大北美中洲泥盆纪-密西西比泥岩碎屑的风尘起源--回复

IF 2 4区 地球科学 Q1 GEOLOGY
Austin J. McGlannan, Alicia Bonar, Lily Pfeifer, Sebastian Steinig, Paul Valdes, Steven Adams, David Duarte, Benmadi Milad, Andrew Cullen, Gerilyn S. Soreghan
{"title":"大北美中洲泥盆纪-密西西比泥岩碎屑的风尘起源--回复","authors":"Austin J. McGlannan, Alicia Bonar, Lily Pfeifer, Sebastian Steinig, Paul Valdes, Steven Adams, David Duarte, Benmadi Milad, Andrew Cullen, Gerilyn S. Soreghan","doi":"10.2110/jsr.2023.122","DOIUrl":null,"url":null,"abstract":"We thank Wilson and Schieber for their discussion, as our paper in Current Ripples presented a new hypothesis, and we welcome tests of that hypothesis. Current Ripples encourages “provocative papers on sedimentary geology” so we are happy to motivate future research toward advancing knowledge on the Devono-Mississippian of North America.Through an integration of paleogeography, paleoclimate, grain size, detrital-zircon provenance, geochemistry, and surface-wind models, McGlannan et al. (2022) proposed that eolian transport supplied significant siliciclastic material to Devono-Mississippian marine strata of the North American midcontinent. Wilson and Schieber (2024) begin their discussion with the statement that “…extrapolating the inferred sedimentary dynamics of one stratigraphic interval (Early Mississippian) across a sequence boundary to rocks that were deposited multiple millions of years earlier (Late Devonian) is neither recommended nor considered good practice.” We find this odd, akin to arguing that, e.g., sediment dynamics of glacioeustasy in the Pleistocene cannot apply to glacioeustasy that operated in the Pennsylvanian. Processes can apply across time, as long as the tenets of uniformity of process (uniformitarianism) are followed. Wilson and Schieber (2024) then focus on three main arguments to challenge the validity of our hypothesis for the Late Devonian in particular.Regarding the issue of an authigenic or detrital origin for the silica, we recognize that Schieber and his collaborators have extensive experience with mudstone petrography and petrology, are aware of and respect their work documenting diagenetic silica in mudstones, and indeed acknowledge in our paper the pervasive presence of diagenetic and biogenic silica in the Woodford Shale. For example, Figure 5B in McGlannan et al. (2022) illustrates the rhythmic, thin, chert-like beds in the Woodford Shale. Wilson and Schieber note that they have studied samples from the same sites we studied and found diagenetic silica. We do not doubt this. Owing to the common presence of diagenetic silica, we preferentially avoided silica-rich facies and predominantly sampled laminated shale facies. Wilson and Schieber (2024) suggest that we generated sand- and silt-size particles “upon crushing–processing” but, as we detailed in our paper, “Samples were gently crushed with a ceramic mortar and pestle to pea-size gravel to accelerate chemical reactions, then rinsed with distilled water and sieved at 250 μm to remove any fines generated during crushing” that might be erroneously incorporated in the grain-size analyses. Of 19 Woodford Shale samples, 12 were selected for particle-size measurement after smear-slide analysis to verify disaggregation and presence of a preponderance of detrital material (Supplemental File 3 and Fig. 6A in McGlannan et al. 2022), which included not only quartz, but minor feldspar and even (rare) accessory minerals such as zircon. We acknowledge that, despite our efforts to minimize the inclusion of diagenetic silica, some microcrystallized silica may have remained, which would have skewed particle-size results to finer modes. Additionally, as discussed in our paper, eolian delivery of silica-rich dust likely provided a significant source of Si for biogenic and diagenetic silica in these Devono-Mississippian units—an interpretation that builds on previous work by others, such as Banks (1970), Cecil (2015), and Cecil et al. (2018).Wilson and Schieber (2024) then address stratigraphic relationships, implying that we believe the Woodford (and correlative black shales) should exhibit a