@article{Trauth2013, author = {Trauth, Martin H.}, title = {TURBO2 - a MATLAB simulation to study the effects of bioturbation on paleoceanographic time series}, series = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology}, volume = {61}, journal = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology}, number = {12}, publisher = {Elsevier}, address = {Oxford}, issn = {0098-3004}, doi = {10.1016/j.cageo.2013.05.003}, pages = {1 -- 10}, year = {2013}, abstract = {Bioturbation (or benthic mixing) causes significant distortions in marine stable isotope signals and other palaeoceanographic records. Although the influence of bioturbation on these records is well known it has rarely been dealt systematically. The MATLAB program called TURBO2 can be used to simulate the effect of bioturbation on individual sediment particles. It can therefore be used to model the distortion of all physical, chemical, and biological signals in deep-sea sediments, such as Mg/Ca ratios and UK37-based sea-surface temperature (SST) variations. In particular, it can be used to study the distortions in paleoceanographic records that are based on individual sediment particles, such as SST records based on foraminifera assemblages. Furthermore. TURBO2 provides a tool to study the effect of benthic mixing of isotope signals such as C-14, delta O-18, and delta C-13, measured in a stratigraphic carrier such as foraminifera shells.}, language = {en} } @article{Trauth1998, author = {Trauth, Martin H.}, title = {TURBO : a dynamic-probabilistic simulation to studdy the effects of bioturbation on paleoceanographic time series}, year = {1998}, language = {en} } @article{TrauthLarrasoanaMudelsee2009, author = {Trauth, Martin H. and Larrasoa{\~n}a, Juan C. and Mudelsee, Manfred}, title = {Trends, rhythms and events in plio-pleistocene African climate}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2008.11.003}, year = {2009}, abstract = {We analyzed published records of terrigenous dust flux from marine sediments off subtropical West Africa, the eastern Mediterranean Sea, and the Arabian Sea, and lake records from East Africa using statistical methods to detect trends, rhythms and events in Plio-Pleistocene African climate. The critical reassessment of the environmental significance of dust flux and lake records removes the apparent inconsistencies between marine vs. terrestrial records of African climate variability. Based on these results, major steps in mammalian and hominin evolution occurred during episodes of a wetter, but highly variable climate largely controlled by orbitally induced insolation changes in the low latitudes.}, language = {en} } @article{FoersterDeocampoAsratetal.2018, author = {Foerster, Verena and Deocampo, Daniel M. and Asrat, Asfawossen and G{\"u}nter, Christina and Junginger, Annett and Kr{\"a}mer, Kai Hauke and Stroncik, Nicole A. and Trauth, Martin H.}, title = {Towards an understanding of climate proxy formation in the Chew Bahir basin, southern Ethiopian Rift}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {501}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2018.04.009}, pages = {111 -- 123}, year = {2018}, abstract = {Deciphering paleoclimate from lake sediments is a challenge due to the complex relationship between climate parameters and sediment composition. Here we show the links between potassium (K) concentrations in the sediments of the Chew Bahir basin in the Southern Ethiopian Rift and fluctuations in the catchment precipitation/evaporation balance. Our micro-X-ray fluorescence and X-ray diffraction results suggest that the most likely process linking climate with potassium concentrations is the authigenic illitization of smectites during episodes of higher alkalinity and salinity in the closed -basin lake, due to a drier climate. Whole-rock and clay size fraction analyses suggest that illitization of the Chew Bahir clay minerals with increasing evaporation is enhanced by octahedral Al-to-Mg substitution in the clay minerals, with the resulting layer charge increase facilitating potassium-fixation. Linking mineralogy with geochemistry shows the links between hydroclimatic control, process and formation of the Chew Bahir K patterns, in the context of well-known and widely documented eastern African climate fluctuations over the last 45,000 years. These results indicate characteristic mineral alteration patterns associated with orbitally controlled wet-dry cycles such as the African Humid Period (similar to 15-5 ka) or high-latitude controlled climate events such as the Younger Dryas (similar to 12.8-11.6 ka) chronozone. Determining the impact of authigenic mineral alteration on the Chew Bahir records enables the interpretation of the previously established pXRF-derived aridity proxy K and provides a better paleohydrological understanding of complex climate proxy formation.}, language = {en} } @article{MaslinPancostWilsonetal.2012, author = {Maslin, Mark A. and Pancost, Richard D. and Wilson, Katy E. and Lewis, Jonathan and Trauth, Martin H.