Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

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Has the Earth’s sixth mass extinction already arrived?

The revolution that wasn't: a new interpretation of the origin of modern human behavior.

CHAPTER 1. INTRODUCTION TO KARST. 1.1 Definitions. 1.2 The Relationship Between Karst And General Geomorphology And Hydrogeology. 1.3 The Global Distribution Of Karst. 1.4 The Growth Of Ideas. 1.5 Aims Of The Book. 1.6 Karst Terminology. CHAPTER 2. THE KARST ROCKS. 2.1 Carbonate Rocks And Minerals. 2.2 Limestone Compositions And Depositional Facies. 2.3 Limestone Diagenesis And The Formation Of Dolomite. 2.4 The Evaporite Rocks. 2.5. Quartzites And Siliceous Sandstones. 2.6 Effects Of Lithologic Properties Upon Karst Development. 2.7 Interbedded Clastic Rocks. 2.8 Bedding Planes, Joints, Faults And Fracture Traces. 2.9 Fold Topography. 2.10 Paleokarst Unconformities. CHAPTER 3. DISSOLUTION: CHEMICAL AND KINETIC BEHAVIOUR OF THE KARST ROCKS. 3.1 Introduction. 3.2 Aqueous Solutions And Chemical Equilibria. 3.3 The Dissolution Of Anhydrite, Gypsum And Salt. 3.4 The Dissolution Of Silica. 3.5 Bicarbonate Equilibria And The Dissolution Of Carbonate Rocks In Normal Meteoric Waters. 3.6 The S-O-H System And The Dissolution Of Carbonate Rocks. 3.7 Chemical Complications In Carbonate Dissolution. 3.8 Biokarst Processes. 3.9 Measurements In The Field And Lab Computer Programs. 3.10 Dissolution And Precipitation Kinetics Of Karst Rocks. CHAPTER 4. DISTRIBUTION AND RATE OF KARST DENUDATION. 4.1 Global Variations In The Solutional Denudation Of Carbonate Terrains. 4.2 Measurement And Calculation Of Solutional Denudation Rates. 4.3 Solution Rates In Gypsum, Salt And Other Non-Carbonate Rocks. 4.4 Interpretation Of Measurements. CHAPTER 5. KARST HYDROLOGY. 5.1 Basic Hydrological Concepts, Terms And Definitions. 5.2 Controls On The Development Of Karst Hydrologic Systems. 5.3 Energy Supply And Flow Network Development. 5.4 Development Of The Water Table And Phreatic Zones. 5.5 Development Of The Vadose Zone. 5.6 Classification And Characteristics Of Karst Aquifers. 5.7 Applicability Of Darcy's Law To Karst. 5.8 The Fresh Water/Salt Water Interface. CHAPTER 6. ANALYSIS OF KARST DRAINAGE SYSTEMS. 6.1 The 'Grey Box' Nature Of Karst. 6.2 Surface Exploration And Survey Techniques. 6.3 Investigating Recharge And Percolation In The Vadose Zone. 6.4 Borehole Analysis. 6.5 Spring Hydrograph Analysis. 6.6 Polje Hydrograph Analysis. 6.7 Spring Chemograph Interpretation. 6.8 Storage Volumes And Flow Routing Under Different States Of The Hydrograph. 6.9 Interpreting The Organisation Of A Karst Aquifer. 6.10 Water Tracing Techniques. 6.11 Computer Modelling Of Karst Aquifers. CHAPTER 7. SPELEOGENESIS: THE DEVELOPMENT OF CAVE SYSTEMS. 7.1 Classifying Cave Systems. 7.2 Building The Plan Patterns Of Unconfined Caves. 7.3 Unconfined Cave Development In Length And Depth. 7.4 System Modifications Occurring Within A Single Phase. 7.5 Multi-Phase Cave Systems. 7.6 Meteoric Water Caves Developed Where There Is Confined Circulation Or Basal Injection Of Water. 7.7 Hypogene Caves: (A) Hydrothermal Caves Associated Chiefly With Co2. 7.8 Hypogene Caves: (B) Caves Formed By Waters Containing H2s. 7.9 Sea Coast Eogenetic Caves. 7.10 Passage Cross-Sections And Smaller Features Of Erosional Morphology. 7.11 Condensation, Condensation Corrosion, And Weathering In Caves. 7.12 Breakdown In Caves. CHAPTER 8. CAVE INTERIOR DEPOSITS. 8.1 Introduction. 8.2 Clastic Sediments. 8.3 Calcite, Aragonite And Other Carbonate Precipitates. 8.4 Other Cave Minerals. 8.5 Ice In Caves. 8.6 Dating Of Calcite Speleothems And Other Cave Deposits. 8.7 Paleo-Environmental Analysis Of Calcite Speleothems. 8.8 Mass Flux Through A Cave System: The Example Of Friar's Hole, W.Va. CHAPTER 9. KARST LANDFORM DEVELOPMENT IN HUMID REGIONS. 9.1 Coupled Hydrological And Geochemical Systems. 9.2 Small Scale Solution Sculpture - Microkarren And Karren. 9.3 Dolines - The 'Diagnostic' Karst Landform? 9.4 The Origin And Development Of Solution Dolines. 9.5 The Origin Of Collapse And Subsidence Depressions. 9.6 Polygonal Karst. 9.7 Morphometric Analysis Of Solution Dolines. 9.8 Landforms Associated With Allogenic Inputs. 9.9 Karst Poljes. 9.10 Corrosional Plains And Shifts In Baselevel. 9.11 Residual Hills On Karst Plains. 9.12 Depositional And Constructional Karst Features. 9.13 Special Features Of Evaporite Terrains. 9.14 Karstic Features Of Quartzose And Other Rocks. 9.15 Sequences Of Carbonate Karst Evolution In Humid Terrains. CHAPTER 10.THE INFLUENCE OF CLIMATE, CLIMATIC CHANGE AND OTHER ENVIRONMENTAL FACTORS ON KARST DEVELOPMENT. 10.1 The Precepts Of Climatic Geomorphology. 10.2 The Hot Arid Extreme. 10.3 The Cold Extreme: 1 Karst Development In Glaciated Terrains. 10.4 The Cold Extreme: 2 Karst Development In Permafrozen Terrains. 10.5 Sea Level Changes, Tectonic Movement And Implications For Coastal Karst Development. 10.6 Polycyclic, Polygenetic And Exhumed Karsts. CHAPTER 11. KARST WATER RESOURCES MANAGEMENT. 11.1 Water Resources And Sustainable Yields. 11.2 Determination Of Available Water Resources. 11.3 Karst Hydrogeological Mapping. 11.4 Human Impacts On Karst Water. 11.5 Groundwater Vulnerability, Protection, And Risk Mapping. 11.6 Dam Building, Leakages, Failures And Impacts. CHAPTER 12. HUMAN IMPACTS AND ENVIRONMENTAL REHABILITATION. 12.1 The Inherent Vulnerability Of Karst Systems. 12.2 Deforestation, Agricultural Impacts And Rocky Desertification. 12.3 Sinkholes Induced By De-Watering, Surcharging, Solution Mining And Other Practices On Karst. 12.4 Problems Of Construction On And In The Karst Rocks - Expect The Unexpected! 12.5 Industrial Exploitation Of Karst Rocks And Minerals. 12.6 Restoration Of Karstlands And Rehabilitation Of Limestone Quarries. 12.7 Sustainable Management Of Karst. 12.8 Scientific, Cultural And Recreational Values Of Karstlands.

