The mid-Atlantic coastal plain (eastern United States) preserves high-resolution records of the Paleocene-Eocene Thermal Maximum (PETM) and attendant carbon isotope excursion (CIE), though preservation is highly variable from site to site. Here, we use a dip transect of expanded (as much as 15 m thick) PETM sections from the New Jersey coastal plain to build a cross-shelf PETM depositional model that explains the variability of these records. We invoke enhanced delivery of fine-grained sediments, due to the rapid environmental changes associated with this hyperthermal event, to explain relatively thick PETM deposits. We utilize δ13Cbulk, percent CaCO3, and percent coarse fraction (>63 μm) data, supported by biostratigraphic records, to correlate sites along a paleoslope dip transect. Updip cores from Medford, New Jersey, preserve expanded sections of the initiation of the PETM and the earliest portion of the CIE. Medial sites (Wilson Lake, Millville) preserve an expanded CIE body, and downdip Bass River records the CIE recovery. We interpret this pattern to reflect the progradation of clinoform foresets across the paleoshelf via fluid mud, similar to modern high-sediment-supply rivers and adjacent muddy shelves (e.g., the Amazon, Mahakam [Indonesia], and Ayeyarwady [Myanmar] Rivers). Our subaqueous-clinoform delta model explains the pattern of the CIE records and provides a framework for future PETM studies in the region.The Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) and attendant carbon isotope excursion (CIE) represent the largest warming event and carbon cycle perturbation of the Cenozoic. Global temperatures rose by 4–8 °C (e.g., Kennett and Stott, 1991; Zachos et al., 2003) while δ13C values decreased by 2‰–4‰ in marine sections (foraminiferal and organic records) and by as much as 7.6‰ in the terrestrial realm (plant lipids) (see McInerney and Wing [2011] for a full review of CIE proxies). Understanding the trigger, rate, and timing of this light-carbon injection is hindered, in part, because most marine CIE-PETM sections are thin (<1 m in 200 k.y.) and thus cannot resolve geologically rapid events (<10 k.y.).The general structure of the CIE is similar globally, beginning with a sharp drop in δ13C values that is used to correlate the base of the Eocene (Paleocene-Eocene boundary) from its stratotype in Dababiya, Egypt (Aubry et al., 2007). In deep-sea sections, the δ13C decrease is sharp (<10 cm), while on continental margin sections, it can be >2 m thick (Figs. 1 –3). A sustained interval of low δ13C values (the body of the CIE) followed the δ13C decrease and was succeeded by a logarithmic return to near pre-CIE δ13C values (the recovery; e.g., Dickens et al., 1997; Röhl et al., 2007). The PETM-CIE lasted ∼200 k.y. from onset to recovery (Dickens et al., 1997; 170 ± 30 k.y. astronomical estimate of Zeebe and Lourens [2019]).The warming associated with the PETM coincided with rapid input of fine-grained sediments to the continental shelf along the mid-Atlantic