Abstract ........................................................ 5
Introduction .................................................... 6
Acknowledgments ................................................. 7
Chapter 1. GEOPHYSICAL DATA ON MANTLE ANOMALIES ................. 8
Chapter 2. TECTONIC MODELS ..................................... 14
2.1 Northwestern Pacific ...................................... 15
2.1.1 Plates of Pacific Ocean ............................ 15
2.1.1.1 Kula-Izanagi plate ............................. 16
2.1.1.2 Pacific plate .................................. 17
2.1.2 Philippine Sea plate ............................... 20
2.1.3 Okhotsk Sea tectonic unit .......................... 24
2.1.4 Sea of Japan between Okhotsk Sea and Philippine
Sea plates ......................................... 31
2.2 East and Central Asia ..................................... 33
2.2.1 Jurassic through Early Cretaceous: closure of
Mongolia-Okhotsk Ocean ............................. 33
2.2.2 Continental margin of East Asia .................... 34
2.2.3 Compressional and extensional tectonics ............ 36
2.3 Summary ................................................... 39
Chapter 3. MAGMATIC AND TECTONIC EVENTS ........................ 41
3.1 Selection of isotopic ages ................................ 41
3.2 Mesozoic .................................................. 43
3.2.1 Middle Jurassic - Early Cretaceous events of
180-113 Ma ......................................... 44
3.2.1.1 Central Asia ................................... 45
3.2.1.2 Eastern margin of Eurasia ...................... 46
3.2.1.3 Eurasia-Pacific convergent zone ................ 49
3.2.2 Middle - Late Cretaceous events of 110-65 Ma ....... 51
3.2.2.1 Central Asia ................................... 52
3.2.2.2 Eastern margin of Eurasia ...................... 52
3.2.2.3 Eurasia-Pacific convergent zone ................ 53
3.3 Early Cenozoic ............................................ 58
3.3.1 Paleocene-Early Eocene events of 65-50 Ma .......... 58
3.3.1.1 Central Asia ................................... 58
3.3.1.2 Pacific-Eurasia convergent zone ................ 60
3.3.2 Middle-Eocene events of 48-43 Ma ................... 62
3.3.2.1 Central Asia ................................... 62
3.3.2.2 Pacific-Eurasia convergent zone ................ 62
3.4 Middle Cenozoic ........................................... 63
3.4.1 Central Asia ....................................... 63
3.4.2 Pacific-Eurasia convergent zone .................... 65
3.5 Late Cenozoic ............................................. 72
3.5.1 Magmatic periodicity at the North East Japan
Volcanic Arc (NEJVA) as a basis for comparative
analysis of Late Cenozoic events ................... 72
3.5.2 Oligocene-Miocene boundary: events at ca. 23 Ma .... 76
3.5.3 Early Miocene events of 22-17 Ma ................... 77
3.5.4 Middle Miocene through Pliocene events of 16-2 Ma .. 78
3.5.4.1 Pacific-Eurasia convergent zone ................ 78
3.5.4.2 Central and South Asia ......................... 81
3.5.5 Latest Pliocene - Quaternary <2 Ma ................. 83
3.5.5.1 Initiation of the latest Pliocene -
Quaternary stage ............................... 83
3.5.5.2 Cessation of volcanic activity ................. 84
3.5.5.3 Volcanic episodicity ........................... 87
3.6 Summary ................................................... 90
Chapter 4. GEODYNAMIC APPLICATIONS OF MAGMATIC SEQUENCES ....... 93
4.1 Hypothetical mantle processes: role of subduction in
creating high velocity regions ............................ 93
4.2 Origin of the East Asian anomalous mantle region .......... 95
4.3 Reconstructions ........................................... 98
4.3.1 General statement for tectonic and magmatic
evidence on transition from the Mongolia-Okhotsk
to Kula-Izanagi and Pacific slab subduction ........ 98
4.3.2 Particularities of Paleocene; Early Eocene
tectonics and magmatism ............................ 99
4.3.3 Remarkable magmatic impulse at about 30 Ma ........ 102
4.3.4 Accretion-derived slab deformations ............... 103
4.3.5 Oscillatory rotating stress field of the past
47 Ma ............................................. 104
4.3.6 Back-arc extension: models, style at Sea of
Japan ............................................. 106
4.3.7 Successive change of magmatic sources beneath Sea
of Japan and Tatar Strait ......................... 107
4.3.8 Timing of mid-continental rifting in South
Siberia: comparisons with rifted Pacific-Eurasia
convergent zone ................................... 111
4.4 Summary .................................................. 113
References .................................................... 117
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