Palaeomagnetism and the Deccan Trap volcanism

The results of palacomagnetic studies made on the Deccan Traps by various workers are reviewed in the light of the recent palaeomagnetic data on these rocks and the general geological information. It is suggested that: (a) the earlier altitude-polarity classification of the Deccan Traps, suggesting that the flows below the general elevation of 2000±200 feet above mean sea level are of reversed magnetic polarity while those above this horizon are normal, is not without exceptions; (b) the geomagnetic field reversed its polarity several times during the eruption of these lavas; (c) the Deccan Trap eruptions probably consisted of several phases of volcanicity over a protracted period; and (d) the phases of Deccan Trap volcanism, the phases of Himalayan upheaval, and the northward drift of the Indian landmass were rather concrescent events.     

The mid-Cretaceous super plume, carbon dioxide, and global warming

Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. We developed a carbonate-silicate cycle model to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. We find that CO2 emissions resulting from super-plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern pre-industrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering-rate formulations, this would cause a global warming of from 2.8 to 7.7 degrees C over today's global mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8 degrees C to mid-Cretaceous warming. Thus, the combined effects of paleogeographic changes and super-plume related CO2 emissions could be in the range of 7.6 to 12.5 degrees C, within the 6 to 14 degrees C range previously estimated for mid-Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20% of the mid-Cretaceous increase in atmospheric CO2.     

Evaluation of the four potential Cretaceous-Paleogene (K-Pg) boundaries in the Nanxiong Basin based on evidences from volcanic activity and paleoclimatic evolution

Determining the location of the Cretaceous-Paleogene(K-Pg) boundary in terrestrial strata is highly significant for studying the evolution of terrestrial ecosystems at the end of the Cretaceous(especially the extinction of non-avian dinosaurs). At present, research on terrestrial K-Pg boundaries worldwide is concentrated in the middle and high latitudes, such as North America and Northeast China. Although many studies have also been carried out in the Nanxiong Basin, located at low latitudes(which has become the standard for dividing and comparing the continental K-Pg stratigraphy in China), many researchers have proposed four possible boundaries from different perspectives. Therefore, the exact location remains to be determined. In this study, the total mercury(Hg) content, environmental magnetism, geochemistry, and other parameters for the samples collected near the four boundaries were determined and compared with existing records. Results indicated that: 1) The total Hg content significantly increased in the upper part of the Zhenshui Formation and Pingling part of the Shanghu Formation with sharp fluctuations. As per latest dating results of Deccan Traps, the significantly high Hg value was attributed to the Deccan Traps eruption. Boundary 1 was located in the middle of the Hg anomaly interval, which was consistent with the relationship between the global K-Pg boundary and time of volcanic eruption. 2) The reconstructed paleoclimate evolution curve revealed that the red sediments in the basin recorded the late Maastrichtian warming event(66.2 Ma). Regarding the relationship between the four boundaries and this warming event, only boundary 1 was found to be closest to the real K-Pg boundary of the Nanxiong Basin.     

The Global Warming Debate: A Review of the State of Science

A review of the present status of the global warming science is presented in this paper. The term global warming is now popularly used to refer to the recent reported increase in the mean surface temperature of the earth; this increase being attributed to increasing human activity and in particular to the increased concentration of greenhouse gases (carbon dioxide, methane and nitrous oxide) in the atmosphere. Since the mid to late 1980s there has been an intense and often emotional debate on this topic. The various climate change reports (1996, 2001) prepared by the IPCC (Intergovernmental Panel on Climate Change), have provided the scientific framework that ultimately led to the Kyoto protocol on the reduction of greenhouse gas emissions (particularly carbon dioxide) due to the burning of fossil fuels. Numerous peer-reviewed studies reported in recent literature have attempted to verify several of the projections on climate change that have been detailed by the IPCC reports.The global warming debate as presented by the media usually focuses on the increasing mean temperature of the earth, associated extreme weather events and future climate projections of increasing frequency of extreme weather events worldwide. In reality, the climate change issue is considerably more complex than an increase in the earth’s mean temperature and in extreme weather events. Several recent studies have questioned many of the projections of climate change made by the IPCC reports and at present there is an emerging dissenting view of the global warming science which is at odds with the IPCC view of the cause and consequence of global warming. Our review suggests that the dissenting view offered by the skeptics or opponents of global warming appears substantially more credible than the supporting view put forth by the proponents of global warming. Further, the projections of future climate change over the next fifty to one hundred years is based on insufficiently verified climate models and are therefore not considered reliable at this point in time.     

