Understanding the causes of the formation of hardgrounds provides insights on the oceanographic evolution of a basin. Phosphate-rich hardground formation interrupted carbonate ramp deposition in the Mediterranean during the Miocene. We analyzed the εNd record of three central Mediterranean hardgrounds to identify the origin of the phosphate-rich waters that formed them within the frame of Mediterranean Miocene paleoceanographic evolution. The Nd isotopes suggest that eastern Mediterranean deep waters were controlled by runoff, in contrast to Atlantic and Indian Ocean waters. This Nd isotope record attests to the weakening of Mediterranean circulation during the Miocene due to closure of the Indian Gateway. Limited exchange with Atlantic shallow seawater led to long residence times for deep waters in the basin. This record indicates the role of upwelling in formation of phosphate hardgrounds and shows the influence of global climate change and local paleoceanographic conditions.Phosphate-rich hardgrounds frequently occur in Miocene Mediterranean carbonate successions and are commonly associated with drowning platforms and depositional hiatuses (Föllmi et al., 2008, 2015; Brandano et al., 2020). The interpretations of the causes of their formation, related overall to increased phosphorus (P) burial rates, span from circulation changes linked to deepening of the substrate, global climate evolution and upwelling, to increased humidity and “washhouse” events (Föllmi, 1996; Mutti and Bernoulli, 2003; Böhme et al., 2008; Filippelli, 2008; Föllmi et al., 2008, 2015). Increased P availability in surface waters coincides with enhanced primary productivity and carbon cycle perturbations testified by positive δ13C isotope shifts in carbonate successions. Enhanced P availability is recorded (1) at the Oligocene-Miocene transition, when a glacial maximum led to increased weathering rates (Zachos et al., 2001); (2) during the Monterey event, when global warming at the Middle Miocene Climatic Optimum (MMCO) favored biogeochemical weathering (John et al., 2003; Brandano et al., 2017); and (3) in the Tortonian, when the Carbon Maximum 7 (CM7) perturbation was linked to enhanced oceanic circulation rates (Brandano et al., 2016a, 2020). The geodynamic evolution of the Mediterranean area affected its circulations patterns, making this basin sensitive to climate changes and lapped by upwelling of phosphate-rich deep waters, which controlled the development of hardgrounds. The identification of the water masses that formed these hardgrounds is crucial for reconstructing the paleoceanographic evolution of the basin, i.e., the change through time of the main currents influencing the primary productivity in the Mediterranean. However, published literature has overlooked the problem of the origin of these water masses, focusing mostly on the link between hardground formation and the global P cycle and the role of nutrients on carbonate platform evolution (e.g., Föllmi et al., 2008; Brandano et al. 2016a). Neodymium (Nd) isotopes are a reliable proxy of paleoceanographic changes (Scher and Martin, 2008). However, published Nd isotope records are based mostly on planktonic foraminifera, which do not record the deep-waters fingerprint but rather provide a mixed signal derived from surface, bottom, and pore waters (Pomiès et al., 2002; Kocsis et al., 2008; Cornacchia et al., 2018). We focus on 143Nd/144Nd in shark teeth from hardgrounds, a proxy for deep-water masses. As a rare earth element, Nd is incorporated into apatite at or near the sediment-water interface, making 143Nd/144Nd in shark teeth a proxy for seawater chemistry (Scher and Martin, 2008). This principle makes Nd isotopes the best proxy for targeting the provenance of the deep waters. For this study, shark teeth were chosen because apatite is rich in Nd, is resistant to diagenetic alteration, and is a reliable proxy for seawater chemistry (Kocsis et al., 2009). Thus, this work aims to reconstruct the provenance of deep-water masses that formed hardgrounds within three Miocene carbonate successions of the central Mediterranean, identifying the control of geodynamics on paleoceanography and carbonate platform drownings.The Apennines (Italy) consist mainly of Meso-Cenozoic limestones, relicts of an archipelago of carbonate platforms separated by deep basins (Bernoulli, 2001). The investigated phosphatic hardgrounds mark different Miocene drowning events of the Apulian and the Latium-Abruzzi platforms (Fig. 1).The first sampled hardground crops out in the Fonte del Papa quarry on Maiella Mountain (Apulian platform, Central Apennines) and is late Burdigalian in age (ca. 16 Ma; Brandano et al., 2016b; Fig. 1). The second hardground crops out on the Salento Peninsula near the Porto Badisco locality (Apulian platform, southern Italy) and is late Serravallian in age (ca. 12 Ma; Föllmi et al., 2015; Fig. 1). Lastly, the third hardground crops out in the Tornimparte village (Latium-Abruzzi platform, Central Apennines) and is early Tortonian in age (ca. 11 Ma; Brandano et al., 2020; Fig. 1). A detailed description of the stratigraphy of the carbonate successions to which these hardgrounds belong as well as log figures and outcrops photographs are provided in the Supplemental Material1.We analyzed seven samples of shark teeth for 143Nd/144Nd ratios. 143Nd/144Nd ratios were measured with the Thermo Triton thermal ionization multicollector mass spectrometer of the Endogene Geodynamic Laboratory of the GeoZentrum Nordbayern (Friedrich-Alexander-Universität Erlangen-Nürnberg [FAU], Erlangen, Germany) after Nd purification.Neodymium isotope data were calibrated against the international La Jolla standard measured with the samples (Fig. 2). Values are corrected for the age of the samples assuming Sm/Nd ratio of fossils is the same as that of seawater (0.122; Piepgras and Wasserburg, 1980). Full details on the sample preparation, Nd purification, and applied corrections are available in the Supplemental Material.The 143Nd/144Nd values are reported as ratios