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burial velocity =1.5768 km/m.y

ドキュメント内 ࿴Ἠᒣ⬦ᆅᇦ࡟࠾ࡅࡿ㡿ᐙ̿࿴Ἠᖏࡢ (ページ 100-115)

(0–50 m.y.)

( 1000, 1000) ( 500, 500)

numerical solutions

sections ( time, depth)

1000km 50km Zmax= Zmax= 8.0

6.0 0.30 0.35

A

B

Fig. 30. Comparison between analytical solutions and numerical solutions of

these models. A: thermal discrepancy caused by discontinuous a boundary of

physical properties in the sediment– basement column. B: Computational errors

of the heat flow for discretization of time and depth.

0 20

20 0

0

10

Ћdepth (km)

0

10

Ћdepth (km)heat flowЍ

time (m.y.)Ѝ Ќ100 mW/m2

Ќ100 mW/m2

100 mW/m2

sections 4000(for depth)×2000(for time)

subsidence

(0.946 km/m.y

.)Ѝ

depth=5 km surface depth=10 km no subsidenceЍ

non subsidenceЍ sedimentation (0.788 km/m.y

.)Ѝ

uplift (0.946 km/m.y .)Ѝ

heat flowЍ

time (m.y.)Ѝ 100 mW/m2

thermal conductivity = 3.0(W m-1K-1)

heat capacity =3.0™106(J m-3K-1)

thermal conductivity = 4.0(W m-1K-1)

heat capacity =2.4™106(J m-3K-1)

thermal conductivity = 3.0(W m-1K-1)

heat capacity =3.0™106(J m-3K-1)

thermal conductivity = 4.0(W m-1K-1)

heat capacity =2.4™106(J m-3K-1)

sections 4000(for depth)×2000(for time)

burial (0.946 km/m.y

.)Ѝ

depth=5 km surface depth=10 km no subsidence→

Ў300K Ў300K

8 8

10 16

isotherm (50Υ contour interval)

isotherm (50Υ contour interval)

A

B

Fig. 31.Numerical models of thermal condition for subsidence, sedimentation and uplift. Time series variation of temperature distribution in the sediment–

basement column and heat flows among surface, 5 km, and 10 km depths. A:

subsidence and steady state. B: subsidence, steady state, and uplift in a

restricted sedimentation rate. Gradation of colors from blue to orange-red

represents difference of temperature ranging from 300 K to 600 K.

ࢩ࣑࣮ࣗࣞࢩࣙࣥ࡟ࡣJIS Full BASICࡢ୍ࡘ࡛࠶ࡿUltraBasic v.3ࢆ౑⏝ࡋࡓ㸬ࣉࣟࢢ

࣒ࣛࡢᇶᮏᵓ㐀ࡣ௨ୗࡢࣜࢫࢺࡢ㏻ࡾ࡛࠶ࡿ㸦ࣜࢫࢺ㸰㸧㸬ࡲࡓ㸪」ᩘ᮲௳ࡢࣃࢫࢆྠ᫬ィ

⟬ࡋ㸪ࡑࡢ᫬㛫ⓗኚ໬⾲♧࡟ᑐᛂࡍࡿࣂ࣮ࢪࣙࣥࡶసᡂࡋࡓ㸬

ࣜࢫࢺ㸰

㸳㸬㸰㸬㸰 ሁ✚┅࡛ࡢᇙἐຠᯝࡢ᳨ウ

᭱ึ࡟⡆༢࡞᮲௳࡛ࡢࢩ࣑࣮ࣗࣞࢩࣙࣥࢆ࠸ࡃࡘ࠿ᐇ⾜ࡋࡓ㸬Ꮝ㝽ࡢᏑᅾࡋ࡞࠸ᆒ㉁࡞

ሁ✚≀ࡢᇙἐ࡟࠾࠸࡚㸪ሁ✚≀ࡢሁ✚㏿ᗘࢆไ㝈ࡋࡓሙྜ࡜ୖ᪼㐣⛬࡛ࡢ ᗘᵓ㐀࣭⇕ὶ 㔞ࡢኚ໬ࢆㄪ࡭ࡓ㸦Fig. 31㸧㸬୺࡞≀ᛶ᮲௳࣭ቃ⏺᮲௳ࡣ㸪ᇶ┙ᒾࡢ⇕ఏᑟᗘ3.0 W/mK㸪

⇕ᐜ㔞3.0™106 J/m3㸪⇕⏕⏘0 μW/m3㸪ሁ✚≀ࡢ⇕ఏᑟᗘ4.0 W/mK㸪⇕ᐜ㔞2.4™106 J/m3

⇕⏕⏘0 μW/m3㸪ୗ㝈῝ᗘࡣ㸪10 km࡛ୖ㝈ࡀ300 Kࡢࢹ࢕ࣜࢡࣞ᮲௳㸪ୗ㝈ࡀ100 mW/m2 ࡢࣀ࢖࣐ࣥ᮲௳࡜ࡋࡓ㸬ᇙἐ᮲௳ࡣ㸪A㸸ᮇ㛫0㹼8 m.y.᫬࡟ỿ㝆㏿ᗘ0.946 km/m.y.㸦3 μm/s㸧㸪

ࡑࡢᚋ㸦8㹼20 m.y.᫬㸧ࡣỿ㝆࣭ୖ᪼࡜ࡶ⏕ࡌ࡞࠸㸬ሁ✚㏿ᗘࡣỿ㝆㏿ᗘ࡜ྠࡌ㸦඲ᇙ✚㸧

࡜ࡋࡓ㸬B㸸ᮇ㛫0㹼8 m.y.᫬࡟ỿ㝆㏿ᗘ0.946 km/m.y.㸦3 μm/s㸧㸪ᮇ㛫8㹼16 m.y.᫬ࡣỿ 㝆࣭ୖ᪼࡜ࡶ⏕ࡌࡎ㸪ᮇ㛫16㹼20 m.y.᫬࡟ୖ᪼㏿ᗘ0.946 km/m.y.㸦3 μm/s㸧࡛࠶ࡿ㸬ሁ

✚㏿ᗘࡣ0.788 km/m.y.㸦2.5 μm/s㸧࡜ࡋࡓ㸬ࡑࡢ⤖ᯝ㸪඲ᇙ✚ࡢሙྜ㸪ỿ㝆ࡀ೵Ṇᚋ࡟㏿

ࡸ࠿࡟⇕ὶ㔞ࡢୖ᪼ࡀ⏕ࡌࡿ㸬ࡑࢀ࡜ྠ᫬࡟ᆅ ໙㓄ࡀୖ᪼ࡋྛ➼ ⥺ࡢ῝ᗘࡀὸࡃ࡞ࡿ㸬

௚᪉㸪ሁ✚㏿ᗘࡀỿ㝆㏿ᗘࡼࡾ㐜࠸ሙྜ㸪ᇶ┙ࡢỿ㝆ࡀ೵Ṇᚋࡢᇙ✚ࡀ᏶஢ࡍࡿࡲ࡛ࡢᮇ 㛫ࡢᆅẆ⇕ὶ㔞ࡣ㸪ึᮇ್ࡲ࡛ᅇ᚟ࡏࡎ࡟ῶᑡഴྥࢆ⥔ᣢࡍࡿࡇ࡜ࡀุ᫂ࡋࡓ㸬ࡇࢀࡣ᪂ ࡓ࡞ሁ✚≀ࡀ౪⤥ࡉࢀ⥆ࡅࡿሁ✚≀⾲㠃௜㏆ࡔࡅ࡛࡞ࡃ㸪῝ᗘ5 km࡟࠾࠸࡚ࡶྠᵝ࡛࠶ࡗ

