Tectonic and thermal evolution of Thailand in the regional context of SE Asia

Searle, Michael P.; Morley, Christopher

doi:10.1144/goth.20

Cited by 56 publications

(55 citation statements)

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“…Figure 2. Tectonic map of SE Asia [25]. Cambodia is entirely contained within the Indochina terrain bounded on the northeast by the Song Ma Suture (SMS).…”

Section: Introductionmentioning

confidence: 99%

“…Collision and convergence of the Indochina block with the Asian continent (Shan-Thai terrane in Thailand) started at ~250 Ma and culminated around the Triassic-Jurassic boundary (~210-200 Ma) with the closure of Paleotethys and the end of the Indosinian orogeny [25,26]. The Indochina terrain is composed of continental crust, which has remained intact and stable since the end of the Indosinian orogeny, and is surrounded by younger, post-Jurassic fold belts.…”

Section: Introductionmentioning

confidence: 99%

“…Known collectively as the SE Asian Volcanic Province [36][37][38] or the Central-East Asian basaltic province [8], the basalts ascended along rift structures bounded by strike-slip faults within Archean to Paleozoic terrains and were more extensive in Vietnam, Eastern Cambodia, and Southern Laos than elsewhere in the region even though no temporal and spatial correlation has been established [39]. In most areas, two separate periods of volcanism are noted: (1) an early phase consisting of [25]. Cambodia is entirely contained within the Indochina terrain bounded on the northeast by the Song Ma Suture (SMS).…”

Section: Introductionmentioning

confidence: 99%

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Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

et al. 2018

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Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon within a 12,000 km long Indo-Pacific megacryst zone. Colorless, yellow, brown, and red crystals ({100}, {101}, subordinate {211}, {1103}), with hopper growth and corrosion features range up to 20 cm in size. Zircon chemistry indicates juvenile, Zr-saturated, mantle-derived alkaline melt (Hf 0.6-0.7 wt %, Y <0.2 wt %, U + Th + REE (Rare-Earth Elements) < 600 ppm, Zr/Hf 66-92, Eu/Eu* N~1 , positive Ce/Ce* N , HREE (Heavy REE) enrichment). Incompatible element depletion with increasing Yb/Sm N from core to rim at~constant Hf suggests single stage growth. Ti-in-zircon temperatures (~570-740 • C) are lower than predicted by crystal morphology (800-900 • C) and decrease from core to rim (∆T = 10-50 • C). The δ 18 O values (4.88 to 5.01 Abstract: Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon within a 12,000 km long Indo-Pacific megacryst zone. Colorless, yellow, brown, and red crystals ({100}, {101}, subordinate {211}, {1103}), with hopper growth and corrosion features range up to 20 cm in size. Zircon chemistry indicates juvenile, Zr-saturated, mantlederived alkaline melt (Hf 0.6-0.7 wt %, Y <0.2 wt %, U + Th + REE (Rare-Earth Elements) < 600 ppm, Zr/Hf 66-92, Eu/Eu*N ~1, positive Ce/Ce*N, HREE (Heavy REE) enrichment). Incompatible element depletion with increasing Yb/SmN from core to rim at ~ constant Hf suggests single stage growth. Ti-in-zircon temperatures (~570-740 C) are lower than predicted by crystal morphology (800-900 C) and decrease from core to rim (T = 10-50 C). The  18 O values (4.88 to 5.01‰ VSMOW (Vienna Standard Mean Ocean Water)) are relatively low for xenocrysts from the zircon Indo-Pacific zone (ZIP). The 176 Hf/ 177 Hf values (+ εHf 4.5-10.2) give TDepleted Mantle model source ages of 260-462 Ma and TCrustal ages of 391-754 Ma. The source magmas reflect variably depleted lithospheric mantle with little supracrustal input. Zircon U-Pb (0.88-1.56 Ma) and (U-Th)/He (0.86-1.02 Ma) ages are older than host basalt ages (~0.7 Ma), which suggests limited residence before transport. Zircon genesis suggests Zr-saturated, Al-undersaturated, carbonatitic-influenced, low-degree partial melting (<1%) of peridotitic mantle at ~60 km beneath the Indochina terrane.

