NORTH COUNTY: Geologists hope to date Mount Calavera, Morro Hill's volcanoes
By BARBARA HENRY - Staff Writer | ∞
Mountain bikers ride a trail near Mount Calavera on Wednesday evening. (Photo by Don Boomer - Staff Photographer) Mount Calavera region events
Conservation group Preserve Calavera and the Agua Hedionda Lagoon Discovery Center regularly host events related to the region's plants, animals and rocks. Here are a few:
-- Lecture on pollination, 7 p.m., Wednesday at the Agua Hedionda Lagoon's Discovery Center. For information, call (760) 804-1969 or visit the discovery center's Web site at www.aguahedionda.org.
-- Pollinator Awareness Festival, 10 a.m. to 4 p.m., Saturday at the discovery center. Final day of the center's weeklong emphasis on the bees, butterflies and birds that pollinate flowers. A hummingbird presentation is planned for 11 a.m., and a beekeeper with a live hive will talk at 1:30 p.m.
-- A talk on coyotes and the natural environment hosted by Preserve Calavera is planned for August. For information on that event and other activities hosted by the group, which focuses its efforts on the Mount Calavera region, visit http://www.preservecalavera.org
Hikers check out the view from the top of Mount Calavera on Wednesday. (Photo by Don Boomer - Staff Photographer) 
MiraCosta College geology professor John H. Turbeville uses the ground to make a sketch Saturday as he leads a Preserve Calavera-sponsored walk on Mount Calavera. Turbeville has hosted talks on the peak's volcanic roots for several years. (Photo by Don Boomer - Staff Photographer) NORTH COUNTY ---- Area geologists are poking into part of Carlsbad's Mount Calavera and Oceanside's Morro Hill hoping to find out how long ago these two ancient volcanoes tossed ash and rocks into the air.
"There's really quite a difference between 20 million and 30 million years in what was going on (geologically) in this part of the world," said Tom Demere, curator of paleontology at the San Diego Natural History Museum. "That's what makes these little volcanoes so interesting."
He and colleague David Kimbrough of San Diego State University have taken samples of Mount Calavera ---- a distinctive skull-shaped mountain in Carlsbad's far northeastern edge ---- with a goal of age-testing them later this year.
Their initial estimate is that Calavera's volcanic "plug" or core throat area, is 28 million years old, Demere said Thursday.
If so, that might make it the oldest of its type in the San Diego region, he added.
He isn't the only person eyeing Mount Calavera with interest.
MiraCosta College geology professor John H. Turbeville has hosted talks and walks about the peak's volcanic roots for several years.
He also has plans to do his own age-dating of the volcanic material.
On Wednesday night, he told a standing-room-only crowd at the Agua Hedionda Lagoon Discovery Center that he finds Calavera fascinating even though its long-ago eruption was tiny compared with the 1883 eruption of Krakatau in Indonesia.
Krakatau was so impressive that "when it erupted, they heard it in Europe 10,000 miles away," he said as several audience members gasped.
Its eruption rated a six out of eight on the Volcanic Explosivity Index scale, or the volcanic equivalent of the earthquake assessment system known as the Richter scale.
For comparison, tiny Mount Calavera is estimated to have been only a .5 on the volcanic scale, Turbeville said.
Still, it tossed out rock chunks and plenty of ash. Demere said he believes that ash deposits he has seen in Chula Vista and National City may have come from Calavera's eruption.
"The chemistry is right," he said as he discussed the makeup of the ash materials.
Northeastern Oceanside's Morro Hills, which has lava flows as well as a volcanic plug, and Mount Calavera aren't the only evidence of ancient volcanic activity in the San Diego region.
There is widespread evidence of volcanic activity from 140 million years ago, when dinosaurs walked the Earth.
However, those are scattered rock pieces in places such as San Elijo Hills rather than an intact throat of a volcano, Demere said.
More recent volcanic plugs than the Morro Hill and Calavera spots also exist.
Ones in Jacumba Valley are estimated to be 16 million to 18 million years old, Demere said. There's also a little volcanic deposit just north of Scripps Pier known as Dike Rock that dates from 10 million years ago, he added.
Because they're older, Calavera and Morro Hill could provide clues about what was happening in the area geologically between 20 million and 30 million years ago, Demere and Turbeville said.
At that time, the region looked much like it does today, but there was much more movement of the Earth's crust in this area, Demere said.
Turbeville told the crowd Wednesday night that Calavera was created the same way that the now-volcanically active Cascade Range of the Pacific Northwest began: Offshore land was shoved under a continental crust, melted under tremendous heat and pressure and then found its way back to the surface through cracks in the Earth's surface.