ࡓ㸬㸦Fig. 31A㸧㸬ᇙ✚࡟ࡼࡾሁ✚≀ୖ㠃ࡢ῝ᗘࡀୖ᪼ࡍࡿࡓࡵ㸪⤖ᯝⓗ࡟➼ ⥺ࡢ῝ᗘࡣୖ

᪼ࡍࡿࡀ㸪ᆅ ໙㓄ࡣୖ᪼ࡋ࡚࠸࡞࠸㸬୧ࣔࢹࣝ࡟ࡘ࠸࡚㸪ᇶ┙ᒾ┤ୖࡢ ᗘኚ໬࡟ὀ┠

ࡍࡿ࡜㸪ሁ✚㏿ᗘࢆไ㝈ࡋࡓሙྜࡢ࡯࠺ࡀప࠸ ᗘᒚṔࢆ㎺ࡗ࡚࠸ࡿ㸬ࡲࡓ㸪ୖ᪼࡟㌿ࡌ

ࡿ࡜㸪ୖ㝈ቃ⏺࡛ࡣୗ㝈ቃ⏺ࡼࡾ㧗࠸⇕ὶ㔞࡜࡞ࡿ㸬

ḟ࡟㸪ᇶ┙ᒾࡀỿ㝆ᚋࡍࡄ࡟ୖ᪼࡟㌿ࡌࡿሙྜࡢࢩ࣑࣮ࣗࣞࢩࣙࣥ࡜ࡋ࡚㸳᮲௳ࢆẚ㍑

ࡋࡓ㸦Fig. 32A–E㸧㸬୺࡞≀ᛶ᮲௳࣭ቃ⏺᮲௳ࡣ๓㏙ࡢࣔࢹࣝ㸦Fig. 31㸧࡜ྠᵝ࡛࠶ࡿ㸬ᇙ ἐ᮲௳ࡣ㸪A㸸ᮇ㛫0㹼5 m.y.᫬࡟ỿ㝆㏿ᗘ1.892 km/m.y.㸦6 μm/s㸧࡛㸪ᮇ㛫5.1㹼10 m.y

᫬࡟ୖ᪼㏿ᗘ0.315 km/m.y.㸦1 μm/s㸧࡛࠶ࡿ㸬B㸸ᮇ㛫0㹼5 m.y.᫬࡟ỿ㝆㏿ᗘ1.892 km/m.y.

㸦6 μm/s㸧࡛㸪ᮇ㛫5.1㹼10 m.y᫬࡟ୖ᪼㏿ᗘ1.103 km/m.y.㸦3.5 μm/s㸧࡛࠶ࡿ㸬C㸸ᮇ 㛫0㹼5 m.y.᫬࡟ỿ㝆㏿ᗘ1.892 km/m.y.㸦6 μm/s㸧࡛㸪ᮇ㛫5.1㹼10 m.y᫬࡟ୖ᪼㏿ᗘ1.892 km/m.y.㸦6 μm/s㸧࡛࠶ࡿ㸬A–B࡛ࡣሁ✚㏿ᗘࡣỿ㝆㏿ᗘ࡜ྠࡌ࡜ࡋࡓ㸬D㸸ᮇ㛫0㹼5 m.y.

᫬࡟ỿ㝆㏿ᗘ1.892 km/m.y.㸦6 μm/s㸧࡛㸪ᮇ㛫5.1㹼10 m.y.᫬࡟ୖ᪼㏿ᗘ1.892 km/m.y.

㸦6 μm/s㸧࡛࠶ࡿ㸬ሁ✚㏿ᗘࢆ0.946 km/m.y.㸦3 μm/s㸧࡟ไ㝈ࡋࡓ㸬E㸸ỿ㝆࣭ୖ࣭᪼ሁ

✚㏿ᗘࡣࣔࢹࣝ D࡜ྠ᮲௳࡛࠶ࡿࡀ㸪⌧ᅾࡢᾏὒࡢప⦋ᗘᆅᇦࡢ ᗘᵓ㐀ࢆཧ⪃࡟ࡋ࡚ሁ

✚≀ୖ㠃ࡢ ᗘࢆỈ῝࡜ඹ࡟ኚ໬ࡉࡏࡓ㸬Ỉ῝࡟ࡼࡿ ᗘ᮲௳ࡣ273+27™exp(㸫z㸭2618) 㸦zࡣ῝ᗘ㸦㹫㸧㸪 ᗘࡢ༢఩ࡣK㸧࡛࠶ࡾ㸪Ỉ῝0 m࡛ࡣ300 K㸪Ỉ῝5000 m࡛ࡣ⣙277 K㸦4Υ㸧࡜ࡋࡓ㸬 ᗘศᕸ୰ࡢ㟷⥺ࡣࡑࢀࡒࢀᇶ┙ᒾࡼࡾ3 kmୖ఩ࡢሁ✚≀ࡢᇙἐࣃࢫ

࡛࠶ࡿ㸬ࡇࢀࡽࡢ ᗘࣃࢫ࠾ࡼࡧ⿕⇕࡟ࡼࡿࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡ࢆFig. 33࡟♧ࡋࡓ㸬 ࡑࡢ⤖ᯝ㸪࠸ࡃࡘ࠿ࡢὀ┠ࡍ࡭ࡁ⌧㇟ࡀㄞࡳྲྀࢀࡓ㸬ỿ㝆ᚋࡢ㏿ࡸ࠿࡞ୖ᪼࡟ᛂࡌ࡚⇕

ὶ㔞࠾ࡼࡧᆅ ໙㓄ࡣୖ᪼࡟㌿ࡌࡿࡀ㸪ୖ᪼㏿ᗘࡀ኱ࡁ࠸࡯࡝⇕ὶ㔞ࡢୖ᪼㏿ᗘ࡜ୖ᪼㔞

3 km3 km3 km

0 10

10 0

0

10

Ћdepth (km)

