The Blue Amber Blog

Have you seen this movie about DNA in amber that could recreate Dinosaurs, so they could break loose and feast on skeptics? You may have heard of it. No way to measure the age of DNA?

Indeed there is. It’s called Amino Acid Racemization (AAR) and it’s not as bad as it sounds.

As stated previously, there is a good chance that proteins can still be found in amber bugs.

Amino acids are in a certain orientation while part of a living organism (right-handed, they call it) and will flip over when the organism is dead (to the left-hand orientation).

Except nobody really calls it ‘flipping.’ The proper term is ‘racemization’, although I think ‘flipping’ is cooler, so let’s stick with it.

This flipping takes time and it’s the ratio from flipped to unflipped that can give an indication of the age.

Generally AAR-ing can measure around 500 million years into the past and stay fairly accurate, but it does get a bit tricky with amber.

More recent studies show that chances to find amino acids (and ergo DNA) that survived unharmed inside amber are Slim to None.

And Slim just left town.

Citations:

Proc R Soc Lond B Biol Sci 1997 Apr 22;264(1381):467-74

Amino acid racemization and the preservation of ancient DNA.

Austin JJ, Ross AJ, Smith AB, Fortey RA, Thomas RH.

Department of Palaeontology, Natural History Museum, London, UK. Abstract
Apparently ancient DNA has been reported from amber-preserved insects many millions of years old. Rigorous attempts to reproduce these DNA sequences from amber- and copal-preserved bees and flies have failed to detect any authentic ancient insect DNA. Lack of reproducibility suggests that DNA does not survive over millions of years even in amber, the most promising of fossil environments.

Bugs, feathers, plants and lizards.

Plenty of them doing time in amber.

Obviously they can fit into a respective evolutionary pattern, which then should correlate to a certain time period in the long history of earthly evolution.

Except they don’t.

Trying to fit amber inclusions into the evolutionary pattern has become a game of hammering the peg into the preconceived hole: sometimes they fit just perfectly, sometimes they don’t, sometimes we have to cheat. And sometimes the peg is square and the hole is round and you have to hit hard to make it fit.

Really hard.

As an example serves our good friend, the anole, a.k.a. gecko, a.k.a. lizard, a.k.a. That Little Green Thing That Just Crawled Over My Foot.

You can’t go to a Caribbean island without coming across one of these adorable tiny lizards, and when amber was still a sticky goo dripping from the trees, they were already out and about.

It is interesting, if unnerving, to note that the million-year old anoles found in amber seem to stem from the same family as the ones alive today – as if the lizard in the amber was enclosed just last year.

This sort of takes all the fun out of evolution because it would mean that anoles did not evolve at all over the past 30 to 15 million years, while in the same time-frame humans managed to climb down from the trees, shed fur, walk upright, use tools, invent wars, Hotdogs, New York and the Super Bowl. Apparently anoles just sat around and watched.

Let’s do some hammering. The most logical explanation we have for this discrepancy is that evolution works in intervals – short bursts of evolving that last a few million years or less and then nothing for a few epochs. Once the burst is over the species establishes itself and sticks around for a while without changing. Further evolving may be possible after that, but it hasn’t happened yet.

The other explanation is shorter, and some people start rolling their eyeballs when you bring it up — you know what I mean.

There’s a law, and it’s the Law of Superposition.

It basically states that the deeper a deposit, the older it is, the shallower the deposit the younger it is.

It’s a great way to date rocks and its logic as heck.

It’s a law and geologists get very grumpy when someone dares to speak against it.

But then there is the issue of redeposition.

The reason why Dominican amber is often found in different strata may be because it moves around a lot.

Ergo, this could mean that amber did not become amber in its current location, but got moved there a long time ago, which could mean it is even older than we think.

Numbers proposed range anywhere in between the Cretaceous (Brouwer and Brouwer, 1982) to pre-Lower Miocene period (Baroni-Urbani and Saunders, 1982) — meaning about 100 million years ago and less (the approximate time of the dinosaurs, which should make Jurassic Park fans very happy).

This theory is often refuted because little amber, if any, is ever found in rock formations known to be from the Mesozoic Era (it has been found, but not enough to validate an argument).

Still, redeposition is not out of the question and needs further examination.

It doesn’t exactly break the Law of Superposition, but it doesn’t support it either.

Just makes it all fuzzy.

