geometry and physical properties of the socorro new mexico magma bodies analysis of multichannel seismic reflection profiles gathered by the consortium for continental reflection profiling cocorp constrains the geometry and material properties of a proposed magma body located within the rio grande rift a new spectral ratio method is used to find the reflectivities of the proposed midcrustal intrusion large and spatially variable reflectivities support the interpretation of the reflector as an intrusive molten magma complex modeling of the reflectivity suggests that in one location the intrusion took the form of several thin 30 to 40 m thick layers seismic wave attenuation within the rift s midcrust is low

nitrous oxide in the deep waters of the world s oceans we present a compilation and analysis of n2o data from the deep water zone of the oceans below 2000 m the n2o values show an increasing trend from low concentrations in the north atlantic ocean to high concentrations in the north pacific ocean indicating an accumulation of n2o in deep waters with time we conclude that the observed n2o accumulation is mainly caused by nitrification in the global deep water circulation system i e the conveyor belt hydrothermal and sedimentary n2o fluxes are negligible we estimate the annual n2o deep water production to be 0 3 0 1 tg despite the fact that the deep sea below 2000 m represents about 95 of the total ocean volume it contributes only about 3 16 to the global open ocean n2o production a rough estimate of the oceanic n2o budget suggests that the loss to the atmosphere is not balanced by the deep sea nitrification and pelagic denitrification therefore an additional source of 3 8 tg n2o yr 1 attributed to nitrification in the upper water column 0 2000 m might exist with a simple model we estimated the effect of changes in the north atlantic deep water nadw formation for deep water n2o the upper water n2o budget is not significantly influenced by variations in the n2o deep water formation however the predicted decrease in the nadw formation rate in the near future might lead to an additional source of atmospheric n2o in the range of about 0 02 0 4 tg yr 1 this anthropogenically induced source is small and it will be difficult to detect its signal against the natural variations in the annual growth rates of tropospheric n2o

distributions and sea to air fluxes of nitrous oxide in the coastal and shelf waters of the northwestern south china sea abstract nitrous oxide n 2 o in the coastal and shelf waters of the northwestern south china sea was determined during five campaigns carried out from 2006 to 2009 n 2 o distributions showed temporal fluctuations in both concentration and saturation in the coastal waters along the eastern hainan island highest mean surface n 2 o concentrations were observed in winter 10 44 1 45 nm 140 20 saturation and the lowest values 6 28 0 47 nm 110 8 1 saturation were observed in summer after a strong typhoon in the shelf region of the northwestern south china sea n 2 o concentrations varied from 5 51 to 7 74 nm with the saturation of 99 123 in august 2008 n 2 o distributions in the coastal and shelf waters of south china sea were influenced by complex interactions of several processes including land source input air sea exchanges in situ biological production and physical mixing n 2 o in the intermediate waters of the shelf region of the south china sea was formed mainly through nitrification n 2 o yield from nitrification was estimated to be 0 065 based on correlations of excess n 2 o versus apparent oxygen utilization and no 3 concentrations average sea to air n 2 o fluxes from the coastal waters were estimated to be 3 2 3 5 and 5 6 6 1 mol m 2 d 1 using the lm86 and w92 equation and sea to air n 2 o fluxes from the shelf region were 1 1 1 0 and 1 7 1 6 mol m 2 d 1 using the lm86 and w92 relationships respectively the coastal and shelf waters of the northwestern south china sea behaved as a net source of n 2 o to the atmosphere and n 2 o emission can be enhanced by either typhoon related upward mixing or strong air sea exchange

pollen stratigraphic evidence of human activity at dieng central java abstract the pollen stratigraphy of a small lake at 2000 m elevation in the dieng highlands of central java where a large hindu javanese religious center flourished from about 1250 to 700 b p indicates substantial and nearly continuous clearance of the montane forest since about 1350 b p a core to the base of organic sediments is 14 m long and has a basal date of 1340 b p a zone of abundant pollen of the weedy herb plantago major corresponds well in time with the occupation of the religious center after about 700 b p the pollen of secondary forest species shifted in composition suggesting a different pattern of vegetation use in the highlands in the mid 19th century european observers reported that the forest on the mountains at dieng was closed and mature but evidence in the pollen is lacking by the 1920s the expanding human population had stripped the landscape of trees and the first pollen of cultivated plants appears in the stratigraphy because of local protection and forest replanting trees have again increased on the steepest slopes and the pollen assemblage today differs in composition from the previous zones

