Petrochemical characteristics of Permo‐Triassic granitoids from five regions (i) Mung Loei, (ii) Phu Thap Fah – Phu Thep, (iii) Phetchabun, (iv) Nakon Sawan – Lobburi, and (v) Rayong – Chantaburi along the Loei Fold Belt (LFB), northeastern Thailand were studied. The LFB is a north–south trending 800 km fold belt that hosts several gold and base‐metal deposits. The granitoids consist of monzogranite, granodiorite, monzodiorite, tonalite, quartz‐syenite, and quartz‐rich granitoids. These are composed of quartz, plagioclase, and K‐feldspar with mafic minerals such as hornblende and biotite. Accessory minerals, such as titanite, zircon, magnetite, ilmenite, apatite, garnet, rutile, and allanite are also present. Magnetic susceptibilities in the SI unit of granitoids vary from 6.5 × 10⁻³ to 15.2 × 10⁻³ in Muang Loei, from 0.1 × 10⁻³ to 29.4 × 10⁻³ in Phu Thap Fah – Phu Thep, from 2.7 × 10⁻³ to 34.6 × 10⁻³ in Petchabun, from 2.4 × 10⁻³ to 14.1 × 10⁻³ in Nakon Sawan – Lobburi, and from 0.03 × 10⁻³ to 2.8 × 10⁻³ in Rayong – Chantaburi. Concentration of major elements suggests that these intermediate to felsic plutonic rocks have calc‐alkaline affinities. Concentration of REE of the granitoids normalized to chondrite displays moderately elevated light REE (LREE) and relatively flat heavy (HREE) patterns, with distinct depletion of Eu. Rb versus Y/Nb and Nb/Y tectonic discrimination diagrams illustrate that the granitoids from Muang Loei, Phu Thap Fah – Phu Thep, Phetchabun, Nakon Sawan – Lobburi, and Rayong – Chantaburi formed in continental volcanic‐arc setting. New age data from radiometric K‐Ar dating on K‐feldspar from granodiorite in Loei and Nakhon Sawan areas yielded 171 ± 3 and 221 ± 5 Ma, respectively. K‐Ar dating on hornblende separated from diorite in Lobburi yielded 219 ± 8 Ma. These ages suggest that magmatism of Muang Loei occurred in the Middle Jurassic, and Nakon Sawan – Lobburi occurred in Late Triassic. Both Nb versus Y and Rb versus (Y + Nb) diagrams and age data indicate that Nakon Sawan – Lobburi granitoids intruded in Late Triassic at Nong Bua, Nakon Sawan province and Khao Wong Phra Jun, Lobburi province in volcanic arc setting. Muang Loei granitoids at the Loei province formed later in Middle Jurassic also in volcanic arc setting. The negative δ³⁴S_CDT values of ore minerals from the skarn deposit suggest that the I‐type magma has been influenced by light biogenic sulfur from local country rocks. The Au‐Cu‐Fe‐Sb deposits correlate with the magnetite‐series granitoids in Phetchabun, Nakon Sawan – Lobburi and Rayong – Chantaburi areas. Metallogeny of the Au and Cu‐Au skarn deposits and the epithermal Au deposit is related to adakitic rocks of magnetite‐series granitoids from Phetchabun and Nakon Sawan areas. All mineralizations along the LFB are generated in the volcanic arc related to the subduction of Paleo‐Tethys. The total Al (^TAl) content of biotite of granitoids increases in the following order: granitoids associated with Fe and Au deposit < with Cu deposit < barren granitoids. X_Mg of biotite in granitoids in Muang Loei indicates the crystallization of biotite in magnetite‐series granitoids under high oxygen fugacity conditions. On the other hand, low X_Mg (<0.4) of biotite in magnetite‐series granitoids in Phu Thap Fah – Phu Thep and Rayong – Chantaburi indicates a reduced environment and low oxygen fugacity, associated with Au skarn deposit (Phu Thap Fah) and Sb‐Au deposit (Bo Thong), respectively. The magnetite‐series granitoids at Phu Thap Fah having low magnetic susceptibilities and low X_Mg of biotite were formed by reduction of initially oxidizing magnetite‐series granitic magma by interaction with reducing sedimentary country rocks as suggested by negative δ³⁴S_CDT values.