draping geometry owing to hemipelagic settling, but we do not, in any way, dispute a component of bottom-current transport for the redistribution of detrital material in the Woodford Shale or any of its correlative formations. We absolutely acknowledge the action of submarine redeposition and redistribution. We mention several times throughout the paper that these sediments were ultimately deposited in the marine environment, but we hypothesize eolian delivery of the material to the marine system. Once eolian dust hits the surface waters, it is subject to marine processes, especially if accumulation occurs on submarine slopes. Analogous systems wherein submarine mass flows redistributed eolian-transported fines include the sandstones and siltstones of the Permian Delaware Mountain Group, for example (Fischer and Sarnthein 1988).We do not doubt the existence of stratigraphic complexities related to basin dynamics and sea-level fluctuations. Stratigraphic complexities in the Woodford Shale related to relative changes in base level are certainly present in Oklahoma, but the comparison of these complexities to those in the Appalachian foreland basin and the intracratonic Illinois and Michigan basins requires much further stratigraphic study. During the Late Devonian the Anadarko basin was essentially a wide passive margin facing southward into the Rheic Sea. Although there appears to be an intra-Woodford unconformity at the Devonian–Carboniferous boundary, the continuity in conodont and pollen biozones at the I-35 South outcrop in Oklahoma (Over 1990, 1992; Kondas et al. 2018) and conodont zones at the Wapanucka (Over 1990), and Hass G (Boardman and Puckette 2006; Haywa-Branch and Barrick 1990; Over and Barrick 1990) locations demonstrate that the Upper Woodford unconformity is of a lower magnitude than certain regions in the up-dip interior Illinois basin (Over et al. 2019; Over 2021; Fig. 6 in Lazar and Schieber 2022). Yet, the sediments are similar; therefore eolian delivery provides a viable means for transporting sediments beyond the Appalachian system.In their third major point, Wilson and Schieber (2024) take issue with the hypothesis of eolian nutrient fertilization. Regarding nutrients supplied to Devonian epeiric seas, we accept the possibility of eutrophication from the expansion of terrestrial land plants, and deep basin upwelling, in addition to eolian dust fertilization. We did not exclude any mechanism by which nutrients might have reached the marine system. Rather, we merely suggested dust as a possible carrier of iron, in light of the eolian hypothesis. We are raising questions and proposing hypotheses to consider. We do not know how significant dust may (or may not) have been in delivering nutrients (bioavailable iron) across Laurentian epeiric seas during the Late Devonian. Mechanisms of nutrient delivery are not mutually exclusive. In other words, sometimes the answer isn’t either/or, but both, or all the above.Finally, we disagree with Wilson and Schieber’s (2024) argument on the requirement for “a commensurate concentration of sand and formation of eolian dunes” to generate “copious quantities of dust.” As addressed in our paper, whilst much controversy surrounds the claim that sand dunes and eolian processes produce significant dust deposits, both empirical and experimental studies raise questions about the efficacy of sand saltation in producing silt, and this remains a contentious claim. For example, although sand saltation has been suggested for small loess accumulations such as the Negev in Israel (Crouvi et al. 2008), relatively minimal eolian silt (loess) occurs in the peri-Saharan region, for example (Smalley 1995)—where one might expect large volumes given the vast sand seas. Furthermore, recent experimental studies demonstrate the inefficiency of eolian saltation of sand for silt production (Swet et al. 2019, 2020; Adams and Soreghan 2020). Consider that the dustiest source on the planet today, the Bodélé Depression, is not sourced by dunes, but by the desiccated-lake deposits of paleolake Megachad (Warren et al. 