Asked by teh
Temperature of the earths crust
All Answers 1
Answered by
GPT-5 mini
AI
Do you mean the temperature as a function of depth in the Earth’s crust? Here are the key facts and typical values:
- Geothermal gradient (how temperature rises with depth): typically about 20–30 °C per kilometer in ordinary continental crust. Gradients can be much lower (≈5–10 °C/km) in cold, stable cratons and much higher (40–100+ °C/km) in rift zones, volcanic areas and near intrusions.
- Surface (0 km): roughly ambient surface temperature (−20 to +40 °C depending on climate; commonly taken ≈10–20 °C for simple estimates).
- Shallow depths (examples using 25 °C/km):
- 1 km: ~25 °C above surface (~35–45 °C total)
- 3 km: ~75 °C above surface (≈85–95 °C)
- 5 km: ~125 °C above surface (≈135–145 °C)
- Mid-to-deep crust:
- At typical continental crust thickness (≈30–40 km) temperatures at the Moho (crust‑mantle boundary) are commonly in the few hundred to ~800–900 °C range, depending on gradient and crust thickness.
- Oceanic crust is thinner (≈5–10 km); temperatures at its base are lower in old oceanic lithosphere but are much higher near mid‑ocean ridges.
- Mantle and deeper: temperatures continue to rise; the upper mantle reaches ~1,000–1,400 °C at depths of a few tens of kilometers to a couple hundred kilometers, and several thousand degrees nearer the core.
- Heat flow: surface geothermal heat flux averages on the order of 50–100 mW/m², higher in tectonically active regions.
Factors that control crustal temperature: heat flow from the mantle and radioactive decay in crustal rocks, thermal conductivity of rocks, tectonic setting (rifts, subduction zones, intrusions), and hydrothermal circulation.
If you want, I can:
- compute temperature at a particular depth using a chosen gradient,
- give typical temperatures for a specific region or tectonic setting,
- or show a plot/table of temperature vs. depth for several gradient values.
- Geothermal gradient (how temperature rises with depth): typically about 20–30 °C per kilometer in ordinary continental crust. Gradients can be much lower (≈5–10 °C/km) in cold, stable cratons and much higher (40–100+ °C/km) in rift zones, volcanic areas and near intrusions.
- Surface (0 km): roughly ambient surface temperature (−20 to +40 °C depending on climate; commonly taken ≈10–20 °C for simple estimates).
- Shallow depths (examples using 25 °C/km):
- 1 km: ~25 °C above surface (~35–45 °C total)
- 3 km: ~75 °C above surface (≈85–95 °C)
- 5 km: ~125 °C above surface (≈135–145 °C)
- Mid-to-deep crust:
- At typical continental crust thickness (≈30–40 km) temperatures at the Moho (crust‑mantle boundary) are commonly in the few hundred to ~800–900 °C range, depending on gradient and crust thickness.
- Oceanic crust is thinner (≈5–10 km); temperatures at its base are lower in old oceanic lithosphere but are much higher near mid‑ocean ridges.
- Mantle and deeper: temperatures continue to rise; the upper mantle reaches ~1,000–1,400 °C at depths of a few tens of kilometers to a couple hundred kilometers, and several thousand degrees nearer the core.
- Heat flow: surface geothermal heat flux averages on the order of 50–100 mW/m², higher in tectonically active regions.
Factors that control crustal temperature: heat flow from the mantle and radioactive decay in crustal rocks, thermal conductivity of rocks, tectonic setting (rifts, subduction zones, intrusions), and hydrothermal circulation.
If you want, I can:
- compute temperature at a particular depth using a chosen gradient,
- give typical temperatures for a specific region or tectonic setting,
- or show a plot/table of temperature vs. depth for several gradient values.
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.