Karst Hydrogeology and Geomorphology

A review of quartz optically stimulated luminescence characteristics and their relevance in single-aliquot regeneration dating protocols

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.

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Genetic history of an archaic hominin group from Denisova Cave in Siberia

Whose teeth? Reply

Connections between the Levant and the Balkans in the late Middle Pleistocene: Archaeological findings from Velika and Mala Balanica Caves (Serbia).

The dosimetric response of neutron irradiated human tooth enamel has been investigated using electron paramagnetic resonance (EPR) dosimetry Continuous energy fast neutrons of mean energy less than 450 keV were produced from the McMaster University 3 MV KN Van de Graaff accelerator employing a thick lithium target via 7 Li(p,n) 7 Be interaction Prior to its use for various experiments, the gamma dose contamination of the neutron beams was determined at the selected proton beam energies using the tissue-equivalent proportional counter (TEPC) The neutron sensitivity (/Gy-100 mg) of human tooth enamel remained constant for various mean neutron energies ranging from 167 to 450 keV Similarly, the EPR signal intensity remained independent of the neutron dose rate variation from 05 to 24 Gy/h

Electron paramagnetic resonance dose response studies for neutron irradiated human teeth

Samples taken from four different faults at a depth of 400 m show no sign of a bulk heating higher than about 350°C (heating time 15 min) during fault activities. Besides radiation defects, the aggregation behavior of iron ions studied by electron spin resonance (ESR) can be used as a measure for the thermal history of fault gouge material. Clusters of iron ions are formed as a result of the heating of biotite and feldspar minerals. They give broad (ΔB ≈ 200 mT) and intense signals in the ESR spectra. Mn2+ point defects react very sensitively to crushing of the samples, while relatively isolated and coupled Fe3+ point defects in the feldspars do not.

ESR signals from clusters of iron ions as indicators of the thermal history of fault gouge

This work marks the fist application of Photoluminescence (OSL- Optical Stimulated Luminescence) in Colombia. Photo luminescence method allows the determination of the age of burial of materials with a range from 6 to 800 000 years under optimal conditions; the method is really important for the study of diverse quaternary deposits. Detailed field work, aerial photo analysis and stratigraphic study of the study area were completed with emphasis on the stoneline, a regional horizon of clastic accumulation. The aim of this work was to achieve a better understanding of the paleoenvironmental conditions when the surface formations of the area were originated, as well as the evolution of the highlands and uplift of the Central Cordillera. The first ages obtained in Colombia by photoluminescence correspond to the stoneline: 30 900 ± 4 500, 24 100 ± 3 800 and 18 900 ± 2 300 years for the horizons FSO 07-2, FSO 16-2A and FSO 19-2 respectively. These ages belong to the Last Pleniglacial, erosive period of dry and cold conditions with intermittent rain and scarce vegetation. Deposits below the stoneline where dated in 53 400 ± 5 900, 66 700 ± 14 000 and 36 000 ± 4 900 years at the horizons FSO 06-3, FSO 16-3 and FSO 19-3 respectively, which indicates they were formed during the humid period from 60 000 to 28 000 years BP.

W.J. Rink

Papers

Whose teeth? Reply

Connections between the Levant and the Balkans in the late Middle Pleistocene: Archaeological findings from Velika and Mala Balanica Caves (Serbia).

Electron paramagnetic resonance dose response studies for neutron irradiated human teeth

ESR signals from clusters of iron ions as indicators of the thermal history of fault gouge

Datación por fotoluminiscencia de la stoneline y otras formaciones superficiales del llano de ovejas, cordillera central, antioquia