You know, sometimes I get the impression Momma Earth does this on purpose to make things hard on us.

Dating amber alone is risky – always bring a chaperon.

In this case the strata and rocks in which amber is found.

Anyone familiar with the previous newsletter will remember that amber was deposited in dirt and sand at the bottom of lagoons as copal.

Hence this dirt and sand is organic rich and contains forms of microfossils – fish teeth, oysters, corals, mollusks, tiny crustaceans – that can help in verifying the age.

And it is thanks to much of these microfossils that we say 20 million years, the Early Miocene period, independent from the amber.

And, yes, you guessed it: there is yet another problem.

The dirt in which amber is found differs from site to site all over the island.

Generally we are dealing with clastic sedimentary rocks composed largely of quartz with other common minerals including feldspars, amphiboles, clay minerals, and sometimes more exotic igneous and metamorphic minerals such as slate, schist or gneiss.

But exactly that causes difficulties because sometimes there aren’t any or not enough microfossils to go by and the different rocks and minerals are from time periods older or younger than previously assumed.

That makes correct dating a real stumper.

Schist happens.

When atoms are irritated with external magnetic fields, their own magnetic fields go hinky; much like when you hold a magnet next to a compass.

They begin to resonate at varying frequencies and all sorts of valuable information can then be extracted, just like in a classical good cop/bad cop interrogation.

Even an estimate on age.

It’s called Nuclear Magnetic Resonance (NMR), and once again a few very smart fellows got the Nobel Price for it.

In biochemistry the application works great to study the structure of biopolymers – molecules consistent of chain-gangs of even smaller molecules called monomers.

Some of the better known biopolymers are proteins, starch and DNA, just to give you an idea.

Since amber is an organic material, its gang-chain structures (particularly the exomethylene gang) can be studied and measured through NMRS.

And yes, another Nobel went out for that doozy.

So, let’s run a test, shall we?

Amber from mines in the La Toca and Tamboril area on the north of the island are pegged at being about 40 million years of age (Lambert et al., 1985).

On the other hand, the resonance signature of the biopolymers in amber from the Bayaguana and Cotui area in the east of the island indicated an age of being around 15 million (Van den Bold, 1988).

Oops.

Here’s the problem:

In order to be able to evaluate the resonance signature of amber, one has to compare it to the resonance signature of a sample were the age is known, as well as an actual resin sample straight from a tree and still sticky.

But how can we know the exact age of the second amber sample?

Also, since the original trees are extinct, the resin used is from a family member only.

Differences may occur as seen in the above test.

The technique in general is promising, but still needs finagling.

A definite classification system by which to interpret the resonance images is still in the works and future results may shed some more light.

But for now we are working with flashlights in a dark room, so to speak.

It may sound like a dangerous form of courtship, but far from it.

Every living thing continuously exchanges carbon dioxide through food and air, going in and out.

But once the living thing dies, no more carbon going in — only out.

By literally counting how much carbon atoms (more precisely an unstable carbon isotopes known as carbon-14, but who’s being picky) decays, a time frame can be estimated.

Willard Frank Libby got a Nobel Price for figuring that out.

Sounds great?

So does sliced bread, but nobody got a Nobel for that one.

The problems with this technique is that results are often corrupt, bringing up uncomfortable questions: time and the environment influence the decaying speed, solar flairs may change the amount of carbon in the atmosphere, etc, ad infinitum.

Britain’s Science and Engineering Research Council once sent out a sample of a known age to 38 labs, and only seven returned “satisfactory” results.

Fortunately amber has a decaying process not overly influenced by heat or humidity. This should reduce the error margin when dating amber the Radiocarbon way.

But geologists are well aware of the final and most striking problem with using C14 Radiocarbon Dating: the measurable age limit is in the range of 60,000 years, when any measurable carbon as fled the dead object.

Obviously, amber doesn’t make the cut.

So what gives?

It seems that Mother Earth is like most women: often moody, mostly incomprehensible and she doesn’t like to admit her age.

Well, okay, I don’t know about most women, but it certainly applies to Momma Earth.

In fact she hates it so much, she endlessly undergoes surgery to remove any possible hints of age, what with her shifting, reforming and changing crust all the time.

The oldest rock we were lucky enough to find, a tough little zircon crystal picked up in Australia, was measured at 4.4 billion years according to its uranium decay.