古今气候略论

自2009年入冬以来北半球经受了创记录的严寒侵袭,联合国IPCC报告的权威性受到质疑。地球气候变化趋向陷入纷争的境地。从地质学和考古学的视角,以更长的时间周期去认识和了解气候变化规律和成因机制,或许对将来气候的长期预报有所启示。地球在漫长的演化史中经历了以千万年计的＂地质气候旋回＂、千百年计的＂史前气候周期＂及近现代以百年计的＂世纪气候波动＂。不同级次的周期均为内在自然因素所制约,CO2含量在地球演化史中趋于波动下降过程,当代的CO2浓度和气温均处于地质史的低点。人类活动可能在百年尺度内存在对气候和生态环境的影响。自20世纪初开始至今近百年升温趋向中,令人关注的是在中国曾有1941年、1969年、2009~2010年之交极度低温的出现,＂低温节点＂时距约为30~40年,似与海洋存在数十年为变化周期之说相近。由此引发对人为因素导致持续增温的质疑。2009年入冬以来的严寒是否为近百年升温波动周期的终结抑或只是次级的突变因素所致,尚有待观察。但自然因素主导的周期波动规律不可逆转,不能被未经实证而被夸大了的＂人为因素＂所左右。     

Mode of eruption of the deccan trap basalts

The Deccan Trap basalts have long been considered to be products of fissure eruptions and the dykes intruding them have been supposed to represent the fissures of eruption. However, the question of the mode of eruption of Deccan Trap lavas seems to need more careful consideration in view of the features brought to light by detailed field work in Western Maharashtra. Detailed studies of dykes suggest that majority of the dykes could not have acted as feeders as previously supposed. When examined in detail the basalt flows have more often been found to have only a limited lateral extent and are not always quite horizontal. Thin irregular flows with ropy surfaces, dipping in different directions and piled up into a chaotic mass are frequently met with, indicating eruption from local vents of the central type. Volcanic vents are found at a number of widely separated localities. All this suggests that many lavas are products of central type of volcanicity. However, central type of volcanoes would be inadequate to account for the vast amounts of lavas, and as the known dykes are not likely to have acted as feeders, and dykes still remain to be reported from large portions of the Deccan Trap area, the question of how the lavas came to the surface largely remains unanswered. Extensive beds of volcanic breccia traceable over a few miles and upto 50 feet thick are met with. As such extensive beds are more likely to be associated with fissure cruptions the question arises whether these fissure eruptions were accompanied by considerable explosive activity.     

Palaeogeography,geomorphological setting and groundwater possibilities in the Deccan Traps of Western Maharashtra

Deccan Traps are the most extensive geological formations of Deccan Peninsula with the exception of only the metamorphic and igneous complex of Archaean age. Based on their mode of emplacement, geomorphic setting and hydrogeological behaviour over an area of about 5,000 sq. km the authors have classified the Deccan Traps of western Maharashtra into 3 groups, namely, (1) The Deccan Traps of Dhulia district, characterised by numerous dolerite dykes, (2) Areally extensive trap flows of Sholapur and Osmanabad districts resulting from slow and quiescent type of flood eruption occupyng the gently undulating terrain, and (3) the traps of Kolaba, Thana and Bombay-Poona regions characterised by intertrappean sediments, dolerite dykes and volcanic ash beds, indicative of violent outbursts resulting in the Sahyadri geomorphologic unit. The groundwater possibilities in the three groups are to a great extent governed by the nature and constitution of the individual flows. The massive traps with their fracture porosities, the vesicular traps with their minutely interconnected and partly filled vesicles and the intertrappen sediments with their primary porosities play a decisive role in determining the groundwater possibilities in them. In Dhulia district the dolerite dykes to a great extent control the movement of groundwater, and success or otherwise of the well field area depends very much upon its location with reference to adjacent dykes. Areally extensive thick vesicular traps with their gentle dips towards east, in Sholapur district, have to be explored for possible artesian conditions in the downdip directions of the trappean units to be tapped. In the case of Poona, Thana and Kolaba districts, exploratory drilling based on geophysical data (to delineate the nature and extent of water bearing horizons) has to be resorted to. It is, therefore, imperative to sub-divide at this stage Taylor’s Single Unit of Deccan Trap Groundwater Province into 3 Sub-Provinces, based on geomorphological, geological and geohydrological setting in the region of western Maharashtra of the present investigation.     

