Atomic Number = number of protons Atomic number determines an atoms identity H=1, Mg=12, O=8, Fe=26 4. Percentage of parent atoms that decay in each half life is the same (50%) The actual number of atoms that decay with each passing half-life continually decreases I.
Atomic Mass = protons + neutrons Can change in different atoms of the same element 5. Principles of Numerical Dating Increase in daughter = decrease in parent I.
The DECAY RATE is constant and acts like a “clock”. Carbon 14 (radiocarbon dating) Anything living takes in carbon in the form of CO2 (stable and unstable) by eating and drinking and photosynthesis As long as the organism is living, it is taking in more 14C but when it dies, it’s 14C starts declining (12C remains constant) Longer time since it died less 14C I. Other Dating Techniques: Besides isotopic methods A.Decay rates are not affected by temperature, pressure, or chemical reaction with the parent isotope. Sources of Error Groundwater can bring in new ions and carry old ions away Sample unfractured and unweatheredrock, makes the age of the rock too young) Very young rocks: not enough time to accumulate daughter isotopes to be measured accurately So we date many different samples and make sure the ages agree We date using different dating methods to make sure they agree II. Carbon 14 (radiocarbon dating) 14C 14N 5730 year ½ life Useful between 100 and about 50,000 years old Can date things that contain organic carbon (Used to be living): bones, shells, wood, charcoal, plants, paper, cloth, pollen, seeds) I. Dendrochronology (Tree-ring dating) Trees grow rings for each year We can count rings to get ages of trees Pronounced changes in climate (i.e.By measuring the ratio of parent to daughter isotopes in the mineral and comparing it with the rate of radioactive decay, we can determine the numerical age of a rock. Types of Isotope Dating We pick dating methods based on approximate age of the rock and the rock composition Old rocks – long half lives Young rocks – short half lives Composition: have to use a dating method corresponding to what is in the rock I. drought) causes distinct patterns that can then be correlated between trees Useful for dating: landslides, avalanches, or mudflows or wooden artifacts I. Other Dating Techniques: Besides isotopic methods A.Unfortunately, the page you were looking for no longer exists.We are currently working on a new website that will update many of our older web pages.
See our current news blog: Digging the Fossil Record Also check out our plans for our Deep Time exhibit hall, to open in 2019 And check out the links on the side bar to the left.Limestone layers form in flat layers at the bottom of a shallow sea. These gray layers of limestone are exposed in the Mojave Desert, pointing up at an angle from the flat desert floor. Charge: Protons + Neutrons (neutral) Electrons - Atoms always have the same # of protons and electrons so the charge is balanced. Mass: Protons 1 AMUor atomic mass unit = 1.67x10-24 gms Neutrons = 1 AMU Electrons = mass negligible I. Isotope Dating: based on the rate of decay of radioactive isotopes within rocks 3. Half Life: time it takes for half the atoms of the parent isotope to decay, ranges from tens of billions of years to thousandths of a second. Review – Relative Dating Principle of Original Horizontality Principle of Superposition Principle of Cross-Cutting Relationships Inclusions Principle of Faunal Successions. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. Principles of Relative Dating Review – Relative Dating Principle of Original Horizontality Principle of Superposition Principle of Cross-Cutting Relationships Inclusions Principle of Faunal Successions I. Isotope Dating: based on the rate of decay of radioactive isotopes within rocks 1. Numerical Dating An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.