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Progressive development of ocean anoxia in the end-Permian pelagic Panthalassa

Satoshi Takahashi¹, Rie S. Hori², Satoshi Yamakita³, Yoshiaki Aita⁴, Atsushi Takemura⁵, Minoru Ikehara⁶, Yijun Xiong⁷, Simon W. Poulton⁸, Paul B. Wignall⁸, Takaaki Itai¹, Hamish J. Campbell⁸, Bernard K. Spörli⁹

1. University of Tokyo, 2. Ehime University,

3. Miyazaki University, 4.Utsunomiya University,

5. Hyogo University of Teacher Education,

6. Kochi University, 7. University of Leeds,

8. GNS Science, 9. University of Auckland

End-Permian Mass Extinction

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背景：ペルム紀ー三畳紀境界の大量絶滅事変と海洋環境

?

pelagic

Distribution：

１．China　2．Iran　３.Italia

4. India　５．Canada，６．Canada

７．Japan　８．New Zealand

~2500 km

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研究目的:大量絶滅期前後の貧酸素海洋環境の時空間分布の解明

Geographic position of the study section (Waiheke section, New Zealand)

Figure 1. Location map of the studied Permian-Triassic section (Waiheke 1 section, New Zealand). (B) Paleo-geographical map of the Permian-Triassic showing the depositional position of pelagic deep-sea Permian-Triassic boundary sections. Labeled numbers of 1-7 indicate following localities. (1) pelagic sections belong to New Zealand accretionary complexes such as Waiheke section (Spörli et al., 2007). (2) pelagic sections belong to Japanese accretionary complexes. (3) shallow marine sections belong to Nanpanjiang Basin such as Meishan and Ganxi, South China, (4) sections in Sverdrup Basin, arctic Canada (Grasby and Beauchamp, 2011), (5) sections in Peace River Basin, western Canada (Heys et al., 2007), (6) sections in Arabian Margin (Clarkson et al., 2017). (7) sections in Sydney Basin (Fielding et al., 2019; Vajada et al., 2020). (B) Locality of the Waiheke-1 section (WHK1) in the North Island of New Zealand. Distribution of the Triassic-Jurassic accretionary complex is based on Black (1994) and Begg and Johnson (2000). Locality of Arrow Rocks is also shown.

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研究対象：Waiheke 1 section (WHK 1)

Hori et al., 2011

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化学指標: redox-sensitive elements in sedimentary rocks

Sulfidic water evidence

Poulton (2021)

Sulfidic water

evidence

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　Methods：Major & trace elements analysis （ICPAES, ICPMS）

Powdering the samples

（agate mortal）

Acid treatments（HNO₃HCｌO₄,HF）

ICP-AES (Hitachi)(@Y. Takahashi Lab)

ICP-MS,

（Thermo　icap : University of Tokyo）

微量元素成分

(Li．．．．．．U)

※誤差＞±1％

TRUST me

I did by myself

手法1：酸化還元鋭敏元素の分析（東京大学）

RSD＜5−10％

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手法２：鉄化学種の分画（リーズ大学）

(Poulton & Canfield 2005; Thompson et al., 2019; Alcott et al., 2020^NEW)

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結果・考察１: Carbon isotope profile and redox indicators of the Waihkeke-1 section

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結果･考察２: Carbon isotope correlation

Figure 4. Stratigraphic correlation of the Permian-Triassic boundary sections of the Meishan section, Waiheke 1 section, Arrow Rocks section, Akkamori 2 section, and Ubara section. Compiled data of the Meishan section are based on Jin et al. (2000), Cao et al. (2002), Kaiho et al. (2009), and Burgess et al. (2014). Data of Arrow Rocks, Akkamori and Ubara sections are modified from Hori et al. (2007), Takahashi et al. (2010) and Kaiho et al. (2016), respectively. The horizontal bars indicate correlative stratigraphic zones around Permian-Triassic boundary. Green: the first decrease in carbon isotope ratio (δ¹³C) in the latest Changhsingian, Blue: the second decrease in δ¹³C in latest Changhsingian coinciding with the end-Permian mass extinction event (EPME), Pink: the interval from δ¹³C minimum at EPME (end-Permian mass extinction event) to δ¹³C increase toward PTB (Permian-Triassic boundary).

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結果･考察３:遠洋域環境記録の比較（ Mo/Al, U/Al）

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結果・考察４：海洋モリブデン濃度の減少記録

Figure 6. Cross plots of molybdenum (Mo) and uranium (U) enrichment factors (Mo_EF and U_EF, respectively) from Panthalassic PTB sections of Waiheke 1, Arrow Rocks, Akkamori, and Ubara. The data of Arrow Rocks, Akkamori 2, and Ubra are modified from Hori et al. (2007), Takahashi et al. (2014), and Algeo et al. (2011), respectively. The lines connecting respective plots mean the track corresponding to secular variations demonstrated in Figures 4 and 5. Black: Changhsingian before the δ¹³C decreases, Green: the first decrease in carbon isotope ratio (δ¹³C) in the latest Changhsingian, Blue: the second decrease in δ¹³C in latest Changhsingian coinciding with the end-Permian mass extinction event (EPME), Pink: the interval from δ¹³C minimum at EPME (end-Permian mass extinction event) to δ¹³C increase toward PTB (Permian-Triassic boundary), Grey: Earliest Triassic (Griesbachian) after PTB. Superimposed grey-coloured areas of modern oceanic sediments are referred from Algeo et al., (2009) and Tribovillard et al. (2012). The U/Mo_SW is weight ratio in modern seawater (SW) which ranges from 3.0 to 3.1 (modern Pacific and Atlantic, respectively; Anderson, 1987; Bruland, 1983; Chen et al., 1986; Emerson and Huested, 1991).

