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Evidences of Fossils and Rocks

Evidences of Fossils and Rocks. Fossils and Rocks.

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Evidences of Fossils and Rocks

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  1. Evidences of Fossils and Rocks

  2. Fossils and Rocks • Rocks-a naturally occurring solid aggregate of one or more minerals ormineraloids. It is also composed of grains of minerals, which, in turn, are homogenous solid formed from a chemical compound that is arranged in an orderly manner. • Fossils -evidence of ancient life forms or ancient habitats which have been preserved by natural processes. They can be the actual remains of a once living thing, such as bones or seeds, or even traces of past events such as dinosaur footprints, or the ripple marks on a prehistoric shore.Fossils can be used to recognize rocks of the same or different ages

  3. Fossil Evidence Nicholas Steno's anatomical drawing of an extant shark (left) and a fossil shark tooth (right). Steno made the leap and declared that the fossil teeth indeed came from the mouths of once-living sharks.

  4. Indication or Interactions Clues at the Cellular Level

  5. Possibilities of Fossil Formation

  6. Types of Fossils -mold fossils- a fossilized impression made in the substrate - a negative image of the organism. -cast fossils- formed when a mold is filled in -trace fossils = ichnofossilsfossilized nests, gastroliths, burrows, footprints, etc. -true form fossils-fossils of the actual animal or animal part.

  7. Mold Fossil Cast Fossil Trace Fossil True Form Fossil

  8. Six Ways that organisms can turn into fossils unaltered preservationlike insects or plant parts trapped in amber, a hardened form of tree sap. Permineralization = petrificationin which rock-like minerals seep in slowly and replace the original organic tissues with silica, calcite or pyrite, forming a rock-like fossil - can preserve hard and soft parts - most bone and wood fossils are permineralized. replacement-An organism's hard parts dissolve and are replaced by other minerals, like calcite, silica, pyrite, or iron. carbonization=coalificationin which only the carbon remains in the specimen - other elements, like hydrogen, oxygen, and nitrogen are removed. Recrystalization-hard parts either revert to more stable minerals or small crystals turn into larger crystals. authigenicpreservation- moldsand casts of organisms that have been destroyed or dissolved.

  9. Distribution of FossilsOne of the first lines of evidence suggesting the existence of plate tectonics was the discovery of very similar fossils in rock masses separated by vast distances and by ocean expanses. It suggested that those land areas had in the past been connected.

  10. Evidence of Rocks -Rocks provide evidence for changes in the Earth. In 1785 James Hutton presented his idea of a rock cycle to the Royal Society. He detailed ideas of erosion and sedimentation taking place over long periods of time, making massive changes to the Earth’s surface. -Rocks also serves as evidence of the changes undergone by plates and continents.

  11. Geomagnetism -Earth's magnetic field is the magnetic field that extends from the Earth's interior to where it meets the solar wind, a stream of charged particles emanating from the Sun.

  12. The Magnetic Field Model Geomagnetic models form the foundation of traditional, compass-based navigational systems. These models provide a picture of the Earth's magnetic field and how it varies from one point on the Earth's surface to another. The primary world model is the International Geomagnetic Reference Field (IGRF), compiled from magnetic measurements collected by national observatories in many countries, as well as readings made from ships, airplanes, and satellites. The model, derived through mathematical analysis of a vast amount of data, represents the magnetic field generated in the Earth's core, with small-scale variations at the surface and solar effects filtered out of the basic data. Even in an age of Global Positioning System (GPS) navigation, when finding your position on the Earth's surface is just a click away, the geomagnetic model still plays a vital role, it is built into GPS navigation systems as a backup. The geomagnetic field model is also vital to various kinds of magnetic surveys, such as those used in mineral exploration and the mapping of hazardous earthquake faults

  13. The Earth as a Dynamo • The Earth's magnetic field is generated within its molten iron core through a combination of thermal movement, the Earth's daily rotation, and electrical forces within the core. These elements form a dynamo that sustains a magnetic field that is similar to that of a bar magnet slightly inclined to a line that joins the North and South Geographic Poles. A compass placed in this magnetic field thus does not point due north, declination measures the angle between the compass reading at any point on the Earth's surface and true north (measured in degrees). The geomagnetic reference model is the basis for establishing the declination and its variation across the surface of the globe.

  14. Components of the Magnetic Field • The direction and strength of the magnetic field can be measured at the surface of the Earth and plotted. The total magnetic field can be divided into several components: • Declination (D) indicates the difference, in degrees, between the headings of true north and magnetic north. • Inclination (I) is the angle, in degrees, of the magnetic field above or below horizontal. • Horizontal Intensity (H) defines the horizontal component of the total field intensity. • Vertical Intensity (Z) defines the vertical component of the total field intensity. • Total Intensity (F) is the strength of the magnetic field, not divided into its component parts.

  15. Inclination • Total Intensity

  16. Variations in the Earth’s Magnetic Field • The intensity and structure of the Earth's magnetic field are always changing, slowly but erratically, reflecting the influence of the flow of thermal currents within the iron core. This variation is reflected in part by the wandering of the North and South Geomagnetic Poles. Because a wide range of commercial and military navigation and attitude/heading systems are dependent on models of the magnetic field, these models need to be updated periodically. The magnetic field's strength and direction and their rates of change are predicted every 5 years for a 5-year period.

  17. Influence of the Sun • Electrical particles streaming from the sun cause the "solar wind" which warps Earth's geomagnetic field lines, flattening them on the sun-ward side and stretching them out on the downstream side. The influence of this distortion of the geomagnetic field is quite small near Earth's surface (except during solar eruptions associated with sunspots) and becomes larger with increasing distance from Earth.

  18. http://hyperphysics.phy-astr.gsu.edu/hbase/geophys/platevid.htmlhttp://www.bbc.co.uk/nature/fossilshttp://hyperphysics.phy-astr.gsu.edu/hbase/geophys/platevid.htmlhttp://www.bbc.co.uk/nature/fossils http://evolution.berkeley.edu/evosite/lines/Ifossil_ev.shtml http://pubs.usgs.gov/gip/fossils/succession.html http://www.enchantedlearning.com/subjects/dinosaurs/dinofossils/Fossiltypes.html http://nationalatlas.gov/articles/geology/a_geomag.html#one

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