Last Minute Lecture

Landscapes & the Hydrologic Cycle – How Earth’s Surface Evolves | Interlude F from Earth: Portrait of a Planet What gives the world its valleys, mountains, canyons, beaches, and ever-changing terrain? In Interlude F of Earth: Portrait of a Planet , Stephen Marshak explores the powerful geologic forces and the endless movement of water that sculpt Earth’s dynamic surface. Watch the chapter summary on YouTube or dive into the full blog breakdown below! What Is a Landscape? Landscape: The overall shape, character, and arrangement of a region’s land surface, made up of individual landforms (valleys, cliffs, mesas, terraces, beaches, and more). Topography & Relief: Differences in elevation are measured as relief, visualized with contour lines and digital elevation models (DEMs). How Do Landscapes Form and Change? Uplift: Vertical movement of Earth’s surface caused by crustal thickening, lithospheric heating, isostatic rebound (post-glacial or post-erosion),...

Sediments and Soils Explained — Weathering, Soil Horizons, and Earth's Surface Veneer | Interlude B from Earth: Portrait of a Planet What lies between solid rock and the air we breathe? In Interlude B of Earth: Portrait of a Planet , Stephen Marshak examines sediments and soils—the thin but crucial layer covering Earth’s surface. These materials are the products of weathering and biological processes, forming the foundation for terrestrial ecosystems and agriculture. For a concise visual summary, watch the chapter video on YouTube , or read on for a full breakdown of this key geological topic. The Formation of Sediments and Soil Physical Weathering: Rocks are broken down by frost wedging, root growth, salt crystal formation, jointing, and exfoliation. These processes create clasts (rock fragments) that accumulate as sediment. Chemical Weathering: Water, acids, and oxygen react with minerals to cause dissolution, oxidation (rusting), hydrolysis (breaking down feldsp...