{"id":287,"date":"2018-07-26T08:04:17","date_gmt":"2018-07-26T15:04:17","guid":{"rendered":"http:\/\/www.minormanor.org\/?p=287"},"modified":"2018-09-05T07:33:04","modified_gmt":"2018-09-05T13:33:04","slug":"geology-of-the-spanish-peaks-lovers-leap-and-the-cabin-dike","status":"publish","type":"post","link":"https:\/\/www.minormanor.org\/?p=287","title":{"rendered":"Geology of the Spanish Peaks: Lovers Leap and a Wahatoya canyon dike"},"content":{"rendered":"

This is an introduction into the geology near the Minor Manor cabin located along Wahatoya Creek just north of the East and West Spanish Peak.\u00a0 The focus is on\u00a0 Lover\u2019s Leap and the large dike (vertical wall like rock layer) located a short distance up the canyon from the cabin. The motivation was to introduce a small boulder collected at the large dike so that is could be displayed at the Pueblo Community College near Canon City.\u00a0 Secondly it might be nice for people who visit Wahatoya Canyon.\u00a0<\/em><\/p>\n

\"\"<\/a>
Aaron Minor and Jon Grenard looking north from the East Spanish Peak.\u00a0 Notice the great dikes down below.<\/figcaption><\/figure>\n

Setting<\/strong><\/p>\n

The Spanish Peaks prominently tower above the surrounding landscape along the front range of southern Colorado.\u00a0 \u00a0The West Peak above towers about 7,500 feet and the East Peak about 6,500 feet above the plains.<\/p>\n

JoAnn Grenard (Minor) has been traveling here since she was a baby.\u00a0 Her parents Henry and Jo had purchased a cabin in 1961 along what is called Wahatoya Creek (Little Kansas), draining the saddle area on the north side between the Peaks.\u00a0 Below are the two peaks as viewed from the La Veta lakes just above the community of La Veta.<\/p>\n

\"\"<\/a><\/p>\n

JoAnn\u2019s parents passed away some time ago but the four offspring (Dave, Janet, Gary, JoAnn) along with nine grandchildren and four great grandchildren have held onto the the Minor Manor cabin for now and probably well into the future.\u00a0 JoAnn and I now travel up there usually two or three times a year. The drive to the cabin officially begins in La Veta where everyone stops to buy an ice cream cone at Charlies grocery store.\u00a0We usually stop at the town cemetery to visit the grave-sites of Grandpa Henry, Grandma Jo, and Uncle Pat and then drive south past the city lakes where the picture above was taken.\u00a0 \u00a0We make a left and cross a beautiful meadow, then a right continuing pretty much due south along a beautiful mountain valley flanked on the west by the Wall Dike below.<\/p>\n

\"\"<\/a><\/p>\n

It\u2019s not only the peaks, but the great walls or dikes like this one that radiate away from the West Spanish Peak that make the area special.\u00a0Continuing south and gaining elevation, the road takes a left near the head of the valley up a hill where you crest at a gathering place commonly called \u201clovers leap\u201d gaining a view into the headwaters of Wahatoya Creek shown below.\u00a0 There are maybe 50 cabins casually strung out along the creek, sometimes called \u201clittle Kansas\u201d named for the large number of\u00a0 cabin owners from Kansas.<\/p>\n

\"\"<\/a><\/p>\n

Other than the cabins along the creek and the bull\u2019s eye mine four-wheel drive road on the northwest trending ridge above, everything in this area is part of the Spanish Peaks Wilderness managed by the US Forest Service. The string of cabins and the four-wheel drive road were grandfathered into the wilderness legislation.<\/p>\n

++++++<\/p>\n

Magma <\/strong>(A hot tempered dog\u2019s name?)<\/p>\n

The Spanish Peaks region has an interesting look to it with a number of individual peaks off to the east of the Sangre de Cristo Mountain Range and south of the Wet Mountains.\u00a0 The East and West Spanish Peaks are the most well-known landmarks.\u00a0 Like Pikes and Longs Peaks you can see them from a long way away.<\/p>\n

The best stepping off point to understand the peaks and the dikes (that I know about) is from the book \u201cGeology Underfoot along Colorado\u2019s Front Range<\/em>\u201d by Lon Abbott and Terri Cook available both in print and kindle versions.\u00a0 This excellent reference features a section on the Spanish Peaks. I\u2019m including a few of their excellent drawings in this write up to help visualize the story behind the peaks.\u00a0[1]<\/a><\/p>\n

