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49 votes
Accepted

Is there sand in Antarctica?

Yes. In fact, there are sand-dunes in Antarctica [1:15].
Christopher Klaus's user avatar
18 votes

How much does sea level rise due to sediment deposition?

In a 1983 Journal of Geology paper by Milliman and Meade, "World-Wide Delivery of River Sediment to the Oceans" (link) it is estimated that the world's rivers carry about $13.5\times 10^9$ tonnes of ...
Floris's user avatar
  • 1,384
15 votes

Are fossil fuels really formed from fossils?

Let's look at this. A very large number of points for one question. First, the solar system. We do not see any hydrocarbons in the inner solar system (Mercury to Mars). This is because in this region ...
Andrew Jon Dodds's user avatar
14 votes

Is there sand in Antarctica?

This LiveScience article suggests the areas aren't major: The scant areas that are free of snow and ice make up less than 0.4 percent of the continental land mass. In places there, the wind has built ...
JeopardyTempest's user avatar
10 votes
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Large scale structures in the Sahara – what are they?

These features are created by the wind.You will note that the upper left portion has a small dark spot. This is known as Waw al-Namus, or the "Oasis of Mosquitoes." It has a path of material in the ...
Douglas J E Barnes's user avatar
9 votes
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What is the earliest sedimentation we know of?

The oldest known metasedimentary rocks are about 3.8 billion years old, formed in the Eoarchaean era. 'Metasedimentary' just means they have been metamorphosed, so they started out as sediments. They ...
Matt Hall's user avatar
  • 11k
8 votes
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No sedimentation without water?

Not all sediments are deposited in water, but water is important in the formation of most sedimentary rocks. If we're just thinking about the deposition of the sediment, then we don't necessarily ...
Matt Hall's user avatar
  • 11k
7 votes
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What factors bring sand into or out of the beach?

The amount of sand on the beach at any one time is a dynamic quasi-equilibrium between a whole raft of processes. These include wave power, frequency and direction, seabed angle, longshore drift, rips ...
Gordon Stanger's user avatar
7 votes

Do you have any informations about fossil-rich cherts from Scandinavia?

What you are looking for is information about the "Oslofeltet" (Oslo-field) in Norway (dated to be from the Ordovicium period, 443 - 488 million years old). This is a concentrated field of of fossils. ...
trond hansen's user avatar
  • 1,878
7 votes

Are we observing sedimentary rock formation today?

The transformation of sand into sandstone per se cannot be directly witnessed, as it's happening deep in the earth. However, there are types of cementation that happen quickly and in plain view: A ...
Spencer's user avatar
  • 3,578
6 votes

What caused this waterfall to have rounded formations?

Looks like alkali earths ( Ca, Ba , etc.) carbonates deposited from a supersaturated hot spring. As the water emerges from the spring, carbon dioxide leaves the water and the water cools, it ...
blacksmith37's user avatar
  • 1,043
6 votes

What makes sand dunes shaped asymmetrically?

Saltation cannot proceed up a steeper slope under the wind conditions that prevail in the particular dune's formation. Dunes are basically traffic pile ups for wind driven sand grains, the slip face ...
Ash's user avatar
  • 4,270
5 votes
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A sedimentary rock with only minerals

This is a really bad question, because all three can lack fossils, or all three can have fossils. The definition of "minerals" is also a bit unclear, because fossils are also made out of minerals. I'...
Gimelist's user avatar
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5 votes
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Do any rivers deposit sediment in their deltas fast enough to counteract sea level rise?

This is a hugely complex subject for which a categorical answer requires detailed river basin modelling and process calibration. The short answer is that in the short term many rivers deposit sediment ...
Gordon Stanger's user avatar
5 votes

What factors bring sand into or out of the beach?

There's a huge literature on this problem, and depending on who you ask you will get different answers. I'll come at it from the geomorphology perspective. The most uninformative explanation is that ...
Z W's user avatar
  • 432
5 votes

Are fossil fuels really formed from fossils?

The definition of a fossil is "evidence of past life preserved by geologic processes". By this definition a coal bed is itself a fossil since it is the preserved organic matter from an ancient ...
verisimilidude's user avatar
5 votes
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In an Earth-like planet with no history of carbon-based life forms, would there be limestone?

I'd have to say, yes. Once life evolved in the world's oceans, the vast majority of limestone formation has been through the organic process. However, before life did evolve, limestone formed through ...
BillDOe's user avatar
  • 2,187
4 votes

What is the maximum grain size of a sediment that can be point counted using a standard thin section?

you might have guessed: There is no such an easy answer as a precise, always valid maximum grain size. Point counting is an upscaling technique. It works when the sample area you inspect is >= to the ...
Bendaua's user avatar
  • 231
4 votes

What, exactly, is angle of repose, and where is it in this image?

Geological materials such as sediments are never totally homogeneous. There will always be softer and harder regions within sedimentary deposits. The fact that erosion channels have been created is ...
Fred's user avatar
  • 24.7k
4 votes

Is Radiocarbon dating flawed?

I will preface this by saying that I am not particularly familiar with radiocarbon dating techniques, and therefore the minutiae are somewhat lost on me. However, as someone who works with several ...
desander's user avatar
  • 415
3 votes
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The grains of the parabolic dunes

"Sand" is generally made up of whatever eroded rock type is nearby, minus the most easily eroded (and windswept) components. Typically, dunes are made up of highly resistant quartz grains, like the ...
Knob Scratcher's user avatar
3 votes
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How this sedimentary rock is made?

The rock you show is a conglomerate - it contains a substantial amount of clasts (your pieces) that are gravel or larger size. The pieces have been cemented together into a new rock - kind of like ...
haresfur's user avatar
  • 4,419
3 votes
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Is Desert Sandstone a chemical sedimentary rock?

No, it's not. The overwhelming majority of the material in the rock is clastic, not chemical. Chemical sedimentary rocks are rocks where (almost) all of the material was precipitated, such as ...
Gimelist's user avatar
  • 23.1k
3 votes

Geology: facies v. formations

A formation is a unit of stratigraphy. It refers to a set of sedimentary layers which are somehow distinct from those above and below them in the stratigraphic sequence. This may be because they have ...
bon's user avatar
  • 2,211
3 votes

Geology: facies v. formations

A "sedimentary facies" is just a descriptive term. For example all rocks (anywhere in the world) that have similar characteristics (e.g. mineralogy, color, grain size distribution, sedimentary ...
Antonio's user avatar
  • 947
3 votes

How are chenier ridges and strand plains formed at wave dominated coastlines?

The following sources helped me understand these landforms - hopefully they can help you too :) From the Miranda Shorebird Centre: The Miranda-Kaiaua cheniers are first formed as sand and cockle-...
EinsteinFrizz's user avatar
3 votes
Accepted

How are sand blocks formed?

There are two "normal" mechanisms for this effect: Clay bonding, the beach sand contains a small fraction of clay particles which bond to the grain surfaces and hold the sand together when dry, this ...
Ash's user avatar
  • 4,270
3 votes

How are the Scala dei Turchi staircases formed?

There's no need to invoke stretching here. This is just a simple case of dipping sedimentary beds which have been eroded by the sea. The stepped geometry may be caused by small variations in the ...
bon's user avatar
  • 2,211
3 votes

Is there sand in Antarctica?

The simple answer is: of course. Sand is defined as a lose granular material with grains between 0.074 and 4.75 mm diameter (US definition) or 0.0625 to 0.2 mm (Wentworth, 1922, scale). There is also ...
Peter Jansson's user avatar

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