SEDIMENTOLOGY AND PROVENANCE OF SAN FELIPE FORMATION (UPPER CONIACIAN), SIERRA MADRE ORIENTAL, NORTHEAST MEXICO

The San Felipe Formation (Late Coniacian−Early Turonian) consits of a ritmic intebedding of black shale, fine to medium-grain sandstones and lapilli-ash tuff with benthonic foraminifera wackestones, as well as benthonic and planktonic foraminiferal wackestones. The studied formation shows two main facies that represent a one-facies association, interpreted as open-platform or siliciclastic ramp, that varies from proximal to distal, as proved by the documented ichnofacies (Cruziana and Zoophycus).

The modal analysis from Sandy beds of the San Felipe Formation, allows to propose three main petrofacies: 1) volcaniclatic petrofacies (Q₅₂F₂₅L₂₃), that reflect a continental or oceanic arc provenance; 2) quartz-feldespathic petrofacies (Q₅₈F₂₈L₂₂), and 3) sedimentoclastics petrofacies (Q₅₄F₁₆L₃₀) that show evidence of recycled collisional-orogens provenance, with high afinity of continental or oceanic arcs (~Qp₁₀Lv₈₇Ls₃).

Petrologic parameters suggest that the source-area composition for the three petrofacies was maily volcanic, possibly basaltic - riolythic with influnce of pyroclastic material. However, the metamorphic lithic fragments such as: metapellic₂, metapellic₃, metafelsitic/psamitic₃, and metafelsitic/psamitic₃, suggest low- to medium-grade metamorphic rocks, being the quartz-feldespathic petrofacies richer in the later. The possible volcanic source-lands are: i) Cordilleran Nazas Arc (190-145 Ma), Guerrero Terrane (180-150 Ma), meanwille the Novillo Complex, the Arramberri Schist’s, and the Coahuila-Texas Craton, can be the principal source rocks for metamorphic detritus.