}, title = {Three and half million year history of moisture availability of South West Africa evidence from ODP site 1085 biomarker records}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {317}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2011.12.009}, pages = {41 -- 47}, year = {2012}, abstract = {Ocean Drilling Program Site 1085 provides a continuous marine sediment record off southern South West Africa for at least the last three and half million years. The n-alkane partial derivative(13) C record from this site records changes in past vegetation and provides an indication of the moisture availability of SW Africa during this time period. Very little variation, and no apparent trend, is observed in the n-alkane delta C-13 record, suggesting stable long-term conditions despite significant changes in East African tectonics and global climate. Slightly higher n-alkane delta C-13 values occur between 3.5 and 2.7 Ma suggesting slightly drier conditions than today. Between 2.5 and 2.7 Ma there is a shift to more negative n-alkane delta C-13 values suggesting slightly wetter conditions during a similar to 0.2 Ma episode that coincides with the intensification of Northern Hemisphere Glaciation (iNHG). From 2.5 to 0.4 Ma the n-alkane delta C-13 values are very consistent, varying by less than +/- 0.5 parts per thousand and suggesting little or no long-term change in the moisture availability of South West Africa over the last 2.5 million years. This is in contrast to the long-term drying trend observed further north offshore from the Namib Desert and in East Africa. A comparison of the climate history of these regions suggests that Southern Africa may have been an area of long-term stability over the last 3.5 Myrs.}, language = {en} } @article{CohenCampisanoArrowsmithetal.2016, author = {Cohen, Andrew and Campisano, C. and Arrowsmith, J. Ram{\´o}n and Asrat, Asfawossen and Behrensmeyer, A. K. and Deino, A. and Feibel, C. and Hill, A. and Johnson, R. and Kingston, J. and Lamb, Henry F. and Lowenstein, T. and Noren, A. and Olago, D. and Owen, R. B. and Potts, R. and Reed, Kate and Renaut, R. and Sch{\"a}bitz, Frank and Tiercelin, J. -J. and Trauth, Martin H. and Wynn, J. and Ivory, S. and Brady, K. and Rodysill, J. and Githiri, J. and Russell, J. and F{\"o}rster, Verena and Dommain, Ren{\´e} and Rucina, S. and Deocampo, D. and Russell, J. and Billingsley, A. and Beck, C. and Dorenbeck, G. and Dullo, L. and Feary, D. and Garello, D. and Gromig, R. and Johnson, T. and Junginger, A. and Karanja, M. and Kimburi, E. and Mbuthia, A. and McCartney, T. and McNulty, E. and Muiruri, V. and Nambiro, E. and Negash, E. W. and Njagi, D. and Wilson, J. N. and Rabideaux, N. and Raub, T. and Sier, M. J. and Smith, P. and Urban, J. and Warren, M. and Yadeta, M. and Yost, C. and Zinaye, B.}, title = {The Hominin Sites and Paleolakes Drilling Project: inferring the environmental context of human evolution from eastern African rift lake deposits}, series = {Scientific Drilling}, volume = {21}, journal = {Scientific Drilling}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1816-8957}, doi = {10.5194/sd-21-1-2016}, pages = {1 -- 16}, year = {2016}, abstract = {The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered. We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012-2014 HSPDP coring campaign.}, language = {en} } @article{JungingerRollerOlakaetal.2014, author = {Junginger, Annett and Roller, Sybille and Olaka, Lydia A. and Trauth, Martin H.}, title = {The effects of solar irradiation changes on the migration of the Congo Air Boundary and water levels of paleo-Lake Suguta, Northern Kenya Rift, during the African Humid Period (15-5 ka BP)}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {396}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2013.12.007}, pages = {1 -- 16}, year = {2014}, abstract = {The water-level record from the 300 m deep paleo-lake Suguta (Northern Kenya Rift) during the African Humid Period (AHP, 15-5 ka BP) helps to explain decadal to centennial intensity variations in the West African Monsoon (WAM) and the Indian Summer Monsoon (ISM). This water-level record was derived from three different sources: (1) grain size variations in radiocarbon dated and reservoir corrected lacustrine sediments, (2) the altitudes and ages of paleo-shorelines within the basin, and (3) the results of hydro-balance modeling, providing important insights into the character of water level variations (abrupt or gradual) in the amplifier paleo-Lake Suguta. The results of these comprehensive analyses suggest that the AHP highstand in the Suguta Valley was the direct consequence of a northeastwards shift in the Congo Air Boundary (CAB), which was in turn caused by an enhanced atmospheric pressure gradient between East Africa and India during a northern hemisphere insolation maximum. Rapidly decreasing water levels of up to 90 m over less than a hundred years are best explained by changes in solar irradiation either