FIGURE 1 - uploaded by Mohamed Abdelghany Khalifa
Content may be subject to copyright.
Location map showing the studied sections of the Triassic- Jurassic rocks in Sudan, Egypt, Jordan and Saudi Arabia.
Source publication
The facies changes, tectonics and magmatism across the Triassic-Jurassic boundary in the southern Tethyan margin have been studied in Egypt, Sudan, Jordan and Saudi Arabia. In Saudi Arabia and Jordan an unconformable contact is recognized between the Upper Triassic and Lower Jurassic rocks. This unconformity surface is marked by the truncation of t...
Contexts in source publication
Context 1
... of the five largest extinction events of the Phanerozoic, (Sepkoski, 1996; Hallam and Wignall, 1997; Hallam, 2002), the Triassic– Jurassic boundary has been studied by different authors in different localities all over the world. For example, the stratigraphy of the Triassic-Jurassic boundary in Europe has been well-studied in southern Swe- den and northwest of Poland (Bertelson, 1978), in the Northern Calcareous Alps of Austria (Satterley et al., 1994) and in England (Hallam, 1990, 1995). Pronounced facies changes across the Triassic-Jurassic boundary have been studied in Nevada, USA (Hallam and Wignall, 2000), in southern Tibet (Hallam et al., 2000) and in Hungary (Haas and Tardt- Filacz, 2004). Hallam and Wignall (1999) mentioned that the contact between the Triassic and Jurassic in Africa and Asia is generally poorly known because of a paucity or absence of marine successions across the boundary. The present study presents good evidence for the unconformable relationship between the fluvial and fluvio-marine facies of the uppermost Triassic and lowermost Jurassic on the shelf area in Egypt and Sudan (northeast Africa), Jordan, and Saudi Arabia (southwest Asia) (Fig. 1). However, the recognition of the Triassic-Jurassic boundary in Sudan is difficult because the facies around the boundary are represented by coarse clastics. Well-exposed sections and subsurface data in other studied localities provide a good opportunity to contribute a better un- derstanding about the facies changes, tectonics, and volcanism across the Triassic-Jurassic contact. The Triassic rocks in Egypt were studied in the subsurface in the Western Desert, while the exposed Triassic-Jurassic rocks are measured in Northern Galala (north Eastern Desert) and in western and central Sinai (Fig. 1). On the Arabian Peninsula, the Triassic–Jurassic rocks were examined east of the Dead Sea rift at Jordan and Al Mustawi area (Al Qasim Province), Saudi Arabia (Fig. 1). The aim of this study is to explain the facies architecture across the Triassic-Jurassic boundary in Egypt, Sudan, Jordan and in Saudi Arabia and to clarify the nature of the contact at the Triassic–Jurassic boundary. Also, this study aims to determine the factors responsible for the unconformable contact and major gap between the two ...
Context 2
... of the five largest extinction events of the Phanerozoic, (Sepkoski, 1996; Hallam and Wignall, 1997; Hallam, 2002), the Triassic– Jurassic boundary has been studied by different authors in different localities all over the world. For example, the stratigraphy of the Triassic-Jurassic boundary in Europe has been well-studied in southern Swe- den and northwest of Poland (Bertelson, 1978), in the Northern Calcareous Alps of Austria (Satterley et al., 1994) and in England (Hallam, 1990, 1995). Pronounced facies changes across the Triassic-Jurassic boundary have been studied in Nevada, USA (Hallam and Wignall, 2000), in southern Tibet (Hallam et al., 2000) and in Hungary (Haas and Tardt- Filacz, 2004). Hallam and Wignall (1999) mentioned that the contact between the Triassic and Jurassic in Africa and Asia is generally poorly known because of a paucity or absence of marine successions across the boundary. The present study presents good evidence for the unconformable relationship between the fluvial and fluvio-marine facies of the uppermost Triassic and lowermost Jurassic on the shelf area in Egypt and Sudan (northeast Africa), Jordan, and Saudi Arabia (southwest Asia) (Fig. 1). However, the recognition of the Triassic-Jurassic boundary in Sudan is difficult because the facies around the boundary are represented by coarse clastics. Well-exposed sections and subsurface data in other studied localities provide a good opportunity to contribute a better un- derstanding about the facies changes, tectonics, and volcanism across the Triassic-Jurassic contact. The Triassic rocks in Egypt were studied in the subsurface in the Western Desert, while the exposed Triassic-Jurassic rocks are measured in Northern Galala (north Eastern Desert) and in western and central Sinai (Fig. 1). On the Arabian Peninsula, the Triassic–Jurassic rocks were examined east of the Dead Sea rift at Jordan and Al Mustawi area (Al Qasim Province), Saudi Arabia (Fig. 1). The aim of this study is to explain the facies architecture across the Triassic-Jurassic boundary in Egypt, Sudan, Jordan and in Saudi Arabia and to clarify the nature of the contact at the Triassic–Jurassic boundary. Also, this study aims to determine the factors responsible for the unconformable contact and major gap between the two ...
