Field Blog 2012 Wrap-up

Lack of  internet access in the field and available time the last week delayed the blog updates. I am not sure if this entry really counts as a "field blog" update, as I am sitting in a nice comfortable chair in my air conditioned family room at home, but I did want to provide a final update for this years field work.

 

June 11th through the 14th.   The morning of the 11th I wrapped up work on  "Big Mo", the large Prognathodon I discovered last year. We had  determined that collecting the specimen was just too ambitious for this year given our available time and crew size, so we have decided to rebury the specimen for collection in 2013. In the afternoon I shifted my focus to collecting other specimens found in previous years  and some from this season. I checked out the articulated vertebrae that Octavio had found the previous day. We had a student from the Methodist University in Luanda working with us this year, Ana Marques, and together we began to excavate the specimen. It turned out  to be the portion of the tail preserved in articulation was the section that bears a dorsal fleshy fluke and ventral bend.  There
were also a  number of isolated vertebrae from the anterior part of the tail surrounding it, but it appeared that this was the only portion of the animal  preserved; However, the next morning we decided to move more of the overburden and witihin five minutes of arriving on site we found what appears to be a relatively complete skull and artculated neck vertebrae and some isolated limb and girdle elements. Over the next two days and with the help of Ana, Ricardo, and Louis we recovered the entire specimen in two large jackets and a number of smaller ones.


Articulated portions of tail of russellosaurian mosasaur.


Skeleton of the new specimen.


Ricardo and Ana excavating tail block.


Ricardo has been largely focused on collecting plesiosaur specimens to augment the collection made in previous years, the material on which his Phd work is based. This year he was able to find additional specimens that allow us to definitively link a number of partial skeletons to specific taxa, giving us a better composite view of their anatomy and thus providing better data to determine their relationships. 


Ricardo excavating plesiosaur specimens.



Octavio has spent most of his time prospecting for dinosaurs in the terrestrial sediments near Bentiaba, finding a large number of bone fragments, some identifiable as sauropod limb elements. He also found yet another partial skull of the turtle Euclastes


Octavio and Ana excavating a partial Euclastes skull.

Partial Euclastes skull


On the 15th I drove Louis, Ricardo, Tyrone, and Ana to Lubango. Tyrone and Ana are finished with their field work for this year.  Louis and Ricardo will meet another member of our crew, Scott Myers, in Luanda on the 17th. Those three will then travel to the northern province of Cabinda to collect fossil and isotope samples and collect data to work out the stratigraphy and paleotemperature of these fossil bearing sediments. During the trip to Cabinda the crew collected numerous fish teeth, a complete skull of a turtle, a crocodile humerous, and a single vertebra of a small snake. A major focus of the Cabinda leg was to sample and examine the rocks and fossils of Cabinda that are relevant to human evolution and to the climatic and environmental history of Africa and the Tropics.  One of the most important topics in African paleontology is human evolution, documented mainly in East Africa.  There has been no Tropical lowland West African record of fossil primates until our discovery of a single tooth in Cabinda.  The importance of this find cannot be over estimated because it opens a new chapter that cannot be found elsewhere.  Additioanally, they sampled the rocks for magnetic and chemical analysis that will be used to understand climatic changes in the African Tropics associated with such global events as the onset of Antarctic glaciation, which provide an environmental context for human evolution.  Because the age of the rocks is imprecisely known, our work will have a major impact on this facet of science.

Cabinda localities. Jungle covers just about everything except the cliffs along the shore. These beach localities are the focus on our work here.


Ricardo and Scott on the largely vertical outcrops.

Louis and Scott collecting samples.


Turtle skull collected this year at Landana

Johanna Salminen (University of Helsinki, Finland) joined the team in Lubango on the 15th, returning with me to Bentiaba. She is a specialist in paleomagnetism. Throughout its history, the magentic polarity of the Earth has changed occassionally, and in some cases, as rocks are formed , they record that polarity. The dates of these polarity changes are now well known and the reversals can be used to correlate rocks over long distances. She collected rock samples from the Cretaceous sediments of Bentiaba and the K-Pg boundary section at Namibe to assist us with more precise dating of the rocks. Her colleague David Evans (Yale University) joined her in Lubango on the 27th to sample some of the oldest rocks in Angola to understand how the continent of Africa was formed.  Certain kinds of rock found within granite in Namibe and Huíla can show through their magnetic properties how the continent of Africa was originally assembled.  This is a fundamental scientific investigation and a direct outgrowth of discussions centered on our original work.

Johanna Salminen (University of Helsinki, Finland) with coring equipment.

Johanna sampling for paleomag at the K-Pg boundary in Namibe province.

Mike, Johanna, and Octavio at K-Pg boundary locality.


I spent the last few days at Bentiaba collecting the large Prognathodon specimen I found this year. Octavio collected a portion of a pterosaur wing. Although most of the specimen was left covered, it is the most complete found so far, consisting of at least three bones in articulation.   He also began to uncover one of the turtle specimens I found this year. When I found it, only a few peripheral plates were showing, weathering out of the hill. As Octavio began to uncover the specimen,
the costal ribs were found in place and it became apparent that we had a semi-articulated (and given previous experience here), a relatively complete skeleton. However, this was the last day in the field and we were running out of time, so this fossil was also reburied for excavation next year.


