National Fossil Day is Tomorrow! Do You Know the Paleontological Heritage of Your Region?

A hadrosaur skull similar to Saurolophus, the first dinosaur ever found in California

Tomorrow is National Fossil Day, which if anything, is of far greater interest than a holiday concerning an Italian explorer discovering a Caribbean island a few hundred years ago. One of the really exciting changes in our region is that our fossil heritage is being celebrated, pretty much for the first time. We finally have a museum with the room to adequately showcase the incredible paleontological history of the Great Valley of California. If you've read my blog at all, you'll know it's the Great Valley Museum at Modesto Junior College.

Two fossils here, but one of them isn't quite dead yet. The other is a Mosasaur

The Great Valley of California has a rich history of fossil discovery. Sediments were accumulating here in Jurassic and Cretaceous time, so dinosaurs and other reptiles have been discovered here, although not in concentrations like those of the continental interior. The first dinosaur ever discovered in California was found in our county. It was a Saurolophus, a variety of duck-billed dinosaur (the hadrosaurs). It was found by a teenager exploring Del Puerto Canyon in the 1930s.

Even more interesting, especially in light of a certain dinosaur movie last summer, are the Mosasaurs, large marine reptiles that were the terrors of the Cretaceous seas. One of them, Plotosaurus bennisoni, was discovered by the same kid who found the Saurolophus. It may have been 35 feet or longer in length.

Some fossils are more mundane, but they're exciting because I found them. Those would include these Jurassic wood fragments from the Sierra Nevada foothills. They were carried into the ocean by turbidity currents in the vicinity of the subduction zone that was once active here.

The most diverse and plentiful fossils are those of the creatures that grazed and hunted up and down our valley in Pleistocene time. The Fossil Discovery Center in the Madera area a few miles south of us has the best collection on display of these animals. The animals include the sometimes terrifying Short-faced Bear, Saber-tooth Cat, American Lion, and Dire Wolf. The grazers included a number of species of horse, camel and antelope, as well as mammoths and giant ground sloths. Many other smaller animals have been found in the quarry at Madera (which doubles as the sanitary waste disposal pit).

Few people in our county and region have had a venue in which they could learn about this fascinating fossil history, which is why the newly opened Great Valley Museum is such a wonderful opportunity. We have a full-sized skeleton of a Saber-tooth Cat, and a life-sized Mosasaur skull.

The newest exhibit highlights the research being done in Miocene sediments of the Mehrten Formation near Turlock Lake by the faculty and students of California State University, Stanislaus. Former MJC student Jake Biewer designed the current exhibit. The students are investigating some of the fossil sites where six-foot long "saber-toothed" salmon remains were found, along with tortoises the size of those found on the Galapagos Islands. Other exhibits are currently in the planning stages.

It's hard to describe how exciting it is to finally have a place to tell the story of the fascinating animals that lived here before us. The response from the children of our valley has been infectious. They love finding out that their home was once the home of that terrifying creature from the dinosaur movie, but also that they themselves could be the one who makes the next great discovery.

Have a great fossil day tomorrow! Learn something new about the place that you live!

Driving Through the Most Dangerous Plate Boundary in the World: In the Pleistocene, a Different Kind of Danger

An Egret and Tule Elk at the San Luis National Wildlife Refuge near Los Banos

The Great Valley began as a shallow sea (a forearc basin) between the Mesozoic subduction zone and the Ancestral Sierra Nevada volcanic arc. As noted in the previous post, the sea filled with thousands of feet of sediments, and as the subduction zone transitioned to a transform boundary, the sea gave way to land, and the one of the most fertile valleys in existence emerged. The Great Valley has become one of the most important agricultural regions on the planet. 95% of the original landscape has been altered to grow food and feed. If the land isn't covered by crops, it's covered by pavement and cities.

The Cosumnes River Preserve north of Stockton

As I said in the previous post, the agricultural development isn't necessarily a bad thing. With an increasing population of mouths to feed in the world, it would be silly not to utilize the richest soils on the planet. But we do live in a highly interconnected ecosystem, and we need to preserve what we can of the richness and diversity of life in our world. A few wetlands have been protected from development to allow the survival of some of the migratory birds that overwinter in our valley, like the Sandhill Crane, the Ross's Goose, the Snow Goose, and many others. Some of the rivers flowing through the valley are still allowed to reach the sea, preserving salmon and other aquatic species. There is a great deal of conflict about where to define the limits of water and land use, especially in this horrific drought year.

The Cosumnes River north of Stockton

This past year I spent as a new birder has been a revelation as I have sought out those small corners and edges of the valley that preserve something of the original ecological richness. I was stunned to find that flocks of tens of thousands of cranes and geese spend their winters just a few miles from my home near Modesto.

