Tidal flat rocks and sediments along the eastern coast of the United Arab Emirates

Abstract

The geomorphologic and petrographiccharacteristicsof the calcareoushard rocks in the intertidal and supratidal zones of the eastern coast of the United Arab Emirates,where it faces the Gulf of Oman, were investigated. The tidal zone can be broadly classifiedinto two major physiographicprovinces. A northernprovince that hasa rather steep profile and a tidal flat that is very narrow and is characterized by lithoclastsof gravelly sand sediments. It is formed of beachrocks, well-developedcoastal terraces and cliffs and is bounded landward by mountainscomposed mainly of peridotite and gabbros. The southem provincetidal flat is much wider thanthe north province with a shallow, tide dominated and sheltered coast where sandy bioclasts accumulate. The mountains surroundingsuch areas are located severalkilometers from the coast and are largely formed by gabbros.Beachrocks are developed as discontinuous beds in narrow belts of pavement, limited essentially to the intertidal zone and with a surface, which is generallysloping seaward. These rocks are partly covered by beach sand, skeletal debris, algae and other rock fragmentsencrusted by living organisms. They rest on dense to friable loose beach sand mainly composed of biogenic fragments strongly bonded by carbonate cements. Tidal terraces are almost flat benches that vary in their geomorphologic pattern and three well-developed terraces are recognized. Based on the composition of framework grains, beachrocks can be grouped into two types: lithic and bioclastic. The lithoclasts are mainly composed of peridotite, gabbros, pyroxenes, calcareous rock fragments and washed sediments derived from wadi-fill and dust storms. The bioclastic sediments are chiefly fragmentsof corals,foraminifera,pelecypods,gastropods,crabs, echnoidsand algae. The beachrockcement is mainly formed by aragonite, micrite and coarsely crystalline calcite with a subordinate amount of dolomite. Precipitation of aragonite appears to be mainly controlled by the micrite substrate and at least three successive stages of cement fill are observed.

Palaeocology of Hard Substrate Faunas from the Cretaceous Qahlah Formation of the Oman Mountains

“…1), and numerous truncation surfaces support, for this locality at least, the deltaic and tidal-channel models of Skelton et al (1990) and Smith et al (1995), with the sediments almost certainly derived from an adjacent high-relief ophiolitic coastline in the manner described by Alsharhan and Nasir (1996). This depositional system is at least partly analogous to the present deposition of ophiolite debris from cliffs in the shallow, subtropical Gulf of Oman on the eastern side of the Musandem Peninsula (see El-Sayed 1999). It is also a rocky-shore environment in the sense of Johnson (1988).…”

Environmental Characterization of Global Sources of Atmospheric Soil Dust Identified With the Nimbus 7 Total Ozone Mapping Spectrometer (Toms) Absorbing Aerosol Product

“…This region has no prominent morphological features (e.g., sand fields, large wadis, etc). It is a geologically recent tidal flat, wider in the south and southwest (up to ∼ 30 km wide), covered by sandy calcareous sediments and evaporites, the classic coastal sabkha [ Evans et al , 1964; Satchell et al , 1981; El‐Sayed , 1999]. In contrast to the other dust sources that we have identified thus far, most of the sediments originated from in situ or coastal processes not from fluvial deposits carried from higher elevations [ Evans et al , 1964].…”

Environmental Assessment of Heavy Metals Contamination of Bottom Sediments of Oman Gulf, United Arab Emirates

“…The values of PLI obtained in studied sediments. Table 3 show a different range of PLI from 0.59 of Dibba area to 1.93 of Kohr Kalba with average (1.23) indicating of semi polluted grade [22][23][24][25][26][27].…”