Mount Calavera region events
Conservation group Preserve Calavera and the Agua Hedionda Lagoon Discovery Center regularly host events related to the region's plants, animals and rocks. Here are a few:
-- Lecture on pollination, 7 p.m., Wednesday at the Agua Hedionda Lagoon's Discovery Center. For information, call (760) 804-1969 or visit the discovery center's Web site at www.aguahedionda.org.
-- Pollinator Awareness Festival, 10 a.m. to 4 p.m., Saturday at the discovery center. Final day of the center's weeklong emphasis on the bees, butterflies and birds that pollinate flowers. A hummingbird presentation is planned for 11 a.m., and a beekeeper with a live hive will talk at 1:30 p.m.
-- A talk on coyotes and the natural environment hosted by Preserve Calavera is planned for August. For information on that event and other activities hosted by the group, which focuses its efforts on the Mount Calavera region, visit http://www.preservecalavera.org
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grick wrote on Jun 23, 2008 7:02 AM:that's really cool, I had no idea that those were ancient volcanoes.
Paula wrote on Jun 23, 2008 7:28 AM:Ok, it is a really cool article but the professor who said Krakatoa was heard in Europe is so wrong! The farthest it was heard was a little over 3,000 miles away, less than half the distance he claimed. It is incredible still, but he needs to get his facts straight.
C-bad believer wrote on Jun 23, 2008 7:41 AM:why don't they just ask bud lewis how old they are?
prof wrote on Jun 23, 2008 8:35 AM:Liberal academics wasting taxpayer dollars studying old useless landforms = HUGE BOONDOGGLE!
Victoria wrote on Jun 23, 2008 8:57 AM:I have lived near the Calavera area for nearly 25 years. I used to ride my horse bareback through the hills. I used to hike through the hills with my boy. We would even drop a line in the lake just for the fun of it. Things have changed monumentally. I live across Lake Blvd. and now because of the new homes and families, it has forced coyotes, snakes, opossoms, bunnys, just to name a few, into my backyard. Yes, I have known about this "volcanic" area for years. Can we do nothing to keep it preserved? Did I just read that 860 more homes are to be built? Wow. Not cool. I am sure the activists will not let this happen. I wish that my children could grow up knowing about this beautiful preserve, if we can preserve it, instead of the fact that their friends bought homes here that they couldn't afford, all at the expense of something that should be forever a historically preserved site. I can only hope.
Victoria wrote on Jun 23, 2008 9:01 AM:Wow, Prof! To me, personally, I would rather put my tax dollars into this historical site instead of put it, for example to the hospital that sees my ill child after all of the illegal immigrants who don't pay tax dollars!! You must not have children that need cultural or historical information on where they grew up or came from. hmm...
Bobby wrote on Jun 23, 2008 9:35 AM:Used to go down there all the time as a kid, I wonder why they didn't take some better pictures of the volcanic ash deposits and obsidian (volcanic glass) Oh wait my bad... Developers built over that...
Not to mention they also built over a huge archeological site in the process.. Yes native americans had an establised camp there, nobody will ever know about it due to the fact that houses now sit atop it...
Thanks Carlsbad sellouts, and big developers greed!
Im Rich woo hoo wrote on Jun 23, 2008 11:03 AM:Get out the shovels and start digging!
Could be diamonds down that volcano pipe.
CBad Thirty Plus Yrs wrote on Jun 23, 2008 11:55 AM:Consider emailing this story and your concerns for the preservation of the area to anyone you know in North County, especially in Carlsbad.
Its Already Obvious wrote on Jun 23, 2008 12:43 PM:The blistering pace of development in Carlsbad is one reason I live in Encinitas.
To Im rich woo hoo wrote on Jun 23, 2008 2:33 PM:Sorry bud, no diamonds down there, that would have been exploited years ago... Need Kimberlite for that
But if there was, everyone would complain about the mining operation and the dust so it just wouldn't work anyways...
Calaveras used to just be a gravel pit back in the 50's... Now they are fighting to preserve it... Ha Ha take that Temecula
-Bobby
Phone wrote on Jun 23, 2008 4:36 PM:Interesting!!!
SenorPatos wrote on Jun 23, 2008 4:43 PM:Hey. How's it goin, gomes? To the prof...you're a BOONDOGGLE! To Victoria, I like bunnies too. Jah. Don't forget to Barack the McCain!
Vista Granny wrote on Jun 24, 2008 7:43 AM:The Preserve Calavera group HAS saved Mount Calavera. They work very hard and DIDN'T use tax dollars to save Mount Calavera or the creek land along side 78. Sorry, having a senior moment - can't remember all place names. They raised money through donations -- and bought the land!!! So, you who hate environmentalists just be quiet!!!
So cool wrote on Jun 26, 2008 9:10 AM:Wow! That is so cool. Thanks for the information. I have never seen a volcano before. I hope to get to see it soon. I had no idea we had this in our area. Where is the best place to go to check this out?
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