U.S. continental margin. Thick PETM deposits have been reported on the Maryland (e.g., Self-Trail et al., 2017) and New Jersey coastal plains (NJCP) (e.g., Cramer et al., 1999), which provide greater temporal resolution of the onset and body of the CIE compared to deep-marine settings. Rapid mud deposition on the mid-Atlantic paleoshelf during the PETM has been dubbed the “Appalachian Amazon” (Kopp et al., 2009), characterized by energetic, mud-laden riverine transport and subaqueous dysoxic deposition (Stassen et al., 2012). In the NJCP, uppermost Paleocene Vincentown Formation sands and silts are conformably overlain by the kaolinite-rich clays of the lowermost Eocene Marlboro Formation (Gibson et al., 2000; Cramer et al., 1999) that preserve the CIE.We cored these sediments adjacent to NJCP–PETM outcrops (Medford Auger Project [MAP]; 39.86°N, 74.82°W; Fig. 1; described in the Supplemental Material1) and correlate with PETM sections across a transect recovered in International Ocean Discovery Program (IODP) Leg 174AX sites at Wilson Lake (WL hole B; WL hole A was drilled by the U.S. Geological Survey [USGS]), Millville (MV), and Bass River (BR) (Figs. 2 and 3).These sites each record different parts of the CIE (onset, decrease, body, and recovery) identified by extensive bio- and chemostratigraphic studies (Cramer et al., 1999; Gibbs et al., 2006; Harris et al., 2010; Stassen et al., 2012, 2015; Wright and Schaller, 2013; Makarova et al., 2017). Proximal sites on our transect preserve a notable “transitional unit” that is completely absent in deep-sea sections. This transitional package of sediments preserves the marked shift in grain size, carbonate content, and carbon-isotope geochemistry that signals the rapid change in facies associated with this hyperthermal. These PETM records are greatly expanded (e.g., the CIE body is >10 m thick at WL and MV; Fig. 3), requiring average sedimentation rates exceeding 12.5 cm/k.y. (with estimates as high as 2 cm/yr; Wright and Schaller, 2013), versus ∼4 cm/k.y. background sedimentation rates during Vincentown Formation deposition (Miller et al., 1997).We evaluate CIE heterogeneity on the mid-Atlantic paleoshelf transect and correlate using δ13Cbulk, percent CaCO3, percent coarse fraction (%CF; >63 μm), and nannofossil and benthic foraminiferal biostratigraphy across a paleoslope dip profile spanning 45 km (30–50 m of deepening; Makarova et al., 2017). We do not address the trigger of the PETM, focusing instead on the relationship between rapid warming and sediment input. The differential expression of the CIE across the shelf (shape, thickness, and preserved section at each location) provides a framework of relative time that can later be used to assess proposed mechanisms.In 2016, the MAP continuously cored 10 holes at six closely spaced (<1 km) sites in Medford, New Jersey, targeting updip PETM sections (Fig. 2). This study focuses on two adjacent holes, MAP 3A and MAP 3B (<5 m apart), drilled ∼700 m downdip of the Marlboro Formation