[1]<\/a> Abbott and Cook, Geology Underfoot along Colorado\u2019s Front Range<\/em>.<\/p>\n

\"\"<\/a><\/p>\n

In the last 65 million years, the Rocky Mountains in the Colorado region has experienced three major volcanic periods. They are shown in tan, brown, and orange above and explained briefly below. The green area is representative of a rift zone (spreading plates) that is directly related to associated volcanic activity shown in orange.<\/p>\n

Magma was intruded into tan colored areas shown from around Boulder trending southwest toward the San Juan Mountains between 65 to 45 million years ago. Colorado derived a significant part of its mineral wealth as a result of these intrusions.<\/p>\n

Massive outpourings of silica-rich lava raged in a broad area shown in brown from 37 to 24 million years ago. The San Juan Mountains in southwest Colorado nicely reflect this amazing moment in Earth\u2019s history, geologically referred to as the \u201cignimbrite flare up\u201d. An ignimbrite represents hot suspension of pumice, ash, and gases flowing rapidly from a volcano, somewhat like Mt. Saint Helens, but in this time period the volcanic activity was particularly intense at times.<\/p>\n

The third volcanic period is the one critical to our story. It began about 25 million years ago and is shown in orange.\u00a0 The crust of the Earth stretched apart along a north south rift zone in Colorado shown in green providing opportunities for magma deep in the earth to intrude into overlying layers.. \u00a0The San Luis Valley reflects this rifting.\u00a0 The East Africa rift zone<\/a> is a modern day example of this type of geology.<\/p>\n

The Spanish Peaks magma stocks intruded\u00a0\u00a0into overlying sedimentary rocks (think long stringers in a lava lamp).\u00a0 \u00a0The top of these pods or stocks never surfaced remaining several thousand feet below the surface at the time.\u00a0 These intrusions were so hot that they baked the sedimentary rocks around them for a few hundred feet. Today, the tops of these magma pods are exposed today at the summit of each peak but they are not alone; the hard-resistant baked sedimentary rock is there too.\u00a0 On our trip to the cabin you can see some of core stock material of the East Peak intrusion near the cabin Lover\u2019s Leap which we touch on shortly.<\/p>\n

It wasn\u2019t just the stocks (magma pods) that intruded; they were followed by the intrusions of\u00a0 hundreds of dikes (vertical sheets of magma) into cracks of the surrounding sedimentary rock. These are evident today as one of the world\u2019s great displays of rock walls that point toward the center of the West Peak, something you can observe as you drive along the road between La Veta and Cuchara.\u00a0 Interestingly these radial dikes don\u2019t actually connect directly with the center core (stock) of the mountain. That is because they arrived later in time.<\/p>\n

There are actually three general types of dikes surrounding the Spanish Peaks. The most common are the 500 or so dikes that radiate away from the West Spanish Peak. They range in width from less than a foot to over 100 feet and some dikes run for miles across the landscape.\u00a0 All of the radial dikes have a uniform composition but two adjacent dikes often have very different compositions indicating they were injected at different times. There is a much smaller second group of dikes trending east west and a third somewhat independent group.<\/p>\n

Dikes are not uncommon but radial dikes around a core feature in such a major way as here at the West Spanish Peak is world class.\u00a0 There was just enough stress to create radial cracks in the overlying sedimentary rocks that were intruded by upward movement of magma.\u00a0 A good visualization trick is cup one hand and push up one finger into your palm so your fingers spread.\u00a0 The spreading at the time were radial cracks that enabled hot magma fluids to later be pushed up into those deeply buried sedimentary layers. <\/em><\/p>\n

All of this activity didn\u2019t happen at once, there was a sequence of events that created the Spanish Peaks and the dikes.<\/p>\n