0

10

Ћdepth (km)heat flowЍ

time (m.y.)Ѝ Ќ100 mW/m2

Ќ100 mW/m2

100 mW/m2

sections 4000(for depth)×2000(for time)

subsidence (1.892 km/m.y

.)Ѝ

depth=5 km surface depth=10 km uplift (1.892 km/m.y

.)Ѝ uplift (0.315 km/m.y

.)Ѝ

heat flowЍ

time (m.y.)Ѝ 100 mW/m2

thermal conductivity = 3.0(W m-1K-1)

heat capacity =3.0™106(J m-3K-1)

thermal conductivity = 4.0(W m-1K-1)

heat capacity =2.4™106(J m-3K-1)

sections 4000(for depth)×2000(for time)

burial (1.892 km/m.y

.)Ѝ

depth=5 km surface depth=10 km

Ў300 K Ў300 K

uplift (1.103 km/m.y .)Ѝ

A

C

0 10 0

10

Ћdepth (km)heat flowЍ

time (m.y.)Ѝ Ќ100 mW/m2

100 mW/m2

sections 4000(for depth)×2000(for time)

subsidence (1.892 km/m.y

.)Ѝ

depth=5 km surface depth=10 km

Ў300K

5 5.1 5 5.1

5 5.1

B

isotherm (50Υ contour interval)

isotherm (50Υ contour interval)

isotherm (50Υ contour interval)

3 km3 km

0 10 0

10

Ћdepth (km)heat flowЍ

time (m.y.)Ѝ Ќ100 mW/m2

100 mW/m2

sections 4000(for depth)×2000(for time)

subsidence

(1.892 km/m.y

.)Ѝ

depth=5 km surface depth=10 km uplift (1.892 km/m.y

.)Ѝ

Ў273+27exp(depth

2618) K

uplift (1.892 km/m.y .)Ѝ

Fig. 32. Comparison of thermal models for five conditions. A–C: Rapid subsidence followed by slow to rapid uplift. D: Rapid subsidence followed by rapid uplift in a restricted sedimentation rate. E: Rapid subsidence followed by rapid uplift in a restricted sedimentation rate and variable surface temperature for depth. Gradation of colors from blue to orange-red represents difference of temperature ranging from 300 K to 700 K.

E

0 10 0

10

Ћdepth (km)heat flowЍ

time (m.y.)Ѝ Ќ100 mW/m2

100 mW/m2

sections 4000(for depth)×2000(for time)

subsidence (1.892 km/m.y

.)Ѝ

depth=5 km surface depth=10 km sedimentation (0.946 km/m.y

.)Ѝ

sedimentation (0.946 km/m.y

.)Ѝ

isotherm (50Υ contour interval)

isotherm (50Υ contour interval)

Ў300 K

5 5.1 6.8

6.8 5 5.1

D

ࡀ኱ࡁ࠸ࡇ࡜ࡀࢃ࠿ࡿ㸦Fig. 32A–C㸧㸬ࡋ࠿ࡋ㸪ࣔࢹࣝA࠿ࡽCࡢሁ✚≀ࡢᇙἐࣃࢫ࡜ࡑ ࡢ ᗘኚ㑄ࢆẚ㍑ࡋ࡚ࡳࡿ࡜㸪ୖ᪼㏿ᗘࡀᑠࡉ࠸࡯࠺ࡀ㸪⤒㦂ࡍࡿ᭱㧗ྂᆅ ࡣ㧗࠸ࡇ࡜

ࡀㄞࡳྲྀࢀࡿ㸦Fig. 33㸧㸬ࡍ࡞ࢃࡕ㸪ୖ᪼㏿ᗘࡀ኱ࡁ࠸࡯࡝ᆅ ໙㓄ࡢୖ᪼㔞ࡀ኱ࡁ࠸ࡀ㸪

ྠࡌ῝ᗘࡲ࡛฿㐩ࡋࡓሁ✚≀ࡢ ᗘᒚṔࢆẚ㍑ࡍࡿ࡜㸪⤖ᒁୖ᪼㏿ᗘࡀ኱ࡁ࠸࡯࡝᭱㧗ྂ

ᆅ ࡀపࡃ࡞ࡿࡇ࡜ࡀ♧၀ࡉࢀࡿ㸬ࡲࡓ㸪඲ᇙ✚࡜ሁ✚㏿ᗘࢆไ㝈ࡋࡓሙྜࢆẚ㍑ࡍࡿ࡜

㸦Fig. 32C, D㸧㸪ࣔࢹࣝD࡛ࡣࣔࢹࣝC࡜ẚ㍑ࡋ࡚᭱㧗ྂᆅ ࡀ64Υప࠸ ᗘࣃࢫ࡜࡞ࡗ

ࡓ㸦Fig. 33㸧㸬ሁ✚㏿ᗘࡀไ㝈ࡉࢀࡓศࡔࡅሁ✚≀ୖ㠃ࡢᶆ㧗ࡀୗࡀࡿࡓࡵ㸪ࣔࢹࣝ A–C

࡜ࣔࢹࣝD㸪E࡛ࡣᇶ┙ࡢ᭱኱ᇙ✚῝ᗘ࠾ࡼࡧࡑࡢ᫬ᮇࡀ␗࡞ࡿ㸦Fig. 33㸧㸬඲ᇙ✚ࡢࣔࢹ

ࣝA–C࡛ࡣ㸪᭱኱ᇙ✚῝ᗘࡣ9.46 km࡛㸪ࡑࡢᮇ㛫ࡣ5.0–5.1 m.y.᫬࡛࠶ࡿ㸬ሁ✚㏿ᗘไ 㝈ࡢࣔࢹࣝD㸪E࡛ࡣ᭱኱ᇙ✚῝ᗘࡣ⣙6.5 km࡛㸪ᇙ✚ࡀ᏶஢ࡍࡿ⣙6.8 m.y.᫬࡛࠶ࡾ㸪

᭱኱ỿ㝆᫬ࡢ5.0–5.1 m.y.᫬ࡢᇙ✚῝ᗘࡣ4.73 km࡛࠶ࡿ㸬ࡇࡢ୧⪅ࡢ᭱኱ᇙ✚῝ᗘᕪࡣ㸪 ỿ㝆ᚋࡢୖ᪼㏿ᗘࡀᑠࡉࡃሁ✚㏿ᗘࡀ኱ࡁ࠸࡯࡝ᑠࡉࡃ࡞ࡿ㸬௚᪉㸪ሁ✚≀ୖ㠃࡛ࡢ⇕ὶ 㔞ࡢῶᑡ㔞ࡣ㸪ሁ✚㏿ᗘࡀᑠࡉ࠸࡯࡝ᑠࡉࡃ࡞ࡗࡓ㸬᭱㧗ྂᆅ ࢆ⤒㦂ࡍࡿᮇ㛫ࡣ㸪㸱ࡘ ࡢࣔࢹࣝ࡜ࡶୖ᪼ࢆ㛤ጞࡍࡿ5.1 m.y.᫬ࡼࡾᩘm.y.ᚋ࡛࠶ࡗࡓ㸦Fig. 33㸧㸬ࣔࢹࣝD࡟࠾࠸

