Petrography, fluid-inclusion microthermometry, stable isotope analyses, and radiometric (206Pb/238U) dating of Upper Triassic dolostones, saddle dolomite, and quartz and calcite cements were used to constrain the timing and conditions of dolomitization and cementation in the context of the tectonic evolution of a basin in the northern United Arab Emirates. Dolomitization (ca. 152.4 Ma) and precipitation of saddle dolomite (ca. 146.8 Ma), calcite (ca. 144.6 Ma), and quartz cements are attributed to focused synrifting flow of hot basinal brines into grain-supported limestones in which permeability was enhanced by incursion of meteoric waters beneath a disconformity surface. Another calcite cement generation (ca. 99.7 Ma) was formed by flow of hot brines during tectonic compression related to the obduction of Oman ophiolites in the Late Cretaceous. Thus, this paper provides new insights into (1) stratigraphic controls on and timing of hydrothermal (hot basinal brines) dolomitization, (2) the origin of closely associated intraformational limestones and dolostones, and (3) linkages between diagenesis and thermochemical modifications of basinal brines during tectonic evolution of sedimentary basins.Hydrothermal dolomitization, which has gained increasing interest during the past three decades, results in massive and/or stratabound dolostones (e.g., Martín-Martín et al., 2015). Despite numerous studies, there are still several uncertainties regarding: (1) burial depths and precise timing of hydrothermal dolomitization, (2) lack of adequate explanation for the sharp boundaries between limestone and dolostone successions, and (3) origin and circulation patterns of the hydrothermal fluids.In this study, petrography (Figs. 1A–1K), C, O, Sr, and Mg isotopes, fluid-inclusion microthermometry (FIM) (Figs. 2A–2C), and radiometric (206Pb/238U) dating (Figs. 3A–3D) of Upper Triassic carbonates of the Ghalilah Formation, northern United Arab Emirates, were used to: (1) explain the parallel bedding and sharp boundary between the stratabound dolostones and the overlying limestone beds, and (2) constrain the origin and timing of fluid flow within the framework of the regional tectono-sedimentary evolution of the basin. The Ghalilah Formation is part of the 1700-m-thick Permian–Triassic carbonate succession that was deposited in a stable platform along the margins of the Neo-Tethys Ocean (Hönig et al., 2017). The Permian and Lower–Middle Triassic limestones are extensively dolomitized. In contrast, the studied Upper Triassic limestones are locally dolomitized. The area was affected by obduction of ophiolites in the Late Cretaceous and thrusting caused by the Zagros orogeny (Oligocene–Miocene; Searle, 1988). The formation, which was deposited in a back-ramp setting with lagoonal to tidal-flat deposits, is subdivided into three members (Fig. 1C; Ellison et al., 2006). The upper part of the Sakhra Member is completely dolomitized (Figs. 1A–1C and 1E). Layers underneath the dolostone intervals, which show little dolomitization, are composed of mixed siliciclastic-carbonates and marl. A significant hiatus occurs at the top of the dolomitized Sakhra Member (Hönig et al., 2017). The underlying, slightly dolomitized, argillaceous Sumra Member comprises mixed fine-grained carbonate-siliciclastics. The overlying undolomitized Shuba Member is composed of bioturbated wackestones and packstones.In total, 112 samples were collected from the dolomite and calcite cements along with host dolostones and examined using optical, cathodoluminescence, and backscattered electron microscopy. Representative samples were microdrilled to obtain carbonates for C, O, Sr, and Mg isotope analyses; for methods, see Geske et al. (2015a) and Mansurbeg et al. (2016). Primary two-phase fluid inclusions were subjected to microthermometry measurements. In situ 206Pb/238U dating of dolostones, saddle dolomite, and calcite was performed using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS), which consisted of a quadrupole ICP-MS (ICapQ-ThermoFisher) coupled with a 193 nm excimer laser-ablation microprobe (Analyte Excite Teledyne-Cetac; Salih et al., 2020; Elisha et al., 2021).The dolostones, dated at ca. 152 ± 21 Ma (Fig. 3A), exhibit extensive local brecciation and cementation by saddle dolomite (SD) and C1 calcite. The brecciation is attributed to forceful fluid flow (Katz et al., 2006). Depositional textures of precursor limestones include grainstones and floatstones/rudstones (Fig. 1C), which contain dissolved bivalves with moldic pores filled with SD (Fig. 1F). The dolostones are composed of rhombic dolomite and SD that replace allochems, syntaxial calcite overgrowths, and equant calcite. Vugs (0.3–10 cm) in the dolostones are aligned parallel to bedding, and, locally, breccia fractures are filled with SD (dated ca. 146 ± 31 Ma; Fig. 3B) followed by blocky calcite cement (C1; dated ca. 144 ± 8 Ma; Figs. 1G and 3C). A few prismatic quartz crystals (1–2 cm) cover the SD (Fig. 1H). The SD exhibits sharp contact with the calcite or shows evidence of partial calcitization (Fig. 1 K). Bedding-parallel fractures and subvertical fractures extending from bedding-parallel stylolites are solely filled with blocky calcite (C2; Figs. 1I and 1J) dated ca. 99 ± 28 Ma (Fig. 3D).The dolostones gave δ13CVPDB of −0.3‰ to +3.1‰, δ18OVPDB of −8.8‰ to −5.6‰, 87Sr/86Sr ratios of 0.708610–0.709835, and δ26MgDSM3 of −1.8‰ to −1.3‰ (Figs. 2A and 2B), where VPDB indicates the Vienna Peedee belemnite reference value, and DSM3 refers to a standard reference material used for magnesium isotope ratios. The lowest δ18O and δ26Mg values are typical for dolostones rich in replacive SD. SD in the