Geology

doi: 10.1130/G32191.1 2011;39;739-742Geology

 Xiaoming Zhao, Haishui Jiang, Chunbo Yan, Zhijun Niu, Jing Chen, Hao Yang and Yongbiao WangHaijun Song, Paul B. Wignall, Zhong-Qiang Chen, Jinnan Tong, David P.G. Bond, Xulong Lai, mass extinctionRecovery tempo and pattern of marine ecosystems after the end-Permian  

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ABSTRACTHigh-resolution sampling of more than 10,000 microfossils

from seven Late Permian−Middle Triassic paleoequatorial sections in south China refutes claims for a 5 m.y. recovery delay after the end-Permian mass extinction. We show that level-bottom seafl oor diversity began to recover in the early Smithian, little more than 1 m.y. after the mass extinction, while recovery of reef-building metazoans began 4 m.y. later, in the Anisian. A further mass extinc-tion in the late Smithian, identifi ed in the pelagic fossil record, is weakly manifest as a temporary pause in diversifi cation among ben-thic communities. In the Early Triassic of south China, the offshore diversity increase began before then, in shallower settings. The recovery from the end-Permian mass extinction in south China was therefore signifi cantly more rapid and environmentally more com-plex than hitherto known.

INTRODUCTIONThe end-Permian mass extinction was the greatest crisis of the Pha-

nerozoic and has been the focus of much recent research, but the nature and timing of the subsequent radiation are equally intriguing. The Early Triassic has been traditionally viewed as an unusual time marked by sup-pressed origination rates and low diversity, i.e., a failed recovery interval that persisted until the Middle Triassic (Hallam, 1991; Schubert and Bot-tjer, 1995; Erwin, 1998; Payne et al., 2006a; Galfetti et al., 2008). Expla-nations have included either the prolongation of the stresses that caused the end-Permian extinction (Hallam, 1991; Payne et al., 2004), the mag-nitude of the extinction (Erwin, 2001), or the effects of further extinction crises in the Early Triassic (Orchard, 2007; Stanley, 2009). More recently, this orthodoxy has been challenged with evidence from ammonoids and conodonts that show a rapid rebound from the mass extinction, punctu-ated by additional biotic crises at the end of the Griesbachian, Smith-ian, and Spathian subtages of the Early Triassic (Brayard et al., 2009; Stanley, 2009). Stanley (2009, p. 15,266) contested that the Early Trias-sic fauna were radiating between times of crisis, and that groups with generally high origination rates (i.e., ammonoids and conodonts) provide the best record of these recovery intervals. This assertion is supported by the pterinopectinid (fl at clams) fossil record, such as that of Claraia, which, uniquely for a bivalve group, shows very high origination and/or extinction rates both before and after the end-Permian extinction (Yin, 1985). Benthic communities of bivalves and gastropods of modest diver-sity are also occasionally encountered in the late Griesbachian, the fi rst substage of the Early Triassic (Wignall and Twitchett, 2002; Hautmann et al., 2011). However, it has yet to be shown that modest recovery is seen generally among Early Triassic benthic communities. The impact of the three Early Triassic extinction crises on these communities has not been demonstrated, with the exception of the well-known end-Smithian event (Hallam and Wignall, 1997; Wignall, 2008).

METHODS AND DATAThe trajectory of Early–Middle Triassic recovery in level-bottom

communities is poorly documented, and taxonomic diversity trends are not well known. To examine these patterns, we have studied the occur-rence of marine microfossil groups (foraminifers, calcareous algae, and the calcimicrobe Tubiphytes) at high resolution from seven Late Permian−Middle Triassic sections in south China: three sections from the Yangtze Block and four sections from Nanpanjiang Basin, where offshore to car-bonate platform facies are well developed (Lehrmann et al., 2003; Fig. 1; see the GSA Data Repository1). Correlation is based upon a conodont biostratigraphic study.