and in εNd notation in Figure 2. They span from εNd -7.5 to εNd -7.1. Thus, not only are the 143Nd/144Nd ratios of the same hardground consistent, but the three hardgrounds show the same signature.The εNd values of the analyzed hardgrounds (εNd -7.5 to -7.1) are similar to those of the deep Indian Ocean, central Paratethys, and North Alpine foreland basin records during the Miocene (Fig. 2A; O'Nions et al., 1998; Kocsis et al., 2009). This similarity is difficult to explain because the Indian Gateway closed in the Burdigalian (ca. 18 Ma) and reopened several times but remained very shallow until its definitive closure at the Langhian-Serravallian boundary (ca. 13.8 Ma; Fig. 3A; Popov et al., 2004). In this context, the Mediterranean εNd remained similar to the Indian Ocean signature (Kocsis et al., 2008; Cornacchia et al., 2018; Bialik et al., 2019). In fact, Bialik et al. (2019), comparing the shallow water record of Malta and the Maldives, stated that the Indian Ocean connection was efficient during the Langhian. However, the modeling study of de la Vara and Meijer (2016) indicated that, after the Burdigalian (ca. 18 Ma), only the shallowest waters entered from the Indian Gateway, switching the Mediterranean circulation from estuarine to antiestuarine. Cornacchia et al. (2018), analyzing the Umbria-Marche basinal succession, hypothesized that water exchanges between the Paratethys—characterized by an εNd similar to that of the Indian Ocean—and the Mediterranean affected the Nd isotopes of the latter. Therefore, the εNd of -7.5 and -7.1 of the upper-most Burdigalian (ca. 16 Ma) hardground on Maiella Mountain might be interpreted as a hint of efficient exchanges with the central Paratethys, which shows the same εNd in that interval (Fig. 2A; Kocsis et al., 2009). However, the comparison of the Nd isotope records, besides proving water exchanges, does not identify the source of the P-rich waters, which might have developed in the North Alpine foreland basin and central Paratethys, as in the deep Mediterranean. Furthermore, according to the paleogeographic reconstructions of the Paratethys (Fig. 3A), only shallow-water exchanges with the Mediterranean occurred, thus potentially influencing the overall Nd isotope fingerprint of the eastern Mediterranean but not directly controlling the deep, P-rich waters forming the upwelling. Furthermore, the Maiella Mountain hardground is late Burdigalian in age (ca. 16 Ma), thus it developed during the MMCO when P availability was enhanced globally due to increased biogeochemical weathering (Föllmi et al., 2008). Lastly, the closure of the Indian Gateway weakened the overall Mediterranean circulation, potentially favoring the onset of deep-water oxygen-depleted zones. In turn, such oxygen-minimum zones favored the return of phosphate from sediments to the water column, creating a positive feedback for hardground formation (Föllmi, 1996).The same influence of the central Paratethys can not be easily inferred for the other two investigated hardgrounds. Simon