地球上的生命每2700万年灭绝一次(但我们离下一个大约有1600万年)

上周在宇宙上也看到了类似的解释。由于地球大约有45.4亿年的历史，这意味着大约有168个不同的灭绝周期。据我所知，地球在极端温度下要么变热要么结冰，然后要么变冷要么变暖，直到水和生命再次成为可能。< / p >

Given that this is correct (and definitely correct if I'm wrong, I'm eager to learn!), what are the chances there was a full civilization like ours that got completely wiped out in a different extinction cycle than ours? Is it possible or are there other factors in the history of our planet that would have prevented life from flourishing to the point that we are in now? I do understand that the factors of creating humans exactly like us are pretty drastically low but I suppose I'm referring to 'civilization' as intelligent life.

And a second part to the question, I know there are fossil records in the different layers of sedimentary rock but would there ever have possibly been an extinction event that ruined the Earth so drastically that it destroyed fossils and rocks (i.e. records of the past)? I've read that the oldest fossil found was 3.5 billion years old but it's not conclusive. Do we have a vast record of fossils and life that is billions of years old?

I have no idea, that's why I just would be interested to have your opinion on this topic. I don't know if it is frequent or rather uncommon to find such "fossils".

Thank you for your help!

我需要地层学中使用的化石信息来为地质学学生做一个智能手机应用程序。< / p >

Can you recommend me a book (in English, French or Spanish) that list main genres, their distribution in Chronostratigraphic Chart, paleogeography and paleoenvironment?

作为一名前生物学家，我发现在著名的侏罗纪海岸寻找化石的经历令人愉快地上瘾。在三天的时间里，我花了大约六个小时收集了大量的菊石碎片。有了这样做的bug，我渴望尝试找到一些更令人印象深刻的标本。< / p >

Chatting to some of the local palaeontologists on the beach it became apparent that to do so you need to split rocks, and that you need to know which rocks to split. It's also clear to me that while I've become attuned to watching for the shapes and patterns indicative of ammonites, I don't yet have the eye for the other colours and shapes of fossil shells and bones.

I tried to do some reading about the geology of the region, but most of what I found online was either too basic (i.e. aimed at non-scientists) or too advanced (i.e. aimed at actual geologists) for me.

So: how can I learn to better spot fossils and fossil bearing rocks in this region? I'd be very interested to learn some geology if it would help, but if that's the case, how can I find material pitched to the right level?

我之前在物理堆栈交换上发布了这个，但它被认为是离题的，这是可以理江南电子竞技平台解的，所以我希望它不会在这里。

最近，我偶然发现了一个叫A.M.的人写的一篇文章

https://web.archive.org/web/20200218162343/http://new.chronologia.org/volume2/turin2.html

这是俄语，所以这里是英语的一些结论，

1. 在放射性碳测年方法中有一个明确未定义的假设——在使用放射性碳测年的整个时间间隔内，大气中¹³C和¹²C的绝对含量是稳定的。这是放射性碳群落的主要秘密。

2. δ ¹⁴C曲线及其导数-放射性碳定年校准曲线反映了¹⁴C在大气中的变化，而不是在CO₂大气中的变化。这是放射性碳社区的主要位置

3. 系统错误是"在校准曲线中:用Libby法定年(它们通过考虑Libby法定年而建立的树木年代表被包括在校准曲线中);使用Delta ¹⁴C图值的错误操作(执行操作是为了“考虑”;人为因素对大气CO₂含量变化的影响);与CO 大气³ C的变化相关。 There are also systemic errors in the estimates of the contribution of the shape of the calibration curve to the dating accuracy. This is the great mystery of the calibration curve.

I am interested in seeing a comment on these claims and maybe on the wider context of the article as well, if possible.

I hope my question is clear enough, thanks.

谁有什么好的推荐?< / p >

Thanks

I'm new here, please tell me if i forgot to mention anything important. Thanks in advance.

Here are some pictures:

Wikipedia mentions stone/iron fossils:

The minerals commonly involved in replacement are calcite, silica, pyrite, and hematite.

Are all minerals involved in "replacement" a stone/iron material, or are other materials ever involved in this process?

Thank you.

It's east of the Wallace line, so 'they got there from Asia' is not an obviously unproblematic conclusion.

In general, when and how mosquitoes reached remote Pacific islands is a nontrivial question. For example, Hawaii was free of them until historically recent time when they stowed away on a ship.

Study finds introduced mosquito species active all year round suggests one particular mosquito species only reached Australia during World War II, but also says

Australia has plenty of 'home grown' mosquitoes

Which indicates that other species have been there much longer.

Did they reach Australia at the same time as the marsupials, tens of millions of years ago when the continent was closer to Asia?