    \n
  1. East west trending dikes located south of present day Spanish Peaks were intruded 26.6 million years ago, before the Spanish Peak stocks.<\/li>\n
  2. The West Spanish Peak stock intruded 24.6 million years ago simultaneously creating a radial fracture pattern in the overlying sedimentary rocks.<\/li>\n
  3. This was followed by the East Spanish Peak stock 23.9 million years ago.<\/li>\n
  4. The swarm of radial dikes was injected not all at once but in a series of episodes between 23.3 and 21.9 million years ago. The material in each dike is generally the same but adjacent dikes may have a completely different makeup.<\/li>\n
  5. Last of all there were a few other dikes north of the Spanish Peaks that were emplaced 21.3 million years ago.<\/li>\n<\/ol>\n

    Some specific igneous intrusion locations in the region have been age dated firming up some specific dates of these intrusions.<\/p>\n

    ++++++<\/p>\n

    Intrusions, not volcanoes<\/strong><\/p>\n

    The Spanish Peaks originated from hot molten magma that intruded deep in the earth.\u00a0 Magma reaches the surface for volcano’s but here the magma never reached the surface. The logical question in any inquisitive brain is “how is it that these peaks tower above the surrounding landscape today if they were never even surfaced?<\/em>\u00a0 We have to travel back in time 24 million years ago when the magma intruded the earth to get the answer.<\/p>\n

    Fortunately our DeLorean time machine carried us back 24 million years so we could see these large magma intrusions, but we never do.\u00a0 Instead we find ourselves on a relatively flat plain with mountains to the west but from our perspective, the Spanish Peaks don’t exist.\u00a0 If we could peer way down into the earth we would see them but the future peaks were deeply buried for the moment.\u00a0 Not only were they deeply buried, those mountains to the west would continue eroding and our future Spanish Peaks would become even more deeply buried over the next twelve million years. Those magma pods had thousands of feet of sediment on top of them and if something had not happened geologically we would never have known they existed at all.<\/p>\n

    I\u2019m again borrowing drawings from the outstanding book on Front Range Geology by Abbot and Cook to explain how you have mountains today that were deeply buried in the earth some 24 million years ago stand out as towering peaks today.[1]<\/a><\/p>\n

    [1]<\/a> Abbott and Cook, Geology Underfoot along Colorado\u2019s Front Range<\/em>.<\/p>\n

    \"\"<\/a><\/p>\n

     <\/p>\n

    We need to go back further in time to about 65 million years ago when the Rocky Mountains began forming in the first place.\u00a0 Prior to that much of the interior of what we call North America was underwater for a very long time but beginning around 65 million years ago uplift began and the Rocky Mountains began to rise. Its much more complicated but mountain building occurred over time.\u00a0 Forty million years later sediment from our Rocky Mountains was deposited all along the front range and it was these and older sedimentary rocks that magma intruded into some 25 million years ago.\u00a0 \u00a0Erosion of the mountains continued and by about 10 million years ago they were largely buried and the sedimentary rocks overlying those magma intrusions were even more deeply buried.\u00a0 The drawing above depicts this moment in time.<\/p>\n

    Beginning about ten million years ago the region began to rise again and those softer sedimentary rock layers began to simultaneously erode (if you want erosion, just raise the mountains!).<\/p>\n

     <\/p>\n

    \"\"<\/a><\/p>\n

    About five million years ago, the tops of the West and East Peak began to peak out above the surface for the first time.<\/p>\n

    It\u2019s hard to visualize how effective erosion is over a long period of time but geologically a lot can happen in a million years.\u00a0 Think about how many volcanoes\u00a0and earthquakes you\u2019ve heard about in your lifetime and recognize they represent only a small part of the many geologic changes going on all the time. Another example is that about 200,000 tons of suspended sediment flows out of the Mississippi River into the Gulf of Mexico every day.\u00a0<\/em><\/p>\n

    \"\"<\/a><\/p>\n

    The baked sedimentary rock is depicted as a contact aureole (halo like) on the drawing above.<\/p>\n

     <\/p>\n

    Over the next five million years the Colorado mountains continued to rise. Simultaneously erosion of overlying sedimentary rocks continued including the relatively soft Cuchara Formation, one of those thick layers of sedimentary rock.\u00a0 The hard-igneous rock that was once molten magma along with the adjacent baked sedimentary were resistant to erosion so they emerged as the spectacular mountains we see today.<\/p>\n

    \"\"<\/a><\/p>\n

    Notice the layered rock on the West Peak.\u00a0 This is the baked Cuchara Formation that became more resistant to erosion. The core of the mountain is igneous rock.\u00a0 Chris Grenard and Emily Kolm in the picture.<\/p>\n