We identifi ed 10,276 individual microfossils belonging to 84 gen-era and 136 species in 1780 thin sections (see the Data Repository). This revealed that all calcareous algae, Tubiphytes, and most foraminifers dis-appeared in the latest Permian. Microfossil diversity was then very low throughout the succeeding Induan Stage in all sections (Figs. 2 and 3). Cyanobacteria dominated benthic carbonate production in the immedi-

Geology, August 2011; v. 39; no. 8; p. 739–742; doi:10.1130/G32191.1; 3 fi gures; Data Repository item 2011224.© 2011 Geological Society of America. For permission to copy, contact Copyright Permissions, GSA, or editing@geosociety.org.

*E-mails: p.wignall@see.leeds.ac.uk; jntong@cug.edu.cn.

Recovery tempo and pattern of marine ecosystems after the end-Permian mass extinctionHaijun Song1,2, Paul B. Wignall2*, Zhong-Qiang Chen3, Jinnan Tong1*, David P.G. Bond2, Xulong Lai1, Xiaoming Zhao4, Haishui Jiang1, Chunbo Yan1, Zhijun Niu4, Jing Chen1, Hao Yang1, and Yongbiao Wang1

1 State Key Laboratory of Biogeology and Environmental Geology of Ministry of Education, China University of Geosciences, Wuhan 430074, China

2School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK 3School of Earth and Geographical Sciences, University of Western Australia, Perth, WA 6009, Australia4Wuhan Institute of Geology and Mineral Resources, Wuhan 430205, China

1GSA Data Repository item 2011224, Table DR1 (list of microfossil names) and Table DR2 (primary microfossil data), is available online at www.geosociety.org/pubs/ft2011.htm, or on request from editing@geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.

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Figure 1. Early Triassic paleogeographic map of south China (modi-fi ed from Lehrmann et al., 2006). Plots show sampled sections: Chaohu, Wufeng, and Shangsi in Yangze Block provide Early Trias-sic strata; Dajiang (platform margin), Qingyan (basin margin), and Bianyang (basin) sections in Nanpanjiang Basin expose Late Perm-ian to Middle Triassic strata. Guandao (basin margin) section in Nan-panjiang Basin exposes Early to Late Triassic strata.

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740 GEOLOGY, August 2011

ate aftermath of the end-Permian mass extinction, when microbial reefs were common (e.g., Baud et al., 2007). Calcareous algae are absent from Induan strata, except for rare, poorly preserved records from boreal lati-tudes (Wignall et al., 1998). Our south China data reveal that low-latitude calcareous algal productivity (together with Tubiphytes) was reestablished in the Smithian, with low abundance, but moderately high diversity popu-lations (Fig. 2) reappearing in offshore locations. Foraminifers also reap-peared at this time in diverse platform settings (Figs. 2 and 3). This is considerably earlier than hitherto reported for this group and contrasts with the reports from the Great Bank of Guizhou, a carbonate platform in south China, where recovery began in the Anisian (Payne et al., 2006a). Origination rates of foraminifer species are especially high in the Smithian Substage, but values return to zero in the early Spathian before increasing slightly. There is no perceptible change in origination or extinction rates across the Spathian-Anisian boundary (Fig. 3). After the end-Permian crisis, extinction rates remain low throughout the Early–Middle Trias-sic interval, with little evidence for any extinction peaks except perhaps a minor one at the end of the Smithian (Fig. 3). A minor early Spathian

75Foraminife sr

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AnisianSpathianGr. Di. Sm.

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Induan Olenekian

Figure 2. Microfossil stratigraphic distributions during Permian−Triassic interval in south China: 1357 individuals from Shangsi section; 26 individuals from Chaohu section; 107 individuals from Wufeng section; 1037 individuals from Qingyan section; 6058 individuals from Guandao section; 328 individuals from Bianyang section; and 1363 individuals from Dajiang section. For a list of microfossil names, see Table DR1 (see footnote 1). Primary microfossil data in each section are shown in Table DR2. Foraminifers from Dajiang section were de-scribed in Song et al. (2009). Absolute age constraints are from Mundil et al. (2004), Lehrmann et al. (2006), Ovtcharova et al. (2006), and Galfetti et al. (2007). Gr.—Griesbachian; Di.—Dienerian; Sm.—Smithian.

Figure 3. Diversity trends in Late Permian–Middle Triassic interval showing total diversity consisting of foraminifer species present plus range through species, and extinction and origination rates (disappearing or new taxa per 0.5 m.y.). Following end-Permian mass extinction, there is an ~1 m.y. diversity low point, followed by radiation starting in Olenekian that reached ~40 species diversity plateau in Middle Triassic. Gr.—Griesbachian; Di.—Dienerian; Sm.—Smithian.

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decline in diversity values is attributable to the decrease of origination rates rather than an increase of extinction rates.

DISCUSSIONMicrofossil data from south China show that benthic recovery

began in the Early Triassic, within 1 m.y. of the end-Permian mass extinction, and thus do not support the idea of a long-delayed recov-ery. This conclusion is partly a corollary of recent dramatic improve-ments in radiometric dating of this interval; the dating has shown that the Early Triassic was only ~5 m.y. long, rather than the 7–8 m.y. of ear-lier estimates, and that much of this time is represented by the Spathian Substage (Ovtcharova et al., 2006; Galfetti et al., 2007). However, the radiation is seen to begin with an impressive increase in origination rates at the start of the Smithian Substage, and not the Anisian Stage, as previ-ously suggested (e.g., Schubert and Bottjer, 1995; Erwin, 1998; Payne et al., 2006a, 2006b; Galfetti et al., 2008). This benthic microfossil record does not tally with ammonoid and conodont records that show rapid origination rates in the immediate aftermath of the end-Permian extinc-tion (Orchard, 2007; Brayard et al., 2009; Stanley, 2009). The Induan thus was a time of rapid diversifi cation of pelagic communities, while benthic ones remained moribund. The benthic record does not provide evidence for three Early Triassic extinction events seen in the pelagic record; only the end-Smithian event may be present, although it is seen only as a decline in origination rates, not as an increase in extinction rates. Stanley’s (2009, p. 15,265) prediction that “these [pelagic crisis] events must have been aspects of global mass extinctions for marine life in general” (our brackets) is therefore not supported by our data. How-ever, Brayard et al.’s (2009, p. 1120) quandary of how “cephalopods fl ourish in the presumably unstable and harsh conditions prevailing [in the Early Triassic]” (our brackets) may still be apposite, but only during the brief Induan Stage. In the subsequent Olenekian Stage, both pelagic and benthic communities radiated rapidly, suggesting that the marine habitats were presumably normal. The oceanic redox record for this interval indicates poor ventilation during the Induan, and improvement in the Olenekian (Wignall et al., 2010). However, a subsequent anoxic event in the late Spathian did not arrest the benthic recovery.

If ecological-scale processes controlled postextinction radiation, then higher trophic levels are predicted to recover later than the lower trophic levels (Erwin, 2001; Solé et al., 2002). However, the combination of our south China microfossil study and ammonoid and conodont data shows that trophic level fails to predict recovery rates. Instead, Stanley’s (2008, 2009) observation that intrinsic evolutionary rates of the higher taxa are generally better guides to postextinction evolutionary rates is better sup-ported by the data. Only the evolution of metazoan reef communities still accords with the traditional view of a prolonged Early Triassic failure to recover. Metazoan reef ecosystems did not reappear until the Anisian, when they were composed of Tubiphytes, sponges, and corals (Stanley, 1988). Tubiphytes, a probable calcimicrobial microfossil, appears in level-bottom communities in the Smithian of south China (Fig. 2), but it forms reefs only in early Anisian strata of the Nanpanjiang Basin (Payne et al., 2006b). More diverse reefs containing scleractinian corals and calcareous sponges appeared in the middle Anisian (Flügel, 2002).

Our observation that the onset of benthic radiation began in rela-tively deeper water environments is a new discovery, and it contrasts with the pattern seen in higher latitude sites, where trace fossil diversity rapidly recovers in nearshore settings within 1 m.y. of the end-Permian mass extinction (Wignall et al., 1998; Wignall and Twitchett, 2002; Zonneveld et al., 2010). Thus, in south China, calcareous algae and Tubi-phytes fi rst appear in offshore settings in the Smithian, then in nearshore settings in the Spathian, and fi nally in carbonate platforms in the early Anisian. The Olenekian radiation pattern indicates a progression from offshore to platform locations, and contrasts with the general onshore to

offshore pattern noted for marine communities generally, and especially in the Paleozoic (Jablonski et al., 1983). Apparently, Early Triassic ben-thic recovery trajectories differed in both environmental style and timing in different regions.