So if she doesn’t want to give out her age, what do nosy scientists do?

They ask her little daughter, the moon.

After all, Luna is literally a chip off the old block, having broken away in a collision with the hypothetical planet Theia – an event aptly known as the Big Whack.

Or so the most recent theories say.

Moon samples brought back by the Apollo missions say earth may be 4 billion years old, as close as we can peg it.

But geologists swear not by the moon, the inconstant moon.

Other sources are also questioned of course, such as the highly independent meteorites. Nothing is left out.

The 12-zero-figures determined of all three sample elements correlate somewhat, putting Momma Earth’s age at somewhere between 4 and 5 billion.

More or less.

Approximately.

Sort of.

But that is just the technicality we are trying to dig up: the difference between 4 billion and 5 billion for example is, well, 1 billion.

As Ted Turner put it, that’s “a nice round number.”

Isn’t that a bit much to be vague about?

Well, compared to the age of the rest of the universe, it’s a fairly small error margin. We’re still learning, and Momma Earth is no easy lady to deal with.

Still, with these margins, don’t ever lend a geologist money — they consider a million years to be recent.

Geologists are Amazing

They know hundreds of words for different sorts of dirt and hundreds of words for things it does when left alone for a few million eons. And geologists and Ted Turner have one thing in common: they love to toss those millions around as if they were pennies.

Well, they have to. By the 1800s “Uhm” and “cough-cough” and “it’s a mystery” and “6,000” no longer sounded plausible as answers to the age of the world. So geologists began throwing out numbers so preposterously large, they just had to be correct. And since then rock hunters have figured that millions are so very cool and have adapted their own finds and theories to fit that time frame.

But how old is Dominican amber, really? Can we take the geological numbers for granite? Where do these preposterous numbers even come from?

Do we even know its age?

If someone wishes to push the point, then no we don’t, not for certain. It’s all Guessing.

But in all fairness, it’s very Educated Guessing.

There’s a difference.

So how old is amber really?

Submitted for your approval, here are a few articles on the most common amber dating techniques guiding our contemporary estimates. If you have time to browse a few, please feel free to do so — if not, you may skip right to the end of this article and take our word for it.

Geologists Have Faults Too

It is sad really, but we have yet much to learn before we can fully understand earth’s aging process. There are of course about 40+ dating techniques, yet those that can be applied to Dominican amber are still ambiguous at best and suggestive at worst.

The conclusion is that practically every dating technique has its ups and downs and its valid points; every age can in some way be argued as correct. None are superior to the other and it’s only the combination of all of them that give us an Educated Guess.

Geology (also known as the School of Rock) has the (nasty?) habit of hammering dating-results into its preconceived geological time frame. Sarcastic as I try to be, there is little reason to presently doubt this time-frame (far-fetched it may sound at times). The numbers suggested range anywhere between 100 million to as young as 10 million, but the most commonly agreed upon number for Dominican Amber is pegged at 20 - 30 million, critiques notwithstanding.

More or less. Approximately. Sort of.

You get the picture. The true answer for the age of amber remains as elusive now as it did at the beginning of this article, only more so.

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A few Citations:

• Manuel A. Iturralde-Vennet 2001. Geology of the Amber-Bearing Deposits of the Greater Antilles. Caribbean Journal of Science, Vol. 00, No. 0, 141-167, 2001

• Jackman, T.R., Larson, A., de Queiroz, K., and Losos, J.B. 1999. Phylogenetic relationships and tempo of early diversification in Anolis lizards. Systematic Biology, 48:254-285.

• Roughgarden, L. 1995. Anolis lizards of the Caribbean: ecology, evolution, and plate tectonics. Oxford University Press.

  Martin, G.E; Zekter, A.S., Two-Dimensional NMR Methods for Establishing Molecular Connectivity; VCH Publishers, Inc: New York, 1988 (p.59)

• C. Tuniz, J.R Bird, D.Fink, and G.F Herzog. 1998. Accelerator Mass Spectrometry: Ultrasensitive analysis for global science. CRC Press.

• Badash, Lawrence. 1968, “The origin of radioactive dating techniques” Am. Philos. Soc. Proc. 112(3), pp.158-169.

• Joseph P. Hornak, Ph.D. “The basics of NMR” 1997-2004 http://www.cis.rit.edu/htbooks/nmr/