    ++++++<\/p>\n

    Lover’s Leap<\/strong><\/p>\n

    Lover\u2019s Leap is actually an extension of the East Peak Stock. If you make it to the top of that peak someday, the rock will not look a whole lot different than what you can see at Lover\u2019s leap. The picture below is standing on Lover’s Leap and looking south.<\/p>\n

    The name Lover’s Leap may have a myriad of stories about how the name developed.\u00a0 I found one site describing some of the legends around the Spanish Peaks<\/a>.\u00a0<\/em><\/p>\n

     <\/p>\n

    \"\"<\/a><\/p>\n

    Looking back toward La Veta you can see more of the same rock that makes up Lover\u2019s Leap.\u00a0 One of the great dikes is visible in the background.\u00a0 Notice that the intruded igneous material is lighter in color while the underlying Cuchara Sandstone’s are darker.<\/p>\n

    \"\"<\/a><\/p>\n

    The view above is from Lover’s Leap but looking east at the rock outcrops across Wahatoya canyon.\u00a0 Like Lover’s Leap itself and the outcrop to the south, these rocks also include some of that same material related to the East Peak intrusion.<\/p>\n

    It may be helpful at this point to look at a broader perspective of the area using google earth.\u00a0 Take a good look at this next picture. It will be followed with the same view but with geology draped on top using the National Geologic Map Database.<\/a><\/p>\n

    \"\"<\/a><\/p>\n

    \"\"<\/a><\/p>\n

    The important thing to note here is the green colored rock.\u00a0 \u00a0It represents magma that was intruded to become the East Peak but it wasn’t just a single pod, notice the extension that culminates about where Lover\u2019s Leap is (which we just viewed).<\/p>\n

    ++++++<\/p>\n

    The Cabin Dike (the name of a movie?)<\/strong><\/p>\n

    \"\"<\/a><\/p>\n

    The taller cliff is a relatively prominent point\u00a0\u00a0near the Wahatoya Creek just below the Minor Manor cabin.\u00a0 The prominent upper cliff can be seen from a different perspective in the next picture.<\/p>\n

    \"\"<\/a><\/p>\n

    This second view is looking mostly west toward the cabin from an old abandoned logging trail on the hillside to the east across the stream.<\/p>\n

    \"\"<\/a><\/p>\n

    This dike is also visible from Lover’s Leap.\u00a0 It is this dike that was used to provide a donor rock to the PCC Geologic time trail in Canon City.\u00a0 The arrow called “Sample Dike”\u00a0 is pointing to that same prominent cliff.\u00a0 The term “sample dike” indicates that it is the one used for the donation material to the geologic time trail. There is one additional place you can see this dike and that is walking on top of it which is possible if you drive or walk up the Bulls Eye Mine Road (take off point a few hundred feet west of Lover’s Leap).<\/p>\n

    \"\"<\/a><\/p>\n

    This picture above is the same dike but viewed a way up the Bulls Eye Road and walking over to the edge where you can look down into Wahatoya Canyon.\u00a0 There is one place you can see both the cabin dike (red print) and another dike (white print).\u00a0 You can also see some cabins, one fairly prominently.\u00a0 Later when we were back down in Wahatoya Canyon we located the same cabin and then looked up to verify where we were previously.<\/p>\n

    One thing we notice when looking at this dike in different locations is that overall it had a similar, but not exactly the same, appearance wherever you see it.\u00a0\u00a0 It was usually fine grained and a fairly light tan color.<\/p>\n

    ++++++<\/p>\n

    A G<\/strong>eological Time Trail\u00a0<\/strong>donation\u00a0\u00a0<\/strong><\/p>\n

     <\/p>\n

    \"\"<\/a><\/p>\n

    On May 27, 2018 Jon Paul Grenard and his able-bodied assistant Emily Chadwick, backed a small pickup next to the lodged rock and pushed it into the back.\u00a0 I visually inspected the dike and this particular rock and confirmed it was the same material.\u00a0 The approximate location the rock was found in was 37\u00b025’9.52\u201d N and 104\u00b058’27.59″W.\u00a0 \u00a0The particular small boulder was selected because it had broken off the main dike, rolled down hill and lodged up against a power pole.<\/p>\n