vugs and host dolostones gave δ13C of −1.1‰ to +2.2‰, δ18O of −10.8‰ to −6.7‰, 87Sr/86Sr ratios of 0.708320–0.710306, and δ26Mg of −2.3‰ to −2‰. The C1 had δ13C of −1.7‰ to +1.6‰, δ18O of −10.3‰ to −6.5‰, and 87Sr/86Sr of 0.708327–0.709828. The C2 had δ13C of −0.8‰ to +1.2‰, δ18O of −7.9‰ to −4.2‰, and 87Sr/86Sr of 0.709291–0.711048. FIM of vug-filling and breccia fracture-filling cements and host dolostones (Fig. 2C) showed that: (1) rhombic dolomite in the dolostone has homogenization temperature (Th) values of 91–105 °C and salinity values of 18.4–21.9 wt% NaCl eq., (2) SD has Th values of 94–173 °C and salinity values of 17.5–22.9 wt% NaCl eq., (3) C1 calcite has Th values of 139–183 °C and salinity of 14.7–22.4 wt% NaCl eq., and (4) quartz has Th values of 146–185 °C and salinity of 18.3–22.1 wt% NaCl eq. The C2 calcite that fills tension gashes and bedding-parallel fractures has Th values of 96–138 °C and salinity of 15.9–20.3 wt% NaCl eq.Based on the data obtained, a conceptual model was developed to address the timing and controls on dolomitization and cementation by SD, calcite, and quartz (Figs. 4A–4C). Prior to dolomitization, diagenesis of the precursor limestones included precipitation of scalenohedral calcite cement rims around the allochems, presumably from marine pore waters (Fig. 4A; Choquette and James, 1990). This diagenetic event was followed by the incursion of meteoric waters beneath the surface of subaerial exposure (disconformity) developed along the upper part of Sakhra limestones (Fig. 4B). The incursion caused karstification, which further enhanced permeability of the grain-supported limestones, and cementation by equant calcite and syntaxial overgrowths (Fig. 4B). The disconformity was caused by a major fall in sea level (Fig. 1D; Haq and Al-Qahtani, 2005). Hence, early dolomitization can be precluded because it occurred during a marine transgression (Machel, 2004). The 206Pb/238U dating of the dolostones (ca. 152–146 ± 21.3 Ma; Figs. 3A and 3B) suggests that the flux of dolomitizing, hydrothermal (hot basinal brine) fluids was associated with heat flow during the second rifting phase of the Neo-Tethys Ocean, which occurred around 185–170 Ma (Ali et al., 2013, 2017). The upward flow of hydrothermal fluids is envisaged to have occurred along normal faults (Callot et al., 2010) and then into the permeable grain-supported limestones in the upper part of the Sakhra Member underneath the disconformity (Fig. 4C). The flow of hydrothermal fluids is suggested by the high Th (94–173 °C; Fig. 2C), δ18O signatures (−10.8‰ to −6.7‰), and the presence of SD in the dolostones (Zenger, 1983; Breesch et al., 2010). Considering the dates of Triassic dolostones and the average thickness of the overlying Triassic–Jurassic succession (Ellison et al., 2006), it is inferred that dolomitization occurred at