Context 3
... of the five largest extinction events of the Phanerozoic, (Sepkoski, 1996; Hallam and Wignall, 1997; Hallam, 2002), the Triassic– Jurassic boundary has been studied by different authors in different localities all over the world. For example, the stratigraphy of the Triassic-Jurassic boundary in Europe has been well-studied in southern Swe- den and northwest of Poland (Bertelson, 1978), in the Northern Calcareous Alps of Austria (Satterley et al., 1994) and in England (Hallam, 1990, 1995). Pronounced facies changes across the Triassic-Jurassic boundary have been studied in Nevada, USA (Hallam and Wignall, 2000), in southern Tibet (Hallam et al., 2000) and in Hungary (Haas and Tardt- Filacz, 2004). Hallam and Wignall (1999) mentioned that the contact between the Triassic and Jurassic in Africa and Asia is generally poorly known because of a paucity or absence of marine successions across the boundary. The present study presents good evidence for the unconformable relationship between the fluvial and fluvio-marine facies of the uppermost Triassic and lowermost Jurassic on the shelf area in Egypt and Sudan (northeast Africa), Jordan, and Saudi Arabia (southwest Asia) (Fig. 1). However, the recognition of the Triassic-Jurassic boundary in Sudan is difficult because the facies around the boundary are represented by coarse clastics. Well-exposed sections and subsurface data in other studied localities provide a good opportunity to contribute a better un- derstanding about the facies changes, tectonics, and volcanism across the Triassic-Jurassic contact. The Triassic rocks in Egypt were studied in the subsurface in the Western Desert, while the exposed Triassic-Jurassic rocks are measured in Northern Galala (north Eastern Desert) and in western and central Sinai (Fig. 1). On the Arabian Peninsula, the Triassic–Jurassic rocks were examined east of the Dead Sea rift at Jordan and Al Mustawi area (Al Qasim Province), Saudi Arabia (Fig. 1). The aim of this study is to explain the facies architecture across the Triassic-Jurassic boundary in Egypt, Sudan, Jordan and in Saudi Arabia and to clarify the nature of the contact at the Triassic–Jurassic boundary. Also, this study aims to determine the factors responsible for the unconformable contact and major gap between the two ...
Similar publications
Introduction: A prostate cancer case in sub-Saharan Africa is rising. In Sudan, prostate cancer ranks third at after
Market sensing and internal information dissemination are popular concepts in the field of marketing and strategic management. Scholars in these fields are appreciating the roles of market sensing and internal information dissemination in understanding the business environmental changes to sustain competitive advantages for better firm performance....
Citations
... The overlying facies resemble alternating intertidal carbonate flats and siliciclastic littoral deposits that display an aggrading trend. The Triassic-Jurassic boundary in Arabia witnessed a clear discontinuity which reflects a piece of evidence for the sudden lowering in the sea level as resulted of depositing fluvial to continental facies represented by the Upper Triassic Rukhman Formation in northern Saudi Arabia and its equivalent Minjur Sandstone in southern areas (Khalifa 2007). ...
... The Minjur Formation shows thinning north of the type locality (Powers et al. 1966). The boundary between the Minjur Sandstone and Marrat Formation is located at the contact of grey, friable, cross-bedded sandstone of the Minjur Sandstone below and the tan-brown limestone above (Khalifa 2007). ...
Late Triassic plant macro-remains are extremely rare in an equatorial belt stretching across the North of Gondwana from northern South America to Arabia. Located between the Laurussian floral province to the North and the Gondwana floral province to the South, this large area, is almost entirely lacking palaeobotanical data. Thus, this region is of special interest to our knowledge of Late Triassic floral provincialism and plant distribution. Based on impressions from ferruginous crusts, the first record of identifiable plant macro-remains from the Late Triassic (Norian-Rhaetian) Minjur Formation is described, as belonging to the bennettitalean taxon Zamites aff. persicus. This new finding at least tentatively supports palynological data, which indicated similarities between the Late Triassic (Norian) palynoflora of the Minjur Formation of the Arabian Peninsula on the southern shores of the Tethys and the Norian palynoflora of Iran, during this time located in the northern part of the Tethys.