2007). Similarly, dust off the Copper River Delta today is sourced by the deflation of glacially generated fines across (dried) floodplains, not sand dunes (Crusius et al. 2011).We again thank Wilson and Schieber for the opportunity for additional discussion, and for highlighting the need for further petrographic and SEM studies of the Woodford Shale focused specifically on the detrital component. It is likely we will continue to agree to disagree on several points; even so, we look forward to further testing and revision of our hypothesis that eolian-transported detrital silt and dust contributed to the Woodford Shale, and many of its correlatives.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"An eolian dust origin for clastic fines of Devono-Mississippian mudrocks of the greater North American midcontinent—Reply\",\"authors\":\"Austin J. McGlannan, Alicia Bonar, Lily Pfeifer, Sebastian Steinig, Paul Valdes, Steven Adams, David Duarte, Benmadi Milad, Andrew Cullen, Gerilyn S. Soreghan\",\"doi\":\"10.2110/jsr.2023.122\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We thank Wilson and Schieber for their discussion, as our paper in Current Ripples presented a new hypothesis, and we welcome tests of that hypothesis. Current Ripples encourages “provocative papers on sedimentary geology” so we are happy to motivate future research toward advancing knowledge on the Devono-Mississippian of North America.Through an integration of paleogeography, paleoclimate, grain size, detrital-zircon provenance, geochemistry, and surface-wind models, McGlannan et al. (2022) proposed that eolian transport supplied significant siliciclastic material to Devono-Mississippian marine strata of the North American midcontinent. Wilson and Schieber (2024) begin their discussion with the statement that “…extrapolating the inferred sedimentary dynamics of one stratigraphic interval (Early Mississippian) across a sequence boundary to rocks that were deposited multiple millions of years earlier (Late Devonian) is neither recommended nor considered good practice.” We find this odd, akin to arguing that, e.g., sediment dynamics of glacioeustasy in the Pleistocene cannot apply to glacioeustasy that operated in the Pennsylvanian. Processes can apply across time, as long as the tenets of uniformity of process (uniformitarianism) are followed. Wilson and Schieber (2024) then focus on three main arguments to challenge the validity of our hypothesis for the Late Devonian in particular.Regarding the issue of an authigenic or detrital origin for the silica, we recognize that Schieber and his collaborators have extensive experience with mudstone petrography and petrology, are aware of and respect their work documenting diagenetic silica in mudstones, and indeed acknowledge in our paper the pervasive presence of diagenetic and biogenic silica in the Woodford Shale. For example, Figure 5B in McGlannan et al. (2022) illustrates the rhythmic, thin, chert-like beds in the Woodford Shale. Wilson and Schieber note that they have studied samples from the same sites we studied and found diagenetic silica. We do not doubt this. Owing to the common presence of diagenetic silica, we preferentially avoided silica-rich facies and predominantly sampled laminated shale facies. Wilson and Schieber (2024) suggest that we generated sand- and silt-size particles “upon crushing–processing” but, as we detailed in our paper, “Samples were gently crushed with a ceramic mortar and pestle to pea-size gravel to accelerate chemical reactions, then rinsed with distilled water and sieved at 250 μm to remove any fines generated during crushing” that might be erroneously incorporated in the grain-size analyses. Of 19 Woodford Shale samples, 12 were selected for particle-size measurement after smear-slide analysis to verify disaggregation and presence of a preponderance of detrital material (Supplemental File 3 and Fig. 6A in McGlannan et al. 2022), which included not only quartz, but minor feldspar and even (rare) accessory minerals such as zircon. We acknowledge that, despite our efforts to minimize the