/sci/ - Science & Math

Radiocarbon dating. But this is a troll thread, so whatever

>>8580536
You do know, spasoid, that you should only use radiocarbon dating on things that were once alive, right?

Otherwise, what you're saying is akin to:
>This hammer isn't very good at painting walls, I guess this hammer is a useless tool.
Sadly, the only useless tool is you and your creationist compatriots.

>>8580600
How do you date the rocks that have no fossils then? Comparing layers?

>>8580603
Not a geologist, but I think so?

sage and move on, this guy isn't interested in a real discussion.

>>8580559
*radiometric dating
14C is only good going back ~60kya, and usually requires organic material.

>>8580603
more or less. you look for correlative features (flooding surfaces within a basin, ash beds, etc.) and use them to align outcrops/well logs/cores.
this only goes for sedimentary units, naturally. igneous deposits can usually be radio dated (since the rocks and the crystals within them formed at the same time), or (if volcanic) at least constrained by under/overlying layers. with metamorphic rocks, sometimes you can use one of those, sometimes ur fuckt

>>8580616
>igneous deposits can usually be radio dated (since the rocks and the crystals within them formed at the same time)
Could you please explain this a little more detailed, kind anon? How does "igneousing" depend on date? Sorry for retarded asking

>mantle material rises
>melts through decompression
>melt intrudes into crust and slowly cools
>crystals precipitate out of melt
>as melt cools, rock is formed from all the mineral crystals

some minerals have qualities that allow you to determine how long ago the crystals formed. to use a famous example, zircons may incorporate uranium into their structure, but don't incorporate lead. so any lead found in a zircon must have originally been taken up as uranium and later decayed. by comparing the levels of uranium and lead in a zircon, one can determine what fraction of the uranium has decayed and (knowing the half-life of uranium) therefore how much time has passed since crystallization. (it helps that there are two separate decay series, starting with 235U and 238 U, that can be checked against each other.) this is how we know the Earth is ~4.54 Gy old.

why it matters that a rock is igneous is that radiometric dating only tells you how long ago the crystal formed. if you find a zircon in a sandstone, for example, the crystal is likely much older than the rock it's in. (that is, it crystallized, was eroded out, and later was incorporated into a sandstone.) the crystals in igneous rocks, on the other hand, almost certainly formed in situ and haven't been reworked or transported.

does that make sense?

>>8580738
Awesome thanks.

>having to fight all fields of science simultaneously to keep your pet scriptural theory afloat

>>8580616
How about uranium/lead dating?
How about potassium/argon dating?
Stop me if you run out of room for your goalposts.

wrong reply address

>>8581005
>t-rex evolved into a chicken
Stopped reading there

>>8581005
>no evidence of reducing atmosphere
yeah, it's pure coincidence that we find detrital pyrite and uranite before ~2.2-2.0 Gya and not afterwards.

>>8580677
I'm not the anon you asked, but i do have an explanation for you.

when a rock is cooled from lava or perhaps magma to form a black glass-like structure, we call it an igneous rock. when suck a rock solidifies, it will have a certain amount of material which is radio-active. this initial proportion of radio-active material is the same for the majority of rocks of this types. as tonne goes on, the radio-activity decays away. measuring the current radio-activity and comparing to average initial radio-activity gives a good estimate for when the rock formed.

many rocks have some sort of dating system which allows geologists to figure out when the rock was formed from deposited dust or lava etc. this is the method we use to give how old a rock is.

a fossil is dated based on the age of the rocks it is embedded in. thus, fossil age approximate, but still accurate enough to build scientific theories

>>8581115
this is subtly wrong from top to bottom and I really just hope you're trolling.