H. Lorenz, Jan-Erik Rosberg, C. Juhlin, I. Klonowska, R. Lescoutre, G. Westmeijer, B. Almqvist, M. Anderson, S. Bertilsson, M. Dopson, J. Kallmeyer, J. Kück, O. Lehnert, L. Menegon, C. Pascal, S. Rejkjær, Nick N. W. Roberts
Abstract. The Collisional Orogeny in the Scandinavian Caledonides (COSC) scientific drilling project aims to characterise the structure and orogenic processes involved in a major collisional mountain belt by multidisciplinary geoscientific research. Located in western central Sweden, the project has drilled two fully cored deep boreholes into the bedrock of the deeply eroded Early Paleozoic Caledonide Orogen. COSC-1 (2014) drilled a subduction-related allochthon and the associated thrust zone. COSC-2 (2020, this paper) extends this section deeper through the underlying nappes (Lower Allochthon), the main Caledonian décollement, and the upper kilometre of basement rocks. COSC-2 targets include the characterisation of orogen-scale detachments, the impact of orogenesis on the basement below the detachment, and the Early Paleozoic palaeoenvironment on the outer margin of palaeocontinent Baltica. This is complemented by research on heat flow, groundwater flow, and the characterisation of the microbial community in the present hard rock environment of the relict mountain belt. COSC-2 successfully, and within budget, recovered a continuous drill core to 2276 m depth. The retrieved geological section is partially different from the expected geological section with respect to the depth to the main décollement and the expected rock types. Although the intensity of synsedimentary deformation in the rocks in the upper part of the drill core might impede the analysis of the Early Paleozoic palaeoenvironment, the superb quality of the drill core and the borehole will facilitate research on the remaining targets and beyond. Protocols for sampling in the hard rock environment and subsequent sample preservation were established for geomicrobiological research and rock mechanical testing. For the former, a sparse sample series along the entire drill core was taken, while the target of the latter was the décollement. COSC-2 was surveyed by a comprehensive post-drilling downhole logging campaign and a combined borehole/land seismic survey in autumn 2021. This paper provides an overview of the COSC-2 (International Continental Scientific Drilling Project – ICDP 5054_2_A and 5054_2_B boreholes) operations and preliminary results. It will be complemented by a detailed operational report and data publication.
{"title":"COSC-2 – drilling the basal décollement and underlying margin of palaeocontinent Baltica in the Paleozoic Caledonide Orogen of Scandinavia","authors":"H. Lorenz, Jan-Erik Rosberg, C. Juhlin, I. Klonowska, R. Lescoutre, G. Westmeijer, B. Almqvist, M. Anderson, S. Bertilsson, M. Dopson, J. Kallmeyer, J. Kück, O. Lehnert, L. Menegon, C. Pascal, S. Rejkjær, Nick N. W. Roberts","doi":"10.5194/sd-30-43-2022","DOIUrl":"https://doi.org/10.5194/sd-30-43-2022","url":null,"abstract":"Abstract. The Collisional Orogeny in the Scandinavian Caledonides (COSC) scientific\u0000drilling project aims to characterise the structure and orogenic processes\u0000involved in a major collisional mountain belt by multidisciplinary geoscientific research. Located in western central Sweden, the project has\u0000drilled two fully cored deep boreholes into the bedrock of the deeply eroded Early Paleozoic Caledonide Orogen. COSC-1 (2014) drilled a\u0000subduction-related allochthon and the associated thrust zone. COSC-2 (2020,\u0000this paper) extends this section deeper through the underlying nappes (Lower Allochthon), the main Caledonian décollement, and the upper kilometre of basement rocks. COSC-2 targets include the characterisation of orogen-scale detachments, the impact of orogenesis on the basement below the detachment, and the Early Paleozoic palaeoenvironment on the outer margin of palaeocontinent Baltica. This is complemented by research on heat flow, groundwater flow, and the characterisation of the microbial community in the present hard rock environment of the relict mountain belt. COSC-2\u0000successfully, and within budget, recovered a continuous drill core to 2276 m depth. The retrieved geological section is partially different from the expected geological section with respect to the depth to the main\u0000décollement and the expected rock types. Although the intensity of synsedimentary deformation in the rocks in the upper part of the drill core might impede\u0000the analysis of the Early Paleozoic palaeoenvironment, the superb quality of\u0000the drill core and the borehole will facilitate research on the remaining\u0000targets and beyond. Protocols for sampling in the hard rock environment and\u0000subsequent sample preservation were established for geomicrobiological\u0000research and rock mechanical testing. For the former, a sparse sample series along the entire drill core was taken, while the target of the latter was the décollement. COSC-2 was surveyed by a comprehensive post-drilling downhole logging campaign and a combined borehole/land seismic survey in autumn 2021. This paper provides an overview of the COSC-2 (International Continental Scientific Drilling Project – ICDP 5054_2_A and 5054_2_B boreholes) operations and preliminary results. It will be complemented by a detailed operational report and data publication.\u0000","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"13 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72654696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Umino, G. Moore, B. Boston, R. Coggon, L. Crispini, S. D’Hondt, Michael O. Garcia, T. Hanyu, F. Klein, N. Seama, D. Teagle, M. Tominaga, M. Yamashita, M. Harris, B. Ildefonse, I. Katayama, Y. Kusano, Yohey Suzuki, E. Trembath-Reichert, Yasuhiro Yamada, N. Abe, Nan Xiao, F. Inagaki
