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fired back, "happens to be the single biggest contributor to geologic change on our planet. A little something called a metamorphic rock? Geology 101?"

Corky scowled.

Tolland realized Xavia had a point. Although heat did play a role in some of earth's metamorphic geology, most metamorphic rocks were formed by extreme pressure. Incredibly, rocks deep in the earth's crust were under so much pressure that they acted more like thick molasses than solid rock, becoming elastic and undergoing chemical changes as they did. Nonetheless, Dr. Pollock's theory still seemed like a stretch.

"Xavia," Tolland said. "I've never heard of water pressure alone chemically altering a rock. You're the geologist, what's your take?"

"Well," she said, flipping through her notes, "it sounds like water pressure isn't the only factor." Xavia found a passage and read Pollock's notes verbatim. "'Oceanic crust in the Mariana Trench, already under enormous hydrostatic pressurization, can find itself further compressed by tectonic forces from the region's subduction zones.'"

Of course, Tolland thought. The Mariana Trench, in addition to being crushed under seven miles of water, was a subduction zone-the compression line where the Pacific and Indian plates moved toward one another and collided. Combined pressures in the trench could be enormous, and because the area was so remote and dangerous to study, if there were chondrules down there, chances of anyone knowing about it were very slim.

Xavia kept reading. "'Combined hydrostatic and tectonic pressures could potentially force crust into an elastic or semiliquid state, allowing lighter elements to fuse into chondrulelike structures thought to occur only in space.'"

Corky rolled his eyes. "Impossible."

Tolland glanced at Corky. "Is there any alternative explanation for the chondrules in the rock Dr. Pollock found?"

"Easy," Corky said. "Pollock found an actual meteorite. Meteorites fall into the ocean all the time. Pollock would not have suspected it was a meteorite because the fusion crust would have eroded away from years under the water, making it look like a normal rock." Corky turned to Xavia. "I don't suppose Pollock had the brains to measure the nickel content, did he?"

"Actually, yes," Xavia fired back, flipping through the notes again. "Pollock writes: 'I was surprised to find the nickel content of the specimen falling within a midrange value not usually associated with terrestrial rocks.'"

Tolland and Rachel exchanged startled looks.

Xavia continued reading. "'Although the quantity of nickel does not fall within the normally acceptable midrange window for meteoritic origin, it is surprisingly close.'"

Rachel looked troubled. "How close? Is there any way this ocean rock could be mistaken for a meteorite?"

Xavia shook her head. "I'm not a chemical petrologist, but as I understand it, there are numerous chemical differences between the rock Pollock found and actual meteorites."

"What are those differences?" Tolland pressed.

Xavia turned her attention to a graph in her notes. "According to this, one difference is in the chemical structure of the chondrules themselves. It looks like the titanium/zirconium ratios differ. The titanium/ zirconium ratio in the chondrules of the ocean sample showed ultradepleted zirconium." She looked up. "Only two parts per million."

"Two ppm?" Corky blurted. "Meteorites have thousands of times that!"

"Exactly," Xavia replied. "Which is why Pollock thinks his sample's chondrules are not from space."

Tolland leaned over and whispered to Corky, "Did NASA happen to measure the titanium/zirconium ratio in the Milne rock?"

"Of course not," Corky sputtered. "Nobody would ever measure that. It's like looking at a car and measuring the tires' rubber content to confirm you're looking at a car!"

Tolland heaved a sigh and looked back at Xavia. "If we give you a rock sample with chondrules in it, can you run a test to determine whether these inclusions are meteoric chondrules or... one of Pollock's deep ocean compression things?"

Xavia shrugged. "I suppose. The electron microprobe's accuracy should be close enough. What's this all about, anyway?"

Tolland turned to Corky. "Give it to her."

Corky reluctantly pulled the meteorite sample from his pocket and held it out for Xavia.

Xavia's brow furrowed as she took the stone disk. She eyed the fusion crust and then the fossil embedded in the rock. "My God!" she said, her head rocketing upward. "This isn't part of...?"

"Yeah," Tolland said. "Unfortunately it is."

106

Alone in her office, Gabrielle Ashe stood at the window, wondering what to do next. Less than an hour ago, she had left NASA feeling full of excitement to share Chris Harper's PODS fraud with the senator.

Now, she wasn't so sure.

According to Yolanda, two independent ABC reporters suspected Sexton of taking SFF bribes. Furthermore, Gabrielle had just learned that Sexton actually knew she had snuck into his