20
votes
Why are many fossils found in deserts?
Bones don't last very long in jungles. Or in forests. Or almost anywhere.
Fossils are the consequence of one highly unlikely fluke after another. Darwin himself commented on this. It takes just-right ...
- 23.1k
15
votes
What are these lines on this stone?
You don't say which lake, but these are almost certainly crinoid stem fossils. Crinoids, or sea lilies, are echinoderms (relatives of starfish and sea urchins) that anchor themselves to the sea floor ...
- 3,548
15
votes
Why are many fossils found in deserts?
Because you find fossils by looking at exposed bedrock, deserts by their nature often have huge expanses of exposed bedrock. The lack of plants is also a big benefit, plant roots tend to destroy ...
- 6,878
10
votes
Accepted
Why are many fossils found in deserts?
I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ...
- 626
9
votes
Accepted
What is the oldest fossil on Earth?
The oldest undisputed fossil are Stromatolites, bacterial mats, the oldest of which are dated ay 3.7 billion years ago. The key term here is undisputed, there are other possible fossils but it is very ...
- 6,878
9
votes
Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?
The short answer is no, because we always have some constraint of how old something is. Sometimes we have fossils with large date error bars, and often we do not know for how long that species ...
- 1,035
9
votes
What is this fossil found in flint in Kent?
That is a sea urchin (echinoid) or at least part of one. the pattern of plates is fairly distinctive. 2 rows of small plates alternating with 2 rows of large plates. I am not familiar enough with ...
- 6,878
8
votes
Accepted
What is Oligo-Miocene radiation?
The ‘Oligo-Miocene’ part
The Oligocene and the Miocene are epochs of geological time. The Oligocene lasted from ~33.9 million years ago to ~23 million years ago; the Miocene followed immediately ...
- 5,431
8
votes
Accepted
What is this fossil? What is this crystal?
Yes, this is a rather nice find; an ammonite of the Jurassic in central Europe. Given the size of the specimen, and its appearance, this appears to be of the species Cardioceras, or Perisphinctes. ...
- 96
7
votes
Accepted
What are Ordovican trace fossils, and what do they look like?
Trace fossils are marks or things left behind by living things do their thing, they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive ...
- 6,878
7
votes
Accepted
Curious natural patterns on the surface of basalt blocks that make up the sidewalk
These are most likely manganese dendrites. It is not a fossil, and not organic. These usually form in cracks in rocks, and most likely this slab was broken along an existing crack.
You can read more ...
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6
votes
Who can it belong to? fossil tooth
The geology of Lithuania is pretty complex - ice ages could have brought nearly anything. The fossil belongs to Rugose corals - an extinct order of solitary and colonial corals that were abundant in ...
- 549
6
votes
Aligator or Dinosaur Fossil skin type rock
I agree with commentator @John, this is a fossil coral. The coral animal (the polyp) builds a column, and as it ages it closes off the bottom and extends the upper lip. In some of the views you see ...
- 822
6
votes
Why cannot people burn all the atmospheric oxygen?
Photosynthesis has not stopped. It happens all the time, splitting water and carbon dioxide, and producing oxygen and carbohydrates. Likewise, organic matter rots and decomposes all the time, ...
- 2,028
6
votes
Accepted
I have found this fossil tooth, could it be pliosaur ? Or maybe theropod?
Most likely plesiosaur. That fluted structure is indicative of marine reptile teeth. My first guess was mosasaur but their are a lot of plesiosaurs from that formation so I would go with that. It is ...
- 6,878
6
votes
Are marine fossils in the mountain happens due to lower sea levels?
Leonardo was wrong about this. It is not due to sea level dropping (except in very isolated cases), it's due to the land rising. Sedimentary rocks that form in sea beds are often uplifted by ...
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5
votes
Accepted
Why the $\delta \, ^{18}\text{O}$ in foraminifera shells decrease with temperature even if the oceanic $\delta \, ^{18}\text{O}$ stay constant?
That is because the chemical reactivity of $^{18}\text{O}$ is slightly higher than that of $^{16}\text{O}$. For that reason, the biochemical reactions that produce calcium carbonate in foraminifera ...
- 17.6k
5
votes
Accepted
What type of mammal does this fossil tooth belong to?
It's an entelodont, South Dakota is famous for it's Oligocene mammalian faunas which include entelodonts such as Archaeotherium and Daeodon.
here is an http://i.ebayimg.com/images/i/181202162847-0-1/...
- 1,339
5
votes
Accepted
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'...
- 23.1k
5
votes
Accepted
How old are Pecten fossils in general?
Pectens seem to have evolved from Chlamys in the late Eocene or early Oligocene. The coarseness and rib spacing of Vertipectens has been slowly evolving since the early and Mid-Miocene, so they have ...
- 14.2k
5
votes
Why don't animals rot when trapped in amber?
things need to be exposed to bacteria to rot, amber produces a perfect form fitting seal and has several antimicrobial properties to boot killing off bacteria that is already present. Even microbes ...
- 6,878
5
votes
Accepted
Fossil from North Norfolk coast, UK
The round one is a belemnite... The grid-shaped fossil is a bryozoan. Bryozoans were (and are) marine colony building organisms often encrusting shells and other hardgrounds in the oceans. There are ...
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5
votes
Have fossils ever been found in the asphalt lakes of Trinidad and Venezuela?
Trinidad
Quote from https://www.smithsonianmag.com/travel/trinidad-and-tobago-nature-and-scientific-wonders-18329129/
Quite an oddity sits in La Brea in South Trinidad—the world's largest asphalt ...
5
votes
Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?
Yes it does happen, and we know when and why it happens.
Bad collection. The most common reason is because of bad collection methods. Some times laypeople collect fossils without recording where or ...
- 6,878
5
votes
Are there any rock recognition practices or games?
You could look at this and similar apps but they're more from the other side, you have a rock here's what you need to ask yourself to ID it. I don't use anything like that myself because I memorised ...
- 4,260
5
votes
Which trilobite species are these?
The first specimen seems more like Elrathia sp. Features noted that were similar are small eyes, small projecting genal spine (extreme left and right at the posterior margin of the cephalon), and ...
- 51
5
votes
Accepted
Is this a fossil?
Yes it could be a fossil. Btw. it is called a sand dollar.
The term sand dollar refers to several species of flattened burrowing sea urchins that belong to the order Clypeasteroidea. Sand dollars, ...
- 1,906
4
votes
Why cannot people burn all the atmospheric oxygen?
If I understand it right, you are assuming that in the beginning we had CO2, which was then split to organic carbon and O2 via photosynthesis. And now you are asking if it's possible to reverse all of ...
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