Canadian Journal of Earth Sciences最新文献_第8页

U-Pb zircon ages from metasedimentary and plutonic rocks in the Bras d'Or terrane of Cape Breton Island, Nova Scotia, Canada: Insights into the Ediacaran-Cambrian tectonomagmatic evolution of Ganderia 加拿大新斯科舍省布雷顿角岛brasd’or地块变质沉积岩和深成岩U-Pb锆石年龄:对Ganderia埃迪卡拉-寒武纪构造岩浆演化的启示

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2023-01-10 DOI: 10.1139/cjes-2022-0103

De Wet van Rooyen, S. Barr, C. White, J. Crowley

{"title":"U-Pb zircon ages from metasedimentary and plutonic rocks in the Bras d'Or terrane of Cape Breton Island, Nova Scotia, Canada: Insights into the Ediacaran-Cambrian tectonomagmatic evolution of Ganderia","authors":"De Wet van Rooyen, S. Barr, C. White, J. Crowley","doi":"10.1139/cjes-2022-0103","DOIUrl":"https://doi.org/10.1139/cjes-2022-0103","url":null,"abstract":"The Bras d’Or terrane of central Cape Breton Island, Nova Scotia, Canada, contains a well-preserved record of the Ediacaran to Early Cambrian evolution of Ganderia, a Gondwana-derived terrane in the northern Appalachian orogen. A complex assemblage of low- to high-grade metasedimentary rocks have varied detrital zircon signatures from LA-ICP-MS U-Pb zircon dating but combining 3 or more samples yielded representative age spectra which support correlation of the low- and high-grade metasedimentary rocks throughout the Bras d’Or terrane and the corresponding Ganderian Brookville terrane of southern New Brunswick. In quartzite samples from the McMillan Flowage Formation in the northwestern Bras d’Or terrane the youngest detrital zircons have ages >900 Ma, in contrast to previously studied psammitic and semi-pelitic samples from correlative units in the eastern Bras d’Or terrane in which youngest detrital ages are 620–600 Ma. Both quartzite and semi-pelitic samples from the McMillan Flowage Formation contain Neoproterozoic dates from zircon rims which reflect metamorphic overgrowths during peak metamorphism at ca. 550 Ma, providing a robust age for peak metamorphism in the Bras d’Or terrane that supports similar, albeit sparse, ages reported previously from monazite and titanite samples. This metamorphism is coeval with the emplacement of voluminous dioritic to granitic plutons that occur throughout the Bras d’Or terrane and formed in an Andean-type continental margin subduction zone. New U-Pb zircon ages presented here from plutons in the northern Bras d’Or terrane, combined with previously published ages, are consistent with subduction-related magmatism and associated metamorphism between ca. 575 Ma and 540 Ma.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"99 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85898381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Late Paleoarchean to Neoarchean sedimentation on Singhbhum craton, eastern India: a synthesis 印度东部Singhbhum克拉通晚古太古代至新太古代沉积:一个综合

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2023-01-10 DOI: 10.1139/cjes-2022-0050