Am I right to understand that permineralization is where the minerals replace the space where the bones of animal (for examples) reside making a cast of what the organism looks like while replacement replaces the bones of that animal on a molecular level where each molecule of the the organism's bones are replacement by a molecule from the mineral i.e. the replacement process is transforming/converting the bones into another substance. Also do the molecules of bones cease to exist after they are replaced?

Thanks for your time.

另一方面，化石往往与特别容易形成化石的地区(如沼泽)有关。沼泽形成于特定的区域，存在的时间有限，并且不均匀地反映了自然历史。如果化石记录的主要限制是化石的零星形成，而不是这些化石的零星发现，那么我们可能永远不会对过渡形式有一个完整的描述。

我们最终能得到大多数“缺失的链接”吗

However, I have not read of diatom shells being used, despite the fact that they were (and are) at least as abundant, correct?

I know that diatoms use silica instead of calcium carbonate... Does that mean anything? Are diatoms using already-ancient sand to make their shells, rather than creating their own from newly-formed molecules, like foraminiferae do? Does that mean any CaCO₃-using creature can be used as an ancient temperature proxy, since they always utilize the oxygen isotopes available in their time and place?

Can diatoms' remains be examined for any ancient information? They are so abundant...

但什么是语素扩张?这是否意味着化石可以比原始生物更大，就像你把大米泡在水里，它会变大一样?< / p >

A < A href="https://www.cnn.com/2021/11/23/us/mammoth-tusk-discovery-at-bottom-of-the-ocean-trnd/index.html" rel="noreferrer">最近公布的一项发现< A href="https://en.wikipedia.org/wiki/Columbian_mammoth" rel="noreferrer">哥伦比亚猛犸象象牙位于加利福尼亚海岸的深水区，这使我想知道10万年前的地质条件是否可以解释它是如何到达被发现的位置的?蒙特雷湾水族馆研究所(MBARI)的研究人员、飞行员兰迪·普里克特(Randy Prickett)和科学家史蒂文·哈多克(Steven Haddock)在2019年在离岸185英里、海洋深处1万英尺的地方发现了一根哥伦比亚猛犸象象牙，该机构在一份新闻稿中说。< / p >

According to the Monterey Bay Aquarium Research Institute, the tusk portion is at least 100,000 years old:

The team believes it could be the oldest well-preserved mammoth tusk recovered from this region of North America. Dating of the tusk is being done by the UCSC Geochronology Lab led by Terrence Blackburn, associate professor of Earth and planetary sciences. Blackburn analyzed radioisotopes to show that the tusk is much more than 100,000 years old. “Our age estimate on the tusk is largely based on the natural radioactive decay of certain uranium and thorium isotopes imparted to the tusk from the ocean. If the tusk had been found on land, deciphering its history would not be as straightforward,” said Blackburn. Christopher Edwards and Patrick Drake will examine the oceanographic currents to better pinpoint where the tusk originally came from.

Another article I looked at mentioned they were exploring an underwater seamount formation with the ROV, so it looks like the approximate location might be about here:

This looks well beyond any continental shelf or continuous undersea canyon type formations which might connect the location to the shoreline.

So, is there a geological explanation for how this mammoth tusk might have ended up at this location?

我的女儿在德国南部的斯瓦比亚Jura< a href="https://en.wikipedia.org/wiki/Swabian_Jura" rel="nofollow noreferrer">时发现了这个化石。< / p >

She asked me about it, but I have absolutely 0 clue about geology. The crystal part is 3cm in diameter, but there's a brighter region around it, which might also belong to the fossil, and is 6.5cm in diameter.

Is it an ammonite? How old could it be? Is it really some kind of crystal, is it some salt?

I'd be happy to give my daughter any info. All I've got until now is "That's a beautiful fossil".

Here are some more details:

Does this also belong to the fossil?

Because of the density of the bone I frequently find talus bones as a walking safari guide in Kenya. I could therefore understand if this bone is over represented in the fossil record.

I suppose also though that this is a difficult question to answer since there may not be any analysis of this kind within the scientific literature. At least, I have found none.

Here are below a few Talus bones I have found:

不包括临时事件，如大规模灭绝

根据Ravindra Kumar的Historical Geology and Stratigraphy >，元古代早期的生命形式由于缺乏坚硬的部分，不能作为化石保存下来。除此之外，< strong>Kumar还指出，

随着硫、硫化氢、二氧化碳等有毒物质的去除，元古代沉积盆地中藻类等生命形式蓬勃发展。

我已经多次尝试寻找任何可能的答案，但无法找到任何令人满意的。如果有人对这个问题有想法，请试着回答。

提前感谢。

[1]: https://i.stack.imgur.com/ye4XU.jpg

文章地球磁场影响了我们的进化吗? on Pledge Times引用这篇科学论文断言: