Bring the kids, this EarthCache was designed for them! Plaza de la Paz was once at the bottom of a deep tropical ocean bay. Scientists and volunteers removed several hundred marine fossils from the 10 to 12-million-year-old sea-floor deposits during construction of this plaza.
History
Before being raised by subterranean geological forces, the land on which you stand was covered by sea water almost a mile deep! The abundance of diatoms, simple plans and other warm water organisms, in the soil here tell us that millions of years ago this area was more tropical than it is today.
Fossils Found Here
Paleontologists, scientists who study fossils, are able to identify baleen whales by their ear bones even when a complete skeleton is not found. Uncovering a Mixocetus eylsius fossil skull with its ear bones intact, as was the case here at Plaza de la Paz, represents a “major scientific find” as this is only one of two such fossils found in Southern California.
The Caracharocles megalodon lived from the Miocene to Pliocene periods (17 to 3 million years ago). An ancestor of today’s great white shark, the megalodon were rare, immense predators and occasionally inhabited the worlds deep oceans, but usually swam near shore to feed on migrating whales and other sea mammals. Whole sharks are rarely preserved as fossils because they have skeletons of cartilage rather than bone. From it’s teeth, we can tell many things about this ancient shark. Fossil megalodon teeth represent sharks that were ten feet long for every inch of tooth length.
To log this EarthCache:
On display here are replicas of the fossils found during excavation of the shopping center. Answer the following 7 questions for credit:
1) Measure the length and width of the mixocetus baleen whale fossil skull on display. (Located on the left side of the grocery store.)
2) Measure the length and width (in centimeters) of the fossilized baleen whale ear bones on the plaque.
3) Measure the length and width (in centimeters) of the fossilized megladon tooth on the display kiosk. (Located on the right side of the grocery store.) **The plaque is now behind the glass, so please estimate.**
4) According to the plaques, which of the two extinct species (Caracharocles megalodon or the Mixocetus eylsius) was longer in length.
Answer the following questions using Page 9, Figure 3 and Figure 6 of the "Orange County Archaeology and Paleontology Guidelines, Procedures, and Policies" document located at http://www.ocparks.com/uploadgraphics/Overview201-7FinalReport.pdf and http://www.ocparks.com/uploadgraphics/OverviewFinalReport2.pdf
5) Fill in the blanks. "This embayment may have been an ancient ______ ______ for whales, and hence a "______ ______" for sharks.
6) Based on the time periods/epochs from the plaque, which geologic formation would the mixocetus have likely be found in?
7) Based on the time periods/epochs from the plaque, Which geologic formation would the caracharocles have likely be found in?
Email us the answers by clicking on our name at the top of the page. Feel free to post pictures of the large displays as long as no answers are present.
EarthCache for Earth Science Week
Earth Science Week begins again this year with International EarthCache Day on Sunday, Oct. 14, 2007. Whether you’re a teacher, a student, or just someone who enjoys experiencing Earth science firsthand, EarthCaching provides a great way to kick off the celebration. For more info visit: http://www.geosociety.org/educate/earthweek.htm
PDF Source from wraavr:
Thank you wraavr for providing the PDF files that contain answers to some of the questions the plaques use to have.
- Overview201-7FinalReport.pdf (downloads or opens a PDF, depending on your browser)
- OverviewFinalReport2.pdf (downloads or opens a PDF, depending on your browser)