spatial variability of turbulent mixing in the abyssal ocean ocean microstructure data show that turbulent mixing in the deep brazil basin of the south atlantic ocean is weak at all depths above smooth abyssal plains and the south american continental rise the diapycnal diffusivity there was estimated to be less than or approximately equal to 0 1 x 10 4 meters squared per second in contrast mixing rates are large throughout the water column above the rough mid atlantic ridge and the diffusivity deduced for the bottom most 150 meters exceeds 5 x 10 4 meters squared per second such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry

a hypothesis for delayed dynamic earthquake triggering 1 it s uncertain whether more near field earthquakes are triggered by static or dynamic stress changes this ratio matters because static earthquake interactions are increasingly incorporated into probabilistic forecasts recent studies were unable to demonstrate all predictions from the static stress change hypothesis particularly seismicity rate reductions however current dynamic stress change hypotheses do not explain delayed earthquake triggering and omori s law here i show numerically that if seismic waves can alter some frictional contacts in neighboring fault zones then dynamic triggering might cause delayed triggering and an omori law response the hypothesis depends on faults following a rate state friction law and on seismic waves changing the mean critical slip distance dc at nucleation zones

austral summer n2o sink and source characteristics and their impact factors in prydz bay antarctica the ocean particularly the southern ocean is considered a significant source of atmospheric n2o which is an ozone depleting greenhouse gas however there are limited data available supporting this conclusion thus this study sampled and analyzed the oceanic n2o in prydz bay the results demonstrated that the distribution of n2o in this embayment differed between the north and south sides of the antarctic slope front asf corresponding to the different hydrographic characteristics on each side although the air to sea n2o flux north of the shelf break is 1 20 0 44 mol m 2 d 1 the source sink characteristics need to be further constrained because the circumpolar deep water cdw may occasionally outcrop over the surface layer the water masses over the continental shelf south of the shelf break may be a temporary or even a permanent n2o sink when sea ice is absent the air to sea flux south of the shelf break is 3 65 0 95 mol m 2 d 1 and the water column is undersaturated with n2o which may result from the deep convection of n2o undersaturated surface water during the winter evidence also suggests that the formation of antarctic bottom water aabw may provide a pathway for n2o removal from the upper layer at high latitudes

eleven month high resolution pollen and spore sedimentation record off sw java in the indian ocean abstract settling particles collected in a sediment trap 60 km off sw java in the indian ocean at a 2200 m deep site about 830 m above the sea floor between december 2001 and november 2002 intervals of 16 days for 11 months were analyzed for the abundance and taxa composition of pollen and spores several factors control their deposition such as the monsoon driven reversal of the wind directions and ocean currents as well as flowering periods long distance transport plays a particular role during the monsoon seasons during the nw monsoon mid december beginning of march maxima of picea type alnus pinus and quercus pollen occur in the trap samples which correspond to wind and marine currents coming from the north probably the equatorial counter current and southern java current transporting pollen from the southern part of continental asia and sumatra to the research area during the se monsoon end of july mid november an increase of pollen originating from southeast indonesia and australia was observed pollen grains were probably transported by the south equatorial current and partly by the leeuwin current casuarina and in part eucalyptus are most abundant during this period during the intermonsoon period assemblages are mainly composed of pollen originating from west java maxima of some pollen taxa such as elaeocarpus myrica dacrycarpus type casuarina eucalyptus and podocarpus type probably reflect their flowering periods the transportation time from the pollen source area to the sediment trap is about 1 2 months the extrapolated pollen accumulation rate of the marine sediment trap would be about 1670 grains cm 2 yr the trap collected low concentrations of mangrove pollen which might be the result of the strong destruction of the mangrove belt in java during recent decades high values of poaceae pollen are probably related to the land use forest canopy opening and development of the secondary vegetation in west java the majority of the pollen and spores collected by the sediment trap reflects the vegetation of sw java but long distance transport in particular by the marine currents during the se and ne monsoons needs to be considered when interpreting marine pollen records off sw java in the eastern indian ocean

