The basement suits of the ANS in the NED mainly consisted of 1) metamorphic rocks belonging to the EAO island arc phase which stretched between 820 and 750 Ma (Kröner et al., 1994; Mansour et al., 2022a). This suite was represented in the area of study by metabasaltic andesite with a schistosity texture that was intruded by latterly developed granitic suites (El-Wakel et al., 2021). 2) The synorogenic suite which developed during a compressional setting that was dominant in the time span between ca. 750 and 610 Ma. (Stern and Hedge, 1985; Mansour et al., 2022a). It is represented in mainly the northern G. Umm Murakhat by dioritic and granodioritic rocks (Figure 2) that are frequently cut by chemically bimodal dykes. 3) The Late Precambrian Hammamat molasse sediments (ca. 590 Ma; Willis et al., 1988) that are intruded, in the area of study, by post-orogenic granitoids. This suite is restricted in the G. Loman region to the northern and northeastern parts of the area of study (Figure 2). 4) Post-orogenic suites of granitoids and dyke swarms that developed during the ANS extensional collapse stage between ca. 610 Ma and 550 Ma (Stern and Hedge, 1985; Platt and England, 1993; Mansour et al., 2022a; Mansour et al., 2023a). This suite is represented mainly in the area of study by monzogranitic and syenogranitic rocks that are traversed by dykes and quartz veins and are contaminated by sub-rounded xenoliths of the older suites (El-Wakel et al., 2021).

Structurally, El-Wakel et al. (2021) reported three phases of deformation in the studied area; two of them are compressional with maximum compressional axis trending N81°W and N13°W. The third phase of deformation was extensional with an N-S trending maximum tension force (Figure 2).

The integration of the sedimentological succession of NED which documents the depositional environments’ major changes and rock exhumation periods (Figure 3) with our thermochronological data will enable documenting the correlation between the cooling and exhumation events.

The lithostratigraphic sequence in the Gulf of Suez and northern Red Sea region ranges from the Cambrian to present times (Figure 3) and can be classified into.

A) The Palaeozoic succession (Figure 3), which was originally divided into three mappable units (Barron, 1907; Hassan, 1967; Said, 1971). A1) The Qebliat Group (Cambrian age, ∼130 m thick) formed from cycles of fluvial to near-shore marine sediments (Hassan, 1967; Said, 1971; Bosworth et al., 2005). A2) The Um Bogma Formation (Carboniferous age, ∼225 m thick) comprises dolomite, sandy marl, and intercalations of silt and sandstone (Kora, 1984; McClay et al., 1998). A3) The Abu Thora Formation (Carboniferous age, ∼214 m thick) comprises varicolored interbedded fluvial sandstone with nearshore marine sandstone, siltstone, shale, and locally thin coal seams. The upper part of the Abu Thora Formation contains basalt sills at several localities (Weissbrod, 1969; Kora, 1984). By the end of the Carboniferous, the Gulf of Suez region was uplifted as indicated by a lack of any Permian marine sediments (Klitzsch and Wycisk, 1987; Klitzsch, 1990).

A debate concerning additional thermal print and plume effect during the northern Red Sed development still exists. The effects and magnitude of different regional tectonic events on the ANS involve the NED terrain (Steckler, 1985; Omar et al., 1989; Omar and Steckler, 1995; Feinstein et al., 1996; Bosworth et al., 2015; Mansour, 2016; Morag et al., 2019). Reconstructing the thermal-tectonic history of the rift flank is capable of providing new insights into these debates, especially with the obvious variation in the topographic growth across the RSRS (Figure 1B). The implication of different low-temperature multi-thermochronometer techniques has proven to be an effective thermal-tectonic history reconstruction tool in different geologic settings (Morag et al., 2019; Boone et al., 2021; Mansour et al., 2022b).

