The YEC view is that basically the earth is 6-10000 years old. Answers in Genesis list 10 strong evidences for this
here.
These are basically the following
#1 Very Little Sediment on the Seafloor
Problem 1: the current oceans are only (at the oldest) about 175-180 million years old, not billions of years old. That's still more than the 12 million years claimed by by Snelling, but there's no source or calculation provided for that claim.
Problem 2: new seafloor is continuously created at mid-ocean ridges and terrestrial sediment rarely makes it much past the continental slope, so using the average sediment thickness for the entire seafloor is misleading. What matters is thickness on the continental shelf and continental slope.
Problem 3: Snelling discusses the use of a "rescue device" by old-earth advocates of sediment accumulation being slower in the past, but just before that, he uses one of his own by handwaving away his own claim of 12 million years of accumulation with a claim of
faster accumulation in the past in order to shoehorn it into a 6000 year old earth.
Folding occurs at depth, where rocks are subjected to high temperatures and pressures over long periods of time. Under these conditions, it is indeed possible to bend rocks without breaking them. That's not always the case though - we also see brittle deformation in the form of faults, where rocks are bent while too cold or are bent too rapidly and break instead. Soft-sediment deformation - what Snelling claims causes all folding - has specific characteristics that are not seen in most folded rocks. It's also important to note that most folds do exhibit some degree of fracturing and brittle deformation, even if only at the microscopic level.
This has been explained since Snelling's article.
A 25% change in luminosity only results in a 7% change in temperature as explained by the
Stefan-Boltzmann Law, so Faulkner's claim of a 31 degree temperature change is flat out wrong. A 7% change would put the equator at about the same average temperature as the modern arctic. Harsh, but survivable, especially for simple single-celled organisms.
We also have plenty of evidence for several periods of extensive glaciation since then that life has managed to survive, so the sensitivity of life to temperature differences is not really an issue.
The earth's magnetic field switches direction relatively frequently on a geologic timescale. We can observe these changes by measuring the orientation of magnetic minerals within rocks, with a very complete record going back to the opening of the modern ocean basins around 180 million years ago. The last reversal was about 780,000 years ago, so we're sort of due for one. That is likely what we are observing with the current decay of the magnetic field.
I'd suggest reading
this article (written after the article that Snelling claims "addresses all issues") for a good discussion of the issues with this claim. In short:
1. They misidentified the rocks they were studying (which will throw off calculations)
2. They crushed their biotite samples, which can lead to helium loss, and the samples were described as "impure". Biotite diffusion rates (and therefore helium concentrations) are an important part of the models that were used in the study.
3. Measurements from the original Gentry paper were changed with no documentation or explanation other than that they had been "typographical errors."
4. Diffusion modelling requires a precise measurement of the zircon radius, but Humphreys just assumes that it is 30 microns for all samples. No measurements are provided. Similar issues are present with some of his other numbers as well.
Samples can be contaminated through several sources. First, 14C can be a product of decay chains of longer-lived radioactive elements. Second, sulfur bacteria commonly live in coal and will contain atmospheric carbon. Third, modern carbonates and weathering products will contain atmospheric carbon.
This claim also conveniently ignores the fact that carbon dating is pretty solidly corroborated by non-radiometric dating methods such as lake varves, ice cores, and tree rings. A couple of examples of bad data do not invalidate millions of examples of good data.
If there was no source for new comets, we would expect all comets to be the same age. They're not. Not being able to directly observe the Oort Cloud does not preclude its existence as new comets (which exist) have to come from somewhere. Interestingly, creationists also used to make the same arguments about the Kuiper Belt, but that has since been observed and Faulkner seems to have accepted that it can be a source for short-period comets.
A
detailed analysis of sodium in the oceans shows that the input and removal rates are virtually identical, within margin of error. Morton's letter does not (as Snelling claims) ignore the exchange of sodium from seafloor basalts because that is already included in the cited list of input methods.
I'll admit that I don't have a good explanation for this one. However, I'm not a biologist. I do know that bacteria are amazingly hardy and can survive in some pretty extreme conditions. I'm not ruling out the possibility of it being a random modern bacterium either. No need to jump immediately to the conclusion that the Earth is young though as that would ignore a whole host of evidence to the contrary.