One of the first rocks I learned, hot ridges in the Trinities,
a magnesium silicate, like talc–the pale green outcrops
marked by the deep green waxy leaves of yerba santa,
indicator specie: I could find either one by the other.
Broken chunks with smooth glassy surfaces,
like a calm ocean, sub-vitreous, sometimes called “greasy,”
cream green, black, leaf green, blue, yellow, mottled
“like the skin of a snake.”
Called ultramafic now, on the old maps, “ultrabasic,”
mapped as dark purple north south bands
snaking through the Franciscan, the Sierra, and the Klamaths.
I’d seek them out, looking for soapstone,
and usually found some, once, near a wall of red chert,
where the serpentine weathered and gullied. I dug with a pick.
Another deposit near Tangle Blue Lake, the soapstone black;
carved a pipe for a friend.
An alteration mineral, “second-growth,”
said to be mantle rock touched by the sea, mid-ocean rifts,
beneath basalt blobs and pillows, sheeted dikes and gabbro,
peridotite -> serpentine;
thus serpentines mark ophiolites–
plate subduction, abyssal rocks scraped off, shoved up, or a collision:
an island archipelago floating across the ocean on a tropical cruise.
Ophis: sea serpent, dragon, water-snake,
Illuyanka, “serpentine snake”, or “eel,”
tendril turn, pushing on itself, string-knot.
Serpentine outcrops mostly barren, Eriodictyon
an exception, or sometimes Salvia sonomensis,
smelled before seen (I called it “camphor sage”).
Too many metals for most plants: iron, nickel, chromium,
ionic radii like magnesium (seventy-five picometers),
replacing it and forming deposits.
Often sandwiched by gabbro—and intergrading—
dark pyroxenes, olivine, heavy silicates,
thrust upon whatever is around—old sediments,
metamorphosed, quartzite, slate, or a hornblende schist,
the serpentine slippery, slick-sliding up like a watermelon seed.
At 15x magnification, the glassy chips are often striated:
lines and streaks on the smooth rolls of a glassy ocean,
maybe like glacial scratches on a polished granite wall.
Sometimes lamellar, antigorite, or with overlapping scales
that look like Anasazi cliff dwellings: lizardite.
One piece with tiny white specks, each one blurry and
with a white fuzzy tail, comets, like snow banners
from Himalayan peaks, blown by some gradient wind.
The magnesium formed by carbon burning:
12C + 12C -> 24Mg + γ
The high Coulomb barrier of the nuclei requires
a big star, over four solar masses, and a billion degrees Kelvin:
a red giant, in maturity, hydrogen and helium already burnt,
ready to retire, or supernova. Magnesium silicates
eighty percent of the earth’s mantle, ninety with iron: peridotite–
the earth’s most common rock—surprisingly rare
at the surface, but thought
I’d go find some.
I sampled edges of wide serpentine belts,
near massive gabbros and diabase sills.
First trip sought an outcrop mapped fifty years before by Olmsted,
Flagstaff Hill near Folsom Lake, at Pilot Hill
stopped by private roads and a gate: “enter code.”
Terrane collision. Mesozoic squabble.
Felsic plutons around us, come up like bubbles.
Found one rock with fibrous chrysotile in a thin vein: “asbestos,”
another with a single serpentine sliver, a millimeter wide,
creamy green muscling in, tiny stacked layers,
white at the tips, powdery black below,
glassy green grains in the matrix, conchoidal, maybe olivine.
“So much depends on”
the sexual nature of silicon:
olivine like the nuclear family, fire-born tetrahedrons,
linking up, when they can, a conga dance of pyroxene,
or double-linked, amphibole, hornblende layers and planes
that flash in the light. Or, pressured, honey-comb sheets
of biotite. With three axes it’s feldspar, and floats to the top.
The alteration reactions highly exothermic,
fingers of serpentine expand and engorge,
ejaculate protons—thought by some the free lunch
feeding the first life borne at deep sea vents.
Like silicon, carbon is polymorphous, chains up,
two siblings, neither sure of their gender.
Plants grabbed the magnesium, red-blooded
critters the iron. (Mollusks took copper: hemolymph.)
The olivine seems to go first,
3Mg2SiO4 + SiO2 + 4 H2O -> 2Mg3Si2O5(OH)4
Olivine + silica + water -> serpentine
3Mg2SiO4 + 3H2O -> 2Mg3Si2O5(OH)4 + Mg(OH)2
Olivine + water -> serpentine + brucite
Pyroxene holds out, other reactions complicated, some reversible,
a fine mess of color and pattern and host rock,
green minerals with long names, talc going both directions.
Serpentine from peridotite, serpentine from basalt,
serpentine from gabbro–one needs a petrologist with a good lab.
On the Feather, mining road above the river,
saw the sinusoidal track of a rattler in the dirt:
upon thy belly shalt thou go, and dust shalt thou eat.
In samples the olivine gone soft, scratchable,
serpentinized, with chunks of pyroxene like charcoal, hornblende–
gabbro, first to leave the nest.
From the Feather crossed a gap, fifty miles of Cascade volcanoes:
Lassen, Shasta, to the Trinity ophiolite,
Ordovician: mollusks, first nautiloids, scorpions.
At 9000 feet, steep slope of Mt. Eddy,
found a tumble of rust-covered warty boulders
spilling from the mountain, some with a half-inch crust,
serpentine, as if they’d been dipped and fried.
Serpent is earth god, or goddess, Tiamat, chaos-born—
a problem for city gods bent on empire:
Typhon, Yahweh, Marduk: dragon-slayers.
In Revelations: drakon, ophis, diabolos, satanus,
all in the same verse.
Broke a hefty chunk with a hammer (“merciless club”),
and inside, the green scales:
dreamt I cut her up—
buried pieces of intestines,
green skin, black heart, in different holes;
then dreamt I was a person was supposed to remember that.
Tiamat, the shining face of the deep, tehhom,
second verse of Genesis, Tethys Sea,
ti ama: life mother,
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