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“…Figure 2. Tectonic map of SE Asia [25]. Cambodia is entirely contained within the Indochina terrain bounded on the northeast by the Song Ma Suture (SMS).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

et al. 2018

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“…At the Indus-Tsangpo Suture in the western Himalayas and northern Indian margin, it has been constrained to early Eocene (50.5 Ma) [e.g., Rowley, 1998;Zhu et al, 2005;Green et al, 2008], but the timing in the east is less clear. However, widespread Paleocene-Oligocene metamorphism and transpression in Myanmar and west Thailand are consistent with initial coupling between West Burma and India at about 50 Ma [Morley, 2004;Searle et al, 2007;Searle and Morley, 2011], indicating that the effects of the Indian plate were being transmitted from Sundaland's margin to its interior from that time. The orientation and shear sense of the RF and KMF alone, or as a conjugate pair with the Mae Ping and Three Pagodas faults, are entirely consistent with NE directed compression caused by India coupling to West Burma, particularly when Neogene dextral slip along the Sagaing Fault is restored.…”

Section: Discussionmentioning

confidence: 71%

“…Morley [2004] proposed a period of transpression in western Thailand to explain features including long-lived and complex sinistral slip along the Mae Ping and Three Pagodas faults, Paleogene folds and thrusts, and Eocene uplift of the Khorat Plateau in east Thailand. Searle and Morley [2011] suggest that these features may be the result of India-West Burma coupling in advance of the main period of India-Asia collision.…”

Section: Tectonic Settingmentioning

confidence: 98%

The timing of strike-slip shear along the Ranong and Khlong Marui faults, Thailand

et al. 2011

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[1] The timing of shear along many important strike-slip faults in Southeast Asia, such as the Ailao Shan-Red River, Mae Ping and Three Pagodas faults, is poorly understood. We present 40 Ar/ 39 Ar, U-Pb SHRIMP and microstructural data from the Ranong and Khlong Marui faults of Thailand to show that they experienced a major period of ductile dextral shear during the middle Eocene (48-40 Ma, centered on 44 Ma) which followed two phases of dextral shear along the Ranong Fault, before the Late Cretaceous (>81 Ma) and between the late Paleocene and early Eocene (59-49 Ma). Many of the sheared rocks were part of a pre-kinematic crystalline basement complex, which partially melted and was intruded by Late Cretaceous (81-71 Ma) and early Eocene (48 Ma) tin-bearing granites. Middle Eocene dextral shear at temperatures of ∼300-500°C formed extensive mylonite belts through these rocks and was synchronous with granitoid vein emplacement. Dextral shear along the Ranong and Khlong Marui faults occurred at the same time as sinistral shear along the Mae Ping and Three Pagodas faults of northern Thailand, a result of India-Burma coupling in advance of India-Asia collision. In the late Eocene (<37 Ma) the Ranong and Khlong Marui faults were reactivated as curved sinistral branches of the Mae Ping and Three Pagodas faults, which were accommodating lateral extrusion during India-Asia collision and Himalayan orogenesis.

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Midcrustal shearing and doming in aCenozoic compressive setting along theAilaoShan‐RedRiver shear zone

Zhang

Yin

Zhang

et al. 2017

Geochem Geophys Geosyst

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The Cenozoic Xuelong Shan antiformal dome is located along the northern segment of the Ailao Shan-Red River shear zone in Yunnan, China. Subhorizontal foliation in the gneiss core is recognized, representing a broad top-to-NE shear initiated under amphibolite facies conditions and propagating into greenschist facies in the mantling schist and strike-slip shear zone. Microfabrics of crystallographicpreferred orientations (CPOs) in quartz suggest that the deformation temperatures increased with increasing structural depth from the upper crust (300-5008C) in the mantling schist to the midcrust (15 km or more, 6508C) in the gneissic core. This trend is mirrored by variations in the metamorphic grade of the syn-kinematic mineral assemblages and microstructures, which range from garnet 1 amphibole 1 biotite 1 sillimanite 1 rutile 1 feldspar in the core to garnet 1 staurolite 1 biotite 1 epidote 1 muscovite within the limb units. The dome experienced the following deformation history: (1) a broad top-to-NE shear in the subhorizontal foliation of the gneiss core during the first stage of deformation (D1); (2) opposing reverse-sense shear along the two schist limbs of the dome during contraction-related doming (D2-D3); (3) sinistral strike-slip shearing within the eastern limb (D4); and (4) extensional deformation (D5). The structural-thermal patterns suggest the antiformal dome formation was roughly coeval with top-to-NE ductile shearing in the midcrust of Tibet at 32 Ma or earlier. A major implication is that there was a phase of contractional ductile deformation in the region prior to the initiation of strike-slip deformation.

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Tectonic and thermal evolution of Thailand in the regional context of SE Asia

Cited by 56 publications

References 0 publications

Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

The timing of strike-slip shear along the Ranong and Khlong Marui faults, Thailand

Midcrustal shearing and doming in aCenozoic compressive setting along theAilaoShan‐RedRiver shear zone

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