You are Here, Now: a Geology Report
Breaking news! Continents Clash!
But slowly. The Pacific Ocean once beached near here where Ashland later grew. The whole continent we now know as North America slowly slid westward over the hot magma underlying it. The remnants of southeastern Oregon mountains started as volcanos blasting out of the same huge hot spot that now underlays Yellowstone. The hot spot didn’t move; the continent pushed westward above it. Similarly, Hawaii is pushing northwest over a hot spot now generating lava on the Big Island and in the ocean south of it.
The local beach moved westward, not just because of the moving continent, but more so from a series of volcanos in northeast Oregon and the Cascades (very recent ones in the last million years, like Mt. Shasta, Mt. Hood, and Mt. St. Helens, and the older 40 million year old so-called “Modern” Cascades). Layers of ash and basalt rock make the land we now call home. In geologic time, the tops of the Table Rocks near Medford were once the valley floor, which has since eroded beneath them, carrying their stuff towards the ocean.
The recent and modern Cascades were fueled by the Juan de Fuca and Pacific plates ramming in eastward from an erupting Pacific ocean fissure, diving under the slower westward-moving North American continent. All that friction heat pops up as volcanos as the land gets wrinkled and heaved.
But that’s not all about this geologically unique area. The Klamath Mountains, familiar to us now (starting at about I-5 and rising up southward and westward into southwest Oregon and the northern quarter of California) were not a part of North America. Once separate islands, this ancient island ark became part of North America. They were jammed up into it, spun almost a half-turn by a plate zooming north, now under B.C. Canada. Spun and jammed, it is far older than the bulk of the rest of Oregon.
This is old news. Given enough time, the earth looked various ways. North and South America were once contiguous with Europe and Africa. As the mid-Atlantic fissure kept erupting, it widened the Atlantic. The isthmus at Panama rose as it connected North and South America, changing the wind currents and the weather in Africa. The French Broad River, now in North Carolina flowing northward to the old French Territories and the Ohio River, was once adjacent to Ethopia when all was collected as Pangea. It is considered the second oldest river in the world.
Here’s a short animation showing the movement of plates and continents from Pangea to present: https://www.youtube.com/watch?v=WaUk94AdXPA. Pangea was the more recent supercontinent, forming 270 ma and breaking up about 200 ma. There were earlier ones as well.
Nor has it all stopped. The Sea of Cortez between Baja and mainland Mexico continues to separate the land all the way up through Nevada, though this may be stopping. Baja itself could migrate northward, no matter Trump’s wall.
Ashland itself rides on a huge pluton, a superheated granitic upgrowth from deep in the earth. Possibly part of the same deep force that grew the Blue Mountains and the erupting Klamaths, huge granitic batholiths well up. Ashland’s may be oldest – about 160 million years old. The Oregon Caves rest on the Greyback batholith of similar age. Jacksonville (154 ma)(ma= million annum, or years), Gold Hill (150 ma), and Grants Pass (139 ma). All this and the Klamaths is part of a 3 to 5 million year episode of intense volcanic activity called the Siskiyou orogeny. Gold cools slower than quartz, deep in the cracks at the boundaries of plates faulting (crashing into each other). Up in the Blue Mountains, the Cornucopia Mine has gold mine shafts up to 3,000 feet deep, running for 36 miles of tunnels.
The earliest large animals were mostly under-sea creatures like ichthyosaurs (fish lizards), and only a few dinosaurs have been found, perhaps the remnants of their having earlier lived southward, then their bones faulted north. The huge Idaho mountains may have prevented tyrannosaurs and flying pterosaurs from entry, except at the Blue Mountains in northeast Oregon. But later life emerged in abundance in a lush temperate forest and eventual grassy savannahs. Amidst palms and magnolias, figs and sycamores, early horses, rhinos, and small elephant-like creatures abounded.
I like knowing about the scales of time and space we humans have only recently come to understand. Things are so vast and old; it puts our petty concerns in perspective. Earth’s thin and fragile ecosphere is our precious island home in the midst of the heavens we’ve long loved as stars (and their planets) places we know exist but will not likely soon visit. Ellen Morris Bishop, author of In Search of Ancient Oregon, comments after discussing the recent Cascades (only 40 ma):
“Humans seldom think in this timescale, especially when we consider the future. (In fact, the English language has a paucity of words that even express the concept of future.) It is…tantalizing to grasp the idea that the planet and its landscapes, animals, and plants not only have a history that spans hundreds of million[s] of years, but a future that should last at least that long.” (Pg.50-51)
Indeed. We can barely acknowledge seven generations into our future, much less multi-millions of years. Here’s a peek at our future in the next 100 ma: https://www.youtube.com/watch?v=7BxnIkqK1J4
As we reap profits that last mere moments while leaving trouble that will last millennia, I wonder how bad or good our future could be. We need to move from profits to prophets. I saw a man on Ashland’s Plaza (where Shasta Tribe natives used to hang out long before there was a town) wearing a prophetic sign:
“The middle is near!”
My appreciation goes to Dr. Karen Grove for her Olli class and to Dr. Ellen Bishop’s book for helping generate this report. Any mistakes in interpretation are mine; I barely know about this extensive knowledge. I just had to share my enthusiasm for this part of the larger, longer reality that supports, generates and allows us to be at all. To me, this is religion: knowing the truth of reality and living well with it.