reducing the East African-Indian atmospheric pressure gradient and preventing the CAB from reaching the study area, or reducing the overall humidity in the atmosphere, or a combination of both these effects. In contrast, although not well documented in our record we hypothesize a gradual end of the AHP despite an abrupt change in the source of precipitation when a decreasing pressure gradient between Asia and Africa prevented the CAB from reaching the Suguta Valley. The abruptness was probably buffered by a contemporaneous change in precession producing an insolation maximum at the equator during October. Whether or not this is the case, the water-level record from the Suguta Valley demonstrates the importance of both orbitally-controlled insolation variations and short-term changes in solar irradiation as factors affecting the significant water level variations in East African rift lakes.}, language = {en} } @article{HermannsTrauthMcWilliamsetal.2000, author = {Hermanns, Reginald L. and Trauth, Martin H. and McWilliams, Michael O. and Strecker, Manfred}, title = {Tephrochronologic Constraints on temporal Distribution of large Landslides in NW-Argentina}, year = {2000}, language = {en} } @article{AlonsoBookhagenCarrapaetal.2006, author = {Alonso, Ricardo N. and Bookhagen, Bodo and Carrapa, Barbara and Coutand, Isabelle and Haschke, Michael and Hilley, George E. and Schoenbohm, Lindsay M. and Sobel, Edward and Strecker, Manfred and Trauth, Martin H. and Villanueva, Arturo}, title = {Tectonics, climate and landscape evolution of the Southern Central Andes : the Argentine Puna Plateau and adjacent regions between 22 and 30°S}, isbn = {978-3-540- 24329-8}, year = {2006}, language = {en} } @article{BergnerStreckerTrauthetal.2009, author = {Bergner, Andreas G. N. and Strecker, Manfred and Trauth, Martin H. and Deino, Alan L. and Gasse, Francoise and Blisniuk, Peter Michael and Duehnforth, Miriam}, title = {Tectonic and climatic control on evolution of rift lakes in the Central Kenya Rift, East Africa}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2009.07.008}, year = {2009}, abstract = {The long-term histories of the neighboring Nakuru-Elmenteita and Naivasha lake basins in the Central Kenya Rift illustrate the relative importance of tectonic versus climatic effects on rift-lake evolution and the formation of disparate sedimentary environments. Although modem climate conditions in the Central Kenya Rift are very similar for these basins, hydrology and hydrochemistry of present-day lakes Nakuru, Elmenteita and Naivasha contrast dramatically due to tectonically controlled differences in basin geometries, catchment size, and fluvial processes. In this study, we use eighteen C-14 and Ar-40/Ar-39 dated fluvio-lacustrine sedimentary sections to unravel the spatiotemporal evolution of the lake basins in response to tectonic and climatic influences. We reconstruct paleoclimatic and ecological trends recorded in these basins based on fossil diatom assemblages and geologic field mapping. Our study shows a tendency towards increasing alkalinity and shrinkage of water bodies in both lake basins during the last million years. Ongoing volcano-tectonic segmentation of the lake basins, as well as reorganization of upstream drainage networks have led to contrasting hydrologic regimes with adjacent alkaline and freshwater conditions. During extreme wet periods in the past, such as during the early Holocene climate optimum, lake levels were high and all basins evolved toward freshwater systems. During drier periods some of these lakes revert back to alkaline conditions, while others maintain freshwater characteristics. Our results have important implications for the use and interpretation of lake sediment as climate archives in tectonically active regions and emphasize the need to deconvolve lacustrine records with respect to tectonics versus climatic forcing mechanisms.}, language = {en} } @article{Trauth2021, author = {Trauth, Martin H.}, title = {Spectral analysis in quaternary sciences}, series = {Quaternary science reviews : the international multidisciplinary research and review journal}, volume = {270}, journal = {Quaternary science reviews : the international multidisciplinary research and review journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2021.107157}, pages = {13}, year = {2021}, abstract = {Spectral analysis is a technique of time-series analysis that decomposes signals into linear combinations of harmonic components. Rooted in the 19th century, spectral analysis gained popularity in palaeoclimatology since the early 1980s. This was partly due to the availability of long time series of past climates, but also the development of new, partly adapted methods and the increasing spread of affordable personal computers. This paper reviews the most important methods of spectral analysis for palaeoclimate time series and discusses the prerequisites for their application as well as advantages and disadvantages. The paper also offers an overview of suitable software, as well as computer code for using the methods on synthetic examples.