Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: TUESDAY, April 12, 1994                   TAG: 9404120049
SECTION: VIRGINIA                    PAGE: B-1   EDITION: METRO 
SOURCE: RAY REED
DATELINE:                                 LENGTH: Medium

THINK OF IT AS A GIANT COLLISION . . .

A: Erosion has been the primary force changing our mountains for 260 million years.

How tall did our mountains stand before that? Maybe as high as Mount Everest.

How did they get so big? From a continental collision, sort of like two cars hitting head-on with the hood flying up on one of them.

The vehicles in that wreck were tectonic plates, which are like barges floating on the Earth's pliable interior. When the hot core of the Earth bubbles and moves, it pushes these plates around. It's slow as taffy but the power is unmatched.

This information is courtesy of Richard Bambach, a paleontology professor at Virginia Tech who summarized millions of years into one telephone call.

That collision 260 million years ago was the most recent of several. A plate carrying Africa and part of South America piled into North America and thrust its leading lip on top. Peaks the size of today's Himalayas were pushed up.

We've seen the evidence along roads cut through mountains. Ever notice that sometimes the layers of rock lean at a 45-degree angle? They got pushed up into folds when land masses collided.

Our mountain ridges are the upturned edges of those rocks. The soil that made them Himalayan proportions washed into the valleys and out to sea.

If we drive into West Virginia, mountains take on different characteristics. Those were originally high table lands. The collisions shoved them around but they didn't get the overthrust that wrinkled rock layers vertically into mountains like ours. West Virginia's rock strata still lie mostly level.

Some of our Roanoke-area mountains formed in different eras and from different collisions. Hanging Rock and Catawba Mountain were raised at about the same time; Fort Lewis Mountain, which lies between them, was formed a few million years later.

About Easter time

Q: How is it decided which Sunday is Easter? Is it related to when Daylight Saving Time starts? S.R., Roanoke

A: Easter and Daylight Saving Time are not related, except that both usually occur in April.

Daylight Saving Time always starts the first Sunday in April. We can count on that until Congress tinkers with it again.

The first Sunday in April had its DST kickoff in 1987, and provided a kick-start for sales of sports gear and yard-work equipment.

Before that, DST started the last Sunday in April every year since 1967, except during the energy criss of 1974-75 when we had DST all year.

Easter follows the first full moon after March 21, the vernal equinox.

This makes March 23 the earliest date for Easter, and it can come as late as April 25. This is from the World Almanac's list of Easters for the 20th and 21st centuries.

Easter has its roots in the Jewish holy day of Passover. The two events usually are observed within a week of one another.

Got a question about something that might affect other people too? Something you've come across and wondered about? Give us a call at 981-3118. Maybe we can find the answer.