et al. (2019) stated that at ca. 13.8 Ma, local tectonic changes and a sea-level drop of 50–70 m restricted the exchanges between the Mediterranean and Paratethys, the latter of which passed from open-marine to hypersaline conditions. Furthermore, brackish to freshwater conditions are attested in the shallow portion of the eastern Paratethys and in the gateways with the Mediterranean during the Middle to Late Miocene (Popov et al., 2004; Piller and Harzhauser, 2005; Fig. 3B). However, the Langhian (ca. 12 Ma) and lower Tortonian (ca. 11 Ma) hardgrounds show εNd values between -7.5 and -7.2, thus characterized by a more radiogenic signature in comparison to central Mediterranean values, such as those of the Malta εNd record, that (already across the Langhian-Serravallian boundary; ca. 14 Ma) spanned from -9 to -11 (Bialik et al., 2019; Fig. 2A). Furthermore, the studied hardgrounds are comparable with the Umbria-Marche hemipelagic record (Kocsis et al., 2008; Cornacchia et al., 2018). Kocsis et al. (2008) interpreted these εNd values as a hint of locally evolved Mediterranean deep waters. Wu et al. (2019) reconstructed the Holocene record of the Mediterranean deep and surface waters by analyzing Nd isotopes on fish debris and foraminifera. The authors reported that the Levantine deep waters were significantly more radiogenic (εNd between -5.7 and -7.4) than the western Mediterranean ones (εNd -9.5) because the Strait of Sicily inhibited the eastern deep-water flow. This is also in agreement with Nd isotope data of the Mediterranean margins that show an εNd east-west gradient from ~-7 to ~-12 (Jeandel et al., 2007). de la Vara and Meijer (2016), modeling the Miocene circulation of the Mediterranean, stated that with a shallow or closed Indian Gateway, the onset of an anti-estuarine circulation took place, promoting the exit of Mediterranean deep waters into the Atlantic and favoring a small Atlantic input of surface waters. Furthermore, in the eastern basins, deep waters at >500 m depth remained partially isolated (de la Vara and Meijer, 2016). In this framework, the newly provided Nd isotope data confirm the development of locally evolved Mediterranean waters—characterized by a weak circulation and few exchanges between the deep and the upper levels of the water column—whose chemistry was significantly more affected by regional run-off than by Atlantic input, which is characterized by εNd between -11 and -12 in the Late Miocene (O'Nions et al., 1998; Figs. 2A and 4).Therefore, after the late Burdigalian (ca. 18 Ma), we should assume a Mediterranean circulation similar to that of today, with the deep Mediterranean waters forming within the eastern Mediterranean remaining partially isolated and only the shallow ones flowing westward. This partial isolation of the eastern Mediterranean deep waters explains also the difference between the Nd isotope records of Malta and the investigated successions (Stille et al., 1996; Bialik et al., 2019; Fig. 2A). The Malta Plateau, in fact, has been