as my recent field trips to coastal and mountainous locations on Southern Vancouver Island have left me with some serious doubts...
What are your thoughts about the way they reconstruct past solar activity to create estimations of ice-ages?
Whereas some of the glacial gravel and boulders could be explained by electrical explanations, it looks certain that there was ice over much of North America not long ago, and also that the ice advanced and retreated at least a few times.
After this the Earth went into an elliptical orbit around the Sun which caused alternating very cold and very hot conditions.
Could you lay out a couple of specific instances, and your alternatives ?
About 100 million years ago, Wrangellia collided with the North American continent. Slow but tremendous forces caused some regions to fold and buckle into mountain ridges and others to crumble and erode.
55 to 42 million years ago, two smaller pieces of crust called the Pacific Rim and Crescent terranes collided with and joined onto Vancouver Island. The Crescent terrane is composed of marine volcanic rock and forms the land of Sooke, Metchosin and Colwood. The region that Victoria is built upon is granite and gneiss (metamorphic rock) that is thought to have formed from magma deep within the layers of rock. It was exposed during the uplift and erosion associated with the collisions of the Pacific Rim and Crescent terranes.
The Oceans and Islands phase began in Devonian-Mississippian time with the first widespread arc volcanism and plutonism along the continent margin: these rocks are recognized from southern California to Alaska. West of the North American miogeocline, a large portion of California, Oregon, Washington, British Columbia, and most of Alaska are made up of rocks of intra-oceanic island arc to oceanic affinity that occur in relatively coherent packages separated from each other by faults. These assemblages, famously termed a collage of “suspect terranes” by Peter Coney and Jim Monger, had uncertain relationships to the North American continent during at least part of their history. Most of them have now been shown either to contain faunas of eastern Pacific affinity (an excellent example can be viewed at the Lafarge limestone quarry near Kamloops, B.C.), or to exhibit sedimentological, geochemical and/or historical aspects that link them, however distally, to the continent. Some, however, are more convincingly exotic imports: the Cache Creek Terrane of central British Columbia with its Tethyan, Japanese-Chinese, late Permian fusulinid fauna; Wrangellia and Alexander, a linear belt on the coasts of B.C. and southeastern Alaska, with its late Paleozoic cold-water, Baltic-affinity fauna; and fragments of continental crust in Alaska with Precambrian ages that are unknown in North America.
The ice formed two lobes at the south end of Vancouver Island. One flowed south toward Seattle and terminated near Tacoma. The other flowed westward and northwestward through Juan de Fuca Strait and ended in a shelf some distance to the west of the Island.
Evidence of the direction of flow of these ice sheets can be seen in rocks around Victoria. Generally, striations in the rock are aligned with the direction of this flow. Although the overall flow was north to south, local variations occur where the ice moved over obstructions and where it turned eastward close to Juan de Fuca Strait. Some rocks are gradually and smoothly sloped on one side, and rough on the other side, somewhat like a rounded breaking wave. These are called roches moutonées, and the smoother side is the one the ice contacted first.
GaryN wrote:The proof of an ice age is based on the interpretation of the evidence supposedly left behind. Polished bedrock, sand and gravel piles, glacial valleys, out of place boulders that must have been pushed hundreds of miles from their origins. But if these features could be explained by electrical and plasma forces, might it be that the ice ages never existed?
I know lot of information from this side, so sad because my english is what is.
seasmith wrote:Hello finno,
Another thought: a Skandinavian land mass rebound, as ice cover recedes, could cause more than a few minor earthquakes ?)
About 100 million years ago,...(from http://www.crd.bc.ca/watersheds/protect ... toryVI.htm )
Something smoothed them into boulders, because granite breaks off in ragged chunks....
"...unknown unknowns", as opposed to known unknowns
Some significant additional factors supporting and episode of continental glaciation are:
1. various indications and scales of scouring, including parallel striations on boulders, which Gary may have seen on south Vancouver Island, also along the coastline of Washington and some of the San Juan islands
2. glacial deposits, including till and ancient moraines, etc.
3. fast frozen mammoths with undigested identifiable tropical plants in their stomachs
4. current continental glaciation with a [continuous?] historical connection to the recent "Pleistocene" events.
(pdf)Phase change and earthquakes.
finno wrote:...so sad because my english is what is.
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