࡚㸪ୖ᪼࡟㌿ࡌࡓ5.1 m.y.᫬௨㝆ࡢ⾲㠃࡛ࡢ⇕ὶ㔞ࡣ㸪ỿ㝆᫬࡜ྠᵝ࡟ୗ㝈࠿ࡽ౪⤥ࡉࢀࡿ

⇕ὶ㔞ࡼࡾᑠࡉ࠸㸬ࡋ࠿ࡶࡑࡢᙳ㡪ࡣሁ✚≀⾲㠃௜㏆ࡔࡅ࡛࡞ࡃ㸪῝ᗘ5 kmࡢ⇕ὶ㔞࠿ࡽ

ࡶㄞࡳྲྀࢀࡿ㸬ࣔࢹࣝA–C࡜ࣔࢹࣝD࡛᭱㧗ྂᆅ ࡟኱ࡁ࡞ᕪࡀ⏕ࡌࡓ᭱኱ࡢཎᅉࡣ㸪᭱

኱ỿ㝆᫬ࡢᇙ✚῝ᗘࡢ㐪࠸࡛࠶ࢁ࠺ࡀ㸪ࡶ࠺୍ࡘࡢ㔜せ࡞せᅉ࡜ࡋ࡚㸪ୖ᪼᫬࡟౪⤥ࡀ⥆

࠸ࡓሁ✚≀ࢆ ࡵࡿࡓࡵ࡟ᚲせ࡞⇕㔞ࡀᣲࡆࡽࢀࡿ㸬ࡍ࡞ࢃࡕ㸪᪂ࡓ࡞ሁ✚≀ࡢ౪⤥ࡣ㸪 ሁ✚┅ࡢୖ᪼᫬࡟࠾࠸࡚ࡶ⇕ὶ㔞ࡢῶᑡࡢ኱ࡁ࡞せᅉ࡜࡞ࡗࡓࡇ࡜ࡀ♧၀ࡉࢀࡿ㸬ࡇࢀࡀ

ୖ᪼᫬ࡢ ᗘୖ᪼ࢆ⦆࿴ࡋࡓࡢࡔࢁ࠺㸬ࡉࡽ࡟㸪ࣔࢹࣝD࡜ࣔࢹࣝE࡟ࡘ࠸࡚ྠࡌ῝ᗘࡲ

࡛฿㐩ࡋࡓሁ✚≀ࡢ ᗘᒚṔࢆẚ㍑ࡍࡿ࡜㸪ࣔࢹࣝ E ࡢ࡯࠺ࡀ᭱㧗ྂᆅ ௜㏆࡛ࡢ⿕⇕ 

ᗘࡀ6Υప࠸㸦Fig. 33㸧㸬ᾏὒࡢ୍⯡ⓗ࡞ ᗘᵓ㐀ࢆ⪃៖ࡍࡿ࡜ࣔࢹࣝEࡀ⮬↛᮲௳࡟㏆࠸

࡜⪃࠼ࡽࢀࡿࡔࢁ࠺ࡀ㸪ࡇࡢᙳ㡪ࡣᆅୗ࡟࠾࠸࡚ࡶ༑ᩘᗘࡢ ᗘᕪ࡜࡞ࡾỴࡋ࡚↓ど࡛ࡁ

ࡿ࡯࡝ᑠࡉ࠸ࡶࡢࡣ࡞࠸ࡇ࡜ࡀ♧၀ࡉࢀࡓ㸬ࣔࢹࣝD࠾ࡼࡧEࡢ᮲௳࡟ࡼࡿ ᗘᵓ㐀࡬ࡢ ᙳ㡪ࡣ㸪࡝ࡕࡽࡢࢣ࣮ࢫࡶሁ✚┅⦕㎶㒊ࡼࡾᇙἐ㏿ᗘࡀᛴ㏿࡛Ỉ῝ࡀ῝࠸࡜⪃࠼ࡽࢀࡿሁ

✚┅୰ᚰഃࡢᆅୗ ᗘ≧ែࢆࡼࡾప ໬ࡉࡏࡿ᪉ྥ࡟స⏝ࡍࡿࡇ࡜࡟࡞ࡿ㸬

㸳㸬㸰㸬㸱 ࿴Ἠሁ✚┅ࡢᇙἐࢩ࣑࣮ࣗࣞࢩࣙࣥ

᭷ᶵ≀⇍ᡂࡢࢧࣈ࣮ࣝࢳࣥࢆᶵ⬟ࡉࡏࡓ࿴Ἠሁ✚┅ࡢලయⓗ࡞ᇙἐࣔࢹࣝࢆ᳨ウࡍࡿ㸬

࿴Ἠᒙ⩌ࡢࣔࢹ࡛ࣝࡣ㸪ࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡࡟ࡼࡿ⇍ᡂ≧ែࡢ≉ᚩ࡜ࡋ࡚࡝ࡢࡼ࠺࡞≧ែ

ࡀ⏕ࡌ࠺ࡿ࠿ࡢ᳨ウ࡟㔜Ⅼࢆ⨨ࡁ㸪⌧≧࡟࠾࠸࡚ࡣࣔࢹࣝ࡜⮬↛᮲௳ࡢほᐹ⤖ᯝ㸦ࣅࢺࣜ

ࢼ࢖ࢺ཯ᑕ⋡ࡢ್㸧ࡀṇ☜࡟୍⮴ࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡋ࡚࠸࡞࠸㸬ࢩ࣑࣮ࣗࣞࢩࣙࣥ࡟࠾ࡅ

ࡿ ᗘ᮲௳ࡣ㸪῝ᗘ࡞࡝ࡢᇙἐ᮲௳࠾ࡼࡧ⇕ఏᑟᗘ࡞࡝ࡢᇶᮏⓗ࡞≀ᛶ᮲௳ࡔࡅ࡛࡞ࡃ㸪 ቃ⏺᮲௳ࡢタᐃ࡞࡝࡟኱ࡁࡃᙳ㡪ࡉࢀࡿ㸦Figs. 31, 32㸧㸬ࡋ࠿ࡋ㸪๓㏙ࡢ㏻ࡾ㸪࿴Ἠᒙ⩌࡛