S. De, Rajat Mazumder, T. Chaudhuri, W. Bauer

{"title":"Late Paleoarchean to Neoarchean sedimentation on Singhbhum craton, eastern India: a synthesis","authors":"S. De, Rajat Mazumder, T. Chaudhuri, W. Bauer","doi":"10.1139/cjes-2022-0050","DOIUrl":"https://doi.org/10.1139/cjes-2022-0050","url":null,"abstract":"Subaerial rise of Earth’s first continents took place 3.3-3.2 Ga years ago. This had significant influence on the ocean, atmosphere and biosphere. Two important sedimentological consequences of continental emersion were (1) development of terrestrial (alluvial fan-fluvial-aeolian) depositional systems and (2) formation of shallow-marine sedimentary basins near the continental margin. Late Paleoarchean-Neoarchean terrestrial deposits, including development of an extensive paleosol around 3.2 Ga and Meso-Neoarchean shallow-marine deposits have been reported from the Singhbhum Craton, eastern India from several localities. However, lateral and vertical changes in sedimentary facies associations and stratigraphic correlation between these terrestrial to shallow marine sedimentary deposits have not yet been investigated. In this paper we have reviewed the sedimentological characteristics of Late Paleoarchean to Neoarchean (3.2-2.8 Ga) stratigraphic successions of the Singhbhum Craton, and have discussed sea level change and mode of stratigraphic sequence building. Our analysis shows that Singhbhum granitoid complex was emplaced around 3.3 Ga in an intracontinental setting, resulting in high continental freeboard conditions that triggered terrestrial (alluvial fan-braided fluvial) sedimentation (Dhosrapahar Formation). Continental sedimentation continued until ca. 3.0 Ga. In the eastern (Simlipal Group), and western ( Birtola Formation), and southwestern (e Mankarchua, Mahagiri and Keonjhar formations) shallow-marine sedimentation occurred after 3.0 Ga as a result of transgression. However, in the northern part (Dhanjori Formation), continental sedimentation prevailed throughout the Archean. These late Paleoarchean to Neoarchean terrestrial and near-coastal successions of Singhbhum Craton should be the prime targets for intense geobiological research.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"7 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84221041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Precise U-Pb zircon dates from silicic super-eruptions during late Ediacaran extension in the Avalonian Caledonia terrane of southern New Brunswick, Canada 在加拿大新不伦瑞克省南部的阿瓦洛尼亚喀里多尼亚地体中，精确的U-Pb锆石年代来源于埃迪卡拉晚期伸展期的硅质超级喷发

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2023-01-09 DOI: 10.1139/cjes-2022-0100

A. Escribano, S. Barr, J. Crowley

{"title":"Precise U-Pb zircon dates from silicic super-eruptions during late Ediacaran extension in the Avalonian Caledonia terrane of southern New Brunswick, Canada","authors":"A. Escribano, S. Barr, J. Crowley","doi":"10.1139/cjes-2022-0100","DOIUrl":"https://doi.org/10.1139/cjes-2022-0100","url":null,"abstract":"The Coldbrook Group and related plutons in the Caledonian Highlands of southern New Brunswick contain voluminous late Ediacaran silicic rocks formed in a magmatic event not recognized in other parts of Avalonia in the northern Appalachian orogen. To better constrain the age and origin of these rocks, we used U-Pb zircon dating by laser ablation inductively coupled plasma (LA-ICP-MS) followed by chemical abrasion thermal ionization mass spectrometry (CA-TIMS). Four silicic samples were dated from the Coldbrook Group, one from the Bonnell Brook pluton, and, for comparison, a felsic lithic-crystal tuff sample from the older arc-related Broad River Group. Overlapping CA-TIMS dates of 551.57 ± 0.23, 551.38 ± 0.24 Ma, and 551.70 ± 0.20 Ma for samples from the lower, middle, and upper Coldbrook Group, respectively, and 551.71 ± 0.19 Ma for granite from the Bonnell Brook pluton show that these units crystallized in 760,000 years or less, consistent with a super-eruption event. Rhyolite from the uppermost unit of the Coldbrook Group yielded a younger date of 549.18 ± 0.09 Ma, but the large extent of that unit suggests the possibility of a second younger super-eruption. The Broad River Group sample yielded a date of 615.48 ± 0.16 Ma, consistent with previously published dates from that group and associated plutons. Differences in zircon chemistry between the Broad River Group sample and the late Ediacaran samples are consistent with the contrasting subduction-related vs within-plate extensional tectonic settings as suggested by previous studies of whole-rock petrological characteristics of the two age groups.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"118 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79037810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

An experimental baseline for ice-till strain indicators 冰冻应变指标的实验基线

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2023-01-09 DOI: 10.1139/cjes-2022-0074

