While this separation of South America and inland waterways open to the sea (discussed in the last post) was basically unknown to most of history, and the geologic time scale placed it far into the past and out of the public conscience, it was studied by a few. Even Charles Darwin as late as 1835 suspected that the giant mountains, huge volcanoes and great earthquakes that occur along the Pacific coast of South America were related in a much more recent time frame, and others have been exploring this area, which has had a profound effect on modern thinking.
The Glomar Challenger, the first research vessel built to drill core samples from the deep ocean seabed, proved on Leg 3 during its 1968-1969 mission what was first suspected as early as 1596 by Abraham Ortelius and more developed in 1912 by Alfred Wegener, that plate tectonics existed. During Leg 68 in 1979, the Challenger found that the Isthmus of Panama at one time was submerged, verifying that the Arato Sea had once flowed between the Atlantic and Pacific. Then, very recently in geologic time, the South American plate subsequently moved northward impacting this peninsular extension of Central America, and formed the Isthmus of Panama (see our post of September 1, 2012 “The Odyssey of the Glomar Challenger Drillship and the Panama Isthmus”).
As a side note for those who might be interested, the Challenger also discovered that while geologists claim the Earth is 4.55 billion years old, that the ocean floor was less than 200 million years old.
In any event, while Darwin was the first to recognize and write about this in the modern era, by the 1960s, geologists realized that these phenomena were all consequences of the fact that the oceanic Nazca plate was sliding under the South American plate.
While scientists studying plate tectonics have been able to observe changes only as they accumulated in the geologic record over millions of years, due to the continent-sized plates moving only a few inches each year, modern GPS technology has been refined to get sub-centimeter accuracy. The results now show that under normal circumstances, about three inches of motion per year occurs between the Nazca and South American plates, and is divided three ways.
According to NASA and the National Science Foundation, the rise of the Andes is about 1.4 inches per year of the Nazca plate slides smoothly under South America, giving rise to volcanoes. Another 1.3 inches per year is locked up at the plate boundary, squeezing South America, and is released every hundred years or so in great earthquakes. About 0.3 inches of motion per year crumples South America, building the Andes.
The interesting part of this is the new findings by Carmala Garzione, et all, (see last post), show a broad range of geologic indicators, including the history of folding and faulting, erosion, volcanic eruptions, and sediment accumulation, which all suggests a hotly debated tectonic process called delamination is likely at work in the Andes. Although delamination has been proposed for decades, Garzione says it has been controversial because mechanical models of mountain-building have a hard time reproducing it, and, until the new findings, there has been a lack of reliable measurements.
In geophysics, delamination refers to the loss and sinking (foundering) of the portion of the lowermost lithosphere from the tectonic plate to which it was attached. Thus, when oceanic and continental plates come together, geologists believe the continental crust buckles. On the surface, the buckling manifests itself as a rising mountain range, but beneath the crust, Garione claims, the buckling creates a heavy, high-density "root" that holds the crust down like an anchor. Conventional tectonic theory says that convection of the fluid mantle deep in the Earth slowly erodes this heavy root like a stream wearing down a rock, allowing mountains to gradually rise as the crust shortens and thickens.
Delamination has often been cited to explain regional uplift whether by “peeling” of the lithospheric mantle and in some cases a part of the lower crust, or by viscous dripping (convective removal). Various geodynamic contexts such as high plateau near a plate boundary such as Tibet, Anatolia, or the Andes are places where delamination is believed to occur. In the image below of an oblique lateral view, an asthenospheric flow introducing the lower crust decouples the lithospheric mantle, which delaminates and sinks into the asthenosphere.
According to Garzione, the delamination theory suggests that instead of eroding slowly away over a long period of time, the root heats up and oozes downward like a drop of molasses until it abruptly breaks free and sinks into the hot fluid mantle. The mountains above, suddenly free of the weight of the blob, would rush, or “pop” upward in geologic terms, and form mountains much faster than was ever believed.
Obviously, no human has seen the forming or creation of the Earth, (nor other than those involved at the time) seen Noah’s Flood, the division of the Earth in Peleg’s time, or the changes at the time of the Crucifixion. Consequently, these events have no meaning to non-believers. They obviously are not accepted by those who geologically measure earthly events. Thus, geologists and others know about minute changes, but know nothing of the Lord’s power or understand how He has been involved in the altering of the Earth since its organization (creation).
So we have to look outside the geologic world and into that special world of the believer in God the Father and His son, Jesus Christ. In that world, we can talk about that great Architect who created the earth in the first place. During the crucifiion, in the space of three hours, he pushed, squeezed and realigned the tectonic plates by the “power of his word,” and by that power delaminated the mountain core of the proto-Andean uplift until mountains, “whose height is great” shot into the sky all along the Andean uplift. The pressure caused earthquakes all along the Pacific coast of South America as God sent the Nazca plate ramming deeper under the South American plate that “shook the whole earth as if it was about to divide asunder” (3 Nephi 8:6), “And there was a great and terrible destruction in the land southward…and there was a more great and terrible destruction in the land northward; for behold, the whole face of the land was changed, because of the…exceedingly great quaking of the whole earth” (3 Nephi 11-12).
As these tall mountains came up, the seas to the east of the Land of Promise were pushed back—the Pebesian Sea into the North and East portal seaways (and out into the Atlantic), around both sides of the emerged Guayanan Shield, the Marine Ingression Amazon Sea was pushed eastward between the emerged Guayanhan and Brazilian Shields, and the Paranense Sea was pushed southeast through the South portal seaway to the east of Patagonia and west of the southern Brazilian Shield. At the same time, the rise of the Andes brought up the adjoining lands to the east, filling in the Amazon Basin and pushing out through what became the Amazon River the previous marine ingression, forming the Amazon Delta, and over time the subaqueous and subaserial accumulation of river-derived sediments formed at the mouth of the river that we see today.
At this time, with the Andes mountains we now see at their considerable height, still isolating the western coastal shelf of South America from the eastward lands, the Nephite Sea East ceased to exist.
(See the next post, “Changing Land of Promise—The Effect of Rising Mountains - Part V and the Disappearing Sea East,” for more information on the changes wrought by the events described in 3 Nephi, and their effect on the Land of Promise before and after 34 A.D. and how the Lord intervened to change this landscape in three hours)
With the Central American Seaway opened, the ocean currents would likely have been significantly different.
ReplyDeleteDo you know of any theories on how the currents would be different?
The Gulf's Streams northern extension has an enormous, beneficial, effect on the European landmass. If that were significantly altered, that should leave significant (or, at least, noticeable) changes that in the climate record that could give further confirmation of massive change in the earth at that time.