... The Lower Jurassic Mashabba Formation consists of a 19-m-thick alternation of limestone and calcareous sandstone beds and rests unconformably on Triassic deposits at Arif El-Naga, northeast Sinai (El-Azabi and El-Araby, 2005). In southern Sinai, the siliciclastic-dominated Lower Jurassic Raqaba Formation rests unconformably on the Lower to Middle Triassic Qiseib Formation in the foothills of the Tih escarpment (Khalifa, 2007). ...
The Lower Jurassic Mashabba Formation crops out in the core of the doubly plunging Al-Maghara anticline, North Sinai, Egypt. It represents a marine to terrestrial succession deposited within a rift basin associated with the opening of the Neotethys. Despite being one of the best and the only exposed Lower Jurassic strata in Egypt, its sedimentological and sequence stratigraphic framework has not been addressed yet. The formation is subdivided informally into a lower and upper member with different depositional settings and sequence stratigraphic framework. The sedimentary facies of the lower member include shallow-marine, fluvial, tidal flat and incised valley fill deposits. In contrast, the upper member consists of strata with limited lateral extension including fossiliferous lagoonal limestones alternating with burrowed deltaic sandstones. The lower member contains three incomplete sequences (SQ1-SQ3). The depositional framework shows transgressive middle shoreface to offshore transition deposits sharply overlain by forced regressive upper shoreface sandstones (SQ1), lowstand fluvial to transgressive tidal flat and shallow subtidal sandy limestones (SQ2), and lowstand to transgressive incised valley fills and shallow subtidal sandy limestones (SQ3). In contrast, the upper member consists of eight coarsening-up depositional cycles bounded by marine flooding surfaces. The cycles are classified as carbonate-dominated, siliciclastic-dominated, and mixed siliciclastic-carbonate. The strata record rapid changes in accommodation space. The unpredictable facies stacking pattern, the remarkable rapid facies changes, and chaotic stratigraphic architecture suggest an interplay between allogenic and autogenic processes. Particularly syndepositional tectonic pulses and occasional eustatic sea-level changes controlled the rate and trends of accommodation space, the shoreline morphology, the amount and direction of siliciclastic sediment input and rapid switching and abandonment of delta systems.
... The first one, situated at the basal boundary of the Marrat Formation, corresponds to a time gap of approximately 20 Myr having lead to contacts between Triassic and Toarcian deposits. The tectonic control of this unconformity remains poorly understood but could relate to a long period of regional uplift and erosion caused by a tectonic inversion of the Karoo rifting between Madagascar and East Africa (Delvaux, 2001;Baud et al., 2005;Khalifa, 2007;Pöppelreiter et al., 2018) or the early detachment of the Indian Plate from the Africa/Arabia Plate ( Grabowski and Norton, 1995). At the top of the Marrat Formation, the Toarcian−Aalenian hiatus corresponds to a major unconformity at the scale of the Arabian Platform, which marks the beginning of the Middle Jurassic Dhruma Formation. ...
A high-resolution sequence-stratigraphic framework is proposed for the Marrat Formation (Early to Middle Toarcian of Saudi Arabia) by presenting new outcrop and shallow core sedimentological data located along a 280 km long N-S transect south of Riyadh and westward subsurface correlations based on gamma-ray wireline logs (200 km Ar Riyadh to Khurais Field). This extended spatial cover allows the identification of a northward thickening of sedimentary successions due to syndepositional differential subsidence. Basically, these successions formed on low-energy falt-topped platform with limited accommodation space in which mainly retrogradational and aggradational stacking patterns were recorded. Overall, the evolution from continental meandering fluvial deposits at the base of the formation to tidal or wave-dominated siliciclastic and carbonate inner-platform deposits indicate a progressive marine transgression that reached its maximum during the Middle Toarcian bifrons Zone. In details, we identify two 3rd-order sequences that onlap southward on to the Triassic−Jurassic unconformity. Higher-energy siliciclastic shoreline facies were deposited in the upper transgressive systems tract of depositional sequences during periods of high accommodation space. The carbonate units consist of platform mud-dominated facies and are well-developed during the maximum marine transgressions of the two Marrat sequences. Continental red shales and fluvial sandstone deposited in a humid and warm environment during the Toarcian bifrons Zone (sublevisioni Subzone) indicate a higher terrigenous input interrupting the two maximum transgressive sequences. The sequences were likely produced by global sea-level changes but also appear to have been influenced by local climate changes with humid and warm conditions during periods of regression and more arid conditions during transgressions. This study serves as an outcrop analog, provides guidelines for hydrocarbon exploration and improves seismic interpretations. Overall, these new facies analysis, wireline log data, stratigraphic interpretations, and regional correlations contribute to a broader understanding of the Early Jurassic successions of the Arabian Platform.