ࡣሁ✚┅ࡢᆅୗᵓ㐀㸪⾲㠃ሁ✚≀ࡢ᭱኱ᇙἐ῝ᗘ㸪ᇶ┙ᒾࡢ✀㢮࠾ࡼࡧࡑࡢ≀ᛶࡀ༑ศ࡟

ゎ᫂ࡉࢀ࡚࠸ࡿ࡜ࡣゝ࠸㞴࠸ࡓࡵ࡛࠶ࡿ㸬ࡘࡲࡾ㸪ᮏ◊✲࡟࠾࠸࡚㸪࿴Ἠሁ✚┅ࡢ⿕⇕ࣔ

ࢹࣝ࡜⮬↛᮲௳ࡀ㢮ఝࡍࡿ᮲௳࡛࠶ࡗ࡚ࡶ㸪ᆅẆ⇕ὶ㔞࡞࡝ࡢලయⓗ࡞್ࡀ㸪ⓑள⣖ሁ✚

ᙜ᫬ࡢ࿴Ἠሁ✚┅࿘㎶࡛ࡢ≀⌮᮲௳࡜ࡋ࡚᚟ඖࡉࢀࡓ᭱㐺࡞್࡛࠶ࡿ࡜୺ᙇࡋ࡚࠸ࡿࢃࡅ

࡛ࡣ࡞࠸ࡇ࡜ࢆゝཬࡋ࡚࠾ࡃ㸬࡞࠾㸪ỿ㝆࡜ሁ✚㸪ୖ᪼࡟ࡼࡾ⏕ࡌࡿ⇕ὶ㔞ࡢኚ໬࡟ࡘ࠸

࡚㸪ᮏ◊✲࡛ࡣࡲ࡜ࡵ࡚ᇙἐຠᯝ࡜⾲⌧ࡍࡿ㸬

ࣜࢫࢺ㸯ࡢ᮲௳ࢆ౑⏝ࡋ࡚㸪࿴Ἠሁ✚┅ࡢ⿕⇕≧ែࡢࢩ࣑࣮ࣗࣞࢩࣙࣥࡢ࠸ࡃࡘ࠿ࡢ౛

ࢆ♧ࡍ㸦Fig. 34㸧㸬MTL㏆ഐ࡛ࡢ⿕⇕࡟㛵ࡋ࡚ࡣ➨㸱❶࡟࡚㸰㏻ࡾࡢゎ㔘ࢆᥦ♧ࡋࡓࡀ㸪

ᮏࣔࢹ࡛ࣝࡣ㸪ලయⓗ࡞᳨ウࡀᐜ࡛᫆࠶ࡿሁ✚ᙜ᫬ࡢሁ✚┅ᖜࡣࡶࡗ࡜ᗈ࠿ࡗࡓሙྜࢆ௬ ᐃࡋ࡚㸪ሁ✚┅ࡢᗏ㒊ࡢᙧ≧ࢆ໭⦕㒊࠿ࡽ༡⦕㒊ࡲ࡛┤⥺ⓗ࡞ᩳ㠃࡜ࡋࡓ㸬ᵝࠎ࡞᮲௳ࢆ

ኚ໬ࡉࡏ᳨࡚ウࡋࡓ⤖ᯝ㸪100mW/m2௨ୖࡢ㧗࠸ᆅẆ⇕ὶ㔞㸪༡⦕࠿ࡽ໭⦕࡬ྥ࠿ࡗ࡚ᇙ ἐ㸪ሁ✚࡜ୖ᪼ࡢ㏿ᗘࡀᑠࡉࡃ࡞ࡾ㸪ୖ᪼ࡣ༡᪉࠿ࡽ㛤ጞࡍࡿ࡜࠸࠺᮲௳㸦Fig. 35a㸧࡟࠾

࠸࡚㸪ྠࡌ῝ᗘࡲ࡛ᇙἐࡋࡓ࡜ࡋ࡚ࡶ኱ࡁ࡞⇍ᡂᗘࡢ㐪࠸ࢆᐇ⌧࡛ࡁࡓ㸦Fig. 34. model S1,

S2, S4㸧㸬ࡲࡓ㸪ᇙἐຠᯝࡀ⏕ࡌࡿ⎔ቃୗ࡛ࡢᆅᒙࡢࣈࣟࢵࢡഴື࡟ࡼࡿ⿕⇕ࣔࢹࣝࡶసᡂ

ࡋࡓ㸦Fig. 34. model S6㸧㸬ࡑࡢ௦⾲ⓗ࡞ࣔࢹࣝS2࠾ࡼࡧS6ࡢ໭⦕࣭༡⦕࡛ࡢᇙἐࣉࣟࢭ ࢫࢆ♧ࡋࡓ㸦Figs. 35, 36㸧㸬㸲ࡘࡢࣔࢹࣝ㸦Fig. 34㸧࡜ᇙἐຠᯝࡢ⏕ࡌ࡞࠸ᐃᖖ≧ែ࡛ࡢ

⿕⇕ᚋ࡟ࣈࣟࢵࢡഴືࡀ⏕ࡌࡿࣔࢹࣝࡢィ㸳ࡘࡢ᮲௳࡟࠾࠸࡚㸪ࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡ࡢ༡

໭ኚ໬ࢆẚ㍑ࡋࡓ㸦Fig. 37㸧㸬ࡍࡿ࡜㸪ᇙ✚࣭ୖ᪼㏿ᗘࡢ㐪࠸࡟ࡼࡿࣔࢹࣝS1㸪S2࠾ࡼࡧ S4࡛ࡣ┤⥺࠿ࡽⱝᖸୖ࡟ฝ㸪ࣈࣟࢵࢡഴືࢆ௬ᐃࡋࡓࣔࢹࣝ S6࡜㉥࠸ኴ⥺ࡢࣛ࢖࡛ࣥࡣ

ୗ࡟ฝ࡜࠸࠺᫂☜࡞㐪࠸ࡀ⏕ࡌࡓ㸬S6ࡸFig. 37ࡢ㉥⥺ࡢࡼ࠺࡟㸪ᇙ✚ᚋ࡟ఱࡽ࠿ࡢཎᅉ

࡛⏕ࡌࡓ༡໭᪉ྥࡢ୍ᐃゅᗘࡢഴືࢆ௬ᐃࡋࡓሙྜ㸪ᙜ↛༡໭ࡢ⇍ᡂᗘࡢᕪࡣ⏕ࡌࡿ㸬ࡋ

࠿ࡋ㸪Fig. 37ࡢ㉥⥺࡛♧ࡉࢀࡿ࡜࠾ࡾ㸪ᐃᖖ≧ែ࡛ࡢ⿕⇕ࡢሙྜ㸪୍ᵝ࡞ഴື࠾ࡼࡧഴື

ゅᗘࡀMTLഃ࡯࡝ῶᑡࡍࡿ≧ἣ࡛ࡣ㸪༡⦕࠿ࡽ໭⦕࡬ࡢ཯ᑕ⋡ࡢኚ໬⋡ࡣ㧗཯ᑕ⋡࡯࡝㧗 ࡃ࡞ࡿ࡜࠸࠺⤖ᯝࡀᚓࡽࢀࡿ㸬ࡇࢀࡣ㸪ࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡ࡢ ᗘ࡟ᑐࡍࡿኚ໬⋡ࡀ㸪཯

ᑕ⋡ࡀ㧗࠸࡯࡝኱ࡁ࠸ࡇ࡜ࡀ㉳ᅉࡍࡿ㸬ࡼࡗ୍࡚ᐃゅᗘࡢഴື࡛ࡣ㸪໭⦕┦࡟࠾࠸࡚᭱ࡶ

཯ᑕ⋡ࡢኚ໬ࡀ኱ࡁ࠸ࡇ࡜࡟࡞ࡾ㸪༡໭᪉ྥࡢ㊥㞳࡜཯ᑕ⋡ࡢ㛵ಀࡣཎ⌮ⓗ࡟⥺ᙧ࡛ࡣ࡞

ࡃୗ࡟ฝ࡜࡞ࡿࡇ࡜ࡀ♧၀ࡉࢀࡿ㸬ࡉࡽ࡟㸪ᮏ◊✲ࡢࣈࣟࢵࢡഴືࣔࢹࣝS6࡟ࡼࡾ㸪ᇙἐ

%Ro 0.6-0.8 0.8-1.0 1.0-1.2 1.4-1.6 1.6-1.8 1.8-2.0 2.0-2.2 2.2-2.4 2.4-2.6 2.6-2.8 2.8-3.0 3.0-3.20.4-0.60.2-0.4 3.2-3.4 3.4-3.61.2-1.4