depths of around 1700 m. The estimated burial temperature would have been 65–85 °C, assuming a geothermal gradient of 30–40 °C/km, which further corroborates the hydrothermal origin of the dolomites. A plausible explanation for the lack of significant dolomitization in limestones underlying the dolostone intervals of the Sakhra Member and underlying Sumra Member is their low depositional permeability and unfavorable lithology (quartzitic mud/wackestones, hybrid arenites, and marls).Evidence suggesting that the hydrothermal fluids underwent thermochemical evolution subsequent to dolomitization and dolomite cementation includes: (1) a change in mineralization from dolomite to quartz, followed by C1 calcite, and (2) trends of increasing Th with overlapping salinity in the vug-filling SD and blocky calcite (C1) and quartz. The input of 87Sr is attributed to the interaction of the hot basinal brines with felsic lithologies (Mansurbeg et al., 2021). The wide range of Th, which has also been documented by other studies on hydrothermal dolomites (Smith, 2004; Lavoie et al., 2005), is attributed to varying depths and/or degrees of cooling experienced by the dolomitizing brines (Bons et al., 2014).The mostly positive δ13C values of these dolomites suggest derivation of dissolved carbon from the host carbonate rocks. The higher 87Sr/86Sr ratio of C1 and C2 than dolostone and SD indicates the input of radiogenic strontium derived from silicate sources. Mg in the hydrothermal fluids was probably derived from interaction with underlying Permian–Triassic dolostones, whereas high salinity indicates dissolution of the Cambrian Hormuz salt (Hassanpour et al., 2021). The lower δ26Mg of the dolostones and SD (Fig. 2B) than typical values reported for Triassic Seawater (+0.28‰; Hu et al., 2017) supports Mg derivation from the hot dolomitizing brines (Lavoie et al., 2014). Additional potential sources of Mg for the dolomitizing brines include: (1) Triassic marine pore waters, (2) Mg-bearing evaporite deposits of the Cambrian Hormuz salt (–1.09‰ to −0.38‰; Geske et al., 2015a), and (3) Mg-rich clay minerals in basinal mudstones (global average of −0.49‰ to −0.27‰; Wombacher et al., 2009). The lower δ26Mg value than those inferred for hydrothermal dolomites elsewhere (Fig. 2B) is poorly understood. Fluid-mineral interaction can potentially lead to the enrichment of 24Mg and, thus, reduction in δ26Mg values by processes such as selective leaching, isotopic exchange, Mg-mineral precipitation, and equilibrium isotope fractionation (Teng, 2017; Oelkers et al., 2018).The relatively narrow ranges of δ26Mg values observed in both the dolostones and SD (Fig. 2B) imply that these dolomites were formed from the same basinal brines. This interpretation is reinforced by the relatively similar Sr-isotopic values of both dolomite types. Furthermore, the