IF 1 4区地球科学

Gff Pub Date : 2020-01-24 DOI: 10.1080/11035897.2019.1701547

A. Holmqvist, C. Alwmark, H. Dypvik, O. Nilsen

引用次数: 0

New data on the problematic mollusc Jinonicella from the early Silurian of east Siberia 东西伯利亚志留纪早期有问题的软体动物Jinonicella的新数据

IF 1 4区地球科学

Gff Pub Date : 2020-01-24 DOI: 10.1080/11035897.2019.1708451

A. Gubanov, J. R. Ebbestad, P. Männik, O. Bogolepova

引用次数: 1

The lower Ovetian Stage (lower Cambrian Stage 3) trilobite zonation in Spain and correlation with West Gondwana 西班牙下奥维梯世(下寒武统第三期)三叶虫分带及其与西冈瓦纳的对比

IF 1 4区地球科学

Gff Pub Date : 2020-01-24 DOI: 10.1080/11035897.2019.1701548

E. Liñán, J. Gámez Vintaned, T. Palacios, R. Gozalo

引用次数: 3

The δ13C chemostratigraphy of Ordovician global stage stratotypes: geochemical data from the Floian and Sandbian GSSPs in Sweden 奥陶系全球层型的δ13C化学地层学:来自瑞典弗洛ian和Sandbian gssp的地球化学数据

IF 1 4区地球科学

Gff Pub Date : 2020-01-02 DOI: 10.1080/11035897.2019.1631883

S. M. Bergström, B. Schmitz, F. Terfelt, M. Eriksson, P. Ahlberg

{"title":"The δ13C chemostratigraphy of Ordovician global stage stratotypes: geochemical data from the Floian and Sandbian GSSPs in Sweden","authors":"S. M. Bergström, B. Schmitz, F. Terfelt, M. Eriksson, P. Ahlberg","doi":"10.1080/11035897.2019.1631883","DOIUrl":"https://doi.org/10.1080/11035897.2019.1631883","url":null,"abstract":"ABSTRACT The δ13C chemostratigraphy of five of the seven Ordovician global stages has been published previously but no such data have been available from the Floian GSSP and most of the Sandbian GSSP in Sweden. This lack of information has now been remedied by isotope data obtained from series of closely spaced shale samples collected from the Floian stratotype at Diabasbrottet in Västergötland and the Sandbian stratotype at Fågelsång in Scania. Although the bases of these stages cannot be precisely tied to levels of conspicuous δ13C excursions, that of the Floian Stage, which is marked by the appearance of the graptolite Tetragraptus approximatus, is between the closely spaced excursions named LTNICE and BFICE. The base of the Sandbian Stage, which is defined as the appearance level of the graptolite Nemagraptus gracilis, is just below a negative excursion previously known as the “Upper Kukruse Low”, which is nowadays known as the LSNICE. The relations between chemostratigraphy and graptolite and conodont biostratigraphy in the Swedish GSSPs and some coeval key sections in Baltoscandia, China, and America are briefly discussed. It is concluded that the data at hand indicate that there is good regional agreement in these relations.","PeriodicalId":55094,"journal":{"name":"Gff","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/11035897.2019.1631883","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48848432","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: 5

The “intraorogenic” Svecofennian Herräng mafic dyke swarm in east-central Sweden: age, geochemistry and tectonic significance 瑞典中东部的“造山期内”Svecofennian-Herräng镁铁质岩脉群：年龄、地球化学和构造意义

