Day 3:


Tectonics: has to do with earth movements, faulting, uplift, subsidence, doming, etc..

Evidence for vertical crutal movements is abundant.


Figure taken from Dana, 1894, Manual of Geology, 5th edition, American Book Company.

"The temple is that of Jupiter Serapsis at Pozzouli. ... supported by 46 columns, each 42 feet high, and five feet in diameter. Three of the columns are now standing, and they bear evidence of submergence for a considerable time to half their height. The lower twelve feet are smooth; for nine feet above this, they are penetrated by lithodomus or stone-bearing shells, remains of which (a species now living in the Meditteranean) were found in the holes. The columns when submerged, were consequently buried in the mud of the bottom for 12 feet, and were surrounded by water nine feet deep. The pavement of the temple is now underwater. Five feet below it there is a second pavement, proving that these oscillations had gone on before the temple was deserted by the Romans."


 

Basic definition of plate tectonics: the outer shell of the earth (the lithosphere) consists of distinct curved plates that behave relatively rigidly and move large horizontal distances with respect to each other at average rates of centimeters per year. Oceanic crust is formed at seafloor spreading centers and recycled into the mantle at subduction zones. Plate margins are areas of concentrated geologic activity.

Plate tectonics as a scientific revolution.

Lines of supporting evidence for plate tectonics:

What are the states of matter on the earth?

Definition of rheid behavior and glacial isostacy.

Continental vs. oceanic crust: this is a crucial distinction for the earth. The difference between them is like night and day.


Significance of plate tectonics from an environmental perspective?


Types of plate "boundaries" and geologic activity concentrated at plate boundaries.

Divergent: two plates move away from each other.

Convergent boundaries: two plates move towards each other.

Transcurrent:

Hybrids are common:

Links to other relevant sites:


Below are two maps showing the configuration of continents and oceanic basins 237 Ma ago and 100 Ma years ago. Compare them to each other and the present configuration and you begin to get some idea of how dynamic the outer shell of the earth is. These maps were generated by C. R. Scotese (cscotese@uta.edu).