New Graduates!

We had the great pleasure of graduating two of our PhD students last weekend - hearty congratulations to Dr Marillo-Sialer (Estephany) and Bajo (Petra)!

Their PhD thesis were entitled

Matrix effects in LA-ICP-MS: Implications for in situ U-Pb geochronology

and

Geochemical investigations of Corchia speleothems: Implications for past climate change.

respectively. And here are the photos to prove it!

Left to right Jon, Estephany and Janet

Left to right Jon, Petra, Russ, and John

Nullarbor video

Well, it has taken a little while to get around to this but here is a short video with some highlights of our 2015 Nullarbor trip, and a little insight into the research that we are doing there. Have a look at our PNAS paper on Nullarbor pollen (I'm sure Kale will write a blog post all about it very soon!)

cheers, jon

The Million Year Old Monkey

Alongside and international team we have recently dated a species of fossil monkey found across the Caribbean to just over 1 million years old. The discovery was made after colleagues in America recovered a fossil tibia (shin bone) belonging to the species of extinct monkey Antillothrix bernensis from an underwater cave in Alttagracia Province, Dominican Republic.

The fossil was embedded in flowstone that we dated using the U-series technique to an age of 1.3±0.11 million years. Our paper, published in the Journal of Human Evolution, explains how 3D geometric morphometrics are used to confirm the fossil tibia does indeed belong to Antillothrix bernensis, a primate that we now know existed on Hispaniola relatively unchanged for over a million years. This work answers one of the great questions of bio-geography showing Antillothrix to have existed on Hispaniola morphologically unchanged for over a million years, changing the understanding of primate evolution in this region. Prior to these discoveries in Altragracia we knew almost nothing even though this species was first described back in 1977! 

Northern Australia - exploring the history of the monsoon

Here is a short video and some photos from our recent fieldwork in northern Australia looking at speleothem records of the Australian monsoon. The caves here are remote, hot (30 degrees), with 100% humidity, and difficult to work in but they are perfect sites for palaeoprecipitation studies. We have data loggers in some caves measuring drip rates, temperature and humidity and these are visited once a year to download the results. Stalagmite stable isotope records reveal millennial scale cycles in the intensity of the monsoon.

here are some photos from these beautiful  caves

Nullarbor 2015

The speleo team have just returned from another epic Nullarbor trip - 5000 kms and 6 caves in 10 days! Here are a few photos of some highlights. We have been working on Nullarbor speleogenesis for the past 10 years with some important papers on Pliocene climate coming soon!

Preparing to enter Decoration cave, northern Nullarbor. A very small hole in a very BIG landscape!

Camp Nullarbor night sky - WOW!

Climbing down into Thampana cave

A large Nullarbor cave, producing large speleothems. These are all Pliocene in age - a cave frozen in time.

A smaller cave with smaller speleothems, equally ancient.

Getting wet in Tasmania

We are just back from another caving trip - this time to Mole Creek in Tasmania. Unfortunately this coincided with a particularly cold spell, with snow down to 300m. We had to head underground to warm up!

An exciting and productive time was had by all though - here are some of our photos.


 
 

Keep an eye out for some images from our upcoming Nullarbor trip in June, then Riversleigh in July!

Evidence for global teleconnections in a speleothem from Sudwala Cave, S.A.

Analysis of a Pleistocene age speleothem collected from Sudwala Cave in South Africa’s Drakensberg mountains provides information about the climatic conditions associated with the onset and termination of stalagmite growth at the site.  An unusual combination of Raman and petrographic analysis has also allowed the identification of aragonite-calcite shifts potentially influencing the climate signals recorded. It has been possible to identify climatic conditions during the late deglaciation growth interval (13.85-12.79 ka) linking the region with both the Southern Hemispherically-Forced Antarctic Cold Reversal (14.1-12.8 ka), and the Younger Dryas (12.9-11.5 ka) event of Northern Hemisphere origin. Consequently, this study identifies Southern Africa as a key location for the investigation of global teleconnections during millennial-scale fluctuations. See Green et al., 2015. Quaternary Science Reviews

Riversleigh geochronology published

After a concerted effort over a good many years we have just finalised and published the first radiometric chronology for the Riversleigh World Heritage fossil mammal site in northwestern Queensland. This has been a difficult undertaking involving U-Pb geochronology of speleothems (associated with the fossil remains) containing  very small quantities of uranium. The new results provide an absolute radiometric chronology for the interpretation of faunal change through time, and links with palaeoclimate, where previous age estimation was entirely by biocorrelation. See Woodhead et al. Gondwana Research