Abstract. For more than half a century, exploring a complete sequence of the oceanic crust from the seafloor through the Mohorovičić discontinuity (Moho) and into the uppermost mantle has been one of the most challenging missions of scientific ocean drilling. Such a scientific and technological achievement would provide humankind with profound insights into the largest realm of our planet and expand our fundamental understanding of Earth's deep interior and its geodynamic behavior. The formation of new oceanic crust at mid-ocean ridges and its subsequent aging over millions of years, leading to subduction, arc volcanism, and recycling of some components into the mantle, comprise the dominant geological cycle of matter and energy on Earth. Although previous scientific ocean drilling has cored some drill holes into old (> 110 Ma) and young (< 20 Ma) ocean crust, our sampling remains relatively shallow (< 2 km into intact crust) and unrepresentative of average oceanic crust. To date, no hole penetrates more than 100 m into intact average-aged oceanic crust that records the long-term history of seawater–basalt exchange (60 to 90 Myr). In addition, the nature, extent, and evolution of the deep subseafloor biosphere within oceanic crust remains poorly unknown. To address these fundamentally significant scientific issues, an international workshop “Exploring Deep Oceanic Crust off Hawai`i” brought together 106 scientists and engineers from 16 countries that represented the entire spectrum of disciplines, including petrologists, geophysicists, geochemists, microbiologists, geodynamic modelers, and drilling/logging engineers. The aim of the workshop was to develop a full International Ocean Discovery Program (IODP) proposal to drill a 2.5 km deep hole into oceanic crust on the North Arch off Hawai`i with the drilling research vessel Chikyu. This drill hole would provide samples down to cumulate gabbros of mature (∼ 80 Ma) oceanic crust formed at a half spreading rate of ∼ 3.5 cm a−1. A Moho reflection has been observed at ∼ 5.5 km below the seafloor at this site, and the workshop concluded that the proposed 2.5 km deep scientific drilling on the North Arch off Hawai`i would provide an essential “pilot hole” to inform the design of future mantle drilling.
{"title":"Workshop report: Exploring deep oceanic crust off Hawai`i","authors":"S. Umino, G. Moore, B. Boston, R. Coggon, L. Crispini, S. D’Hondt, Michael O. Garcia, T. Hanyu, F. Klein, N. Seama, D. Teagle, M. Tominaga, M. Yamashita, M. Harris, B. Ildefonse, I. Katayama, Y. Kusano, Yohey Suzuki, E. Trembath-Reichert, Yasuhiro Yamada, N. Abe, Nan Xiao, F. Inagaki","doi":"10.5194/SD-29-69-2021","DOIUrl":"https://doi.org/10.5194/SD-29-69-2021","url":null,"abstract":"Abstract. For more than half a century, exploring a complete sequence of the oceanic\u0000crust from the seafloor through the Mohorovičić discontinuity (Moho)\u0000and into the uppermost mantle has been one of the most challenging missions\u0000of scientific ocean drilling. Such a scientific and technological\u0000achievement would provide humankind with profound insights into the largest\u0000realm of our planet and expand our fundamental understanding of Earth's deep\u0000interior and its geodynamic behavior. The formation of new oceanic crust at\u0000mid-ocean ridges and its subsequent aging over millions of years, leading to\u0000subduction, arc volcanism, and recycling of some components into the mantle,\u0000comprise the dominant geological cycle of matter and energy on Earth.\u0000Although previous scientific ocean drilling has cored some drill holes into\u0000old (> 110 Ma) and young (< 20 Ma) ocean crust, our\u0000sampling remains relatively shallow (< 2 km into intact crust) and\u0000unrepresentative of average oceanic crust. To date, no hole penetrates more\u0000than 100 m into intact average-aged oceanic crust that records the long-term\u0000history of seawater–basalt exchange (60 to 90 Myr). In addition,\u0000the nature, extent, and evolution of the deep subseafloor biosphere within\u0000oceanic crust remains poorly unknown. To address these fundamentally\u0000significant scientific issues, an international workshop “Exploring Deep\u0000Oceanic Crust off Hawai`i” brought together 106 scientists and engineers\u0000from 16 countries that represented the entire spectrum of disciplines, including\u0000petrologists, geophysicists, geochemists, microbiologists, geodynamic\u0000modelers, and drilling/logging engineers. The aim of the workshop was to\u0000develop a full International Ocean Discovery Program (IODP) proposal to\u0000drill a 2.5 km deep hole into\u0000oceanic crust on the North Arch off Hawai`i with the drilling research vessel Chikyu. This drill hole would provide\u0000samples down to cumulate gabbros of mature (∼ 80 Ma) oceanic\u0000crust formed at a half spreading rate of ∼ 3.5 cm a−1. A Moho\u0000reflection has been observed at ∼ 5.5 km below the seafloor at\u0000this site, and the workshop concluded that the proposed 2.5 km deep\u0000scientific drilling on the North Arch off Hawai`i would provide an essential\u0000“pilot hole” to inform the design of future mantle drilling.\u0000","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"26 1","pages":"69-82"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86904857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. L. Pendleton, K. I. Twing, S. Motamedi, W. Brazelton
