Nanya, Ruifang District, New Taipei City, Taiwani

Regional Level Types
Nanya	Outcrop
Ruifang District	District
New Taipei City	County
Taiwan	Disputed Territory

This area is part of the Pliocene Kueichulin Formation (6.5–4 Ma), which consists of thick interbedded sequences of sandstone, argillaceous sandstone, and shale. These sediments were deposited in wave- and tide-dominated shallow marine to deltaic environments. Based on lithological characteristics, the lower portion of the Kueichulin Formation is also referred to as the Tapu Formation. This unit is characterized by thick-bedded, dark yellowish sandstone and greyish, fine-grained argillaceous sandstone interbedded with shale layers. Marine fossils, including Ditrupa species, are commonly found in this interval. The top boundary of the Tapu Formation is notably enriched with ferric oxide concretions, from which the sample used in this study was obtained. The upper portion of the Kueichulin Formation is known as the Erchiu Formation. It is composed primarily of interbedded, thick, greenish-grey argillaceous sandstone and siltstone, along with shale. Raman spectroscopic analysis reveals that the degree of graphitization and diagenesis of kerogen varies spatially across the concretion: core (B) < rim (A) < matrix (M). The presence of the D3 band in the core and its absence in the rim and matrix suggest that the core kerogen has undergone significantly less alteration and retains more of its original organic structure. The dense and compact hematite mantle contributes to the preservation of the core by providing a barrier to external diagenetic and weathering influences.

Other Regions, Features and Areas containing this locality

References