data set obtained indicates that the dolomitizing brines responsible for dolomitization and cementation by SD underwent comparable mineral-water evolution pathways (cf. Mansurbeg et al., 2021). This proposition gains further support from the dominantly marine-derived δ13C values in both the SD and dolostone samples (Fig. 2A). The few negative δ13C values observed in SD could be related to the derivation of 12C from the degradation of organic matter/hydrocarbons (Zhang et al., 2020). The insignificant correlation between the O and Mg isotopes of the dolomites studied and those reported in the literature (Geske et al., 2015b) raises doubts about the extent of temperature control on Mg-isotope fractionation (Azmy et al., 2013) within rock-buffered isotopic systems (Lavoie et al., 2014).The age obtained for C1 (ca. 144 ± 8 Ma), which paragenetically postdates SD, corroborates the focused synrifting flow of hot basinal brines. This implies that the hydrothermal fluids responsible for the formation of dolomite and C1 calcite represent deep basinal brines, i.e., unrelated to heat generated by magmatic processes, which have a limited duration (Karakas et al., 2017). This interpretation provides a viable explanation for persistent (younger than 26 Ma) hydrothermal activity in the basin, which underwent continuous subsidence from the Permian to Late Cretaceous. In contrast, the age obtained for C2 calcite (Fig. 1I; dated ca. 99 ± 28 Ma) aligns well with the flow of hot basinal brines along stylolites during a lateral tectonic compression event (Morad et al., 2018) caused by the obduction of Oman ophiolites, which started at ca. 94 Ma (Ali et al., 2013, 2017). The relatively lower Th and salinity values in C2 are attributed to the mixing of meteoric waters with hot basinal brines during this tectonic uplift event.This integrated field, petrographic, isotopic, and microthermometric study of the Upper Triassic carbonate succession of the Ghalilah Formation, northern United Arab Emirates, provides new and important insights into the close association of bedding-parallel dolostone and limestone successions. Dolomitization was restricted to grain-supported limestone beds, in which permeability was further enhanced by the incursion of meteoric waters beneath a disconformity. Dolomitization and cementation of breccia fractures and vugs by saddle dolomite (ca. 152–146 Ma), quartz, and calcite (ca. 144 Ma) are attributed to the flow of hot (Th = 94–173 °C) basinal brines (17.5–22.9 wt% NaCl eq.) during synrifting. Limited dolomitization in the underlying layers is due to the dominant lithologies, characterized by low-permeability siliciclastics, marl, and mud-supported limestones. Later lateral flow of hot basinal brines along stylolites driven by the obduction of the Oman ophiolites (Late Cretaceous) caused cementation of fracture-filling blocky calcite (ca. 99 Ma). This latter cement shows evidence of deep meteoric water circulation and mixing with the hot basinal brines.We thank the two anonymous reviewers for constructive comments and suggestions and science editor Marc Norman for valuable guidance.

