This facies belt includes one petrofacies and five microfacies. A1 is an evaporite microfacies, A2-A5 are carbonate microfacies and A6 is a siliciclastic petrofacies. These petrofacies and microfacies are deposited in supertidal and intertidal subenvironments, described as follow:

A₁: Gypsiferous Mudstone

This microfacies consists of 30% gypsum crystals with less than 0.1 mm in size, scattered in a micritic matrix (Figure 4(a)).

A₂: Evaporites Dolomudstone

This microfacies includes gypsum evaporite dolomudstone (Figure 4(b)).

A₃: Dolomitized Fenestral Stromatolite Boundstone

This microfacies consists of 50% cyanobacteria algae and Bird’s-eye and fenestral fabric. Cyanobacteria algae can be found in laminated and boundstone form. It is noteworthy that dolomitization can also occur in this microfacies (Figure 4(c)).

A₄: Fenestral Mudstone

This microfacies, lacking allochem, is a dolomitized fenestral or bird’s-eye mudstone, interbeded in a limemud matrix (Figure 4(d)).

A₅: Fenestral Intraclast Algal Packstone

This microfacies is made up of 65% cyanobacteria algae, 20% intraclast and fenestral and bird’s-eye fabric, interbeded in a lime mud matrix. The average size of the grains is reported to be 0.2 mm (Figure 4(e)).

A₆: Quartzarenite

This petrofacies contains more than 95% 0.5 mm-sized, mature, relatively well-rounded and well-sorted grains and quartzarenite petrofacies (Figure 4(f)).

Microfacies and petrofacies in tidal flat environment are formed in the semi-arid to arid supertidal and intertidal subenvironments. Microfacies A₁, a mudstone filled with abundant evaporite minerals and interlayered with gypsum, points to the deposition of this microfacies within supratidal subenvironment [13] [14] and hot and humid climate [15] .

Due to the intermediate environment of the facies formation, their deposits are moved out of water regularly and irregularly and show certain characteristics, among which one can point to the gypsum crystals, likely formed in the supratidal or Sabkha subenvironment. Todays, these evaporite minerals can be found in supratidal environment is Texas or southern coastlines of Persian Gulf and Mediterranean Sea [16] - [18] . Presence of these minerals suggests an average temperature of higher than 22˚C and a seasonal temperature of more than 35˚C [10] .

Gypsum crystals are formed in supratidal subenvironment as a result of the high evaporation, resulting in absorbing calcium and creating fine-crystal dolomitic dolomicrite [16] [19] . Microfacies A₂, as a fine-crystal dolomite or dolomicrite, is known as type 1 dolomite. The size of crystals in these dolomites is about 5 - 6 microns and is usually formed within supratidal subenvironment due to its fine crystals, maintaining its original texture and lack of fossil. These types of dolomites are called secondary dolomites, formed in the early stages of diagenesis. Sea water and interparticle solutions saturated with Mg are reported to be the likely causes of dolomitization [20] . Mudstone is formed as a primary dolomite (Sabkha) in the supratidal subenvironment (dolomicrite) after formation of evaporite minerals due to the exit of sulfate ions from environment [21] .

Fenestral fabric is formed as a result of dehydration and burrowing activities of worms and insects and extended within microfacies A₃-A₅ [13] [14] . Microfacies A₃ consists of stromatolitic bands and laminations. Laminated algal structures are mostly preserved within highly salty supratidal to intertidal flat restricted subenvironments because of the environmental dangers and abundance of deposit feeders and grazing animals, particularly gastropods. This can be proven with respect to the presence of these microfacies within evaporite deposits and the presence of evaporite crystals in the dolomitic laminations of stromatolites [13] [14] . Lack of biological variation in microfacies A₄ points to the lack of appropriate ecological conditions for marine life [22] - [24] . The presence of fenestral fabric and intraclasts in microfacies A₅ confirms that this microfacies has been formed within upper intertidal subenvironment. Petrofacies A₆ shows the high energy condition in lower intertidal subenvironment. The presence of iron oxide accounts for the abundance of dissolved oxygen, which in turn confirms the shallowness of this subenvironment [8] [25] . Moreover, mature quartzarenite petrofacies is a sign of high flow regimes of intertidal subenvironment [26] .

