NOAA Teacher at Sea
Onboard NOAA Ship Oscar Dyson
July 26 – August 12, 2011
Mission: Pollock Survey
Geographical Area of Cruise: Gulf of Alaska, Kalsin Bay
Heading: 213.0 (Stationary)
Date: August 6, 2011, 11:24 pm
Weather Data From the Bridge: click to view station model
Dry Bulb Temp: 10.8C
Wet Bulb temp: 9.9C
Skies: Partly Cloudy, Stratocumulus
Pressure: 1013.3mb, falling then steady
Science and Technology Log
As part of our stay on shore, we took some time to travel out to a place called Fossil Beach. Fossil Beach is located on the south-eastern side of Kodiak Island, on Chiniak Bay. It is a popular attraction on Kodiak because it is near the Kodiak launch complex (a defense missile base !) and it is a popular surf beach. I, however, find it incredible for a completely separate reason: an utter abundance of fossils!
There isn’t much background information to be found on Fossil Beach. The greatest extent one might find on the internet is “Drive southeast on the only road out of Kodiak. Find fossils.” To the layperson going out fossil hunting, that should be enough information. But for me, however…I wanted to know much more about the conditions of formation, the types of fossils found there, and the age of the rocks in which I was digging. As it turns out, if I wanted to dig up information on Fossil Beach, I would have to be as clever as I was the day I discovered so many of our extinct marine critter shells. This experience turned into a bit of a scientific research project for me, as I formed hypotheses, tested my predictions, and revised my original ideas based on new findings. This, kids, is science.
Walking around the outcrop gave some insights into the environment in which this rock strata formed. The fossils were definitely nested in dark, muddy shale. I noticed lots of mollusks, particularly clamshells, at first glance. Shells were deposited in big, thick, chunks and layers. What I noticed initially is that they weren’t really fossils. A fossil, by definition, has been mineralized to a certain extent. These weren’t. However, some scientists conclude that the actual fossilization process is not necessary to call a particular dead animal a fossil – the only requirement is an extended period of time locked up in a rock.
What are the criteria for fossil formation? A dead critter needs rapid burial and possession of hard parts. An anoxic environment helps, as well. Most soft-bodied critters do not survive the fossilization process, as their flesh will decay so rapidly that there isn’t enough time to fossilize. It is not unheard of, however, to find soft parts fossilized. For example, a fly or mosquito trapped in amber is considered to be a fossil – its entire body intact in the clear, honey-colored stone.
My first question, of course, was “what was the environment of formation for this particular set of fossils?” Meaning, what type of environment did these critters live in before they croaked? We can narrow it down to two distinct, but broadly categorized areas: land? Or sea? Well, let’s think for a moment about the standard conditions for fossil formation and use that to define the environment of formation. Criteria 1: Rapid burial. Criteria 2: Possession of hard parts. Criteria 3: Anoxic environment. Consider for a moment rapid burial. In what places may we find rapid burial? Volcanic eruptions? Maybe. Land or mudslide? Also a viable solution. The next step is to rule out (or in) these two options. In a volcanic eruption, the fossils would most certainly be nested in a layer of ash. In a mudslide or a landslide, these critters would be nested in coarse-grained rock like sandstone. In our mystery case, we have fossils buried in a shale – which is a fine-grained, silty rock associated with slow-moving or stagnant water. Neither of these options work.
Let’s try criteria 2 – possession of hard parts. These shells are mainly mollusk – in particular clam shells. Where do clams live? The water. It wouldn’t make sense for a clam to be fossilized in the middle of the desert, now would it? In addition, the presence of shale does not necessarily indicate rapid burial, but it does indicate that if it were at the bottom of the ocean, it would be undisturbed for many years as it was buried.
Criteria 3 – an anoxic environment. In this case, if a clam dies at the bottom of the ocean, it may be considered an anoxic environment, but not for certain.
Hypothesis: confirmed. These critters once roamed our seas, based on Criteria 2.
The next question to ask was “how long ago did the fossilization party take place?” This one is a little more difficult to answer, but with some stealthy sleuthing and some assistance from my fellow Teacher at Sea, Cat, we came to a reasonable conclusion regarding the time frame.
At first glance on a large geologic map of Alaska, Fossil Beach is described as a Paleozoic Era beach. However, this map was so broad and basic that if we were to “zoom” in on it right down to fossil beach, our perceptions would change about the age and conditions of formation.
I thought I saw large ammonite fossils at the beach, which would have confirmed my suspicions about a Paleozoic beach. What didn’t fit, however, was that the mollusk fossils were not “fossilized” – and a Paleozoic/Mesozoic fossil like an ammonite would make the rock layers any age between 542 and 206 million years old. Now, it’s not completely unheard of to find fossil in your midst that has retained all of its qualities and still be extremely old – there are a few fossils out there that are considered fossils, but haven’t “fossilized” in the traditional sense. But 206 million years? One would suspect that is plenty of time for a fossil to fossilize. It didn’t jive. This was my first clue that maybe this beach was much younger than the broad geologic map suggested.
The broad geologic map is a bit like a mosaic. When viewed from far away, all a person may see is the color “blue”. Up close, however, the intricate pieces that make up the mosaic are individually selected for their different shades and textures. With the broad geologic map of Alaska, I discovered it wasn’t detailed enough to give me the information I needed. At a distance, there is one big picture – the colors on the map key indicate that the rock formations that make up Kodiak are predominantly Paleozoic Sedimentary rocks. This is a bit like calling a brand new pair of Louis Vuitton peep toe black patent leather heels “shoes.” It just doesn’t do it justice.