N–S direction N–S direction

depth depth

bottom 27 km 1096Υ94 mW/m2 (HF 121 mW/m2) 㼎㼡㼞㼕㼍㼘㻌㼐㼑㼜㼠㼔㻦㻌6.0 km bottom 20 km 709Υ63 mW/m2 (HF 123 mW/m2) 㼎㼡㼞㼕㼍㼘㻌㼐㼑㼜㼠㼔㻦㻌5.0 km

bottom 27 km 750Υ59.5 mW/m2 (HF 86.5 mW/m2) 㼎㼡㼞㼕㼍㼘㻌㼐㼑㼜㼠㼔 㻺㻦㻌5.0 km, S: 3.0 km

NS S1 S2 S4 S6

present MTL after Yokokura et al. (1996)

bottom 27 km 1055Υ90 mW/m2 (HF 117 mW/m2) 㼎㼡㼞㼕㼍㼘㻌㼐㼑㼜㼠㼔㻦㻌6.0 km

Fig. 34. Comparisons of thermal models S1, S2, S4, and S6 for the Izumi sedimentary basin in the N–S direction. Terrestrial heat flow (HF) depends on heat flux of a bottom boundary and heat production of the sediment and basement rocks. Gradation of colors from green to dark yellow represents difference of vitrinite reflectance ranging from 0.2%Ro to 3.6%Ro.

?

71 Ma65 Ma60 Ma

2 km

0 km 4 km 6 km 8 km 10 km

time

%Ro 0.6-0.8 0.8-1.0 1.0-1.2 1.4-1.6 1.6-1.8 1.8-2.0 2.0-2.2 2.2-2.4 2.4-2.6 2.6-2.8 2.8-3.0 3.0-3.20.4-0.60.2-0.4 3.2-3.4 3.4-3.61.2-1.4

N–S direction

depth

depth depth

depth

a c b d

2 km

0 km 4 km 6 km 8 km 10 km

N–S direction

0 km3 km6 km9 km

exposure surfaceburial pass basement boundarybasin surface

NS

model S2 Timing of maximum depth

NS NS

ithotherm ithochronous lines

50Υ10Υ

2 km

0 km 4 km 6 km 8 km 10 km 2 km

0 km 4 km 6 km 8 km

N–S direction

0 km3 km6 km9 km

0 km3 km6 km9 km

Timing of uplift and deformation

Ќ c

Ќ d b Ѝ

After uplift and deformation

contour interval

Fig. 35. Burial conditions and time snapshots of the isotherm and vitrinite maturation distribution of the Model S2 (difference of the subsidence and uplift rate and timing).

71 Ma65 Ma60 Ma

depth

2 km

0 km 4 km 6 km 8 km 10 km

depth

2 km

0 km 4 km 6 km 8 km 10 km

time

71 Ma65 Ma60 Ma

time

71 Ma65 Ma60 Ma

time

71 Ma65 Ma60 Ma

time

%Ro 0.6-0.8 0.8-1.0 1.0-1.2 1.4-1.6 1.6-1.8 1.8-2.0 2.0-2.2 2.2-2.4 2.4-2.6 2.6-2.8 2.8-3.0 3.0-3.20.4-0.60.2-0.4 3.2-3.4 3.4-3.61.2-1.4

Northern margin Northern margin Southern margin Southern margin Fig. 36. Comparison of the burial histories in Model S2 (difference of the subsidence and uplift rate and timing) and Model S6 (block tilting after general heating).

S2 S6

S2 S6

ຠᯝࡢ⏕ࡌࡿࡼ࠺࡞㠀ᐃᖖ≧ែ࡛ࡢ⿕⇕࡟࠾࠸࡚ࡶᐃᖖ≧ែ⿕⇕࡜ྠᵝ࡟ୗ࡟ฝࡢഴྥ࡜

࡞ࡿࡇ࡜ࡀ♧ࡉࢀࡓ㸬ࡍ࡞ࢃࡕ㸪༡໭ࡢኚ໬ࡀ༡໭఩⨨࡜⥺ᙧ࡟࡞ࡿࡓࡵ࡟ࡣ㸪ഴືゅᗘ ࡀMTLഃ࡯࡝ቑຍࡍࡿࡼ࠺࡞㸪ୖ࡟ฝࡢ᩿㠃ᙧ≧ࢆ࿴Ἠሁ✚┅ࡀ♧ࡍሙྜࡔࡅ࡛࠶ࡿ㸬ࡋ

࠿ࡋ㸪ሁ✚┅ࡢ༡໭᩿㠃ࡣ㸪ୖ࡟ฝࡼࡾࡴࡋࢁ┤⥺ⓗࡲࡓࡣୗ࡟ฝࡢᙧ≧࡜⪃࠼ࡽࢀ࡚࠸

ࡿ㸦౛࠼ࡤ㸪ఀ⸨࡯࠿, 1996㸧㸬ᮏ◊✲㸦➨㸲❶㸧࠿ࡽ᥎ᐃࡉࢀࡓ࿴Ἠሁ✚┅ࡢⓎ㐩㐣⛬࡜

ྠᵝࡢᶓࡎࢀᘬᙇሙ࡛ᙧᡂࡋࡓሁ✚┅࡛ࡣ㸪ሁ✚┅ഃ㠃࡛ࡢୗ࡟ฝࡢ⦆ࡸ࠿࡞᩿ᒙ㠃ࡢⓎ

㐩ࢆ≉ᚩ࡜ࡋ࡚࠾ࡾ㸦Fig. 25B㸸Wu et al. 2009㸧㸪ࢧࣥࢻࣔࢹࣝ࠾ࡼࡧ⮬↛ࡢሁ✚┅࡜ࡶ

᩿㠃ᙧ≧ࡣࡋࡤࡋࡤୗ࡟ฝࡢ᩿㠃ࡀ♧ࡉࢀ࡚࠸ࡿ㸦Wu et al. 2009㸹Dooley and Schreurs, 2012㸧㸬ࡍ࡞ࢃࡕ㸪࿴Ἠᒙ⩌ࡢࣈࣟࢵࢡഴື࡟ࡼࡿ༡໭ࡢ⿕⇕≧ែࡢ㐪࠸࡟ࡼࡿ཯ᑕ⋡ࡢ༡