outcrop and the IODP Leg 174AX site at Medford (Sugarman et al., 2010), to construct a complete record for site MAP 3 (Fig. 1). A modified depth scale (i.e. meters composite depth; mcd) is applied to adjust for core expansion and is used for correlation between sites MAP 3A and MAP 3B.We measured δ13Cbulk and percent CaCO3 on a Fisons Optima mass spectrometer with an attached Multiprep device in the Rutgers University (New Jersey, USA) stable isotope lab. Sediments taken from MAP cores were washed through a 63 μm sieve to determine %CF. Grain-size analysis was initially conducted via laser diffraction on a Malvern Mastersizer 3000, and later via traditional pipette methods (see the Supplemental Material).The cores from site MAP 3 recovered uppermost Paleocene to lowermost Eocene sands and muds from 14.5 to 19.8 m mcd (Fig. 1). The Vincentown Formation (17.4–19.8 m mcd) is a silty sand interpreted to reflect a lower shoreface facies deposited below fair-weather wave base (see the Supplemental Material). The Marlboro Formation (14.5–16.5 m mcd) is a kaolinitic silty clay (mean grain size <2 μm; Fig. 1; Fig. S2 in the Supplemental Material) deposited in a prodelta setting in middle neritic paleodepths (∼30–50 m; see the Supplemental Material). The transitional unit (16.5–17.4 m mcd) between these two formations is defined by rapidly fining-upward sediments (%CF decreases 72% to 2%). This transitional unit also preserves the rapid change in percent CaCO3 (Fig. 1). At site MAP 3, the transitional unit captures the CIE onset and part of the subsequent CIE decrease. This CIE decrease is extremely sharp in open ocean sites, which, in conjunction with the biostratigraphic correlations, suggests far higher rates of sedimentation on the NJCP: 2.7 m of sediment preserves the CIE onset and initial CIE decrease at hole MAP 3B, versus <10 cm in open-ocean sites.We hang our cross-shelf correlation on the CIE onset, which is coincident with the initial decrease in percent CaCO3 (Fig. 2). Our transect shows clear cross-shelf patterns (Fig. 2). The updip MAP and WL sites preserve distinct transitional units and an expanded view of the onset and start of the CIE decrease (Fig. 3). We cannot make quantitative inferences on sedimentation rates, though δ13C correlations suggest that the onset and decrease sediments recovered at MAP 3 are expanded compared to those at WL (Fig. S1). However, the data sets we have available—comparison of δ13Cbulk records, lithology (uniform silty clay), and benthic assemblages (see below)—argue that site MAP 3 preserves the early part of the CIE decrease and body while the second, more gradual step of the δ13C decrease (seen elsewhere on the NJCP; Fig. 3; Fig. S1) is absent.The transitional unit thins downdip at site MV (Wright and Schaller, 2013; Makarova et al., 2017) and appears to be absent at site BR (Cramer et al., 1999; Fig. 2), where the CIE onset may be diastemic (Stassen et al., 2012). The recovery is apparently completely preserved downdip at site