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Westphalian (stage)
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<h2 id="stratigraphy">Stratigraphy</h2> <p>Since 1935, the Westphalian has been split into four substages, from oldest to youngest: Langsettian (Westphalian A), Duckmantian (Westphalian B), Bolsovian (Westphalian C), and "Asturian" (Westphalian D). These substages are defined by <a href="/facts/Index_fossils/AzdPX12G">guide fossils, or "index fossils</a>," particularly <a href="/facts/Macrofossil/TKBySXyG">plant macrofossils</a>, <a href="/facts/Miospore/dMpDK7hd">miospores</a>, and <a href="/facts/Ammonoidea/cRCH9GVd">ammonoids</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> The Westphalian exhibits distinctive changes in plant diversity, and many plant macrofossil <a href="/facts/Assemblage_Zone/AzdPX12G">assemblage zones</a> have been defined across an area encompassing Europe, <a href="/facts/Turkey/KIYAWAs0">Turkey</a>, and the <a href="/facts/The_Maritimes/edkHavUV">Maritime Provinces</a> of Canada.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p> <h3>Langsettian</h3> <p>The Langsettian, previously known as Westphalian A, is named after the village of <a href="/facts/Langsett/tldX7tzR">Langsett</a> in <a href="/facts/South_Yorkshire/s3bSSRW6">South Yorkshire</a>, England. It marks the base of the Westphalian regional stage, as defined by the ammonoid <i><a href="/facts/Gastrioceras/EcrqoHwA">Gastrioceras subcrenatum</a></i>.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> The base of the Langsettian (and the Westphalian as a whole) has been dated to around 319.9<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> or 319.2<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> Ma. </p><p>The Langsettian corresponds to the <i>Calymmotheca ("Lyginopteris") hoeninghausii</i> assemblage zone.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> Many widespread plant species first appear near the base of the Langsettian, indicating a spike of diversification in tropical <a href="/facts/Coal_forest/GokfxYUU">coal swamp</a> habitats.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> Plant diversity steadily increases through the entire Langsettian, though this may be a result of ecological factors such as the receding coastline.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p> <h3>Duckmantian</h3> <p>The Duckmantian, previously known as Westphalian B, is named after the village of <a href="/facts/Duckmanton/mwxX7F4R">Duckmanton</a> in <a href="/facts/Derbyshire/cWS0T6gV">Derbyshire</a>, England. The base of the Duckmantian is defined by the ammonoid <i><a href="/facts/Anthracoceratites/6AYf9Tmv">Anthracoceratites vaderbeckei</a></i>.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> The boundary between the global Bashkirian and Moscovian stages (~315.2 Ma)<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> corresponds to the mid-late part of the Duckmantian.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a><a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p><p>The lower-middle part of the Duckmantian corresponds to the <i>Lonchopteris rugosa</i> Assemblage-zone, the most diverse plant biozone in the Carboniferous coalfields of Europe. The rising diversity trend of the Langsettian continues into this biozone, with few notable changes in species composition. In the majority of European coalfields, plant diversity reached a plateau around halfway through the Duckmantian. Coal swamps became increasingly unstable in the <i>Paripteris linguaefolia</i> assemblage zone, which begins in the upper part of the Duckmantian.