IF 1 4区地球科学

Gff Pub Date : 2020-01-02 DOI: 10.1080/11035897.2019.1708450

Å. Johansson, A. Karlsson

{"title":"The “intraorogenic” Svecofennian Herräng mafic dyke swarm in east-central Sweden: age, geochemistry and tectonic significance","authors":"Å. Johansson, A. Karlsson","doi":"10.1080/11035897.2019.1708450","DOIUrl":"https://doi.org/10.1080/11035897.2019.1708450","url":null,"abstract":"ABSTRACT The Herräng mafic dykes form an E-W-trending dyke swarm within the Bergslagen lithotectonic unit of the Svecofennian orogen in east-central Sweden. They intrude the Svecofennian supracrustal rocks and early-orogenic granitoids, but are themselves cut by late Svecofennian pegmatites, and have undergone Svecofennian amphibolite-facies metamorphism, leading to their classification as “intraorogenic” Svecofennian dykes. They can be assigned an age between 1870 and 1850 Ma, with metamorphism of the dykes dated at 1848 ± 13 Ma by U-Pb in titanite. Their current mineralogy is dominated by metamorphic plagioclase and amphibole, with variable amounts of quartz and biotite, and minor to accessory titanite, apatite, epidote, pyrite, magnetite, ilmenite and zircon. Textures range from massive to strongly foliated. Twenty samples of dyke rocks from three subareas in the Roslagen region, including the Herräng type area, range in composition from basaltic to andesitic with 47 to 60 wt% SiO2, broadly similar to the Dannemora dykes and the Avesta-Östhammar gabbros and diorites. Initial 87Sr/86Sr ratios (at 1870 Ma) varies between 0.7026 and 0.7038, corresponding to initial εSr between +5 and +21, and initial εNd between −0.4 and +1.3, suggesting a slightly enriched to mildly depleted mantle source, similar to other Svecofennian mafic rocks. The dykes dominantly show a calc-alkaline volcanic arc signature related to subduction. They formed during an extensional episode, possibly related to incipient back-arc spreading or subduction roll-back following the main early-orogenic subduction-related Svecofennian magmatism, but penecontemporaneous with amphibolite-facies metamorphism in the area.","PeriodicalId":55094,"journal":{"name":"Gff","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/11035897.2019.1708450","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45744086","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

Biogenic and abiogenic injuries in a Carboniferous Bellerophon (Gastropoda) from the Isle of Man, United Kingdom 英国马恩岛石炭纪腹足类Bellerophon的生物与非生物伤害

IF 1 4区地球科学

Gff Pub Date : 2020-01-02 DOI: 10.1080/11035897.2019.1621376

J. S. Peel

引用次数: 2

Vertebrate remains and conodonts in the upper Silurian Hamra and Sundre formations of Gotland, Sweden 瑞典哥特兰岛上志留纪Hamra和Sundre地层的脊椎动物遗骸和牙形刺

IF 1 4区地球科学

Gff Pub Date : 2020-01-02 DOI: 10.1080/11035897.2019.1655790

Oskar Bremer, E. Jarochowska, T. Märss

{"title":"Vertebrate remains and conodonts in the upper Silurian Hamra and Sundre formations of Gotland, Sweden","authors":"Oskar Bremer, E. Jarochowska, T. Märss","doi":"10.1080/11035897.2019.1655790","DOIUrl":"https://doi.org/10.1080/11035897.2019.1655790","url":null,"abstract":"ABSTRACT A long history of geological research on the island of Gotland, Sweden, has resulted in a detailed biostratigraphy based on conodonts for the Gotland sedimentary succession, but the relation between the Hamra and Sundre formations, the youngest strata on southern Gotland, has remained poorly resolved. These formations have also remained relatively poorly described in terms of vertebrates compared to other parts of the succession. A survey of museum collections and newly sampled material reveal that the taxonomical compositions and richness of vertebrate faunas remain similar compared to the underlying Burgsvik Sandstone and Oolite members. However, the relative abundance of the respective groups changes: Paralogania ludlowiensis and rare osteostracan remains of Tahulaspis sp. only occur in samples from the lower Hamra Formation, while Thelodus sculptilis becomes more common in samples from Sundre Formation. Conodont and isotope data give support to previous suggestions that the Hamra and Sundre formations may be largely isochronous, and it is possible that the observed differences in vertebrate faunas reflect changes in depositional setting. This interval on Gotland has been suggested to represent a hiatus in the East Baltic sections, where younger strata show an increased importance of acanthodians in the vertebrate faunas. Gotland could therefore give insights into the early stages of this diversification of gnathostomes during late Silurian times. However, this has to be done in combination with data from other areas, as well as with a review and revision of the scale-based taxonomy of Silurian acanthodians from the Baltic Basin.","PeriodicalId":55094,"journal":{"name":"Gff","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/11035897.2019.1655790","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59720660","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: 4