L. Zoet, D. Hansen, Natasha Morgan-Witts, J. Menzies, Peter Sobol, N. Lord

{"title":"An experimental baseline for ice-till strain indicators","authors":"L. Zoet, D. Hansen, Natasha Morgan-Witts, J. Menzies, Peter Sobol, N. Lord","doi":"10.1139/cjes-2022-0074","DOIUrl":"https://doi.org/10.1139/cjes-2022-0074","url":null,"abstract":"Subglacial till can deform when overriding ice exerts shear traction at the ice-till interface. This deformation leaves a strain signature in the till, aligning grains in the direction of ice flow and producing a range of diagnostic microstructures. Constraining the conditions that produce these kinematic indicators is key to interpreting the myriad of features found in basal till deposits. Here we use a cryogenic ring shear device with transparent sample chamber walls to slip a ring of temperate ice over a till bed from which we examine the strain signature in the till. We use cameras mounted to the side of the ring shear and bead strings inserted in the till to estimate the strain distribution within the till layer. Following completion of the experiment, we extract and analyze AMS samples and create thin sections of the till bed for microstructure analysis. We then compare the AMS and microstructures with the observed strain history to examine the relationship between kinematic indicators and strain in a setting where shear traction is supplied by ice. We find that AMS fabrics show a high degree of clustering in regions of high strain near the ice-till interface. In the upper most zone of till, k1 eigenvector azimuths are generally aligned with ice flow, and S1 eigenvalues are high. However, S1 eigenvalues and the alignment of the k1 eigenvector with ice flow decrease nonlinearly with distance from the ice-till interface. There is a high occurrence of microshears in the zone of increased deformation.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"43 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77057623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Characterization of the Wager shear zone, Nunavut, Canada: Insights from microstructures and geochronology 加拿大努纳武特Wager剪切带的特征:来自微观结构和地质年代学的见解

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2023-01-01 DOI: 10.1139/cjes-2022-0031

I. Therriault, K. Larson, H. M. Steenkamp, F. Apen, R. Graziani, M. Soret, C. Guilmette, J. Cottle

引用次数: 0

The Ediacaran–Cambrian Chapel Island Formation of Newfoundland, Canada: evaluating the impact of outcrop quality on trace-fossil data sets at the Cambrian GSSP and less-explored sections 加拿大纽芬兰埃迪卡拉-寒武纪教堂岛组:评估露头质量对寒武纪GSSP和较少勘探剖面的痕迹化石数据集的影响

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2022-12-23 DOI: 10.1139/cjes-2022-0060

Romain Gougeon, M. Mángano, L. Buatois, G. Narbonne, Brittany Laing, M. Paz

{"title":"The Ediacaran–Cambrian Chapel Island Formation of Newfoundland, Canada: evaluating the impact of outcrop quality on trace-fossil data sets at the Cambrian GSSP and less-explored sections","authors":"Romain Gougeon, M. Mángano, L. Buatois, G. Narbonne, Brittany Laing, M. Paz","doi":"10.1139/cjes-2022-0060","DOIUrl":"https://doi.org/10.1139/cjes-2022-0060","url":null,"abstract":"In 1992, the Chapel Island Formation at Fortune Head was selected as the Cambrian GSSP, which was placed at the first appearance of the ichnotaxon Treptichnus pedum. Although the transition from the Ediacaran to the Cambrian was well studied in Fortune Head and Grand Bank Head, it is also exposed at Lewin’s Cove and Point May. Here, we report new ichnologic and sedimentologic data sets from the four localities. Ichnologic data sets consist of bioturbation intensities, burrow width and depth, ichnotaxonomic composition, and stratigraphic appearances. Sedimentologic data sets include sediment grain size, bed thickness and architecture, sandstone/mudstone ratio, and physical sedimentary structures. In addition, the quality of each outcrop is evaluated (i.e., accessibility, lateral and vertical continuity, stratigraphic completeness, and type of exposure). At the four localities, the base of the Cambrian can be placed at the first appearance of Treptichnus pedum or of vertical trace fossils of the T. pedum Ichno-Assemblage Zone. In addition, Fortune Head, Grand Bank Head, and Lewin’s Cove display increases in ichnodiversity and bioturbation intensities that are concomitant with the first appearance of penetrative trace fossils. Point May stands out as a section with low ichnodiversity and an inconsistent data set on bioturbation intensities. Its limited data set is a consequence of poor bed surface exposures, which impact negatively on the preservation and visibility of horizontal trace fossils. This study demonstrates that evaluation of outcrop quality should be an essential procedure to any research addressing evolutionary trends that took place at this critical time of the history of life.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"35 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83395346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A 500 ka Record of Volcanism and Paleoenvironment in the northern Garibaldi Volcanic Belt, British Columbia. 不列颠哥伦比亚省加里波第火山带北部500 ka火山活动与古环境记录。

