Buy

Books
Click images for more details

Support

 

Twitter
Recent comments
Recent posts
Currently discussing
Links

A few sites I've stumbled across recently....

Powered by Squarespace

Unthreaded

You have lost your "open mind"
I’m not sure he ever had one to lose, Minty.

Feb 23, 2018 at 12:27 PM | Registered CommenterRadical Rodent

GolfCharlie. The suction effect you mention could become quite atrocious when trying to extract a 10-ft core. Often we had to use a tripod (with legs resting on floats) and winch it out. Everyone got disgustingly covered in white mud (no need for sun-screen). Happy days! This has brought those wonderful times flooding back.

EM. I hope you and others find that Wanless reference of interest in connection with sealevel rise and effects of hurricanes. What is not mentioned is that normal hurricanes do not cause the wholesale movement of sediment recorded in South Florida. These must be due to super hurricanes, the like of which have not been seen in recent centuries.

Feb 23, 2018 at 12:24 PM | Unregistered CommenterSupertroll

Lapogus

I found a pdf with this exercise.

The tide generating force can be calculated using the following equation:
F = 2GM1M2a/R^3
Where:
F = tide-generating force felt by the Earth due to another object in
space.
M1 = mass of the Earth = 5.98 x 1024 kg
M2 = mass of the object in space
R = distance between the Earth and object (in meters)
G = Universal gravitational constant = 6.6720 x 10-11 m3/kg*s2
a = radius of the Earth = 6400 km

1. Calculate the tide-generating force due to the Sun, and the force due to
the Moon.
Use the following numbers to make this calculation:
Mm = mass of Moon = 7.52 x 1022 kg
Ms = mass of Sun = 1.78 x 1030 kg
Rm = distance between Moon and Earth = 3.90 x 105
km
Rs = distance between Sun and Earth = 1.50 x 108
km.

I calculated the total tidal force generated by the Moon/Earth system as 6.2*10^18 Newtons.

On 1kg of seawater that force is 1.03*10^-6 Newtons.

You calculated a lateral force for Greenland as 0.0009045 Newtons. ie 9*10^-4 Newtons at 500 km.

If the Greenland ice sheet exerts a tidal generating force on the local sea area two orders of magnitude larger than that of the Moon, It seems reasonable that this can raise the local sea level as the Moon raises tides.

Please check my calculation. As Supertroll pointed out, I have a reputation here for power of ten errors.

Feb 23, 2018 at 12:10 PM | Unregistered CommenterEntropic man

Feb 23, 2018 at 11:47 AM | Supertroll

"My intuition is that it is impossible.

Feb 23, 2018 at 10:20 AM | Entropic man"

Climate Science Intuition: NIL v. Practical Experience: TWO

Feb 23, 2018 at 12:07 PM | Unregistered Commentergolf charlie

GolfCharlie. Always interested in other people's methods. For muds with very high water contents I have read about a method similar to that you mention - push down connected piping and freeze sediment before coring. Ice crystal growth probably destroys or disturbs layering but not the vertical distribution of samples. There is absolutely no reason why upper parts of thixotropic mud bottoms of lakes cannot be sampled in sequence or as entire sediment cores. EM is just about 40 years out of date.

Feb 23, 2018 at 12:06 PM | Unregistered CommenterSupertroll

Feb 23, 2018 at 10:23 AM | golf charlie
Same choice for me at that age, same decision however it was a hard choice and after education was finished I spent a lot of time (and some money) filling in the history I was interested in. As far as I can see the present curriculum covers neither Geography nor History to the detriment of the country.

Feb 23, 2018 at 12:03 PM | Unregistered CommenterUibhist a Tuath

EM. You attach a clasping grip with an attached pair of handles to a 10-12 ft length of 12cm diameter irrigation pipe. Stand the pipe vertically above the sediment surface to be sampled, balancing it using the handles. Ram the pipe downwards into the sediment by pulling onto the handles as fast as you can. Place a rubber cap over the end of the pipe creating a vacuum as you pull out the tube with its contained sediment core, using the handles. Place another rubber cap on other end of pipe. Transfer to lab for impregnation.
The speed with which the pipe is pushed into the sediment prevents most of the water from moving so preserving layering and other structures. In a good core the only disturbance occurs within a centimetre of the irrigation pipe, leaving most of the core undisturbed. Compactional shortening is almost non-existent (unless the core is extruded on site).
Initially we sharpened the end of the pipe, but experience showed this to be unnecessary.
If the sediment resists being penetrated using muscle power alone, a vibrocore device must be used - but we are not discussing this type of sediment.

For short lengths of core (topmost 20-25cm) just ram a short length of plastic tubing directly into top sediment, cap end and pull out - nothing could be simpler.

Note that in that reference I gave you, at one locality the sediments cored were calculated to be composed of 90% water.

Feb 23, 2018 at 11:47 AM | Unregistered CommenterSupertroll

They are also trained to attempt to minimise the effect of their own biases. Good practice is to collect as much data from as many sources as possible and try to find a hypothesis which embraces them all.

It would be a gross insult to a historian to suggest that their bias had influenced the interpretation of the data, yet you are quite happy to accuse an entire scientific profession of doing the same.

Feb 23, 2018 at 9:52 AM | Entropic man

Lamb v Mann in a nutshell.

Why do you prefer Mann, and insult history, geography, archaeology, science etc. The IPCC accepted Lamb, then Mann. Now they have dropped Mann, you and Climate Science are stuck with Mann.

Mann is Unsustainable. This is neither Green, nor Politically Correct.

Feb 23, 2018 at 11:17 AM | Unregistered Commentergolf charlie

Supertroll
How do you collect cores from mud soft enough to flow while preserving the layering?
My intuition is that it is impossible.
Feb 23, 2018 at 10:20 AM | Entropic man

Supertroll has done it so can provide his explanation.

A technique I have used, involves a large hollow apple corer, driven or drilled. As with ice cores, samples can be retieved whole. Alternatively, samples can be extracted from within the core that is protected by the metal casing.

Depending on purpose, depth and location etc, dewatering can be used. Drill 6 holes in a circle around the desired location, drop sludge pumps down the holes and run them for hours/weeks as appropriate, then core or drill samples from the centre.

https://theconstructor.org/practical-guide/methods-of-dewatering-excavation-construction-site/13849/

When core sampling saturated "liquid" soils, the problem of extraction is the suction dragging/holding the sample in its position (like trying to get your welly out of mud), rather than liquidity + gravity causing it to flow.

Feb 23, 2018 at 10:55 AM | Unregistered Commentergolf charlie

Feb 23, 2018 at 8:59 AM | Mark Hodgson & Supertroll

Aged 14, I had to choose either History or Geography O Level to study. I chose Geography. I have never regretted it.

Since then, I have enjoyed learning about the bits of History that interested me, and/or were relevant to work I was involved with. The multiple methodologies used by https://en.m.wikipedia.org/wiki/Hubert_Lamb keep proving themselves superior to the single method used by Mann.

Dendrochronology has been a massive leap for Historians and Archaeologists, in establishing the AGE of timber, by recording how good or bad a series of growing season were. It remains incapable of establishing WHY a particular growing season was better or worse.

I prefer the Means, Method, and Motive of Lamb over Mann. Mann was driven by incentive, to arrive at a particular conclusion.

Feb 23, 2018 at 10:23 AM | Unregistered Commentergolf charlie

PostCreate a New Post

Enter your information below to create a new post.
Author Email (optional):
Author URL (optional):
Post:
 
Some HTML allowed: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <code> <em> <i> <strike> <strong>