BR, truncated at site MV (Makarova et al., 2017), thin and also incomplete at site WL, and absent updip at site MAP 3 (Fig. 3).Our correlations are reinforced by biostratigraphy. The CIE body is associated with the Rhomboaster-Discoaster (RD) assemblage in the open ocean (Kahn and Aubry, 2004) and in New Jersey (Harris et al., 2010). At downdip sites (MV, BR), the RD assemblage appears at the base of the CIE body, increases sharply to an acme, and decreases in abundance before disappearing in the recovery (Fig. 3; Harris et al., 2010). We do not have access to quantitative data for site WL, however nannofossil biostratigraphy (compiled for hole A in Stassen et al. [2012, 2015] and hole B by Miller et al. [2017]) places the lowest occurrence of Discoaster araneus (a marker of the RD assemblage) at the base of the CIE body (Fig. 3). Benthic foraminiferal assemblages at site MAP 3 are characterized by small individual specimens (<212 μm) and dominated by Anomalinoides acuta and Ammobaculites midwayensis (Makarova, 2018), indicating equivalence to the CIE decrease or body at site WL (Stassen et al., 2015).We explain variability of the sediments of the transitional unit and associated CIE onset and decrease across the shelf as the result of a progrational clinoform delta, with thin sigmoidal topsets, thick foresets, and thin bottomsets (Fig. 3). Though the chronology is known only within a relative time scale of several thousand years, the shift in deposition from site MAP to site WL during the CIE onset and decrease resulted in a 9 km seaward progradation (Fig. 3) in ≤ 4 k.y. (using the chronology of Zeebe and Lourens [2019]) and perhaps much faster (using the chronology of Wright and Schaller [2013]).Evidence for rapid, mud-laden riverine transport and high sedimentation rates includes the lack of bioturbation, physical remnants (vertical sticks and leaves; e.g., Wright and Schaller, 2013), biofacies assemblages (Stassen et al., 2012, 2015), and magnetofossils at least partly indicative of dysoxic environments (Kopp et al., 2009; Wang et al., 2015).In our model, muds originating from the Appalachians, Piedmont, and coastal plain built individual chronostratigraphic units, each preserving a different “snapshot” of the CIE. The earliest packages of fining-upward sand to mud (transitional unit) and overlying clay (Marlboro Formation) captured the CIE onset and initial part of the δ13C decrease (Fig. 3). As accommodation space filled, fluid mud transport drove delta progradation seaward, allowing subsequent clinoform deposition to record the CIE body and recovery (Fig. 3). Meanwhile, updip sections were bypassed and truncated as the seafloor intersected wave base. This produced a regional unconformity capping the Marlboro Formation (Fig. 3; e.g., Gibson et al., 2000). Volume scaling suggests that Amazon shelf–like conditions on the mid-Atlantic coastal plain would have required ∼25% of the modern Amazon sediment flux during the PETM (Kopp et al., 2009).Inferring paleoenvironmental