Dead Sea Deep Cores

News: Curiosity on the Way to Mars, p. 455 Forum: Was Pre–Twentieth Century Sea Level Stable?, p. 455 Meeting: Observing Terrestrial Gamma Ray Flashes, p. 457 Meeting: Radiation Belt Research, p. 457 AGU Bookshelf: Mountain Rivers Revisited, p. 458 Research Spotlight: Quake Visualization, Ice Stream Flow, and More, p. 464 VOLUME 92 NUMBER 49 6 DECEMBER 2011 Dead Sea Deep Cores: A Window A Library of Georeferenced Into Past Climate and Seismicity Photos From the Field The area surrounding the Dead Sea was The location of the Dead Sea Basin, at the A picture is worth a thousand of words, only to the owner of the photos (i.e., private the locus of humankind’s migration out of boundary between the Arabian- Sahara des- and every day hundreds of scientists, stu- mode). This privacy control feature warrants Africa and thus has been the home of peo- erts and the Mediterranean climate zones, dents, and environmentally aware citizens priority use of the field photos by the photo ples since the Stone Age. For this reason, enhances its sensitivity to the starkly con- are taking field photos to document their contributors for their own research activities understanding the climate and tectonic his- trasting (arid versus temperate) climate and observations of rocks, glaciers, soils, forests, if needed. Photo contributors with “private” tory of the region provides valuable insight hydrological conditions of these regions. wetlands, croplands, rangelands, livestock, photos are regularly notified and encouraged into archaeology and studies of human his- Moreover, because the formation of the and birds and mammals, as well as impor- to make their photos “public.” An interac- tory and helps to gain a better picture of basin is a consequence of tectonic activity tant events such as droughts, floods, wild- tive graphical user interface is also available future climate and tectonic scenarios. along the Dead Sea Transform Fault [Ben- fires, insect emergences, and infectious dis- for users to interpret and classify field pho- The deposits at the bottom of the Dead Avraham, 1997], its sediments preserve the ease outbreaks. Where are those field photos tos (e.g., various land cover types); to enter Sea are a geological archive of the environ- history of seismic activity [e.g., Marco et al., stored? Can they be shared in a timely fash- field notes; and to build thematic databases mental conditions (e.g., rains, floods, dust 1996; Migowski et al., 2004], which are impor- ion to support education, research, and the from the photos, ranging from crop-specific storms, droughts) during ice ages and warm tant to hazard assessments of the region. leisure activities of citizens across the world? themes (e.g., paddy rice, sugarcane, and win- ages, as well as of seismic activity in this Two sites were cored (Figure 1) as part of the What are the financial and intellectual costs if ter wheat) to general land cover types (e.g., key region. An International Continental Sci- ICDP-funded venture into the Dead Sea. One those field photos are lost or not shared? forests, cropland). After selection of specific entific Drilling Program (ICDP) deep drill- was in the deepest basin in the center of the Recently, researchers at the Univer- photos (e.g., by time, keywords, geographical ing project was performed in the Dead Sea Dead Sea, at a water depth of 297 meters, and sity of Oklahoma developed and released domains, and land cover types) a user can between November 2010 and March 2011. recovered cores down to about 460 meters the Global Geo-Referenced Field Photo download both photos and associated data The project was funded by the ICDP and below the sediment surface. The second site, Library (hereinafter referred to as the Field in several formats (e.g., as comma- separated agencies in Israel, Germany, Japan, Norway, in several meters of water, recovered cores Photo Library; http:// www .eomf .ou .edu/ values (.csv), an Excel file (.xls(x)), a zipped Switzerland, and the United States. Drilling down to roughly 350 meters below the sedi- photos/), a Web-based data portal designed Keyhole Markup Language file (.kmz), and was conducted using the new Large Lake ment surface. For another picture of the drill- for researchers and educators who wish to an ArcGIS Esri shapefile (.shp)). These files Drilling Facility (Figure 1), a barge with a ing facility, see Figure S1 in the online sup- archive and share field photos from across can then be used for spatial analyses in geo- drilling rig run by DOSECC, Inc. (Drilling, plement to this brief report (http:// www .agu the world, each tagged with exact position- graphical information systems (e.g., ArcGIS), Observation and Sampling of the Earth’s .org/ journals/ eo/ v092/ i049/ 2011EO490001/ ing data (Figure 1). The data portal has a image processing (e.g., Exelis’s Environment Continental Crust), a nonprofit corporation 2011EO490001 _suppl .pdf). simple user interface that allows people