E. SCIE

• Weathering


  1. Rock and mineral breakdown or dissolution on Earth's surface

  2. Gradual turning of solid rock into sediments

  
• Types of Weathering


  • Physical/Mechanical Weathering
  • Chemical Weathering
  • Biological Weathering
• Physical/Mechanical Weathering


  • Involves breaking down a rock's physical structure
  • Caused by factors like rain, wind, or other atmospheric conditions
• Physical/Mechanical Weathering processes


  • Water and Wind Abrasion
  • Frost and Salt Wedging
  • Unloading and Exfoliation
• Chemical Weathering


  • Involves breaking down the rock to its molecular chemical components
• Biological Weathering


  • Involves the breaking down of the rock caused by the action of living organisms
• Erosion


  1. Sediment transportation from one area to another

  2. Caused by natural forces like wind, water, glaciers, and gravity
• Deposition


  Eroded sediments settling in a new place

  
• Compaction


  1. Reduction in a fixed mass of sediment's volume

  2. Compression of sediments over time to reduce the space between them
• Cementation


  Binding of compacted sediments by mineral matter precipitating in the small spaces
• Relative Dating


  • Comparing the ages of two different materials to know their relative order
  • Assigns the timescale that the rock belongs to without finding its specific age
• Principle of Superposition


  • In an undisturbed sequence of sedimentary rock layers, the oldest rocks are at the bottom and the youngest rocks are at the top

  
• Principle of Original Horizontality


  • Sedimentary layers of rock are originally deposited in horizontal layers

  
• Principle of Cross-Cutting Relationships


  • If one geologic feature cuts across another, the feature that cuts across is younger
• Principle of Faunal Succession


  • Fossil organisms succeed one another in a definite and determinable order, allowing recognition of time periods by their fossil content

  
• Unconformities


  Gaps in the geological record where layers of rock are missing due to erosion, non-deposition, or deformation

  
• Angular Unconformity


  Younger sediments rest upon the eroded surface of tilted or folded older rocks, showing an angular relationship
• Disconformity


  Break in the sedimentary rock sequence where parallel layers are separated by erosion, but the layers above and below are parallel

  
• Nonconformity


  Sedimentary rock rests on top of igneous or metamorphic rock, indicating a period of uplift and erosion before deposition

  
• Stratigraphy


  Assumes the lowest layer is the oldest and the topmost layer is the youngest
• Biostratigraphy


  Uses faunal deposits like fossils to establish a dating strategy, an extended version of stratigraphy
• Cross dating


  Compares fossils of one layer with another layer of known dating, following the principle of Cross-Cutting Relationships
• Absolute Dating


  Technique that determines the exact numerical age of a historical remaining, also called numerical dating
• Methods of Absolute Dating


  • Radiometric dating
  • Amino acid dating
  • Dendrochronology
  • Thermoluminescence
• Significance of Absolute Dating


  • Provides numerical ages with high precision
  • Enables global correlation of strata and evolutionary/climate studies
  • Supports resource exploration and archaeological dating
• Relative Dating vs Absolute Dating


  Relative dating determines the order of events, absolute dating provides numerical ages
• Relative dating involves determining the age of a rock or fossil by comparing it to other rocks or fossils, using principles like superposition, original horizontality, cross-cutting relationships, and faunal succession
• Absolute dating provides a numerical age for a rock or fossil
• Rock dating is important to construct a timeline of Earth's past events, trace the evolution of life forms, assess environmental hazards, and understand human history and cultural evolution

  
• Index Fossils


  Preserved forms of life that existed during a certain and limited period in the planet's geological timeline, often used to guide the age of rocks
• Archaeology


  • Helps build a better picture of how humans lived in the past
  • Helps understand how humanity, culture, and societies evolved
• Object of material culture


  Knowing the age, how it was made, and the surroundings in which it was found helps classical, historical, or ethno-archaeologists to better hypothesize the purpose or cultural meaning that might have been attributed to it in the past
• Index Fossils


  • Preserved forms of life that existed during a certain and limited period in the planet's geological timeline
  • Most are formed through permineralization
• Index Fossils


  • ammonites
  • trilobites
  • graptolites
• Index Fossils


  • Typically distinctive, and abundant, and have a short geologic range, meaning they lived for a relatively brief period
  • Useful for dating rock layers and correlating strata across different locations because they provide a marker or reference point for the age of the rock in which they are found
• Geologic Time


  The extensive interval of time occupied by the geologic history of Earth

  
• Major divisions of the Geological Time Scale


  • Precambrian
  • Paleozoic
  • Mesozoic
  • Cenozoic

  
• Precambrian Era


  • The geological time before the Cambrian period, the first period of the Phanerozoic Eon
  • The diversity of life and evolution started in the Cambrian period, which was 542 million years ago
  • Huge objects, the crust, bombarded the Precambrian Earth, separated into the first continents and ocean basins, crustal plates mobilized, the atmosphere transitioned from reducing to oxidizing, and early life originated and evolved
  • The Precambrian era created the physical, chemical, and organic parameters for the feasible foundation of life on Earth
  • The Precambrian is the earliest part of Earth's history,4,600 million years ago
  • The Precambrian accounts for 88% of the Earth's geologic time
• Origin of Life


  • The earliest known life arose during the Pre-Cambrian Era
  • All of this life existed in the world's oceans
  • The earliest life consisted of bacteria that were able to extract nutrition from chemicals in seawater
  • Primitive life forms lived during the Precambrian era
  • The oldest bacteria fossils were observed in the Archean eon rocks
• Evolution of Earth


  • The solar system and planets were formed first, during the Precambrian period
  • During the 4,000 million years that this time lasted, Earth became physically, chemically, and biologically habitable
  • The earliest life forms appeared, and their evolution began around the end of the Precambrian epoch