}, language = {en} } @article{EbertTrauth2015, author = {Ebert, Thomas and Trauth, Martin H.}, title = {Semi-automated detection of annual laminae (varves) in lake sediments using a fuzzy logic algorithm}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {435}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2015.05.024}, pages = {272 -- 282}, year = {2015}, abstract = {Annual laminae (varves) in lake sediments are typically visually identified, measured and counted, although numerous attempts have been made to automate this process. The reason for the failure of most of these automated algorithms for varve counting is the complexity of the seasonal laminations, typically rich in lateral fades variations and internal heterogeneities. In the manual counting of varves, the investigator acquired and interpreted flexible numbers of complex decision criteria to understand whether a particular simple lamination is a varve or not. Fuzzy systems simulate the flexible decision making process in a computer by introducing a smooth transition between true varve and false varve. In our investigation, we use an adaptive neuro fuzzy inference system (ANFIS) to detect varves on the basis of a digital image of the sediment. The results of the application of the ANFIS to laminated sediments from the Meerfelder Maar (Eifel, Germany) and from a landslide-dammed lake in the Quebrada de Cafayate of Argentina are compared with manual varve counts and possible reasons for the differences are discussed. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{AltenbachPflaumScheibeletal.1999, author = {Altenbach, Alexander V. and Pflaum, U. and Scheibel, Thomas R. and Thies, A. and Timm, M. and Trauth, Martin H.}, title = {Scaling percentages of benthic forminifera with flux rates of organic carbon}, year = {1999}, language = {en} } @article{TrauthDeinoStrecker2001, author = {Trauth, Martin H. and Deino, Alan and Strecker, Manfred}, title = {Response of the East African climate to orbital forcing during the Last Interglacial (130-117 kyr BP) and the early Last Glacial (117-60 kyr BP)}, issn = {0091-7613}, year = {2001}, language = {en} } @article{BorchardtTrauth2012, author = {Borchardt, Sven and Trauth, Martin H.}, title = {Remotely-sensed evapotranspiration estimates for an improved hydrological modeling of the early holocene mega-lake Suguta, northern Kenya Rift}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {361}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, number = {22}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2012.07.009}, pages = {14 -- 20}, year = {2012}, abstract = {The actual evapotranspiration is an important, but difficult to determine, element in the water balance of lakes and their catchment areas. Reliable data on evapotranspiration are not available for most lake basins for which paleoclimate reconstructions and modeling have been performed, particularly those in remote parts of Africa. We have used thermal infrared multispectral data for 14 ASTER scenes from the TERRA satellite to estimate the actual evapotranspiration in the 12,800 km(2) catchment of the Suguta Valley, northern Kenya Rift Evidence from sediments and paleo-shorelines indicates that, during the African Humid Period (AHP, 14.8 to 5.5 kyrs BP), this valley contained a large lake, 280 m deep and covering similar to 2200 km(2), which has now virtually disappeared. Evapotranspiration estimates for the Suguta Basin were generated using the Surface Energy Balance Algorithm for Land (SEBAL). Climate data required for the model were extracted from a high-resolution gridded dataset obtained from the Climatic Research Unit (East Anglia, UK). Results suggest significant spatial variations in evapotranspiration within the catchment area (ranging from 450 mm/yr in the basin to the north to 2000 mm/yr in more elevated areas) and precipitation that was similar to 20\% higher during the AHP than in recent times. These results are in agreement with other estimates of paleo-precipitation in East Africa. The extreme response of the lake system (similar to 280 m greater water depth than today, and a lake surface area of 2200 km(2)) to only moderately higher precipitation illustrates the possible sensitivity of this area to future climate change.}, language = {en} } @article{MaslinTrauth2009, author = {Maslin, Mark A. and Trauth, Martin H.}, title = {Plio-pleistocene East African pulsed climate variability and its influence on early human evolution}, isbn = {978-1-4020-9979-3}, year = {2009}, language = {en} } @article{FoersterAsratRamseyetal.2022, author = {Foerster, Verena and Asrat, Asfawossen and Ramsey, Christopher Bronk and Brown, Erik T. and Chapot, Melissa S. and Deino, Alan and D{\"u}sing, Walter and Grove, Matthew and Hahn, Annette and Junginger, Annett and Kaboth-Bahr, Stefanie and Lane, Christine S. and Opitz, Stephan and Noren, Anders and Roberts, Helen M. and Stockhecke, Mona and Tiedemann, Ralph and Vidal, Celine M. and Vogelsang, Ralf and Cohen, Andrew S. and Lamb, Henry F. and Schaebitz, Frank and Trauth, Martin H.