relatively higher than the surrounding areas since the Mesozoic and experienced a further uplift during the Neogene (Jongsma et al., 1985; Micallef et al., 2016). Thus, the Malta Nd isotope record testifies to a shallower portion of the water column in comparison to the Central Apennines hardgrounds, and the Malta εNd signature is relatively more influenced by the Atlantic inflow. Secondly, the Malta Plateau acted as a barrier for the deep-water currents, limiting the exchanges between the eastern and western Mediterranean. In this context, the Nd isotope record of the Langhian (ca. 12 Ma) to lower Tortonian (ca. 11 Ma) hardgrounds testifies to this major change in the Mediterranean oceanography, i.e., the onset of locally evolved deep waters in the eastern Mediterranean, affected by the regional runoff more than by the adjacent oceans. Furthermore, Karami et al. (2009), modeling the consequences of the closure of the Indian Gateway on Mediterranean circulation, stated that with the Indian Gateway closed, the evaporation in the Mediterranean exceeded the freshwater input, leading to a longer residence time of waters into the basin.Lastly, the Monterey event and the following CM7 perturbation coincided with a strengthening of ocean circulation and intensification of coastal upwelling (Holbourn et al., 2013). For the Mediterranean, after the closure of the Indo-Pacific connection, an oceanographic regime dominated by westward-oriented currents has been proposed by different authors (Moreno et al., 2004; Föllmi et al., 2015; Brandano et al., 2016a). The distinct Nd isotopic fingerprint of the analyzed central Mediterranean hardgrounds testifies to an eastern provenance of the deep waters that formed them. The deep water ascended to the eastern side of the Mediterranean ramps via upwelling before returning to the Atlantic, promoting a significant increase of primary productivity and favoring the development of phosphatic hardgrounds (Föllmi et al., 2008, 2015; Brandano et al., 2016a).The Nd isotope record of three different phosphate-rich hardgrounds developed within Mediterranean shallow-water carbonate successions during the Miocene shows a persistent eastern signature. This record, framed in widely accepted paleogeographic reconstructions of the circum-Mediterranean region, attests to the onset of locally evolved deep waters in the eastern Mediterranean, proving that the closure of the Indo-Pacific connection changed Mediter-ranean circulation, leading to a longer residence time of waters and limited exchanges with the Atlantic Ocean. Lastly, the Nd isotope signature of the analyzed hardgrounds confirms their origin through upwelling of deep water. The onset of the upwelling is related to global climatic changes that affected the Mediterranean area.We are grateful to Editor Kathleen Benison and two anonymous reviewers, whose comments and criticisms significantly improved this manuscript. This research was made possible by the “Visiting Scholarship für Nachwuchswissenschaftlerinnen der