![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
I've removed the Nanocycles method addition. It isn't a recognised 'dating method' as described in the article. It could be considered a type of incremental dating technique, but these are usually based on periodic addition of material through a continuous or correlated sequence(s). However, it would be fair to add something about variations in lunar cyclicity and the age of deposits, but this isn't usually referred to as the Nanocycles method. See Talk:Nanocycles method. Any ideas? NickW 09:04, 25 May 2005 (UTC)
Removed ref to Th-Pb dating. To the best of my knowledge Th-Pb is always done in conjunction with, and subordinately to, U-Pb dting and is very unlikely to every require an article of it's own. Unless I'm wrong, of course. Feel free to change back if so. Cheers, Rickert 04:12, 10 February 2006 (UTC)
The subject matter in this article that deals with radiometric decay is reproduced in radiometric dating and can be merged. The downside is that merging with radiometric dating would leave dendro, varves, ice cores and lichenometry out in the cold. This article, however, doesn't really do them justice and really just provides a list of links. Any thoughts? Rickert 05:11, 10 February 2006 (UTC)
Geochronological units - examples:
You can write: Tyrannosaurus rex lived in Late Cretaceous, but if you write: a T-rex was found in Late Cretaceous, you mean that a timetraveller found it 67 mya.
See also Chronostratigraphy.
This text is inaccurate and irrelevant. Firstly, the name of eons and aeons, etc are derived by reference to the classical bostratigraphic nomenclature. For instance, the Proterozoic is the age before multi-cellular animals. The Palaeozoic s the bit before vertebrates; etc etc. These divisions n time were derived before the 'ages of which they relate to were known; biostratigraphy (when done well) is absolute in that a faunal assemblage places it in the correct Period, but has no absolute age information.
Hence, deriving an age date from radiometric dating or other geochonological method does nothing to give a rock a biostratigraphic age; in fact in the case of some age date information, it relates more to a geologic event (metamorphic event, etc) than to any real rock stratum or igneous event. Hence, it is not sufficient nor accurate to start quoting "geochrnological units" and subdivisions.
We must gain an age date number from the process and methods of geochronology; radiometric dating. We then assign this significance based on an interpretation of what the data means. For instance if we derive a Rb-Sr isochron of a granite, the isotopic data doesn't lie; that is the Rb-Sr composition of the granite when it cooled below the closure temperature. But we have to say whether it is the age of emplacement, metamorphism, etc.
We can then relate this to any biostratigraphic information only when it crosscuts and when the age of the biostratigraphy is known. This is an inference, not a fact, and hence, it is imporoper to say a granite is Dalradian, for example. We must give geochronological dates in ka, Ma, Ga.
A case in point is the Permo-Triassic boundary. This is a date unfixed in time because of a laack of conclusive cutting of the floral and faunal successions by a known igneous rock. We know it is around 250 Ma, and there are plenty of rocks of around that age, but the age date changes a few Ma each way each time a new age date is given and rigorously proven to define and bracket the fossil assemblages of the Permian and Triassic.
If, for argument's sakes, you called a granite Permian, and the biostratigraphic column's chronostratigraphy was altered, it could then in hndsight be shown to be Triassic if the goalposts are moved. Hence, i reisterate, do not confuse biostrat with chronostrat, with geochron.
Cheers, Rolinator 07:05, 30 October 2006 (UTC)
I can't for the life of me figure out what this example means or why it's here. Could someone clarify it or delete it if it serves no purpose? —Preceding unsigned comment added by 74.12.71.34 ( talk) 02:30, 28 January 2008 (UTC)
In reading the article, I see that the unit of measure "Ma" as in "270.6 +/- 0.7 Ma" is undefined. Since I am not a student of geochronology, I have no idea what it means. From the context, I can only presume it to be a date equivalent to a Before Christ year (BC). Further research caused me to find, in another article, the explanation "(Ma = millions of years ago)". Since it is not a common abbreviation, I would suggest including the definition with the first instance of its usage in every article in which it is used.
I made the insert in this article, but I do not have the means or time to discover other unexplained instances if its usage. James thirteen ( talk) 13:43, 1 September 2008 (UTC)
Ma is Million annum (short for million earth years). Ma may have been used in geologic past tense context article, thus shortened from ""Ma ago"" to Ma. Morbas ( talk) 12:18, 27 June 2010 (UTC)
It would be a reasonable idea to have a section on sources of error in geochronology, but the section I just reverted dealt with errors in how people talk about geological time, and tried to illustrate differences between geochronology and chronostratigraphy. I don't think it even did that well (see my comment here. The reverted text is confusing and unhelpful: it does the article no good to leave it there until someone takes the time to wrote up a proper text on the differences between geochronology and chronostratigraphy. I mean, honestly, it is not a source of error in geochronology that someone could make an ambiguous statement that some very fanciful person could think meant he'd been in a time machine to the late Cretaceous. Babakathy ( talk) 18:56, 24 October 2008 (UTC)
Would it be possible for someone to add to this article a table summarising the applicable age range, error limits and materials that each method can be applied to. At the moment this information is distributed across all the sub-articles and therefore time consuming to find. 81.154.116.170 ( talk) 17:44, 28 July 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Geochronology. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 23:46, 12 October 2017 (UTC)
Does relative dating fall under Geochronology? -- Harizotoh9 ( talk) 17:38, 29 September 2012 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
I've removed the Nanocycles method addition. It isn't a recognised 'dating method' as described in the article. It could be considered a type of incremental dating technique, but these are usually based on periodic addition of material through a continuous or correlated sequence(s). However, it would be fair to add something about variations in lunar cyclicity and the age of deposits, but this isn't usually referred to as the Nanocycles method. See Talk:Nanocycles method. Any ideas? NickW 09:04, 25 May 2005 (UTC)
Removed ref to Th-Pb dating. To the best of my knowledge Th-Pb is always done in conjunction with, and subordinately to, U-Pb dting and is very unlikely to every require an article of it's own. Unless I'm wrong, of course. Feel free to change back if so. Cheers, Rickert 04:12, 10 February 2006 (UTC)
The subject matter in this article that deals with radiometric decay is reproduced in radiometric dating and can be merged. The downside is that merging with radiometric dating would leave dendro, varves, ice cores and lichenometry out in the cold. This article, however, doesn't really do them justice and really just provides a list of links. Any thoughts? Rickert 05:11, 10 February 2006 (UTC)
Geochronological units - examples:
You can write: Tyrannosaurus rex lived in Late Cretaceous, but if you write: a T-rex was found in Late Cretaceous, you mean that a timetraveller found it 67 mya.