໭ኚ໬࡛ࡣ㸪ᮏ◊✲࡛ᚓࡽࢀࡓ༡໭᪉ྥࡢኚ໬ࡢ⥺ᙧⓗኚ໬ࢆㄝ᫂ࡍࡿࡇ࡜ࡣ࡛ࡁ࡞࠸㸬

௚᪉㸪༡໭࡛ࡢỿ㝆ᵝᘧࡢ㐪࠸࡟ࡼࡿᇙ✚ຠᯝࣔࢹ࡛ࣝࡣ㸪ሁ✚┅ࡢᗏ㒊ࡢᙧ≧ࢆ┤⥺ⓗ

࡞ᩳ㠃࡜ࡋࡓሙྜ࡟཯ᑕ⋡ࡢ༡໭㊥㞳࡟ࡼࡿኚ໬ࡣ┤⥺ⓗࡲࡓࡣୖ࡟ฝ࡜࡞ࡾ࠺ࡿ᮲௳ࡀ Ꮡᅾࡍࡿࡇ࡜ࡀࣔࢹࣝ࡟ࡼࡾ♧၀ࡉࢀࡓ㸬MTL㏆ഐࡢ⿕⇕㐣⛬࡟㛵ࡋ࡚ࡣ㸪ᮏࣔࢹ࡛ࣝ⪃

࠼ࡿࡍ࡭࡚ࡢࢣ࣮ࢫࡀ༑ศ࡞᳨ウࡉࢀࡓ࡜ࡣゝ࠼࡞࠸ࡀ㸪ᑡ࡞ࡃ࡜ࡶ࿴Ἠᒙ⩌໭⦕㒊࠿ࡽ

୺㒊┦࡟࠿ࡅ࡚ࡢ᭷ᶵ≀⇍ᡂኚ໬ࡢ኱ࡲ࠿࡞≉ᚩࡀᇙἐຠᯝࣔࢹ࡛ࣝ෌⌧ྍ⬟࡛࠶ࡿࡇ࡜

ࡣ᫂ࡽ࠿࡜࡞ࡗࡓ㸬ࡼࡗ࡚㸪ᩘ್ࣔࢹࣝ࡟ࡼࡿ⿕⇕ࡢ᳨ウ࡛ࡣ㸪࿴Ἠᒙ⩌ࡢ༡໭᪉ྥࡢ⿕

⇕ഴྥࡢせᅉࡣ㸪ሁ✚┅ࡢ༡໭᪉ྥ࡟⏕ࡌࡓᇙ✚࣭ୖ᪼㏿ᗘࡢ㐪࡛࠶ࡿ࡜⤖ㄽࡉࢀࡿ㸬

calculated Ro (%)

distance from the northern margin of the Izumi basin (km)

Basin thermal simulation Ro in N-S direction

y = −0.126x + 1.73

S1

S2 S4 S6

steady state heat condition for a long time (20–30 m.y.) before block tilting.

Rm in N-S direction Models

0 1 2 3 4 5 6 7 8 9 10

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Fig. 37. Variations in N–S-oriented vitrinite reflectance values (Ro) of Models S1, S2, S4, S6, and steady state heating condition, compared to distance from the northern marginal unconformity.

Note that differental subsidence and uplift rates is a convex trend

in Models S1, S2, and S4, but block tilting after general heating is

downward-convex trend in Models S6 and red line.

㸴ࡲ࡜ࡵ

࿴Ἠᒣ⬦ᆅᇦࡢୖ㒊ⓑள⣔࿴Ἠᒙ⩌࡟࠾࠸࡚㸪ሁ✚≀ࡢ᭷ᶵ≀⇍ᡂᣦᶆ࡛࠶ࡿࣅࢺࣜࢼ

࢖ࢺ཯ᑕ⋡㸪࢔ࣃࢱ࢖ࢺࣇ࢕ࢵࢩ࣭ࣙࣥࢺࣛࢵࢡᖺ௦ࡸ᪤ሗᖺ௦㸪⇕ᣑᩓࡢᩘ್ࣔࢹࣝࢆ

⏝࠸࡚㸪ሁ✚┅ࡢ⿕⇕ྐࢆ᚟ඖࡋࡓ㸬࿴Ἠᒣ⬦ᆅᇦ࡛ࡣ㸪ሁ✚┅ࡢ໭⦕㒊࡯࡝᭷ᶵ≀⇍ᡂ ࡀ㐍ࡴ኱ᒁⓗ࡞ഴྥࡀ㸪ࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡࠾ࡼࡧRock-Eval Tmax࡛☜ㄆࡉࢀࡓ㸬࿴Ἠ ᒣ⬦ᆅᇦす㒊࠾ࡼࡧ୰㒊ࡢ࿴Ἠᒙ⩌࡟࠾ࡅࡿ➼⇍ᡂ㠃ࡣ㸪໭⦕ࡢᇶ┙୙ᩚྜ࡟ᖹ⾜࡞ᮾ໭

