THE BELOW TRIP TO TOROWEEP VALLEY AND OVERLOOK- AT THE GRAND CANYON (NORTH) IS DESCRIBED FOR HIKERS, IN THE 2ND BLOG- SCROLL DOWN TO THE INTRODUCTION.
NOTICE THE CIRCULAR PATTERN OF EXTRUSIONS AND VENT LOCATIONS ABOVE, LOOKING AT A LARGE-SCALE MAP (BELOW THAT, THE MAP TURNED 90 DEGREES IN ORDER TO EXPAND IT). THEN LOOK BELOW AT THE EXPANDED VIEW OF A SECTION OF CRUST WHICH HAS AN OBVIOUS ARCUATE PRESENTATION:
THERE ARE TWO KINDS OF FAULTS RUNNING THROUGH THE TOROWEEP VALLEY: 1. WELL-KNOWN IS THE NORMAL DOWN-TO-THE WEST FAULT WHICH CROSSES THE GRAND CANYON, AND WHICH CREATES THE 500 OR SO FEET DOWN-DROP FROM EAST TO WEST;
2. LATERAL FAULTING WHICH CREATES THE EROSIONAL WEAKNESSES FOR THE GRAND CANYON AND WHICH MAKES THEM ORIENTED IN ROUGHLY AN E-W PATTERN. THIS FAULT CAN ONLY BE INFERRED FROM THE ROTATIONS OR SHEAR ALONG THE CANYON WALLS, BY LOCATIONS WHERE VULCANISM EXTRUDES, FROM SLICKENSIDES TRACING LATERALLY, OR BY INDICATIONS OF SHEAR OR LARGE-SCALE LENGTHY FRACTURING.
VULCAN'S THRONE IS LOCATED ON THE NORTH SIDE OF THE GRAND CANYON, ABOUT 1/2 KM FROM THE GORGE. ITS LOCATION IS DETERMINED BY THE SHEAR ALONG THE TOROWEEP FAULT, AS IS A VENT ON THE SOUTH SIDE. THESE BASALT VENTS ARE EMPLACED BY THE LATERAL DISPLACEMENT OF THE GREAT FAULT (SHEAR, SINCE IT CREATES THE BRITTLE-FRICTION HEAT IN THE CRUST) AND NOT SO MUCH BY THE VERTICAL DISPLACEMENT:
SO WHAT DO WE KNOW ABOUT THE VARIOUS MOVEMENTS OF LATERAL AND NORMAL FAULTING NEAR THE COLORADO RIVER- MOVING ITS PATH BY SHEAR OF THE BRITTLE ROCKS THROUGH TIME? BELOW ARE SHOWN SOME OF THE ROTATIONS, DISPLACEMENTS, AND SHIFTS OF THE RIVER IN TH LAST 3 MILLION YEARS, ASSUMING THAT THE SHIFT IS 70 KM, AND THAT THE COLORADO PLATEAU IS MOVING AT A RATE OF ABOUT 24 MM/YEAR (FROM MY OTHER CALCULATIONS- SEE 2ND PHOTO BELOW):
DATA ABOVE ARE FOUND BY ANALYZING THE SHIFT OF THE COLORADO RIVER OVER TIME, FINDING THAT BOTH DIVERSIONS TO THE SOUTH OF THE RIVER ARE ABOUT 70 KM IN EXTENT. ALTHOUGH THE RIVER PATH HAS ROTATED SOUTHWARD, ITS GENERAL PATH IS WESTWARD, UNTIL REACHING THE HENDERSON, NV AREA. THEN THE RIVER DRAINS SOUTHWARD, WHICH IS THE LATEST PATH CREATED SOME 3 MILLION YEARS PRIOR. BEFORE THAT, THE RIVER EITHER DRAINED TO THE ATLANTIC BASIN THROUGH PASSAGES SUCH AS THE RIO GRANDE, BUT NOT INTO THE LITTLE COLORADO BASIN- SINCE NO SEDIMENTARY ROCKS OF THE APPROPRIATE AGE HAVE BEEN FOUND THERE:
Colorado River course changes in Tertiary Time
A glance of the map pattern of the great river of the West shows that the general drainage is westward into the Pacific Basin. There are a couple of significant departures from this trend, before reaching a south drainage into the Sea of Cortez, namely the southward rotations in the Grand Canyon- correlating with the great down-dropping faults on the western edge of the Colorado Plateau, CP. These are generally ignored, for interpretation of the historical development of the great river. However the great faults have lateral movement which is smaller than the vertical displacement for a small time interval, but on the scale of millions or years the lateral movement is much more important for Structural Geology understanding.
Usually, the geology culture is dissuaded from recognizing that there is lateral motion, because of their measurements of the vertical displacement along the great circular faults. This is the most obvious, observation, since they can easily find the drop along a scarp. But for lateral movement, it is not so obvious, since the shift of a bed or layer along its horizontal axis may go unnoticed. For example, one can look at a road cut in the Mesozoic outcrops along I-15 in St. George, UT and see that there was no vertical displacement along normal faulting. It is more difficult to see the small thrusting laterally along a layer, and it can be surmised that the view is one of lateral pinchout or tapering of sandbars. Bellow is such a case:
A view of the Colorado River map shows that many rotations have occurred along the trench, and only after understanding the Coriolis Force and its daily rotation of weather cells, ocean currents, and finally arcuate presentations of the Crust of the Earth, can one understand the movement trends and departures from normal trends of the river path. Although Coriolis Tectonics is a small effect, on the order of 1 mm/year, it is continual and persistent- creating large movement over the 1 million year time period. One mm/year is equivalent to 1 kilometer per million years, when assessing the result of continual Coriolis rotations. Watching weather cells by satellite observation allows understanding of the circular nature of cloud movement, while scanning Google Earth allows a view of the circular presentation of movements of the Crust.
LOOK AGAIN AT THE PATTERNS OF VENTS MAKING ARCUATE PRESENTATIONS ON A LARGE SCALE, AND AT A RIGHT-ANGLE VIEW (NORTH IS TO THE RIGHT) OF THE CIRCULAR ARRANGEMENT OF THESE EXTRUSIONS (WHICH INFER THAT THERE WAS ORIGINALLY A CONFLICT WITH TWO CELLS ROTATING IN SAME DIRECTION- CCW VS. CCW).
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