How long would is take for 1300 feet of caliche to build up?
Ah, caliche — the concrete of the desert. If you’re asking how long it would take for **1,300 feet (about 400 meters)** of **caliche** (calcium carbonate–rich hardpan) to accumulate naturally, the answer is: **a *really* long time** — we’re talking **millions to tens of millions of years**.
### Here’s why:
1. **Caliche forms slowly** via precipitation of calcium carbonate from groundwater, especially in arid and semi-arid climates.
2. Typical rates of **caliche buildup** are on the order of:
– **0.01 to 1 mm per year**, depending on climate, vegetation, soil activity, and water movement.
3. Let’s say the max rate is 1 mm/year:
– 1,300 feet = ~396,000 mm
– 396,000 mm ÷ 1 mm/year = **396,000 years (best case)**
– But more realistic? 0.1 mm/year → **~4 million years**
– At 0.01 mm/year? **~40 million years**
### But here’s the kicker:
It’s unlikely that **pure caliche** would accumulate in one vertical column for 1,300 feet. Caliche tends to form in **thin, hard layers** (a few inches to a few feet thick) within soil profiles, not in mile-high stacks. So if you’re finding 1,300 feet of caliche-like material, you’re probably looking at:
– **Multiple geologic layers** where caliche formed episodically
– **Sedimentary rock sequences** with caliche horizons
– Or a **misidentification** — e.g., maybe you’re actually looking at limestone, dolomite, or another carbonate rock that’s been uplifted or exposed
### TL;DR
**1,300 feet of natural caliche** would take **millions to tens of millions of years** to form — and even then, it’s probably not all “caliche” in the strict sense, but a composite of various carbonate-rich deposits over deep geological time.
Want to dig into the geologic setting or speculate wildly about ancient desert oceans? I’m game.
Just looking at southern arizona lands
Ah, Southern Arizona — land of saguaro, sun, and **sedimentary mysteries**. If you’re asking about **1300 feet of caliche-like material** in that region, here’s the dirt (literally):
—
### 🧱 **Realistic Caliche Depth in Southern Arizona**
– **True caliche** (a.k.a. *calcrete*, *hardpan*) in Arizona **rarely exceeds a few meters** thick. Typically:
– Forms in the top **1–6 feet** of soil
– **Max out** around **10–15 feet** in old desert pavements or abandoned alluvial fans
– It’s a **soil horizon**, not a thick geologic formation. So 1,300 feet? Not caliche.
—
### 🏞️ So What *Is* That 1300 Feet?
You’re likely looking at:
– **Sedimentary rock layers** from the **Tertiary and Quaternary** periods (past 2–50 million years)
– These **often contain caliche lenses or horizons** embedded within **alluvial deposits** or **lacustrine beds** (old lakebeds)
– Example: **Bajada deposits** — where gravel, sand, silt, and occasional caliche build up over time in desert basins
—
### ⛏️ Possible Geological Explanation
– The **Basin and Range Province** (which includes southern AZ) underwent major **faulting and sediment accumulation**:
– Valleys filled with **sediment fans** shed from uplifted mountains
– These fans can be **thousands of feet thick**, with **interbedded caliche layers**
– So you might have 1300 feet of **mixed sediment** containing **dozens or hundreds of caliche episodes**, each separated by thousands of years
—
### 🧬 Time Frame
– If you found 1300 ft of **intermittent caliche horizons**, that likely records **tens of millions of years** of:
– Climate cycling (wet/dry)
– Soil formation and burial
– Groundwater migration
A well core or stratigraphic column in that area might tell a **5–30 million year story**, give or take erosion and tectonics.
—
### Bottom Line:
– You’re **not** looking at a single massive caliche slab.
– You’re likely dealing with a **deep sedimentary basin** with **intermittent caliche** episodes—**a long, episodic geological diary** from the Miocene to now.
– That 1300 ft probably **took 10–30 million years** to accumulate.
Wanna play geologist and map it out by age and formation? I can help pull up strat columns from the region.