17 votes
Accepted

What is this weird looking structure in Ethiopian desert?

Zoom in for the clues. The lines are not radiating out from the village, but from the cattle kraals. These kraals are irregular enclosures built of acacia thorn, agave and other thorny bushes. The ...
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 ...
  • 6,640
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. ...
6 votes
Accepted

Geomorphological feature identification

The place is called Urðarháls. I could not find much information about it in the scientific literature... It is mentioned in Sigmarsson & Halldórsson (2015): they say it's an interglacial basaltic ...
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 ...
4 votes
Accepted

What causes this arc in the night sky where the background is brighter on one side than the other?

What is happening here? Photoshop! The number of visible satellites plummets towards the middle of the night when more satellites fall into the shadow of the Earth, represented by the dark area on ...
  • 263
3 votes
Accepted

How these rock features form?

That's a conglomerate. The infilled fractures will have formed when it was buried at depth and thus under considerable pressure. The substrate may be physically softer or it may be more chemically ...
  • 4,240
3 votes

Geomorphological feature identification

According to this geological map of iceland it is the Urðarháls, an interglacial shield, i.e. a dolomite shield volcano that got scraped by glacial activity The hole in the middle is the pit crater. ...
  • 216
2 votes

What is this geological formation in the Santa Cruz mountains that looks like a cave interior?

Well given that travertine springs trail is right next door, in castle rocks state park I am going to guess travertine. Which is a calcium carbonate mineral deposited from geothermal springs, hot ...
  • 6,640
2 votes

What is this fossil found in flint in Kent?

Definitely an echinoid (sea urchin) and they are often found in the flints in the chalk cliffs along the south coast of the UK. Seaford in Sussex is particularly well known for these types of fossils.
  • 91
2 votes

What type of clouds are these?

Mostly stratocumulus with a scattering of emergent cumulus towers which have been lofted by strong internal convection cells.
1 vote

Looking for Rock/Mineral Identification Flowchart

From my own experience of being a geologist for close to fifteen years, flow charts like that are of very limited use. The truth that you probably did not want to hear, is that it takes years of ...
  • 22.6k

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