limited dynamic earthquake triggering in the socorro magma body region rio grande rift new mexico abstract dynamic earthquake triggering the process through which stresses transmitted through the passage of seismic waves can trigger remote faults to fail has been shown to be fairly common throughout the globe and especially in seismically active areas of high heat flow and geothermal activity we explore the possibility of dynamic earthquake triggering around the socorro magma body a feature within the rio grande rift in new mexico that exhibits high heat flow and heightened seismicity because the area fits the environment type in which triggering preferentially occurs we examine 319 global mainshocks with m w 6 0 for the possibility of increased seismicity rates following the passage of the mainshock waves we examine local event locations and origin times relative to mainshock phase arrivals for patterns distinguishing triggering mainshocks from nontriggering mainshocks we find a small triggering response during the time period analyzed unlike following the 2002 denali fault earthquake dfe this small response corresponds to smaller peak dynamic stresses than are found in other triggering studies m w 7 0 at a regional to small teleseismic distance

nitrogen biogeochemical cycling in the northwestern indian ocean abstract the vertical distribution and fine scale structure of nitrate no 3 nitrite no 2 nitrous oxide n 2 o phosphate po 4 oxygen o 2 and chlorophyll chl were determined in the north western indian ocean nwio along a meridional section 67 e from the equator to the gulf of oman using an autoanalyser for micromolar levels of nutrients and chemiluminescence and gas chromatographic methods for nanomolar levels of no 3 and no 2 and n 2 o respectively three biogeochimically contrasting regimes were investigated 1 the highly oligotrophic nutrient depleted subtropical gyre 2 the nonsoonal upwelling of nutrient rich intermediate waters of the southeastern arabian coast and 3 the denitrifying o 2 depleted zone odz ca 150 1200 m depth in the arabian sea concentrations of no 3 and no 2 were severely depleted in surface oligotrophic waters from the equator average 43 and 3 6 nm respectively to the subtropical gyre 12 15 n average 13 3 and 2 0 nm respectively with similar levels in the more stratified gulf of oman upwelling waters off southern arabia had three orders of magnitude higher no 3 levels and throughout the nwio the calculated no 3 fuelled primary production appeared to be regulated by no 3 concentration existing redfield o 2 no 3 regeneration ratios 9 1 previously derived for the deep indian ocean were confirmed 9 35 within the oxic upper layers of the nwio the no potential temperature relationship broecker 1974 earth and planetary science letters 23 100 107 needed for the derivation of expected no 3 and no 3 deficits within the denitrifying odz were refined using an isopycnal binary mixing model along the 26 6 density layer to take into account the inflowing contribution of no 3 depleted persian gulf water vertically integrated no 3 deficits increased northwards from 0 8 mol no 3 n m 2 at sta 2 04 n up to 6 49 mol no 3 n m 2 at sta 9 at the mouth of the gulf of oman then decreased to 4 10 moles no 3 n m 2 toward sta 11 near the straits of hormuz when averaged for the denitrification area of the arabian sea this corresponds to a deficit of 118 tg no 3 n adopting a recent freon 11 based estimate of water residence time of 10 years olson et al 1993 deep sea research ii 40 673 685 for the o 2 depleted layer we calculate an annual net denitrification flux of 11 9 tg n to the atmosphere or approximately 10 of the global water column denitrification rates supersaturated n 2 o concentrations were found in both surface oxic and upwelling waters up to 246 and peaked at the base of the odz up to 1264 in the northern arabian sea both nitrification in oxic waters and denitrification in hypoxic layers can be invoked as sources of n 2 o the inventory of excess n 2 o amounted to 2 55 1 3 tg n 2 o n corresponding to annual production of 0 26 0 13 tg from denitrification this is comparable to earlier law and owens 1990 nature 346 826 828 estimates of the ventilation flux of n 2 o 0 22 0 39 tg yr 1 from the upwelling region of the arabian sea the decadal response times for circulation deoxygenation denitrification and ventilation of the odz derived n 2 o and co 2 greenhouse gases and their monsoonal coupling implies the arabian sea is a sensitive oceanic recorder of global climate change

