The sedimentary rocks of the Cabullona Group are well exposed in the Cabullona Basin of northeastern Sonora,Mexico,which represent syntectonic sedimentation associated with Laramide-style deformation during the Campan...The sedimentary rocks of the Cabullona Group are well exposed in the Cabullona Basin of northeastern Sonora,Mexico,which represent syntectonic sedimentation associated with Laramide-style deformation during the Campanian-early Maastrichtian.The sandstones of the Lomas Coloradas Formation deposited at the upper part of the Cabullona Group.Petrography and geochemical(major,trace,and rare earth elements)studies were carried out on the sandstones to interpret the palaeoweathering,provenance,and tectonic setting of the Lomas Coloradas Formation sandstones.Most of the sandstone modal analysis data plotted in the QFL and Qm FLt ternary diagrams fall into the fields of dissected arcs and recycled orogens,respectively.Geochemically the sandstones are classified as litharenites while few samples plot into the arkosic field.The chondrite-normalized REE diagrams for sandstones have LREE-enriched,relatively flat HREE patterns with negative Eu anomalies.CIA values and the A-CN-K diagram indicate a low intensity of chemical weathering in the source area.The tectonic setting diagram suggests both arc and rift settings for the studied sandstones.The bivariate and ternary diagrams and elemental ratios suggest a felsic source for the Lomas Coloradas Formation.The average REE patterns of the studied sandstones are comparable with REE patterns of the granite from the Caborca block,the rhyolite and granite of the Tarahumara Formation,and the Mesozoic felsic volcanic rocks.The modeled mixture of 40%Proterozoic granite,30%Triassic arc,10%Jurassic arc,and 20%Laramide arc represents the probable source rocks for the Lomas Coloradas Formation.展开更多
基金financially supported by the Programa de Apoyo a Proyectos de Investigaci on e Innovaci on Tecnol ogica (PAPIIT)Projects (Nos.IN112214 and IN109422)by Direcci on General de Asuntos del Personal Acad emico,Universidad Nacional Aut onoma de MexicoDirecci on General de Asuntos del Personal Academico (DGAPA),Universidad Nacional Autonoma de Mexico (UNAM)for financial support through PAPIIT Projects (Nos.IN112214 and IN109422)。
文摘The sedimentary rocks of the Cabullona Group are well exposed in the Cabullona Basin of northeastern Sonora,Mexico,which represent syntectonic sedimentation associated with Laramide-style deformation during the Campanian-early Maastrichtian.The sandstones of the Lomas Coloradas Formation deposited at the upper part of the Cabullona Group.Petrography and geochemical(major,trace,and rare earth elements)studies were carried out on the sandstones to interpret the palaeoweathering,provenance,and tectonic setting of the Lomas Coloradas Formation sandstones.Most of the sandstone modal analysis data plotted in the QFL and Qm FLt ternary diagrams fall into the fields of dissected arcs and recycled orogens,respectively.Geochemically the sandstones are classified as litharenites while few samples plot into the arkosic field.The chondrite-normalized REE diagrams for sandstones have LREE-enriched,relatively flat HREE patterns with negative Eu anomalies.CIA values and the A-CN-K diagram indicate a low intensity of chemical weathering in the source area.The tectonic setting diagram suggests both arc and rift settings for the studied sandstones.The bivariate and ternary diagrams and elemental ratios suggest a felsic source for the Lomas Coloradas Formation.The average REE patterns of the studied sandstones are comparable with REE patterns of the granite from the Caborca block,the rhyolite and granite of the Tarahumara Formation,and the Mesozoic felsic volcanic rocks.The modeled mixture of 40%Proterozoic granite,30%Triassic arc,10%Jurassic arc,and 20%Laramide arc represents the probable source rocks for the Lomas Coloradas Formation.