... By the end Triassic, gentle tectonic activity was registered along the African-Arabian Neotethys margin, creating frequent unconformities due to the emersion of this large domain (Guiraud et al. 2005). In the Arabian Basin, east-west shortening (in the south) and northeast-southwest shortening (in the north) caused intermittent erosion of the Upper Triassic facies (Khalifa 2007). In contrast, subsident regions accumulated large amounts of carbonates and evaporates. ...
Roughly 44% of the world’s total known hydrocarbon resources are located in North Africa and the Middle East, from Algeria in the west to the Zagros region of Iran in the east. This includes more than 200 giant fields in the Middle East. North African basins, mainly in Algeria, Libya, and Egypt, contain 4% of the world’s oil and gas reserves and nearly 40 giants. The most recent giant field resides in the offshore Levantine Basin. In this chapter, the region’s geological history and petroleum systems are reviewed, including descriptions of the regional habitats and stratigraphy of the main reservoirs and source rocks. The Late Pre-Cambrian to Phanerozoic tectonostratigraphy is characterized by six major phases: (1) basement assembly and Infracambrian extension; (2) development of Cambrian to Carboniferous passive margins; (3) Late Carboniferous to Early Permian Hercynian orogeny; (4) post-Hercynian breakup of Gondwana; (5) collision with Eurasia; and (6) Red Sea rifting and the closing of Neotethys. For most of the Phanerozoic, the terranes of North Africa and Arabia were locked together at the northern rim of Gondwana. They shared a similar geodynamic history and generally similar climates. Their plate margins interacted over time with the water masses of three oceans: Proto-, Paleo-, and Neotethys. Throughout the Paleozoic, the region lay on a wide “ramp-like” passive margin facing northward toward Paleotethys. The main sediment source was the large hinterland to the south, with prevailing south to north and southeast to northwest-directed paleocurrents. Multiple marine transgressions across a low-relief continental platform were interrupted by at least four glacial events: Late Ordovician (Hirnantian), Silurian, Carboniferous, and Early Permian. Deposition of siliciclastics predominated throughout the Paleozoic whereas carbonates were much less common. The most important tectonic event was the mid-Carboniferous Hercynian composite-orogeny, which caused major uplift and erosion. The Hercynian represented the final closure of Paleotethys and produced many fault blocks and arches that would later host many of the major hydrocarbon accumulations of North Africa and eastern Arabia. The Mesozoic–Cenozoic sedimentary sequence similarly consists of eustatically and tectonically controlled depositional cycles along the newly formed passive margin of Neotethys. Triassic to mid-Cretaceous facies along North Africa are almost everywhere shallow marine, nearshore, deltaic, and continental. Neotethys reached its maximum extent in the Late Cretaceous at which time carbonate sequences dominated. In addition to the Hercynian Orogeny, two other compressional events had major consequences on North Africa–Arabia petroleum systems. The closing of Neotethys began in the late Santonian (~84 Ma) and the convergence between Eurasia and Africa–Arabia sent pulses of compressional deformation across the plate. This corresponded to the first phase of the complex Alpine orogenic cycle and caused folding, basin inversion, and strike-slip faulting along the African–Arabian Neotethyan margin (the “Syrian Arc”), and thrusting and ophiolite obduction in Oman. Compression was renewed at the end of the Maastrichtian and continued into the early Paleocene, followed by even stronger effects in the Late Eocene. Eruption of the Afar plume at about 31 Ma marked the beginning of a new phase of continental rifting that had dramatic effects on all aspects of the geology of the region. The Gulf of Aden ruptured first in the Early Oligocene, followed by the southern Red Sea in the Late Oligocene. At the Oligocene–Miocene transition, the remainder of the Red Sea north to the Gulf of Suez underwent a regional dike event and accompanying extensional faulting. Initiation of the Gulf of Aqaba—Dead Sea transform plate boundary occurred in the Middle Miocene, completing formation of the independent Arabian plate. The Neotethys Ocean also ceased to exist in the Middle Miocene following a collision between Eurasia and the Arabian plate to form the Bitlis–Zagros suture and fold belt. The Arabian