Pub Date : 2022-09-27DOI: 10.1080/11035897.2022.2042377
H. Mutvei
ABSTRACT The structure of the shell wall in the Ordovician Orthoceras differs from that in the extant Nautilus. It consists of two equal thick layers: an outer probably nacreous layer and an inner prismatic layer. The two layers are separated from each other by a thin intermediate sub-layer that is rich in organic substance and has indistinct boundaries. The intermediate sub-layer and the inner prismatic layer contain a hitherto undetected pore-canal network that consists of vertical and horizontal canals. Horizontal canals are arranged in a single layer in the outermost part of the intermediate sub-layer. The vertical canals are arranged in parallel rows, and the canals in each row open into one of the horizontal canals. The canals have thin walls of calcified organic fibres. The walls are preserved in the intermediate sub-layer, whereas in the inner prismatic layer, they are partially dissolved. The canal network is absent in the shell wall of the extant Nautilus, but the horizontal canals occur in the shell wall of the Carboniferous orthocerid-like coleoid Mitorthoceras and the bactritid-like coleoid Shimanskya. Thus, the pore-canal network had an important, still unknown, function for the animal, and it existed, without changes, at least 150 ma.
{"title":"Hitherto undetected pore-canal network in the shell wall of the Ordovician Orthoceras from Baltoscandia (Cephalopoda: orthoceratida, calciosiphonata)","authors":"H. Mutvei","doi":"10.1080/11035897.2022.2042377","DOIUrl":"https://doi.org/10.1080/11035897.2022.2042377","url":null,"abstract":"ABSTRACT The structure of the shell wall in the Ordovician Orthoceras differs from that in the extant Nautilus. It consists of two equal thick layers: an outer probably nacreous layer and an inner prismatic layer. The two layers are separated from each other by a thin intermediate sub-layer that is rich in organic substance and has indistinct boundaries. The intermediate sub-layer and the inner prismatic layer contain a hitherto undetected pore-canal network that consists of vertical and horizontal canals. Horizontal canals are arranged in a single layer in the outermost part of the intermediate sub-layer. The vertical canals are arranged in parallel rows, and the canals in each row open into one of the horizontal canals. The canals have thin walls of calcified organic fibres. The walls are preserved in the intermediate sub-layer, whereas in the inner prismatic layer, they are partially dissolved. The canal network is absent in the shell wall of the extant Nautilus, but the horizontal canals occur in the shell wall of the Carboniferous orthocerid-like coleoid Mitorthoceras and the bactritid-like coleoid Shimanskya. Thus, the pore-canal network had an important, still unknown, function for the animal, and it existed, without changes, at least 150 ma.","PeriodicalId":55094,"journal":{"name":"Gff","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47280354","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2047773
A. Gubanov, S. Bakayeva, J. R. Ebbestad, O. Bogolepova
ABSTRACT The oldest known specimens of the enigmatic mollusc Jinonicella kolebabai Pokorný, 1978 are redescribed from Middle Ordovician strata of Ukraine and Belarus. The phosphatic internal moulds preserve imprints of growth lines, hitherto only documented in Silurian specimens. The persistent distribution of Jinonicella in the Baltoscandian basin of the Russian Platform suggests that this was the centre of origin of this taxon. During the Silurian, Jinonicella inhabited Siberia and Laurentia, and the smaller European terranes of Bohemia and the Carnic Alps. In the Devonian, Jinonicella is reported from Laurentia, Bohemia and the Rhenish Massif.