Previously conducted thermochronologic research on the northern segment of the ANS report a prolonged history of cooling with irregular exhumations through fault-bound blocks (Kohn and Eyal, 1981; Omar et al., 1987; 1989; Kohn et al., 1997; Vermeesch et al., 2009; Feinstein et al., 2013; Mansour, 2016; Mansour et al., 2021; Mansour et al., 2023b). The Suez rift flanks provided ZFT cooling age ranges between 674 ± 77 Ma and 381 ± 26 Ma (Mansour, 2016; Mansour et al., 2023b), AFT cooling age ranges between 485 ± 18 Ma and 11 ± 2 Ma (Kohn and Eyal, 1981; Omar et al., 1989; Kohn et al., 1997; Morag et al., 2019; Mansour et al., 2021; Mansour et al., 2023b), and dated AHe samples from 125 ± 5 Ma to 20 ± 2 Ma (Morag et al., 2019). The Aqaba rift flanks yielded AFT cooling age ranges from 266 ± 14 Ma and 11 ± 1 Ma (Kohn and Eyal, 1981; Feinstein et al., 2013). In the vicinity of the region of Eilat, the reported ⁴⁰Ar/³⁹Ar samples show ages of ca. 536 Ma (Vermeesch et al., 2009), ZFT age ranges from 372 ± 27 Ma to 292 ± 22 Ma (Kohn et al., 1992; Vermeesch et al., 2009), and dated AHe samples from 458 Ma to 205 Ma (Kohn et al., 2019). AFT detrital-dated samples vary between 329 ± 37 Ma and 258 ± 18 Ma and AHe cooling ages between 206 Ma and 12 Ma (Vermeesch et al., 2009; Kohn et al., 2019). The Western flank of the Red Sea at the NED yielded SFT (FT in sphene) cooling age ranges from 411 to 338 Ma (Bojar et al., 2002), cooling ages of ZFT range from 367 to 314 Ma (Bojar et al., 2002), and cooling ages of AFT range between 190 ± 8 Ma and 29 ± 2 Ma (Omar et al., 1987).

The ZFT-analyzed mounts satisfy the Chi-square (χ²) test of age homogeneity (Table 1). The concentrations of uranium vary from ca. 393 to 275 μg/g (Table 1). The resulting weighted mean ZFT thermochronological ages and the related standard errors are 322 ± 18 Ma and 319 ± 16 Ma (Figure 2), representing a typical cooling/exhumation through/within the zone of partial annealing (PAZ) of ZFT (240°C–200 °C; Bernet et al., 2009) ca. 321 ± 17 Myrs ago (Table 1).

Obtained AFT cooling ages vary from 115 ± 6 Ma to 33 ± 5 Ma. The resulting cooling ages are detached spatially and temporally (Figure 2; Table 2); the oldest aged AFT sample GUM-10 has a Cretaceous age of 115 ± 6 Ma, indicating a typical cooling/exhumation through/within the PAZ of the AFT technique (110°C–60 °C; Gleadow et al., 1986; Donelick et al., 2005). The AFT age group with younger ages involves the closest four samples closer to the Red Sea, which comprises Eocene-Oligocene ages between 36 ± 5 Ma and 33 ± 5 Ma (Figure 2), indicating a typical cooling/exhumation through/within the PAZ of the AFT technique at ca. 35 ± 5 Ma (Figure 2; Table 2).

The HCTLs that were corrected to the c-axis (Lc) yielded length ranges from 13.4 ± 1.3 μm to 12.5 ± 1.5 μm (Table 3). We measured 487 Dpars as a total, producing value ranges between 1.6 ± 0.5 μm and 1.4 ± 0.5 μm (Table 3). A systematical relationship between the apatite FT ages and the Dpar values is absent (Figure 4).

The thermal history of the area of study was reassembled using the computer software modeling HeFTy v1.8.3 (Ketcham, 2009; Ketcham et al., 2009). The used Monte Carlo algorithm required t-T constraints that were defined by the user. The introduced constraint boxes were constructed according to the resulting ZFT and AFT cooling ages and geological events whose ages are well-known; these events are the post-accumulation event of erosion (PAEE) that was responsible for the removal of the whole ANS by the Cambrian time and the Red Sea initiation during the Oligo-Miocene time (Figure 5). The constraint extensions on both the X and Y-axis were constructed according to the uncertainty in the timing of every one of them. Other constraints (age-based) were constructed according to the obtained cooling ages; else, they were widely constrained, providing more liberty for the t-T paths. The accuracy of the produced t-T paths mainly counts on the number of the used HCTLs. Thus, we have only modeled samples with adequate HCTLs (Table 3).

