法国比利牛斯造山带+岩石圈地幔中部分熔融和再富集作用过程的定量化模拟及定年（2024）

基于地球化学视角区分熔融耗竭与再富集产物，并限定次大陆岩石圈地幔（SCLM）内地幔-熔体相互作用的时限仍是亟待解决的关键问题。本研究通过alphaMELTS热力学模拟系统解析比利牛斯造山带Lherz地幔岩的成因演化：①部分熔融与再富集作用在元素响应上存在显著差异——再富集作用表现为升高的TiO₂/Al₂O₃比值及全岩/单斜辉石中更高的重稀土元素（HREE）丰度；②Lherz橄榄二辉岩主体为古元古代（~2.0 Ga）高程度部分熔融的残余体，少量具低熔体/岩石比的再富集特征；与橄榄纹层状岩密切共生的二辉橄榄岩为原始难熔型harzburgites与上升N-MORB型熔体相互作用的次生产物；而缺乏特殊空间关联的lherzolites则可能源于软流圈地幔经历中等程度绝热上涌后，在岩石圈基底经静态冷却形成。
通过创新性改良渗透模型结合Re-Os与Lu-Hf同位素体系分析，首次提出再富集事件发生于1.5–2.0 Ga期间。结合全球克拉通与非克拉通区SCLM成分数据库对比显示：①硅酸盐熔体主导的再富集作用可通过元素水平有效鉴别；②不同熔融机制对SCLM成分演化的贡献具有时空分异特征；③再富集过程通过改变地幔的地球化学特征（如Mg#降低、密度增大）与机械强度（如黏度变化），深刻影响了古老SCLM的稳定性与长寿期维持机制。该研究为理解大陆岩石圈多阶段演化提供了新的理论框架。该论文数据主要包含法国比利牛斯造山带橄榄岩全岩强亲铁元素及Re-Os同位素数据，来源于中国地质大学（北京）同位素实验室检测，加工方法为将选好的样品经过化学纯化流程处理后用于负热电离质谱仪N-TIMS和高分辨电感耦合等离子体质谱仪HR-ICP-MS的实验数据采集，通过样品-标液间插法以及内标法进行质量歧视矫正。误差以2σ给出。法国比利牛斯造山带橄榄岩单矿物Lu-Hf同位素数据，来源于中国地质大学（北京）同位素实验室检测，加工方法为将粗粉碎的Cpx和Opx经过化学纯化流程处理用于MC-ICP-MS的实验数据采集，标样BHVO-2的测试结果与参考值在误差范围内保持一致。法国比利牛斯造山带橄榄岩全岩主量元素数据，来源于加拿大劳伦森大学检测，处理方法为将研磨好的岩石粉末经过前处理后用于波长色散X-ray 荧光光谱仪的实验数据采集，使用铂金坩埚将样品粉末制成玻璃片。测试结果中，Si-Ti-Fe-Ca-Ba-K-P的分析精度优于±1%，Al-Cr-Mn-Mg-Na的分析精度优于±2%（2σ）。法国比利牛斯造山带橄榄岩全岩微量元素数据，来源于加拿大劳伦森大学检测，加工方法为将研磨好的岩石粉末经过前处理后用于PerkinElmer Sciex ELAN 9000 四级杆ICP-MS的实验数据采集，使用铂金坩埚将样品粉末制成玻璃片。分析精度一般优于10%，个别元素(如Er、Hf、Lu、Pr、Tb、U和Y)的分析精度10 ~ 15%，大多数元素的分析精度优于±10%，中高浓度元素的分析精度优于±2 ~ 8%。法国比利牛斯造山带橄榄岩单矿物主量元素数据，来源于中国科学技术大学检测，加工方法为将样品探针片经过前处理后用于电子探针JXA-8530F Plus和LA-ICP-MS实验数据采集，测试过程中采用的加速电压为15 kV，电流为10 nA，束斑直径为3 μm。峰位的测试时间为10 s，背景的测试时间为峰位的一半。标样是来自SPI和P&H公司的天然或合成矿物。使用ZAF法对数据进行基体校正。对于通常大于1.0 wt.%的元素，分析精度优于±10%（2σ）。法国比利牛斯造山带橄榄岩单矿物微量元素数据，来源于加拿大阿尔伯塔大学检测，加工方法为将岩石薄片经过前处理后用于原位-激光单接收等离子体质谱仪LA-ICP-MS的实验数据采集，激光剥蚀系统为RESOnetics Resolution LR50，ICP-MS为Thermo Scientific Element 2XR。分析过程采用130-285 μm 激光剥蚀束斑，20Hz脉冲频率和4J/cm2激光能量密度。每6个测试点测定一组标样，来进行灵敏度漂移校正。微量元素用iolite 4.0软件进行处理和计算，过程中，NIST612玻璃的Si作为内标进行矫正，NIST612,NIST614,BIR1G, BCR2G, BHVO2G标样作为二次标样监测准确性。