This facies belt is composed of three microfacies as follow:

B₁: Sandy Mudstone

This microfacies is made up of 10% 0.1 mm-sized quartz grains and a small amount of bioclasts, located in a limemud matrix (Figure 5(a)).

B₂: Pellet Intraclast Pelecypoda Wackstone

The most abundant allochems of this microfacies are 15% 0.6 mm-sized pelecypoda fragments, together with 10% 0.2 mm-sized intraclast and 5% 0.1 mm-sized pellet, located in a micritic matrix (Figure 5(b)).

B₃: Dolomitized Sandy Intraclast Pelecypoda Gastropod Packstone

This microfacies consists of 35% gastropods with 2 mm in size, 25% pelecypoda with 1 mm in size, 10% intraclast with 0.3 mm in size and 5% well-sorted and relatively rounded quartz grains in 0.4 mm, all lain within a micritic matrix. It is noteworthy that dolomitization also occurs in this microfacies (Figure 5(c)).

Microfacies of this facies belt share such characteristics as presence of lime mud, non-skeletal grains including pellet, intraclasts and lagoonal bioclasts such as pelecypoda and gastropod, capable of surviving in restricted and semi-restricted conditions [27] . The first common characteristics among microfacies of restricted lagoon environment is the presence of tranquility in their formation environment, and the second one is the high level of salinity in the depositional environment of the sediments of this group [24] . The distinctive feature of the microfacies of this group is due to the fabric type and grain size. Lagoon and basins separated from sea by shoal usually show restricted water circulation and have low salinity. The dominant form of deposit in this environment is carbonate, made up mostly of pellet [8] . High amount of quartz grains in microfacies B₁ indicates that this microfacies belongs to shallow lagoon environment [24] . According to the extension of lagoonal fauna and development of micritization in microfacies B₂ and B₃, one can associate these microfacies with lagoon environment [10] [11] . The presence of fecal pellets below the wackstone microfacies B₂ accounts for the enough oxygen and appropriate nutritional condition [11] . Due to the changes in salinity and freshwater inflows in microfacies B₃, the variety of stenohalines is reduced, and appropriate environment and conditions are prepared for the growth of euryhalines such as gastropods and pelecypoda [28] . Survival and preservation of gastropod in these deposits are attributed to low erosion and movement, implying an oxidized, low-energy restricted lagoon environment [14] [29] .

This facies belt consists of six microfacies as follow:

C₁: Cortoid Grainstone

The major allochems of this microfacies are 1 mm-sized micritic bioclast fragments, laid down in a sparry calcite cement matrix, and constitute 65% of the whole sample (Figure 6(a)).

C₂: Dolomitized Bioclast Grainstone

This microfacies consists of 40% crinoid, 20% brachiopod and 15% gastropod with size of 1 mm, situated in a sparry calcite cement matrix. Also, this microfacies has been influenced by dolomitization process (Figure 6(b)).

C₃: Dolomitized Framestone

The most important allochem of this microfacies is 70% 6 mm-sized corals. This microfacies have undergone dolomitization process (Figure 6(c)).

C₄: Crinoid Grainstone

This microfacies is composed of 90% crinoids with 0.5 mm in size, dominating a sparry calcite cement matrix (Figure 6(d)).

C₅: intraclast Algal Grainstone

This microfacies is made up of 45% tubiphyte algae with size of 1.5 mm and 20% intraclast with 0.4 mm in size, laid down within a sparry calcite cement matrix (Figure 6(e)).

C₆: Brachiopod Crinoid Grainstone

This microfacies contains 65% crinoids and 20% brachiopods with 1 mm in size, scattered in a sparry calcite cement (Figure 6(f)).

