Three growth in the Mesozoic and Early Tertiary and the reconstruction of palaeoclimates
Abstract Evidence from the distribution and characteristics of fossil wood in the Mesozoic and Early Tertiary indicates that a much warmer global climate prevailed in those times. There appears to have been a broad zone of largely non-seasonal climate stretching from about 32° N to 32° S (palaeolatitudes). In addition to this low-latitude zone, forest growth extended into very high palaeolatitudes where trees cannot grow at the present day. A number of theories have been proposed to account for the palaeoclimate responsible for this distribution of forests. Most notable have been those involving changes in the amount of carbon dioxide in the atmosphere, in the positions of the continents or in the obliquity of the earth's axis of rotation. Evidence from fossil forests indicates that a combination of the effects of an increased quantity of carbon dioxide in the atmosphere and the palaeopositions of the continents in the Mesozoic and Early Tertiary appears at the moment to be the simplest explanation for the climate of those geological times, without the need to invoke axial movement.