Brian Ricketts @kiwigeolog.bsky.social

Sedimentology, geofluids, sedimentary basins, volcanoes, planets - website for eager Earth Sci students at www.geological-digressions.com 🇨🇦-🇳🇿

Reposted by Brian Ricketts
lokier.bsky.social's profile picture
Stephen Lokier @lokier.bsky.social
4d
Today, Lesli Wood will present a webinar on deepwater fans & dynamic Caribbean sedimentation.

We are also celebrating 6 years of #sedsonline with an exciting announcement!
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Reba Masterson’s (1882 – 1969) reputation as the first female petroleum geologist is founded on her fierce independence and determination to succeed in a male-dominated profession.
www.geological-digressions.com/reba-byrd-masterson-1882-1969/

Another entry in Pioneering women in Earth Sciences
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On a recent trip to Tasmania - MONA (Hobart)- the Museum of Old and New Art. The gallery is excavated in Triassic fluvial sandstone. It's one of the quirkiest galleries I've ever visited. The artistic emphasis is sex, death, & guts.

An advertisement advises folk to "... Talk crap about the art."
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For International Women's Day and Women's History Month, here's the list of Earth science pioneers I've written about so far (compiled in approximate alphabetical order).
Page link: www.geological-digressions.com/how-to-do-field-tasks/pioneering-women-in-earth-science/
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Calcite-cemented coastal dunes (aeolianites) etched by wind, rain, and sea spray. The more-or-less vertical tracery formed originally as burrows (excavated by former dune-dwelling critters) and plant roots. Geo age uncertain. Sandy Cape, Western Australia. The head shape reminds me of Eeyore! ⚒️🧪
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Some tallish sunflowers - the one at the back is nearly 4 m. Also some quince nearly ready to pick. The tomatoes are climbing through the window. They all got a good soak during the last storm - 253 mm rain in 24 hours.
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Some of the nicest, rectangular fracture networks in pebbly mudstone - diamictite (age uncertain but probably middle to late Paleozoic). Friendly Beach, eastern Tasmania. A bit like a block of chocolate where each piece is filled with crunchy pebbles. ⚒️🧪
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The list so far of Pioneering Women in Earth Science at this point focused on 18th - early 20th C. In approx order of compilation. Most accounts are brief - but I list as many accessible references as possible. Lots still to write about ⚒️🧪🌊

www.geological-digressions.com/how-to-do-field-tasks/pioneering-women-in-earth-science/
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My contribution to the discussion on SAND. I combine a photo of large dunes masquerading as small dunes, made of Martian sand in the Namibian dune field - oodles of sand but no beach. ⚒️🧪
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A casual stroll along the beach. Shark Bay, Western Australia. Also where the Monkey Mia dolphins come in for a feed - usually accompanied by a couple of local pelicans looking for leftovers ⚒️🧪🌊
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Limestone Pinnacles near Cervantes, Coral Coast, W Australia. Mostly shelly limestone, perhaps 2-3 million years old (age is uncertain). The karst landscape formed a few 10s of 1000s of years ago. Most <5m high. Temperatures in the mid 30s C in mid-November when we were there. ⚒️🧪
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Detached beach ridge at the inactive margin of a small fan delta - the active braided part is on far side. An older dissected delta segment in the background. Large ice polygons across the delta surface. Ellesmere Island. About 600-800 m wide. ⚒️🧪🌊

