19

Bones don't last very long in jungles. Or in forests. Or almost anywhere. Fossils are the consequence of one highly unlikely fluke after another. Darwin himself commented on this. It takes just-right circumstances to have the bones of a recently deceased animal not be eaten by scavengers or turned into rot by bacteria. It takes yet another set of just-right ...


15

The idea of mass extinction is not that recent actually: Cuvier (1798), Buckland (1823) and d'Orbigny (1851) for instance were already talking about global catastrophes in earth history, linked to extinctions. But during the same period, Brocchi (1814) and Lyell (1832) proposed that extinctions of species occurred individually and were a gradual process (...


15

Because you find fossils by looking at exposed bedrock, deserts by their nature often have huge expanses of exposed bedrock. The lack of plants is also a big benefit, plant roots tend to destroy fossils Fossils are everywhere you have sedimentary rock* deserts are actually rather poor at forming fossils compared to many other environments. They are FOUND ...


15

thank you for your interest in the article. I'm the lead author on this paper (Shipway) and I happened to come across your post when looking through all the media stories on this animal. To answer your question; yes, you're right, the rock is a calcareous sandstone. It was easy to split, partly because it is a naturally soft rock and partly because the ...


14

Basically, we know they were likely pelagic creatures because we find their fossils at essentially all water depths. If they were benthic creatures, we'd expect their fossils to be limited to a set range of paleo water depths. It's unlikely that a single benthic (i.e. living on the seabed) marine organism could live in both shallow water and ultra-deep ...


14

The biggest temporal gap would be (IMO) the Precambrian, specifically pre-Ediacarian. Accordingly the biggest gap in the evolutionary history is the origin of eukaryots, both because of the paucity of pre-Ediacarian formations but also because few of the early protists were likely to be fossilizable. From the probable apparition of life ca. 3.8-3.5 Ga (e. ...


13

To answer your question to the point: we don't know at all. For most of living organisms, the fossil record is either inexistent or very fragmentary. Even estimating the number of species (which is somewhat less difficult since you need only one specimen of each species to have access to that information) is very difficult and affected by many, many ...


12

Organic material (plants and animals) contains carbon. Carbon has three main isotopes: carbon 12, 13 and 14. Carbon 14 is radioactive, with a half life of 5730 years. Carbon 14 is continuously created in the atmosphere by cosmic rays hitting nitrogen. The nitrogen atoms lose a proton when struck by cosmic rays, turning the affected nitrogen atom into an ...


11

How do archaeologists address time dilation when analyzing carbon dating results? They don't. There is NO point in doing so. Compare two hypothetical substances at the peak of Chimborazo (the highest peak in the world with respect to distance from the center of the Earth). Suppose one of those substances spent all of the last 4.5 billion years at several ...


11

Organic-walled microfossils (wether they be dinoflagellates, pollens, spores or "acritarchs") all have in common to contain an organic compound known as sporopollenin (for the spores and pollens) or dinosporin (for dinoflagellates and, I believe, acritarchs as well). Both compounds have chemical and structural similarities but have appeared independently. ...


11

For all intents and purposes, the Earth represents one frame of reference, as @kwinkunks states. Therefore no effect. Yes the gravitational field on top of a mountain is slightly less than at sea level. This is very small though. Variations in gravity over the Earth's surface typically vary at most by a few hundred milligals (ie. "one part in 10,000" order ...


11

Some authors thinks that the extinction of the Pleistocene megafauna (large mammals such as mammoths, etc.) was contemporaneous with the Younger Dryas (Firestone et al. 2007; Faith & Surovell 2009), while some thinks that it predates it by a couple thousand years (Gill et al. 2009). Whether or not it was contemporaneous with the Younger Dryas, it ...


10

You particularly mention black shale: the reason it's important is that shale is composed of mud- and silt-sized particles, so to form requires an environment with very slow-moving water such that the particles can effectively sediment out - and such that larger clastic material has already been deposited. The higher the water flow rates, the larger the ...


10

Though I agree with @kaberett that there is indeed more and more evidences that the Deccan volcanism was the main trigger of the K/Pg crisis, i wanted to add that there is a more nuanced hypothesis (that I heard about last week during a talk at EGU) according to which the Chicxulub impact resulting seismic response may be the trigger of one of the main stage ...


10

No, it did not definitively single-handedly cause the KT mass extinction event. Around the same time, the Deccan Traps Large Igneous Province (India) was being emplaced. Flood volcanism has been associated with other mass extinctions, due to the impact on climate, sunlight at the surface, etc, of the output of huge volumes of sulphur-based gases. The ...