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考察：海洋無酸素化の背景

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Highlights:

1. Redox record across the end-Permian mass extinction event in the south middle latitude pelagic Panthalassa.

2. Euxinic water condition developed at the end−Permian inferred from high Fe_HR/Fe, Fe_pyrite/Fe, Fe/Al, Mo/Al, U/Al.

3. Gradual developments of oceanic anoxia from low latitude

then middle latitude Panthalassa during more than 100 kilo years before the mass extinction event.

4. The compiled four Panthalassa sections commonly suggest seawater Mo drawdown trends in the earliest Triassic Panthalassa.

5. The progressive Panthalassic anoxia toward the end-Permian overlap the timing of Siberian Traps activity and terrestrial vegetation loss, and finally coincides with extreme climate warming.

Latest Data File: ver. 2021/3/03

要点:

1. ペルム紀-三畳紀境界期の中緯度南半球遠洋域の酸化還元環境の記録の報告 (WHK-1セクション　New Zealand).

2. 大量絶滅期に硫化水素環境が発達した証拠がFe_pyrite/Fe_HR、Fe/Al, Mo/Al、U/Alの高い値から示された．

3. 炭素同位体比の変動により複数のPT境界を対比すると、南半球遠洋における無酸素環境の発達は、低緯度遠洋域の記録にみられるものよりも最大で10万年ほど遅れる。

4. 硫化水素水塊の発達後から最前期三畳紀の層準から、現在報告のあるほぼ全ての遠洋深海成ペルム紀-三畳紀境界セクションで海水Mo濃度の減少が起きていたことが示される。

5. 低緯度-南半球中緯度へと進行した遠洋域の無酸素水塊の発達は、当時の陸域の火成活動と植生減少、気候温暖化と同時性がある。

まとめ：中緯度と低緯度の酸化還元環境の相違点

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Waiheke 島調査

Thank you!

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海洋無酸素の記録を得る手段１:元素組成

Compiled by Scholz, 2018

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Criteria for redox condition

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海洋無酸素の記録を得る手段２:数値モデリング

Winguth and Winguth (2011)

Penn et al (2018)

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背景:大量絶滅とその回復期の生態系(後期ペルム紀−三畳紀)

Corals

Sponge, brachiopods, foraminifers, radiolarians

Song et al., 2018

@Utrecht

End-Permian Mass Extinction

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For understanding global environment: How was pelagic ocean?

IGCP 572, 630

?

pelagic

Algeo et al. (2011)

Distribution：

１．China　2．Iran　３.Italia

4. India　５．Canada，６．Canada

７．Japan　８．New Zealand

~2500 km

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おわり

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Discussion：Amount of Molybdenum deposition

Global seafloor area　=　36×10^７km^２

Sea-water Mo concentration＝105 nＭ (Collier R. W, 1985)

Residence time＝ca.800 kilo yr. >> sedimentation rate

4.9•10⁸ g/km² ≒ 9000 ppm•10^–6•2.74 g/cm³•2.0 cm•10¹⁰ km²/cm²

Total Mo into the deep-sea sediment in the basal 0–2 cm of the end-Permian black claystone: 4.9×１0^８g/km²

1.456 ×10¹⁶ｇ=96[g/mol]×105×10^-9［mol/L］×36×10⁷［km²］　　　　　　　　　

　　　　　　　　　　　×4[km]×10¹²[1000cm³/km³]

Instantaneous inventory of Mo within the residence time：1.46×10¹⁶ｇ

4.9×１０^８g/km²

1.46×10¹⁶ｇ

Area of euxinic seafloor required for drawdown

≒　2.0×１０^７ｋｍ^２（6% of seafloor）

Winguth and Winguth （2009)

For further discussion

The calculations test the minimum extent of euxinic seafloor required for a global seawater drawdown of Mo.

We adopt the sedimentation rates of the 20 kyr/couplet for siliceous claystone

Using these modern oceanic values and assumption, simple division process was conducted.

Seafloor area is ten to the seven power square kilometere.

Result of that total Mo devided by Instantaneous inventory is accords to 2.0 10 to the 7 power square kilometere quarl 6% of global sea floor. 100 times larger than modern ocean condition.

These calculations suggest that when more than 6% of the global pelagic sea became euxinic, as was much of the study section, most of the dissolved Mo would precipitate into sediments, resulting in a global element- depleted seawater condition.

This area estimation is plausible, because the geophysical simulation of the end-Permian anoxic ocean (Winguth and Winguth, 2011, 2013) indicates that the eastern half of the low-latitude oceanic area (accounting for ca. 10–15% the oceanic area) has significantly high productivity, given oxygen consumption beneath the deep seafloor with a ten-fold phosphate (P) supply.

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研究背景：史上最大の大量絶滅事件(2.5億年前)

Community Earth System Model (CESM1), Black et al., 2018

700 ppm

pCO₂

2000 TG SO₂/yr

5600 ppm

2800 ppm

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化学指標: redox-sensitive elements in sediments

Sulfidic water evidence

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手法２：酸化還元鋭敏元素の分析（東京大学）

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古生物学の事典、出版準備中

海水中の酸化還元鋭敏元素の変化（Moの増加と減少）

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Figure 3: Thin sections