stress triggering in thrust and subduction earthquakes and stress interaction between the southern san andreas and nearby thrust and strike slip faults 1 we argue that key features of thrust earthquake triggering inhibition and clustering can be explained by coulomb stress changes which we illustrate by a suite of representative models and by detailed examples whereas slip on surface cutting thrust faults drops the stress in most of the adjacent crust slip on blind thrust faults increases the stress on some nearby zones particularly above the source fault blind thrusts can thus trigger slip on secondary faults at shallow depth and typically produce broadly distributed aftershocks short thrust ruptures are particularly efficient at triggering earthquakes of similar size on adjacent thrust faults we calculate that during a progressive thrust sequence in central california the 1983 mw 6 7 coalinga earthquake brought the subsequent 1983 mw 6 0 nunez and 1985 mw 6 0 kettleman hills ruptures 10 bars and 1 bar closer to coulomb failure the idealized stress change calculations also reconcile the distribution of seismicity accompanying large subduction events in agreement with findings of prior investigations subduction zone ruptures are calculated to promote normal faulting events in the outer rise and to promote thrust faulting events on the periphery of the seismic rupture and its downdip extension these features are evident in aftershocks of the 1957 mw 9 1 aleutian and other large subduction earthquakes we further examine stress changes on the rupture surface imparted by the 1960 mw 9 5 and 1995 mw 8 1 chile earthquakes for which detailed slip models are available calculated coulomb stress increases of 2 20 bars correspond closely to sites of aftershocks and postseismic slip whereas aftershocks are absent where the stress drops by more than 10 bars we also argue that slip on major strike slip systems modulates the stress acting on nearby thrust and strike slip faults we calculate that the 1857 mw 7 9 fort tejon earthquake on the san andreas fault and subsequent interseismic slip brought the coalinga fault 1 bar closer to failure but inhibited failure elsewhere on the coast ranges thrust faults the 1857 earthquake also promoted failure on the white wolf reverse fault by 8 bars which ruptured in the 1952 mw 7 3 kern county shock but inhibited slip on the left lateral garlock fault which has not ruptured since 1857 we thus contend that stress transfer exerts a control on the seismicity of thrust faults across a broad spectrum of spatial and temporal scales

deep structure of the northern rio grande rift beneath the san luis basin colorado from a seismic reflection survey implications for rift evolution abstract a seismic reflection survey by chevron across the san luis basin northern rio grande rift and san juan volcanic field of southern colorado is reprocessed with extended correlation to search for basement structure the trace of the main bounding fault of the basin a high angle normal fault against the sangre de cristo range can be correlated to a wide zone of dipping reflection fabric and soles out at lower crustal depths 26 28 km the deeper reflection fabric represent either broad extensional strain or pre existing structure such as a laramide thrust system the sangre de cristo bounding fault in san luis basin does not sole out at mid crustal depths but continues into the lower crust with a shallower dip the basin architecture in the northern rio grande rift san luis basin provides little if any evidence that the sangre de cristo bounding fault should flatten in a shallow listric fashion this fault geometry is quite similar to the high angle bounding fault in the espanola basin but contrasts with less deeply rooted faults in the albuquerque basin in the central rio grande rift deeper soling out of the sangre de cristo bounding fault could be due to less extension in the northern rio grande rift and or greater strength of the lithosphere compared to the central rio grande rift unequivocal moho reflections beneath the san luis basin cannot be identified probably due to limited signal penetration or a gradational nature of the moho the majority of rift related movement observed on the sangre de cristo bounding fault is post eocene either the western margin of the basin is marked by a tight monocline or a low angle normal fault

a vertical gradient of nitrous oxide below the subsurface of the canada basin and its formation mechanisms the ocean is regarded as a significant source of n2o which is an ozone depleting greenhouse gas however the contribution of the arctic ocean to the global n2o budget is not yet known herein the first observations of n2o concentrations in the canada basin cb and greenland sea basin gsb are presented a correlation between the historic atmospheric n2o record and n2o concentrations at the corresponding depth in the gsb suggests that the n2o distribution pattern is dominated by air sea exchanges and hydrographic processes in this region the consistency between the observed n2o concentrations in the cb and calculated results based on the above correlation suggest that the n2o concentrations in the cb are most likely dominated by n2o dynamics and subsequent hydrographic processes in the sea adjacent to the gsb the n2o concentration in the canada basin intermediate water cbiw reflects anthropogenic influences whereas the n2o concentration in the canada basin deep water cbdw suggests that the cbdw may be a preindustrial relict