{"title":"The Middle Ordovician Jinonicella (Mollusca) from Belarus and Ukraine","authors":"A. Gubanov, S. Bakayeva, J. R. Ebbestad, O. Bogolepova","doi":"10.1080/11035897.2022.2047773","DOIUrl":"https://doi.org/10.1080/11035897.2022.2047773","url":null,"abstract":"ABSTRACT The oldest known specimens of the enigmatic mollusc Jinonicella kolebabai Pokorný, 1978 are redescribed from Middle Ordovician strata of Ukraine and Belarus. The phosphatic internal moulds preserve imprints of growth lines, hitherto only documented in Silurian specimens. The persistent distribution of Jinonicella in the Baltoscandian basin of the Russian Platform suggests that this was the centre of origin of this taxon. During the Silurian, Jinonicella inhabited Siberia and Laurentia, and the smaller European terranes of Bohemia and the Carnic Alps. In the Devonian, Jinonicella is reported from Laurentia, Bohemia and the Rhenish Massif.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"106 - 110"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43385042","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2064543
J. S. Peel
ABSTRACT Rare phosphatised fragments within small shelly fossil assemblages from the upper Henson Gletscher Formation (Cambrian, Miaolingian Series, Wuliuan Stage) of North Greenland (Laurentia) are described as Dietericambria hensoniensis n. gen. n. sp. Two pairs of minute cephalic limbs promote comparison with stem-group pentastomids, best known from the late Cambrian (Furongian) Orsten Lagerstätten of Sweden. The North Greenland occurrence is interpreted as the oldest yet described tongue worm and extends the record of pentastomids by about 15 m.y. Dietericambria hensoniensis preserves a unique median axial complex of uncertain function, probably an attachment organ; a mouth has not been identified. Isolated hooks and spicules in the samples from the Henson Gletscher Formation are compared to the grasping hooks and copulatory spicules of the extant pentastomid Raillietiella, although their interpretation is speculative.
北格陵兰岛(Laurentia)上Henson Gletscher组(寒武系，miollingian系列，Wuliuan阶段)的小壳类化石组合中罕见的磷化碎片被描述为Dietericambria hensoniensis n. gen. n. sp.。两对微小的头状肢与瑞典晚寒武世(Furongian) Orsten Lagerstätten的茎群五形肢进行了比较。北格陵兰岛的出现被解释为迄今为止最古老的舌虫，并将pentastomids的记录延长了约15英里。hensoniensis Dietericambria保留了一个独特的功能不确定的中轴复合体，可能是一个附着器官;嘴巴还没有被确认。我们将Henson Gletscher组样本中孤立的钩和针状体与现存的五翼虫Raillietiella的抓钩和交配针状体进行了比较，尽管它们的解释是推测性的。
{"title":"The oldest tongue worm: a stem-group pentastomid arthropod from the early middle Cambrian (Wuliuan Stage) of North Greenland (Laurentia)","authors":"J. S. Peel","doi":"10.1080/11035897.2022.2064543","DOIUrl":"https://doi.org/10.1080/11035897.2022.2064543","url":null,"abstract":"ABSTRACT Rare phosphatised fragments within small shelly fossil assemblages from the upper Henson Gletscher Formation (Cambrian, Miaolingian Series, Wuliuan Stage) of North Greenland (Laurentia) are described as Dietericambria hensoniensis n. gen. n. sp. Two pairs of minute cephalic limbs promote comparison with stem-group pentastomids, best known from the late Cambrian (Furongian) Orsten Lagerstätten of Sweden. The North Greenland occurrence is interpreted as the oldest yet described tongue worm and extends the record of pentastomids by about 15 m.y. Dietericambria hensoniensis preserves a unique median axial complex of uncertain function, probably an attachment organ; a mouth has not been identified. Isolated hooks and spicules in the samples from the Henson Gletscher Formation are compared to the grasping hooks and copulatory spicules of the extant pentastomid Raillietiella, although their interpretation is speculative.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"97 - 105"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47459590","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2086290
S. Wastegård
ABSTRACT This paper presents a review on more than hundred years of palaeoenvironmental research in Sweden; from early descriptions of peat and tufa deposits in the late nineteenth and early twentieth centuries to multiproxy transfer function studies in the late twentieth and early twenty-first centuries CE. Research on Holocene climate variability has a long history in Sweden and many ideas and concepts about changes in temperature and precipitation during the Holocene originated in Fennoscandia. The Holocene climate evolution in Sweden follows a pattern in common for many northern latitude records with a rapid warming starting at the Pleistocene–Holocene boundary at c. 11 650 cal a BP, followed by the middle Holocene thermal maximum between c. 8000 and 5000 cal a BP. A change to colder and wetter conditions starts c. 4000 cal a BP and lasts until the late 1800 s CE. There is evidence for climatic anomalies such as the 8.2 and 4.2 ka BP events and the Little Ice Age (LIA) but only inconclusive evidence for other events, such as the 10.3 ka BP event. The main pattern of Holocene climate and environmental evolution is well known for most parts of Sweden, but the present review also shows that several research questions remain to be addressed.