Climate tipping-point potential and paradoxical production of methane in a changing ocean

The global warming potential of methane (CH₄) is about 30 times stronger than that of carbon dioxide (CO₂) over a century timescale. Methane emission is hypothesized to have contributed to global climate change events and mass extinctions during Earth’s history. Therefore, the study of CH₄ production processes is critically important to the understanding of global climate change. It has been a dogma that biogenic CH₄ detectable in the oceans originates exclusively from the anaerobic metabolic activity of methanogenic archaea in hypoxic and anoxic environments, despite reports that many oxic surface and near-surface waters of the world’s oceans are CH₄-supersaturated, thereby rendering net sea-to-air emissions of CH₄. The phenomenon of CH₄ production in oxic marine waters is referred to as the “ocean methane paradox”. Although still not totally resolved, recent studies have generated several hypotheses regarding the sources of CH₄ production in oxic seawater. This review will summarize our current understanding of the importance of CH₄ in the global climate and analyze the biological processes and their underpinning mechanisms that lead to the production of CH₄ in oxic seawater environments. We will also tentatively explore the relationships of these microbial metabolic processes with global changes in climate and environment.     

Geological and geophysical investigations on Deccan Traps

Volcanic rocks occupy considerable regions in the western portion of India, attaining a maximum thickness of 7000′ near Igatpuri. These rocks are essentially basaltic in nature and are generally referred to as plateau basalts. An attempt has been made in this paper to present some results of geological and geophysical investigations carried out in the Deccan Traps. Three areas (Ajanta - Long. 75″41′ -75° 45′ E, Lat. 20° 32′ - 20° 35′ 15″ N, 18 sq. miles in area; Ellora -Long. 75″ 11′ - 75° 16′ E, Lat. 20° 1′ - 20° 9′ N, 80 sq. miles in area; and Chincholi - Long. 77° 22′ - 77° 30′ E, Lat. 17° 22′ -17° 30′ N, 50 sq. miles in area) have been chosen for this study because of their geological setting. A large number of field specimens have been collected for petrographic study. This is supplemented by examination of microsections and chemical analyses of a few traps. In the Chincholi area where the trap overlies the granites, limestones seem to intervene in between trap and granites. With a view to estimate the possible thickness of the limestone beds, the distribution of intensity of magnetic field in a portion of the area has been studied with a magnetometer. Magnetic susceptibilities in case of few specimens have also been studied. Elastic constants of Deccan Traps have been determined for fifty specimens, employing the Wedge Method. These are further correlated with textural features and porosity values. Such an integrated geological and geophysical investigation on Deccan Traps is bound to reveal some interesting results.     

Alkaline rocks of the deccan traps

Recent investigations on the Deccan Traps reveal many new findings of alkaline rocks more commonly occurring as minor intrusions than as lava flows. In comparison to the vast extent of the Deccan Traps, the alkaline rocks are negligible in their volume and are confined to tectonic belts in parts of Western India. The rocks exhibit no systematic variation in their petrographical and chemical characters thereby suggesting that they were not derived from a primary alkali olivine-basalt magma. The possibility of derivation of alkaline magma locally along the rift zones is proposed. Some of the alkaline rocks are shown to have been formed due to the effective role of volatiles in bringing dissociation of feldspar in certain cases, and alkali metasomatism in others. The syntexis of the pre-Deccan Trap carbonate rocks along the Narmada rift zone is also responsible for some occurrences.     