Naturwissen-schaftlichen Fakultät” to I. Cornacchia (FAU) and by the “Borsa di studio di perfezionamento all'estero” to I. Cornacchia (Sapienza Università di Roma). We are grateful to M. Regelous for guidance and help in the laboratory for Nd isotopes analyses, to E. Jarochowska for useful advice on how to treat fossil teeth, and to L. Tomassetti for helping in the field and stimulating discussions. The Maiella UNESCO GeoPark is thanked for the license to collect samples.

中文翻译：

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地中海中部磷酸盐硬地的钕同位素揭示了中新世古海洋学

了解硬地形成的原因可以提供有关盆地海洋学演变的见解。中新世期间，富含磷酸盐的硬地层中断了地中海的碳酸盐斜坡沉积。我们分析了地中海中部三个硬地的 εNd 记录，以确定在地中海中新世古海洋学演化框架内形成它们的富含磷酸盐的水域的起源。Nd 同位素表明，与大西洋和印度洋水域相比，地中海东部深水受径流控制。这一 Nd 同位素记录证明，由于印度门户关闭，中新世期间地中海环流减弱。与大西洋浅海水的有限交换导致盆地深水的停留时间较长。这一记录表明了上涌在磷酸盐硬地形成中的作用，并显示了全球气候变化和当地古海洋条件的影响。富含磷酸盐的硬地经常出现在中新世地中海碳酸盐岩层序中，通常与溺水平台和沉积中断有关（Föllmi et al ., 2008, 2015; Brandano 等人, 2020)。对它们形成原因的解释，总体上与磷 (P) 埋藏率的增加有关，从与基质加深、全球气候演变和上升流相关的环流变化，到湿度增加和“洗衣房”事件 (Föllmi, 1996; Mutti 和 Bernoulli，2003；Böhme 等人，2008；Filippelli，2008；Föllmi 等人，2008、2015）。地表水中 P 可用性的增加与初级生产力的提高和碳循环的扰动相一致，碳循环中的正 δ13C 同位素变化证明了这一点。(1) 在渐新世-中新世过渡时期记录了 P 的可用性增强，当时冰川最大值导致风化速率增加（Zachos 等，2001）；（2）在蒙特雷事件期间，中中新世气候最佳期（MMCO）的全球变暖有利于生物地球化学风化（John et al., 2003; Brandano et al., 2017）；(3) 在 Tortonian，当碳最大值 7 (CM7) 扰动与增强的海洋环流速率有关时 (Brandano et al., 2016a, 2020)。地中海地区的地球动力学演化影响了其环流模式，使该盆地对气候变化敏感，并被富含磷酸盐的深水上升流所覆盖，它控制了硬地的发展。确定形成这些硬地的水团对于重建盆地​​的古海洋演化至关重要，即影响地中海初级生产力的主要洋流随时间的变化。然而，已发表的文献忽略了这些水团的起源问题，主要关注硬地层形成与全球 P 循环之间的联系以及养分在碳酸盐台地演化中的作用（例如，Föllmi 等人，2008 年；Brandano 等人） al. 2016a)。钕 (Nd) 同位素是古海洋学变化的可靠代表（Scher 和 Martin，2008 年）。然而，已发表的 Nd 同位素记录主要基于浮游有孔虫，它不记录深水指纹，而是提供来自地表水、底部水和孔隙水的混合信号（Pomiès 等人，2002；Kocsis 等人，2008；Cornacchia 等人，2018）。我们关注硬地鲨鱼牙齿中的 143Nd/144Nd，这是深水团的代表。作为一种稀土元素，Nd 在沉积物-水界面处或附近被掺入磷灰石中，使鲨鱼牙齿中的 143Nd/144Nd 成为海水化学的代表（Scher 和 Martin，2008 年）。这一原则使 Nd 同位素成为确定深水来源的最佳替代品。在这项研究中，之所以选择鲨鱼牙，是因为磷灰石富含 Nd，能抵抗成岩作用，并且是海水化学的可靠代表（Kocsis 等，2009）。因此，这项工作旨在重建在地中海中部三个中新世碳酸盐岩层系中形成硬地的深水团的物源，确定地球动力学对古海洋学和碳酸盐台地溺水的控制。亚平宁山脉（意大利）主要由中新生代石灰岩组成，由深盆地隔开的碳酸盐台地群岛的遗迹（Bernoulli，2001）。所调查的磷酸盐硬地标志着阿普利亚和 Latium-Abruzzi 平台的不同中新世溺水事件（图 1）。在 Maiella 山（Apulian 平台，中亚平宁山脉）的 Fonte del Papa 采石场采集的第一个硬地采样是 Burdigalian 晚期年龄（约 16 Ma；Brandano 等人，2016b；图 1）。第二块硬地出现在巴迪斯科港附近的萨兰托半岛（阿普利亚平台，意大利南部），并且是塞拉瓦利亚晚期（约 12 Ma；Föllmi 等人，2015；图 1）。最后，第三个硬地出现在 Tornimparte 村（Latium-Abruzzi 平台，中亚平宁山脉），年龄为 Tortonian 早期（约 11 Ma；Brandano 等人，2020；图 1）。补充材料 1 中提供了这些硬质地层所属的碳酸盐岩层序的地层学以及测井图和露头照片的详细描述。我们分析了 7 个鲨鱼牙齿样本的 143Nd/144Nd 比率。在 Nd 纯化后，使用 GeoZentrum Nordbayern (Friedrich-Alexander-Universität Erlangen-Nürnberg [FAU], Erlangen, Germany) 的 Endogene Geodynamic Laboratory 的 Thermo Triton 热电离多收集器质谱仪测量 143Nd/144Nd 比率。钕同位素数据根据用样品测量的国际 La Jolla 标准进行校准（图 2）。假设化石的 Sm/Nd 比率与海水相同（0.122；Piepgras 和 Wasserburg，1980），则对样本年龄进行了校正。有关样品制备、Nd 纯化和应用校正的详细信息，请参阅补充材料。143Nd/144Nd 值以比率和 εNd 表示法在图 2 中报告。它们的范围从 εNd -7.5 到 εNd -7.1。因此，不仅同一硬地的 143Nd/144Nd 比率一致，而且三个硬地显示出相同的特征。分析的硬地的 εNd 值（εNd -7.5 到 -7.1）与印度洋深处的相似，中新世期间的Paratethys中部和北高山前陆盆地记录（图2A；O'Nions等人，1998; Kocsis 等人，2009 年）。