10

I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication ...


9

Keep in mind that although I am a paleontologist, I am not a vertebrate paleontologist so I might not be aware of every single find ever made of feathered dinosaur. As far as I can tell, all dinosaurs fossils exhibiting feathers belong to the Theropoda. Here is a (probably dated) phylogeny of dinosaurs from Sereno 1999: Credit: Paul C. Sereno Theropoda ...


9

The most common explanation for microbial activity in serpentinites is the exploitation of abiogentic hydrogen and methane formed during the serpentinisation process. Quoting the abstract of a recent authoritative review: The process of serpentinization creates strongly reducing conditions and produces fluids that are highly enriched in molecular ...


9

The oldest undisputed fossil are Stromatolites, bacterial mats, the oldest of which are dated ay 3.7 billion years ago. The key term here is undisputed, there are other possible fossils but it is very hard to have certainty with chemical or cellular fossils. The oldest uncertain fossils trace back to 4.28 billion years and are possible bacteria trapped in ...


8

An important branch of experimental palaeontology is studying the effects of natural processes on plant and animal remains. With that in mind, I would suggest trying to replicate the results of the 2013 (ig) nobel prize winners in archeology. Not only will you be testing a scientific hypothesis, you will be testing whether or not your daughter has what it ...


8

Palaeontologists use lots of methods to investigate past life. Like most sciences these day, palaeontology is a growing field. More scientists are applying more methods in more sophisticated ways. The literature — what we 'know' — grows and grows. So palaeontologists use hundreds of different methods and tools today; indeed there's a whole journal ...


8

There are definitely many examples of overlying Mesozoic strata that contain characteristic dinosaur fossils (and ichnofossils – i.e. trace fossils). One of the best examples is the Mesozoic stratigraphy of Utah and Colorado. However, most geologic intervals are characterised by less ‘famous’ fossil material (e.g. molluscs, trilobites or pollen grains). This ...


8

To complement @MarkRovetta answer, McLoughlin & Grosch reported this year during EGU findings of carbonaceous fragments that they think are biogenic in the 3.4 Ga Buck Reef Chert. Chemical tests are still ongoing however. Schopf (2006) in his review of archean life reported a dozen of fossils in the 3 to 3.5Ga range. They are all "putative" fossil, ...


8

Fossils are our strongest, and to most people most accessible, evidence of the great age of life on earth. The fossils in the Burgess Shale are clearly the imprints of critters, but are a mere 505 million years old. The oldest cyanobacteria-like fossils known are nearly 3.5 billion years old, among the oldest fossils currently known. There is Evidence for ...


8

Your analogy with burying a box is not as accurate as you think. It needs specific sedimentary conditions for the remains of an organism to fossilize: being buried in soil is far from enough. Fossilization is such that, eventually, the fossil will be embedded in its stratum, meaning that tectonic events (as you suggest) that would displace the fossil will ...


8

The ‘Oligo-Miocene’ part The Oligocene and the Miocene are epochs of geological time. The Oligocene lasted from ~33.9 million years ago to ~23 million years ago; the Miocene followed immediately after the Oligocene, and lasted until ~5 million years ago. Oligo-Miocene refers to events that happened around the boundary between the two epochs at ~23 million ...


7

Also please note the important difference between Gravity waves which come from hydrodynamics, and which you apparently refer to, when saying "gravitational waves ripple across the face of this planet every day". This is ofc not true, as the waves that contribute to energy transport in the atmosphere are not the gravitational waves from general relativity. ...


7

You need to be very wary of anything written in the non-scientific media about science. The media loves woo and controversy because those are the things that garners readers, and that in turn garners advertising revenue. By way of analogy, suppose as near-adult in gym class someone said "My gym shoes smell bad. Bad! Awfully bad!" Someone else would ...


7

Earth travels along its orbit at about 30km/s. If you plug that number into a time dilation calculator, you'll find that one second on Earth passes every 1.0000000050069 seconds in a Sun-centric reference frame. Carbon-14 dating is good only to about 40,000 years into the past; Earth's time dilation would reduce that 40,000 years by a little under two hours,...


7

First, let me link a variety of popular science articles which can give you some background explanation. Here are Scientific American, Smithsonian, and Audubon magazines. The 'smoking gun' evidence linking birds and dinosaurs is the evolution of feathers. Feathers are a feature that set the birds apart morphologically from the rest of the tetrapods, and ...


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