Late Pleistocene to Holocene eruptive activity of Pico de Orizaba,Eastern Mexico

The Late Pleistocene to Holocene eruptive history of Pico de Orizaba can be divided into 11 eurptive episodes. Each eruptive episode lasted several hundred years, the longest recorded being about 1000 years (the Xilomich episode). Intervals of dormancy range from millenia during the late Pleistocene to about 500 years, the shortest interval recorded in the Holocene. This difference could reflect either changes in the volcano's activity or that the older stratigraphic record is less complete than the younger. Eruptive mechanisms during the late Pleistocene were characterized by dome extrusions, lava flows and ash-and-scoria-flow generating eruptive columns. However, in Holocene time plinian activity became increasingly important. The increase in dacitic plinian eruptions over time is related to increased volumes of dacitic magma beneath Pico de Orizaba. We suggest that the magma reservoir under Pico de Orizaba is stratified. The last eruptive episode, which lasted from about 690 years bp until ad 1687, was initiated by a dacitic plinian eruption and was followed by effusive lava-forming eruptions. For the last 5,000 years the activity of the volcano has been gradually evolving towards such a trend, underlining the increasing importance of dacitic magma and stratification of the magma reservoir. Independent observations of Pico de Orizaba's glacier early this century indicate that some increase in volcanic activity occurred between 1906 and 1947, and that it was probably fumarolic.     

Mantle-derived spinel lherzolite xenoliths from the deccan volcanic province (India): Implications for the thermal structure of the lithosphere underlying the deccan traps

Petrography, mineral and host-rock chemistry of the mantle-derived spinel lherzolite xenoliths in the nephelinites of Kutch, a late variant of the Deccan Traps province, India, are reported. The xenoliths register equilibration temperatures between 920° ± 70°C and 1060° ± 50°C and an ascent time between 19 and 168 days. Representing a palaeogeotherm of minimum heat flow between 60 and 70 mW/m², the xenoliths possibly came from the oceanic lithosphere under the Deccan field, following the Cretaceous-Eocene fragmentation of Gondwanaland.     

European summer temperature response to annually dated volcanic eruptions over the past nine centuries

The drop in temperature following large volcanic eruptions has been identified as an important component of natural climate variability. However, due to the limited number of large eruptions that occurred during the period of instrumental observations, the precise amplitude of post-volcanic cooling is not well constrained. Here we present new evidence on summer temperature cooling over Europe in years following volcanic eruptions. We compile and analyze an updated network of tree-ring maximum latewood density chronologies, spanning the past nine centuries, and compare cooling signatures in this network with exceptionally long instrumental station records and state-of-the-art general circulation models. Results indicate post-volcanic June–August cooling is strongest in Northern Europe 2 years after an eruption (?0.52?±?0.05 °C), whereas in Central Europe the temperature response is smaller and occurs 1 year after an eruption (?0.18?±?0.07 °C). We validate these estimates by comparison with the shorter instrumental network and evaluate the statistical significance of post-volcanic summer temperature cooling in the context of natural climate variability over the past nine centuries. Finding no significant post-volcanic temperature cooling lasting longer than 2 years, our results question the ability of large eruptions to initiate long-term temperature changes through feedback mechanisms in the climate system. We discuss the implications of these findings with respect to the response seen in general circulation models and emphasize the importance of considering well-documented, annually dated eruptions when assessing the significance of volcanic forcing on continental-scale temperature variations.     

Climate change inferred from analysis of borehole temperatures: First results from Alberta Basin,Canada

High quality temperature measurements have been made to depths of 30 to 220 m at 42 sites in 62 observational hydrogeological wells in Alberta. The temperature profiles commonly show near-surface inversions with a minimum temperature at depths of 30 to 50 m. Thermal modelling suggests a surface temperature history with warming reaching 2°C over the past 30 to 60 years. Recent climate warming evident from the analysis of the air temperature data in the region seems to provide at least a partial explanation of the increased ground temperatures. A sudden increase of the surface ground temperature caused by land clearing may be the other explanation, although modelling of such a sudden increase can only explain the observed temperature-depth data if the onset of such warming is 20–30 years old, which is in disagreement with the history of land development in the studied area. The effect of near-surface inversions of the temperature profiles also has been observed in the forested areas. The above support the climate based effect. The superposition of the climatic effect and man-made activity effect upon the ground warming is a very complicated process calling for considerably more research.     