This facies belt is formed in shoal environment and below the wave effect due to the presence of skeletal fragments such as crinoid, corals and brachiopod and non-skeletal fragments like intraclast as well as lack of intergranular lime mud [30] . The presence of fully cement matrix, lack of lime mud and size of the grains forming

these microfacies indicate the high level of energy during the formation of this microfacies in a shoal environment [31] - [33] . Microfacies C₁, as a cortoid grainstone, is mostly covered by micrite. According to Flugel [11] , the micritic coverage of the skeletal grains indicate deposition in the area of light influence and depth of lower than 100 - 200 m. The presence of stenohalins like crinoid and brachiopod in microfacies C₂, C₄ and C₆ points to the association of these microfacies with open marine environment [34] . Lack of a continuous layer of coral and reef in microfacies C₃ accounts for the presence of pach reef. Since coral structures in carbonate ramps are found in the pach form, they are formed in leeward shoal and lagoon environments [11] and located above the normal waves level [8] . The presence of grainstone and intraclasts in microfacies C₅ points to its formation in a high- energy environment like shoal environment [11] . According to the evidence, this microfacies can be associated with the seaward shoal [10] [11] [35] [36] .

This facies belt is composed of three microfacies as follow:

D₁: Sandy Crinoid wackstone

This microfacies includes 15% 1-mm sized crinoid, located in a micritic matrix. Additionally, it contains 5% well-sorted and poorly rounded quartz grains with less than 0.1 mm in size (Figure 7(a)).

D₂: Dolomitized Crinoid Bryozoan Packstone

This microfacies involve 60% bryozoan and 15% 1 mm-sized crinoid, laid down in a micritic matrix. This microfacies is also influenced by dolomitization (Figure 7(b)).

D₃: Dolomitized Sandy Brachiopod Crinoid Packstone

This microfacies is made up of 60% crinoids, 20% brachiopod and 5% well sorted and rounded quarts with 0.6 mm in size, located within a micritic matrix. These microfacies experience dolomitization (Figure 7(c)).

The intergranular muddy matrix [37] and abundance of crinoids, brachiopods and bryozoan [8] point to the formation of microfacies D₁-D₃ in a low-energy and calm environment like open marine [37] . Regarding the

abundance of stenohalins like crinoids and brachipods, this microfacies is formed in a normal saline environment like open marine [11] [14] [38] . Abundance of carbonate mud and reduction in the skeletal fragments size in microfacies D₁ suggest the deposition of this microfacies in deep and low-energy open marine environment [11] . The amount of allochems is increased in microfacies D₂ and D₃ while the amount of micrite is decreased. The presence of cement and large volume of bioclasts like bryozoan and crinoids indicate that these microfacies are formed in shallow and high-energy like upper open marine environment [11] .

As a siliciclastic-carbonate sequence, this 129 m-thick depositional sequence is both overlain and underlain by type 1 sequence boundary. In this sequence, LST system tract unconformably overlies Kalmard formation by extending microfacies of supratidal subenvironment. In this depositional sequence, this LST system tract consists of early LST and late LST. Early LST contains microfacies of tidal flat environment (intertidal subenvironment) such as gypsiferous mudstone and evaporite dolomicrite and siliciclastic petrofacies of tidal flat environment (supratidal subenvironment) like quartzarenite, mostly observed in the desert as white gypsy marl and a sequence of thick-to-medium bedded red sandstone and thick-to-medium bedded yellow dolomite (Figure 9). Late LST is composed of horizontally stratified, medium-bedded sandstones, enjoying quartzarenite petrofacies with progradational stacking pattern. It is possible for this system tract to be formed during a sea level fall. LST system track is 15 m thick in the desert. One of the consequences of LST in carbonate-siliciclastic systems is the extension of siliciclastic deposits. Once sea level is lower than the edge of the continental shelf, more siliciclastic materials enter the environment [45] . Overlying LST system tract, TS is identified by medium bedded layers of sandy dolomitic limestone with lagoon microfacies (sandy mudstone).