ᮾ―す༡す㸦ᴫࡡN78°E᪉ྥ㸧ࡢ㉮ྥࡢ⣙19ᗘ༡ഴᩳ࡛࠶ࡾ㸪ࡑࡢ⇍ᡂ໙㓄ࡣ⣙0.400%

㸭km࡜ぢ✚ࡶࡽࢀࡓ㸬࿴Ἠᒙ⩌ࡢ≉ᚩⓗ࡞ ᗘᵓ㐀ࡢせᅉ࡜ࡋ࡚㸪ሁ✚ᚋࡢMTLࢆ㍈࡜

ࡋࡓᆅᒙࡢ༡໭ഴື㸪࿴Ἠᒙ⩌ศᕸᇦࡢ໭᪉࡟኱つᶍ⇕※ࡀᏑᅾࡋࡓྍ⬟ᛶ㸪࠾ࡼࡧሁ✚

┅ᇙἐ㐣⛬࡟㛵㐃ࡋࡓ༡໭ࡢሁ✚㏿ᗘࡢ㐪࠸࡟ࡼࡿ ᗘᵓ㐀ࡢ」㞧໬ࡀ⏕ࡌࡓྍ⬟ᛶࡢ㸱 ࡘࢆ௬ᐃࡋࡓ㸬

࿴Ἠᒙ⩌ࡢ໭⦕㒊ࢆྵࡴ㡿ᐙ̿࿴Ἠᖏ࡟࠾࠸࡚㸪ࢪࣝࢥ࣭ࣥ࢔ࣃࢱ࢖ࢺࡢࣇ࢕ࢵࢩ࣭ࣙࣥ

ࢺࣛࢵࢡᖺ௦ࢆ ᐃࡋࡓ㸬ࡑࡢ⤖ᯝ࡜᪤Ꮡࡢ◊✲ࡢᨺᑕᖺ௦ࢆࡶ࡜࡟ᙜᆅᇦࡢ෭༷ྐࢆ᥎ ᐃࡋࡓ㸬࿴Ἠᒣ⬦ᆅᇦࡢ࿴Ἠᒙ⩌㸪Ἠ༡ὶ⣠ᒾ㢮㸪࠾ࡼࡧᑼ࢔ࢲ࣓ࣟᒾࡢ⇕ᖺ௦Ꮫⓗࢹ

࣮ࢱ࠿ࡽࡣ㸪ᮏᆅᇦࡣ㸱ࡘࡢᆅ㉁༢ඖࢆྵࡴ༢୍ࡢࣈࣟࢵࢡ࡛ࡢ෭༷ྐ࣭ୖ᪼ྐࢆ᥎ᐃࡍ

ࡿࡇ࡜ࡣᅔ㞴࡛࠶ࡾ㸪෭༷ྐࡢ㐪࠸࡟ࡼࡾᮾすᛶࡢ᩿ᒙ࣭᩿ᒙ⩌࡛⏬ࡉࢀࡓ㸱ࡘࡢᆅ㉁ࣈ

ࣟࢵࢡ࡟༊ศࡍࡿࡇ࡜ࡀ࡛ࡁࡿ࡜ุ᩿ࡉࢀࡓ㸬ࡲࡓ㸪⇕ᖺ௦Ꮫⓗゎ㔘࠿ࡽ࿴Ἠᒙ⩌໭᪉ࡢ

኱つᶍ⇕※ࡢᏑᅾࡣྰᐃࡉࢀࡓ㸬࿴Ἠሁ✚┅ࡢᙧᡂ࡟㛵ࡋ࡚㸪໭⦕࡛୙㐃⥆࡞㞜⾜≧ࡢ᩿

ᒙ⩌ࢆక࠺࿴Ἠሁ✚┅ࡢⓎ㐩ࡀ♧၀ࡉࢀ㸪ᶓࡎࢀᘬᙇሙ࡛ሁ✚┅ࡀᙧᡂࡋࡓ࡜ุ᩿ࡉࢀࡓ㸬

࿴Ἠᒣ⬦ᮾ㒊ᆅᇦ࡛ࡣ㸪࿴Ἠᒙ⩌ࡢᇙἐ࠿ࡽୖ᪼࡬ࡢኚ㑄ࡀ 5 m.y.௨ෆࡢ▷ᮇ㛫࡛⏕ࡌ㸪

68.9–66.2 Maᮇ㛫࡟୺࡞⿕⇕ࢆཷࡅࡓྍ⬟ᛶࡀ㧗࠸ࡇ࡜ࡀࣅࢺࣜࢼ࢖ࢺ཯ᑕ⋡ࡢࣔࢹࣝィ

⟬ࡼࡾ♧၀ࡉࢀࡓ㸬ࡇࢀࡣ㸪ᕷᕝ࡯࠿㸦1981㸧ࡀ⪃᱌ࡋࡓ㸪ሁ✚┅୰ᚰࡢᮾ࡬ࡢ⛣ື࡜ᪧ ሁ✚┅୰ᚰࡢୖ᪼ࢆ⧞ࡾ㏉ࡍ࿴Ἠሁ✚┅ࡢᮾ㐍㐣⛬ࢆ཯ᫎࡋࡓࡶࡢ࠿ࡶࡋࢀ࡞࠸㸬

ሁ✚ᚋࡢMTLࢆ㍈࡜ࡋࡓᆅᒙࡢ༡໭ഴື㸪࠾ࡼࡧሁ✚┅ᇙἐ㐣⛬࡟㛵㐃ࡋࡓ༡໭ࡢሁ✚

㏿ᗘࡢ㐪࠸࡟ࡼࡿ ᗘᵓ㐀ࡢ」㞧໬࡛⏕ࡌࡿ ᗘᵓ㐀࡜᭷ᶵ≀⇍ᡂ≧ែࢆලయⓗ࡟᳨ウࡍ

ࡿࡓࡵ㸪ᩘ್ࢩ࣑࣮ࣗࣞࢩࣙࣥࢆ⾜ࡗࡓ㸬ࡇࡢࣔࢹࣝࡣHutchison㸦1985㸧ࡢ⌮ㄽࢆᇶ࡟㸪 ሁ✚┅ࡢୖ᪼ࡸᾏᗏ㠃ࡢỿ㝆࡟ᑐᛂࡍࡿࡼ࠺࡟ኚ᭦ࢆຍ࠼ࡓ㸬ᇙἐຠᯝࡢᙳ㡪ࢆ᳨ウࡍࡿ

ࡓࡵࡢࢩ࣑࣮ࣗࣞࢩࣙࣥ⤖ᯝ࠿ࡽ㸪ᛴ㏿࡞ỿ㝆ࡣࡑࡢỿ㝆㏿ᗘ࡟ᛂࡌ࡚⇕ὶ㔞࡜ᆅ ໙㓄 ࡢῶᑡࢆࡶࡓࡽࡍࡀ㸪ᛴ㏿࡞ୖ᪼࡟ࡘ࠸࡚ࡣ⤖ᯝⓗ࡟ୖ᪼㏿ᗘࡀ኱ࡁ࠸࡯࡝ ᗘᒚṔࡀప  ໬ࡍࡿࡇ࡜ࡀ♧၀ࡉࢀࡓ㸬ࡲࡓ㸪ᾏᗏ㠃ࡢỿ㝆ࡣ᭱኱ỿ㝆᫬ࡢ ᗘ࠾ࡼࡧୖ᪼᫬ࡢ ᗘ

≧ែࢆࡼࡾపୗࡉࡏࡿຠᯝࡀ࠶ࡿࡇ࡜ࡀ♧၀ࡉࢀࡓ㸬ሁ✚┅ࡢලయⓗ࡞ᇙἐࣔࢹ࡛ࣝࡣ㸪 ሁ✚࡜ୖ᪼ࡢ㏿ᗘࡢ㐪࠸࡛ሁ✚┅ࡢ༡໭᪉ྥ࡟⇍ᡂ໙㓄ࢆᙧᡂ࡛ࡁࡓ㸬ሁ✚┅᩿㠃ࡀ┤⥺

ⓗ࡟༡᪉࡟῝ࡃ࡞ࡿሙྜ㸪༡໭㊥㞳࡟ᑐࡍࡿኚ໬ഴྥࡣୖ࡟ฝࡲࡓࡣ┤⥺ⓗ࡜࡞ࡗࡓ㸬௚

᪉㸪༡໭ഴືࣔࢹ࡛ࣝࡶ༡໭᪉ྥ࡟⇍ᡂ໙㓄ࡀ⏕ࡌࡿࡀ㸪ࡑࡢኚ໬ഴྥࡣཎ⌮ⓗ࡟ୗ࡟ฝ

࡛࠶ࡿࡇ࡜ࡀ♧၀ࡉࢀࡓ㸬ࡼࡗ࡚㸪࿴Ἠᒙ⩌ࡢ༡໭᪉ྥࡢ⿕⇕ഴྥࡢせᅉࡣ㸪ሁ✚┅ࡢ༡

໭᪉ྥ࡟⏕ࡌࡓᇙ✚࣭ୖ᪼㏿ᗘࡢ㐪࡛࠶ࡿ࡜⤖ㄽࡉࢀࡿ㸬

ドキュメント内 ࿴Ἠᒣ⬦ᆅᇦ࡟࠾ࡅࡿ㡿ᐙ̿࿴Ἠᖏࡢ (ページ 100-115)

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