contributions of denitrification and mixing on the distribution of nitrous oxide in the north pacific 1 we analyzed n2o isotopomer ratios distribution of isotopes within n2o molecules in the eastern tropical north pacific the n2o isotopomer ratios indicate the contribution of denitrification in the oxygen minimum zone omz 600 m in depth in the western north pacific which is not consistent with the widely accepted nitrification hypothesis our models indicate that the n2o yield per mole o2 consumed dn2o do2 is 0 008 0 0 015 nmol mol during remineralization and nitrification in the western north pacific nitrification in aerobic deep waters is a minor source of oceanic n2o whereas the n2o production in the omz is the dominant factor for the oceanic n2o distribution the denitrification in the omz is consistent with the correlation between n2o level above atmospheric equilibrium and aou apparent oxygen utilization and the parallel 18o enrichment of n2o and o2 in the omz which have been believed to support the nitrification hypothesis

mechanics of active magmatic intraplating in the rio grande rift near socorro new mexico 1 we investigate long term deformation due to the socorro magma body smb one of the largest active intrusions in the earth s continental crust using interferometric synthetic aperture radar insar observations and finite element simulations insar data spanning 15 years 1992 2007 indicate that the magma body is associated with a steady crustal uplift at a rate of about 2 mm yr 1 previous work showed that while the pattern of surface uplift is consistent with an elastic inflation of a large sill like magma body the smb could not have formed via steady elastic inflation because the latter would be outpaced by magma solidification we resolve this problem using coupled thermo visco elastic models and place constraints on the intrusion history as well as the rheology of the ambient crustal rocks we demonstrate that observations rule out the linear maxwell response of the ductile crust but are consistent with laboratory derived power law rheologies our preferred model suggests that the age of the smb is of the order of 103 years and that the apparent constancy of the present day uplift may be due to slow heat transfer and ductile deformation in a metamorphic aureole of a giant sill like magma intrusion rather than due to a steady increase in the magma overpressure the smb is a contemporaneous example of magmatic intraplating a process by which large volumes of mafic melt stall and spread at midcrustal depths due to density or rheology contrasts

dynamic stresses coulomb failure and remote triggering dynamic stresses associated with crustal surface waves with 15 30 sec periods and peak amplitudes 5 km the latter is consistent with the observation that extensional or transtensional tectonic regimes are more susceptible to remote triggering by rayleigh wave dynamic stresses than compressional or transpressional regimes locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal volcanic systems

the rain forest in java through the quaternary and its relationships with humans adaptation exploitation and impact on the forest abstract relations between humans and the rain forest in java island began during the lower pleistocene but clear evidence for anthropic impact and clearance of the forest does not occur until late in the holocene after the rise of the ancient kingdoms on java at the end of 1st millennium a d the history of landscape change in java over the last 2 5 million years appears highly complex and linked to the repetitive expansion and fragmentation of the rain forest over this time these processes are now much better understood thanks to the range of palaeoenvironmental studies undertaken at various altitudes and in locations that show the dynamics of rain forest in response to variations in climatic and regional environmental change the extent of rain forest throughout the holocene appears to have been quite sensitive to small perturbations making it somewhat difficult to discriminate especially for relatively ancient holocene forest recessions between a climatic cause and one of anthropic origin clear evidence of intensive human impact on rain forest is observed late c 1500 years ago a pattern that is repeated in other parts of island southeast asia this paper will focus on the history of the landscape changes in java during the quaternary with special reference to the dynamics of rain forest structure and composition largely drawn from available pollen analyses subsequently the paleoenvironmental palaeoanthropological and archaeological records are considered to investigate the adaptive relationships between human groups and the forest through time

distributed deformation across the rio grande rift great plains and colorado plateau we use continuous measurements of gps sites from across the rio grande rift great plains and colorado plateau to estimate present day surface velocities and strain rates velocity gradients from five east west profiles suggest an average of 1 2 nanostrains yr east west extensional strain rate across these three physiographic provinces the extensional deformation is not concentrated in a narrow zone centered on the rio grande rift but rather is distributed broadly from the western edge of the colorado plateau well into the western great plains this unexpected pattern of broadly distributed deformation at the surface has important implications for our understanding of how low strain rate deformation within continental interiors is accommodated

preliminary estimates for the radiocarbon age of deep water in the glacial ocean radiocarbon ages for benthic and planktonic foraminifera from the late glacial sections of two atlantic and two pacific cores are reported the differences for benthic planktonic pairs suggest that the radiocarbon age for deep atlantic water was somewhat larger than today s i e 600 250 as opposed to 400 years and that the radiocarbon age for deep pacific water was also slightly larger than today s 2100 400 as opposed to 1600 years our results suggest that during glacial time the deep pacific was as it is today significantly depleted in radiocarbon relative to the deep atlantic as many questions remain unanswered regarding the reliability of this approach these conclusions must be considered to be preliminary