Abstract. International Ocean Discovery Program (IODP) Expedition 357: “Serpentinization and Life” drilled shallow cores into the Atlantis Massif near the Mid-Atlantic Ridge in October 2015 using seabed drills. Serpentinization and other geochemical processes occurring within the Atlantis Massif release hydrogen, methane, and other chemicals that can potentially fuel microorganisms through chemosynthesis. The subseafloor rock cores collected during IODP Exp. 357 are the first of their kind, meaning the analysis and interpretation of these samples required new methodologies, including a specialized approach for distinguishing endemic subsurface inhabitants from potential contaminants from various sources. Background samples of various potential contamination sources were collected during sampling: 109 samples of seawater collected before, during, and after drilling; 20 samples of greases and oils associated with the drilling equipment; and samples of the laboratory's ambient air. Despite the widespread usage of drilling lubricants and the importance of controlling contamination in drill-core samples for microbiological analyses, no studies to date have looked at DNA in drilling greases and oils. In this study, drilling lubricants were analyzed as possible sources of microbial contamination of subseafloor rock core samples by environmental sequencing of 16S rRNA genes. We find that microbial signatures from drilling lubricants are only found in low abundance in seafloor samples (at most a few percent of total sequence counts), with laboratory contaminants being a greater source of contamination.
{"title":"Potential microbial contamination from drilling lubricants into subseafloor rock cores","authors":"H. L. Pendleton, K. I. Twing, S. Motamedi, W. Brazelton","doi":"10.5194/SD-29-49-2021","DOIUrl":"https://doi.org/10.5194/SD-29-49-2021","url":null,"abstract":"Abstract. International Ocean Discovery Program (IODP) Expedition 357: “Serpentinization and Life” drilled shallow cores into the Atlantis\u0000Massif near the Mid-Atlantic Ridge in October 2015 using seabed drills. Serpentinization and other geochemical processes occurring within the\u0000Atlantis Massif release hydrogen, methane, and other chemicals that can\u0000potentially fuel microorganisms through chemosynthesis. The subseafloor rock\u0000cores collected during IODP Exp. 357 are the first of their kind, meaning\u0000the analysis and interpretation of these samples required new methodologies,\u0000including a specialized approach for distinguishing endemic subsurface\u0000inhabitants from potential contaminants from various sources. Background\u0000samples of various potential contamination sources were collected during\u0000sampling: 109 samples of seawater collected before, during, and after\u0000drilling; 20 samples of greases and oils associated with the drilling\u0000equipment; and samples of the laboratory's ambient air. Despite the\u0000widespread usage of drilling lubricants and the importance of controlling\u0000contamination in drill-core samples for microbiological analyses, no studies\u0000to date have looked at DNA in drilling greases and oils. In this study,\u0000drilling lubricants were analyzed as possible sources of microbial\u0000contamination of subseafloor rock core samples by environmental sequencing\u0000of 16S rRNA genes. We find that microbial signatures from drilling\u0000lubricants are only found in low abundance in seafloor samples (at most a\u0000few percent of total sequence counts), with laboratory contaminants being a\u0000greater source of contamination.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"111 1","pages":"49-57"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84766853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Seol, L. Lei, K. Jarvis, D. Hill, Jeong-Hoon Choi, T. Park, X. Gai, Greg Wunderlich, Bill Grey, Chris McArdle
Abstract. The pore habits of gas hydrate in natural sediment matrices provide essential clues for understanding physical (mechanical, thermal, hydraulic, and electrical) properties of hydrate-bearing sediments, yet there are no tools that can directly visualize the pore habits of natural gas hydrate other than indirect interpretation based on core-scale or field-scale observations. A significant challenge is to obtain a mini-core from pressure cores retrieved from natural reservoirs for high-resolution micro-CT (computed tomography) scans while maintaining pressure and temperature conditions required for stability of gas hydrate during all operational steps including manipulation, cutting, transferring, sub-coring and CT scanning. We present a new set of tools for pore-scale micro-CT imaging of natural hydrate-bearing sediments while maintaining pressure and temperature control. The tests with laboratory-prepared cores and pressure cores successfully demonstrate the capability of this set of tools to subsample a mini-core from pressure cores, transfer the mini-core to an X-ray transparent core holder, and conduct micro-CT scans. Successfully obtained CT images prove the functionality of this set of tools.