conditions via stratigraphic correlation is subject to some uncertainty due to spatiotemporal variability in sedimentation rates and autocyclical shifts in depocenters (e.g., Trampush and Hajek, 2017; Foreman and Straub, 2017). However, the biostratigraphic, chemostratigraphic, and lithologic trends demonstrated in this study (Fig. 2) are consistent with our progradational depositional model, whether that trend is predicted to disappear proximally and expand in a downdip direction (CIE body and recovery, percent RD influx [the sediments preserving the appearance of RD]) or, in contrast, disappear distally with expanded sections updip (CIE decrease, low-carbonate zone). We acknowledge that our sedimentary records may not be complete, which could have resulted in an incomplete depiction of a three-dimensional, lobe-shaped geometry on our two-dimensional cross section. However, the consistent patterns observed across the transect (Figs. 2 and 3) support this general pattern of sedimentation.This rapid progradational mud system explains the relative distribution of biofacies, the variable expression of the CIE, and the lithology on the NJCP. The high sedimentation rates on the mid-Atlantic paleoshelf have been attributed to the warm subtropical PETM climate, analogous to that of the modern Amazon (e.g., Nittrouer et al., 1995) and other high-input rivers (e.g., Mahakam [Indonesia], Ayeyarwady [Myanmar]). Modern subaqueous clinoform deltas are associated with large mud-laden riverine systems around the globe, including the Ganges-Brahmaputra (India and Bangladesh; Kuehl et al., 2005), Fly (Papua New Guinea; Walsh et al., 2004), Yangtze (China; Chen et al., 2000), Mahakam (Storms et al., 2005), and Ayeyarwady (Liu et al., 2020) Rivers. These delta systems all share two critical conditions: high input of muddy riverine sediments, and an energetic tide- or storm-dominated environment to facilitate transport.In particular, we identify the Holocene Amazon, Mahakam, and Ayeyarwady river systems as important case studies for drawing modern analogs for the Marlboro Formation clinoforms. Observations in these systems detail how muds coalesce and accumulate in topset depocenters under tidal and wave forces and are then episodically transported across the shelf by fluid mud processes (e.g., on the Amazon delta; Kineke et al., 1996). Using these analogs, we invoke rapid fluid mud deposition as the transport mechanism for delta mud clinoforms on the NJCP during the PETM.Cross-shelf movement of fluid mud requires an energetic transport mechanism (i.e., tides or storms). On the Holocene storm-dominated mid-Atlantic continental shelf, clay sediments are trapped in estuaries, while mud that reaches the shelf is swept into the deep sea by energetic storms (Miller et al., 2014). Though the PETM differed climatologically (lower latitudinal gradients), the high supply of mud accumulated in the shallow embayment, where storms and tides facilitated transport to the foresets and bottomsets, as observed in