中文翻译：

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盆地演化过程中不整合面控制的热液白云石化和胶结作用：上三叠统碳酸盐岩，阿联酋


利用岩相学、流体包裹体显微测温、稳定同位素分析以及对上三叠统白云岩、鞍状白云岩、石英和方解石胶结物的放射性 (206Pb/238U) 测年来限制构造背景下白云石化和胶结作用的时间和条件。阿拉伯联合酋长国北部盆地的演化。白云石化（约 152.4 Ma）和鞍状白云石（约 146.8 Ma）、方解石（约 144.6 Ma）和石英胶结物的沉淀归因于热盆地盐水集中同裂流进入颗粒支撑的石灰岩，其中渗透性增强流星水侵入不整合面下方。另一种方解石胶结物（约99.7 Ma）是由与晚白垩世阿曼蛇绿岩仰冲有关的构造挤压过程中热盐水的流动形成的。因此，本文提供了以下方面的新见解：(1) 热液（热盆地卤水）白云石化的地层控制和时间；(2) 密切相关的层内石灰岩和白云岩的起源；(3) 成岩作用和盆地热化学改造之间的联系。沉积盆地构造演化过程中的卤水。热液白云石化作用在过去三十年中引起了越来越多的关注，产生了块状和/或层控白云岩（例如，Martín-Martín 等，2015）。尽管进行了大量的研究，但仍然存在一些不确定性：（1）埋藏深度和热液白云石化的精确时间，（2）对石灰岩和白云岩序列之间的清晰界限缺乏充分的解释，以及（3）白云石的起源和循环模式热液。在这项研究中，岩相学（图 1） 上三叠统碳酸盐岩的 C、O、Sr 和 Mg 同位素、流体包裹体显微测温 (FIM)（图 2A-2C）和放射性 (206Pb/238U) 测年（图 3A-3D）阿拉伯联合酋长国北部的加利拉地层被用来：（1）解释层控白云岩和上覆石灰岩层之间的平行层理和清晰边界，以及（2）限制流体流动的起源和时间。盆地区域构造沉积演化. Ghalilah 地层是 1700 米厚的二叠纪-三叠纪碳酸盐岩层系的一部分，该层系沉积在新特提斯洋边缘的稳定平台上（Hönig 等，2017）。二叠纪和中下三叠世石灰岩广泛被白云石化。相比之下，所研究的上三叠世石灰岩局部发生白云石化。该地区受到晚白垩世蛇绿岩仰冲和扎格罗斯造山运动引起的逆冲作用的影响（渐新世-中新世；Searle，1988）。该地层沉积在后坡道环境中，具有泻湖到潮坪沉积物，可细分为三个部分（图 1C；Ellison 等，2006）。 Sakhra 段的上部完全白云石化（图 1A-1C 和 1E）。白云岩层段下方的地层几乎没有白云石化，由混合硅质碎屑碳酸盐和泥灰岩组成。白云石化 Sakhra 段的顶部出现了显着的断层（Hönig 等，2017）。下伏的、轻微白云石化的泥质苏姆拉段包含混合的细粒碳酸盐-硅质碎屑岩。上覆的未白云石化的 Shuba 段由生物扰动的泥灰岩和泥岩组成。总共从白云石和方解石胶结物以及主体白云岩中采集了 112 个样品，并使用光学、阴极发光和背散射电子显微镜进行了检查。对代表性样品进行微钻孔以获得碳酸盐，用于 C、O、Sr 和 Mg 同位素分析；有关方法，请参见 Geske 等人。 (2015a) 和 Mansurberg 等人。 （2016）。对原生两相流体包裹体进行显微测温测量。使用激光烧蚀电感耦合等离子体质谱 (LA-ICP-MS) 对白云石、鞍状白云石和方解石进行原位 206Pb/238U 测年，该质谱由四极杆 ICP-MS (ICapQ-ThermoFisher) 和193 nm 准分子激光烧蚀微探针（Analyte Excite Teledyne-Cetac；Salih 等人，2020 年；Elisha 等人，2021 年）。 152 ± 21 Ma（图3A），表现出广泛的局部角砾化和鞍状白云石（SD）和C1方解石胶结作用。角砾化归因于强大的流体流动（Katz 等，2006）。前体石灰岩的沉积结构包括颗粒岩和浮石/红岩（图1C），其中含有溶解的双壳类，其铸模孔充满SD（图1F）。白云岩由菱形白云石和 SD 组成，取代了合金、结构方解石过度生长和等量方解石。白云岩中的孔洞 (0.3–10 cm) 与层理平行排列，并且局部角砾岩裂缝被 SD（年代约 146 ± 31 Ma；图 3B）填充，然后是块状方解石胶结物（C1；年代约 146 ± 31Ma；图 3B）。 144 ± 8 Ma；图1G和3C)。一些棱柱形石英晶体（1-2 cm）覆盖了 SD（图 1H）。 SD 表现出与方解石的尖锐接触或显示出部分方解石化的证据（图 1 K）。 与层理平行的裂缝和从与层理平行的缝线延伸的近垂直裂缝仅被块状方解石充填（C2；图1I和1J），其年代可追溯至约1970年。 99 ± 28 Ma（图3D）。白云岩的δ13CVPDB为-0.3‰至+3.1‰，δ18OVPDB为-8.8‰至-5.6‰，87Sr/86Sr比值为0.708610-0.709835，δ26MgDSM3为-1.8‰至- 1.3‰（图2A和2B），其中VPDB表示Vienna Peedee箭石参考值，DSM3指用于镁同位素比的标准参考物质。最低的 δ18O 和 δ26Mg 值是富含替代 SD 的白云岩的典型值。孔洞和宿主白云岩中的 SD 给出的 δ13C 为 -1.1‰ 至 +2.2‰，δ18O 为 -10.8‰ 至 -6.7‰，87Sr/86Sr 比率为 0.708320–0.710306，δ26Mg 为 -2.3‰ 至 -2‰。 C1的δ13C为-1.7‰至+1.6‰，δ18O为-10.3‰至-6.5‰，87Sr/86Sr为0.708327-0.709828。 C2的δ13C为-0.8‰至+1.2‰，δ18O为-7.9‰至-4.2‰，87Sr/86Sr为0.709291-0.711048。孔洞充填和角砾缝充填胶结物与宿主白云岩的 FIM（图 2C）表明：（1）白云岩中​​菱形白云岩的均一温度（Th）值为 91~105 ℃，盐度值为 18.4~21.9 wt% NaCl eq.，(2) SD 的 Th 值为 94–173 °C，盐度值为 17.5–22.9 wt% NaCl eq.