Snow Geese and Ross's Geese at the Merced National Wildlife Refuge

Tule Elk, among the largest members of the deer family (aside from the Moose), used to live in the valley by the millions as well. One subspecies was down to a single breeding pair in the late 1800s, but they were protected by a rancher, and several thousand now survive in some widely separated refuges. The wolf was driven to extinction, as was the terrifying California Grizzly Bear. Other species retreated into the Coast Ranges and Sierra Nevada foothills.

The Tule Elk herd at the San Luis National Wildlife Refuge

This blog series has mostly been about the "most dangerous plate boundary" in the world, referring to the geologic hazards inherent in living near an active subduction zone: earthquakes, tsunamis, and volcanic eruptions. But a different kind of danger lurked in the Great Valley when humans first arrived: the so-called "megafauna": an ecosystem of large mammals that mostly went extinct just 10,000 or so years ago.

Wooly Mammoth at the Paige Museum

One of the most imposing creatures would have been the mammoths. These elephant relatives were widespread across Asia, Europe and North America, and passed into oblivion only a few thousand years ago. They were gone from the continents by 10,000 years ago, but a small population (both in stature and in numbers) survived on Wrangell Island in eastern Russia until 4,300 years ago.

There were giant ground sloths (above), and camels. Lots of camels, so much so that they are one of the two most common animals found in the Fairmead paleontological site near the Great Valley town of Madera. The Fairmead excavations have been the most important source of fossil material on the valley floor (the fossil species are also well known from the La Brea Tar Pits in Los Angeles.

The other common fossil is the horse. Most people think horses came to America with the Spaniards in the 1500s, but they actually evolved in North America and spread to other parts of the world before going extinct in their ancestral home around 10,000 years ago. There were also species of deer and pronghorn, and the buffalo roamed the valley as well.

Though any of these creatures could have injured humans in self-defense, it was their predators that would have made life in the valley terrifying. There were huge Sabertooth Cats. There were Jaguars and American Lions (pretty much the same as African Lions).

The California Grizzly Bear was dangerous enough, but even larger bears lived in the valley as well. The Short-faced Bear was a good 50% larger than a Grizzly, and may have been the largest terrestrial mammal predator ever. They were five feet high at the shoulder, and stood 11-12 feet tall if they chose to. Terrifying indeed.

They were smaller than the cats or bears, but the Dire Wolves hunted in packs, and that made them perhaps even more dangerous than the others. They were 25% larger than today's wolves.

The Great Valley would have been a dangerous place for humans when they arrived 13,000 years ago or earlier. It's possible that the megafauna is extinct today because humans had tools for hunting and defense, but the connection is not yet clear. Climate change could have played a role too, or disease, or any other number of possible explanations. In any case, I feel a sense of loss when I wander through the few remaining pieces of original habitat imagining the creatures that used to live here. A sense of loss, but at least I am not so fearful of being maimed or killed.

Are you interested in seeing more of these creatures? If you are ever traveling in the Great Valley for any reason, make the time to stop at the Fossil Discovery Center in the Madera area. The very famous La Brea Tar Pits are the other great source of information on the extinct megafauna. The Paige Museum at the tar pits is an excellent place to visit when you are in Los Angeles.

Driving Through the Most Dangerous Plate Boundary in the World: The Sea Floor that Became the Greatest Agricultural Region on Earth

Welcome to one of the strangest places on the planet! It's the size of West Virginia, but flatter than the Mississippi River Valley. It was once America's Serengeti, but 95% of the original landscape has been altered. It originated as the bottom of a sea, but now grows most of the nation's produce, and practically all of the nation's walnuts, almonds, and pistachios. It has been a major oil and natural gas producer. It is the Great Valley of California.

The Great Valley originated as a forearc basin, the seaway that is sometimes present between an oceanic trench/subduction zone and the margin of the continent. Tens of thousands of feet of sediment were deposited between the Jurassic Period and the mid-Cenozoic. As noted in the last post, the sediments have yielded up a fascinating collection of fossils over the years, including mosasaurs, plesiosaurs, ichthyosaurs, and even the fragmentary remains of a few dinosaurs. The valley was a seaway for the better part of 200 million years.

It is no longer a seaway. In the last few million years, California's tectonic framework underwent huge changes. The subduction zone was extinguished in the central and southern parts (subduction continues in the north state). A new plate boundary emerged: the San Andreas transform fault. Compressional forces along bends in the fault line raised the Coast Ranges, and the seaway of the Great Valley slowly gave way to river deltas, and then alluvial fans. In the last five million years, the Great Valley has been a terrestrial environment, with numerous river channels, gigantic lakes and vast grasslands. Large herds of grazing animals wandered the plains, pursued at times by terrifying predators (look for them in the next post of the series). Countless millions of birds made use of the wetlands during their long seasonal migrations.

The biggest and most far-ranging change in the Great Valley during the last five million years may have been that which took place only in the last 150: agricultural development. Millions of acres of grasslands, lakes and wetlands were drained and plowed. The rivers were dammed and diverted into artificial watercourses that took them hundreds of miles from their natural channels. Thousands of wells were drilled that brought prehistoric groundwater to the surface. Parts of the valley subsided thirty feet or more as the water was withdrawn. A mere 5% of the valley floor retains its natural character. Most of the animals are gone, shot to extinction (the California Grizzly Bear, for instance), or pushed to marginal environments in the Sierra Nevada or the Coast Ranges. The migratory birds are crowded into a few precious wildlife refuges up and down the valley.

