I was watching our local pbs station last night (mostly between innings of the All Star Game), and there was a feature on about asteroid and comet impacts. I believe they said the asteroid that created meteor crater in Arizona was about 60 meters in diameter and the impact occurred about 50,000 years ago. They continued that impacts with a asteroid of that diameter statistically should occur every 2,000 years. [I believe I heard that correctly - someone correct me if I'm wrong.]

That means, statistically, there should have been about 25 such impacts since the one which created meteor crater. You would assume 4/5ths of those impacts would be in the oceans or other water bodies, but then that means there should have been 4 or 5 land impacts over that period of time.

Is there any evidence of any such land impacts over the last 50,000 years?

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That frequency matches up roughly with values from

Quantifying the Risk Posed by Potential Earth Impacts

Some bodies of this size will break up in the Earth's atmosphere and pretty much disappear before they reach the ground, like the Tunguska body did in 1908. The Meteor Crater body was unusual because it did not break up; it is likely that it was an iron-nickel asteroid. These are less common than the stony meteorites, but have higher internal strength and so are more likely to survive a trip through the Earth's atmosphere.

So, perhaps the answer to your question is that most of the 50-meter bodies over the past few thousand years have been stony objects, and have created airbursts which leave little long-lasting damage on the ground below.

I thought I read that Barringer Crater is well preserved because of Arizona's arid climate. Maybe its age-cohort crater members have washed away much in their locations' rains and/or been covered by their locations' rich flora. I'd expect they'd be known about, just maybe not famously obvious.

Like this: University of Arizona: Barringer Meteor Crater and Its Environmental Effects

If there are only a handful of expected craters of that age that might be said to be missing, reduced in number by the StupendousMan's estimate of air-bursts, then it doesn't seem much of a statistical mystery.

Wikipedia has a list of notable impact craters on Earth, ending with recent ones:

More perplexing to me: why the large gap between the several ones 5-15 million years ago and the 3 about 50000 years ago? Where are the 100000-year-old craters? The 200000-year-old, the 300000? It sorta looks like those little guys just don't get found, unless they are fairly recent.

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There was some discussion of there having been a Tunguska-like airburst over the southern Dead Sea a thousand or more years BC.

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Barringer crater is relatively well-preserved due to it's dry environment which minimizes erosion due to rain. By comparison, impacts into ice, softer soils, or areas where the water table is near the surface, such as Florida, might escape notice altogether.

There is one lake that I know of in Florida that's almost perfectly round, about a mile across, and it's bottom is entirely of sand, and concave, with a gentle slope towards the middle, which is around 250 to 300 ft deep.

The lake is spring fed, with only one small creek as it's outflow.

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Whoever says "perception is reality" is daft. It's merely an abstraction, and often not a very good one.

Hmmmm, if so, it would be well documented in the historical texts of the time and area.

1000 BC sounds absurdly archaic to most people, but it actually isn't. There is a plethora of documents from that era, divided up between several cultures (Egypt, the Levant, Babylon, Assyria, etc.). The Dead Sea is smack dab in the middle of the commerce routes and was an important area. If something like Tunguska had happened there anytime in the 2nd or 1st millenium (i.e. BC), we would definitely know about it.

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