www.geological-digressions.com/beach-microcosms-as-fan-delta-analogues/
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Actually not quite zero vegetation - may have been some primitive lichen-like plants.
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An easy walk along sea cliffs of Cambrian-Silurian Tumblagooda Sandstone, ~ 450-400 million years old, S of Kalbarri, W Australia. Lots of crossbedding. Ancient river deposits at a time of zero terrestrial vegetation.
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Mary Somerville - the person for whom the word scientist was coined by William Whewell in his 1834. She was a polymath, an intellectual tour de force at a time when teaching women to read and write let alone think deeply was frowned upon or ignored ⚒️🧪🌊
www.geological-digressions.com/mary-somerville-1780-1872/
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Goat I. northern Tasmania. Strongly foliated metamorphic rks. A haven for Small Blue Penguins, nightly raucous partying as they make their way onshore to their nests, with the tide - we had one under our bedroom window!⚒️🧪🌊
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Lovely intertidal, northern Tasmanian serpulid worms encrusting a boulder (~60 cm wide). Each marine worm secretes its own tube out of calcium carbonate - tubes 2-3 mm diam. These critters can build extensive communities on rocky shores. ⚒️🧪🌊
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Another great hike - Cradle Mountain N Tasmania. Dove Lake ringed by Mesoproterozoic greenschist ~1000-1600 million years old. The skinny horizontal layers are Permian ~250-298 m yrs so an age gap up to 1300 m yrs. Jagged peaks are dolerite that intruded the Permian deposits about 175 m yrs ago ⚒️🧪
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Silurian felsic volcaniclastics, or if you prefer nice sea-worn bedrock, eastern Tasmania. Some of the most colourful lichen I've ever seen - this stuff is vivid. Can see it along much of NE Tasmania above high tide notably on the aptly-named Bay of Fires that we didn't get to but this will do ⚒️🧪
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An excellent 12 km hike across Devonian syeno-granite - granodiorite intrusives, with a stop at Winglass Bay, Tasmania. 1 wallaby, 1 bird-eating snake (up a tree), lots of quartz-feldspar sand, and stiff 75 year-old knees ⚒️🧪
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Hutt Lagoon W Aust on a dull day - pink hues are subdued ~14 km long & separated from the ocean by a sand barrier. Lake level is a few m bsl so sufficient hydraulic drive for sea water flow. It's hypersaline -halite precipitates along the shore. The colour caused by beta-carotene producing algae ⚒️🧪🌊
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Shark Bay (W Aust) in Nov is warm- 30ish C but the rewards... Here, extensive sea grass meadows at Monkey Mia (the dark bands) feeding grounds for dugongs, rays, turtles, & nurseries for invertebrates, fish, all attracting sharks, dolphins, and seabirds incl pelicans & emu that wander the shore ⚒️🧪🌊
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Lives cut short by whatever means always leave us wondering about lost potential (apart from any other kind of grief). Czechoslovak geologist & mineralogist Ludmila Slávíkova (1890–1943) died aged 53 at the hands of the most brutal regime imaginable ⚒️🧪🌊
www.geological-digressions.com/ludmila-slavikova-1890-1943/
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Hannah Robertson, the little celebrated wife of David Robertson an eminent 19th C Scottish marine biologist, was accomplished in the science of modern seaweeds, conchology & foraminifera. Acknowledgements of her expertise were few #Pioneering #Women www.geological-digressions.com/hanna-robertson-1826-1910/
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Thin section images of glauconitic pellet sand dredged from about 300 m on Chatham Rise, an elongate marine platform extending 1400 km east of South I. NZ. It is underlain by continental crust - a submerged part of Zelandia continent. Includes barnacles, foraminifera & echinoderm plates, spines. ⚒️🧪🌊
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Triassic rocks (grey cliffs = sandstone + diabase) thrust over Early-Mid Eocene sandstone (foreground) along Mokka Fiord, Axel Heiberg I. (next door to Ellesmere I, N Canada). The thrust itself (at base of slope) may be through Carboniferous-Permian evaporites (mostly covered by scree). ⚒️🧪
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Some delicate actively growing stalactites from Ruakuri Caves, formed in Oligocene limestones. Skinny varieties are probably few decades old; the larger a few centuries. Ruakuri is the Maori name for Two Dogs - refers to early Polynesian canines brought to NZ. On a visit w a couple of grandkids ⚒️🧪
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Front-yard spring! A cascade of colour, bird-song, and the odour of dung-spreading from nearby farms. ⚒️🧪😁
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Claudine Picardet's (1735-1820) translation of texts for scientists like Karl Scheele, Abraham Werner, Richard Kirwan (phlogiston) & maybe Lavoisier. She enabled and participated in the dissemination of 18th-19th C science to a broad audience.
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www.geological-digressions.com/claudine-picardet-1735-1820/
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Weathering patterns in basalt (a boulder lodged in beach sand) where oxidation of iron-bearing minerals (mainly amphiboles and pyroxenes) was controlled by earlier formed orthogonal joints. The dark grey bits are remnant non-altered basalt. Karioi Mt. Raglan, west coast NZ ⚒️🧪
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