{"title":"Tools for pressure core sub-coring and pore-scale micro-CT (computed tomography) scans","authors":"Y. Seol, L. Lei, K. Jarvis, D. Hill, Jeong-Hoon Choi, T. Park, X. Gai, Greg Wunderlich, Bill Grey, Chris McArdle","doi":"10.5194/SD-29-59-2021","DOIUrl":"https://doi.org/10.5194/SD-29-59-2021","url":null,"abstract":"Abstract. The pore habits of gas hydrate in natural sediment\u0000matrices provide essential clues for understanding physical (mechanical,\u0000thermal, hydraulic, and electrical) properties of hydrate-bearing sediments,\u0000yet there are no tools that can directly visualize the pore habits of\u0000natural gas hydrate other than indirect interpretation based on core-scale\u0000or field-scale observations. A significant challenge is to obtain a\u0000mini-core from pressure cores retrieved from natural reservoirs for\u0000high-resolution micro-CT (computed tomography) scans while maintaining pressure and temperature conditions required for stability of gas hydrate\u0000during all operational steps including manipulation, cutting, transferring,\u0000sub-coring and CT scanning. We present a new set of tools for pore-scale micro-CT imaging of natural hydrate-bearing sediments while maintaining\u0000pressure and temperature control. The tests with laboratory-prepared cores and pressure cores successfully demonstrate the capability of this set of\u0000tools to subsample a mini-core from pressure cores, transfer the mini-core\u0000to an X-ray transparent core holder, and conduct micro-CT scans.\u0000Successfully obtained CT images prove the functionality of this set of\u0000tools.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"286 23 1","pages":"59-67"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85181833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Fauth, M. D. Bruno, Jorge Villegas‐Martín, J. Savian, R. M. Guerra, Guilherme Krahl, F. O. L. Lima, Oscar Strohschoen Jr., Raquel Gewehr de Mello, Fernando M. Lopes, C. G. Leandro, Eduardo Aguiar
Abstract. The Aptian–Albian interval is characterized by significant paleoclimatic, paleoceanographic, and paleogeographic changes, which in turn affected the distribution and evolution of marine ecosystems. Despite the importance of such studies, there have been few correlations between Aptian–Albian sections of the Tethys Sea and those of the South Atlantic Ocean. This interval, including the Aptian–Albian transition, is preserved in the deposits of the Riachuelo Formation (Sergipe–Alagoas Basin, Brazil) located in the South Atlantic Ocean; therefore, this location was chosen for drilling four new cores. The goals of this paper are as follows: (1) to explain the drilling operation carried out in the deposits of the Riachuelo Formation and the methods used; (2) to present a brief lithostratigraphic characterization of the holes and the paleomagnetic data of core SER-03; and (3) to describe the high potential of the cores recovered for additional investigation in the future. The lithostratigraphic units of the SER-01 core consist mainly of coarse- to fine-grained sandstone, shales, marls, and mudstones; the SER-02 core was excluded due to low recovery; the SER-03 core is mainly composed of fine-grained sediments (shale, marls, and packstone) and bears some ammonite shells; the lithology of core SER-04 is mainly sandstones. Magnetic susceptibility values ( χ lf and χ hf) and frequency-dependent susceptibility ( χ fd) data suggest that the section is located within the Cretaceous Normal Superchron. Future studies on these cores integrating micropaleontological, paleoichnological, geochemical, stratigraphic, and paleomagnetic (e.g., relative intensity) data will allow for a better understanding of paleoceanographic and paleogeographic events related to the early evolution of the South Atlantic Ocean and how these events correlate to similar events in Tethyan sections.
{"title":"Drilling the Aptian–Albian of the Sergipe–Alagoas Basin, Brazil: paleobiogeographic and paleoceanographic studies in the South Atlantic","authors":"G. Fauth, M. D. Bruno, Jorge Villegas‐Martín, J. Savian, R. M. Guerra, Guilherme Krahl, F. O. L. Lima, Oscar Strohschoen Jr., Raquel Gewehr de Mello, Fernando M. Lopes, C. G. Leandro, Eduardo Aguiar","doi":"10.5194/SD-29-1-2021","DOIUrl":"https://doi.org/10.5194/SD-29-1-2021","url":null,"abstract":"Abstract. The Aptian–Albian interval is characterized by significant\u0000paleoclimatic, paleoceanographic, and paleogeographic changes, which in turn\u0000affected the distribution and evolution of marine ecosystems. Despite the\u0000importance of such studies, there have been few correlations between\u0000Aptian–Albian sections of the Tethys Sea and those of the South Atlantic\u0000Ocean. This interval, including the Aptian–Albian transition, is preserved\u0000in the deposits of the Riachuelo Formation (Sergipe–Alagoas Basin, Brazil)\u0000located in the South Atlantic Ocean; therefore, this location was chosen for drilling\u0000four new cores. The goals of this paper are as follows: (1) to explain the drilling\u0000operation carried out in the deposits of the Riachuelo Formation and the\u0000methods used; (2) to present a brief lithostratigraphic characterization of\u0000the holes and the paleomagnetic data of core SER-03; and (3) to describe\u0000the high potential of the cores recovered for additional investigation in the\u0000future. The lithostratigraphic units of the SER-01 core consist mainly of\u0000coarse- to fine-grained sandstone, shales, marls, and mudstones; the SER-02\u0000core was excluded due to low recovery; the SER-03 core is mainly composed\u0000of fine-grained sediments (shale, marls, and packstone) and bears some\u0000ammonite shells; the lithology of core SER-04 is mainly sandstones.