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a><a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> </p> <h3>Bolsovian</h3> <p>The Bolsovian, previously known as Westphalian C, is named after the town of <a href="/facts/Bolsover/nQ0qlCJz">Bolsover</a> in Derbyshire. The base of the Bolsovian is defined by the ammonoid <i><a href="/facts/Donetzoceras/I8eIlf97">Donetzoceras aegiranum</a></i>,<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a> and has an estimated age of around 313.8<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> or 313.7<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a> Ma. </p><p>The <i>Paripteris linguaefolia</i> assemblage zone continues into the Bolsovian, and a decline in plant diversity is apparent across the entirety of Europe.<a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a> In a few coalfields, such as the <a href="/facts/Nord-Pas_de_Calais_Mining_Basin/uDqvIeP4">Nord-Pas-des-Calais basin</a> of northern France, the decline is delayed until the mid-Bolsovian, while in other areas it may begin as early as the late Duckmantian. The overall downward diversity trend is slight, but several notable <a href="/facts/Lycopsid/YPm8zJq1">lycopsid</a> and <a href="/facts/Equisetidae/vQvPSyYj">sphenopsid</a> species disappear from European coal swamps at this time.<a class="footnote-ref" id="fnref:29" href="#fn:29"><sup>29</sup></a> </p> <h3>Westphalian D</h3> <p>Westphalian D is often referred to as the Asturian, named after the <a href="/facts/Asturias/KHVsQe5T">Asturias</a> region of northwest <a href="/facts/Spain/bIyrB8EY">Spain</a>.<a class="footnote-ref" id="fnref:30" href="#fn:30"><sup>30</sup></a> In most of Europe, Westphalian D is distinguished by plant fossils. Asturias is one of the few European regions with enough late Westphalian marine fossils to allow for precise correlations with other marine strata. The proposal to fully implement the name "Asturian" has yet to be ratified, as some stratigraphic difficulties in Spain are not fully resolved.<a class="footnote-ref" id="fnref:31" href="#fn:31"><sup>31</sup></a><a class="footnote-ref" id="fnref:32" href="#fn:32"><sup>32</sup></a> </p><p>The lower part of the Asturian belongs to the <i>Linopteris obliqua</i> assemblage zone<a class="footnote-ref" id="fnref:33" href="#fn:33"><sup>33</sup></a> (sometimes termed the <i>Linopteris bunburii</i> zone).<a class="footnote-ref" id="fnref:34" href="#fn:34"><sup>34</sup></a> This biozone is notably lower in diversity than previous Westphalian biozones. Plant fossils are still common over much of Europe, with <i><a href="/facts/Neuropteris/ALBzlpwv">Neuropteris ovata</a></i> as a particularly abundant species.<a class="footnote-ref" id="fnref:35" href="#fn:35"><sup>35</sup></a> An important ecological turnover occurs about halfway through the Asturian (~309 Ma),<a class="footnote-ref" id="fnref:36" href="#fn:36"><sup>36</sup></a> with the arrival of the <i>Crenulopteris acadica</i> assemblage zone<a class="footnote-ref" id="fnref:37" href="#fn:37"><sup>37</sup></a><a class="footnote-ref" id="fnref:38" href="#fn:38"><sup>38</sup></a><a class="footnote-ref" id="fnref:39" href="#fn:39"><sup>39</sup></a><a class="footnote-ref" id="fnref:40" href="#fn:40"><sup>40</sup></a> (previously known as the <i>Lobatopteris vestita</i> zone).<a class="footnote-ref" id="fnref:41" href="#fn:41"><sup>41</sup></a> Lycopsid fossils become very rare, while <a href="/facts/Marattiaceae/MFo2o9tA">marattialean</a> ferns become abundant in coal swamp deposits.<a class="footnote-ref" id="fnref:42" href="#fn:42"><sup>42</sup></a> Many European coalfields were positioned in a <a href="/facts/Foreland_basin/DWF9lHUL">foreland basin</a> north of the <a href="/facts/Variscan_orogeny/487yDFUj">Variscan orogeny</a>. As mountain-building continued, uplift accelerated in the basin, endangering the survival of coal swamp environments.