Pterosaur wing block. Top left is the defined block prior to plastering, top right is a detail of the bone that was weathering on the surace, and the bottom image is teh block just prior to removal.

Octavio digging an articulated turtle. This one will need to wait till next year due to time constraints.

 

During the last week in Angola, Octavio and I began managing the crating and shipping of the collection. Joined by student Claudio Raposo (Agostinho Neto University, Angola), we also took one day to go to the Turonian  locality of Iembe to collect the remains of a ninety million-year–old specimen of the turtle
previously named by Projecto PaleoAngola Angolachelys mbaxi.  This specimen was discovered by Johan Lindgren who joined us during our 2009 field season, and is the best preserved and most complete specimen found thus far.  Louis, Octavio and I had collected the skull block and part of the postcrania in 2011, but the large block collected by Octavio and I this year contains much of the postcrania.   On our return drive from Iembe, we  stopped to prospect sediments north of Barra do Dande and discovered another locality. It is interesting because it appears to contain a Campanian fauna and we found a couple of teeth of a rare durophageous mosasaur Globidens, that appears to be a different taxon from those reported elsewhere. The rest of the crew joined us in Luanda mid-week to finish the shipping prepartation that includes the collections made in 2011 and 2012 field seasons.


Removing the final block of the 2009 Angolachelys specimen.


Octavio and I talking to the students about fossils at the school in Iembe, the type locality of Angolatitan, Angolasaurus, and Angolachelys.


Repacking crates in Luanda. 

Crates being prepared for shipment.

 

The crew left Luanda on the 30th of June.

 

  • The significance of the 6th Projecto PaleoAngola Field Expedition is that it built on previous fieldwork to expand into new directions that increase the impact and significance of Angola’s fossils.

    We located and collected significant 90-66 million-year-old specimens of mosasaurs, turtles, and plesiosaurs, including the discovery of new species, and continued to build the finest collection of these kinds of fossils in the world.

    We sampled and examined the rocks and fossils of Cabinda that are relevant to human evolution and to the climatic and environmental history of Africa and the Tropics.  

    We sampled the rocks that record of Earth’s magnetic field as a means of pinpointing the extinction event that killed dinosaurs, mosasaurs, and other extinct animals and to more precisely date the fossils from our other localities.  Over 100 magnetic samples were collected from Bentiaba and the K-Pg boundary section at Macala Chipati to define the precise timing of extinction and open the door to examining the processes of global extinction as reflected in the rocks and fossils of Angola.  We also sampled for the magnetic signal of the oldest rocks in Angola to understand how the continent of Africa was formed.  

    We sampled volcanic rocks to refine the ages of fossils and geologic events related to the formation of the continent of Africa and the landforms of Angola.  One of the surprising discoveries of Projecto PaleoAngola is the extent of volcanic activity evidenced by 85 million-year-old lavas in Namibe.  We have sampled these for age determination and chemical analyses that will help define the formation of the Atlantic Ocean and the coast of Angola.

    We engaged Angolan students and continued our outreach activities in Angola and globally.  Projecto PaleoAngola was joined in the field by two Angolan students, one from Angola Methodist University and one from Agostinho Neto University.   We endeavor to make the project accessible through our web presence (PaleoAngola.org) including our field blog and blog posting on the Southern Methodist University website (smu.edu).  We distributed PaleoAngola coloring books (by LS filmes with Esso Angola support) in Cabinda and a presentation was made to the school in Iembe in Bengo Province.  On June 12, a press conference organized by Liga Nacional dos Amigos de 4 de Abril was held in Namibe and attended by the vice-governor of the province.

    We look forward to receiving the shipments of the fossil and rock samples to the US and Portugal for stabilization, extraction from matrix, and laboratory investigations.  Fieldwork is the stage of research in which samples are gathered.  In the laboratory, samples are converted into real data and into museum-quality study and display specimens.  This phase tests hypotheses proposed in the objectives of our field work.  It is the phase in which the story is made known and usable on a broad scale.

 


The field team for the 2012 Projecto PaleoAngola Field Expedition included the following participants:

Louis L. Jacobs (Southern Methodist University, USA)
Octávio Mateus (FCT, UNL, Portugal)
Michael J. Polcyn (Southern Methodist University, USA)
Scott Myers (Southern Methodist University, USA)
Ricardo Araújo (Southern Methodist University, USA)
Ana Soraya Marques (Angola Methodist University, Angola)
Claudio Raposo (Agostinho Neto University, Angola)
Tyrone Rooney (Michigan State University, USA)
Johanna Salminen (University of Helsinki, Finland)
David Evans (Yale University, USA)

Funding for the field season was provided by Vida Foundation, Esso Angola through the Liga Nacional dos Amigos de 4 de Abril, the Institute for the Study of Earth and Man at Southern Methodist University, The Saurus Institute, and Yale University.