Geosyncline  Geosyncline originally called a geosynclinal is an obsolete geological concept to explain orogens which was developed in the late 19th and early 20th centuries before the theory of plate tectonics was envisaged. A geosyncline was described as a giant downward fold in Earth's crust with associated upward folds (geanticlines, geanticlinals) that preceded the climax phase of orogenic deformation. The geosyncline concept was first developed by the American geologists James Hall and James Dwight Dana in the mid-19th century during the classic studies of the Appalachian Mountains. Émile Haug actualized the geosyncline concept and "reintroduced" it to Europe with a 1900 publication. Eduard Suess, a leading geologist of his time, disapproved the concept of geosyncline and argued in 1909 against its use due to its associated theories. This did not stop further developed of the concept by Leopold Kober and Hans Stille in the first half of the 20th century, both of whom worked on a contracting Earth framework. Stille and Kober had rather similar views. The development of the geosycline concept in the aftermath of Eduard Suess' book "Das Antlitz der Erde" (1883–1909) by Stille and Kober was not unchallenged as another school of thought was led by Alfred Wegener and Émile Argand. This competing view rejected Earth contraction and argued for continental drift. These two views can be called fixist in the case of geosyncline theory and mobilist for the support of continental drift. John F.Dewey and John M.Bird adapted the geosyncline concept to plate tectonics in 1970. The term continued to have usage within a plate tectonics framework in the 1980s, albeit Celâl Şengör argued in 1982 against its use considering its association to pre-plate tectonics ideas. As a geosyncline depression originated uplifted geanticlines were eroded providing sediments that filled the basin. According to Stille geosynclines formed as depressions without any faulting and if faults were found these were the product of later processes like the final collapse of the geosyncline. Collapse of geosynclines into orogens were thought by Dana and Stille to be the result of Earth's contraction over time.