The regional left-lateral fault cutting Whidbey Island on the north part of the island, near Deception Pass, has been investigated by the USGS- published in professional publication 1643 (Johnson, S.Y. et al, 2001). This is a complicated fault system, exhibiting several splays- one of which may be seen directly on a geographical map as the Silver Creek running SE from Silver Lake.
That the highest point on the island, 541 feet in elevation, occurs near the highest lake, should have caught the attention of someone looking for anomalies. This is a dead giveaway for a rising area, rotating CCW and yielding arcuate cliffs-convex to the east. Some of the splays may be seen on the beaches of this circular part of the island, near Borgman Lane and Polnell tombolo as slickensides and iron-bearing springs.
Below are three Google photos of the north side of the rotation, at Dugualla Bay and the sub-sea dike controlled sink (pond):
Notice that for two rising areas, rotating CCW, there must be a CW cell between them, or else there would be geothermally-derived heat of friction (resulting in warm springs). That there is iron on the slickensides of Polnell tombolo, and iron in the cold springs on the east side near Borgman Road indicates that there is a chemical anomaly.
These photos demonstrate that not only is there rotation of the Crust beside a lateral fault (named RC for reactionary cell- a DRAGGED ROTATION), but that the fault may be isolated on the map by the circular pattern of rivers, creeks, drainages, and coastlines. This is a valuable tool for anyone looking for the patterns of anomalies, to research shear and thrusting of the Crust. The valuable feature being demonstrated above is that the time scale for recognizable events is for the 10 k.years period- not requiring millions of years. Recall that the ice age terminated in this area about 14 k.years ago, and that there has been rebound since. This means that sinking creates CW rotation originally with the ice weight, and that now there is CCW rotation with the rebound (rising) of the Crust- wherever the ice created significant thicknesses of ice (consequently added mass and weight, or sinking of the CRUST).
BELOW ARE PHOTOS OF THE HIKE MADE ABOUT DUGUALLA BAY, JUNE 27TH- WHICH IS A SINK, BORDERED ON NORTH AND SOUTH SIDES BY UPLIFTS, WITH MANY SPRINGS. NOTICE THE ANOMALOUS SCARPS AND ASSOCIATED ROTATIONS AND SPRINGS:
THE UTSALADY FAULT SYSTEM OF NORTH WHIDBEY ISLAND SHOWS VARIOUS MOVEMENTS ALONG FAULTS (DUE TO REBOUND AFTER THE ICE AGE AND BEFOREHAND, WITH SINKING DUE TO WEIGHT OF THE 1 KM OF ICE THICKNESS 
ENLARGING,
BELOW IS FIDALGO ISLAND, THE NEXT ISLAND TO THE NORTH OF WHIDBEY, AND WHICH EXHIBITS A VERTICAL SCARP OF METASEDIMENTS. WE WILL INVESTIGATE THIS AGAIN, NEXT, TO LOOK FOR SLICKENSIDES IN THIS DIFFICULT TO SCALE FAULT PLANE:
Below are shown how slickensides are initiated along sheared and uplifted areas on Whidbey Island, with a view of understanding how this mechanism proceeds:
BELOW IS THE THRUST, LATERALLY, OF INTERGLACIAL SILT, TILL, AND SEDIMENTS WHICH FORM THE INITIAL PRE-STONE CONTAINING THE EARLY SLICKENSIDES COMPRESSION. NOTICE THAT THERE IS A DARK CHERT-LIKE (NOT AS HARD) INTERIOR AND A SOFT SILT COVERING. THESE SLICKS ARE USUALLY SHAPED LIKE AN OVAL LATH, TAPERING TO AN EDGE ON ALL SIDES, AND SOFT (BREAKABLE WITH THE HAND) QUATERNARY NODULES. THE PHOTO BELOW SHOWS THAT THEY FORM AT THE HIGH-STRESS LOCATIONS OF LATERALLY-MOVING SHEAR PLANES:
BELOW ARE PHOTOS TAKEN OF THE CLIFFS SOUTH OF HONEYMOON LAKE CLUBHOUSE, SHOWING THE CIRCULAR SHEAR AND FRACTURING FOR THIS ACTIVELY-MOVING PART OF THE ISLAND:
THIS IS AN ON-GOING FIELD INVESTIGATION OF WHIDBEY ISLAND- WALKING AND OBSERVING THE 150 MILES OF BEACH, WHICH IS MOSTLY OPEN TO ANYONE ACCESSING A COUNTY ENTRANCE BEACH. ALTHOUGH GEOLOGISTS CLAIM THAT THIS IS "DIRT GEOLOGY", I HAVE FOUND THAT THE AREA IS INVALUABLE FOR ANYONE WANTING TO UNDERSTAND THE MOVEMENTS AND STRUCTURAL GEOLOGY OF THE CRUST. WHIDBEY ISLAND DEMONSTRATES AND PORTRAYS THE ORIGINAL SINKING MOVEMENTS OF THE CRUST UNDER THE ICE, AND THEN THE REBOUND RISING (AND ROTATING TRACES, CCW) OF LATER ICE-FREE PLEISTOCENE SEDIMENTS.
No comments:
Post a Comment