The process of discovery in science can be as fascinating to follow as a sporting event: if we knew how it was going to end we would be much less likely to watch. The Rising Star Expedition has the drama but not the finality, fortunately!, of a sporting event where there is a final score. The goal lines are constantly moving and when one hill is finally scaled there is an ever higher hill yet to climb. Discovery leads to yet more discovery. The RSE has certainly shown us that. Of course one has to be invested in the team to really care about the outcome but for any fossil hunter this is as good as it gets. A fossil hunter is really interested in understanding history much in the way a CSI agent is interested in solving a crime. The tools are remarkably similar but the work conditions here are pretty challenging!
Evidently the original expedition was arranged with the expectation that the first stage, the original goal-line, was one of retrieving some bones lying or protruding from the surface of a cavern floor deep within a cave system.
A few weeks work, the bones would be retrieved and then the long slow process of examination, reconstruction and filling the geological context would commence. Easy, right? Well, the expedition has reached the end of its planned time in the field and the main goal of retrieval has turned into something like triple overtime. The number of bones in this chamber has far exceeded the wildest imaginations of the expedition organizers, so much so that they finally had to call an end to the archaeological dig with a significant number of bones yet to be retrieved.
So what have they recovered so far? They have retrieved and cataloged over 1000 hominid fossils!! Many of these fossils are small fragments of bone rather than entire bones though some large pieces of bones have apparently been retrieved. Nonetheless it is apparent that these fossils represent the remains of multiple individuals. It sounds as if there are large numbers of fossils remaining at the site that will be retrieved in future expeditions. Expedition leaders have implied there are so many more fossils there that it will take decades to fully explore this site and retrieve all the fossils.
Clearly the members of the research team are becoming increasing confident that this site has the potential to become one of the most significant fossil hominid sites in the world. While details about the fossils themselves are understandably scant, the tweets and blogs that expedition members have posted have allowed the rest of the world to enjoy the process of discovery. What started as a hope that a few bones could be retrieved has turned into a flood of fossils and raised even more questions. Answers to most of our questions will have to wait until detailed analyses can be performed.
To get a feel for what it has been like to be in these caves, one caver, Rich Hunter, has written a particularly poetic and haunting account (The Journey into Darkness) of what it is like to descend into this dark abyss which I highly recommend.
What will happen next?
Expedition leaders are a bit overwhelmed by the enormous load of fossils and are going to need time to find ways to share data with the community. I expect we will see some updates along the way leading up to the publication of the initial results. I am sure that future digs at the site will be arranged and more caves will explored. Apparently the place where these bone were found has been visited by modern cavers in the past but they apparently did not realize the significance of what they saw and did not report the bones. This find certainly raises awareness of locations such as this and it would not be surprising if more such locations are discovered.
Speculation about the geological context of the fossils
A few of my friends have asked me a question that you may have pondered as well: If these bones have been here for so long why were they found lying on the surface and not embedded in rock or under layers of sediments like in other caves in the world? I wondered that myself but a clue to that was revealed this week. The bone may well have been encased in rock and have simply had the rock around them dissolved revealing the fossils. The cave is apparent very wet and though we haven’t been told directly the sediments on the floor would seem to be in the process of erosion rather than added sedimentation. The fossils could have been encased in a former cave that cave has re-eroded in relatively recent times revealing the bones. There well could be many bones left in the walls and the rock below the floor of the cave that will take years to extract. If my speculation is correct then these bone are not simply from a couple of people who fell into a pit and died and their bones where left lying there since. All indications are that the bones are fragmented, in a fossilized state (not as bones that would have sat on the surface would be even after very long periods of time) and so these bones are being revealed to world having been stored in rock for as yet unknown ages. Analysis of the rocks and fossils will give us a clearer picture in the years ahead.
To keep updated on the Rising Star Expedition, read the National Geographic blog and follow Lee Berger @LeeRBerger, and the hashtag #risingstarexpedition.
Dr. John Hawks has written a post about the expedition to explain what they know, what they don’t know and why they can’t tell us everything that they do. It is a very helpful discussion of how discovery works and when information can or can’t be shared. http://newswatch.nationalgeographic.com/2013/11/20/rising-star-hominid-what-we-know-and-dont-know/