I'm not really writing this to criticize the agricultural development of the valley. We have billions of people on the planet, and they insist on eating, so it would be foolish not to utilize some of the richest soils on the planet. I would even suggest to people who don't live in the valley that they might have a bit more respect for the people who work hard for low wages to plant and harvest the food that you eat. On the other hand, we do a lot of things wrong in our approach to agricultural development, and the waste of water is one of those things. The ongoing four-year drought has exacerbated the problem. There are problems with the overuse of pesticides and antibiotics, and with agricultural waste disposal. In many ways we are fouling (and paving over) our nest.

Still, living here does have some benefits. Given our journey through the most dangerous plate boundary on the planet, the Great Valley doesn't exactly look geologically menacing. It is relatively far away from the most active earthquake faults of the state, and is even farther away from the most dangerous of the state's volcanoes. We don't get hurricanes, violent thunderstorms or blizzards, and tornadoes are exceedingly rare. The idea of dangers from landslides is laughable (except that I know of at least one fatality in Modesto caused by a slide). But we do have two threats: droughts and flooding.We are in the midst of the worst drought in recorded history, but with the development of an El Nino weather pattern in the Pacific, we could have catastrophic floods in only a few months. We can never really predict what can happen. In 1861-62 the floods were widespread that the state capitol had to be removed to San Francisco for a few months. The valley was a gigantic lake twenty miles wide in places.

Flooding on the San Joaquin River in 2006.

The map below shows what could happen if we get a repeat of the 1861-62 floods, an event the meteorologists call an atmospheric river storm (ARKStorm). They also refer to this as the "other big one", because the potential for damage is greater than that of a major earthquake, at least in the Great Valley.

In the Great Valley, geology conspired to transform a sea floor into the richest agricultural region on the planet. For all the flat lands, it is an interesting place to study. In the next post we'll take a look at the strange things we've found just beneath the surface. In a garbage dump of all places.

The Community Hates Science SO MUCH (not). A Weekend at the Mineral Show

As we all know, science has no hold on the imagination of the young and old in our society, nobody cares about rocks, minerals, fossils, and all that stuff. I mean, one could offer a show with that stuff, and we simply realize that no one would show up.

Or maybe not. Every year, events seem to prove the opposite. For many years, our local Mother Lode Mineral Society has held their Rock and Mineral Show at the Stanislaus County Fairgrounds in Turlock and did so this last weekend. Thousands of community members, old, young, and in-between, showed up, as they always do. If you follow these sorts of things, you can imagine that there are lots of concessionaires hawking their wares, and you'd get the feel that the whole thing is a gigantic sales event. And if they're just selling stuff, why even show up?

The Modesto Junior College Geology Club displays fossil replicas of previous inhabitants of our Great Valley

But the Turlock show is special and different. They devote a huge amount of space for education. There are dozens and dozens of wonderful displays of all aspects of earth science, including paleontology, minerals, rocks, mining, and environment. They make a point of inviting related groups to put up tables, including our new Great Valley Museum, the Geology Club at Modesto Junior College, and many others. They have excellent speakers on numerous topics. The kids who attend, parents and grandparents in tow, have a great time. They are fascinated to find out tidbits of information about their home environment, including the fact that Mosasaurs, dinosaurs, wooly mammoths, giant Short-faced Bears, and many other creatures used to live here at different times in the past.

Coelacanth fossil

We have some serious fans of paleontology in our area, and every year brings some new discovery. They had a Coelacanth display with seven different species of this ancient fish that was a precursor to the amphibians (they had lobed fins instead of rayed fins; their bottom-crawling lifestyle led to legs later on). I don't think I've seen that many in one place in any museum.

Dunkleosteus and a Coelacanth, two ancient orders of the fish family. Dunkleosteus grew to a length of thirty feet or more. The Coelacanths, thought extinct until one was discovered in 1938, is one of the rarest orders of fish in the world.

After seeing all the cool displays, a lot of people end up hoping to secure some samples of their own, and the concessions seem to do good business. I would never fall for any sales ploys, of course.

Or not. I ended up with a beautiful piece of laboradorite feldspar with its iridescent blue sheen, a nice rhombohedral cleavage fragment of orange/gold calcite, and my favorite item, the tooth of a juvenile Wooly Mammoth. All for their educational value, of course.

Woolly Mammoth a Star!

Many of you have wondered about the woolly mammoth mentioned on my office phone answering machine. Well, she's a star! I rented her to McD in the Netherlands for an ad. Via Lockwood, via Laelaps, here it is ...



In the interest of full disclosure, I don't really have a wooly mammoth in my department. I do have a sabertooth cat, though.