modern mud-rich systems (Nittrouer et al., 1995; Storms et al., 2005; Liu et al., 2020).Our PETM depositional model suggests progradation rates similar to those observed in Holocene high-sediment-supply river systems. For example, the Holocene Mahakam delta has prograded ∼60 km into the Makassar Strait over the past 5000 yr (∼12 km/k.y.; Storms et al., 2005), while our model suggests 45 km of progradation during the geologically brief PETM (Fig. 3). Thus, we incorporate modern studies of muddy river systems to evaluate the distribution of these PETM clays. This approach provides a mechanism that explains the variability in the preservation of the CIE in this region and a blueprint for planning future studies.Geochemical, sedimentological, and biostratigraphic records demonstrate that deposition on the New Jersey paleoshelf during the PETM consisted of prograding depocenters. A strengthened hydrological cycle bolstered riverine transport of muds to the paleoshelf. We explain the variability of the CIE records observed on our cross-shelf transect using a progradational clinoform depositional model supported by cross-shelf correlations of multiproxy lithologic, biostratigraphic, and δ13Cbulk data. Proximal (updip) sites record high fluxes of sediments during the CIE onset, which rapidly filled available accommodation space, forcing clinoforms to prograde into deeper water. Our PETM progradational model illuminates the influence of transient warming events on continental shelves and presents a qualitative chronostratigraphic tool for correlating PETM sites across the mid-Atlantic paleoshelf and for selecting future drill-site locations based on CIE target intervals.We thank the late C. Lombardi, who proposed the possibility of fluid mud deposition on the New Jersey coastal plain during the PETM; the U.S. Geological Survey drillers, particularly the late J. Grey, for their efforts; the International Ocean Discovery Program for samples from Leg 174AX sites; as well as the anonymous reviewers who, alongside Elizabeth Hajek, contributed feedback that greatly enhanced the strength of this paper. This work was supported by U.S. National Science Foundation grants OCE16-57013 (Miller) and OCE14-63759 (Miller and Browning).

中文翻译：

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清澈如泥：古新世-始新世最大热事件的斜形进积和扩展记录

大西洋中部沿海平原（美国东部）保留了古新世-始新世热最大值 (PETM) 和随之而来的碳同位素偏移 (CIE) 的高分辨率记录，尽管不同地点的保存情况差异很大。在这里，我们使用新泽西沿海平原的扩展（高达 15 m 厚）PETM 剖面的倾斜横断面来构建跨陆架 PETM 沉积模型，以解释这些记录的可变性。由于与这种高温事件相关的快速环境变化，我们援引细粒沉积物的增强输送来解释相对较厚的 PETM 沉积物。我们利用由生物地层记录支持的 δ13Cbulk、CaCO3 百分比和粗颗粒百分比 (>63 μm) 数据来关联古斜坡倾斜横断面的站点。来自新泽西州梅德福的 Updip 核心，保留 PETM 启动的扩展部分和 CIE 的最早部分。内侧站点（威尔逊湖、米尔维尔）保留了扩大的 CIE 主体，而下倾的巴斯河记录了 CIE 恢复。我们解释这种模式是为了反映通过流体泥浆在古陆架上的斜状前移，类似于现代高沉积物供应河流和相邻的泥质陆架（例如，亚马逊河、马哈坎 [印度尼西亚] 和伊洛瓦底 [缅甸] 河流）。我们的水下斜面三角洲模型解释了 CIE 记录的模式，并为该地区未来的 PETM 研究提供了框架。古新世-始新世热最大值 (PETM; 56 Ma) 和伴随的碳同位素偏移 (CIE) 代表了最大的变暖事件和新生代碳循环扰动。全球温度上升了 4–8 °C（例如，Kennett 和 Stott，1991；Zachos 等人，2003 年），而海洋部分（有孔虫和有机记录）的 δ13C 值下降了 2‰–4‰，而陆地领域（植物脂质）的 δ13C 值下降了 7.6‰（参见 McInerney 和 Wing [2011]对 CIE 代理的全面审查）。