The produced thermal history paths suggest two possible cooling/exhumation histories for the region of study: 1) the first is sample GUM-10 (Figure 5): affected by a Precambrian fast-cooling event which caused the sample to exhume to near the Earth’s surface. Shortly after, the sample was affected by a slow reheating event that prolonged to the Devonian when another fast-cooling event initiated and exhumed the rock column to the AFT PAZ upper portion. Afterward, the rock column experienced a period characterized by slow cooling till the Eocene when a third cooling event caused it to be uplifted to its recent elevation (Figure 5). 2) The second is sample GUM-01 (Figure 5): affected by a Precambrian fast-cooling event to uplift the rock column to near the Earth’s surface. Then, the rock column was affected by a slow reheating event that might have prolonged till the Cretaceous time when the sample experienced another fast-cooling event during the Jurassic-Cretaceous time, causing its exhumation to reach AFT PAZ. Afterward, the rock column was affected by a third cooling event during the Eocene to be uplifted to the recent altitudes (Figure 5). However, the sample GUM-01 model shows a wide range of cooling/exhumation possibilities extending from the Devonian to the Cretaceous.

From the modeled samples (Figure 5) and the obtained pre-rift AFT cooling ages, no synchronous thermal anomaly to the northern Red Sea rifting (Oligocene-Miocene) was recorded on the t-T models; alternatively, the area of study was exhumed from ca. 60°C equivalent depths (Figure 5).

The analyzed mounts have passed Chi-square (χ²) homogeneity test, indicating the absence of any evidence of multiple age populations (Table 1).

The yielded ages (average 321 ± 17 Ma; Figure 2) are concordant with published ZHe and ZFT thermochronological ages from different localities of the ANS. These reported Carboniferous thermochronological ages have introduced activated uplifts in response to the Devonian-Carboniferous tectonic activities (Kohn et al., 1992; Bojar et al., 2002; Vermeesch et al., 2009; Mansour, 2016). This regional uplift is concordant with changes in the regime of the deposition from the Um Bogma Formation (the Lower Carboniferous, marine affinity) to the Abu Thora Formation (the Upper Carboniferous, erosional nonmarine affinity) (Figure 3).

The obtained AFT cooling ages range from ca. 115 ± 6 Ma to ca. 33 ± 5 Ma. These ages are separated into two geographically differentiated regions, demonstrating a differential response to the different thermal-tectonic events (Figure 2). The geographic differentiation is constant with differential uplifts that were controlled by block movements through boundary faults that characterize the ANS different regions (Kohn and Eyal, 1981; Omar et al., 1987; Omar et al., 1989; Kohn et al., 1997; Vermeesch et al., 2009; Mansour, 2016). Furthermore, the AFT cooling age of the older mount (Cretaceous; GUM-10) is consistent with the stratigraphic sequence showing a change in the deposition environment from the formation of Wata (marine affinity) to the formation of Matulla (nonmarine affinity) (Figure 3), which suggests synchronized exhumations. In contrast, AFT younger-aged groups (Eocene-Oligocene; GUM-01, GUM-03, GUM-05, and GUM-08) are concurrent with previously reported AFT ages in the northern segment of the ANS (Omar et al., 1989; Morag et al., 2019) and the Eocene-Oligocene unconformity and changes in the deposition environment from the Mokattam Formation (marine affinity) to the Tayiba Formation (nonmarine clastics) (Figure 3).

The obtained cooling ages were considered a little older than the producing equivalent rock uplifting activities; this is indicated by a prolonged resident time in AFT PAZ (Figure 4). This conclusion was additionally maintained through the younger-aged AFT sample has 33 ± 5 Ma age, which predates the Red Sea initiation. Consequently, the region has not experienced any higher temperatures than the AFT closure temperature (110 °C) since the Eocene-Oligocene boundary. Furthermore, uplifting from AFT PAZ is supported by thermal history modeling and histograms of the track lengths distribution as the majority of the Lc distributions yield a negative skewness (Figure 4).

