Mineralogy Recognition from In-Situ Elemental Concentration Log Data Using Factor Analysis Ahmed Amara Konaté, Heping Pan, Nasir Khan, Oumar Keita, Mamady Cissé, Mory Kourouma, and Daouda Keita Abstract Understanding log response in crystalline rocks is one of the major challenges encountered by geoscientists in general, and well-log analysts in particular. Owing to the persistence of metamorphism process, log interpretation in crystalline rocks appears to be a challenging task. In this context, the present study is focused on reporting the results drawn from the interpretation of elemental concentration log data. For an effective elemental con- centration interpretation to take place, an appeal is made to the factor analysis method. Hence, constructing a model whereby elemental concentrations could be asso- ciated with mineral abundances is investigated and discussed. The reached results appear to reveal that the elemental concentration logs turn out to provide enough information useful for an accurate lithological description of crystalline rocks to take place, especially with regard to UHPM rocks. Keywords Crystalline rocks Á Log interpretation Á Factor analysis Á Geochemical log 1 Introduction The well logs relating applications are noticeably advanced in the petroleum industry. Consequently, log signatures in sedimentary rocks turn out to be widely known. Yet, this is not always the case for crystalline rocks [2]. Compared with sedimentary rocks, crystalline rocks are more diverse, bearing rather complex compositions, textures, and struc- tures, ensuing in various challenges in their lithological identification [3]. Noteworthy, also, is that no systematically formulated interpretation method, dealing with the crystalline-rock cases, has so far been made available [4] in geophysics. As a result, understanding log response in crystalline rocks remains a major challenge the geoscientists face, particularly the well-log analysts. The CCSD project, subject of the present study, stands as one of the major geoscientific projects ever executed in China. The project has received financial and technical support from the part of the International Continental Dril- ling Program. The CCSD-Main Hole (CCSD-MH) is located too close to the Maobei Donghai County, at the Sulu Ultrahigh pressure metamorphic (UHPM) belt of Eastern China. Despite the existing research works, the CCSD-MH geochemical log database has not yet been thoroughly and fully exploited. Hence, it offers a unique opportunity to investigate the elemental concentration log responses asso- ciated with the Sulu UHPM belt. In this respect, the study intent lies in analyzing the CCSD-MH related elemental concentration log responses. To this end, a factor analysis approach is applied to construct a model whereby elemental concentration logs could be closely linked to the mineral abundances, while discussing the lithological-identification explanatory potentials and capacities. This study will contribute to the understanding of the log responses in regard of the CCSD-MH, as lying in the UHPM belt of Eastern China. 2 Data and Methodology The obtained in situ geochemical logs were: Aluminum (Al) [wt%], Calcium (Ca) [wt%], Iron (Fe) [wt%], Gadolinium (Gd) [ppm], hydrogen (H) [wt%], silicon (Si) [wt%], Sulfur (S) [wt%], Titanium (Ti) [wt%], Potas- sium (K) [%], Thorium (Th) [ppm], and Uranium (U) [ppm]. A. A. Konaté (&) Á O. Keita Á M. Cissé Á M. Kourouma Á D. Keita Institut Supérieur des Mines et Géologie de Boké, BP: 84, Boké, Guinea e-mail: konateahmed@hotmail.com H. Pan Á N. Khan Institute of Geophysics and Geomatics, China University of Geosciences (Wuhan), Wuhan, 430074, China © Springer Nature Switzerland AG 2019 D. M. Doronzo et al. (eds.), Petrogenesis and Exploration of the Earth’s Interior, Advances in Science, Technology & Innovation, https://doi.org/10.1007/978-3-030-01575-6_41 171