了解这种轻碳注入的触发、速率和时间受到阻碍，部分原因是大多数海洋 CIE-PETM 剖面都很薄（200 ky 中 <1 m），因此无法解析地质快速事件（<10 ky）。 CIE 的一般结构在全球范围内是相似的，首先是 δ13C 值急剧下降，该值用于将始新世的底部（古新世-始新世边界）与其在埃及达巴比亚的层型相关联（Aubry 等，2007）。在深海剖面，δ13C 下降幅度很大（<10 cm），而在大陆边缘剖面，其厚度可能大于 2 m（图 1-3）。低 δ13C 值（CIE 的主体）的持续间隔跟随 δ13C 下降，随后对数返回到接近 CIE 之前的 δ13C 值（恢复；例如，Dickens 等人，1997 年；Röhl 等人， 2007）。PETM-CIE 从开始到恢复持续了约 200 ky（Dickens 等人，1997 年；Zeebe 和 Lourens 的 170 ± 30 ky 天文估计 [2019]）。与 PETM 相关的变暖恰逢细粒沉积物的快速输入到美国大西洋中部大陆边缘的大陆架。在马里兰州（例如，Self-Trail 等人，2017 年）和新泽西州沿海平原 (NJCP)（例如，Cramer 等人，1999 年）上已经报道了厚的 PETM 沉积物，它们提供了更大的发病和身体的时间分辨率CIE 与深海环境相比。PETM 期间大西洋中部古陆架上的快速泥浆沉积被称为“阿巴拉契亚亚马逊河”（Kopp 等人，2009 年），其特征是充满活力的、充满泥浆的河流运输和水下缺氧沉积（Stassen 等人，2012 年） . 在 NJCP 中，最上层的古新世 Vincenttown 地层砂和淤泥被最下层始新世 Marlboro 组（Gibson 等人，2000 年；Cramer 等人，1999 年）的富含高岭石的粘土一致覆盖，保留了 CIE。我们对这些沉积物进行了取芯毗邻 NJCP-PETM 露头（梅德福俄歇项目 [MAP]；39.86°N，74.82°W；图 1；在补充材料 1 中描述）并与国际海洋发现计划 (IODP) 航段中恢复的横断面的 PETM 剖面相关联威尔逊湖的 174AX 站点（WL 孔 B；WL 孔 A 由美国地质调查局 [USGS] 钻探），米尔维尔（MV），和巴斯河 (BR)（图 2 和 3）。这些站点分别记录了 CIE 的不同部分（开始、减少、主体和恢复），这些部分由广泛的生物和化学地层研究确定（Cramer 等人，1999 年；Gibbs等，2006；Harris 等，2010；Stassen 等，2012、2015；Wright 和 Schaller，2013；Makarova 等，2017）。我们横断面上的邻近站点保留了一个显着的“过渡单元”，在深海部分完全不存在。这种过渡性沉积物保留了颗粒大小、碳酸盐含量和碳同位素地球化学的显着变化，这标志着与这种高温相关的相的快速变化。这些 PETM 记录大大扩展（例如，在 WL 和 MV 处 CIE 体的厚度 >10 m；图 3），要求平均沉降速率超过 12.5 cm/ky（估计高达 2 cm/yr；Wright 和 Schaller，2013 年），与 Vincenttown 地层沉积过程中的 ∼4 cm/ky 背景沉积速率（Miller 等人，1997 年）相比。我们评估了大西洋中部古陆架横断面的 CIE 非均质性，并使用 δ13Cbulk、CaCO3 百分比、粗颗粒百分比进行关联分数（%CF；>63 μm），以及跨越 45 公里（加深 30-50 米；Makarova 等人，2017 年）的古斜坡倾角剖面的纳米化石和底栖有孔虫生物地层学。我们不解决 PETM 的触发问题，而是关注快速变暖和沉积物输入之间的关系。整个架子上 CIE 的差异表达（每个位置的形状、厚度和保存部分）提供了一个相对时间框架，以后可用于评估提出的机制。 2016 年，MAP 连续在 6 个紧密间隔的 10 个孔中取芯(< 1 公里）位于新泽西州梅德福的站点，针对向上倾斜的 PETM 部分（图 2）。这项研究的重点是两个相邻的孔，MAP 3A 和 MAP 3B（相距 <5 m），在 Medford 的万宝路地层露头和 IODP Leg 174AX 站点钻探约 700 m 下倾角（Sugarman 等，2010），以构建一个站点 MAP 3 的完整记录（图 1）。修改后的深度刻度（即米复合深度；mcd）用于调整岩心膨胀，并用于位点 MAP 3A 和 MAP 3B 之间的相关性。我们在 Fisons Optima 质谱仪上测量了罗格斯大学（美国新泽西州）稳定同位素实验室。将取自 MAP 岩心的沉积物通过 63 μm 筛子洗涤以确定 %CF。粒度分析最初是在 Malvern Mastersizer 3000 上通过激光衍射进行的，后来通过传统的移液管方法（参见补充材料）。来自 MAP 3 站点的岩心从 14.5 到 19.8 mcd 恢复了最上层的古新世到最下层的始新世砂和泥（图 1）。Vincenttown 组 (17.4–19.8 mcd) 是一种粉砂质沙，解释为反映了沉积在晴天海浪底部下方的较低岸面相（参见补充材料）。万宝路组（14.5-16.5 mcd）是一种高岭质粉质粘土（平均粒度<2 μm；图1；补充材料中的图S2）沉积在中浅海古深度（~30-50 m）的前三角洲环境中；见补充材料）。这两个地层之间的过渡单元 (16.5–17.4 m mcd) 由快速向上的沉积物定义（%CF 减少 72% 至 2%）。该过渡单元还保留了 CaCO3 百分比的快速变化（图 1）。在站点 MAP 3，过渡单元捕获 CIE 开始和后续 CIE 减少的一部分。这种 CIE 下降在开阔的海洋地点极其急剧，结合生物地层相关性，表明 NJCP 上的沉积速率要高得多：2.7 m 的沉积物保留了孔 MAP 3B 处的 CIE 起始和初始 CIE 下降，而 <10厘米。我们将跨大陆架相关性挂在 CIE 开始上，这与 CaCO3 百分比的初始下降一致（图 2）。我们的横断面显示出清晰的跨货架模式（图 2）。上倾 MAP 和 WL 位点保留了不同的过渡单元和 CIE 下降开始和开始的扩展视图（图 3）。我们无法对沉降速率进行定量推断，尽管 δ13C 相关性表明在 MAP 3 恢复的起始和减少沉积物与 WL 相比有所扩大（图 S1）。然而，我们可用的数据集——δ13Cbulk 记录的比较、岩性（均匀粉质粘土）和底栖组合（见下文）——认为 MAP 3 站点保留了 CIE 减少和主体的早期部分，而第二个更渐进的δ13​​C 减少的步骤（在 NJCP 的其他地方看到；图 3；图 S1）不存在。过渡单元在 MV 站点变薄下倾角（Wright 和 Schaller，2013 年；Makarova 等人，2017 年）并且似乎不存在在 BR 位点（Cramer 等人，1999 年；图 2），其中 CIE 开始可能是离散的（Stassen 等人，2012 年）。恢复显然在 BR 站点完全保留下倾，在 MV 站点被截断（Makarova 等，2017），在站点 WL 薄且不完整，并且在站点 MAP 3 处没有上升（图 3）。