<a class="footnote-ref" id="fnref:43" href="#fn:43"><sup>43</sup></a><a class="footnote-ref" id="fnref:44" href="#fn:44"><sup>44</sup></a> </p><p>Plant fossils (and coal deposits as a whole) are uncommon in the following "Cantabrian" substage of the Stephanian Stage.<a class="footnote-ref" id="fnref:45" href="#fn:45"><sup>45</sup></a> The end of the Asturian is a topic of strong debate; most estimates place the Westphalian-Stephanian boundary before the start of the Kasimovian global stage (~307 Ma),<a class="footnote-ref" id="fnref:46" href="#fn:46"><sup>46</sup></a><a class="footnote-ref" id="fnref:47" href="#fn:47"><sup>47</sup></a><a class="footnote-ref" id="fnref:48" href="#fn:48"><sup>48</sup></a> whereas a few place the boundary within the Kasimovian.<a class="footnote-ref" id="fnref:49" href="#fn:49"><sup>49</sup></a> U-Pb radiometric dating of <a href="/facts/Tonstein/2BsQkCrS">tonstein</a> beds in Spain estimate that the Asturian lasted from 310.7 to 307.5 Ma, ending just prior to the Kasimovian.<a class="footnote-ref" id="fnref:50" href="#fn:50"><sup>50</sup></a> </p> <h2 id="life">Life</h2> <p>The Westphalian interval is widely recognized for its coal deposits-- rocks that were deposited broadly across regions that were in low paleolatitudes. These deposits, from so-called "coal swamps" have yielded rich assemblages of fossils including spore-bearing and seed-bearing plants, fishes, and tetrapods.<a class="footnote-ref" id="fnref:51" href="#fn:51"><sup>51</sup></a><a class="footnote-ref" id="fnref:52" href="#fn:52"><sup>52</sup></a><a class="footnote-ref" id="fnref:53" href="#fn:53"><sup>53</sup></a> <a href="/facts/Amphibian/r2BleD2W">Amphibians</a> were diverse and dominated some communities. The <a href="/facts/Carboniferous_rainforest_collapse/Vy6pxKrh">collapse of the rainforest ecology</a> between the Moscovian and Kasimovian removed many amphibian species that did not survive as well in the cooler, drier conditions. Reptiles, however prospered due to specific key adaptations and underwent a major evolutionary radiation, in response to the drier climate that led to the rainforest collapse.<a class="footnote-ref" id="fnref:54" href="#fn:54"><sup>54</sup></a><a class="footnote-ref" id="fnref:55" href="#fn:55"><sup>55</sup></a> </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J X. (2023). "International chronostratigraphic chart". www.stratigraphy.org. <a href="https://stratigraphy.org/chart" target="_blank">https://stratigraphy.org/chart</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Opluštil, Stanislav; Laurin, Jiří; Hýlová, Lada; Jirásek, Jakub; Schmitz, Mark; Sivek, Martin (2022-05-01). "Coal-bearing fluvial cycles of the late Paleozoic tropics; astronomical control on sediment supply constrained by high-precision radioisotopic ages, Upper Silesian Basin". Earth-Science Reviews. 228: 103998. Bibcode:2022ESRv..22803998O. doi:10.1016/j.earscirev.2022.103998. ISSN 0012-8252. <a href="https://www.sciencedirect.com/science/article/pii/S0012825222000824" target="_blank">https://www.sciencedirect.com/science/article/pii/S0012825222000824</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J X. (2023). "International chronostratigraphic chart". www.stratigraphy.org. <a href="https://stratigraphy.org/chart" target="_blank">https://stratigraphy.org/chart</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Knight, John A.; Cleal, Christopher J.; Álvarez-Vázquez, Carmen (2023-06-14). "The challenge of relating the Kasimovian to west European chronostratigraphy: a critical review of the Cantabrian and Barruelian substages of the Stephanian Stage". Geological Society, London, Special Publications. 