这种相似性很难解释，因为印度门户在 Burdigalian 关闭（约 18 Ma）并重新打开了几次，但仍然很浅，直到它在 Langhian-Serravallian 边界最终关闭（约 13.8 Ma；图 3A；Popov 等等人，2004 年）。在这种情况下，地中海 εNd 仍与印度洋特征相似（Kocsis 等人，2008 年；Cornacchia 等人，2018 年；Bialik 等人，2019 年）。事实上，Bialik 等人。（2019 年）比较马耳他和马尔代夫的浅水记录，指出在 Langhian 期间印度洋连接是有效的。然而，de la Vara 和 Meijer（2016）的建模研究表明，在 Burdigalian（约 18 Ma）之后，只有最浅的水域从印度门户进入，将地中海环流从河口转向反河口。Cornacchia 等人。（2018 年）在分析翁布里亚-马尔凯盆地演替时，假设 Paratethys（其特征在于与印度洋的 εNd 相似）与地中海之间的水交换影响了后者的 Nd 同位素。因此，Maiella 山最上层 Burdigalian（约 16 Ma）硬地的 -7.5 和 -7.1 的 εNd 可能被解释为与中央 Paratethys 有效交换的暗示，在该区间显示相同的 εNd（图. 2A；Kocsis 等人，2009）。然而，Nd 同位素记录的比较，除了证明水交换之外，并没有确定富磷水的来源，富磷水可能发育在北高山前陆盆地和帕拉提斯中部，如地中海深处。此外，根据对Paratethys的古地理重建（图3A），仅发生与地中海的浅水交换，因此可能影响地中海东部的整体Nd同位素指纹，但不能直接控制形成上升流的富含P的深层水域. 此外，Maiella Mountain 硬地的年龄是 Burdigalian 晚期（约 16 Ma），因此它是在 MMCO 期间发育的，当时由于生物地球化学风化作用增加，全球磷的可用性增强（Föllmi 等，2008）。最后，印度门户的关闭削弱了整个地中海环流，可能有利于深水缺氧区的出现。反过来，这种氧含量最低的区域有利于磷酸盐从沉积物中返回到水体中，从而为硬质地层的形成创造了积极的反馈（Föllmi，1996）。对于其他两个调查的硬地，不能轻易推断出中部Paratethys的相同影响。西蒙等人。（2019 年）表示，在 ca。13.8 Ma, 局部构造变化和海平面下降 50-70 m 限制了地中海和帕拉提斯之间的交流, 后者从开阔海洋过渡到高盐条件。此外，在中新世中新世中晚期，在帕拉提斯东部的浅水部分和通往地中海的通道中证实了咸水到淡水的条件（Popov 等，2004；Piller 和 Harzhauser，2005；图 3B）。然而，Langhian (ca. 12 Ma) 和 Lower Tortonian (ca. 11 Ma) hardground 的 εNd 值在 -7.5 和 -7.2 之间，因此与地中海中部的值相比，其特征在于更具放射性的特征，例如马耳他 εNd 记录的记录（已经跨越 Langhian-Serravallian 边界；约 14 Ma）从 -9 到 -11（Bialik 等人，2019；图 2A）。此外，所研究的硬地与 Umbria-Marche 半远洋记录相当（Kocsis 等人，2008 年；Cornacchia 等人，2018 年）。科西斯等人。(2008) 将这些 εNd 值解释为当地演化的地中海深水的暗示。吴等人。（2019 年）通过分析鱼类碎片和有孔虫的 Nd 同位素，重建了地中海深水和地表水的全新世记录。作者报告说，由于西西里海峡抑制了东部深水流，黎凡特深水的放射性（εNd 在 -5.7 和 -7.4 之间）比地中海西部的深水（εNd -9.5）显着更高。这也与地中海边缘的 Nd 同位素数据一致，该数据显示 εNd 东西梯度从 ~-7 到 ~-12 (Jeandel et al., 2007)。de la Vara 和 Meijer（2016 年）在模拟地中海中新世环流时指出，由于印度门户较浅或封闭，反河口环流的开始发生，促使地中海深水进入大西洋，并有利于少量大西洋输入地表水。此外，在东部盆地，> 500 m 深度的深水仍然部分孤立（de la Vara 和 Meijer，2016）。在这个框架下，地中海东部深水的这种部分隔离也解释了马耳他 Nd 同位素记录与所研究的序列之间的差异（Stille 等，1996；Bialik 等，2019；图 2A）。事实上，马耳他高原自中生代以来一直相对高于周边地区，并在新近纪经历了进一步的隆升（Jongsma et al., 1985; Micallef et al., 2016）。因此，与中亚平宁山脉硬地相比，马耳他 Nd 同位素记录证明了水柱的较浅部分，并且马耳他 εNd 特征相对受大西洋流入的影响更大。其次，马耳他高原是深水洋流的屏障，限制了地中海东部和西部的交流。在此背景下，Langhian 的 Nd 同位素记录（ca. 12 Ma）到较低的 Tortonian（约 11 Ma）硬地证明了地中海海洋学的这一重大变化，即地中海东部局部演化的深水的开始，受区域径流的影响比受邻近海洋的影响更大。此外，Karami 等人。（2009 年）模拟印度门户关闭对地中海环流的影响，指出随着印度门户关闭，地中海的蒸发量超过淡水输入，导致水进入盆地的停留时间更长。最后，蒙特雷事件和随后的 CM7 扰动与海洋环流的加强和沿海上升流的加剧相吻合（Holbourn 等，2013）。对于地中海，在印太连接关闭后，不同的作者已经提出了一个以西向洋流为主的海洋学制度（Moreno et al., 2004; Föllmi et al., 2015; Brandano et al., 2016a）。分析的地中海中部硬地的独特 Nd 同位素指纹证明了形成它们的深水的东部来源。深水通过上升流上升到地中海坡道东侧，然后返回大西洋，促进初级生产力显着提高，有利于磷酸盐硬地的发展（Föllmi et al., 2008, 2015; Brandano et al., 2016a ). 中新世期间在地中海浅水碳酸盐岩层序中发育的三种不同的富含磷酸盐的硬地层的 Nd 同位素记录显示出持续的东部特征。这个记录，以被广泛接受的环地中海地区古地理重建为框架，证明了东地中海局部演化的深水的开始，证明印度-太平洋连接的关闭改变了地中海环流，导致更长的停留时间水域和与大西洋的有限交流。最后，所分析硬地的 Nd 同位素特征通过深水的上升流证实了它们的起源。上升流的开始与影响地中海地区的全球气候变化有关。我们感谢编辑 Kathleen Benison 和两位匿名审稿人，他们的评论和批评大大改善了这份手稿。这项研究是通过对 I. Cornacchia (FAU) 和“Borsa di studio di perfezionamento all'estero” 到 I. Cornacchia (Sapienza Università di Roma)。我们感谢 M. Regelous 在实验室为 Nd 同位素分析提供指导和帮助，感谢 E. Jarochowska 就如何处理牙齿化石提供有用的建议，感谢 L. Tomassetti 在该领域提供帮助并激发讨论。感谢 Maiella UNESCO GeoPark 获得收集样本的许可。