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During the Second World War, linear bands of positive and negative magnetic anomolies were found in the ocean floor, stretching for hundreds of miles, with an almost perfect symmetry either side of mid-ocean ridges.
It was realised that these anomalies were evidence of periodic reversals of the earth's magnetic field. Molten basalt had been magnetised in the direction of the field and then cooled to 'fossilise' that direction. Each time the earth's magnetic field reversed, a stripe was added in the opposite direction.
What else can I help you with?
What do igneous rocks tell us about the earth?
ashoka
What is one way to tell whether a rock is limestone?
these parts are changed into special kind of rocks
What does the simile like rocks in the river mean?
The rock is changed by the river, like a person is changed by life experiences.
What is the science of rocks?
The science of rocks is known as geology. Geology is the study of the Earth's materials, including rocks, minerals, and the processes that shape the Earth's surface. Geologists study the different types of rocks, how they are formed, and what they can tell us about the Earth's history.
What 3 rocks on the earth?
I'm going to tell you right now there are a lot more than three rocks on earth. However, there are only three basic TYPES of rocks, and those are Sedimentary, Igneous, and Metamorphic.
Can large areas be covered with layers of sedimentary rocks?
Yes, massive areas of Earth are covered by sedimentary rocks. A good geology map will tell you what rocks are in your area.
How do you tell polarity?
what do ya mean by "Polarity" for the following parameters? Charge: Voltage: Current: Meter Probes:
How can rocks tell us about the history of the earth?
Rocks tell the story of the Earth. The Earth is made of rock, from the tallest mountains to the floor of the deepest ocean. Thousands of different types of rocks and minerals have been found on Earth. Most rocks at the Earth's surface are formed from only eight elements (oxygen, silicon, aluminum, iron, magnesium, calcium, potassium, and sodium), but these elements are combined in a number of ways to make rocks that are very different. Rocks are continually changing. Wind and water wear them down and carry bits of rock away; the tiny particles accumulate in a lake or ocean and harden into rock again. The oldest rock that has ever been found is more than 3.9 billion years old. The Earth itself is at least 4.5 billion years old, but rocks from the beginning of Earth's history have changed so much from their original form that they have become new kinds of rock. By studying how rocks form and change, scientists have built a solid understanding of the Earth we live on and its long history.
How do fossils tell how the earth has changed?
fossiles indicate how the earth ha changed. the older stuff is at the bottom, and the newer stuff is at the top. over time the top lyer erodes and the fossals are exposed.
What forces on earth cause rocks to form?
Rocks are made up of a materials. They can also contain some sediments and the fossilized remains of plants ans animals. Rocks aren't very rare. In fact, the Earth is made up of about six sextillion tons of rock. There are many different rock types on Earth. They are the result of the different natural forces at work on this planet. Rocks are so varied in color, texture, and composition that it seems impossible to identify them. It seems even harder to unlock the secrets of how they originated and how they came to be where you found them! The study of rocks is called petrology. With some careful observation and study, you can learn to read a rock like a book. Rocks are the record of our planet's past. They tell us where rivers use to flow, where huge inland seas were located, and what lived in these waters. The Earth's rocks tell us stories of the glaciers and of how the Ice Age changed the planet. The combinations of temperature, pressure, and chemical interactions at work within the Earth and on the surface have produced this huge variety of rocks. All rocks, however, fall into one of the three basic groups: igneous rocks, sedimentary rocks, or metamorphic rocks.
Is capacitor polarity sensitive?
Some capacitors are polarity sensitive; some are not. It depends on the design. Electrolytic capacitors, for instance, are polarity sensitive, while ceramic disc capacitors are not. You can generally tell, if the capacitor is marked with polarity signs, such as + and -, if it is or not.
Is it true when you study earth's interior geologists often rely on indirect such as evidence from fossils?
No. Fossils tell us about what was living at or near the earths surface in the past, they do not tell us about the Earth's interior. When studying the Earth's interior, geologists look at micro gravity variations (which tell us about density differences in deep rocks), magnetic variations (which tell us a bit about the deep rocks composition) and most importantly seismic records (which tell us about the physical properties of the deep rocks). We also look for deep rocks that have been brought to the surface during the collision of continents (the roots of mountains) and volcanic events (such as diamond pipes).