535 (1): 31–71. Bibcode:2023GSLSP.535..189K. doi:10.1144/SP535-2022-189. ISSN 0305-8719. <a href="https://doi.org/10.1144%2FSP535-2022-189" target="_blank">https://doi.org/10.1144%2FSP535-2022-189</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J X. (2023). "International chronostratigraphic chart". www.stratigraphy.org. <a href="https://stratigraphy.org/chart" target="_blank">https://stratigraphy.org/chart</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Aretz, M.; Herbig, H.G.; Wang, X.D.; Gradstein, F.M.; Agterberg, F.P.; Ogg, J.G. (2020), "The Carboniferous Period", Geologic Time Scale 2020, Elsevier, pp. 811–874, doi:10.1016/b978-0-12-824360-2.00023-1, ISBN 978-0-12-824360-2, retrieved 2023-10-09 <a href="978-0-12-824360-2" target="_blank">978-0-12-824360-2</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Opluštil, Stanislav; Schmitz, Mark; Cleal, Christopher J.; Martínek, Karel (2016). "A review of the Middle–Late Pennsylvanian west European regional substages and floral biozones, and their correlation to the Geological Time Scale based on new U–Pb ages". Earth-Science Reviews. 154: 301–335. Bibcode:2016ESRv..154..301O. doi:10.1016/j.earscirev.2016.01.004. <a href="https://linkinghub.elsevier.com/retrieve/pii/S0012825216300046" target="_blank">https://linkinghub.elsevier.com/retrieve/pii/S0012825216300046</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Waters, C.N. (2011-07-13), Waters, C.N.; Somerville, I.D.; Jones, N.S.; Cleal, C.J. (eds.), "Definitions of chronostratigraphic subdivisions: geochronology and event stratigraphy", A Revised Correlation of Carboniferous Rocks in the British Isles (First ed.), The Geological Society of London, pp. 3–10, doi:10.1144/sr26.2, ISBN 978-1-86239-694-4, retrieved 2023-10-09 <a href="978-1-86239-694-4" target="_blank">978-1-86239-694-4</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Waters, C.N.; Somerville, I.D.; Stephenson, M.H.; Cleal, C.J.; Long, S.L. (2011-07-13), Waters, C.N.; Somerville, I.D.; Jones, N.S.; Cleal, C.J. (eds.), "Biostratigraphy", A Revised Correlation of Carboniferous Rocks in the British Isles (First ed.), The Geological Society of London, pp. 11–22, doi:10.1144/sr26.3, ISBN 978-1-86239-694-4, retrieved 2023-10-09 <a href="978-1-86239-694-4" target="_blank">978-1-86239-694-4</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Aretz, M.; Herbig, H.G.; Wang, X.D.; Gradstein, F.M.; Agterberg, F.P.; Ogg, J.G. (2020), "The Carboniferous Period", Geologic Time Scale 2020, Elsevier, pp. 811–874, doi:10.1016/b978-0-12-824360-2.00023-1, ISBN 978-0-12-824360-2, retrieved 2023-10-09 <a href="978-0-12-824360-2" target="_blank">978-0-12-824360-2</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Opluštil, Stanislav; Cleal, Christopher J.; Wang, Jun; Wan, Mingli (2022). "Carboniferous macrofloral biostratigraphy: an overview". Geological Society, London, Special Publications. 512 (1): 813–863. Bibcode:2022GSLSP.512..813O. doi:10.1144/SP512-2020-97. ISSN 0305-8719. <a href="https://www.lyellcollection.org/doi/10.1144/SP512-2020-97" target="_blank">https://www.lyellcollection.org/doi/10.1144/SP512-2020-97</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Waters, C.N. (2011-07-13), Waters, C.N.; Somerville, I.D.; Jones, N.S.; Cleal, C.J. (eds.), "Definitions of chronostratigraphic subdivisions: geochronology and event stratigraphy", A Revised Correlation of Carboniferous Rocks in the British Isles (First ed.), The Geological Society of London, pp. 3–10, doi:10.1144/sr26.2, ISBN 978-1-86239-694-4, retrieved 2023-10-09 <a href="978-1-86239-694-4" target="_blank">978-1-86239-694-4</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Pointon, Michael A.; Chew, David M.; Ovtcharova, Maria; Sevastopulo, George D.; Crowley, Quentin G. (2012). "New high-precision U–Pb dates from western European Carboniferous tuffs; implications for time scale calibration, the periodicity of late Carboniferous cycles and stratigraphical correlation". Journal of the Geological Society. 