities (e.g.,
constructing touristic resorts) have led to
notable changes in the Yemeni Red Sea coastal regions.
In this context, recent sediments have been investigated
to infer possible natural and man-induced processes on
these coastal areas. The target area lies between longitudes
43130–43300E and latitudes 13150–13550N. It
extends about 90 km along the coastline as a part of the
Tihama plain. Geomorphologically, it forms a longcurved
stretch with pronounced headlands, embayments
and bays. Generally, it is covered by recent sediments
(wadi, lagoon, beach and spit deposits along with sabkha,
coastal dunes and mangrove). Textural studies
reveal that most of the studied sediments are mainly
poorly to moderately sorted and are composed mainly of
sandy fractions with few gravel and mud, mostly
bimodal with minor unimodal patterns. The igneous
(granites) as well as basic (basalt, andesite and andesitic
pyroclastics) and acidic (dacite and rhyolite) volcanic
rocks of Tertiary age, which are exposed to the east of
the study area, are believed to be the source of pyroxenes,
amphiboles, epidotes, biotite, sphene, zircon,
tourmaline and rutile, in a decreasing order of abundance.
Moreover, smectite, kaolinite, chlorite, illite and
palygorskite are the predominant clay minerals, mainly
of detrital origin. The total carbonate content fluctuates
from 37.41% (lagoon sediments) to 53.74% (sabkha
sediments). The high amount of sea grasses, which
covers the tidal flat zone and relates to the fine-grained
sediments, accounts for the high organic matter content.
The mineralogy of the source rocks has controlled the
general distribution of major elements (Fe, Mg, Na, K
and Mn) in the beach sediments. In such sediments, the
concentrations of the heavy metals (Cu, Zn, Cd, Ni, Pb
and Co) may reflect the sediment pollution using different
approaches. The enrichment factors (EFs) of the
trace metals for most samples reveal values that are
greater than 1, referring to three groupings, which are:
moderate to moderately severe (Zn, Cu and Mn), minor
to moderate (Pb and Co) and zero to minor (Cd and Ni)
enrichment. The EFs for Pb, Cd, Ni and Co metals (5)
may be attributed to the crustal materials and/or natural
weathering processes. But, those for Zn, Cu and Mn
([5), especially in Al-Khowkhah–Abu-Zahr, Moushij–
Zahari–Ruays, Yokhtol and Mokha localities, are possible
of anthropogenic contributions.