inclusion of diagenetic silica, some microcrystallized silica may have remained, which would have skewed particle-size results to finer modes. Additionally, as discussed in our paper, eolian delivery of silica-rich dust likely provided a significant source of Si for biogenic and diagenetic silica in these Devono-Mississippian units—an interpretation that builds on previous work by others, such as Banks (1970), Cecil (2015), and Cecil et al. (2018).Wilson and Schieber (2024) then address stratigraphic relationships, implying that we believe the Woodford (and correlative black shales) should exhibit a draping geometry owing to hemipelagic settling, but we do not, in any way, dispute a component of bottom-current transport for the redistribution of detrital material in the Woodford Shale or any of its correlative formations. We absolutely acknowledge the action of submarine redeposition and redistribution. We mention several times throughout the paper that these sediments were ultimately deposited in the marine environment, but we hypothesize eolian delivery of the material to the marine system. Once eolian dust hits the surface waters, it is subject to marine processes, especially if accumulation occurs on submarine slopes. Analogous systems wherein submarine mass flows redistributed eolian-transported fines include the sandstones and siltstones of the Permian Delaware Mountain Group, for example (Fischer and Sarnthein 1988).We do not doubt the existence of stratigraphic complexities related to basin dynamics and sea-level fluctuations. Stratigraphic complexities in the Woodford Shale related to relative changes in base level are certainly present in Oklahoma, but the comparison of these complexities to those in the Appalachian foreland basin and the intracratonic Illinois and Michigan basins requires much further stratigraphic study. During the Late Devonian the Anadarko basin was essentially a wide passive margin facing southward into the Rheic Sea. Although there appears to be an intra-Woodford unconformity at the Devonian–Carboniferous boundary, the continuity in conodont and pollen biozones at the I-35 South outcrop in Oklahoma (Over 1990, 1992; Kondas et al. 2018) and conodont zones at the Wapanucka (Over 1990), and Hass G (Boardman and Puckette 2006; Haywa-Branch and Barrick 1990; Over and Barrick 1990) locations demonstrate that the Upper Woodford unconformity is of a lower magnitude than certain regions in the up-dip interior Illinois basin (Over et al. 2019; Over 2021; Fig. 6 in Lazar and Schieber 2022). Yet, the sediments are similar; therefore eolian delivery provides a viable means for transporting sediments beyond the Appalachian system.In their third major point, Wilson and Schieber (2024) take issue with the hypothesis of eolian nutrient fertilization. Regarding nutrients supplied to Devonian epeiric seas, we accept the possibility of eutrophication from the expansion of terrestrial land plants, and deep basin upwelling, in addition to eolian dust fertilization. We did not exclude any mechanism by which nutrients might have reached the marine system. Rather, we merely suggested dust as a possible carrier of iron, in light of the eolian hypothesis. We are raising questions and proposing hypotheses to consider. We do not know how significant dust may (or may not) have been in delivering nutrients (bioavailable iron) across Laurentian epeiric seas during the Late Devonian. Mechanisms of nutrient delivery are not mutually exclusive. In other words, sometimes the answer isn’t either/or, but both, or all the above.Finally, we disagree with Wilson and Schieber’s (2024) argument on the requirement for “a commensurate concentration of sand and formation of eolian dunes” to generate “copious quantities of dust.” As addressed in our paper, whilst much controversy surrounds the claim that sand dunes and eolian processes produce significant dust deposits, both empirical and experimental studies raise questions about the efficacy of sand saltation in producing silt, and this remains a contentious claim. For example, although sand saltation