Shelburne took his place, brew in hand. “Fat city?”
I said, “The jackpot.”
“Now you’re speaking my language.”
I switched to my own. “That pebble is chiastolite hornfels, which…”
“What does that mean?”
“Chiastolite from the Greek khiastos, meaning a cross. Hornfels from the German, meaning horn rock, because it’s flinty and sharp-edged.”
“The names aside — what does it mean for our search?”
I took a careful sip of steaming coffee. A celebration in honor of the coolness of geological names.
Shelburne drummed his fingers on his coffee mug.
I said, “It narrows the neighborhood. Let’s start with the hornfels pebble. Notice the edges are still angular. That means it was not transported far from its source. If a stream had carried and battered it, the edges would be rounded. But they’re angular and that tells us the source was a nearby hornfels zone.”
“How do we find that?”
“Hornfels is very site specific — it’s not all over the place.”
Shelburne glanced at Walter at the map cabinet. “Meaning look at a map?”
“To begin with. But hornfels zones can be small, and not always mapped.”
“So we could be shit-out-of-luck?”
“Not necessarily. We can look for the birthplace. Hornfels gets born when a dike of hot magma intrudes sedimentary rock — call that the parent rock. The dike cooks the parent rock, metamorphosing it. And then the magma cools and hardens into igneous rock. In our case, that’s probably an igneous rock called diorite, since we have diorite in the specimen.”
I paused to give Shelburne the chance to look at the diorite cobbles in the ore. He didn’t bother.
He said, “What about the cross?”
“That’s a gift. That tells us the nature of the parent rock. The chiastolite is a carbon inclusion, which suggests that the parent rock contained organic matter which became the carbon. So that parent rock is likely a carbonaceous slate that got cooked into chiastolite hornfels when the magma intruded.”
“Could Henry have figured that out?”
“You said he’s an amateur geologist.”
“He’s also a romantic. He’d follow that cross and call himself a crusader.”
“You want romance?” I set down my coffee and cupped my hands. “Here’s the metamorphic contact zone: rings around the intrusive dike. The outer ring is the slate. The inner ring, more cooked, is the hornfels. So I can freaking well say that we’re looking for a contact of diorite and slate. If we’re lucky we’ll find the inner ring — the hornfels aureole sheathing the dike.” I picked up my coffee. “There’s romance for you. Geology gets downright sexy.”
Shelburne winked. “You put on a good dog-and-pony show.”
“It’s not…”
“It’s a compliment.”
I shrugged. It was really more of a petrology-and-geochemistry show, but never mind.
“Yoo hoo!” Walter called, from the table beside the map cabinet. “Come on over and let’s see where we are.”
I trailed Robert Shelburne to the map table. Along the way he detoured to the kitchen sink and dumped his coffee, whispering to me, “Can’t stand the stuff.”
I didn’t know what to think of that. Of him. He’s considerate of Walter’s need for the coffee ceremony. Unwilling to decline the offer. Unwilling to drink the stuff. Willing to let me in on it. I didn’t know what to think.
We flanked Walter. He was hunched, hands pinning a map to the table. It was a geologic map of the gold country, with lithologic pattern symbols showing the major rock units. Walter’s crosshatched hands were weathered symbols in and of themselves. Walter’s a seasoned pro, with rocks and clients. If he’d noticed the coffee dump, he ignored it. If he’d paid mind to the dog-and-pony comment, he didn’t mention it. He lifted a hand, patted my arm. Don’t take it to heart.
I hadn’t.
“This is the Mother Lode,” Walter said. “It’s roughly three hundred square miles. If we narrow that to likely hornfels neighborhoods, we’re looking at many dozens of square miles.”
“I can do better than that,” Shelburne said.
Walter looked up, from map to client.
“I can narrow the neighborhood down to about twenty square miles.” Shelburne ran his finger across a slice of the gold belt. “That’s where my father searched. That’s where he dragged Henry and me searching. What you need to do is figure out where in the ‘hood this rock came from. That’s where Henry will be searching.”
“Then we’ll want a larger-scale map.” Walter moved to the map cabinet. “Meanwhile, help yourself to more coffee, Mr. Shelburne. We have donuts, as well.”
The coffee ceremony was history, I saw. Donuts now. Walter had just welcomed Robert Shelburne onto the team.
Shelburne threw me a wink and said to Walter, “You have any glazed?”
Walter and I spent the remainder of the day on more sophisticated analysis, while Robert Shelburne went out for a long lunch and last-minute errands. Normally we would have spent more time on the labwork but Henry Shelburne set our timetable.
Find Henry before he finds the source. Hunt for the source to find Henry.
Out there in the wild. Missing. Looking like the Henry in the photo because I could not conjure up an alternative. Squint-eyed, on some mission, suicidal or not. In need of finding, or not.
Either way, we’d signed on to find him.
5
The following day we left at dawn, taking Shelburne’s pricey Land Rover.
We had to cross the spine of the Sierra Nevada range, traveling from the austere eastern side to the lush western flank, deep into gold country, deep into the heart of the Mother Lode.
Walter, in the back seat, was re-reading Waldemar Lindgren’s Tertiary Gravels of the Sierra Nevada of California. I’d never read it but I knew it was a classic. An original copy would fetch a price in the hundreds. This morning I’d asked what Walter was downloading to his tablet. He’d said, “The bible of the deep blue lead.”
That took me aback. I’d thought he used his tablet strictly for online research or sharing docs with colleagues on the other side of the world. But books? He read his books on paper — biographies, poetry, and mysteries, from the current crop all the way back to Sherlock because, he liked to point out, Sherlock Holmes was the first forensic geologist. As for technical books, he owned a worn paperback of Lindgren that would have served him perfectly well in the field. Instead, he was reading the freaking bible of the deep blue lead in pixels?
I’d said, “Since when did you start reading your books in pixels?”
“Since I looked in the mirror and saw an old man.”
“You’re not old,” I’d said firmly. “You’re just an ink-and-paper man.”
“Old dog can’t learn new tricks?”
And now, as I rode shotgun in Shelburne’s Rover, I could not help glancing into the side-view mirror, spying on Walter in the back seat. Hair grayer than when I’d last paid attention?
Funny thing: Walter had looked old to me when I first met him. I was eleven and he was in his forties. To a kid, that was old. Over the following years as I worked in the lab — part-time after school and full-time in the summers — the only aging I paid attention to was my own, particularly when I crashed into my teens. Then, during my college years, I would come home for the summers and grace the lab with my learning, spouting textbook tidbits like they were tweets. During that stretch I didn’t notice either of us aging. I was too busy proving myself. By the time I’d completed grad school and took my book-learning back into the field what I finally noticed was the authenticity of Walter’s skills.