本文回顾了瑞典一百多年来的古环境研究；从十九世纪末和二十世纪初对泥炭和凝灰岩矿床的早期描述，到二十世纪末和二十一世纪初的多氧传递函数研究。瑞典对全新世气候变化的研究历史悠久，许多关于全新世温度和降水变化的想法和概念起源于芬诺斯坎迪亚。瑞典全新世气候演变遵循许多北纬记录的共同模式，从更新世-全新世边界开始的快速变暖约为11 650 cal a BP，然后是全新世中期的最大热值约为8000至5000 cal a BP。向更冷、更潮湿的条件的转变从大约4000卡每BP开始，一直持续到1800年末 s CE。有证据表明气候异常，如8.2和4.2卡BP事件以及小冰期（LIA），但只有不确定的证据表明其他事件，如10.3卡BP事件。瑞典大部分地区都知道全新世气候和环境演变的主要模式，但本综述也表明，一些研究问题仍有待解决。
{"title":"The Holocene of Sweden – a review","authors":"S. Wastegård","doi":"10.1080/11035897.2022.2086290","DOIUrl":"https://doi.org/10.1080/11035897.2022.2086290","url":null,"abstract":"ABSTRACT This paper presents a review on more than hundred years of palaeoenvironmental research in Sweden; from early descriptions of peat and tufa deposits in the late nineteenth and early twentieth centuries to multiproxy transfer function studies in the late twentieth and early twenty-first centuries CE. Research on Holocene climate variability has a long history in Sweden and many ideas and concepts about changes in temperature and precipitation during the Holocene originated in Fennoscandia. The Holocene climate evolution in Sweden follows a pattern in common for many northern latitude records with a rapid warming starting at the Pleistocene–Holocene boundary at c. 11 650 cal a BP, followed by the middle Holocene thermal maximum between c. 8000 and 5000 cal a BP. A change to colder and wetter conditions starts c. 4000 cal a BP and lasts until the late 1800 s CE. There is evidence for climatic anomalies such as the 8.2 and 4.2 ka BP events and the Little Ice Age (LIA) but only inconclusive evidence for other events, such as the 10.3 ka BP event. The main pattern of Holocene climate and environmental evolution is well known for most parts of Sweden, but the present review also shows that several research questions remain to be addressed.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"126 - 149"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47048016","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2083224
J. Majka, Adam Włodek, E. Jonsson, K. Högdahl
ABSTRACT Three different types of secondary coronas developed around monazite-(Ce) were discovered in altered metavolcanic rocks closely associated with the Palaeoproterozoic apatite-iron oxide ore deposit in Grängesberg, Sweden. All three types of reaction coronas include fluorapatite that is either rimmed by allanite-(Ce), REE-fluorocarbonate(s), or hingganite-(Y). The latter mineral has not been previously observed among monazite breakdown products. A unique feature of the described reaction coronas around monazite is their spatial proximity to each other, not exceeding a few hundreds of micrometres. We infer that the observed, strongly contrasting monazite breakdown assemblages highlight the presence of a heterogeneous fluid that mediated these microscale decomposition reactions. Thus, it is emphasized that metasomatic fluid variability in natural systems may often be too large to be predicted and reproduced experimentally.