The t-T modeling represents different rapid cooling events; these could be represented as rock uplifts if associated with the obtained cooling ages, the well-known geologic events, and the sedimentological succession. These cooling/uplifting events are 1) The Precambrian uplifting event (Figure 4). This is initiated in response to the PAEE and sedimentation of the fluvio-marine Cambrian deposits. 2) Devonian-Carboniferous time uplifting/cooling activity (Figure 4). This is emphasized by our ZFT ages. During this event, the terrain uplifting in the RSRS region was a reaction to the tectonic activity of the Hercynian that caused a change in the sedimentological nature from the Early Carboniferous time Um Bogma marine sediments to the Late Carboniferous time Abu Thora erosional sediments (Figure 3). This uplift caused rock erosion of more than 2.5 km of an Early Palaeozoic succession plus part of the underlying ANS rocks (Kohn et al., 1992; Moustafa and Yousif, 1993). 3) The Cretaceous uplifting activity (Figure 4). This happened when the studied region responded to the Gondwana breakup by differential exhumations. This event caused localized uplifts in northern Africa and the northern Red Sea region (Shalaby and Shawky, 2014; Shalaby, 2017). Additionally, it produced conglomeratic sandstone erosional deposits dominance and multiple hiatus throughout the whole Cretaceous (Figure 3). The effect of this event is previously reported as tectonically-caused structure (strike-slip faults) and major cooling events (Bojar et al., 2002; Feinstein et al., 2013). This regional differential exhumation nature of the ANS is a reaction to the tectonic activities of the Hercynian and the disintegration of the Gondwana which is widely reported in earlier thermochronologic studies (Kohn and Eyal, 1981; Omar et al., 1987; Omar et al., 1989; Kohn et al., 1992; Vermeesch et al., 2009; Feinstein et al., 2013; Mansour et al., 2023b). This differential uplifting nature was probably governed by the activation of faults according to the different directions of the stress field for each of them. 4) Oligo-Miocene uplifting event (Figure 4). This is seemingly concordant with the Red Sea rifting (e.g., Bosworth and Taviani, 1996; Bosworth and Mc Clay, 2001). The produced thermal history modeling (Figure 4) and older rifting AFT cooling ages (Table 2) indicate the absence of any thermal overprint synchronous to the northern Red Sea opening, and the rift shoulders uplifted only from depths comparable to ca. 60 °C (Figure 4).

The exhumation of buried rocks in rift basins is independent of their cooling events, which are determined by thermochronological data; however, it can be predicted if these cooling events are coupled with the reported geologic events and stratigraphic sequence. The exhumation amount that accompanied each of the reported tectonic events could be calculated from the obtained thermochronologic ages and the corresponding PAZ. The paleo-geothermal gradient is not known; therefore, we used a variety of possible geothermal gradients from the recent (25°C/km) to the expected during active tectonism (50°C/km). Afterward, the resulting rates were correlated to the stratigraphic sequence and compared to the synchronic tectonic events. This approach supports obtained cooling ages/events representative for major rock uplifting events: 1) PAEE event. It caused erosion of the entire ANS to transform it into a peneplain surface (Kolodner et al., 2006); consequently, the recent rock exposures isostatically exhumed from their depths of emplacement to near the Earth’s surface. 2) The Hercynian (Variscan) tectonic activity. This influenced the Egyptian ANS partially through differential exhumations and resulted in the complete removal of the Early Palaeozoic succession and a portion of the basement rocks (Stampfli et al., 2002). This event affected the studied region by rock uplift from depths equivalent to the ZFT PAZ temperatures (240°C–200 °C) to ca. 60 °C equivalent depth. This amount of exhumation corresponds to ca. 4 km 3) The Gondwana disintegration activity. This produced convergence between the African and the Eurasian plates, which caused a total rock exhumation of ca. 2.4 km in NED and Sinai (Moustafa and Fouda, 2014). This local influence on the studied region is indicated by the modeling of the t-T history (Figure 5). It is suggested that the effect of the Gondwana breakup event is combined with the Hercynian event to uplift the ANS in the area of study from depths equivalent to ZFT PAZ (240°C–200 °C) to depths equivalent to ca. 60 °C. (4)The northern Red Sea opening. This resulted in rift shoulders exhumation at Wadi Miar with ca. 2.4 km, southern Sinai (Morag et al., 2019). However, in the current area of study, the northern Red Sea development resulted in a rock uplift of ca. 1.2 ± 0.4 km.

