Jaco H. Baas

⚒️NEW PAPER ALERT:
Softgrounds: substrates controlled by sediment gravity flows and the evolution of deep-water trace fossils
With Yuxuan Wang, Paul Wignall, Jeff Peakall & Simon Poulton
(forthcoming GeolSoc SP)

Where exactly is this on Anglesey?

Video stills of the heads of selected CaCO3 flows. (A) 15% low-density turbidity current, (B) 25% low-density turbidity current, (C) 53% high-density turbidity current, (D) 55% high-density turbidity current, (E) 58% mud flow and (F) 59% slide. Dashed lines in (C) and (D) show density interfaces in high-density turbidity currents. Arrow in (E) points to lip region of mud flow. Scale bar is 100 mm long.

Our new paper....
"Coming to light: How effective are sediment gravity flows in removing fine suspended carbonate from reefs?" led by
@makingripples.bsky.social along with William Hewitt & James Hendry is out now as #OpenAccess in The Depositional Record.

Enjoy!

doi.org/10.1002/dep2...

@earth-science.bsky.social ⚒️NEW PAPER ALERT: "Coming to light: How effective are sediment gravity flows in removing fine suspended carbonate from reefs?" with
@lokier.bsky.social @bangoruniversity.bsky.social

@earth-science.bsky.social ⚒️ Dear
@sedimentology.bsky.social student members,
I encourage you to apply for the 11th International Summer School of Sedimentology, held on July 4-12, 2025, in Wales and hosted by @makingripples.bsky.social, Meg Baker, Dei Huws & @lokier.bsky.social.

.

NEW PAPER ALERT: Silt matters in sandy bedform dynamics! Led by Sjoukje de Lange and soon to be published in
AGU's Water Resources Research.

NEW PAPER ALERT: Continuing the reinvention of sole marks, and extending their use beyond palaeoflow reconstruction. Led by Jeff Peakall and soon out in the journal Sedimentology.

@earth-science.bsky.social
NEW PAPER ALERT: How does sediment gravity flow mobility vary for mixtures of weakly & strongly cohesive clay types? Counterintuitively, adding small amounts of strongly cohesive clay enhances mobility... Led by the amazing Megan Baker and to be published in AGU monograph

doi.org/10.1002/dep2...

@earth-science.bsky.social New paper submitted: An extension of a classical method for predicting water-surface wave properties from wave ripples in the geological record. Led by Jonathan Malarkey.⚒️🌊 @jsedimentology.bsky.social

@earth-science.bsky.social ⚒️ Some places left for ECRs, but be quick! Price reduced to £156 p/p, following generous sponsoring from the International Association of Sedimentologists.

@earth-science.bsky.social ⚒️ New paper alert: Marine redox dynamics and biotic response to the mid-Silurian Ireviken Extinction Event in a mid-shelf setting, led by Yuxuan Wang (Leeds)

Result from the Kimmeridge Clay #paleostream!

@earth-science.bsky.social ⚒️ New manuscript submitted: "Integrating transitional-flow signatures into hybrid event beds: Implications for hybrid-flow evolution on a submarine lobe fringe", led by Piotr Łapcik (Krakow, Poland). An extended facies model for hybrid event beds!

@earth-science.bsky.social Part 2 of what MS Bing AI picture creator makes of "deep-marine turbidity current". It is getting worse! (left: 2 months ago, right: today)

Picture from the Abu Dhabi sabkha showing a flat surface with a poorly developed polygonal pattern. The edges of polygons are curled upward and inward.

Desiccation polygons in thin microbial mats. As mats dehydrate and contract, the edges of polygons roll inwards to produce characteristic open dishes. These edges are particularly susceptible to erosion and transport - acting to ‘seed’ new mats if deposited in a suitable environment. #SabkhaSaturday

Picture showing my shoe on a boulder with wave ripple marks

A boulder at the playground with some very nice wave ripple marks. ⚒️ #UrbanGeology

If you are a MSc or PhD Student working on volcanic processes in the sedimentary record, I encourage you to present your results during the 9th @sedsonline.bsky.social Student Webinar that is held on 24th April. Recruitment is open by 15th March: docs.google.com/forms/d/e/1F... #Seds_Online

I reply with a picture of the axial plane crenulations

@earth-science.bsky.social ⚒️ New publication alert:
Manning, Chassagne & Parsons - Cohesive Sedimentary System: Dynamics and Deposits
A great collection of papers on 'sticky' sediment. Free to download: www.frontiersin.org/research-top....

Source Rocks Of Earth's First Real Continents Have Been Uncovered
astrobiology.com/2024/02/sour...
#astrobiology #exoplanet #geology

Crossbedded? fabric in the 1.7 billion year old Yavapai Schist in central Arizona USA. Boot for scale. Dark and light interlaminated metasandstone with wavy subhorizontal lamina/lamina sets, truncated and downlappping laminae.

Crossbedded ? fabric in the 1.7 billion year old Yavapai Schist in central Arizona USA. Erosion surfaces, wavy, truncated, and down lapping lamina sets, fining-upward ? successions, fine- and coarse-grained interbeds. Boot for scale.

Crossbedded ? metasandstone in the 1.7 billion year old Yavapai Schist in central Arizona USA, with cobble-sized rip-up class, finer- and coarser-grained interbeds, truncated, onlapping and down lapping lamina sets. Boot for scale.

Crossbedded ? metasandstone in the 1.7 billion year old Yavapai Schist in central Arizona USA. Meter-scale hummocky crossbedding with rip-up clasts, truncated lamina, finer- and coarser-grained interbeds. Boot for scale.

Outcrop of metasandstone in the 1.7 billion year old Yavapai Schist in central Arizona USA that has some intriguing relict sedimentary structures, including trough and hummocky cross-stratification and cobble-sized rip-up clasts. The huge hummocky crossbeds, with rip-ups, could be a tsunamite. 🧪⚒️

The BSRG Aberystwyth Fieldtrip focuses on the latest insights in submarine gravity flow research, and is open to post/graduate students and Early Career Researchers from the UK and across Europe👇

A tiny wee chloritoid star from the highest-grade rocks in the Northern Apennines (but still low grade), the Massa Unit: home of the very rare chloritoid + kyanite assemblage.

⚒️

New Sedimentology (Volume 71/Issue 2, February 2024) is now available: onlinelibrary.wiley.com/toc/13653091...

Museum display with flat fossils in a case beneath a model of a green, slimy-looking part fish, part salamander.

Close-up of the fossil, showing it's flat, wide head and scaly body.

Here's Elpistostege, a transitional "fishopod" with wrists and the ability to do pushups. Life-size model by Tyler Keillor, naturally. #FossilFriday 🧪⚒️

A dried mud puddle, with many randomly oriented needle shaped indentations. Fingers for scale.

Ice casts in mud.

Folded rocks, Eden, NSW, Australia ⚒️

Nice heavy mineral sedimentation patterns on the beach ⚒️

The real questions are: 6 (six) other whiteboards! Why do not need them? How big is your office? Weren't you told always to make backups?