169 (6): 713–721. Bibcode:2012JGSoc.169..713P. doi:10.1144/jgs2011-092. hdl:2262/79149. ISSN 0016-7649. <a href="https://www.lyellcollection.org/doi/10.1144/jgs2011-092" target="_blank">https://www.lyellcollection.org/doi/10.1144/jgs2011-092</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Opluštil, Stanislav; Laurin, Jiří; Hýlová, Lada; Jirásek, Jakub; Schmitz, Mark; Sivek, Martin (2022-05-01). "Coal-bearing fluvial cycles of the late Paleozoic tropics; astronomical control on sediment supply constrained by high-precision radioisotopic ages, Upper Silesian Basin". Earth-Science Reviews. 228: 103998. Bibcode:2022ESRv..22803998O. doi:10.1016/j.earscirev.2022.103998. ISSN 0012-8252. <a href="https://www.sciencedirect.com/science/article/pii/S0012825222000824" target="_blank">https://www.sciencedirect.com/science/article/pii/S0012825222000824</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Opluštil, Stanislav; Cleal, Christopher J.; Wang, Jun; Wan, Mingli (2022). "Carboniferous macrofloral biostratigraphy: an overview". Geological Society, London, Special Publications. 512 (1): 813–863. Bibcode:2022GSLSP.512..813O. doi:10.1144/SP512-2020-97. ISSN 0305-8719. <a href="https://www.lyellcollection.org/doi/10.1144/SP512-2020-97" target="_blank">https://www.lyellcollection.org/doi/10.1144/SP512-2020-97</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Opluštil, Stanislav; Cleal, Christopher J.; Wang, Jun; Wan, Mingli (2022). "Carboniferous macrofloral biostratigraphy: an overview". Geological Society, London, Special Publications. 512 (1): 813–863. Bibcode:2022GSLSP.512..813O. doi:10.1144/SP512-2020-97. ISSN 0305-8719. <a href="https://www.lyellcollection.org/doi/10.1144/SP512-2020-97" target="_blank">https://www.lyellcollection.org/doi/10.1144/SP512-2020-97</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Molina-Solís, Azucena; Cleal, Christopher J.; Capel, Eliott; Cascales-Miñana, Borja (2023). "Vegetation dynamics in the Early–Middle Pennsylvanian coal swamps of the Nord-Pas-de-Calais Coalfield, France". Palaeoworld. 33 (2): 328–340. doi:10.1016/j.palwor.2023.04.005. <a href="https://linkinghub.elsevier.com/retrieve/pii/S1871174X2300046X" target="_blank">https://linkinghub.elsevier.com/retrieve/pii/S1871174X2300046X</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Opluštil, Stanislav; Cleal, Christopher J.; Wang, Jun; Wan, Mingli (2022). "Carboniferous macrofloral biostratigraphy: an overview". Geological Society, London, Special Publications. 512 (1): 813–863. Bibcode:2022GSLSP.512..813O. doi:10.1144/SP512-2020-97. ISSN 0305-8719. <a href="https://www.lyellcollection.org/doi/10.1144/SP512-2020-97" target="_blank">https://www.lyellcollection.org/doi/10.1144/SP512-2020-97</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Waters, C.N. (2011-07-13), Waters, C.N.; Somerville, I.D.; Jones, N.S.; Cleal, C.J. (eds.), "Definitions of chronostratigraphic subdivisions: geochronology and event stratigraphy", A Revised Correlation of Carboniferous Rocks in the British Isles (First ed.), The Geological Society of London, pp. 3–10, doi:10.1144/sr26.2, ISBN 978-1-86239-694-4, retrieved 2023-10-09 <a href="978-1-86239-694-4" target="_blank">978-1-86239-694-4</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Aretz, M.; Herbig, H.G.; Wang, X.D.; Gradstein, F.M.; Agterberg, F.P.; Ogg, J.G. 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