{"title":"Contrasting coronas: microscale fluid variation deduced from monazite breakdown products in altered metavolcanic rocks associated with the Grängesberg apatite-iron oxide ore, Bergslagen, Sweden","authors":"J. Majka, Adam Włodek, E. Jonsson, K. Högdahl","doi":"10.1080/11035897.2022.2083224","DOIUrl":"https://doi.org/10.1080/11035897.2022.2083224","url":null,"abstract":"ABSTRACT Three different types of secondary coronas developed around monazite-(Ce) were discovered in altered metavolcanic rocks closely associated with the Palaeoproterozoic apatite-iron oxide ore deposit in Grängesberg, Sweden. All three types of reaction coronas include fluorapatite that is either rimmed by allanite-(Ce), REE-fluorocarbonate(s), or hingganite-(Y). The latter mineral has not been previously observed among monazite breakdown products. A unique feature of the described reaction coronas around monazite is their spatial proximity to each other, not exceeding a few hundreds of micrometres. We infer that the observed, strongly contrasting monazite breakdown assemblages highlight the presence of a heterogeneous fluid that mediated these microscale decomposition reactions. Thus, it is emphasized that metasomatic fluid variability in natural systems may often be too large to be predicted and reproduced experimentally.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"89 - 96"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41373506","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2042378
M. Zatoń, O. Vinn, U. Toom, J. Słowiński
ABSTRACT A new genus and species of encrusting tentaculitoid, Lindstroemiella eichwaldi, from the Silurian (Ludfordian Stage, Ludlow) of Saaremaa Island in Estonia, is described. This tentaculitoid shares common structural features (inwardly directed pseudopunctae and vesicles) with Anticalyptraea, but differs from the latter in having a spirally coiled, microconchid-like shell with a variously oriented aperture, thin and sharp transverse ridges and lacking an inverted cone-like morphology. Unlike other tentaculitoids (microconchids, trypanoporids, cornulitids), these encrusters, unique with respect to morphology and shell structure, have so far not been taxonomically classified at the ordinal level. Now, taking into account that such tentaculitoids are taxonomically and morphologically more diverse than previously assumed, we propose to include them in a separate order Anticalyptraeida. Unlike microconchids and cornulitids, anticalyptraeids are the least studied group of tentaculitoids and thus poorly recognized. In part, this may be due to their misidentification with associated spirally coiled microconchids, to which anticalyptraeids are very similar at juvenile stages. http://www.zoobank.org/lsid:zoobank.org:act:C1E9D9A4-555E-4F5A-BEDC-8046CCA58BD9
{"title":"New encrusting tentaculitoids from the Silurian of Estonia and taxonomic status of Anticalyptraea Quenstedt, 1867","authors":"M. Zatoń, O. Vinn, U. Toom, J. Słowiński","doi":"10.1080/11035897.2022.2042378","DOIUrl":"https://doi.org/10.1080/11035897.2022.2042378","url":null,"abstract":"ABSTRACT A new genus and species of encrusting tentaculitoid, Lindstroemiella eichwaldi, from the Silurian (Ludfordian Stage, Ludlow) of Saaremaa Island in Estonia, is described. This tentaculitoid shares common structural features (inwardly directed pseudopunctae and vesicles) with Anticalyptraea, but differs from the latter in having a spirally coiled, microconchid-like shell with a variously oriented aperture, thin and sharp transverse ridges and lacking an inverted cone-like morphology. Unlike other tentaculitoids (microconchids, trypanoporids, cornulitids), these encrusters, unique with respect to morphology and shell structure, have so far not been taxonomically classified at the ordinal level. Now, taking into account that such tentaculitoids are taxonomically and morphologically more diverse than previously assumed, we propose to include them in a separate order Anticalyptraeida. Unlike microconchids and cornulitids, anticalyptraeids are the least studied group of tentaculitoids and thus poorly recognized. In part, this may be due to their misidentification with associated spirally coiled microconchids, to which anticalyptraeids are very similar at juvenile stages. http://www.zoobank.org/lsid:zoobank.org:act:C1E9D9A4-555E-4F5A-BEDC-8046CCA58BD9","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"111 - 117"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46404774","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2071335
Yaocen Pan, E. Seidel, C. Juhlin, Christian Hübscher, D. Sopher
ABSTRACT New seismic profiles located within the Bornholm Gat in the SW Baltic Sea area image Late Cretaceous-Paleogene inversion and exhumation of a previously poorly characterized narrow crustal zone in the southern end of the Sorgenfrei–Tornquist Zone (STZ), a long pre-Alpine tectonic lineament in Europe. Thrusts and pop-up structures developed along the inversion axis accompanied by subsidence troughs on its sides. Stratigraphic analysis of chalk deposits indicates that structural shortening and inversion resulted from compressional deformation. Marginal troughs formed synchronously to inversion and adjacent to the tectonically active slope, where sediment redeposition was focused. Deposition of chalk units, composed predominantly of contourites and gravity-driven sedimentation were largely controlled by inversion tectonics and influenced by intensification of bottom currents. We find that allochthonous chalk has been buried in horizontally deposited autochthonous (pelagic) chalk. An erosional unconformity represents the base of the Maastrichtian and marks the onset of along slope deposition due to a more hydrodynamic environment. The revealed asymmetric inversion across the STZ with fold tightening and superposition of NE-NW folds attest to more than one pulse during the Late Cretaceous-Cenozoic inversion. The STZ may belong to the end-member mode of intraplate foreland basins resulting from a far-field NE-SW compression transmitted from the Africa-Iberia-Europe convergence. The intraplate stress associated with the following Maastrichtian enhanced collisional coupling between the Alpine-Carpathian orogen and its foreland, which is widely recognized (e.g., the Mid-Polish Trough, the Bohemian Massif and the Central Graben), may also have had its maximum extent to the northeast in southern Sweden.
