Las “rocas balanceadas”, esas atractivas y curiosas geoformas

Para las personas sin formación en Geología y Geomorfología, las “rocas balanceadas” se encuentran entre las geoformas más espectaculares y curiosas del paisaje. Muchas de ellas atraen turistas por lo que tienen un alto valor comercial, así como estético, escénico y cultural, por lo cual están directamente vinculadas al Patrimonio Geológico y al Geoturismo, y consecuentemente, al vandalismo.Fundación Museo de La Plat

The Permian Geology, Physiography and Landscape Evolution of Northeastern Victoria

Northeast Victorian diamictites (tillites) and interstratified traction deposits (fluvioglacials), now mapped in detail and interpreted as glacial, contain: uni- and multidirectionally striated clasts; striated clasts with environmentally diagnostic shapes (wedges and bullets); and occasionally striated fossiliferous (Siluro-Devonian faunal assemblages) and non-fossiliferous erratics. The sequences represent proximal sedimentation associated with a wasting ice-front, south of the Wangaratta area. Associated with these sediments are seven pavement surfaces, recognised as glacial (one - a miniature roche moutonnee) and indicating ice-movement from south to north. Petrographic data show derivation of non-fossiliferous erratics from local and distant source terrains south of the study area. Palaeontological data show derivation of the exotic fossiliferous erratics from beyond the present southern margin of the Australian craton. Local preservation and general distribution of glacial deposits reflects original Permian topography rather than subsequent graben tectonics. There is no geological evidence for an Ovens Graben. The present landscape reflects tilt-block tectonics similar in structural pattern to that developed across the north of the state, and is in part at least a preserved Permian feature. The radiometric age of basalt in Glenrowan Gap (on the western side of the Ovens tilt-block) demonstrates the Gap's existence before 36 Ma. Glacials suggest a relict Permian ice-spill path to the NW

The hoax of ocean acidification

A widespread alarm is sweeping the world at present about the ill effects of man-made increases in carbon dioxide (CO2) production. One aspect is that it may cause the ocean to become acid, and dissolve the carbonate skeletons of many living things including shellfish and corals. However, the oceans are not acid, never have been in geological history, and cannot become acid in the future. Changes in atmospheric CO2 cannot produce an acid ocean. Marine life depends on CO2, and some plants and animals fix it as limestone. Over geological time enormous amounts of CO2 have been sequestered by living things, and today there is far more CO2 in limestones than in the atmosphere or ocean. Carbon dioxide in seawater does not dissolve coral reefs, but is essential to their survival

Problems of geotourism and geodiversity

Early definitions of geotourism stressed tourism related to geology and geomorphology, though some drifted into other concepts such as education, sustainability, conservation and more. Later definitions, largely fostered by National Geographic, treat the topic as related to geography, or more simply place, and concentrate on the extraneous topics such as sustainability, conservation and so forth which should be part of any form of tourism. The earth science community is liable to lose its influence on creation and interpretation of geosites and related topics because the concept has been broadened to include everything. Geodiversity is a copy-cat adaptation of biodiversity, but while biodiversity might be a measure of the health of an ecosystem, the value of geological and geomorphic sites does not depend on diversity. Many geological and geomorphic features are restricted to a single rock or feature, which enhances their value. Geodiversity might be useful as a way of recording diverse features within a given area, but it should not be treated as a value-judgement on the significance of individual sites. The whole area of geoheritage is under threat from the redefinition of geotourism, and the mis-application of the concept of geodiversity

PACIFIC SEA LEVELS RISING VERY SLOWLY AND NOT ACCELERATING

Over the past decades, detailed surveys of the Pacific Ocean atoll islands show no sign of drowning because of accelerated sea-level rise. Data reveal that no atoll lost land area, 88.6% of islands were either stable or increased in area, and only 11.4% of islands contracted. The Pacific Atolls are not being inundated because the sea level is rising much less than was thought. The average relative rate of rise and acceleration of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, are both negative, −0.02139 mm yr−1 and −0.00007 mm yr−2 respectively. Since the start of the 1900s, the sea levels of the Pacific Ocean have been remarkably stable

Pacific Sea Levels Rising Very Slowly and Not Accelerating

Over the past decades, detailed surveys of the Pacific Ocean atoll islands show no sign of drowning because of accelerated sea-level rise. Data reveal that no atoll lost land area, 88.6% of islands were either stable or increased in area, and only 11.4% of islands contracted. The Pacific Atolls are not being inundated because the sea level is rising much less than was thought. The average relative rate of rise and acceleration of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, are both negative, −0.02139 mm yr−1 and −0.00007 mm yr−2 respectively. Since the start of the 1900s, the sea levels of the Pacific Ocean have been remarkably stable

Atlantic meridional overturning circulation stable over the last 150 years

The Atlantic Meridional Overturning Circulation (AMOC) describes the northward flow of warm, salty water in the upper layers, and the southward flow of colder water in the deep Atlantic layers. AMOC strength estimates at 41°N latitude based on satellite sea surface height (SSH), and ARGO ocean temperature, salinity and velocity, and finally the difference in between the absolute mean sea levels (MSL) of the tide gauges of The Battery, New York, 40.7°N latitude, and Brest, 48.3°N latitude. Results suggest that the AMOC has been minimally reducing but with a positive acceleration since 2002, has been marginally increasing but with a negative acceleration since 1993, and has not been reducing but only oscillating with clear periodicities up 18 years, 27 years and about 60 years since 1856

Atlantic meridional overturning circulation stable over the last 150 years

The Atlantic Meridional Overturning Circulation (AMOC) describes the northward flow of warm, salty water in the upper layers, and the southward flow of colder water in the deep Atlantic layers. AMOC strength estimates at 41°N latitude based on satellite sea surface height (SSH), and ARGO ocean temperature, salinity and velocity, and finally the difference in between the absolute mean sea levels (MSL) of the tide gauges of The Battery, New York, 40.7°N latitude, and Brest, 48.3°N latitude. Results suggest that the AMOC has been minimally reducing but with a positive acceleration since 2002, has been marginally increasing but with a negative acceleration since 1993, and has not been reducing but only oscillating with clear periodicities up 18 years, 27 years and about 60 years since 1856

The Atlantic Meridional Overturning Circulation is not collapsing

Boers (2021) wrote that, in the last century, the Atlantic Meridional Overturning Circulation (AMOC) may have evolved from relatively stable conditions to a point close to a critical transition. The claim is based on different AMOC indices, based on observational sea-surface temperature and salinity data from across the Atlantic Ocean basin. Boers’ conclusions (2021) are not based on systematic observations spanning the last and this century, but on subjective reconstructions of sea surface temperature and salinity, as accurate sea-surface and temperature data are only available over the last few decades. Additionally, the AMOC strength does not only correlate to sea surface temperature and salinity data. His as-sumption that the strength of the AMOC depends on poorly described sea-surface temperature and salinity only is not substantiated. The difficulties of estimating the sea surface temperature (SST) are highlighted in Chan et al. (2019). Even more difficult are the estimations of salinity