The Backyard Science group regularly features the Daily Bucket. Tomatoes ripening? Pears dropping? Yellow jackets getting surly? Please add your own observations in a comment. Insects, weather, meteorites, climate, birds, and more are all worthy additions to the Bucket. Include, as close as is comfortable for you, your location. Your impressions will provide additional viewpoints of the life around us.
I've always considered Phoenix, Arizona to be a outpost of the first circle of Hell. It had gotten over 120 degrees a few times, and routinely exceeds 100 for 90 days every year. Too many roads are pool-table-level 10 mile stretches of desultory 1 and 2 story retail establishments; tire store, smoke shop, tattoo parlor, Goodwill, and so on. The controversial Joe Arpaio is the sheriff for the surrounding county.
However, when I was there last weekend, for the first time I stumbled onto some of Phoenix's unique geology. Not too many cities can feature a chain of volcano cones that poke into the sky from the suburbs to downtown and on to the other edge of town. Rome may have seven hills, but Phoenix has 12 extinct volcanoes.
That's Lookout Mountain, north of downtown, and part of the Phoenix Mountain Preserve. The Phoenix Mountains arc for 8 miles across urban and suburban neighborhoods.
The Mountains' story began 1.7 billion years ago, when Arizona was under an ocean. Fierce volcanic pressures forced these lava-spewing cones to rise from the ocean floor. Perhaps the cone tips formed a chain of small islands at one time. The constant eruptions, over millions of years, eventually filled a portion of the ocean basin, converting the area into a delta or floodplain.
The millions of years of volcanoes spouting sulfur, fire, and brimstone, all spilling into a steaming ocean would have provided a hellish vision, although the only witnesses for millennia would have been, at best, algae-like organisms.
The volcanic uplifts pushed aside and distorted what would have been the orderly layered sediments of an old ocean floor. Here's what the rocks look like at a road cut through North Mountain.
I was expecting horizonal layers of grey shale, but instead there are near vertical stands of mica-like glittering plates.
After the ocean receded from these mountains, time and chance happened to them all, along with wind and rain. The angle of repose once formed their neat cones. But those eroded, leaving behind, in some cases, abrupt plugs of what must be the hardest lava flows that protruded from the mountain tops. Lookout Mountain sprouted more recently, a mere 25-odd million years ago.
Many critters and neat plants occupy this rugged preserve. I saw Anna's hummingbirds, a roadrunner, chipmunk-sized squirrels, and a cottontail rabbit, and tore a shirt trying to retrieve a a golf ball from a sharp-branched mesquite grove at the base of the preserve.
Phoenix only averages 8 inches of rain annually, including about 1.4 inches in both January and August. The desert plants and animals must blossom and mature swiftly to take advantage of any brief rainfalls. The entire August rain will sometimes pelt down in just an hour or two.
Here's some links with pretty plant and critter pictures and lists, and then actual geologic narrative. Pretty plants first:
http://www.arizonensis.org/...
now dense scientific language;
http://repository.azgs.az.gov/...
That's a small part of Phoenix's geologic history. What's going on in your area? I'll be gone for a couple of hours but will be back mid-morning, Ecotopia time.
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