{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

F13 quiz 1 condensed notes

Indeed a single tree can encompass all of life as we

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: s easily detected in the rocks, due to the “invention” of hard parts, did not appear until about 0.54 billion years ago, the beginning of the Cambrian Period. Interestingly, Precambrian rocks are found exclusively on continents; all oceanic rocks are younger. On the continents, Precambrian rocks today are often covered by younger sedimentary deposits. An unconformity is a buried surface of erosion. We can consider the amount of time during which erosion occurred, as well as the time represented by the rock that was removed, as “missing time” from the geologic record. When Precambrian rock lies beneath an unconformity, it is often called “crystalline basement.” Precambrian shields (not to be confused with shield volcanoes), in which Precambrian rocks crop out on the Earth surface, are located on every continent. They are areas of great size (the Llano Uplift here in Texas is too small to be a shield), and low elevation. Rocks in shields often feature signs of great deformation, evidence that at some point in the past they were the scenes of violent activity. Nowadays, however, shield regions are exceptionally stable. They are excellent exploration grounds for ore deposits (metals, diamonds), but not for oil. LECTURE 9: ORIGIN OF LIFE ON EARTH The histories of life and of the Earth are inextricably intertwined; one can’t be understood without the other. Life can be considered as...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern