Copper Replacement Agate

Cumulate rock

Cumulate rocks are plutonic rocks in which cumulus minerals have been concentrated during the cooling of the magma chamber.

This sample of cumulate rock is composed by interstitial plagioclase (white), called intercumulus, and pyroxene (dark-coloured in the hand sample and brownish in thin section), called cumulus. In thin section, we can also see biotite and opaque minerals.

Crystals study

i'm so tired

Geologically speaking,

Fossil Friday: Cynognathus

Cynognathus crateronotus has been a pretty big deal in paleontology since the late 1880's but was brought to the public's attention by this gem:

(If you are somehow not aware, this is BBC's 1999 Walking with Dinosaurs. If you haven't seen it, go watch it now. It's fantastic).

While the show depicted Cynognathus living alongside Postosuchus and Coelophysis, it actually hasn't been found in North America where the pseudosuchian and dinosaur have been found. Those two are also Late Triassic animals while Cynognathus is a middle Triassic animal.

Cynognathus was first discovered by Harry Seeley in southern Africa in 1889. He also named the genus and type species. The name Cynognathus means "dog jaw" in reference to the very mammalian -looking jaw.

Cynognathus was part of the cynodont family of early therapsids, the clade which mammals belong to. It had many characteristics in common with mammals including differentiated teeth,

a secondary palate which indicates it could breathe and swallow simultaneously, a lack of belly ribs which might indicate the presence of a diaphragm and concentrations of pits and canals on the snout which could support whiskers.

However, it still retained some primitive features like multiple lower jaw bones, and semi-sprawled legs (however, recent studies of living mammals indicate that only certain groups of mammals have the upright posture we've come to associate with mammals).

Cynognathus was one of the fossils used as a piece of evidence for continental drift by Alfred Wegener as it has been found in southern Africa, Argentina, and Antarctica.

Tune in Sunday at 6pm for live stream discussion with colleagues as we talk about a large sauropodomorph from China. We will also answer a handful of questions at the end, some come prepared and we may choose you! Fossilize you later!

I made these as a way to compile all the geographical vocabulary that I thought was useful and interesting for writers. Some descriptors share categories, and some are simplified, but for the most part everything is in its proper place. Not all the words are as useable as others, and some might take tricky wording to pull off, but I hope these prove useful to all you writers out there!

(save the images to zoom in on the pics)

Oh, that’s very helpful indeed!

!!!

Happy 4 yr anniversary of me discovering my hatred for measuring sections of carbonates! But boundstones get a pass as who doesn't like stromatolites?

150 cm long Jacob staff w/ 20 cm increments and 10 cm at the top. Cretaceous age Glen Rose Limestone.

This rock formation is at Bodnant Garden in North Wales. I’m still learning, so I don’t know why it’s like that. Feel free to leave a comment if you know.

Recently got back from Death Valley, my fifth visit in the last 12 months (I think I like going there…). Not much new stuff on this visit, but I did get to see my first chuckwalla (a large lizard)! Not much as far as wildflowers go this year, they didn’t have as wet of an autumn/winter as in other recent years.

My friend the chuckwalla (Sauromalus ater):

He’s about 30 cm/1 ft long!

My friends the zebra-tailed lizards (Callisaurus draconoides):

On the left is a juvenile. Adult, on right, is about 9 cm/4 inches long excluding tail.

Here’s some geology:

Natural Bridge, the 2nd tallest but widest-spanning natural bridge in the park:

(See wife at center for scale!)

Brine pool out on the salt flats:

About 1.5 meters/5 feet wide

The ever-classic Mosaic Canyon:

Here, Precambrian Noonday Dolomite (white/yellow) metamorphosed into marble and stretched by intense pressure during mountain uplift. Later, that rock was carved into a slot canyon and filled with debris. That happened long enough ago that those debris flow deposits solidified into rock (gray, mosaic-like rock). Then, it was uplifted again and the canyon was re-carved through both the marble and the breccia!

Rhodochrosite & Quartz | Hotazel, Kalahari, Northern Cape Province, South Africa

If not food, why looks tasty?

Slate, quartz and pyrite, folded by tectonics

WHY. IS IT. ALWAYS. YOU!!!!!!!!!!

Looking at some sedimentary rocks today! Today's suspect is some silty limestone!

Geology Casual Reads

Last week we had the luxury of having Marcia Bjornerud do a talk via Zoom at our university, it was really thought provoking for a couple reasons.

If you don't know Marcia, she is the author of a couple books including 'Timefulness: How thinking like a geologist can help save the world' and 'Turning to Stone: Discovering the subtle wisdom of rocks'. These books are typical nonfiction works that are written in casual english allowing people didn't get a degree in geo to enjoy it.

Have I read them? No... Because I didn't really no they existed until last week which is actually really sad. That isn't exactly my point though.

My point! Is!

Her entire talk was centered around the history of geology, talking about key figures and setbacks they had to face because of religion/ politics/ people in general looking down on geology as a science (think Big Bang Theory).

The talk's main focus was just exploring how geology has faced many setbacks in the past, and how we are still actively seeing the same setbacks, looking at the oil and gas industry, and people branding geology as this negative force against climate change (which like 99% of geologists also hate oil and gas industry as well), and so it gets shunned as a choice for incoming students with an interest in geoscience, even though a lot of environmental remediation jobs want people with a geology background.

Her final statement was essentially the same sentiment a lot of geo-communicators have which is "We have to get geology out there", for her it is writing this nonfiction literature, for other geoscience communicators it's by making Tiktoks/Reels to generate more incoming students, but there is a general sense of hopelessness which is just... geoscience isn't taught in most schools save, maybe... 1 month of content.

There is a reason a lot of conspiracy theories revolve around misunderstandings of the earth... ANYWAY, I could rant about that for ages but I hate that line of thought.

What impact this talk had on me was simple... It was a sense of pride for my science. I can't begin to tell you how exhausting it is to justify studying rocks, because let me tell you, you ALWAYS have to justify yourself. For the most part, you kind of just smile and get used to it. Yet listening to this talk granted me so much relief I couldn't even explain it.

ALL THIS TO SAY:

I want to read these books, and I want more casual geology non fiction recommendations, please tell me what you have read!

I have read the 'sixth extinction by Elizabeth Kolbert already, so I will recommend that (it is a bit depressing though)

Other media recommendations I have right now: 'Orb: on the movements of the earth'

Native Copper psuedomorph of Aragonite

Locality: Corocoro, Pacajes Province, Pa Paz Department, Bolivia

Native copper with partially oxidized, green surface which has replaced prior aragonite, perfectly preserving the hexagonal crystal shape.

despite what popular opinion may lead you to believe, some rocks actually do have scientifically-proven auras! Unfortunately, those rocks are uranium and the aura is cancer. 

Though rock auras are rare, rock magic is common. The most common form of rock magic is Concussion.