}, title = {Pleistocene climate variability in eastern Africa influenced hominin evolution}, series = {Nature geoscience}, volume = {15}, journal = {Nature geoscience}, number = {10}, publisher = {Nature Publ. Group}, address = {London}, issn = {1752-0894}, doi = {10.1038/s41561-022-01032-y}, pages = {805 -- 811}, year = {2022}, abstract = {Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from similar to 620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (similar to 275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (similar to 60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens.}, language = {en} } @article{WeineltKuhntSarntheinLotichiusetal.2001, author = {Weinelt, Mara and Kuhnt, Wolfgang and Sarnthein-Lotichius, Johann Michael and Altenbach, Alexander V. and Costello, O. and Erlenkeuser, Helmut and Mathiessen, J. and Pflaumann, Uwe and Simstich, J. and Struck, J. and Thies, A. and Trauth, Martin H. and Vogelsang, E.}, title = {Paleoceanographic proxies in the northern North Atlantic}, isbn = {3-540-67231-1}, year = {2001}, language = {en} } @article{DulanyaCroudaceReedetal.2014, author = {Dulanya, Zuze and Croudace, Ian and Reed, Jane M. and Trauth, Martin H.}, title = {Palaeolimnological reconstruction of recent environmental change in Lake Malombe (S. Malawi) using multiple proxies}, series = {Water SA}, volume = {40}, journal = {Water SA}, number = {4}, publisher = {Water Research Commission}, address = {Pretoria}, issn = {0378-4738}, doi = {10.4314/wsa.v40i4.17}, pages = {717 -- 727}, year = {2014}, abstract = {Shallow inland water bodies in Malawi continue to be threatened by various environmental challenges despite their importance to the fisheries industry. Due to the complex interaction between natural and anthropogenic disturbances, disentangling the effect of the two may be a complicated process. The littoral zone of most water bodies is important in environmental reconstructions including pollution and lake level monitoring. This study used a littoral zone, transect-based approach employing multi-proxy palaeolimnological techniques to reconstruct recent environmental change (ca. 100 yrs.) in Lake Malombe in the Malawi Rift, East Africa. The results of the study could inform fisheries management in Lake Malombe, which experienced a catastrophic decline in fish stocks. Results support documentary evidence for the complete desiccation of the lake less than 100 years ago. Subsequently, there is evidence for accelerated eutrophication in the recent past. In light of these results, it is concluded that transect sampling approaches rather than relying on single core measurements, and the need for careful consideration of the types of proxy, are significant considerations in palaeoenvironmental reconstructions.}, language = {en} } @article{DongesDonnerTrauthetal.2011, author = {Donges, Jonathan and Donner, Reik Volker and Trauth, Martin H. and Marwan, Norbert and Schellnhuber, Hans Joachim and Kurths, J{\"u}rgen}, title = {Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {51}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1117052108}, pages = {20422 -- 20427}, year = {2011}, abstract = {Potential paleoclimatic driving mechanisms acting on human evolution present an open problem of cross-disciplinary scientific interest. The analysis of paleoclimate archives encoding the environmental variability in East Africa during the past 5 Ma has triggered an ongoing debate about possible candidate processes and evolutionary mechanisms. In this work, we apply a nonlinear statistical technique, recurrence network analysis, to three distinct marine records of terrigenous dust flux. Our method enables us to identify three epochs with transitions between qualitatively different types of environmental variability in North and East Africa during the (i) Middle Pliocene (3.35-3.15 Ma B. P.), (ii) Early Pleistocene (2.25-1.6 Ma B. P.), and (iii) Middle Pleistocene (1.1-0.7 Ma B. P.). A deeper examination of these transition periods reveals potential climatic drivers, including (i) large-scale changes in ocean currents due to a spatial shift of the Indonesian throughflow in combination with an intensification of Northern Hemisphere glaciation, (ii) a global reorganization of the atmospheric Walker circulation induced in the tropical Pacific and Indian Ocean, and (iii) shifts in the dominating temporal variability pattern of glacial activity during the Middle Pleistocene, respectively. A reexamination of the available fossil record demonstrates statistically significant coincidences between the detected transition periods and major steps in hominin evolution. This result suggests that the observed shifts between more regular and more erratic environmental variability may have acted as a trigger for rapid change in the development of humankind in Africa.}, language = {en} }