{"title":"Inversion tectonics in the Sorgenfrei–Tornquist Zone: insight from new marine seismic data at the Bornholm Gat, SW Baltic Sea","authors":"Yaocen Pan, E. Seidel, C. Juhlin, Christian Hübscher, D. Sopher","doi":"10.1080/11035897.2022.2071335","DOIUrl":"https://doi.org/10.1080/11035897.2022.2071335","url":null,"abstract":"ABSTRACT New seismic profiles located within the Bornholm Gat in the SW Baltic Sea area image Late Cretaceous-Paleogene inversion and exhumation of a previously poorly characterized narrow crustal zone in the southern end of the Sorgenfrei–Tornquist Zone (STZ), a long pre-Alpine tectonic lineament in Europe. Thrusts and pop-up structures developed along the inversion axis accompanied by subsidence troughs on its sides. Stratigraphic analysis of chalk deposits indicates that structural shortening and inversion resulted from compressional deformation. Marginal troughs formed synchronously to inversion and adjacent to the tectonically active slope, where sediment redeposition was focused. Deposition of chalk units, composed predominantly of contourites and gravity-driven sedimentation were largely controlled by inversion tectonics and influenced by intensification of bottom currents. We find that allochthonous chalk has been buried in horizontally deposited autochthonous (pelagic) chalk. An erosional unconformity represents the base of the Maastrichtian and marks the onset of along slope deposition due to a more hydrodynamic environment. The revealed asymmetric inversion across the STZ with fold tightening and superposition of NE-NW folds attest to more than one pulse during the Late Cretaceous-Cenozoic inversion. The STZ may belong to the end-member mode of intraplate foreland basins resulting from a far-field NE-SW compression transmitted from the Africa-Iberia-Europe convergence. The intraplate stress associated with the following Maastrichtian enhanced collisional coupling between the Alpine-Carpathian orogen and its foreland, which is widely recognized (e.g., the Mid-Polish Trough, the Bohemian Massif and the Central Graben), may also have had its maximum extent to the northeast in southern Sweden.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"71 - 88"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47137508","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}
Pub Date : 2022-04-03DOI: 10.1080/11035897.2022.2097737
Mikael Siversson, P. Cederström, H. E. Ryan
ABSTRACT Examination of isolated shark teeth from the uppermost lower Campanian Gonioteuthis quadrata scaniensis Zone of southern Sweden revealed the presence of a rare, previously undescribed lamniform shark. The unusually small-sized anterior teeth, variable presence of a short and shallow median groove, cusplet shape and outline of posterior teeth indicate a dallasiellid affinity and the species is formally described as Dallasiella brachyodon sp. nov. It is the youngest record of dallasiellids and adds to the extraordinarily high diversity of lamniform sharks in the uppermost lower Campanian of the Kristianstad Basin. Over its 18 Ma range, Dallasiella appears to have increased in body size and developed teeth with relatively broader cusps, indicating enhanced capabilities for tackling larger prey.
