New Page--Plant Fossils At The La Porte Hydraulic Gold Mine, California
From Inyo@21:1/5 to All on Tue Sep 22 12:13:00 2020
Not too long ago, I uploaded to http://inyo3.coffeecup.com/laporte/laportefossils.html my latest paleontology-related page--Plant Fossils At The La Porte Hydraulic Gold Mine, California . Contains a detailed text, in addition to on-site photographs and
images of representative fossil specimens with explanatory captions.
It's a virtual visit to a famous leaf-bearing locality in the upper Eocene La Porte Tuff (dated radiometrically at 34.2 million years old), exposed at a long-abandoned hydraulic gold mining pit in the vicinity of La Port, Plumas County, northern Sierra
Nevada, California. Some 43 species of Cenozoic plants have been secured from the La Porte Tuff, a paleobotanical flora that consists of often exquisitely preserved leaves from dicotyledons, mainly, whose closest modern-day counterparts live primarily in
subtropical areas of Mexico, Central America, South America, southern China, and the Philippines--a dramatic difference in botanic components from today's dominant montane Sierra Nevada association of gymnospermous conifers.
A rather interesting geological sidelight here is that nobody can actually correlate the upper Eocene La Porte Tuff with any known late Eocene to early Oligocene volcanic tuff or ignimbrite deposit presently exposed in either neighboring Nevada or the
Sierra Nevada; that is to say, it just doesn't fit mineralogically with any other known volcanic event. Some investigators speculate that it could be related to a documented late Eocene extrusive impulse in the Cascade physiographic region, but it's far