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Thursday, 26 March 2015

Caged glacial erratic in New Jersey

 I came across this rather sad picture of a small glacial erratic in a cage.  Who on earth did that?  A bit over the top, don't you think?  Poor thing -- I feel sorry for it.






Caged nephelene syenite erratic found along the Glacial Geology Trail in Stokes State Forest, New Jersey. This erratic was glacially transported from a small body of syenite sometime during the last ice age, about 18,000 years ago. The syenite outcrop lies 1.5 to 3.5 miles northeast of the erratic on the east side of Kittatinny Mountain and about 200 to 330 feet below its summit.

11 comments:

Jon Morris said...

Type 2 rebar that is. So done in the later part of the 20th century. Good job on the welds.

BRIAN JOHN said...

Is there no end to the expertise on display on this blog.....? What a talented lot we are!

TonyH said...

We could do with a Glacial Geology Trail, not just in New Jersey, but also in the Wiltshire/ Somerset vicinity. I have mentioned to you, Brian, there is a Geology lady, possibly based at Bath University, who has created her own Varied - Stones Stone Circle for public viewing somewhere near Box, I believe. Have forgotten her name. Unfortunately, it hasn't anything to do with glacial erratics.

However, you recently (Feb/ March 2015) did another Post on the Bathampton area map showing glacial features first identified by the late Geoff Kellaway. I have remarked, as has our Blogger (Phil? - he of the Mendip Caves investigations) that the British Geological Survey has put glacial features on its latest maps of that area. Bathampton is only around 25 miles from Stonehenge as the crow flies/ flew, so that's getting closer than many archaeologist - nay - sayers would claim!

What I'd like to know is: are the glacial features recognised to the WEST of Bath; and also further EAST of Bathampton/ Box?

A G said...

Its Alex not Phil? No offence!

Thank god we're a more enlightened bunch and allow our glacial erratics to roam free on Salisbury Plain!

Alex Gee
patron of the campaign to "Free the New Jersey One!"

AG said...

I'd say the key to the Bathampton situation,are the valleys to the Southwest, West, Northwest, North and Northeast!

The sides of these valleys are all landslipped caused by excessively rapid overdeepening.Most probably caused by glacial meltwater.

The location of the landslips could well be a record of the position of the greatest extent of the Anglian Glacier and its retreat?

There are no overdeepened valleys to the southeast.




Constantinos Ragazas said...

Alex,

Interesting observation re landslipped valleys of Bathampton. You say these valleys are to the southwest, west, northwest etc. but not to the southeast. What does that tell us about the direction of the glacier meltwater torrents? Which you argue had to be rapid and vast?

If the glaciers were retreating in a northwest, north direction, their meltwater streams would likely be flowing in a southeast , east direction (depending on the local topography, of course). But under normal circumstances, would such meltwater streams be as rapid and vast?

On the other hand, a collapsing glacier lake will certainly create such vast and rapid torrents. And if such lake formed by an encroaching Irish Sea Glacier along the Bristol coast, the direction of such rapid torrents would be towards southwest, west.

Since you know the lay of the land there, is such direction of glacier / lake meltwater torrents consistent with these landsliipped valleys and with the larger topography of this area? I am assuming all the meltwater eventually drained at the Bristol Channel.

How do these landslipped valleys comport with your findings of Mendips caves?

I know! I am once again "armchair geologizing". Forgive me if I am way off the mark on this!

Kostas

BRIAN JOHN said...

Interesting idea that many valleys are "overdeepened" and contain landslips -- except for the valleys to the SE. Must look into that.....

As for glacial lakes, yes, an ice front if it impinges on a reverse slope will tend to trap meltwater, and the lake thus formed will have to escape somewhere. Again more evidence needed....

TonyH said...

Alex

Sorry I called you Phil! A Senior moment!

Are there not landslips up the Avon valley - more or less SOUTH of Bathampton, on the east side of the river, near Warleigh, Conkwell, etc? Would you agree these may be within your category of excessive rapid overdeepening? I would value your opinion. That might take any hypothetical furthest extent of the Anglian glaciation closer to Winsley, Limpley Stoke and Bradford - on - Avon.

Alex Gee said...

Brian and Tony H
Apologies for the tardy reply.

Tony H. Definitely My senior moment too. I meant to include the area to the south, where indeed Glacial deposits are extant on the high ground above these valleys.

The reason for my noting this anomaly is that the same Jurassic scarp extends from Lime Regis to Yorkshire. Despite the geological strata being of similar lithology,

North of Somerset, Major Landslipping near the scarp, only seems to be mapped where the influence of glacial processes has been proven?

Go figure?






Alex Gee said...

Brian
A rather elegant theory was advanced in this paper http://www.ubss.org.uk/resources/proceedings/vol20/UBSS_Proc_20_2_91-108.pdf

That the the landslipping along the Claverton gorge was caused by rapid overdeepening caused by the capture of the headwaters of the River Thames by the River Avon.

It is a most plausible hypothesis, but does not explain the rapid overdeepening and landslipping in the other valleys in the same area.

Some of which have little or no catchment area?

Some of which end in the wind gaps in the cotswold scarp referenced by the late Kellaway, in his papers on glaciation.

Be most interested in your thoughts!




Alex Gee said...

Brian
A rather elegant theory was advanced in this paper http://www.ubss.org.uk/resources/proceedings/vol20/UBSS_Proc_20_2_91-108.pdf

That the the landslipping along the Claverton gorge was caused by rapid overdeepening caused by the capture of the headwaters of the River Thames by the River Avon.

It is a most plausible hypothesis, but does not explain the rapid overdeepening and landslipping in the other valleys in the same area.

Some of which have little or no catchment area?

Some of which end in the wind gaps in the cotswold scarp referenced by the late Kellaway, in his papers on glaciation.

Be most interested in your thoughts!