Mafic alkalic magmatism in central Kachchh,India: a monogenetic volcanic field in the northwestern Deccan Traps

Magmatism in Kachchh, in the northwestern Deccan continental flood basalt province, is represented not only by typical tholeiitic flows and dikes, but also plug-like bodies, in Mesozoic sandstone, of alkali basalt, basanite, melanephelinite and nephelinite, containing mantle nodules. They form the base of the local Deccan stratigraphy and their volcanological context was poorly understood. Based on new and published field, petrographic and geochemical data, we identify this suite as an eroded monogenetic volcanic field. The plugs are shallow-level intrusions (necks, sills, dikes, sheets, laccoliths); one of them is known to have fed a lava flow. We have found local peperites reflecting mingling between magmas and soft sediment, and the remains of a pyroclastic vent composed of non-bedded lapilli tuff breccia, injected by mafic alkalic dikes. The lapilli tuff matrix contains basaltic fragments, glass shards, and detrital quartz and microcline, with secondary zeolites, and there are abundant lithic blocks of mafic alkalic rocks. We interpret this deposit as a maar-diatreme, formed due to phreatomagmatic explosions and associated wall rock fragmentation and collapse. This is one of few known hydrovolcanic vents in the Deccan Traps. The central Kachchh monogenetic volcanic field has >30 individual structures exposed over an area of ∼1,800 km² and possibly many more if compositionally identical igneous intrusions in northern Kachchh are proven by future dating work to be contemporaneous. The central Kachchh monogenetic volcanic field implies low-degree mantle melting and limited, periodic magma supply. Regional directed extension was absent or at best insignificant during its formation, in contrast to the contemporaneous significant directed extension and vigorous mantle melting under the main area of the Deccan flood basalts. The central Kachchh field demonstrates regional-scale volcanological, compositional, and tectonic variability within flood basalt provinces, and adds the Deccan Traps to the list of such provinces containing monogenetic- and/or hydrovolcanism, namely the Karoo-Ferrar and Emeishan flood basalts, and plateau basalts in Saudi Arabia, Libya, and Patagonia.     

Paleomagnetic study of a vertical sequence of deccan traps from Jabalpur

The palaeomagnetism of a vertical sequence of Deccan traps ranging in elevation from 1750 to 2900 ft. along the eastern margins of the Deccan trap exposures near Jabalpur, has been studied. Eleven different flows were sampled at approximately 100 ft. elevation interval. Nine flows at elevations between 2150 and 2900 ft. showed normal polarization with up dip. The mean direction for these siving unit weight to each flow was,D=343°E andI=28°(up). Two flows at elevations between 1740 and 2000 ft. showed intermediate directions with down dip. It appears that the latter corresponds to a zone of actual field reversal which has been encountered at several locations on the territory of the Deccan traps. The mean directions of the nine upper flows give a reliable estimate of the palaeosecular variation of the geomagnetic field during the period of normal polarity. The mean directions obtained from vertical sequences of traps studied from different localities are compared for estimating the amount of continental drift that might have taken place during the period of main Deccan trap activity. Correlation of magnetic directions of flows from various localities indicates that the geomagnetic field reversal at about 2000 ft. elevation can be traced over a large territory of the traps.     

A test of terminal Mesozoic “catastrophe”

Terminal Mesozoic “catastrophe”-type extinction models that advocate synchronous marine and terrestrial extinctions spanning short time intervals (a few days up to a few millennia) have a common foundation: the simultaneous terminations of geological ranges of some taxa of marine CaCO₃-producing microplankton (and possibly the dinosaurs) at the end of the Cretaceous. Gartner and McGuirk [1] propose a new catastrophe theory that at the end of the Cretaceous fresh-brackish water from the Arctic Ocean spread over the surface of the world's oceans, causing global cooling, aridity, and the extinctions. Like other catastrophe models, this one also fails to address the possibility of hiatus control of ranges at the end of the Cretaceous; a well documented, seemingly nearly universal hiatus of variable and unknown duration separates Cretaceous and Tertiary strata. Documented terminal Cretaceous marine regression (perhaps 10 times more rapid than a typical regression according to Cooper [8] would have caused terrestrial erosion and stripping away of the latest Cretaceous stratigraphic record, thus truncating geological ranges along a seemingly planar datum. The terminal Cretaceous marine CaCO₃ dissolution event would have had the same effect on ranges of marine planktonic CaCO₃-producing microplankton (the event was a shallow-water phenomenon). The simultaneous terminations of geological ranges is thus possibly the result of hiatus control, and the terminal Cretaceous “catastrophe” an illusion. Attempts to use Cretaceous-Tertiary transition floras to support global cooling at the time of the extinctions are not based on sound stratigraphic foundations; realistic paleobotanical-climatic inferences can only be based on the precise correlation of the Cretaceous-Tertiary contact in marine and terrestrial stratigraphic sections, and these correlations have not been made with sufficient precision to support catastrophe theory. The much used “across the Cretaceous-Tertiary boundary” glosses over ignorance of the true terminal Cretaceous scenario, lost forever in most places by the destruction of the terminal Cretaceous stratigraphic record. For now, stable isotope paleotemperature data from marine strata that can be dated radiometrically provide the most reliable estimates of the Cretaceous-Tertiary transition climate; Boersma et al. [5] indicate global warming of deep and shallow oceans “across” the contact (and not surficial cooling only as is required by the spillover model). Older much-cited climate inferences based on leaf physiognomy are suspect in light of Dolph and Dilcher's [23] work that shows little correlation between leaf physiognomy and climate.     

