New U–Pb zircon ages of the Sandbian (Upper Ordovician) “Big K-bentonite” in Baltoscandia (Estonia and Sweden) by LA-ICPMS

Bauert, Heikki; Isozaki, Yukio; Holmer, Lars E.; Aoki, Kazumasa; Sakata, Shuhei; Hirata, Takafumi

doi:10.1080/11035897.2013.862854

Cited by 15 publications

(17 citation statements)

References 30 publications

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“…; Bauert et al . ), that have been often used for intercontinental correlation. As some outcrops of these tuff beds attain several metres in thickness, large‐scale magmatism was imagined in analogy with LIPs; nonetheless, this is not the case.…”

Section: Differencesmentioning

confidence: 99%

“…A prominent signature of magmatism is recorded in the Late-Ordovician volcanic ash beds found in shelf carbonates in Baltica and Laurentia, for example the Kinnekulle, Deikie and Millbrig K-bentonite beds (e.g. Huff et al 2010;Bauert et al 2014), that have been often used for intercontinental correlation. As some outcrops of these tuff beds attain several metres in thickness, large-scale magmatism was Fig.…”

Section: Volcanism/superplumementioning

confidence: 99%

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The Hirnantian (Late Ordovician) and end-Guadalupian (Middle Permian) mass-extinction events compared

Isozaki

Servais

2018

LET

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The so‐called Big Five mass extinctions of the Phanerozoic include two prominent Palaeozoic episodes: the end‐Ordovician and end‐Permian events, both with large biodiversity loss. We consider that the end‐Ordovician (Hirnantian) extinction could be best compared to the Middle Permian end‐Guadalupian (=Capitanian) extinction, rather than to the end‐Permian (Permo‐Triassic boundary; PTB) extinction. The end‐Guadalupian extinction, ca. 8 Myr before the PTB extinction, occurred as an independent episode under extremely unique global setting with the lowest sea level and lowest Sr isotopic ratios in seawater of the Phanerozoic. Multiple similarities exist between the end‐Ordovician (Hirnantian) and the end‐Guadalupian (Capitanian) events, such as the preferential elimination of sessile biota in the tropics, a global sea‐level drop and secular changes in seawater C and Sr isotope ratios, occurring under global cooling. The limited development of land vegetation suggests that the Ordovician extinction was restricted solely to the marine realm, with no prominent damages on land, and no large igneous province (LIP) recognized in the Ordovician. The comparison indicates that the two extinctions of the Hirnantian and of the Capitanian have been essentially triggered by similar causes/processes; nonetheless, biotic responses were different, owing to the more oxygenated status of surface environments in the Permian after the mid‐Palaeozoic terrestrialization.

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Section: Differencesmentioning

confidence: 99%

Section: Volcanism/superplumementioning

confidence: 99%

The Hirnantian (Late Ordovician) and end-Guadalupian (Middle Permian) mass-extinction events compared

Isozaki

Servais

2018

LET

Self Cite

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“…3). Additionally, several bentonite beds within the succession provide radiometric age constraints (Sell et al 2013;Bauert et al 2014).…”

Section: Methodsmentioning

confidence: 99%

“…3). The type locality of this distinctive 1.8-m-thick bentonite bed is located on the eastern slope of Kinnekulle (Bauert et al 2014), in south central Sweden (Fig. 1).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…1). Zircons from the upper part of this bed were dated by 206 Pb/ 238 U radiometric methods to c. 454 Ma, which corresponds to the late Sandbian (Bauert et al 2014). This age is consistent with 206 Pb/ 238 U dating of the equivalent bentonite bed across the Baltic Sea (Bauert et al 2014), more specifically, high-precision dating of the bentonite bed on the island of Bornholm, Denmark, obtained an age of 454.41 ± 0.17 (Sell et al 2013).…”

Section: Geological Backgroundmentioning

confidence: 99%

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Baltica cradle of early land plants? Oldest record of trilete spores and diverse cryptospore assemblages; evidence from Ordovician successions of Sweden

Rubinstein

Vajda

2019

GFF

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The origin of land plants is one of the most important evolutionary events in Earth's history. The mode and timing of the terrestrialization of plants remains debated and previous data indicate Gondwana to be the center of land-plant radiation at~470-460 Ma. Here we present the oldest occurrences of trilete spores, probably the earliest traces of vascular land plants yet recorded. The spores occur in Ordovician, Sandbian (455 million years old) successions in central Sweden, once part of the paleocontinent Baltica. These strata are independently dated by marine microfossils (conodonts) and 206 Pb/ 238 U dating of volcanic ash deposits. Our discovery extends the record of trilete spores globally by~8 million years, and for Baltica by~25 million years. Additionally, cryptospore assemblages are identified revealing a diverse and stable mid-Ordovician (Darriwilian:~460 Ma) vegetation of free-sporing plants. The formation of regolith substrates on land as a consequence of permanent plant cover must in turn have affected the marine biota. We link these early land plant spore occurrences to the extensive, nutrient-rich volcanic ash deposits and propose Baltica as the possible original region of the radiation of early land plants. ARTICLE HISTORY

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The Ordovician Period

Goldman¹,

Sadler²,

Leslie³

et al. 2020

Geologic Time Scale 2020

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New U–Pb zircon ages of the Sandbian (Upper Ordovician) “Big K-bentonite” in Baltoscandia (Estonia and Sweden) by LA-ICPMS

Cited by 15 publications

References 30 publications

The Hirnantian (Late Ordovician) and end-Guadalupian (Middle Permian) mass-extinction events compared

The Hirnantian (Late Ordovician) and end-Guadalupian (Middle Permian) mass-extinction events compared

Baltica cradle of early land plants? Oldest record of trilete spores and diverse cryptospore assemblages; evidence from Ordovician successions of Sweden

The Ordovician Period

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