See also Chronostratigraphy.
This text is inaccurate and irrelevant. Firstly, the name of eons and aeons, etc are derived by reference to the classical bostratigraphic nomenclature. For instance, the Proterozoic is the age before multi-cellular animals. The Palaeozoic s the bit before vertebrates; etc etc. These divisions n time were derived before the 'ages of which they relate to were known; biostratigraphy (when done well) is absolute in that a faunal assemblage places it in the correct Period, but has no absolute age information.
Hence, deriving an age date from radiometric dating or other geochonological method does nothing to give a rock a biostratigraphic age; in fact in the case of some age date information, it relates more to a geologic event (metamorphic event, etc) than to any real rock stratum or igneous event. Hence, it is not sufficient nor accurate to start quoting "geochrnological units" and subdivisions.
We must gain an age date number from the process and methods of geochronology; radiometric dating. We then assign this significance based on an interpretation of what the data means. For instance if we derive a Rb-Sr isochron of a granite, the isotopic data doesn't lie; that is the Rb-Sr composition of the granite when it cooled below the closure temperature. But we have to say whether it is the age of emplacement, metamorphism, etc.
We can then relate this to any biostratigraphic information only when it crosscuts and when the age of the biostratigraphy is known. This is an inference, not a fact, and hence, it is imporoper to say a granite is Dalradian, for example. We must give geochronological dates in ka, Ma, Ga.
A case in point is the Permo-Triassic boundary. This is a date unfixed in time because of a laack of conclusive cutting of the floral and faunal successions by a known igneous rock. We know it is around 250 Ma, and there are plenty of rocks of around that age, but the age date changes a few Ma each way each time a new age date is given and rigorously proven to define and bracket the fossil assemblages of the Permian and Triassic.
If, for argument's sakes, you called a granite Permian, and the biostratigraphic column's chronostratigraphy was altered, it could then in hndsight be shown to be Triassic if the goalposts are moved. Hence, i reisterate, do not confuse biostrat with chronostrat, with geochron.
Cheers, Rolinator 07:05, 30 October 2006 (UTC)
I can't for the life of me figure out what this example means or why it's here. Could someone clarify it or delete it if it serves no purpose? —Preceding unsigned comment added by 74.12.71.34 ( talk) 02:30, 28 January 2008 (UTC)
In reading the article, I see that the unit of measure "Ma" as in "270.6 +/- 0.7 Ma" is undefined. Since I am not a student of geochronology, I have no idea what it means. From the context, I can only presume it to be a date equivalent to a Before Christ year (BC). Further research caused me to find, in another article, the explanation "(Ma = millions of years ago)". Since it is not a common abbreviation, I would suggest including the definition with the first instance of its usage in every article in which it is used.
I made the insert in this article, but I do not have the means or time to discover other unexplained instances if its usage. James thirteen ( talk) 13:43, 1 September 2008 (UTC)
Ma is Million annum (short for million earth years). Ma may have been used in geologic past tense context article, thus shortened from ""Ma ago"" to Ma. Morbas ( talk) 12:18, 27 June 2010 (UTC)
It would be a reasonable idea to have a section on sources of error in geochronology, but the section I just reverted dealt with errors in how people talk about geological time, and tried to illustrate differences between geochronology and chronostratigraphy. I don't think it even did that well (see my comment here. The reverted text is confusing and unhelpful: it does the article no good to leave it there until someone takes the time to wrote up a proper text on the differences between geochronology and chronostratigraphy. I mean, honestly, it is not a source of error in geochronology that someone could make an ambiguous statement that some very fanciful person could think meant he'd been in a time machine to the late Cretaceous. Babakathy ( talk) 18:56, 24 October 2008 (UTC)
Would it be possible for someone to add to this article a table summarising the applicable age range, error limits and materials that each method can be applied to. At the moment this information is distributed across all the sub-articles and therefore time consuming to find. 81.154.116.170 ( talk) 17:44, 28 July 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Geochronology. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 23:46, 12 October 2017 (UTC)
Does relative dating fall under Geochronology? -- Harizotoh9 ( talk) 17:38, 29 September 2012 (UTC)