Dykes around Dadiapada,broach district,Gujarat

The basaltic lava flows of the Deccan Traps in the Dadiapada area are traversed by abundant dykes trending mostly in ENE to WSW direction. The density of the dykes distribution is 2 to 3 per mile. They vary in size from a few feet to 300 feet in width and some can be traced for many miles. Some of the dolerites contain quartz in considerable amounts and it is significant to find micropegmatite texture in them indicating their tholetitic nature.     

The sylhet traps,their tectonic history,and their bearing on problems of indian flood basalt provinces

Recent studies of the Sylhet Traps (? Jurassic) and the overlying Cretaceous-Tertiary sedimentary cover in the southern part of the Khasi Hills, Shillong Plateau in Assam have led to a reconstruction of the tectonic history of the area since Jurassic times; a clear picture regarding the nature of volcanism has also emerged. The history begins with effusion of tholeiitic basalts, apparently through E-W fissures developed in the peneplaned crystalline basement. One of these fractures became a fault (the Raibah fault) along which the northern non-volcanic block moved up relative to the southern block experiencing volcanism. The fault was active during and after the volcanism till Upper Cretaceous times. The sequence of eruption was as follows: (1) tholeiitic basalts, (2) minor alkali basalts (nepheline tephrite), (3) tholeiitic basalts, (4) localised explosive effusion of minor rhyolites and acid tuffs, and (5) tholeiitic basalts. Neither feeder dykes nor volcanic vents have been noted in the Sylhet Traps. There are no agglomerates among the basic flows; the fragmental rocks are actually flow breccias. The formation of the various structures such as flow breccias, layering and flow folds in many of the basalt flows are thought to have been controlled by the angle of slope and the rate of flow. Thus, the Sylhet Trap flood basalts are characterised by quiet effusion through linear fissures. The effusion was followed by a dyke phase, intruding also along E-W fractures, expecially in the monoclinally bent southern portion; the subsequent tectonic history of the area is also characterised by relative uplift and downsinking of different basement blocks. It is concluded that in the Shillong Plateau uparching of the basement led to fracturing, effusion of basalts apparently along some zones of fissuring along which differential vertical movement of basement blocks was taking place. In the light of the foregoing conclusions, available data on the tectonics of the Rajmahal and the Deccan Traps are examined; both these flood basalt provinces have suffered broadly similar tectonic histories as the Sylhet Traps. The various features of flood basalts, viz., large extent, huge thickness, subaerial nature, a post-volcanic dyke phase are interpreted as a consequence of fusion of the Upper Mantle, development of tensional fractures eruptions apparently along fractures between adjoining basement blocks undergoing differential uplift.     

CLIMATE HISTORY INFERRED FROM BOREHOLE TEMPERATURES, DATA FROM THE CZECH REPUBLIC

The knowledge of the present-day underground temperatures may be important in the assessments of the past climate change. The method of inversion of the temperature-depth records into the ground surface temperature history is briefly introduced by showing an example of synthetic data and illustrated by a review of existing results obtained from the inversion of temperature logs measured in holes in the Czech Republic. Underground temperatures observed in holes of the depth of at least 1000–1500 m seem to confirm the preinstrumental climate pattern of the past several thousand years. Most of shallower temperature records (500–800 m) revealed general warming of climate followed the Little Ice Age of the 17–18th centuries and a pronounced increase of the soil temperatures by at least 1 K since the beginning of this century.