plate was progressively tilted to the northeast as a result of both uplift and rifting of Arabia from Africa, and structural loading of the northeast margin by the Zagros fold belt. Recent tectonic activity is mainly concentrated along the Maghrebian Alpine Belt, the offshore Nile Delta, the Red Sea–East African (or “Afro-Arabian”) Rifts Province, the Aqaba–Dead Sea–Bekaa sinistral strike-slip fault zone, and some major intra-plate fault zones including the Guinean–Nubian, Aswan, and central Sinai lineaments. Our review of the petroleum systems of North Africa and Arabia is brief and includes only highlights of the hydrocarbon occurrences found across this broad and complex region. Based on the age of source rocks, it is possible to distinguish an Infracambrian Petroleum System, Palaeozoic-related Petroleum Systems, and linked Mesozoic–Cenozoic Petroleum Systems. The sedimentary fill contains numerous source rocks, some of them with exceptional quality and regional distribution, such as the Silurian “hot shale”. Producing reservoirs are found in both siliciclastics and carbonates. The proximity and juxtaposition of source rocks with thick reservoirs minimized the need for complex oil migration pathways, but also facilitated hydrocarbon expulsion and migration over long distances. Huge amounts of evaporites and shales are present, providing excellent lateral and ultimate top seals. Hydrocarbons are trapped in literally all stratigraphic units from the fractured Neoproterozoic basement to the youngest Pliocene–Quaternary sediments.
... By the end Triassic, gentle tectonic activity was registered along the African-Arabian Neotethys margin, creating frequent unconformities due to the emersion of this large domain (Guiraud et al. 2005). In the Arabian Basin, east-west shortening (in the south) and northeast-southwest shortening (in the north) caused intermittent erosion of the Upper Triassic facies (Khalifa 2007). In contrast, subsident regions accumulated large amounts of carbonates and evaporates. ...
Roughly 44% of the world's total known hydrocarbon resources are located in North Africa and the Middle East, from Algeria in the west to the Zagros region of Iran in the east. This includes more than 200 giant fields in the Middle East. North African basins, mainly in Algeria, Libya, and Egypt, contain 4% of the world's oil and gas reserves and nearly 40 giants. The most recent giant field resides in the offshore Levantine Basin. In this chapter, the region's geological history and petroleum systems are reviewed, including descriptions of the regional habitats and stratigraphy of the main reservoirs and source rocks. The Late Pre-Cambrian to Phanerozoic tectonostratigraphy is characterized by six major phases: (1) basement assembly and Infracambrian extension; (2) development of Cambrian to Carboniferous passive margins; (3) Late Carboniferous to Early Permian Hercynian orogeny; (4) post-Hercynian breakup of Gondwana; (5) collision with Eurasia; and (6) Red Sea rifting and the closing of Neotethys. For most of the Phanerozoic, the terranes of North Africa and Arabia were locked together at the northern rim of Gondwana. They shared a similar geodynamic history and generally similar climates. Their plate margins interacted over time with the water masses of three oceans: Proto-, Paleo-, and Neotethys. Throughout the Paleozoic, the region lay on a wide "ramp-like" passive margin facing northward toward Paleotethys. The main sediment source was the large hinterland to the south, with prevailing south to north and southeast to northwest-directed paleocurrents. Multiple marine transgressions across a low-relief continental platform were interrupted by at least four glacial events: Late Ordovician (Hirnantian), Silurian, Carboniferous, and Early Permian. Deposition of siliciclastics predominated throughout the Paleozoic whereas car-bonates were much less common. The most important tectonic event was the mid-Carboniferous Hercynian composite-orogeny, which caused major uplift and erosion. The Hercynian represented the final closure of Paleotethys and produced
... By the end Triassic, gentle tectonic activity was registered along the African-Arabian Neotethys margin, creating frequent unconformities due to the emersion of this large domain (Guiraud et al. 2005). In the Arabian Basin, east-west shortening (in the south) and northeast-southwest shortening (in the north) caused intermittent erosion of the Upper Triassic facies (Khalifa 2007). In contrast, subsident regions accumulated large amounts of carbonates and evaporates. ...