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2022-12-15 DOI: 10.1139/cjes-2022-0101

M. Harris, J. Russell, Alexander M. Wilson, B. Jicha

{"title":"A 500 ka Record of Volcanism and Paleoenvironment in the northern Garibaldi Volcanic Belt, British Columbia.","authors":"M. Harris, J. Russell, Alexander M. Wilson, B. Jicha","doi":"10.1139/cjes-2022-0101","DOIUrl":"https://doi.org/10.1139/cjes-2022-0101","url":null,"abstract":"The Mount Meager Volcanic complex (MMVC) is one of eight major calc-alkaline volcanic centres within the Garibaldi volcanic belt, Canada. MMVC volcanism spans ~2 Ma and has been mainly intermediate to felsic in composition. However, small volume mafic centres are located around the periphery of the Mount Meager massif and have been collectively referred to as the Mosaic Assemblage or Mount Meager basalts. Here we present new 40Ar/39Ar ages and expanded chemical datasets for the MMVC mafic rocks. We show that mafic eruptive ages are both older and longer-lived than previously interpreted, spanning the last ~450 ka, and occurring in four episodes at, ~440, 200, 106, and 17 ka. We also find that chemical signatures for the MMVC mafic rocks have evolved across the four periods, fluctuating from ‘OIB’-like melt characteristics, to more typical slab-influenced, calc-alkaline, before returning to ‘OIB’-like in the youngest phase. These findings provide the first evidence of a temporal-chemical evolution of melt sourcing for the Garibaldi belt volcanism. Lastly, field mapping has identified edifices and deposits that are glaciovolcanic in origin (vs. non-glaciovolcanic) which are used in conjunction with our new 40Ar/39Ar age estimates to document the presence or absence of Coast Mountain sectors of earlier Cordilleran ice sheets in SW British Columbia over the last 500 ka.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"35 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80808676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Lower Cretaceous sequence of western Alaska – demise of the Koyukuk terrane? 阿拉斯加西部的下白垩纪层序——科尤库克地体的消亡?

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2022-12-14 DOI: 10.1139/cjes-2022-0041

T. Hudson, R. Blodgett, F. Wilson

{"title":"The Lower Cretaceous sequence of western Alaska – demise of the Koyukuk terrane?","authors":"T. Hudson, R. Blodgett, F. Wilson","doi":"10.1139/cjes-2022-0041","DOIUrl":"https://doi.org/10.1139/cjes-2022-0041","url":null,"abstract":"Lower Cretaceous marine sedimentary rocks, deposited in shallow shelf and basin settings and unconformity-bound, are well exposed in southwest Alaska. Collections of Early Cretaceous fossils from across western Alaska show that similar and coeval Lower Cretaceous clastic rocks are widely distributed though only locally exposed. Volcanic rocks become an important part of the Lower Cretaceous sequence in the Yukon-Koyukuk basin where they have been interpreted to represent a mobile intra-oceanic island arc, the Koyukuk terrane, that collided with Arctic Alaska to form the Brooks Range orogen. The volcanic rocks are chemically unlike Aleutian arc rocks but share compositional characteristics with spatially related, mid-Cretaceous alkaline intrusive rocks. The volcanic-bearing sequence was also deposited on an angular unconformity, includes both shallow shelf and basin depositional settings, and is unconformably overlain by mid-Cretaceous clastic rocks. The volcanic rocks are therefore considered part of the Lower Cretaceous sequence now identified across western Alaska. In this interpretation, the Lower Cretaceous volcanic rocks are an initial expression of the mid-Cretaceous tectonic regime that included extensional exhumation and subsidence, crustal and upper mantle melting, and high temperature metamorphism in the hinterland of the Brooks Range orogen. The Cretaceous heating that led to hinterland crust and upper mantle change may have been caused by deep mantle disturbances in a post-subduction setting. This interpretation has implications for the timing of contractional orogenesis, the location and nature of the related continental borderland, and the tectonic setting for development of the Anguyucham and related oceanic terranes.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"32 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83173520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ontogeny of Euphanerops longaevus from the Upper Devonian Miguasha Fossil-Fish-Lagerstätte and comparison with the skeletogenesis of the Sea Lamprey Petromyzon marinus 米洼沙上泥盆统长角七鳃鳗(Euphanerops longaevus)的个体发育Fossil-Fish-Lagerstätte及与海洋七鳃鳗(Petromyzon marinus)骨骼发育的比较