Distinguishing between melt-depleted and refertilized products from a geochemical perspective and constraining the time limit of mantle-melt interactions within the Subcontinental Lithospheric Mantle (SCLM) remain critical unresolved issues. This study systematically deciphered the genetic evolution of Lherz peridotites from the Pyrenean orogen via alphaMELTS thermodynamic simulations: ① Partial melting and refertilization exhibit distinct elemental geochemical responses—refertilization is characterized by elevated TiO₂/Al₂O₃ ratios and higher heavy rare earth element (HREE) abundances in whole rocks and clinopyroxenes; ② The majority of Lherz olivine websterites are residues formed by high-degree partial melting during the Paleoproterozoic (~2.0 Ga), with a small portion showing refertilized features with low melt/rock ratios; The lherzolites closely associated with olivine layered rocks are secondary products formed by the interaction between primitive refractory harzburgites and ascending N-MORB-like melts; while lherzolites without special spatial associations likely formed via static cooling at the lithospheric basement after moderate adiabatic upwelling of the asthenospheric mantle.

By combining an innovatively modified percolation model with Re-Os and Lu-Hf isotope system analyses, this study firstly proposed that refertilization events occurred between 1.5–2.0 Ga. A comparison with global SCLM compositional databases from cratonic and non-cratonic regions reveals: ① Silicate melt-dominated refertilization can be effectively identified via elemental geochemical proxies; ② Different melting mechanisms exhibit spatiotemporally heterogeneous contributions to the compositional evolution of SCLM; ③ Refertilization profoundly influences the stability and long-term survival mechanisms of ancient SCLM by altering the geochemical characteristics (e.g., decreased Mg#, increased density) and mechanical strength (e.g., viscosity changes) of the mantle. This study provides a new theoretical framework for understanding the multi-stage evolution of the continental lithosphere.

The data presented in this paper mainly include whole-rock strongly siderophile element and Re-Os isotope data of peridotites from the Pyrenean orogen, France, which were measured at the Isotope Laboratory of China University of Geosciences (Beijing). The processing workflow involves chemically purifying selected samples, followed by data acquisition using Negative Thermal Ionization Mass Spectrometry (N-TIMS) and High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Mass discrimination was corrected via sample-standard bracketing and internal standardization, with errors reported at 2σ.

Lu-Hf isotope data of mineral separates (clinopyroxene [Cpx] and orthopyroxene [Opx]) from the Pyrenean peridotites were also measured at the Isotope Laboratory of China University of Geosciences (Beijing). Coarse-pulverized Cpx and Opx were chemically purified prior to analysis via Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The test results of standard BHVO-2 are consistent with reference values within error ranges.

Whole-rock major element data of the Pyrenean peridotites were measured at Laurentian University, Canada. Ground rock powders were pre-treated and analyzed using a wavelength-dispersive X-ray fluorescence (WD-XRF) spectrometer, with sample powders made into glass fusion discs using platinum crucibles. The analytical precisions for Si, Ti, Fe, Ca, Ba, K, and P are better than ±1%, while those for Al, Cr, Mn, Mg, Na are better than ±2% (2σ).

Whole-rock trace element data of the Pyrenean peridotites were measured at Laurentian University, Canada. Ground rock powders were pre-treated and analyzed using a PerkinElmer Sciex ELAN 9000 quadrupole ICP-MS, with sample powders made into glass fusion discs using platinum crucibles. The analytical precisions are generally better than ±10%, with some elements (e.g., Er, Hf, Lu, Pr, Tb, U, and Y) showing precisions of 10–15%, and most elements with precisions better than ±10%, while moderately and highly concentrated elements have precisions better than ±2–8%.

Major element data of mineral separates from the Pyrenean peridotites were measured at the University of Science and Technology of China. Sample probe mounts were pre-treated and analyzed using an electron probe microanalyzer (EPMA) JXA-8530F Plus and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The test parameters include an accelerating voltage of 15 kV, beam current of 10 nA, and beam spot diameter of 3 μm. The peak counting time is 10 s, and the background counting time is half of the peak time. Reference materials are natural or synthetic minerals from SPI and P&H companies. Data were corrected via the ZAF method. For elements with concentrations greater than 1.0 wt.%, the analytical precisions are better than ±10% (2σ).

Trace element data of mineral separates from the Pyrenean peridotites were measured at the University of Alberta, Canada. Thin sections of rocks were pre-treated and analyzed via in-situ laser ablation single-collector ICP-MS, using a RESOnetics Resolution LR50 laser ablation system and a Thermo Scientific Element 2XR ICP-MS. The analytical parameters include a laser ablation spot size of 130–285 μm, pulse frequency of 20 Hz, and laser fluence of 4 J/cm². One set of standards was measured every 6 test points for sensitivity drift correction. Trace element data were processed and calculated using iolite 4.0 software, with Si from NIST612 glass used as the internal standard for correction, and standards NIST612, NIST614, BIR1G, BCR2G, and BHVO2G used as secondary standards to monitor analytical accuracy.