Magmas 524 Magnetic anomalies 554 Magnetic field 759 Magnetic methods 818 Magnetic properties 473 Magnetic susceptibility 538 Magnetosphere 878 Major elements 520 Mammalia 1,681 Mandibulata 1,731 Mantle 770 Mapping 3,826 Maps 2,844 Maps and charts 418 Marine atmospheres 404 Marine biology 3,362 Marine deposits 3,859 Marine environment 5,960 Marine geology 1,301 Marine installations 768 Marine sedimentation 1,110 Marine sediments 4,148 Marine transportation 569 Mars 1,294 Mars (planet) 1,375 Mass balance 3,540 Mass movements 4,237 Mass movements (geology) 4,245 Mass spectra 920 Mass transfer 871 Mathematical methods 1,674 Mathematical models 8,749 Measurement 3,452 Measuring instruments 2,136 Mechanical properties 2,218 Mechanical tests 538 Mechanism 662 Meetings 1,883 Melting 2,490 Meltwater 5,533 Mesozoic 3,128 Metabolism 420 Metal ores 577 Metals 5,287 Metamorphic rocks 1,705 Metamorphism 937 Metamorphism (snow) 503 Meteorites 1,436 Meteorological data 1,605 Meteorological factors 1,538 Meteorological instruments 534 Meteorology 6,433 Meteorology--Instruments 672 Meteorology--Maps and charts 557 Meteorology--Models 890 Methane 1,316 Methods 1,265 Microbiology 2,045 Microclimatology 479 Microelement content 534 Microfossils 5,267 Microorganisms 904 Microstructure 637 Microwave methods 910 Microwaves 1,865 Migration 521 Military engineering 392 Military facilities 712 Military geology 516 Military operation 641 Mineral composition 1,546 Mineral exploration 516 Mineralogy 893 Mineral resources 402 Minerals 636 Mining 1,453 Miocene 803 Miospores 1,823 Mires 965 Mitigation 1,613 Mixing 672 Models 11,293 Modern 1,207 Modern analogs 410 Moisture 1,937 Moisture transfer 463 Molecular energy levels 494 Molecular structure 1,128 Mollusca 1,233 Monitoring 3,137 Monsoons 503 Moraines 4,397 Morphology 1,511 Mosses 570 Motor vehicles 548 Mountain glaciers 1,885 Mountains 2,603 Mountain soils 526 Movement 1,199 Mudflows 642