1. Wednesday November 14, 2012 (Introduction to the Geologic Time Scale; Begin Lab – The Geologic Time Scale)

2. The Launch Pad Wednesday, 11/14/12 List the major steps in the development of Earth’s atmosphere and oceans that lead to life on Earth as we know it today. Earth’s primitive atmosphere was formed by a process called “outgassing.” Water vapor condensed to form clouds and rainwater that formed the oceans. Oxygen levels in the atmosphere steadily increased as a result of photosynthetic bacteria in the ocean. Outgassing produced acidic conditions that caused an accelerated rate of weathering of Earth’s rocky surface. Products of this weathering were carried to the oceans, thus increasing the salinity of the oceans..

4. Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day Quiz 10S511/2 11/16 Video Activity – Fearless Planet – Earth Story F111/611/911/16 Quiz 11S111/9 11/30 WS – Origin of the Atmosphere and Oceans F211/1311/16

5. Recent Events in Science Happy Little Crater on Mercury www.nasa.gov/multimedia/imagegall ery/image_feature_2392.html Read All About It! It looks like this little crater on Mercury is happy! The central peaks of this complex crater have formed in such a way that it resembles a smiling face. This image taken by the MESSENGER spacecraft is oriented so north is toward the bottom.

6. The Geologic Time Scale

7. The Geologic Time Scale is a system of chronological measurement that relates stratigraphy to time. Stratigraphy is a branch of geology which studies rock layers and layering (stratification.) It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic stratigraphy or lithostratigraphy, and biologic stratigraphy or biostratigraphy, and is used by geologists, paleontologists, and other earth scientists to describe the timing and relationships between events that have occurred throughout Earth's history.

8. The Geologic Time Scale This scale divides geologic history into units, with the following subdivisions: Eons are the greatest expanse of time. There are three (or four) eons: Hadean - the first eon Precambrian - further subdivided into the Achaean and Proterozoic eons Phanerozoic - the most recent and current eon Eras are subdivisions of an eon. For example, the eras of the Phanerozoic eon are: the Cenozoic (“recent life”) the Mesozoic (“middle life”) the Paleozoic (“ancient life”) Eras are further subdivided into periods. Periods are further subdivided into epochs.

9. The Geologic Time Scale Eon Eras Periods Epochs

10. The Geologic Time Scale

11. Figure 11.19 The Geologic Time Scale

15. Begin Lab- The Geologic Time Scale