The recovery from the end-Permian mass extinction was thus governed by the intrinsic evolutionary rates of the surviving taxa and the impact of subsequent extinction events, particularly around the Smithian-Spathian boundary. Recovery began immediately among the groups with the highest background evolutionary rates, i.e., ammonoids and conodonts. Groups such as foraminifers with more modest rates recovered more slowly. This indicates that there was no long-term pro-longation of the end-Permian mass extinction stresses. There is a signal of regional and environmental selectivity to the recovery among benthic taxa: high-latitude, shallow-water communities were among the fi rst to achieve appreciable diversity, and offshore microfossils recovered per-ceptibly faster than those nearer shore in south China.

CONCLUSIONBenthic recovery from the end-Permian mass extinction, recorded

in the microfossil record of level-bottom communities in south China, began in the Smithian Substage, only 1 m.y. after the crisis, and not, as previously claimed, 4–5 m.y. later in the Middle Triassic. In contrast to boreal latitudes, where the initial recovery is seen in nearshore sections, this diversifi cation, primarily of foraminifer assemblages, began in off-shore settings and moved to near-shore and platform carbonate loca-tions. The benthic record contrasts with that of the pelagic biota (ammo-noids and conodonts) that underwent rapid radiation in the immediate aftermath of the end-Permian crisis. The benthic biota does not record evidence for three extinction events seen in the Early Triassic history of pelagic groups (Stanley, 2009). Therefore, these Early Triassic crises do not merit a mass-extinction epithet.

ACKNOWLEDGMENTSThis study was supported by the National Natural Science Foundation of

China (grants 40830212, 40730209, 40921062), the 973 Program (National Basic Research Program; 2011CB808800), the 111 Project (B08030), and the Austra-lian Research Council Discovery Project (grant DP0770938). We thank Doug Erwin, Tom Algeo, and two anonymous reviewers for their comments, and Da-vid Haig for his advice and discussions on the Triassic foraminiferal taxonomy and evolution. This study is a contribution to the International Geoscience Pro-gramme 572, Permian-Triassic Ecosystems.

REFERENCES CITEDBaud, A., Richoz, S., and Pruss, S., 2007, The Lower Triassic anachronistic carbon-

ate facies in space and time: Global and Planetary Change, v. 55, p. 81–89, doi:10.1016/j.gloplacha.2006.06.008.

Brayard, A., Escarguel, G., Bucher, H., Monnet, C., Bruhwiler, T., Goudemand, N., Galfetti, T., and Guex, J., 2009, Good genes and good luck: Ammonoid diversity and the end-Permian mass extinction: Science, v. 325, p. 1118–1121, doi:10.1126/science.1174638.

Erwin, D.H., 1998, The end and the beginning: Recoveries from mass extinction: Trends in Ecology & Evolution, v. 13, p. 344–349, doi:10.1016/S0169-5347(98)01436-0.

Erwin, D.H., 2001, Lessons from the past: Biotic recoveries from mass extinctions: United States of America Academy of Sciences Proceedings, v. 98, p. 5399–5403, doi:10.1073/pnas.091092698.

Flügel, E., 2002, Triassic reef patterns, in Kiessling, W., et al., eds., Phanerozoic reef patterns: SEPM (Society for Sedimentary Geology) Special Publica-tion 72, p. 391–463.

Galfetti, T., Bucher, H., Ovtcharova, M., Schaltegger, U., Brayard, A., Bruhwiler, T., Goudemand, N., Weissert, H., Hochuli, P.A., Cordey, F., and Guodun, K., 2007, Timing of the Early Triassic carbon cycle perturbations inferred from new U-Pb ages and ammonoid biochronozones: Earth and Planetary Science Letters, v. 258, p. 593–604, doi:10.1016/j.epsl.2007.04.023.