to for Visualizing Images (ENVI) and Inter- dedicated to advancing scientific drilling upload, query, and download georeferenced graph’s Earth Resources Data Analysis System worldwide. The main purpose of the proj- Preliminary Results and Future Plans. field photos in the library. (ERDAS)), and Google Earth. ect was to recover a long, continuous core The idea behind this is simple: Changes The Field Photo Library was initially set to provide a high resolution record of the Opening and description of the recovered in land use and land cover have significant up to aid the effort to track changes in land paleoclimate, paleoenvironment, paleoseis- cores occurred in June and October 2011 at impacts on weather, climate, hydrology, biodi- use and land cover from airborne and space- micity, and paleomagnetism of the Dead Sea the GFZ German Research Centre for Geo- versity, and food security across various spa- borne remote sensing. Georeferenced field Basin. With this, scientists are beginning to sciences in Potsdam, Germany. The cores tial and temporal scales. Tracking land use and photos are used as in situ or ground refer- piece together a record of the climate and have two main sedimentary facies: (1) marly land cover changes through georeferenced ence data for algorithm development and seismic history of the Middle East during the sequences of millimeter-thick laminated lay- photos gives a visual picture (ground truth) to validation of remote sensing data products. past several hundred thousand years in mil- ers of inorganic aragonite and silty detritus numerical data, allowing scientists, policy mak- Many research projects have carried out lennial to decadal to annual time resolution. composed mainly of calcite and quartz and ers, and the public the opportunity to visual- field expeditions, often repeatedly in the (2) sequences of rock salt and marls (see Fig- ize the evolution of landscapes at small scales. same study areas, without a means of shar- Regional Setting and the Collection of Cores ure S2 in the online supplement). The arago- Thus, these photos are invaluable for docu- ing field photo data. By using the Field Photo nite and detritus laminations reflect deposi- menting land use and land cover changes. Library, researchers can contribute to a spa- The Dead Sea, located in the Dead Sea tion in dry (summer) and wetter and stormy tially and temporally extensive database of Basin at the lowest continental elevation on (winter) seasons, respectively. Moreover, the Using the Library detailed ground reference information that Earth (currently 425 meters below mean sea aragonite provides the potential to establish can be accessed from any location in the level), is a terminal lake that evolved from a calendar chronology, through uranium- Through its privacy control feature, photo world. For example, a user can query and previous water bodies that occupied the tec- thorium dating and oxygen isotope stratigra- contributors to the Field Photo Library can download thousands of georeferenced field tonic depressions along the Dead Sea Trans- phy [e.g., Haase- Schramm et al., 2004; Torfs- designate whether their photos are publicly form Fault. The history of these water bodies tein et al., 2009]. Gypsum layers are scattered available (i.e., public mode) or available Field Photo Library cont. on page 454 commenced with the late Neogene ingres- throughout, indicating sustained dry periods. sion (~6–3 million years ago) of the Mediter- Provisional interpretation of the lithology of ranean Sea into the valley, forming a back- the core through time strongly indicates that water called the Sedom Lagoon. A series of the salt layers are deposited during arid inter- terminal lakes (lakes with no outlets) filled glacials and that long salt-free marly inter- the basin after the disconnection of the vals are wetter glacials, together spanning an lagoon from the Mediterranean [Stein, 2001]. interval of about 200,000 years. This interval The lakes received their water from two bleeds into the time frame of the interglacial major sources: calcium chloride brines that labeled in oxygen isotope records of ocean evolved from the ancient remnant solution sediments as marine isotope stage 7. of the Sedom Lagoon, and freshwater runoff. An important discovery is a mud-free The limnology of the lakes was controlled layer of rounded pebbles, possibly reflect- by the regional hydrology, which reflects the ing a beach deposit, more than 230 meters climate conditions in the watershed [Stein deep in the core taken from the deep basin, et al., 1997]. Over the past several hundred deposited at an age provisionally estimated thousand years the lakes expanded and con- to be the last interglacial. The pebble layer tracted with changing climate conditions due overlies about 40 meters of mainly salt, and to the supply of freshwater. The modern Dead Sea is the latest of these series of lakes.

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