Purpose

The cost-efficient methods of analysis, such as rapid short-wave infrared (SWIR) spectral analysis, have been applied for the efficient exploration of critical raw materials (CRM), including mineral components and rare earth elements (REE) from the deep-ocean sediments.

Methods

Gravity cored sediment samples were collected during an oceanographic mission to the Trans-Atlantic Geotraverse (TAG) hydrothermal field of the Mid-Atlantic Ridge (MAR, 26° N). SWIR reflectance spectra (dependent variable) of samples were mathematically tested against referent geochemical data (independent variable), obtained by conventional analysis (ICP/OES, ICP/MS), after applied full cross-validation multivariate partial least square regression (CVPLSR). Value of parameter-residual predictive deviation (RPD) was used for evaluation of CVPLSR modeling: RPD > 2.5 (satisfactory calibration model for the screening purposes) and RPD > 5.0 (model adequate for the quality control of the studied elements).

Results

The CVPLSR modeling provided significant results for the determination of several mineral components: major elements (Fe and Si) had the values of RPD equal to 3.65 and 2.84, respectively, which indicated a viable potential for their routine analysis, whereas RPD for Ca was equal to 5.51, thus assuring its quality control by SWIR analysis, in sediment samples of the studied location. Among the REE, Ce (RPD = 2.55) and Er (RPD = 2.59) yielded the most satisfactory results.

Conclusions

The findings highlight the benefit of rapidly obtained empirical SWIR-reflectance data, which can be used for near-real-time exploration of geochemical deposits hosted in deep-ocean sediments.

中文翻译：

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TAG热液场（MAR，26°N）的深海沉积物分析：短波红外反射光谱在近海地球化学勘探中的应用

目的

具有成本效益的分析方法，例如快速短波红外（SWIR）光谱分析，已被用于有效勘探深部矿物的关键原材料（CRM），包括矿物成分和稀土元素（REE）。海洋沉积物。

方法

在对大西洋中脊（MAR，26°N）的大西洋跨地热（TAG）热液场进行海洋学任务期间，收集了重力岩心沉积物样品。在应用完全交叉验证多元偏最小二乘回归（CVPLSR）之后，通过常规分析（ICP / OES，ICP / MS）对参考地球化学数据（独立变量）进行了数学测试，对样品的SWIR反射光谱（因变量）进行了测试。参数残差预测偏差（RPD）的值用于CVPLSR建模的评估：RPD> 2.5（用于筛选目的的令人满意的校准模型）和RPD> 5.0（足以用于所研究元素的质量控制的模型）。

结果

CVPLSR模型为确定几种矿物成分提供了重要的结果：主要元素（铁和硅）的RPD值分别等于3.65和2.84，这表明它们的常规分析具有可行性，而Ca的RPD等于到5.51，从而通过SWIR分析确保了对所研究位置的沉积物样品的质量控制。在REE中，Ce（RPD = 2.55）和Er（RPD = 2.59）产生了最令人满意的结果。

结论

这些发现强调了快速获得经验SWIR反射数据的好处，该数据可用于深海沉积物中的地球化学沉积物的近实时勘探。