\u0000Magnetic susceptibility values ( χ lf and χ hf) and\u0000frequency-dependent susceptibility ( χ fd) data suggest that the section\u0000is located within the Cretaceous Normal Superchron. Future studies on these\u0000cores integrating micropaleontological, paleoichnological, geochemical,\u0000stratigraphic, and paleomagnetic (e.g., relative intensity) data will allow\u0000for a better understanding of paleoceanographic and paleogeographic events\u0000related to the early evolution of the South Atlantic Ocean and how these\u0000events correlate to similar events in Tethyan sections.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"17 1","pages":"1-17"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87854431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Benjamin Läuchli, P. Augustinus, Leonie Peti, J. Hopkins
Abstract. The accurate and precise reconstruction of Quaternary climate as well as the events that punctuate it is an important driver of the study of lake sediment archives. However, until recently lake sediment-based palaeoclimate reconstructions have largely concentrated on Northern Hemisphere lake sequences due to a scarcity of continuous and high-resolution lake sediment sequences from the Southern Hemisphere, especially from the southern mid-latitudes. In this context, the deep maar lakes of the Auckland Volcanic Field of northern New Zealand are significant as several contain continuous and well-laminated sediment sequences. Onepoto Basin potentially contains the longest temporal lake sediment record from the Auckland Volcanic Field (AVF), spanning from Marine Isotope Stage 6e (MIS 6e) to the early Holocene when lacustrine sedimentation was terminated by marine breach of the south-western crater tuff ring associated with post-glacial sea-level rise. The Onepoto record consists of two new, overlapping cores spanning ca. 73 m combined with archive material in a complete composite stratigraphy. Tephrochronology and 14 C dating provide the fundamental chronological framework for the core, with magnetic relative palaeo-intensity variability downcore, and meteoric 10 Be influx into the palaeolake to refine the chronology. The µ -XRF (micro X-ray fluorescence) downcore variability for the entirety of the lake sediment sequence has been established with measurement of a range of proxies for climate currently underway. This work will produce the first continuous record of the last 200 kyr of palaeoclimate from northern New Zealand to date.
摘要第四纪气候的精确重建及其间断事件是湖泊沉积物档案研究的重要推动力。然而，直到最近，基于湖泊沉积物的古气候重建主要集中在北半球的湖泊序列上，因为缺乏来自南半球，特别是来自中纬度南部的连续和高分辨率湖泊沉积物序列。在这种背景下，新西兰北部奥克兰火山场的深马尔湖具有重要意义，因为其中一些湖含有连续且层状良好的沉积层序。OnepotoBasin可能包含奥克兰火山场(AVF)以来最长的湖泊沉积记录，从海洋同位素阶段6e (MIS 6e)跨越到全新世早期，在全新世早期，湖泊沉积被西南火山口凝灰岩环的海蚀口终止，并与冰川后海平面上升有关。Onepoto记录由两个新的重叠岩心组成，跨度约73米，并结合了完整复合地层中的档案材料。温度年代学和14c测年为岩心提供了基本的年代学框架，岩心下部的磁相对古强度变率和流入古湖的大气10 - Be为年代学提供了完善的依据。通过测量当前正在进行的一系列气候代用物，建立了整个湖泊沉积物序列的µ-XRF(微x射线荧光)下核变异性。这项工作将产生迄今为止新西兰北部近200年古气候的第一个连续记录。
{"title":"Composite development and stratigraphy of the Onepoto maar lake sediment sequence (Auckland Volcanic Field, New Zealand)","authors":"Benjamin Läuchli, P. Augustinus, Leonie Peti, J. Hopkins","doi":"10.5194/SD-29-19-2021","DOIUrl":"https://doi.org/10.5194/SD-29-19-2021","url":null,"abstract":"Abstract. The accurate and precise reconstruction of Quaternary\u0000climate as well as the events that punctuate it is an important driver of the study\u0000of lake sediment archives. However, until recently lake sediment-based\u0000palaeoclimate reconstructions have largely concentrated on Northern\u0000Hemisphere lake sequences due to a scarcity of continuous and\u0000high-resolution lake sediment sequences from the Southern Hemisphere,\u0000especially from the southern mid-latitudes. In this context, the deep maar\u0000lakes of the Auckland Volcanic Field of northern New Zealand are significant\u0000as several contain continuous and well-laminated sediment sequences. Onepoto\u0000Basin potentially contains the longest temporal lake sediment record from\u0000the Auckland Volcanic Field (AVF), spanning from Marine Isotope Stage 6e (MIS 6e) to the early Holocene when lacustrine\u0000sedimentation was terminated by marine breach of the south-western crater\u0000tuff ring associated with post-glacial sea-level rise. The Onepoto record\u0000consists of two new, overlapping cores spanning ca. 73 m combined with\u0000archive material in a complete composite stratigraphy. Tephrochronology and\u0000 14 C dating provide the fundamental chronological framework for the core,\u0000with magnetic relative palaeo-intensity variability downcore, and meteoric\u0000 10 Be influx into the palaeolake to refine the chronology. The µ -XRF (micro X-ray fluorescence)\u0000downcore variability for the entirety of the lake sediment sequence has\u0000been established with measurement of a range of proxies for climate\u0000currently underway. This work will produce the first continuous record of\u0000the last 200 kyr of palaeoclimate from northern New Zealand to date.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"65 1","pages":"19-37"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84483179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Kück, Marco Groh, Martin Töpfer, A. Jurczyk, U. Harms
