Questions tagged [rocks]

Questions about rock types, formation, chemistry, and physics. If you just want help identifying a rock please use the tag "identification-request".

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15
votes
2answers
45k views

Are the processes of the rock cycle currently in dynamic equilibrium?

The standard representation of the rock cycle usually looks like this: Does each stage of the rock cycle currently balance? That is, are the various processes in dynamic equilibrium, so that the ...
17
votes
4answers
14k views

What was the first rock in the rock cycle?

I am an undergraduate student but I am a tutor at a High School, and one student asked me. Attempting to explain the rock cycle "if one rock turns into the other then which came first" my gut is ...
6
votes
0answers
160 views

Basalt vs. columnar basalt

I recently visited a cliff on the south coast of Ulva in the Inner Hebrides where there are ~10m thick flows of columnar basalt. The columnar basalt forming most of the cliff is sandwiched between ...
1
vote
1answer
367 views

Oldest to Newest Bedrock in the USA “road trip”

I am supposed to design a road trip (using major highways) across North America. I have to design a route that starts with the oldest rock of Archean age and finishes with the youngest rock of ...
12
votes
1answer
454 views

Formation of limestone without living organisms?

Limestones are formed mostly from skeletal fragments of marine organisms. However, calcium carbonate dissolves naturally in water, so the living organisms are not the only source of it in water. Is ...
4
votes
1answer
344 views

What is this stone?

My Uncle got this stone from Australia and he would like to know what it is exactly The paper is 210 mm on the long side. The stone feels like glass and is softer than metal. On the other side it ...
2
votes
1answer
166 views

Seeking rock identification

This rock was found it Easton, Pennsylvania by the Delaware River. I'm just starting to become interested and collecting and hoping to use this site to gain knowledge on the rocks and minerals I find! ...