... The major sequence boundary SB1 between the Minjur/Marrat formational boundary is coincident with tectonic uplift and non-deposition in the whole of the Arabian/African plates (e.g., Sharland et al., 2001;Khalifa, 2007;Al-Husseini, 2015), where the whole Hettangian to the Pliensbachian cycle boundaries are amalgamated with minor cycle boundary JTo1 (183 Ma) of Haq (2018). ...
... The upper member is mainly composed of limestone. Interbedded are some shale units that increase upward in thickness (Powers et al. 1966;Khalifa 2007). ...
Digital outcrop modeling delivers high resolution and quantitative sedimentological data inaccessible or hard to be acquired from the subsurface data. This study provides outcrop-analogue study for the Upper Triassic Upper Minjur Member and the Lower Jurassic Lower Marrat Member. These important hydrocarbon reservoirs targets in Saudi Arabia. Its architecture is poorly understood and scope of this outcrop analogue project. The study was carried out on two selected outcrop belts of Minjur and Marrat formations west of Riyadh in Central Saudi Arabia. The main objective of the study is to construct a high resolution digital outcrop analog geological model that captures key sedimentological and stratigraphic heterogeneity. The study was based on field description of vertical sections and lateral outcrop scans using terrestrial laser scanning or LiDAR data of the Minjur and the Marrat Formations. The laboratory analysis included sedimentological and petrographic analyses of thin sections as well as processing, analysis and interpretation of raw LiDAR data. Data were combined in a 3D digital model.
The model revealed the spatial distribution of lithofacies and its stacking patterns at the outcrop scale in 2D and 3D. The model also revealed reservoir body dimensions, zonations, continuity, architecture as well as inter-reservoir seals and barriers at outcrop scale. The high resolution information and geological data compiled in this study might help to better understand and prediction reservoir quality and architecture at the inter-well spacing of equivalent reservoirs in the subsurface.
... The major sequence boundary SB1 between the Minjur/Marrat formational boundary is coincident with tectonic uplift and non-deposition in the whole of the Arabian/African plates (e.g., Sharland et al., 2001;Khalifa, 2007;Al-Husseini, 2015), where the whole Hettangian to the Pliensbachian cycle boundaries are amalgamated with minor cycle boundary JTo1 (183 Ma) of Haq (2018). ...
Well-exposed stratigraphic sections of the Toarcian siliciclastic/carbonate deposits of the Marrat Formation
exposed at the Khashm adh Dhibi area (southwest of Riyadh city, Saudi Arabia) were studied for their facies
associations and controls on sequence development. Seven facies associations from tide-dominated deltaic to
inner carbonate ramp were recognized. Inferences based on facies relationships, characteristics of the sequence
boundary and other characteristics suggest deposition of the Marrat Formation during three 3rd order sequences.
These can be further classified into seventeen 4th order shallowing-upward small-cycle sets. Correlation of the
recorded sequences boundaries within the Arabian/African Plates, Europe, and global schemes, reflect a strong
eustatic control during the early Jurassic age with recognizable tectonic signature of the Gondwanland rift
effects that caused a long period of regional uplift and non-deposition across the Triassic/Jurassic and early/
middle Jurassic unconformities.
... The major sequence boundary SB1 between the Minjur/Marrat formational boundary is coincident with tectonic uplift and non-deposition in the whole of the Arabian/African plates (e.g., Sharland et al., 2001;Khalifa, 2007;Al-Husseini, 2015), where the whole Hettangian to the Pliensbachian cycle boundaries are amalgamated with minor cycle boundary JTo1 (183 Ma) of Haq (2018). ...
Well-exposed stratigraphic sections of the Toarcian siliciclastic/carbonate deposits of the Marrat Formation exposed at the Khashm adh Dhibi area (southwest of Riyadh city, Saudi Arabia) were studied for their facies associations and controls on sequence development. Seven facies associations from tide-dominated deltaic to inner carbonate ramp were recognized. Inferences based on facies relationships, characteristics of the sequence boundary and other characteristics suggest deposition of the Marrat Formation during three 3rd order sequences. These can be further classified into seventeen 4th order shallowing-upward small-cycle sets. Correlation of the recorded sequences boundaries within the Arabian/African Plates, Europe, and global schemes, reflect a strong eustatic control during the early Jurassic age with recognizable tectonic signature of the Gondwanland rift effects that caused a long period of regional uplift and non-deposition across the Triassic/Jurassic and early/ middle Jurassic unconformities.