Galfetti, T., Bucher, H., Martini, R., Hochuli, P.A., Weissert, H., Crasquin-Soleau, S., Brayard, A., Goudemand, N., Bruhwiler, T., and Guodun, K., 2008, Evo-lution of Early Triassic outer platform paleoenvironments in the Nanpan-jiang Basin (south China) and their signifi cance for the biotic recovery: Sedimentary Geology, v. 204, p. 36–60, doi:10.1016/j.sedgeo.2007.12.008.

on November 2, 2014geology.gsapubs.orgDownloaded from

742 GEOLOGY, August 2011

Hallam, A., 1991, Why was there a delayed radiation after the end-Palaeozoic extinctions?: Historical Biology, v. 5, p. 257–262, doi:10.1080/10292389109380405.

Hallam, A., and Wignall, P.B., 1997, Mass extinctions and their aftermath: Ox-ford, Oxford University Press, 320 p.

Hautmann, M., Bucher, H., Brühwiler, T., Goudemand, N., Kaim, A., and Nützel, A., 2011, An unusually diverse mollusc fauna from the earliest Triassic of south China and its implications for benthic recovery after the end-Permian biotic crisis: Geobios, v. 44, p. 71–85, doi:10.1016/j.geobios.2010.07.004.

Jablonski, D., Sepkoski, J.J., Jr., Bottjer, D.J., and Sheehan, P.M., 1983, Onshore-offshore patterns in the evolution of Phanerozoic shelf communities: Sci-ence, v. 222, p. 1123–1125, doi:10.1126/science.222.4628.1123.

Lehrmann, D.J., Payne, J.L., Felix, S.V., Dillet, P.M., Wang, H.-M., Yu, Y.-Y., and Wei, J.-Y., 2003, Permian-Triassic boundary sections from shallow-marine carbonate platforms of the Nanpanjiang Basin, south China: Implications for oceanic conditions associated with the end-Permian extinction and its aftermath: Palaios, v. 18, p. 138–152, doi:10.1669/0883-1351(2003)18<138:PBSFSC>2.0.CO;2.

Lehrmann, D.J., Ramezani, J., Bowring, S.A., Martin, M.W., Montgomery, P., Enos, P., Payne, J.L., Orchard, M.J., Wang, H., and Wei, J., 2006, Tim-ing of recovery from the end-Permian extinction: Geochronologic and bio-stratigraphic constraints from south China: Geology, v. 34, p. 1053–1056, doi:10.1130/G22827A.1.

Mundil, R., Ludwig, K.R., Metcalfe, L., and Renne, P.R., 2004, Age and timing of the Permian mass extinctions: U/Pb dating of closed-system zircons: Sci-ence, v. 305, p. 1760–1763, doi:10.1126/science.1101012.

Orchard, M.J., 2007, Conodont diversity and evolution through the latest Permian and Early Triassic upheavals: Palaeogeography, Palaeoclimatology, Palaeo-ecology, v. 252, p. 93–117, doi:10.1016/j.palaeo.2006.11.037.

Ovtcharova, M., Bucher, H., Schaltegger, U., Galfetti, T., Brayard, A., and Guex, J., 2006, New Early to Middle Triassic U-Pb ages from South China: Cali-bration with ammonoid biochronozones and implications for the timing of the Triassic biotic recovery: Earth and Planetary Science Letters, v. 243, p. 463–475, doi:10.1016/j.epsl.2006.01.042.

Payne, J.L., Lehrmann, D.J., Wei, J., Orchard, M.J., Schrag, D.P., and Knoll, A.H., 2004, Large perturbations of the carbon cycle during recovery from the end-Permian extinction: Science, v. 305, p. 506–509, doi:10.1126/science.1097023.

Payne, J.L., Lehrmann, D.J., Wei, J., and Knoll, A.H., 2006a, The pattern and tim-ing of biotic recovery from the end-Permian extinction on the Great Bank of Guizhou, Guizhou Province, China: Palaios, v. 21, p. 63–85, doi:10.2110/palo.2005.p05-12p.

Payne, J.L., Lehrmann, D.J., Christensen, S., Wei, J., and Knoll, A.H., 2006b, En-vironmental and biological controls on the initiation and growth of a Mid-dle Triassic (Anisian) reef complex on the Great Bank of Guizhou, China: Palaios, v. 21, p. 325–343, doi:10.2110/palo.2005.P05-58e.

Schubert, J.K., and Bottjer, D.J., 1995, Aftermath of the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western

USA: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 116, p. 1–39, doi:10.1016/0031-0182(94)00093-N.

Solé, R.V., Montoya, J.M., and Erwin, D.H., 2002, Recovery after mass extinc-tion: Evolutionary assembly in large-scale biosphere dynamics: Royal Society of London Philosophical Transactions, ser. B, v. 357, p. 697–707, doi:10.1098/rstb.2001.0987.

Song, H., Tong, J., Chen, Z.Q., Yang, H., and Wang, Y., 2009, End-Permian mass extinction of foraminifers in the Nanpanjiang Basin, South China: Journal of Paleontology, v. 83, p. 718–738, doi:10.1666/08-175.1.

Stanley, G.D.J., 1988, The history of early Mesozoic reef communities: A three-step process: Palaios, v. 3, p. 170–183, doi:10.2307/3514528.

Stanley, S.M., 2008, Predation defeats competition on the seafl oor: Paleobiology, v. 34, p. 1–21, doi:10.1666/07026.1.

Stanley, S.M., 2009, Evidence from ammonoids and conodonts for multiple Early Triassic mass extinctions: United States of America National Academy of Sci-ences Proceedings, v. 106, p. 15264–15267, doi:10.1073/pnas.0907992106.

Wignall, P.B., 2008, The end-Permian crisis, aftermath and subsequent recovery, in Okada, H., et al., eds., Origin and evolution of natural diversity, 21st Century Center of Excellence (COE) for Neo-Science of Natural History: Hokkaido, Japan, Hokkaido University, p. 43–48.

Wignall, P.B., and Twitchett, R.J., 2002, Permian-Triassic sedimentology of Jameson Land, East Greenland: Incised submarine channels in an anoxic ba-sin: Geological Society of London Journal, v. 159, p. 691–703, doi:10.1144/0016-764900-120.

Wignall, P.B., Morante, R., and Newton, R., 1998, The Permo-Triassic transition in Spitsbergen: δ13Corg chemostratigraphy, Fe and S geochemistry, facies, fauna and trace fossils: Geological Magazine, v. 135, p. 47–62, doi:10.1017/S0016756897008121.

Wignall, P.B., Bond, D.P.G., Kuwahara, K., Kakuwa, K., Newton, R.J., and Poul-ton, S.W., 2010, An 80 million year oceanic redox history from Permian to Jurassic pelagic sediments of the Mino-Tamba terrane, SW Japan, and the origin of four mass extinctions: Global and Planetary Change, v. 71, p. 109–123, doi:10.1016/j.gloplacha.2010.01.022.

Yin, H., 1985, Bivalves near the Permian-Triassic boundary in South China: Jour-nal of Paleontology, v. 59, p. 572–600.

Zonneveld, J.-P., Gingras, M.K., and Beatty, T.W., 2010, Diverse ichnofossil as-semblages following the P-T mass extinction, Lower Triassic, Alberta and British Columbia, Canada: Evidence for shallow marine refugia on the northwestern coast of Pangaea: Palaios, v. 25, p. 368–392, doi:10.2110/palo.2009.p09-135r.

Manuscript received 18 February 2011Manuscript accepted 14 March 2011

Printed in USA

ERRATUM

Pre-eruptive reheating during magma mixing at Quizapu volcano and the implications for the explosiveness of silicic arc volcanoes

Philipp Ruprecht and Olivier Bachmann(Geology, vol. 38, no. 10, p. 919–922)

In Figure 2B, the viscosities were calculated using degrees C instead of K. The correct Figure 2 is provided here.

Consequently, the fi rst two sentences of the fi rst paragraph of the section titled EFFECT OF MAGMA MIXING AND REHEATING ON ERUP-TION DYNAMICS should read as:

“Mixing and reheating that occurred prior to the 1846–1847 eruption had a major effect on magma viscosity. Applying viscosity models for silicic melts (Hess and Dingwell, 1996) and multiphase mixtures (Beckermann and Viskanta, 1993), we fi nd that bulk viscosities of the 1846–1847 mag-mas are ~2–3 times lower than the magma erupted in 1932 (Fig. 2B).”

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