Glacial Features and Cycles

Glacial Features

• Glacier: A large, slow-moving mass of ice formed from compacted snow.
• Ice Sheet: A massive glacier covering a large land area (larger than a glacier, >50,000 sq km).
• Glacial Period: A time when glaciers expand significantly.
• Ice Age: A period with extensive ice sheets and glaciers.
• Glacial Advance: Glaciers growing and spreading.
• Glacial Retreat: Glaciers shrinking and moving back.
• Interglacial Period: Warmer periods between glacial periods, with ice sheet retreat.
• Paleoclimate: The study of past climates, including glacial and interglacial periods.
• Milankovitch Cycles: Cyclical changes in Earth's orbit impacting climate over thousands of years.
• Solar Insolation: The amount of solar energy Earth receives, affected by Milankovitch Cycles.
• Glacial-Interglacial Cycles: Recurring ice sheet advances and retreats, driven partly by Milankovitch cycles.
• Ice-Albedo Effect: Ice reflects solar radiation, cooling Earth; reduced ice cover leads to warming.
• Glacial Maximum: The point during a glacial period when ice sheets are largest.
• Geological Time Scale: A timeline of Earth's history, showing glaciation and interglacial periods.

Prehistoric Eras

• Paleolithic Era (Old Stone Age): From 2.5 million years ago to approximately 10,000 BCE, the earliest and longest human period. Marked by rudimentary stone tools, hunting/gathering, and early human societies.
  • Lower Paleolithic (2.5 million to 300,000 years ago): Earliest Paleolithic; early humans (Homo habilis, Homo erectus) made simple stone tools (e.g., hand axes). Evidence of fire control and early social structures is present.
  • Middle Paleolithic (300,000 to 40,000 years ago): More sophisticated stone tools (Mousterian tool culture); emergence of Homo neanderthalensis and early Homo sapiens; evidence of symbolic behavior and early burials show increasing complexity.
  • Upper Paleolithic (40,000 to 10,000 years ago): Modern humans (Homo sapiens) develop advanced tools, art (cave paintings, carvings), and complex societies. Hunting strategies improved, long-distance trade, and structured dwellings emerged.
• Mesolithic Era (Middle Stone Age): Transitional period between the Paleolithic and Neolithic Eras (10,000-8,000 BCE); gradual shift to early agricultural practices; more specialized tools like microliths common.
• Neolithic Era (New Stone Age): Begins around 10,000 BCE, characterized by agriculture, animal domestication, permanent settlements, advancements in pottery and tool-making leading into social hierarchies and organized communities.

Neolithic Stages

• Neolithic Pre-Pottery Phase (10,000-7,000 BCE): Early settlement and farming; no pottery; stone tools, mud-brick structures; early experimentation with agriculture and animal domestication.
• Neolithic Pottery Phase (7,000-5,000 BCE): Widespread pottery use; pottery for both function and decoration; indication of advances in technology and culture; more complex communities with trade, social stratification, and specialized crafts.