Abstract. We established a cable-free memory-logging system for drill-string-deployed geophysical borehole measurements. For more than 20 years, various so-called “logging while tripping” (LWT) techniques have been available in the logging service industry. However, this method has rarely been used in scientific drilling, although it enables logging in deviated and unstable boreholes, such as in lacustrine sediment drilling projects. LWT operations have a far lower risk of damage or loss of downhole logging equipment compared with the common wireline logging. For this purpose, we developed, tested, and commissioned a modular memory-logging system that does not require drill string modifications, such as special collars, and can be deployed in standard wireline core drilling diameters (HQ, bit size of 96 mm, and PQ, bit size of 123 mm). The battery-powered, autonomous sondes register the profiles of the natural GR (gamma radiation) spectrum, sonic velocity, magnetic susceptibility, electric resistivity, temperature, and borehole inclination in high quality while they are pulled out along with the drill string. As a precise depth measurement carried out in the drill rig is just as important as the actual petrophysical downhole measurements, we developed depth-measuring devices providing a high accuracy of less than 0.1 m deviation from the wireline-determined depth. Moreover, the modular structure of the system facilitates sonde deployment in online mode for wireline measurements.
摘要我们建立了一套无电缆记忆测井系统，用于钻柱部署的地球物理井眼测量。20多年来，在测井服务行业中出现了各种所谓的“随起下钻测井”(LWT)技术。然而，这种方法很少用于科学钻井，尽管它可以在斜度和不稳定的井眼中进行测井，例如在湖泊沉积物钻井项目中。与普通电缆测井相比，LWT作业的井下测井设备损坏或丢失的风险要低得多。为此，我们开发、测试并调试了一种模块化记忆测井系统，该系统不需要修改钻柱，例如特殊的钻铤，并且可以在标准电缆岩心钻井直径(HQ，钻头尺寸为96 mm, PQ，钻头尺寸为123 mm)中部署。当随钻柱一起被取出时，电池供电的自主探空仪可以高质量地记录自然GR(伽马辐射)谱、声速、磁化率、电阻率、温度和井眼倾角的剖面。由于在钻机上进行的精确深度测量与实际的井下岩石物理测量同样重要，因此我们开发了深度测量设备，其精度与电缆测量深度的偏差小于0.1 m。此外，该系统的模块化结构便于在在线模式下部署探空仪进行有线测量。
{"title":"New geophysical memory-logging system for highly unstable and inclined scientific exploration drilling","authors":"J. Kück, Marco Groh, Martin Töpfer, A. Jurczyk, U. Harms","doi":"10.5194/SD-29-39-2021","DOIUrl":"https://doi.org/10.5194/SD-29-39-2021","url":null,"abstract":"Abstract. We established a cable-free memory-logging system for drill-string-deployed geophysical borehole measurements. For more than 20 years,\u0000various so-called “logging while tripping” (LWT) techniques have been available in\u0000the logging service industry. However, this method has rarely been used in\u0000scientific drilling, although it enables logging in deviated and unstable\u0000boreholes, such as in lacustrine sediment drilling projects. LWT operations\u0000have a far lower risk of damage or loss of downhole logging equipment compared with\u0000the common wireline logging. For this\u0000purpose, we developed, tested, and commissioned a modular memory-logging system that does not require drill string\u0000modifications, such as special collars, and can be deployed in standard\u0000wireline core drilling diameters (HQ, bit size of 96 mm, and PQ, bit size of 123 mm). The battery-powered, autonomous\u0000sondes register the profiles of the natural GR (gamma radiation) spectrum, sonic\u0000velocity, magnetic susceptibility, electric resistivity, temperature, and\u0000borehole inclination in high quality while they are pulled out along with the drill\u0000string. As a precise depth measurement carried out in the drill rig is\u0000just as important as the actual petrophysical downhole measurements, we\u0000developed depth-measuring devices providing a high accuracy of less than 0.1 m deviation from the wireline-determined depth. Moreover, the modular structure of\u0000the system facilitates sonde deployment in online mode for wireline\u0000measurements.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"35 1","pages":"39-48"},"PeriodicalIF":1.2,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85127385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David R. Cox, P. Knutz, D. Campbell, J. Hopper, A. Newton, M. Huuse, K. Gohl
Abstract. A geohazard assessment workflow is presented that maximizes the use of 3D seismic reflection data to improve the safety and success of offshore scientific drilling. This workflow has been implemented for International Ocean Discovery Program (IODP) Proposal 909 that aims to core seven sites with targets between 300 and 1000 m below seabed across the north-western Greenland continental shelf. This glaciated margin is a frontier petroleum province containing potential drilling hazards that must be avoided during drilling. Modern seismic interpretation techniques are used to identify, map and spatially analyse seismic features that may represent subsurface drilling hazards, such as seabed structures, faults, fluids and challenging lithologies. These hazards are compared against the spatial distribution of stratigraphic targets to guide site selection and minimize risk. The 3D seismic geohazard assessment specifically advanced the proposal by providing a more detailed and spatially extensive understanding of hazard distribution that was used to confidently select eight new site locations, abandon four others and fine-tune sites originally selected using 2D seismic data. Had several of the more challenging areas targeted by this proposal only been covered by 2D seismic data, it is likely that they would have been abandoned, restricting access to stratigraphic targets. The results informed the targeted location of an ultra-high-resolution 2D seismic survey by minimizing acquisition in unnecessary areas, saving valuable resources. With future IODP missions targeting similarly challenging frontier environments where 3D seismic data are available, this workflow provides a template for geohazard assessments that will enhance the success of future scientific drilling.