    Based on the Johnson Report, the West Spanish Peak is made up mainly of one of the varieties of a relatively fine grained igneous rocks.\u00a0 For our simplified purposes here, they typically a medium to coarse grained igneous rocks.\u00a0 The Lindsey Report describes the rock compositions for the West Spanish Peak radial dikes as monzonite and syenite porphyries. In general, they described the textures as relatively fine grained (crystalline to glassy) with a lot of ground mass. \u00a0\u00a0They also describe the textures of the rocks of the Spanish Peaks region are holocrystalline phaneritic (crystalline) and porphyritic-aphanitic (some crystalline texture to little crystalline or glassy texture) with as much as 70 percent of the rock composed of groundmass or an aphanitic texture[1]<\/a>.\u00a0\u00a0 Maybe just think of the dike rock as a very fine grained, light colored, igneous rock with a few small crystals in it (porphyritic).\u00a0 It\u2019s a bit gray on this specimen due to weathering.<\/p>\n

    A reasonable estimate of the age of the dike rock based on an age dating diagram from the Penn and Lindsey report used for the time trail is 22 \u00bd \u00a0million years old [2]<\/a>.<\/p>\n

    A special note on the Geologic Time Trail is that we had some extensive damage on July 21, 2018 due to flooding that was result of several inches of rain falling in a very short period of time. A restoration plan is getting underway ASAP.\u00a0 \u00a0Canon City had a lot of damage to homes also as a result.<\/p>\n

    [1]<\/a> Penn and Lindsey, Tertiary Igneous Rocks and Laramide Structure and Stratigraphy of the Spanish Peaks Region, South-Central Colorado<\/em>.<\/p>\n

    [2]<\/a> Penn and Lindsey.<\/p>\n

    ++++++<\/p>\n

    The Cuchara Formation (Sandstone)<\/strong><\/p>\n

    \"\"<\/a><\/p>\n

     <\/p>\n

    We would be remiss not to mention the rock that was intruded by the\u00a0 Spanish Peaks some 25 million years ago. Some of this sedimentary rock included intruded the Cuchara Formation which is fairly prominent in the La Veta area as relatively flat lying cliffs. The formation is several thousand feet thick representing sediment that was washed down off from the Culebra Range (part of the Sangre de Christo mountains) well before the magma intruded the area.\u00a0\u00a0This sediment accumulated as alluvial fans and river deposits adjacent to the mountain range. These are mostly fine grained but some layers have pebbles and larger material.\u00a0 The parts of this formation close to where the magma was intruded are hard while most of it remained relatively soft.\u00a0 This view of the Cuchara Formation is just down the road from Lover’s Leap and a careful observation will reveal soft red mudstone\u00a0 visible below the sandstone.<\/p>\n

    +++++++<\/p>\n

    Map of igneous intrusions in the area.<\/strong><\/p>\n

    \"\"<\/a><\/p>\n

     <\/p>\n

    References: <\/strong><\/p>\n

    Abbott, Lon, and Terri Cook. Geology Underfoot along Colorado\u2019s Front Range<\/em>, 2012.<\/p>\n

    Johnson, Ross B. Geology of the Igneous Rocks of the Spanish Peaks Region, Colorado<\/em>. Washington: U.S. Govt. Print. Off., 1968.<\/p>\n

    Penn, Brian S, and David A Lindsey. Tertiary Igneous Rocks and Laramide Structure and Stratigraphy of the Spanish Peaks Region, South-Central Colorado: Road Log and Descriptions from Walsenberg to La Veta (First Day) and La Veta to Aguilar (Second Day)<\/em>. Denver, Colo.: Colorado Geological Survey, Dept. of Natural Resources, 1996.<\/p>\n","protected":false},"excerpt":{"rendered":"

    This is an introduction into the geology near the Minor Manor cabin located along Wahatoya Creek just north of the East and West Spanish Peak.\u00a0 The focus is on\u00a0 Lover\u2019s Leap and the large dike (vertical wall like rock layer)<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-287","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/posts\/287","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=287"}],"version-history":[{"count":39,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/posts\/287\/revisions"}],"predecessor-version":[{"id":361,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=\/wp\/v2\/posts\/287\/revisions\/361"}],"wp:attachment":[{"href":"https:\/\/www.minormanor.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.minormanor.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}