{"title":"A new dallasiellid shark from the lower Campanian (Upper Cretaceous) of Sweden","authors":"Mikael Siversson, P. Cederström, H. E. Ryan","doi":"10.1080/11035897.2022.2097737","DOIUrl":"https://doi.org/10.1080/11035897.2022.2097737","url":null,"abstract":"ABSTRACT Examination of isolated shark teeth from the uppermost lower Campanian Gonioteuthis quadrata scaniensis Zone of southern Sweden revealed the presence of a rare, previously undescribed lamniform shark. The unusually small-sized anterior teeth, variable presence of a short and shallow median groove, cusplet shape and outline of posterior teeth indicate a dallasiellid affinity and the species is formally described as Dallasiella brachyodon sp. nov. It is the youngest record of dallasiellids and adds to the extraordinarily high diversity of lamniform sharks in the uppermost lower Campanian of the Kristianstad Basin. Over its 18 Ma range, Dallasiella appears to have increased in body size and developed teeth with relatively broader cusps, indicating enhanced capabilities for tackling larger prey.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"118 - 125"},"PeriodicalIF":1.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49474462","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}
Pub Date : 2022-01-02DOI: 10.1080/11035897.2021.2020333
T. Paiste, P. Männik, T. Meidla
ABSTRACT The boundaries of the Sandbian Stage are defined by graptolites. Because of their rare occurrence in the Estonian part of the Baltoscandian palaeobasin, other fossils, including conodonts, are used for biostratigraphy as good alternatives. Since the definition of Sandbian Stage/Age in 2002, information about conodonts from this time interval in Baltsocandia has improved considerably. In this paper, existing data on Sandbian conodont faunas from the Estonian part of the Baltoscandian palaeobasin, including the most recent information from the Velise V-97 core section (western part of mainland Estonia), is evaluated. Dating of these strata in the region is addressed and partly updated. Comparison of conodont successions from other regions of Baltoscandia with those from the Estonian sections is used to check consistency of known conodont zones. The rich conodont succession from the Velise V-97 drill core is considered a representative one for the Sandbian-age carbonate ramp environment in Baltoscandia. Most of the principal conodont zones within the Sandbian Stage were recognised whilst the lower and upper boundary intervals of the stage are poorly resolved. Despite the rich conodont faunas available, the boundaries of the Sandbian Stage are currently not clearly definable in the conodont succession. However, further detailed studies on the morphology and evolution of the earliest Amorphognathus (A. inaequalis and A. tvaerensis in particular), based on rich and well preserved material from different parts of Baltoscandia, might provide useful criteria for location of the Sandbian and Katian boundaries in non-graptolitiferous carbonate sections.
{"title":"Sandbian (Late Ordovician) conodonts in Estonia: distribution and biostratigraphy","authors":"T. Paiste, P. Männik, T. Meidla","doi":"10.1080/11035897.2021.2020333","DOIUrl":"https://doi.org/10.1080/11035897.2021.2020333","url":null,"abstract":"ABSTRACT The boundaries of the Sandbian Stage are defined by graptolites. Because of their rare occurrence in the Estonian part of the Baltoscandian palaeobasin, other fossils, including conodonts, are used for biostratigraphy as good alternatives. Since the definition of Sandbian Stage/Age in 2002, information about conodonts from this time interval in Baltsocandia has improved considerably. In this paper, existing data on Sandbian conodont faunas from the Estonian part of the Baltoscandian palaeobasin, including the most recent information from the Velise V-97 core section (western part of mainland Estonia), is evaluated. Dating of these strata in the region is addressed and partly updated. Comparison of conodont successions from other regions of Baltoscandia with those from the Estonian sections is used to check consistency of known conodont zones. The rich conodont succession from the Velise V-97 drill core is considered a representative one for the Sandbian-age carbonate ramp environment in Baltoscandia. Most of the principal conodont zones within the Sandbian Stage were recognised whilst the lower and upper boundary intervals of the stage are poorly resolved. Despite the rich conodont faunas available, the boundaries of the Sandbian Stage are currently not clearly definable in the conodont succession. However, further detailed studies on the morphology and evolution of the earliest Amorphognathus (A. inaequalis and A. tvaerensis in particular), based on rich and well preserved material from different parts of Baltoscandia, might provide useful criteria for location of the Sandbian and Katian boundaries in non-graptolitiferous carbonate sections.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"9 - 23"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44962392","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}