，(3) C1 方解石的 Th 值为 139–183 °C，盐度为 14.7 –22.4 wt% 氯化钠当量，(4) 石英的 Th 值为 146–185 °C，盐度为 18.3–22.1 wt% 氯化钠当量。填充张力裂缝和层理平行裂缝的 C2 方解石的 Th 值为 96–138 °C，盐度为 15.9–20.3 wt% NaCl eq。根据获得的数据，开发了一个概念模型来解决时间和控制问题SD、方解石和石英的白云石化和胶结作用（图 4A-4C）。 在白云石化之前，前体石灰岩的成岩作用包括在合金周围偏三角方解石胶结物边缘的沉淀，可能来自海洋孔隙水（图 4A；Choquette 和 James，1990）。这一成岩事件之后，大气水侵入沿 Sakhra 石灰岩上部形成的地面暴露（不整合面）表面下方（图 4B）。侵入引起了岩溶作用，进一步增强了颗粒支撑石灰岩的渗透性，并通过等方解石和构造过度生长而胶结（图4B）。不整合面是由海平面大幅下降造成的（图 1D；Haq 和 Al-Qahtani，2005 年）。因此，可以排除早期白云石化，因为它发生在海侵期间（Machel，2004）。白云岩的 206Pb/238U 测年（约 152–146 ± 21.3 Ma；图 3A 和 3B）表明，白云石化热液（热盆地盐水）流体的通量与热流在第二裂谷阶段有关。新特提斯洋，发生于185~170Ma左右(Ali等，2013，2017)。预计热液向上流动是沿着正断层发生的（Callot 等，2010），然后进入不整合面下方 Sakhra 段上部的可渗透颗粒支撑石灰岩中（图 4C）。高 Th（94–173 °C；图 2C）、δ18O 特征（-10.8‰ 至 -6.7‰）以及白云岩中 SD 的存在表明热液流体的流动（Zenger，1983；Breesch 等）等，2010）。考虑到三叠纪白云岩的年代和上覆三叠纪-侏罗纪序列的平均厚度(Ellison et al., 2006)，推测白云石化作用发生在1700米左右的深度。 假设地温梯度为 30-40 °C/km，估计埋藏温度为 65-85 °C，这进一步证实了白云岩的热液起源。 Sakhra 段和 Sumra 段白云岩层段下方的石灰岩中缺乏显着的白云石化作用的一个合理解释是它们的沉积渗透率低和不利的岩性（石英泥/砂岩、混合砂岩和泥灰岩）。有证据表明热液流体白云石化和白云石胶结作用之后经历的热化学演化包括：（1）矿化从白云石到石英的变化，然后是 C1 方解石，（2）在充填孔洞的 SD 和块状方解石（C1）中 Th 随盐度重叠而增加的趋势）和石英。 87Sr 的输入归因于热盆地卤水与长英质岩性的相互作用（Mansurbeg 等，2021）。其他关于热液白云石的研究也记录了 Th 的广泛范围（Smith，2004 年；Lavoie 等人，2005 年），这归因于白云石化盐水所经历的不同深度和/或冷却程度（Bons 等人） ., 2014)。这些白云岩的 δ13C 值大多为正值，表明溶解的碳源自宿主碳酸盐岩。 C1和C2的87Sr/86Sr比值高于白云石和SD，表明来自硅酸盐源的放射性锶的输入。热液中的镁可能源自与底层二叠纪-三叠纪白云岩的相互作用，而高盐度表明寒武纪霍尔木兹盐的溶解（Hassanpour等人，2021）。白云岩的 δ26Mg 和 SD（图 2B）低于三叠纪海水报告的典型值（+0.28‰；Hu 等人。，2017）支持从热白云石化盐水中提取镁（Lavoie 等，2014）。白云石化卤水的其他潜在镁来源包括：(1) 三叠纪海洋孔隙水，(2) 寒武纪霍尔木兹盐的含镁蒸发岩矿床（–1.09 ‰ 至 -0.38 ‰；Geske 等，2015a），以及(3) 盆地泥岩中富含镁的粘土矿物（全球平均值为-0.49‰至-0.27‰；Wombacher等，2009）。 δ26Mg 值低于推断的其他地方热液白云岩的值（图 2B），但人们对此知之甚少。流体-矿物相互作用可能导致 24Mg 富集，从而通过选择性浸出、同位素交换、镁矿物沉淀和平衡同位素分馏等过程降低 δ26Mg 值（Teng，2017；Oelkers 等，2018） ）。在白云岩和 SD 中观察到的 δ26Mg 值范围相对较窄（图 2B），这意味着这些白云岩是由相同的盆地卤水形成的。两种白云石类型相对相似的 Sr 同位素值强化了这种解释。此外，获得的数据集表明，负责白云石化和 SD 胶结作用的白云石化卤水经历了类似的矿泉水演化路径（参见 Mansurbeg 等人，2021）。这一主张得到了 SD 和白云岩样本中主要来自海洋的 δ13C 值的进一步支持（图 2A）。 SD 中观察到的少数负 δ13C 值可能与有机物/碳氢化合物降解产生 12C 有关（Zhang 等，2020）。研究的白云岩的 O 和 Mg 同位素与文献中报道的（Geske 等人，2015b）之间的相关性不显着，这引起了人们对 Mg 同位素分馏的温度控制程度的怀疑（Azmy 等人，2015b）。，2013）在岩石缓冲同位素系统内（Lavoie等，2014）。获得的C1年龄（约144 ± 8 Ma），其共生晚于SD，证实了热盆地盐水的集中同裂流流。这意味着形成白云石和 C1 方解石的热液流体代表深盆地卤水，即与岩浆过程产生的热量无关，岩浆过程的持续时间有限（Karakas 等，2017）。这一解释为盆地持续（小于26 Ma）热液活动提供了可行的解释，该盆地从二叠纪到晚白垩世经历了持续沉降。相比之下，获得的 C2 方解石年龄（图 1I；年代约为 99 ± 28 Ma）与侧向构造挤压事件期间盆地热盐水沿缝合线的流动非常吻合（Morad 等，2018），该事件是由阿曼蛇绿岩的逆冲，大约开始于。 94 Ma（阿里等人，2013，2017）。 C2 中相对较低的 Th 和盐度值归因于这次构造隆起事件期间大气水与热盆地卤水的混合。这项综合野外、岩石学、同位素和微测温研究对北部 Ghalilah 组的上三叠统碳酸盐岩层序进行了研究。阿拉伯联合酋长国提供了有关平行层理白云岩和石灰岩层序密切联系的新的重要见解。白云石化仅限于颗粒支撑的石灰岩层，其中的渗透性因不整合面下方的大气水的侵入而进一步增强。鞍状白云石（约 152–146 Ma）、石英和方解石（约 144 Ma）对角砾裂缝和孔洞的白云石化和胶结归因于热（Th = 94–173 °C）盆地卤水（17.5 –22.9 wt% 氯化钠当量）在合成裂谷期间。下层白云石化有限是由于主要岩性所致，其特征是低渗透性硅质碎屑、泥灰岩和泥灰岩。后来，受阿曼蛇绿岩（白垩纪晚期）仰冲驱动，盆地热卤水沿着缝合线侧向流动，导致充填裂缝的块状方解石（约 99 Ma）发生胶结。后一种水泥显示了深层大气水循环和与热盆地盐水混合的证据。我们感谢两位匿名审稿人的建设性意见和建议，以及科学编辑马克·诺曼的宝贵指导。