Zircon Hf‐isotope constraints on the formation of metallic mineral deposits in Thailand

Abstract

The effects of the Sibumasu–Indochina Terranes collision created several kinds of mineral deposits in Thailand, which include porphyry–skarn copper–gold, epithermal gold and antimony, orogenic gold–antimony–tungsten and tin‐tungsten mineralization among others. The deposits show a distinct spatial zonal distribution and occur in specific tectonic terranes. Combining regional geological data and ore deposit distribution data with Hf‐isotopic data of zircons in igneous rocks can be used to investigate the relationship between crustal construction processes and metallogeny. In this study, we investigated the Sukhothai Fold Belt, which is composed of quartz monzodiorite, granodiorite, syenogranite, and monzogranite of I‐ and S‐type affinities. All granitoids were analyzed for zircon U–Pb geochronology and Lu–Hf isotopic analysis. The granitoids of the Sukhothai Fold Belt yielded U–Pb zircon ages ranging from ~243 to 202 Ma, which mark the timing of subduction to the syn‐collisional stage between the Sibumasu–Indochina terranes at ~243–237 Ma and the timing of post‐collision between the Sibumasu–Indochina terranes during 230–202 Ma. In addition, an age of ~43 Ma in the south of the Sukhothai Fold Belt may indicate intrusion during the sinistral movement of the Klaeng and Mae Ping fault zones resulted from the Indian–Eurasian plate collision. The Doi Tung quartz monzodiorite provided an age of ~350 Ma as a timing of formation of the Sukhothai Fold Belt. The negative and positive initial εHf values (−8.0 to +9.2) with two‐stage depleted mantle model ages (TDMC of 2.2–0.6 Ga) of zircons from the Sukhothai Fold Belt granitoids indicate that the sources of their magma derived from partial melting of old continental crust and young oceanic crust, which probably mixed with a mantle‐derived magma. A zircon Hf‐isotope compilation including the data obtained in this study and previously reported values was used to prepare a map that allows a comparison between magmatic source and mineral deposit distribution in Thailand. The spatial distribution of Hf isotopic data reveals a distinct zonation, with initial εHf values decreasing from the east to the west, that is, from the western margin of the Indochina Terrane or the Loei Fold Belt to the Sukhothai Fold Belt, the Inthanon Zone and the Sibumasu Terrane. The magmatic source for the granitoids in the Loei Fold Belt is dominated by mantle‐derived components, as shown by positive average initial εHf values (+1.0 to +12.7), and contributed to porphyry‐related skarn copper–gold and iron and epithermal gold mineralization. In contrast, magmas in the Sibumasu Terrane and the Inthanon Zone originated from melting of old crustal materials, as indicated by mostly negative average initial εHf values (−15.1 to +0.8), and are responsible for S‐type granite‐related tin‐tungsten mineralization. The average initial εHf values (−5.0 to +11.0) from the intrusions in the Sukhothai Fold Belt suggest mixed sources, including evolved and juvenile magmatic materials, which generated the oroge...

Zircon U-Pb geochronology of the Lan Sang gneisses and its tectonic implications for the Mae Ping shear zone, NW Thailand

“…Orthogneisses, mylonitic granite, and pegmatites of the KMSZ have zircon U-Pb ages of 55-46 Ma, which may be linked to an early dextral ductile deformation phase (Kanjanapayont et al, 2012). In southeastern Thailand, magmatic zircon U-Pb ages of 55-43.3 Ma have been obtained from monzogranite and granite samples (Veeravinantanakul et al, 2021;Uchida et al, 2022). Veeravinantanakul et al (2021) interpreted 43 Ma as the timing of intrusion during the sinistral movement of the KSZ.…”

“…In southeastern Thailand, magmatic zircon U-Pb ages of 55-43.3 Ma have been obtained from monzogranite and granite samples (Veeravinantanakul et al, 2021;Uchida et al, 2022). Veeravinantanakul et al (2021) interpreted 43 Ma as the timing of intrusion during the sinistral movement of the KSZ.…”

U–Pb dating for zircons from granitic rocks in southwestern Cambodia

“…Therefore, U–Pb dating was performed for zircons of granitic rocks collected in southwestern Cambodia in this study. It should be noted that U–Pb dating for zircon particles was previously performed on some granitic bodies of southwestern Cambodia and southeastern Thailand (Chanthaburi zone) by Veeravinantanakul et al [ 9 ] and Uchida et al [ 6 ].

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Stratigraphy and geochemistry of rock salt from Maha Sarakham formation in changwat Chaiyaphum, northeastern Thailand

“…The deformation of the Khorat Plateau (clockwise rotational motion and southward displacement) Sato et al (2007) was rotated by the collision of continental between India and Eurasia (Himalaya orogeny) during early Paleocene. After these collision, the Khorat Plateau was separated into two basins, Sakon Nakhon basin in the north and Khorat basin in the south by the Phu Phan ranges lies in the NW-SE direction (El Tabakh et al, 1999;Meesook, 2000;Songtham et al, 2011;Veeravinantanakul et al, 2018).…”

“…El Tabakh et al, 1999;Qin et al, 2020;Ren et al, 2018;Tan et al, 2010;Yumuang et al, 1986;Zhang et al, 2013) 3) Deformation stage (Figure 74D), the horizontal beds of the Maha Sarakham Formation have deformed to dome structure by loading of overburden or reginal tectonic (Yumuang et al, 1986). This tectonic has collision of the Eurasia and India plates as Himalayan orogeny that cause is made rotate clockwise of Indochina plate and separation within the Khorat Plateau into Sakon Nakhon basin in the north and Khorat basin in the south by the Phu Phan ranges lies in the NW-SE direction (El Tabakh et al, 1999;Meesook, 2000;Songtham et al, 2011;Veeravinantanakul et al, 2018).…”