Graptolite biostratigraphy of the Ordovician Almelund and Sularp Shale formations of the Fågelsång-3 drill core, Scania, Sweden 瑞典f<s:1> gels<s:1> ng-3岩心奥陶系Almelund组和Sularp组笔石生物地层学

IF 1 4区地球科学

Gff Pub Date : 2020-01-02 DOI: 10.1080/11035897.2019.1621370

J. Maletz, P. Ahlberg

引用次数: 6

A late Caledonian tectono-thermal event in the Gaissa Nappe Complex, Arctic Norway: evidence from fine-fraction K‒Ar dating and illite crystallinity from the Digermulen Peninsula 挪威北极盖萨-纳佩杂岩中的一次晚喀里多尼亚构造热事件：来自Digermulen半岛细粒K-Ar定年和伊利石结晶度的证据

IF 1 4区地球科学

Gff Pub Date : 2019-10-02 DOI: 10.1080/11035897.2019.1583685

G. Meinhold, K. Wemmer, Anette E. S. Högström, J. R. Ebbestad, S. Jensen, T. Palacios, M. Høyberget, Heda Agić, W. Taylor

{"title":"A late Caledonian tectono-thermal event in the Gaissa Nappe Complex, Arctic Norway: evidence from fine-fraction K‒Ar dating and illite crystallinity from the Digermulen Peninsula","authors":"G. Meinhold, K. Wemmer, Anette E. S. Högström, J. R. Ebbestad, S. Jensen, T. Palacios, M. Høyberget, Heda Agić, W. Taylor","doi":"10.1080/11035897.2019.1583685","DOIUrl":"https://doi.org/10.1080/11035897.2019.1583685","url":null,"abstract":"ABSTRACT Fine-fraction K‒Ar dating and illite crystallinity determination were applied on a peculiar pale olive green shale sample from the upper Ediacaran Indreelva Member (Stáhpogieddi Formation, Vestertana Group, Gaissa Nappe Complex) of the Digermulen Peninsula in Finnmark, Arctic Norway, to constrain the age and metamorphic conditions of tectono-thermal overprint. The <2 and <0.2 µm grain-size fractions are almost purely illite and yielded an illite crystallinity (expressed as the Kübler index) of 0.215 Δ° 2θ and 0.228 ∆° 2θ and K‒Ar ages of 403.9 ± 4.2 and 391.5 ± 4.0 Ma, respectively. The K‒Ar ages are interpreted to present late-stage thermal overprint under low epizonal conditions along a localised shear zone, likely post-dating the peak of metamorphism and cleavage generation on the Digermulen Peninsula. Thus, a later tectono-metamorphic event related to the late stage of the Scandian orogeny is locally recorded in the Gaissa Nappe Complex of the Caledonides of Finnmark. This late Scandian event was probably caused by orogenic extensional collapse and appears to have extended at least into Mid-Devonian time.","PeriodicalId":55094,"journal":{"name":"Gff","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/11035897.2019.1583685","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48926686","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: 8

Upper Cretaceous rhyolitic ash beds from the Novaya Sibir Island (New Siberian Islands) Novaya Sibir岛（新西伯利亚群岛）的上白垩纪流纹岩灰层

IF 1 4区地球科学

Gff Pub Date : 2019-09-30 DOI: 10.1080/11035897.2019.1641548

V. Kostyleva, E. Shchepetova, A. Kotelnikov

引用次数: 3

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