has been suggested for small loess accumulations such as the Negev in Israel (Crouvi et al. 2008), relatively minimal eolian silt (loess) occurs in the peri-Saharan region, for example (Smalley 1995)—where one might expect large volumes given the vast sand seas. Furthermore, recent experimental studies demonstrate the inefficiency of eolian saltation of sand for silt production (Swet et al. 2019, 2020; Adams and Soreghan 2020). Consider that the dustiest source on the planet today, the Bodélé Depression, is not sourced by dunes, but by the desiccated-lake deposits of paleolake Megachad (Warren et al. 2007). Similarly, dust off the Copper River Delta today is sourced by the deflation of glacially generated fines across (dried) floodplains, not sand dunes (Crusius et al. 2011).We again thank Wilson and Schieber for the opportunity for additional discussion, and for highlighting the need for further petrographic and SEM studies of the Woodford Shale focused specifically on the detrital component. It is likely we will continue to agree to disagree on several points; even so, we look forward to further testing and revision of our hypothesis that eolian-transported detrital silt and dust contributed to the Woodford Shale, and many of its correlatives.\",\"PeriodicalId\":17044,\"journal\":{\"name\":\"Journal of Sedimentary Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2024-02-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Sedimentary Research\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.2110/jsr.2023.122\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Sedimentary Research","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.2110/jsr.2023.122","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0

摘要

我们感谢 Wilson 和 Schieber 的讨论,因为我们在 Current Ripples 上发表的论文提出了一个新的假设,我们欢迎对该假设进行检验。McGlannan 等人(2022 年)通过对古地理学、古气候、粒度、锆英石来源、地球化学和地表风模型的整合,提出了风化迁移为北美大陆中部泥盆纪-密西西比海相地层提供了大量硅质碎屑材料的观点。Wilson 和 Schieber(2024 年)在讨论的开头说:"......将一个地层区间(早密西西比期)的推断沉积动力学推断到数百万年前(晚泥盆期)沉积的岩石上,既不值得推荐,也不被认为是好的做法。我们认为这种说法很奇怪,就像认为更新世的冰蚀沉积动力学不能适用于宾夕法尼亚时期的冰蚀沉积动力学一样。只要遵循过程统一性(统一论)的原则,过程可以跨时间应用。Wilson 和 Schieber(2024 年)随后集中提出了三个主要论点,以质疑我们的假说尤其是晚泥盆世假说的有效性。关于二氧化硅的自生或非晶体来源问题,我们认识到 Schieber 及其合作者在泥岩岩石学和岩石学方面拥有丰富的经验,我们了解并尊重他们记录泥岩中成岩二氧化硅的工作,事实上,我们在论文中也承认伍德福德页岩中普遍存在成岩二氧化硅和生物硅。例如,McGlannan 等人(2022 年)的图 5B 展示了伍德福德页岩中有节奏的、薄的、类似白垩岩的岩床。Wilson 和 Schieber 指出,他们研究了与我们研究地点相同的样本,发现了成岩硅石。我们对此并不怀疑。由于成岩硅石的普遍存在,我们优先避开了富含硅石的岩层,主要取样于层状页岩岩层。Wilson 和 Schieber(2024 年)认为我们 "在粉碎处理过程中 "产生了沙粒和淤泥大小的颗粒,但正如我们在论文中详细说明的那样,"用陶瓷研钵和研杵轻轻地将样本粉碎成豌豆大小的砾石,以加速化学反应,然后用蒸馏水冲洗,并用 250 μm 的筛子筛去粉碎过程中产生的细粒",这些细粒可能会被错误地纳入粒度分析中。在 19 个伍德福德页岩样本中,选择了 12 个样本进行粒度测量,然后进行涂片分析,以验证解离情况和是否存在大量的碎屑物质(补充文件 3 和 McGlannan 等人 2022 年的图 6A),这些碎屑物质不仅包括石英,还包括少量的长石,甚至还包括(罕见的)锆石等附属矿物。我们承认,尽管我们努力将成岩二氧化硅的含量降到最低,但仍可能残留一些微晶二氧化硅,这将使粒度结果偏向于更细的模式。此外,正如我们在论文中讨论的那样,富含二氧化硅的尘埃随风飘散,很可能为这些泥盆纪-密西西比时期单元中的生物硅石和成岩硅石提供了重要的硅源--这种解释建立在 Banks(1970 年)、Cecil(2015 年)和 Cecil 等人(2018 年)之前的研究基础之上。Wilson 和 Schieber(2024 年)随后论述了地层关系,暗示我们认为伍德福德页岩(以及相关的黑色页岩)应因半潜沉降而呈现出垂悬的几何形状,但我们无论如何都不会质疑底流运移对伍德福德页岩或其任何相关地层中的碎屑物质重新分布的影响。我们绝对承认海底再沉积和再分布的作用。我们在论文中多次提到,这些沉积物最终沉积在海洋环境中,但我们假设这些物质是通过风化作用进入海洋系统的。一旦风化尘进入表层水,就会受到海洋过程的影响,尤其是在海底斜坡上堆积的情况下。二叠纪特拉华山组的砂岩和粉砂岩等就属于类似的系统,其中海底物质流重新分配了风蚀搬运的细粒物质(Fischer 和 Sarnthein,1988 年)。在俄克拉荷马州,伍德福德页岩中肯定存在与基底面相对变化有关的地层复杂性,但要将这些复杂性与阿巴拉契亚前陆盆地以及地壳内伊利诺斯和密歇根盆地的复杂性进行比较,还需要进一步的地层研究。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
An eolian dust origin for clastic fines of Devono-Mississippian mudrocks of the greater North American midcontinent—Reply
We thank Wilson and Schieber for their discussion, as our paper in Current Ripples presented a new hypothesis, and we welcome tests of that hypothesis. Current Ripples encourages “provocative papers on sedimentary geology” so we are happy to motivate future research toward advancing knowledge on the Devono-Mississippian of North America.Through an integration of paleogeography, paleoclimate, grain size, detrital-zircon provenance, geochemistry, and surface-wind models, McGlannan et al. (2022) proposed that eolian transport supplied significant siliciclastic material to Devono-Mississippian marine strata of the