# Tag Info

10

I think the easy answer comes from the Hawaii Department of Land and Natural Resources: Beaches in Hawaii may be made of 'black sand' derived from the erosion of volcanic rocks, of 'white sand' made by marine organisms, or a mixture of both. On the windward side of the Big Island, for example, black sand beaches are very common. The beach at South Point ...

9

I suspect you are referring to the mesas and buttes dotted around the Karoo - the large semi-arid plateau that makes up much of South Africa's interior. These are a product of the glacial and geological history of the region. The flat hills are capped by hard, resistant dolerite. This is solidified lava that was forced between the horizontal strata of the ...

8

Soil color is largely determined by it's composition. There are three main components in soil: Gravel, sand, and silt. In essence, the type of stuff you find in sedimentary rocks. Usually, this is mostly silicate minerals like quartz, feldspar, and mica, and is usually pretty bland in terms of color. In theory, certain silt minerals (olivines for example)...

7

Near the Lake of the Woods, the island swirl or vortex is due to structures in bedrock beneath the lake. The rocks in this area are old and have been folded by tectonic action. The area has either been folded into a dome or a basin, exposing different layers of bedrock. Glacial activity afterwards has 'flattened'the area, and differential erosion within the ...

6

You are correct when you say it is mostly a matter of getting your eye in and getting used to the shapes and types of rock you need to be looking at. Hopefully however the below information will help you find a few more fossils or at least be of interest to you. The main fossil bearing beds in Lyme Regis are from the Jurassic period and formed in a warm sea,...

4

This is Marloes Sand Beach, a classical fossil site. The nicely colored rocks are sandstones of the Silurian age (around 425 million years old). The different dipping angles of the sandstone layers are a result of tectonic processes, which were folding the rocks. Further information about Marloes Sand can be found here

4

The intraplate compression responsible for this uplift has had a couple of explanations over the years; historically, it's been ascribed to Alpine collision, i.e. the collision of the Alpine orogen with the Europe. However Kley & Voight (2008) reviewed evidence and concluded it was the effect of Africa-Iberia-Europe convergence: ... the onset of ...

4

The best I have been able to turn up is the paid BD-logs service, which provides standardised lithology for borehole data. Open Geospatial Consortium data all appears to be listed on the Geoservices page, and does not appear to include a lithological database/lexicon. The French Geological Reference Platform does not appear to include a standalone database. ...

3

As far as I know there are no official data on this. All I can do is give a rough estimate, based upon work and personal interest in about 30 countries, over 40 years. We can say with certainty that everywhere has been mapped at the 1: million scale although, at this 'reconnaissance scale', at least half of the land surface is only sketchily known, with ...

3

I think that notations S$_1$, S$_2$, ..., S$_n$ may well refer to any ordered orogenetic phases producing schistosity in any rock, anywhere, at any time Generally, yes. This is not only true for the Alps, but also for any other orogenic regions in the world (e.g. Himalayas, Arabian-Nubian Shield). Note that the numbering is ($n$) is used very loosely. ...

3

At least speaking for Table Mountain, from when I was at the top, it is actually not as flat as it appears from the surrounding landscape. Table Mountain was formed from horizontal layers of sedimentary deposits. One hypothesis is that a collision between Africa and another oceanic plate occurred around 250 million years ago. The collision upheaved these ...

2

I'd like to add to Gordon's answer by emphasising that a geological map (in the classical case of mapping rock outcrops in colour) is an interpretation of the surface, occasionally with the aid of other methods such as drilling or geophysics. Being an interpretation, the amount of detail varies. One map can say that one area is just a huge block of granite, ...

2

As a very general rule, I'd look for rocks deposited in low energy environment, e.g. shale and some carbonates. Waves often destroys remains of animals in sand, so massive sandstones wouldn't be my first place to look. When you find one fossil, continue to look in the same layer.

2

In general, a good answer to "where can I learn the basic concepts of X" is "a textbook on X". For sedimentary concepts, you might try Nichols (2009), for instance. Academic papers are a publication vehicle for new research, so you'll seldom find much introductory material in them. For terms like "intracratonic" and "intramontane", you might also find it ...

1

Your local university likely has a small natural history museum in its geology department. These are generally free and filled with information regarding local geology. I'd start there.....and bring your rocks; the attendant might be able to help you find someone who can identify your rocks.

1

" Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic Continental Shelf?" There's a USGS group at Woods Hole that's done a bit of work on this back in 2004: A catastrophic meltwater flood event and the formation of the ...

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