EARTH S HISTORY. What is Geology? logy: science. Geology is the scientific study of the Earth, including its:

Size: px

Start display at page:

Download "EARTH S HISTORY. What is Geology? logy: science. Geology is the scientific study of the Earth, including its:"

Bruce Watson
6 years ago
Views:

1 EARTH S HISTORY 1 What is Geology? Geo: earth logy: science Geology is the scientific study of the Earth, including its: composition, structure, and physical properties. 2 1

2 Geologists study: the origin and evolution of our planet; the chemical and physical properties of minerals, rocks, and fluids; the structure of our mobile crust - its newly forming ocean floors and its ancient drifting continents; the history of life; and the human adaptation to earthquakes, volcanos, landslides and floods. 3 Geophysics is the study of the Earth by quantitative physical methods. It is an applied science and includes the Earth s interior crust, oceans, and atmosphere. Geochemistry is the study of the distribution of chemicals in the Earth and atmosphere. Geomorphology is the study of landforms and underlying structures. 4 2

3 Paleontology is the study of past life observed in the geologic record (fossils). Tectonics deals with large scale Earth structures such as tectonic plates and its deep interior. Volcanology is the study of volcanoes and volcanic processes

4 7 8 4

5 Earth s History 10 to 15 billion years for the age of the Universe (based on the recession of distant galaxies) 11 to 13 billion years for the age of the Milky Way Galaxy (based on the stage of evolution of globular cluster stars) and 4.54 billion years found for the Solar System and Earth. 9 What are we made of? The Big Bang The story of the Universe starts about 14 billion years ago with the Big Bang. This was a huge explosion that brought the Universe into existence. Before the Big Bang, there were no laws of physics, no time and no particles. 10 5

6 Starry night After many hundreds of millions of years, much of this matter was pulled together into clumps under its own gravity. These clumps became immensely hot in the process and the first Stars were born. The matter contained in your body has, at one time or another, been part of at least one star. 11 The Beginning of Earth 4.5 billion years ago the Earth is born from a cloud of dust and fire orbiting the sun. There are no seas upon the barren Earth. The sun blisters down as poisonous gases swirl about. Racked with volcanoes, bombarded by asteroids and comets, Earth is incredibly hot with a sea of molten rock covering its surface. The early Earth is a world in slow turmoil for many, many thousands of years. 12 6

7 Sea of molten rock 13 The cooling of this mass formed: the "lithosphere" (land: the earth crust and interior mass), "hydrosphere" (zone of water: oceans, lake), "atmosphere" (air: gaseous envelope surrounding the hydrosphere and lithosphere). 14 7

8 Layers of the Earth By analyzing the seismograms from many earthquakes, scientists t have discovered d that t three main levels or shells exist within the Earth: CRUST MANTLE CORE 15 CRUST MANTLE CORE 16 8

9 17 The Core The Core is predominantly composed of iron and nickel. The matter with the highest density (mostly iron) sinks to form Earth s solid inner core. Even after 4.5 billion years of cooling, the Earth's core remains very hot. 18 9

10 The Earth's core The Earth's core is divided into two layers: a solid inner core, and a liquid outer core. 19 The Core The Inner Core is solid nickle-iron alloy. The Outer Core is a molten nickle-iron alloy

The mantle Surrounding the inner and outer core is the mantle

11 The mantle Surrounding the inner and outer core is the mantle The Mantle is approximately 2885 kilometers thick and is the middle layer of the Earth. The Mantle is made up of minerals rich in the elements: iron, magnesium, silica, and oxygen. The mantle is relatively flexible so it flows instead of fracturing. The Mantle makes up approximately ~85% of the Earth's volume

12 23 Earth s crust The Earth's outer layer, the Crust is 4 to 60 kilometers thick. The crust is: relatively light, brittle and rocky material rich in the elements oxygen and silica with lesser amounts of aluminum, iron, calcium, potassium, sodium, and magnesium

13 25 Most Common Chemical Elements in the Earth Element Weight Percent Oxygen O, 46.6 Silicon Si, 27.7 Aluminum Al, 8.1 Iron Fe, 5.0 Calcium Ca, 3.6 Sodium Na, 2.8 Potassium K, 2.6 Magnesium Mg, 2.1 Others

14 Most(74.3%) of the minerals in the Earth's crust contain Oxygen (O) and Silicon (Si). This is why the Silicate mineral family (minerals having the ion SiO4) compose 90% of all rock forming minerals

million years ago 29 Cenozoic Quaternary Holocene 0.

Oligocene 34 Eocene 55 Paleocene 65 Mesozoic Cretaceous

Paleozoic Permian 290 Pennsylvanian 323 Mississippian

15 million years ago 29 Cenozoic Quaternary Holocene 0.01 Pleistocene 2 Tertiary Pliocene 5 Miocene 23 Oligocene 34 Eocene 55 Paleocene 65 Mesozoic Cretaceous 141 Jurassic 202 Triassic 250 Miilions of years Paleozoic Permian 290 Pennsylvanian 323 Mississippian 363 Devonian 409 Silurian 439 Ordovician 510 Cambrian 544 Precambrian

16 EON ERA PERIOD EPOCH DATES AGE of Notes Cenozoic Quaternary Neog ene Holoce ne Pleistoc ene Pliocen e Miocen e Oligoce ne Mammals Humans Tertiary Pale ogen Eocene e Paleoce ne Extinction of dinosaurs Phanerozoic Cretaceous Flowering plants Mesozoic Jurassic Reptiles 1st birds/mammals Triassic First Dinosaurs Permian End of trilobites Pennsylvan ian Amphibians First reptiles Carboniferous Mississippi an Large primitive trees Paleozoic Devonian First amphibians Fishes Silurian First land plant fossils Ordovician First Fish Invertebrates Cambrian st shells, trilobites dominant Proterozoic 570-2,500 1st Multi-celled organisms Archean Also known as Precambrian 2,500-3,800 1st one-celled organisms Hadean 3,800-4,600 Approx age of oldest rocks 3, The Cenozoic (the Age of Mammals) (65 Million Years to the Present) The Cenozoic is the most recent of the three major subdivisions of animal history. The Cenozoic is sometimes called the Age of Mammals, because the largest land animals have been mammals during that time. The Cenozoic is divided into two main sub-divisions: the Tertiary (from 65 million years ago to 1.8 million years ago) and the Quaternary (includes only the last 1.8 million years) 32 16

17 The Mesozoic The Mesozoic is divided into three time periods: the Triassic ( Million Years Ago), the Jurassic ( Million Years Ago), and the Cretaceous ( Million Years Ago). 33 The Mesozoic Mesozoic means "middle animals", and is the time during which the world fauna changed drastically from that which had been seen in the Paleozoic. Dinosaurs, which are perhaps the most popular organisms of the Mesozoic, evolved in the Triassic, but were not very diverse until the Jurassic. Some of the last dinosaurs to have lived are found in the late Cretaceous deposits of Montana in the United States. The Mesozoic was also a time of great change in the terrestrial vegetation

5 Time Marches On. TAKE A LOOK 1. Identify What kinds of organisms formed the fossils in the picture?

5 Time Marches On. TAKE A LOOK 1. Identify What kinds of organisms formed the fossils in the picture? CHAPTER 6 5 Time Marches On SECTION The Rock and Fossil Record BEFORE YOU READ After you read this section, you should be able to answer these questions: How do geologists measure time? How has life changed