North American midcontinent. Wilson and Schieber (2024) begin their discussion with the statement that “…extrapolating the inferred sedimentary dynamics of one stratigraphic interval (Early Mississippian) across a sequence boundary to rocks that were deposited multiple millions of years earlier (Late Devonian) is neither recommended nor considered good practice.” We find this odd, akin to arguing that, e.g., sediment dynamics of glacioeustasy in the Pleistocene cannot apply to glacioeustasy that operated in the Pennsylvanian. Processes can apply across time, as long as the tenets of uniformity of process (uniformitarianism) are followed. Wilson and Schieber (2024) then focus on three main arguments to challenge the validity of our hypothesis for the Late Devonian in particular.Regarding the issue of an authigenic or detrital origin for the silica, we recognize that Schieber and his collaborators have extensive experience with mudstone petrography and petrology, are aware of and respect their work documenting diagenetic silica in mudstones, and indeed acknowledge in our paper the pervasive presence of diagenetic and biogenic silica in the Woodford Shale. For example, Figure 5B in McGlannan et al. (2022) illustrates the rhythmic, thin, chert-like beds in the Woodford Shale. Wilson and Schieber note that they have studied samples from the same sites we studied and found diagenetic silica. We do not doubt this. Owing to the common presence of diagenetic silica, we preferentially avoided silica-rich facies and predominantly sampled laminated shale facies. Wilson and Schieber (2024) suggest that we generated sand- and silt-size particles “upon crushing–processing” but, as we detailed in our paper, “Samples were gently crushed with a ceramic mortar and pestle to pea-size gravel to accelerate chemical reactions, then rinsed with distilled water and sieved at 250 μm to remove any fines generated during crushing” that might be erroneously incorporated in the grain-size analyses. Of 19 Woodford Shale samples, 12 were selected for particle-size measurement after smear-slide analysis to verify disaggregation and presence of a preponderance of detrital material (Supplemental File 3 and Fig. 6A in McGlannan et al. 2022), which included not only quartz, but minor feldspar and even (rare) accessory minerals such as zircon. We acknowledge that, despite our efforts to minimize the inclusion of diagenetic silica, some microcrystallized silica may have remained, which would have skewed particle-size results to finer modes. Additionally, as discussed in our paper, eolian delivery of silica-rich dust likely provided a significant source of Si for biogenic and diagenetic silica in these Devono-Mississippian units—an interpretation that builds on previous work by others, such as Banks (1970), Cecil (2015), and Cecil et al. (2018).Wilson and Schieber (2024) then address stratigraphic relationships, implying that we believe the Woodford (and correlative black shales) should exhibit a draping geometry owing to hemipelagic settling, but we do not, in any way, dispute a component of bottom-current transport for the redistribution of detrital material in the Woodford Shale or any of its correlative formations. We absolutely acknowledge the action of submarine redeposition and redistribution. We mention several times throughout the paper that these sediments were ultimately deposited in the marine environment, but we hypothesize eolian delivery of the material to the marine system. Once eolian dust hits the surface waters, it is subject to marine processes, especially if accumulation occurs on submarine slopes. Analogous systems wherein submarine mass flows redistributed eolian-transported fines include the sandstones and siltstones of the Permian Delaware Mountain Group, for example (Fischer and Sarnthein 1988).We do not doubt the existence of stratigraphic complexities related to basin dynamics and sea-level fluctuations. Stratigraphic complexities in the Woodford Shale related to relative changes in base level are certainly present in Oklahoma, but the comparison of