Geology Rocks
WHAT: RMGA MEMBERS MEETING – Renaissance Denver Downtown
WHEN: Monday, May 11, 2020; 6:30pm - Short meeting 6:45 - 7:30pm - Program followed by questions
WHERE: Via Zoom.
PROGRAM: Join longtime RMGA member Steve Kaverman for our May program. Ethan Magusin, RMGA's 2020 Program Chairman has arranged for Steve to present what promises to be a practical and educational look at interpreting geology...for the non-geologist. The program, titled Geology Rocks was originally presented during the 2019 Tour and Talent Exchange Conference for the International Association of Tour Directors and Guides (IATDG), held in Orlando last November.
RMGA Membership Meeting Review
Membership Meeting – Geology Rocks
May 11, 2020
The program was a virtual program on Zoom. President Sherry Moon conducted a short business meeting. Director at Large Mike Pearl updated the membership on the revision of both the Bylaws and Policies documents which Tom Jensen has uploaded to the website. Mike noted the year-end term change for the Board from December 31 to May 31. The slate of officers will be presented in future years in March, elected in April, transition with the outgoing Board in May and take over as of June 1. Mike also went over the Records Retention policy and the changes made to both the Bylaws and Policies regarding retention.
All attending were asked about their current health since we have been together with them – actual meetings have recently been prohibited because of the effects of the Coronavirus (COVID19).
Sherry went over the latest blasts and updates from CTO. She also commented about certification – because of the tourism shutdown, RMGA may need to change the number of hours required for recertification for next year.
Sherry also noted that cruise ships are slated to restart August 1 and are booked solid for their comeback cruises. She also noted that she is moving to Santa Fe soon.
Treasurer Wendy Pickering noted that in order to apply for unemployment insurance, any applicant needs to certify earnings in the past year of at least $2,500.
Vice President Ethan Magusin then introduced the speaker for the evening – member Steve Kaverman in Canon City who presented a PowerPoint presentation about Colorado’s geology. This presentation was originally presented at the IATDG conference in Orlando, Florida last year. The focus is to teach guides how to interpret geology from a non-geological background.
Geology describes structure of the Earth, how forces have shaped it and also provides information on plate tectonic evolutionary process.
Rock forms the crust of the Earth, are naturally occurring solid mass or combination of minerals. There are 5,413 types of minerals.
There are three types of rocks: Igneous, Metamorphic and Sedimentary.
Igneous rock is cooled magma on the surface (granite, basalt) the lava cooled on the surface. Tuff is super-hot rocks and ash blown from volcanoes, that fuses together as it settles to the surface. Other examples would be Rhyolite (common in Yellowstone National Park) and obsidian (natural glass).
Metamorphic rocks are altered by heat and pressure. Examples are Gneiss and schist.
Sedimentary rocks are formed by accumulation of eroded material, conveyed by wind, water, or glaciers to the point of deposition, or when suspended material in lake or sea water settles. Examples are sandstone, limestone (formed in ancient oceans), shale, coal, mudstone and salt. The Grand Canyon is predominately sedimentary rock. Antelope Canyon in Arizona (Steve had a fascinating photo of the canyon) is a slot canyon eroded by floods through sedimentary rock. Tyndall stone is sedimentary rock formed from aquatic sediment.
Slowly, over time, rocks cycle or transition from one type of rock, eventually becoming another type of rock. The geology time scale dates rocks visible on the surface around Cañon City from 1.7 billion years old, to 60 million years old. Human fossils have never been found as the fossilization process typically takes longer than homo sapien has existed.
What types of rock are where?
Hawaii or Yellowstone are Igneous.
The Rocky Mountains in the U.S. are predominantly metamorphic, with sedimentary rock more common in the Canadian Rockies.
Utah is sedimentary. Sedimentary rocks are easy to see in the Western US – the color red, denoting the iron oxide contained in the rocks is very common in the West.
Deposition is the process by which sediments are added to the land mass. Layers are an indication of the period of deposition: where horizontal layers denote time, and vertical layers denote activity such as uplift, folding, faulting, fracturing from freeze and thaw cycles.
Alluvial deposits are deposition caused by moving water, such as in a flash flood, or at the mouth of a large river.
Harder materials erode more slowly -- soft materials more quickly. Thus, hoodoos in Bryce NP and arches in Arches NP, or in pinnacles in Monument Valley are the harder material, more resistant to erosion that remain after the soft has eroded. Differential erosion is how geologists refer to the ‘differential’ in erosion rates between hard and soft rocks. Hard materials erode into cliffs, soft erodes into slopes. Columnar basalt (an igneous rock) shows a classic vertical erosion pattern. The Morrison formation tends to erode more quickly, forming slopes rather than cliffs. Travertine is formed by minerals left behind as water from mineral springs (Mammoth Hot Springs in Yellowstone NP, for instance) evaporates. Geologically altered rhyolite with its distinctive yellow hue is how Yellowstone NP got its name.
Definitions: in general a canyon is wider than it is deep, and a gorge is deeper than it is wide.
A fossil is the preserved remains, impression, or trace of a once-living thing from a past age, that has been turned to stone. Fossils form only in sedimentary rock. Near Cañon City, trace fossils that are 450 million years old (Ordovician age) can be found in one layer, while sea fossils that are only 65 million years old can be found in another. There are also dinosaur tracks near Canon City that are 107 million years old.
Fossilized dinosaur “poop” is called coprolite -- a definition school kids may find funny.
Steve noted that around Florissant, Colorado are fossilized trees. Near La Veta Pass volcanic dikes are common -- radiating away from the Spanish Peaks, which are ancient volcanoes.
Sherry Moon added a way to remember how the Grand Canyon was formed:
D – deposition
U – uplift
D – downcut
E – erosion
Contact Information:
Steve Kaverman
380 Antero Drive
Cañon City, Colorado USA 81212
303-717-2765
tourismchampion.com
Written by Nancy Brueggeman