{"title":"Geohazard detection using 3D seismic data to enhance offshore scientific drilling site selection","authors":"David R. Cox, P. Knutz, D. Campbell, J. Hopper, A. Newton, M. Huuse, K. Gohl","doi":"10.5194/sd-28-1-2020","DOIUrl":"https://doi.org/10.5194/sd-28-1-2020","url":null,"abstract":"Abstract. A geohazard assessment workflow is presented that maximizes the use of 3D seismic reflection data to improve the safety and success of offshore\u0000scientific drilling. This workflow has been implemented for International\u0000Ocean Discovery Program (IODP) Proposal 909 that aims to core seven sites\u0000with targets between 300 and 1000 m below seabed across the north-western Greenland continental shelf. This glaciated margin is a frontier petroleum province containing potential drilling hazards that must be avoided during drilling.\u0000Modern seismic interpretation techniques are used to identify, map and\u0000spatially analyse seismic features that may represent subsurface drilling\u0000hazards, such as seabed structures, faults, fluids and challenging\u0000lithologies. These hazards are compared against the spatial distribution of\u0000stratigraphic targets to guide site selection and minimize risk. The 3D\u0000seismic geohazard assessment specifically advanced the proposal by providing\u0000a more detailed and spatially extensive understanding of hazard distribution\u0000that was used to confidently select eight new site locations, abandon four others and fine-tune sites originally selected using 2D seismic data. Had several\u0000of the more challenging areas targeted by this proposal only been covered by\u00002D seismic data, it is likely that they would have been abandoned,\u0000restricting access to stratigraphic targets. The results informed the\u0000targeted location of an ultra-high-resolution 2D seismic survey by\u0000minimizing acquisition in unnecessary areas, saving valuable resources. With future IODP missions targeting similarly challenging frontier environments\u0000where 3D seismic data are available, this workflow provides a template for\u0000geohazard assessments that will enhance the success of future scientific\u0000drilling.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"30 1","pages":"1-27"},"PeriodicalIF":1.2,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85936175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Soreghan, L. Beccaletto, K. Benison, S. Bourquin, G. Feulner, N. Hamamura, M. Hamilton, N. Heavens, L. Hinnov, Adam K. Huttenlocker, C. Looy, Lily S. Pfeifer, S. Pochat, Mehrdad Sardar Abadi, James J. Zambito
Abstract. Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian – the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies – boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed “Deep Dust,” held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on clarifying the scientific drivers and key sites for coring continuous sections of Permian continental (loess, lacustrine, and associated) strata that preserve high-resolution records. Combined, the two workshops hosted a total of 91 participants representing 14 countries, with broad expertise. Discussions at Deep Dust 1.0 (USA) focused on the primary research questions of paleoclimate, paleoenvironments, and paleoecology of icehouse collapse and the run-up to the Great Dying and both the modern and Permian deep microbial biosphere. Auxiliary science topics included tectonics, induced seismicity, geothermal energy, and planetary science. Deep Dust 1.0 also addressed site selection as well as scientific approaches, logistical challenges, and broader impacts and included a mid-workshop field trip to view the Permian of Oklahoma. Deep Dust 2.0 focused specifically on honing the European target. The Anadarko Basin (Oklahoma) and Paris Basin (France) represent the most promising initial targets to capture complete or near-complete stratigraphic coverage through continental successions that serve as reference points for western and eastern equatorial Pangaea.
