【摘要】 基于地球化学参数及分析数据，应用热守恒方程、质量平衡定律及瑞利分馏模型等方法，通过对莺歌海盆地乐东底辟区的壳源氦气原位产率和外部通量、幔源初始氦浓度及热驱动机制等定量分析，探讨深部热流体活动背景下氦气的成因来源及运聚机制。研究结果表明：（1）乐东底辟区氦气的来源以壳源氦为主，幔源为辅。其中，研究区幔源³He/⁴He值为（0.002～2.190）×10^-6,R/R_a值为0.01～1.52，测算幔源He贡献占比为0.09%～19.84%，占比较小；而壳源贡献占比则高达80%以上。（2）壳源氦的原位⁴He产量仅为（4.10～4.25）×10^-4 cm³/g，外部4He通量则显著高值，为（5.84～9.06）×10^-2 cm³/g，表明壳源氦气以外部输入为主，推测与地层流体受大气补给以及深部岩石-水相互作用有关。（3）底辟区深部热流体活动显著影响地温场，³He初始质量体积与对应焓的比值（W）为（0.004～0.018）×10^-11 cm³/J，来自深部地幔的热贡献（XM）为7.63%～36.18%，揭示底辟热流体对幔源³He迁移具有一定的热驱动作用。（4）研究区氦气的初次运移方式以平流为主，二次运移受控于水热脱气和气液分离过程；氦气从深部至浅部的运移过程中，CO₂/³He值由1.34×10⁹升至486×10⁹，指示受到壳幔混合和脱气效应影响，存在CO₂规模性析出和³He的明显逸散。在深部热流体影响下，氦气运移聚集机制包括：深部热驱动扩散、平流释放、垂向水热脱气，浅部横向迁移、远离断裂的圈闭聚集，分压平衡、完整密闭的盖层封存等方面。更多还原

【Abstract】 Based on the geochemical parameters and analytical data, the heat conservation equation, mass balance law, Rayleigh fractionation model and other methods were used to quantify the in-situ yield and external flux of crust-derived helium, and the initial He concentration and thermal driving mechanism of mantle-derived helium, in the Ledong Diapir area, the Yinggehai Basin, in order to understand the genetic source and migration & accumulation mechanisms of helium under deep hydrothermal fluid activities. The helium in the Ledong diapir area is primarily derived from the crust and a small amount from the mantle. For mantle-derived helium, the ³He/⁴He values are（0.002–2.190）×10^-6, the R/R_a values are 0.01–1.52, and the contribution is estimated to be 0.09%–19.84%, suggesting a relatively small percentage. In contrast, the contribution of crust-derived helium is more than 80%. For crust-sourced helium, the in-situ 4He yield is only（4.10–4.25）×10^-4 cm³/g, while the external ⁴He flux is significantly high, being（5.84–9.06）×10^-2 cm³/g, indicating that crust-sourced helium is dominated by external input, which is speculated to be related to atmospheric recharge of formation fluids and deep rock-water interaction. Deep hydrothermal fluid in the diapir area significantly affects the geothermal field. The ratio of the initial mass volume of ³He to the corresponding enthalpy（W） is（0.006–0.018）×10^-11 cm³/J, and the thermal contribution from the deep mantle（XM） is between 7.63% and 36.18%, suggesting that the diapir thermal fluid plays a certain role in driving the migration of mantle-sourced ³He. The primary migration of helium in the study area is dominated by advection, and the secondary migration is controlled by hydrothermal degassing and gas-liquid separation. During the migration of helium from deep to shallow, the CO₂/³He value increases from 1.34×10⁹ to 486×10⁹, indicating the large-scale precipitation of CO₂ and apparent escape of ³He due to the effect of crust-mantle mixing and degassing. Under the influence of deep hydrothermal fluid, the migration and accumulation mechanisms of helium include: deep heat driven diffusion, advection release, vertical hydrothermal degassing; shallow lateral migration, accumulation in traps far from faults; partial pressure balance, complete cover sealing; and so on.更多还原