我们的相关性通过生物地层学得到了加强。CIE 体与公海（Kahn 和 Aubry，2004 年）和新泽西州（Harris 等人，2010 年）中的 Rhomboaster-Discoaster (RD) 组合有关。在下倾位置（MV、BR），RD 组合出现在 CIE 体的底部，急剧增加到顶点，然后在恢复中消失之前丰度减少（图 3；Harris 等，2010）。我们无法获得站点 WL 的定量数据，但是纳米化石生物地层学（为 Stassen 等人 [2012, 2015] 中的孔 A 和 Miller 等人 [2017] 中的孔 B 编译）将 Discoaster araneus 的发生率最低（ RD 组合的标记）在 CIE 主体的底部（图 3）。MAP 3 站点的底栖有孔虫组合的特点是个体样本较小（< 212 μm) 并以 Anomalinoides acuta 和 Ammobaculites midwayensis (Makarova, 2018) 为主（Makarova, 2018），表明等效于 WL 站点的 CIE 减少或本体（Stassen 等，2015）。我们解释了过渡单元和相关 CIE 沉积物的变异性由于渐进式斜交三角洲，在陆架上开始和下降，具有薄的 S 形顶峰、厚的前缘和薄的底缘（图 3）。尽管年代学仅在几千年的相对时间尺度内已知，但在 CIE 开始和减少期间，沉积从 MAP 站点到 WL 站点的转变导致 ≤ 4 ky（使用Zeebe 和 Lourens [2019] 的年表），也许更快（使用 Wright 和 Schaller [2013] 的年表）。快速的证据，充满泥浆的河流运输和高沉积率包括缺乏生物扰动、物理残余物（垂直的枝条和树叶；例如，Wright 和 Schaller，2013 年）、生物相组合（Stassen 等人，2012 年、2015 年）和至少部分的磁化石指示缺氧环境（Kopp 等人，2009 年；Wang 等人，2015 年）。在我们的模型中，源自阿巴拉契亚山脉、皮埃蒙特和沿海平原的泥浆构建了单独的年代地层单元，每个单元都保存了 CIE 的不同“快照” . 最早的向上向上细化成泥（过渡单元）和上覆粘土（万宝路组）的包捕获了 CIE 开始和 δ13C 下降的初始部分（图 3）。随着容纳空间的填满，流体泥浆输送推动三角洲向海进积，允许随后的 clinoform 沉积记录 CIE 主体和恢复（图 3）。同时，随着海底与波基相交，上倾部分被绕过和截断。这产生了覆盖万宝路组的区域不整合面（图 3；例如 Gibson 等，2000）。体积缩放表明，在 PETM 期间，大西洋中部沿海平原上类似亚马逊大陆架的条件需要约 25% 的现代亚马逊沉积物通量（Kopp 等人，2009 年）。通过地层相关性推断古环境条件受制于一些由于沉积速率的时空变异性和沉积中心的自循环变化造成的不确定性（例如，Trampush 和 Hajek，2017 年；Foreman 和 Straub，2017 年）。然而，本研究显示了生物地层学、化学地层学和岩性趋势（图 1）。2) 与我们的进积沉积模型一致，无论该趋势预计会在近端消失并向下倾方向扩展（CIE 体和恢复、RD 流入百分比 [保留 RD 外观的沉积物]），还是相反地向远端消失扩大部分上倾（CIE 减少，低碳区）。我们承认我们的沉积记录可能不完整，这可能导致我们二维横截面的 3 维、叶形几何结构的描绘不完整。然而，横断面观察到的一致模式（图 2 和 3）支持这种一般的沉积模式。这种快速进积泥浆系统解释了生物相的相对分布、CIE 的可变表达以及 NJCP 上的岩性。大西洋中部古陆架的高沉积率归因于温暖的亚热带 PETM 气候，类似于现代亚马逊（例如，Nittrouer 等，1995）和其他高输入河流（例如，Mahakam [印度尼西亚]） , 伊洛瓦底 [缅甸])。现代水下倾斜三角洲与全球大型泥浆河流系统有关，包括恒河-布拉马普特拉河（印度和孟加拉国；Kuehl 等人，2005 年）、弗莱（巴布亚新几内亚；Walsh 等人，2004 年）、长江(China; Chen et al., 2000), Mahakam (Storms et al., 2005), and Ayeyarwady (Liu et al., 2020) Rivers。这些三角洲系统都有两个关键条件：泥泞的河流沉积物的大量输入，以及有利于运输的充满活力的潮汐或风暴主导的环境。和伊洛瓦底江系统作为绘制万宝路地层斜面现代类似物的重要案例研究。在这些系统中的观察详细说明了泥浆如何在潮汐和波浪力作用下在上层沉积中心聚结和积累，然后通过流体泥浆过程（例如，在亚马逊三角洲；Kineke 等人，1996 年）不时地穿过陆架。使用这些类似物，我们将快速流体泥浆沉积作为 PETM 期间 NJCP 上三角洲泥浆斜面的传输机制。流体泥浆的跨架运动需要一个能量传输机制（即潮汐或风暴）。在全新世风暴主导的大西洋中部大陆架上，粘土沉积物被困在河口，而到达大陆架的泥浆则被高能风暴卷入深海（Miller 等，2014）。尽管 PETM 在气候上有所不同（较低的纬度梯度），但在浅海湾中积累了大量的泥浆，在那里风暴和潮汐促进了向前海和海床的运输，正如在现代富含泥浆的系统中所观察到的那样（Nittrouer 等人，1995 年； Storms 等人，2005 年；Liu 等人，2020 年。我们的 PETM 沉积模型表明，进积速率与在全新世高沉积物供应河流系统中观察到的相似。例如，全新世 Mahakam 三角洲在过去 5000 年中已向望加锡海峡进积约 60 公里（约 12 公里/公里；Storms 等人，2005 年），而我们的模型表明在地质短暂的 PETM 期间有 45 公里的进积（图 3)。因此，我们结合对泥泞河流系统的现代研究来评估这些 PETM 粘土的分布。这种方法提供了一种机制，解释了该地区 CIE 保存的可变性，并为规划未来研究提供了蓝图。地球化学、沉积学和生物地层记录表明，PETM 期间新泽西古陆架上的沉积包括进阶沉积中心。加强的水文循环促进了泥浆向古陆架的河流运输。我们使用由多代理岩性、生物地层和 δ13Cbulk 数据的跨陆架相关性支持的进积倾斜沉积模型来解释在我们的跨陆架横断面上观察到的 CIE 记录的可变性。近端（上倾）位点在 CIE 开始时记录了沉积物的高通量，这些沉积物迅速填满了可用的容纳空间，迫使斜形体前进到更深的水中。我们的 PETM 进积模型阐明了瞬态变暖事件对大陆架的影响，并提供了一种定性年代地层学工具，用于关联大西洋中部古陆架的 PETM 站点以及根据 CIE 目标间隔选择未来的钻探站点位置。我们感谢晚 C. Lombardi，他提出了在 PETM 期间新泽西沿海平原发生流体泥浆沉积的可能性；美国地质调查局钻井人员，特别是已故的 J. Grey，感谢他们的努力；来自 Leg 174AX 站点的样本的国际海洋发现计划；以及与 Elizabeth Hajek 一起提供反馈的匿名审稿人，大大增强了本文的实力。这项工作得到了美国国家科学基金会 OCE16-57013（米勒）和 OCE14-63759（米勒和布朗宁）的支持。