Wednesday, June 5, 2013

Tala Point Part I: Advancing Shorelines, Boat Ruins and Iron

I had a small project to assess at Ludlow Bay in Jefferson County. With a low tide and mostly sunshine combined with other site work having been done I allowed my curiosity to propel me along the shore to Tala Point as I had not previously made that shoreline trek. AERIAL VIEW. All together I hiked about 4 miles of beach. So a few notes from the hike broken into parts.

The first thing that generated curiosity was a low bank area of peat soils that was being eroded and encroached on by the sandy beach.

Organic soils eroded and encroached.

There are a number of possible explanations. Perhaps it was an estuary that had previously been protected by a spit, or the organic layer was the result of woody material placed as fill during early settlement days or more exiting there is some tectonic process at work here causing this bit of shore to subside or it could be a spot where sea level rise is a bit more evident or (lots of ors) a combination of the alternatives.

A bit further on I came across some western red cedars that suggests the beach and hence relative water levels may be rising.

Cedar at the top part of the beach

Cedar stump (the stump appeared to be in place and not drift wood)

Looking north towards Tala point
Net shore drift is towards the the picture taker as can be seen by sand built up behind log across the beach.

The next curiosity was what I thought might be some hard sediment or bedrock forming a platform along the shoreline. Instead it turned out to be the last remnants of a wooden ship.

Wooden ship ruins with port Ludlow resort in distance across the bay.

A shore feature I have seen before but is still always a curiosity and in this case was rather spectacular is iron precipitation on the beach surface.

Superficially the iron precipitation appears like it may be blobs of oil or fuel

But on a close look note the cracked surface of the iron (and possibly manganese) precipitation surface

A broader view of the close up from above

This stretch of shore had a broad filled former shoreline estuary behind the beach. The fill was at least partially natural, but given the history of the area and the ships some of the fill may have been anthropogenic. As groundwater passes slowly through the organic zone the oxygen is depleted and iron and other metals dissolve and are mobilized. When the water reaches the surface at the beach the oxygen in the air causes the metals to precipitate creating a mirror like surface that looks at first glance like the interference and sheen like effect of oil.

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