Pub Date : 2022-01-02DOI: 10.1080/11035897.2022.2032822
M. Streng, J. A. Rasmussen, J. R. Ebbestad, Thomas Weidner
ABSTRACT An Early Ordovician fauna of linguliform brachiopods and euconodonts is described from the Alum Shale Formation in northernmost Västerbotten County, northern Sweden. The fauna was recovered from a single carbonate concretion collected at an exposure near the northern shore of Lake Storvindeln. Despite of the fragmentary and tectonized preservation of the obtained fossils, at least eight different taxa of linguliform brachiopods and four species of euconodonts could be identified. Among the brachiopods, the ephippelasmatid Pomeraniotreta biernatae Bednarczyk, 1986 is most common; it is associated among others with the acrotretids Eurytreta cf. sabrinae (Callaway, 1877) and Ottenbyella sp., and a spinose specimen potentially representing the zhanatellid Thysanotos. Two of the brachiopod taxa appear to present new species, Pomeraniotreta n. sp. and Mytoella? n. sp., but additional material would be needed for a formal description. Euconodont specimens are rare and comprise coniform elements of Drepanodus arcuatus Pander, 1856, Drepanoistodus aff. amoenus (Lindström, 1955) sensu Löfgren (1994), Paroistodus numarcuatus (Lindström, 1955) and Rossodus aff. manitouensis Repetski & Ethington, 1983. Evaluation of the stratigraphic distribution of the different taxa of brachiopods and euconodonts under consideration of the local geology, suggests that the investigated sample represents a level in the upper part of the Tremadocian (Tr2) part of the Alum Shale Formation. The fauna represents the northernmost occurrence of age diagnostic Early Ordovician (Tremadocian) fossils in Sweden.
{"title":"First record of an Early Ordovician brachiopod and conodont fauna from Lapland, Sweden","authors":"M. Streng, J. A. Rasmussen, J. R. Ebbestad, Thomas Weidner","doi":"10.1080/11035897.2022.2032822","DOIUrl":"https://doi.org/10.1080/11035897.2022.2032822","url":null,"abstract":"ABSTRACT An Early Ordovician fauna of linguliform brachiopods and euconodonts is described from the Alum Shale Formation in northernmost Västerbotten County, northern Sweden. The fauna was recovered from a single carbonate concretion collected at an exposure near the northern shore of Lake Storvindeln. Despite of the fragmentary and tectonized preservation of the obtained fossils, at least eight different taxa of linguliform brachiopods and four species of euconodonts could be identified. Among the brachiopods, the ephippelasmatid Pomeraniotreta biernatae Bednarczyk, 1986 is most common; it is associated among others with the acrotretids Eurytreta cf. sabrinae (Callaway, 1877) and Ottenbyella sp., and a spinose specimen potentially representing the zhanatellid Thysanotos. Two of the brachiopod taxa appear to present new species, Pomeraniotreta n. sp. and Mytoella? n. sp., but additional material would be needed for a formal description. Euconodont specimens are rare and comprise coniform elements of Drepanodus arcuatus Pander, 1856, Drepanoistodus aff. amoenus (Lindström, 1955) sensu Löfgren (1994), Paroistodus numarcuatus (Lindström, 1955) and Rossodus aff. manitouensis Repetski & Ethington, 1983. Evaluation of the stratigraphic distribution of the different taxa of brachiopods and euconodonts under consideration of the local geology, suggests that the investigated sample represents a level in the upper part of the Tremadocian (Tr2) part of the Alum Shale Formation. The fauna represents the northernmost occurrence of age diagnostic Early Ordovician (Tremadocian) fossils in Sweden.","PeriodicalId":55094,"journal":{"name":"Gff","volume":"144 1","pages":"24 - 40"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46027075","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：