After looking further, Cat found a great article published online that discusses the nature of the formation of the beach. (I will cite it at the end of the post). Most of the information following comes from that particular document.
The paper focuses on Sitkinak Island, an island just to the south of Kodiak, but it also mentions that the formation of rocks is one and the same. The Kodiak formation is just a bit younger. As it turns out, the rocks are deposited as part of the Narrow Cape Formation, a late Oligocene/early Miocene formation. This translates into somewhere on the order of 10 million years old or so. In particular, the paper cites the Juanian stage, which is the time frame that encompasses the last portion of the Oligocene and the first portion of the Miocene.
Even more interesting is that this paper reveals the type of ocean these particular fossils came from. They originated from the outer edge of the neritic zone to the continental shelf. If you recall, the neritic zone is the point at which the lowest of the low tide is all the way out to a depth of 200 meters. Furthermore, the study reveals that the water was a cool-temperate marine climate, which means that the warmest water at the surface was about 10oC for approximately 3-4 months out of the year.
It was great to uncover the mysteries of fossil beach. The only mystery remains is, what about the Ammonite I thought I found? At this time, I absolutely cannot reconcile what happened there. There are a couple of strong leads in terms of solutions to this question: first, it may not be an ammonite at all. Second, the broad geologic map does indicate Paleozoic sedimentary rock, which would be a perfect candidate for a critter like an ammonite. Maybe the ammonites were from a completely different rock formation?
Until I get back to land and get my hands on a copy of the Roadside Geology of Alaska (I looked everywhere in Kodiak to no avail!) this will have to suffice for my level of satisfaction with respect to fossil beach. Check back to this blog often to see if my predictions were right!
Well, wouldn’t ya know it? A tsunami line is painted right on base here at the Coast Guard! There is no reason to travel or hike a ridiculous amount when you can just stay right here and visit. (However, for more information on ridiculous Alaskan hikes, please visit my other blog at www.mrsdisonaboat.blogspot.com – you’ll love it.) We did see the line on the first day, I just haven’t had time to blog about it again, plus it took a considerable amount of time for me to finally get up the nerve to ask someone to stop a car so I could snag a picture!
It didn’t look that imposing at first. At first glance, it looked like it was only about 3 or 4 feet from the ground. I thought to myself, “Gee, this doesn’t look so bad…” until I walked up to the line. It was bigger than I was! Holy cow! Even if I reached my arms all the way above my head, I couldn’t touch the lower portion of the line. The picture is extremely deceptive, that’s for sure! I thought about what it would be like to be a person who hears the siren warning of the impending emergency, and what it would be like to make for higher ground, hoping that however high you climbed would be enough to save you from the wicked influx of water.
Eesh… I am thankful that so few lost their lives, but the sight of that line is a bit imposing. Also (and not at the expense of the destruction, of course) wickedly, beastly cool.
In other news, we have successfully thrown off the bow lines and set sail! We were supposed to head out yesterday, but then something went wrong with the water system, causing a delay, and then one of the officers got sick and had to go home. Luckily, we had a replacement officer standing by to take over. We are so sorry that she came down ill, but so grateful that we had someone to take over! As we left Women’s Bay this morning, I saw many otters playing about in the bull kelp. Those little critters are too dang cute for words! They poked their heads up for a few moments before doing a graceful backflip back in to the water. But the most impressive sight of all took place about thirty minutes after we set sail. Up on the flying bridge, we saw the telltale blow of a whale. This was followed by two or three playful fluke slaps on the surface of the water.
And then, because he (or she) was as excited as we were to be sailing, the whale performed for us the most impressive breach! You, go, sister! We like the ocean, too! In my fumbling wonder, I of course, took 9 or so pictures of the breaching whale using stop-motion photography for you to see below. Too bad Marshmallow is in the way.
I am so happy and thankful to be out on the sea. Now I see why people love it so much. It has an interesting dichotomy. On one hand, I feel so small – a large, blue, fog-covered expanse stretches out before me, nothing in sight for miles and miles. On the other hand, I feel enormous. As we left the bay, we traveled past the peninsula we had walked on so many times before. Along the shoreline was an oil spill containment kit stored in a freight-train style container. It looked so tiny from where we stood on the flying bridge. It was as if we swapped positions – now we were the behemoths, and the spill kit was nothing more than a busted up shoreside lego.
I’m fascinated by the scales of this magnificent place – more so about how I fit in to them. Everywhere I turn, the sizes of things – animals, projects, decks, horizons, anti-seasick meds, stories, waves, meals, ocean expanses, rock outcrops – everything, everything is large, even that which is the tiniest and seemingly insignificant. Here is the place where small things commit powerful acts – a tiny three-foot swell makes its presence known in more ways than one, and a small anti-seasick pill can keep me from worshipping at the feet of its effects. A big ocean can throw around an enormous ship, and a humpback whale can effortlessly cut through it with its imposing fins. A project seemingly small (at least in this context of one ship, one crew, one survey leg, and one set of scientists) can spread awareness about the health of our fisheries to a something the size of a nation. To top it off, we are completing it along the coast of our largest state – one that blends quietly in with our neighbors to the north, but not forgotten as a beautiful and expansive supplier of natural resources. Everything small is large out here, and everything large is large. For those who have spent too long at the dock, today they are home. For those who have never left a dock before, today we feel your freedom. And we love it, too.
*Information on Sitinak Island/Fossil Beach was summarized from the following:
Allison, Richard C. A late Oligocene or Earliest Miocene molluscan fauna from Sitinak Island, Alaska. United States Department of the Interior, Washington; 1981.