{"title":"Report on ICDP Deep Dust workshops: probing continental climate of the late Paleozoic icehouse–greenhouse transition and beyond","authors":"G. Soreghan, L. Beccaletto, K. Benison, S. Bourquin, G. Feulner, N. Hamamura, M. Hamilton, N. Heavens, L. Hinnov, Adam K. Huttenlocker, C. Looy, Lily S. Pfeifer, S. Pochat, Mehrdad Sardar Abadi, James J. Zambito","doi":"10.5194/sd-28-93-2020","DOIUrl":"https://doi.org/10.5194/sd-28-93-2020","url":null,"abstract":"Abstract. Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian – the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies – boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed “Deep Dust,” held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on clarifying the scientific drivers and key sites for coring continuous sections of Permian continental (loess, lacustrine, and associated) strata that preserve high-resolution records. Combined, the two workshops hosted a total of 91 participants representing 14 countries, with broad expertise. Discussions at Deep Dust 1.0 (USA) focused on the primary research questions of paleoclimate, paleoenvironments, and paleoecology of icehouse collapse and the run-up to the Great Dying and both the modern and Permian deep microbial biosphere. Auxiliary science topics included tectonics, induced seismicity, geothermal energy, and planetary science. Deep Dust 1.0 also addressed site selection as well as scientific approaches, logistical challenges, and broader impacts and included a mid-workshop field trip to view the Permian of Oklahoma. Deep Dust 2.0 focused specifically on honing the European target. The Anadarko Basin (Oklahoma) and Paris Basin (France) represent the most promising initial targets to capture complete or near-complete stratigraphic coverage through continental successions that serve as reference points for western and eastern equatorial Pangaea.","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82305293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Aiken, R. Wessels, M. Cormier, F. Klingelhoefer, A. Battani, F. Rolandone, W. Roest, D. Boisson, K. Guerrier, R. Momplaisir, Nadine Ellouz-Zimmerman
Abstract. The Haiti region – bounded by two strike-slip faults expressed both onshore and offshore – offers a unique opportunity for an amphibious drilling project. The east–west (EW)-striking, left lateral strike-slip Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone bounding Haiti have similar slip rates and also define the northern and southern boundaries of the Gonâve Microplate. However, it remains unclear how these fault systems terminate at the eastern boundary of that microplate. From a plate tectonic perspective, the Enriquillo–Plantain Garden fault zone can be expected to act as an inactive fracture zone bounding the Cayman spreading system, but, surprisingly, this fault has been quite active during the last 500 years. Overall, little is understood in terms of past and present seismic and tsunami hazards along the Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone, their relative ages, maturity, lithology, and evolution – not even the origin of fluids escaping through the crust is known. Given these unknowns, the Haiti-Drill workshop was held in May 2019 to further develop an amphibious drilling project in the Haiti region on the basis of preproposals submitted in 2015 and their reviews. The workshop aimed to complete the following four tasks: (1) identify significant research questions; (2) discuss potential drilling scenarios and sites; (3) identify data, analyses, additional experts, and surveys needed; and (4) produce timelines for developing a full proposal. Two key scientific goals have been set, namely to understand the nature of young fault zones and the evolution of transpressional boundaries. Given these goals, drilling targets were then rationalized, creating a focus point for research and/or survey needs prior to drilling. Our most recent efforts are to find collaborators, analyze existing data, and to obtain sources of funding for the survey work that is needed.
{"title":"Haiti-Drill: an amphibious drilling project workshop","authors":"C. Aiken, R. Wessels, M. Cormier, F. Klingelhoefer, A. Battani, F. Rolandone, W. Roest, D. Boisson, K. Guerrier, R. Momplaisir, Nadine Ellouz-Zimmerman","doi":"10.5194/sd-28-49-2020","DOIUrl":"https://doi.org/10.5194/sd-28-49-2020","url":null,"abstract":"Abstract. The Haiti region – bounded by two strike-slip faults\u0000expressed both onshore and offshore – offers a unique opportunity for an\u0000amphibious drilling project. The east–west (EW)-striking, left lateral strike-slip Oriente–Septentrional fault zone and Enriquillo–Plantain Garden fault zone\u0000bounding Haiti have similar slip rates and also define the northern and southern\u0000boundaries of the Gonâve Microplate. However, it remains unclear how\u0000these fault systems terminate at the eastern boundary of that microplate.\u0000From a plate tectonic perspective, the Enriquillo–Plantain Garden fault zone\u0000can be expected to act as an inactive fracture zone bounding the Cayman\u0000spreading system, but, surprisingly, this fault has been quite active during\u0000the last 500 years. Overall, little is understood in terms of past and\u0000present seismic and tsunami hazards along the Oriente–Septentrional fault\u0000zone and Enriquillo–Plantain Garden fault zone, their relative ages,\u0000maturity, lithology, and evolution – not even the origin of fluids escaping through the crust is known. Given these unknowns, the Haiti-Drill workshop was held\u0000in May 2019 to further develop an amphibious drilling project in the Haiti\u0000region on the basis of preproposals submitted in 2015 and their reviews.\u0000The workshop aimed to complete the following four tasks: (1) identify significant research\u0000questions; (2) discuss potential drilling scenarios and sites; (3) identify\u0000data, analyses, additional experts, and surveys needed; and (4) produce\u0000timelines for developing a full proposal. Two key scientific goals have been set, namely to understand the nature of young fault zones and the evolution of transpressional boundaries. Given these goals, drilling targets were then\u0000rationalized, creating a focus point for research and/or survey needs prior to\u0000drilling. Our most recent efforts are to find collaborators, analyze\u0000existing data, and to obtain sources of funding for the survey work that is\u0000needed.\u0000","PeriodicalId":51840,"journal":{"name":"Scientific Drilling","volume":"60 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90259000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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