中文翻译：

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泰国东北部黎伊褶皱带的花岗岩类岩石化学

五个地区（i）蒙黎，（ii）富塔法–富披，（iii）碧差汶，（iv）Nakon Sawan – Lobburi和（v）Rayong – Chantaburi的五个地区的Permo–Triassic花岗岩的石化特征对泰国东北部的Belt（LFB）进行了研究。LFB是一条北北走向的800 km褶皱带，拥有数个金矿和贱金属矿床。花岗岩类由辉长花岗岩，花岗闪长石，蒙脱辉闪石，方钠石，石英榴辉岩和富含石英的花岗岩组成。它们由石英，斜长石和钾长石与黑角质矿物和黑云母等镁铁质矿物组成。还存在辅助矿物，例如钛矿，锆石，磁铁矿，钛铁矿，磷灰石，石榴石，金红石和尿石。花岗岩类SI单位的磁化率从6.5×10 ^-3到15.2×10不等^-3在芒黎，从0.1×10 ^-3到29.4×10 ^-3的Phu同塔白花-富THEP，从2.7×10 ^-3到34.6×10 ^-3在碧差汶，从2.4×10 ^-3到14.1× Nakon Sawan – Lobburi中的10 ^-3，从0.03×10 ^-3到2.8×10 ^-3在罗勇府–尖竹汶府。主要元素的浓度表明这些中等至长英质的深成岩具有钙碱性亲和力。标准化为球粒陨石的花岗岩的REE浓度显示出适度升高的轻REE（LREE）和相对平坦的重（HREE）模式，且Eu明显耗竭。Rb对Y / Nb和Nb / Y的构造判别图表明，来自Muang Loei，Phu Thap Fah – Phu Thep，Phetchabun，Nakon Sawan – Lobburi和Rayong – Chantaburi的花岗岩是在大陆火山弧环境中形成的。来自黎府和那空沙旺地区的花岗闪长岩中钾长石的放射性K-Ar年代测定的新年龄数据分别为171±3和221±5 Ma。Lobburi闪长岩与闪长岩分离的K-Ar测年结果为219±8 Ma。这些年龄表明，孟黎的岩浆作用发生在侏罗纪中期，而纳孔·萨旺-罗布布里的岩浆作用发生在三叠纪晚期。Nb与Y的关系图和Rb与（Y + Nb）的关系图和年龄数据均表明，Nakon Sawan – Lobburi花岗岩类在晚三叠世侵入了Nakon Sawan省的Nong Bua和Lobburi省的Khao Wong Phra Jun，处于火山弧环境中。黎府的孟黎花岗岩体后来在中侏罗世也形成了火山弧。负δ 黎府的孟黎花岗岩体后来在中侏罗世也形成了火山弧。负δ 黎府的孟黎花岗岩体后来在中侏罗世也形成了火山弧。负δ矽卡岩矿床的矿石矿物具有³⁴ S _CDT值，表明I型岩浆受到了当地乡村岩石中的轻生物成因硫的影响。Au-Cu-Fe-Sb矿床与Phetchabun，Nakon Sawan – Lobburi和Rayong – Chantaburi地区的磁铁矿系列花岗岩有关。Au和Cu-Au矽卡岩矿床的成矿作用以及超热的Au矿床与Phetchabun和Nakon Sawan地区的磁铁矿系列花岗岩的埃达克岩石有关。LFB沿线的所有矿化都在与古特提斯俯冲有关的火山弧中产生。花岗岩类黑云母的总Al（^T Al）含量按以下顺序增加：与Fe和Au沉积有关的花岗岩<与Cu沉积<贫瘠的花岗岩。X_镁孟黎花岗岩体中黑云母的数量表明高氧逸散条件下磁铁矿系列花岗岩中黑云母的结晶。另一方面，Phu Thap Fah – Phu Thep和Rayong – Chantaburi的磁铁矿系列花岗岩中黑云母的X _Mg低（<0.4），这表明环境减少，氧逸度低，与Au矽卡岩沉积（Phu Thap Fah）有关。锑金矿床（博通）。在富同塔华氏具有低磁化率和低X磁铁矿系列花岗岩_镁黑云母都是由还原的由相互作用与减少沉积围岩由负δ建议最初氧化磁铁矿系列花岗岩浆形成^34个小号_CDT值。