remote triggered seismicity caused by the 2011 m9 0 tohoku oki japan earthquake 1 seismic waves from large earthquakes have been shown to trigger seismicity large distances from a mainshock and this is termed remotely or dynamically triggered seismicity we performed a global search for seismicity potentially triggered by the seismic waves from the 2011 m9 0 tohoku oki japan earthquake using seismograms from global seismic networks and an event catalog we search for earthquakes and tremors instantaneously triggered during the passing of the seismic waves as well as for statistically significant changes in local and global seismic rates after the passing of the waves for earthquakes we find potential cases of instantaneous triggering in the united states russia china ecuador and mexico while for tremors we find evidence for triggering in taiwan armenia cuba and the united states in addition we observed a potential case of delayed triggering of larger magnitude earthquakes including a m5 2 in baja california mexico

how much deep water is formed in the southern ocean three tracers are used to place constraints on the production rate of ventilated deep water in the southern ocean the distribution of the water mass tracer po4 phosphate star in the deep sea suggests that the amount of ventilated deep water produced in the southern ocean is equal to or greater than the outflow of north atlantic deep water from the atlantic radiocarbon distributions yield an export flux of water from the north atlantic which has averaged about 15 sv over the last several hundred years cfc inventories are used as a direct indicator of the current production rate of ventilated deep water in the southern ocean although coverage is as yet sparse it appears that the cfc inventory is not inconsistent with the deep water production rate required by the distributions of po4 and radiocarbon it has been widely accepted that the major part of the deep water production in the southern ocean takes place in the weddell sea however our estimate of the southern ocean ventilated deep water flux is in conflict with previous estimates of the flux of ventilated deep water from the weddell sea which lie in the range 1 5 sv possible reasons for this difference are discussed

global omori law decay of triggered earthquakes large aftershocks outside the classical aftershock zone 1 triggered earthquakes can be large damaging and lethal as evidenced by the1999 shocks in turkey and the 2001 earthquakes in el salvador in this study earthquakes with ms 7 0 from the harvard centroid moment tensor cmt catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected about 61 of earthquakes that occurred near defined as having shear stress change 0 01 mpa the ms 7 0 shocks are associated with calculated shear stress increases while 39 are associated with shear stress decreases if earthquakes associated with calculated shear stress increases are interpreted as triggered then such events make up at least 8 of the cmt catalog globally these triggered earthquakes obey an omori law rate decay that lasts between 7 11 years after the main shock earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main shock centroid omori s law is one of the few time predictable patterns evident in the global occurrence of earthquakes if large triggered earthquakes habitually obey omori s law then their hazard can be more readily assessed the characteristic rate change with time and spatial distribution can be used to rapidly assess the likelihood of triggered earthquakes following events of ms 7 0 i show an example application to the m 7 7 13 january 2001 el salvador earthquake where use of global statistics appears to provide a better rapid hazard estimate than coulomb stress change calculations

multi proxy evidence for human induced deforestation and cultivation from a late holocene stalagmite from middle java indonesia abstract speleothem multi proxy records have proved highly useful in reconstructing past changes in climatic and environmental conditions as well as karst processes and in distinguishing between the numerous potential driving forces that influence these proxies there is lack of such terrestrial proxies from the tropical indo pacific for the first time we present an annual to decadal scale multi proxy record of 377 samples including stable isotopes 18o 13c and trace elements mg ca sr ca from a holocene calcite stalagmite from bribin cave gunung kidul regency middle java indonesia that has grown over the last 4000 years 11 230th dates 18o values average 7 with high frequency variability of up to 1 and hint at relatively stable overall climatic conditions in the tropical indo pacific region during the late holocene the 13c values of stalagmite jb2 are low 13 at the beginning of the record suggesting a c3 dominated rainforest cover strong positive covariation with mg ca and sr ca ratios is a stringent indication of a dominant natural control by prior calcite precipitation and water rock interaction however 13c values increase dramatically by 4 from 1 1 ka to 0 5 ka clear evidence of an anthropogenic influence through deforestation and cultivation