Lake Tahoe Rocks! (Exploring beautiful places with science)
Lake Tahoe rocks!
Personal photo looking east towards the Nevada side of Lake Tahoe from California.
Ah North America, the northernmost part of the Americas. In the middle of this, towards the west, out near the Pacific in Northern California (and Nevada too) is one of the most beautiful lakes on Earth - Lake Tahoe. Here the pink sunset (#nofilter) is enhanced from fires.
But what makes this so beautiful? My amazing photo skills? Or am I simply capturing a sight that nature made easy for me to make beautiful?
The mountains? The lake itself? Why are they here? These questions will be address briefly in this post.
Spoiler alert: the geology and tectonics here are, well, everything (Figure 1).
Let's look at this shall we?
Figure 1: GEOLOGIC MAP OF THE LAKE TAHOE BASIN
CALIFORNIA AND NEVADA (Saucedo et al., 2005). You can find this map here
By looking at figure one, we can see a number of things, one that there are a number of different materials seen here (rocks and different sediments) each represented with different colours. Intrusive rocks, volcanic rocks (see photo above), and the evidence of glaciers passing by (e.g. moraines, etc) all give insight to the past.
But the really important thing here, that can be seen on the map are the long black lines (Figure 2).
Figure 2: Here you can see I circled the "West Tahoe Fault". So these black lines are all fault lines?! Wow! (note: not all black lines, some of the black lines are simply contacts between different "units"), but most of the linear lines on the map are faults of some sort, some have names which helps too).
Thus faults, on either side of the lake are structural controls on the distribution of the basin, in this case now filled with water. Because these faults have a vertical component (see figure 3), and there is extension here (or stretching of the crust), many of these faults are "normal faults" (again see figure 3). When these faults move, different blocks drop down. Rainfall and snowmelt from the surrounding mountains flow down into this basin keeping this beautiful lake alive and (sometimes) filled almost to the brim of the basin.
Figure 3: Different types of faults. Can you see how these normal faults around Lake Tahoe control why Lake Tahoe is present in a fault-controlled basin?
From looking at photo one, on the other side of the lake there are mountains, these are those seen on the right side of the map (also above). In between there are faults dropping down the centre of the basin whilst the flanks of the basin are popping up (making cool mountains for us to play in).
Tectonics controls everything. Without tectonics, without geologic faults, no Lake Tahoe and thus no cool sunset photo above.
Formations of basins, global climate, cool places to take photos, or even help you find a nice place to drink tea and "get away from it all" are all better with the movement of plates through tectonics.
For more, science, art, and photography please check out my blog @snowyknight
GEOLOGIC MAP OF THE LAKE TAHOE BASIN
CALIFORNIA AND NEVADA, George J. Saucedo
Digitized by Jason D. Little, Sarah E. Watkins, Jennifer R. Davis, Marina T. Mascorro, Victoria D. Walker and Eric. 2005. California Geological Survey.
You can find this map here
Feel free to yak about any of this below.
Original insight, figures, photo from @snowyknight.
Bonus song in relation to this post.