these complexities to those in the Appalachian foreland basin and the intracratonic Illinois and Michigan basins requires much further stratigraphic study. During the Late Devonian the Anadarko basin was essentially a wide passive margin facing southward into the Rheic Sea. Although there appears to be an intra-Woodford unconformity at the Devonian–Carboniferous boundary, the continuity in conodont and pollen biozones at the I-35 South outcrop in Oklahoma (Over 1990, 1992; Kondas et al. 2018) and conodont zones at the Wapanucka (Over 1990), and Hass G (Boardman and Puckette 2006; Haywa-Branch and Barrick 1990; Over and Barrick 1990) locations demonstrate that the Upper Woodford unconformity is of a lower magnitude than certain regions in the up-dip interior Illinois basin (Over et al. 2019; Over 2021; Fig. 6 in Lazar and Schieber 2022). Yet, the sediments are similar; therefore eolian delivery provides a viable means for transporting sediments beyond the Appalachian system.In their third major point, Wilson and Schieber (2024) take issue with the hypothesis of eolian nutrient fertilization. Regarding nutrients supplied to Devonian epeiric seas, we accept the possibility of eutrophication from the expansion of terrestrial land plants, and deep basin upwelling, in addition to eolian dust fertilization. We did not exclude any mechanism by which nutrients might have reached the marine system. Rather, we merely suggested dust as a possible carrier of iron, in light of the eolian hypothesis. We are raising questions and proposing hypotheses to consider. We do not know how significant dust may (or may not) have been in delivering nutrients (bioavailable iron) across Laurentian epeiric seas during the Late Devonian. Mechanisms of nutrient delivery are not mutually exclusive. In other words, sometimes the answer isn’t either/or, but both, or all the above.Finally, we disagree with Wilson and Schieber’s (2024) argument on the requirement for “a commensurate concentration of sand and formation of eolian dunes” to generate “copious quantities of dust.” As addressed in our paper, whilst much controversy surrounds the claim that sand dunes and eolian processes produce significant dust deposits, both empirical and experimental studies raise questions about the efficacy of sand saltation in producing silt, and this remains a contentious claim. For example, although sand saltation has been suggested for small loess accumulations such as the Negev in Israel (Crouvi et al. 2008), relatively minimal eolian silt (loess) occurs in the peri-Saharan region, for example (Smalley 1995)—where one might expect large volumes given the vast sand seas. Furthermore, recent experimental studies demonstrate the inefficiency of eolian saltation of sand for silt production (Swet et al. 2019, 2020; Adams and Soreghan 2020). Consider that the dustiest source on the planet today, the Bodélé Depression, is not sourced by dunes, but by the desiccated-lake deposits of paleolake Megachad (Warren et al. 2007). Similarly, dust off the Copper River Delta today is sourced by the deflation of glacially generated fines across (dried) floodplains, not sand dunes (Crusius et al. 2011).We again thank Wilson and Schieber for the opportunity for additional discussion, and for highlighting the need for further petrographic and SEM studies of the Woodford Shale focused specifically on the detrital component. It is likely we will continue to agree to disagree on several points; even so, we look forward to further testing and revision of our hypothesis that eolian-transported detrital silt and dust contributed to the Woodford Shale, and many of its correlatives.
求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
CiteScore
3.80
自引率
5.00%
发文量
50
审稿时长
3 months
期刊介绍: The journal is broad and international in scope and welcomes contributions that further the fundamental understanding of sedimentary processes, the origin of sedimentary deposits, the workings of sedimentary systems, and the records of earth history contained within sedimentary rocks.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信