|
Palm Park Formation
The Palm Park Formation is a geologic formation in southern New Mexico. It preserves fossils dating back to the Eocene epoch. Description The formation consists of reddish clastic sediments, including some beds of boulder conglomerate with individual boulders up to in diameter. The red color is attributed to a source in the Abo Formation. The upper beds contains considerable latite to andesite breccia interbedded with tuffaceous claystone and siltstone. The Palm Park Formation rests gradationally on the Love Ranch Formation, is unconformably overlain by the Bell Top Formation, Rincon Valley Formation, or Santa Fe Group, and has a thickness of about . The original age estimate, based on radiometric ages of intrusions and interbedded flows, ranged from 42 to 51 million years. More recent high-precision U-Pb dating gives an age of 45.0±0.7 Ma for an ash fall tuff in the lower part of the formation in the Robledo Mountains and an age of 39.6±0.5 Ma for an ash fall tuff in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