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2022-12-09 DOI: 10.1139/cjes-2022-0062

Marion Chevrinais, C. Morel, C. B. Renaud, R. Cloutier

{"title":"Ontogeny of Euphanerops longaevus from the Upper Devonian Miguasha Fossil-Fish-Lagerstätte and comparison with the skeletogenesis of the Sea Lamprey Petromyzon marinus","authors":"Marion Chevrinais, C. Morel, C. B. Renaud, R. Cloutier","doi":"10.1139/cjes-2022-0062","DOIUrl":"https://doi.org/10.1139/cjes-2022-0062","url":null,"abstract":"Ontogeny is of paramount importance to understand evolutionary relationships of organisms. However, in the fossil record, early developmental stages are rarely preserved because of their unmineralized skeleton. Here, we describe the ontogeny of the Devonian jawless fish Euphanerops longaevus based on observations from more than 3,500 specimens. The ontogeny of Euphanerops is compared with the development of the median fins of the extant jawless fish, the Sea Lamprey (Petromyzon marinus). From a sub-sample of 216 specimens of Euphanerops, we define three ontogenetic stages: larvae (2-38 mm total length; mostly composed of “Scaumenella mesacanthi”); juveniles (28-98 mm total length); and adults (≥ 90 mm total length) based on the degree of skeletal development, chemical and microscopic compositions. Larvae display three cranial plates, a simple branchial apparatus, notochordal elements and caudal fin supports. In juveniles, we document the development of paired anteroventral, anal and median dorsal fins. Given how little information is generally available on ostracoderm ontogeny, the growth series of Euphanerops provides an unparalleled opportunity to understand the development of early vertebrate characters.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"28 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84457971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Glacial Microsedimentology – a new lens to investigate Glacial Sediments – a review 冰川微沉积学——研究冰川沉积物的新视角

IF 1.4 4区地球科学

Canadian Journal of Earth Sciences Pub Date : 2022-12-09 DOI: 10.1139/cjes-2022-0048

J. Menzies

{"title":"Glacial Microsedimentology – a new lens to investigate Glacial Sediments – a review","authors":"J. Menzies","doi":"10.1139/cjes-2022-0048","DOIUrl":"https://doi.org/10.1139/cjes-2022-0048","url":null,"abstract":"Glacial sediment research using thin sections began post-1945. Microsedimentology examines sediments at the microscopic level deriving insights into the processes of glacial erosion, transport, and deposition. Two issues exist (1) the difficulty by some in recognizing microstructures in thin section; and (2) the absence of quantitative data making data reproduction difficult. The latter is hard to resolve but more image capture and software methodologies are now becoming available at reasonable costs. Thin sections are two-dimensional sections of three-dimensional objects, and this must be considered when measurements, fabrics and other data are assessed. Research into the micro-aspects of glacial sediments followed a typical scientific trajectory: thin sections description with little uniformity or common ‘language’ for observed microstructures: standardization allowed comparison between different sediments; with standardization, came an open-ended classification; and with cross-comparison with multiple thin sections - a quantitative means of study needs developed. It has become apparent that the basic principles of structural geology had to be applied. Thus, micromorphology has subsumed into a microsedimentological study of glacial sediments where stress parameters, structural fabrics and the mapping of deformation structures and contextual integration allows an understanding of how these sediments have been formed. Examples of the development stages of glacial micromorphology / sedimentology are presented here as well as discussion of future avenues of study. In addition, multiple thin sections are used to illustrate the many aspects of glacial micromorphology and the parameters necessary to understand glacial sedimentology and the processes of glacial sedimentation.","PeriodicalId":9567,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"39 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79067734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2