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Question: please help me answer questions 2 amp 3 using this...

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Please help me answer questions 2 & 3 using this information given. Also is 1 correct? Thank you in advance
If the slate layer contains a large number of trilobite fossils, and fish fossils are very rare, what is its probable age? 2. 6005 miln If the volcanic ash on top of the limestone layer is radioactively dated as 230 million years old, and the limestone layer contains both sharksteeth and trilobite fossils, estimate the probable age range of the limestone. 3. Based on the types of rocks and fossils found in this geologic column, and their arrangement, what was the nature of the environment in this area of the world during the first half of the Paleozoic (600-300 million years ago)? 4.
Using Figure 2.3, determine the age of certain rock strata by using both relative and radioactive dating methods. Use the following geological principles to help you answer the questions Stenos Principle of Horizontality-Layers of sediment are originally deposited horizontally under Stenos Principle of Superposition- Sedimentary layers are deposited in a time sequence, with the the action of gravity. oldest on the bottom and the youngest on the top. The geologic feature which cuts through another is the younger of the two features. Unconformity- If the sedimentation process is suspended by the emergence of an area from below the water level, no sediment will be deposited and an erosion surface will develop. This gap in the geologic column is called an unconformity. An unconformity is typically shown in cross section by a wavy line. volcanic ash erosion surface limestone IM sandstone matite erosion surface slate granite ANNTH granite Figure 2.3: Cross-section of rock strata
Geologic Time Scale Years Before Present System & Period Series & Epoch Some Distinctive Features 11,000 Modern man. U Quarternary Plestocene Early mars northern glaciation 2 to 2 million 13+1 million Pliocene Miocene Oligocene Eocene Paleocene Large carnivores First abundant grazing mammals Large running mammal Many modern types of mammals First placental mammals 25+1 million 36+2 million 58+ 2 million 6.3 + 2 million Z Tertiary First flowering plants; climax of dinosaurs and ammonites, followed by Cretaceous-Tertiary extinction. Cretaceous 135+5 million First bird, first mammals dinosaurs and ammonites abundant O Jurassic 18+5 million First dinosaurs. Abundant cycads 230+10 million and conifers. Triassic Extinction of most kinds of marine animals, including trilobites Southern glaciation. Great coal forests, conifers Permian 280+ 10 million PennsylvanianFirst reptiles 10 10 million O Carboniferous Sharks and amphibians abundant Mississippian Large and numerous scale trees and 345+10 million seed ferns First amphibians; ammonites; fishes abundant. First terrestrial plants and animals. 425+10 million First fishes; invertebrates dominant. 500+ 10 million First abundant record of marine life trilobites dominant. Devonian 405 +10 million Silurian- Ordovician Cambrian 600+50 million Fossils extremely rare, consisting of primitive aquatic plants. Evidence of glaciation. Oldest dated algae, over 2,600 million years; oldest dated meteorites 4,500 million years Precambrian
How can Age be Determined? Radioactive dating yields more precise estimates of age. Itis based upon the decay of radioactive isotopes such as potassium, uranium, rubidium, and carbon. For the most part this can only with igneous rocks formed from molten lava. be done Table 2.1: Half-life of various parent isotopes. Half-life Isotope Parent Daughter Carbon 14 Nitrogen 14 Potassium 40 Argon 40 Rubidium 87 Strontium 87 Uranium 238 Lead 206 Uranium 235 Lead 207 Useful range of parent years) 5,720 (years) 100-30,000 100,000 4.5 billion 1.3 billion 10 million 4.5 billiorn 47 billion 4.5 billion 710 million hundreds of millions to 15 billion years 10 million to 4.5 billion years In Table 2.1 the parent isotope is the original material and the daughter isotope is the material into which it will decay. The half-life is a measure of how long it takes one half of the material to change. By knowing the half-life, an estimate can be made as to the age of the material. For example,if one kilogram of Uranium-235 has gone through one half-life (710 million years), then there should be 0.5 kg of Uranium-235 and 0.5 kg of the daughter isotope, Lead 207 If the rock strata have both sedimentary layers and igneous features, a combination of both relative and radioactive dating can be used.
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