TST system tract, showing deepening trend with retrogradational stacking pattern, consists of carbonate parasequences with tidal flat microfacies (intertidal) (fenestral mudstone), lagoon microfacies (sandy mudstone, Pellet Intraclast Pelecypoda Wackstone, Dolomitized Sandy Intraclast Pelecypoda Gastropod Packstone), shoal microfacies (Crinoid Grainstone, brochipod crinoid grainstone) and open marine microfacies (Sandy Crinoid wackstone and Dolomitized Sandy Brachiopod Crinoid Packstone). This system tract is observable in the desert in terms of a sequence of thick-to-thin bedded dolomitic sandstone and gray dolomitic limestone with horizontally stratified and 64.5 m in thickness. This system tract is progradationally followed by maximum flooding surface (MFS), identified by sandy crinoidal wackstone microfacies of open marine environment. This surface, preceded by TST system tract, is characterized by horizontally stratified, thin-bedded dolomitic limestone. HST system tract, exhibiting a shallowing trend with progradational stacking pattern, contains open marine, shoal, lagoonal and tidal flat microfacies. This system tracts is characterized by horizontally stratified, thick-to-thin bedded, dark gray dolomitic limestone with 49.5 m in thickness and consists of open marine microfacies (Dolomitized Crinoid Bryozoan Packstone), shoal microfacies (Dolimitized Crinoid Grainstone and Dolomitized Framestone), lagoonal microfacies (Pellet Interclast Pelecypod Wackestone and Sandy Mudstone) and tidal flat microfacies (Dolomitized Fenestral Stromatolite Boundstone). This sequence finally ends in SB1, characterized

by gypsiferous mudstone microfacies of supratidal subenvironment (Figures 10-12).

This 44 m-thick depositional sequence covers the first depositional sequence by type 1 sequence boundary. In this sequence, LST system tract immediately overlies SB1, and tidal flat microfacies are deposited due to the fall in sea level. These microfacies include gypsiferous mudstone and evaporite dolomudstone in supratidal subenvironment while it contains fenestral intraclast algal packstone and fenestral mudstone in intratidal subenvironment. This depositional system tract can be found in the desert in terms of a sequence of dolomite, shale and horizontally stratified, medium-to-thin bedded, yellow to green gypsy marl with 30 m in thickness (Figure 9). TS has progradationally overlain LST system tract and is characterized by thick-bedded, gray limestone and shoal microfacies (intraclast algal grainstone).

TST system tract, showing deepening trend with retrogradational stacking pattern, consists of carbonate parasequences of lagoon environment (Dolomitized Sandy Intraclast Pelecypoda Gastropod Packstone) and shoal environment (intraclast algal grainstone). TST has 9 m thickness and is observed as a horizontally stratified, thick-to-thin bedded, gray limestone. Next, MFS can also be found and is characterized by dolomitized sandy brachiopod crinoid packstone. It follows TST system tract and can be observed within horizontally stratified, thin-bedded, gray limestones. HST system tract, showing deepening trend with progradational stacking pattern, consists of shoal microfacies (dolomitized bioclast grainstone) and is characterized by horizontally stratified, medium-to-thin bedded, gray limestone with thickness of 5m. This sequence is overlain by SB1, identified by quartzarenite petrofacies of intertidal subenvironment (Figure 12).

This depositional sequence is 25 m thick and covers the second depositional sequence by type 1 sequence boundary. In this sequence, LST system tract immediately overlies SB1, and siliciclastic petrofacies (Quartzarenite) of tidal flat environment (intertidal subenvironment), showing progradational stacking pattern, is laid due to the fall in sea level. This depositional system tract can be found in the desert in terms of horizontally stratified, thick-to-medium bedded, reddish bioturbated sandstones with 7 m in thickness (Figure 9). TS and MFS are comply and have progradationally overlain LST system tract and are characterized by dolomitized crinoid bryozoan packstone and can be found in desert as a horizontally stratified thin-bedded, gray limestone.

HST system tract, showing deepening trend with progradational stacking pattern, is characterized in desert by horizontally stratified, thick-to-thin bedded gray limestone with thickness of 18 m and consists of open marine environment (dolomitized crinoid bryozoan packstone), shoal environment (cortoid grainstone), lagoon environment (Dolomitized Sandy Intraclast Pelecypoda Gastropod Packstone) and tidal flat environment (fenestral mudstone). This sequence finally ends in SB1, containing eroded red lateritic sandstone. These sandstones are associated with Chili formation (lower Permian), unconformably overlain Gachal formation in Madbeiki section (Figure 12).