hardpan

American  

[hahrd-pan] / ˈhɑrdˌpæn /

noun

1. any layer of firm detrital matter, as of clay, underlying soft soil.

2. hard, hard, unbroken ground.

3. the fundamental or basic aspect of anything; solid foundation; underlying reality.

   the hardpan of mathematical theory.

---

hardpan British  

/ ˈhɑːdˌpæn /

noun

1. a hard impervious layer of clay below the soil, resistant to drainage and root growth

---

hardpan Scientific  

/ härd′păn′ /

1. A hard, usually clay-rich layer of soil lying at or just below the ground surface, in which soil particles are cemented together by silica, iron oxide, calcium carbonate, or organic matter that has precipitated from water percolating through the soil. Hardpans do not soften when exposed to water.

2. Also called caliche

---

Etymology

Origin of hardpan

An Americanism dating back to 1810–20; hard + pan ¹

Example Sentences

But collectively, we’re mining an irreplaceable commons that our grandchildren will inherit as hardpan.

From Salon

Mike McCormack lives in Galway, Ireland, on a seacoast facing the Atlantic with rocky, unforgiving cliffs that give way to thin, hardpan soil.

From Los Angeles Times

He envisions a world where neighbors grow food to share with each other and those hardpan vacant lots and parkway strips between sidewalk and street are lush with birdsong, flowers and food-producing plants.

From Los Angeles Times

The hardpan streets had cuttingly sharp edges, but they also glinted with mica, which as a kid struck me like treasure — if you could dig it out, wouldn’t it be silver dust?

From Washington Post

Previously, gardeners used rototillers, which would produce a fluffy soil on top but, after 50 years of tilling, created a hardpan clay beneath.

From Washington Post