2006-10-05 17:12:36 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
It's Carbon-14, Carbon is available in fossils in plenty amount, the ratio of "decayed"carbon to "normal" carbon varies as per time elapsed, It's because of half life of radioactive carbon.
2006-10-05 17:25:53 · answer #1 · answered by Anonymous · 0⤊ 1⤋
U-238 has a a million/2-existence of four.40 six billion years. i do no longer understand if that's used that seems to long. I-131 has a a million/2 existence of 8 days, so it may well be notably ineffective for geological dating. C-60 isn't modern-day in nature it rather is a lab produced isotope. T-ninety 9 has a a million/2 existence of 211.000 years. i think of it relies upon on how a procedures returned your attempting to degree. if your finding for Genesis rocks from whilst the Earth became first formed then i'd say the U-238. yet whilst your measuring something extra modern-day like the final Ice Age then consistent with probability T-ninety 9.
2016-12-26 10:55:28 · answer #2 · answered by ? 3 · 0⤊ 0⤋
Usually thorium - 234, IIRC (created from alpha-emission of 238 U, I seem to recall). For magmatic or mildly metamorphic rocks with an assumed known starting concentration of 238 U an age can be calculated.
14C or radiocarbon cannot be used for anything older than a couple of 10000 years. Fine for archaeological finds, past its limits for anything older than the last ice age.
Sediments usually are dated using magnetic information.
Marine sediments with benthic foraminifer fossils may get additional dating from (non-radioactive) C and O isotope ratio, which depends on the temperature at the liftime of the organism, which then can be compared to temperature curves from other sediments (both marine and ice).
2006-10-05 22:31:27 · answer #3 · answered by jorganos 6 · 1⤊ 0⤋
Carbon 14 is used to date fossils (formerly living things), but for dating rocks and minerals which were never alive, potassium/ argon and the breakdown of uranium (thorium, radium, etc.) are used.
2006-10-05 17:29:11 · answer #4 · answered by cdf-rom 7 · 0⤊ 0⤋
carbon-14
2006-10-05 17:14:12 · answer #5 · answered by buccinator 3 · 1⤊ 0⤋
Am sure it carrbon 14 go to wikipedia .com
2006-10-05 17:46:53 · answer #6 · answered by secret &trade 4 · 0⤊ 1⤋
i believe its carbon-14
2006-10-05 17:20:04 · answer #7 · answered by ynroh 3 · 0⤊ 1⤋