The Gulf of Suez is recognized as a non-volcanic rift except for localized simultaneous basaltic subsurface eruptions and surface dikes despite southern Sinai having an anomalously 2.5 km elevated rift flank. Recently, normal faults associated with 23 Ma subsurface basaltic flood of a relatively constant thickness are being reported in the Cairo-Suez region (Bosworth et al., 2015). They are compositionally similar to the Afar flood basalt in the East African Rift which shows a similar magmatic source to the rifting processes and the absence of pre-rift high topography. The pre-rift low topography is documented by the modest erosional-constituting sedimentary formations (300–500 m) in the rift valley (Garfunkel, 1988) and supports no plume-caused doming which would have produced elevated topography and enflamed amounts of erosional preservations. Additionally, Bosworth et al. (2015) delivered 3D seismic interpretations for circular depressions in the Suez rift grabens which were formed through magma evacuation from below. While a syn-rift deep-seated thermal anomaly would last for more than 60 Myr (Ebinger and Sleep, 1998; Bosworth et al., 2015), this is not the case here, suggesting a more localized and limited source of magmatism. Melts lateral migration from the preexisting Afar plume could provide a more localized source (Ebinger and Sleep, 1998; Bosworth et al., 2015). From southern Sinai, Steckler. (1995) suggested lateral heat transfer from Sinai Triple Junction as a source for the exceptional elevations, while Morag et al. (2019) reported concurrent exhumation, rift initiation, and magmatism, which was interpreted as an indicator of mantle plume involvement. Additionally, the Afar plume northward extension toward the margin of the Arabian plate has been reported (Hansen et al., 2012).

The obtained thermochronologic data yields no AFT age resetting, and the distribution of HCTLs supports uplift from the AFT PAZ (110°C–60 °C), while the t-T models restrict this temperature to ca. 60 °C (Figure 5). The recent geothermal gradient is 25 °C (Morgan et al., 1985; Feinstein et al., 1996), and its doubling is expected during the rifting active period (Omar et al., 1989; Kohn et al., 1992), which suggests rift flank uplift at the studied area from depths of ca. 1.2 ± 0.4 km. These elevations are consistent with the current RSRS western flank low topography (Figure 1B), with the highest peak of ca. 1,018 m at Gabal Loman. Considering the facts that the RSRS and Afar basaltic eruptions are compositionally similar, the Suez rift flanks uplifted only through its southern half (Figure 1A); the anomalously high flank is restricted to the southern part of the eastern flank at southern Sinai (Figure 1B), reducing the eastern rift flank uplift from the south (2.4 km; Morag et al., 2019) to the north (1.2 ± 0.4 km; Mansour, 2016) (Figure 1B; cross sections AA’ and BB’); the western flank low topography accompanied the exhumation (1.2 ± 0.4 km; this study) and the vast amount of the Cenozoic volcanism on the Arabian Shield. We proposed a mechanical rift type for the RSRS additional east-southward thermal overprint caused by lateral migration of melts from the Arabian marginal plume as a source for the exceptional southward elevations of the eastern rift flank and the synchronous basaltic eruptions.

The age of the basaltic volcanism associated with the Suez Rift initiation (23 Ma) overlaps with the ages of the rift-related dikes in the Egyptian Eastern Desert, the Sinai, and western Arabia (Bosworth and Stockli, 2016; Nuriel et al., 2017). This suggests a single and rapid rifting pulse as the Red Sea spread northward through the Suez rift until the Dead Sea Transform (DST) fault activated and migrated the stress field. The DST activation (20–18 Ma; Nuriel et al., 2017) caused the Suez rift flanks exhumation deceleration (25–18 Ma; Morag et al., 2019), while it continued along the Red Sea flanks (15 Ma; Szymanski et al., 2016).