Barrell was well prepared for a fruitful and scholarly career in the earth sciences: he studied engineering at Lehigh University, graduating with high honors in 1892, and continued there for E. M. and M. S. degrees in 1893 and 1897. He received the Ph.D. in geology from Yale in 1900 and the D. Sc. from Lehigh in 1916. To defray the expense of such extended education, Barrell took part-time positions teaching mathematics, mining and metallurgy, geology, zoology, a nd astronomy; he considered this experience invaluable when he became professor of structural geology at Yale (19080–1919).
Although he was concerned with a variety of problems, from mining technology to the evolution of protoman, Barrell’s chief contributions were in isostasy, sedimentology, and metamorphism. He preferred building theories to collecting data, and his most impressive papers were deductive interpretations of the work of others. When writing on a particular topic. Barrell followed what he called the method of multiple working hypotheses: beginning with a set of carefully considered assumptions, he attempted to derive a number of hypothetical explanations that could later be checked against existing facts and theories. His own conclusions were typically prefaced with lengthy and critical presentations.
Barrell’s ideas on metamorphism grew out of fieldwork during the summers of 1897–1901. In 1901 he joined the U. S. Geological Survey in Montana, to study the Marysville mining district and large Marysville and Boulder granite batholiths. Dissatisfied with contemporary theories of their origin, he directed his efforts to an accurate description of the characteristics of igneous intrusions occurring in nature, and developed a theory of magmatic stoping. The method of invasion was by subsidence of roof blocks and the rise of magma. Superheated magma confined at great depths shows a maximum of marginal assimilation. In the zone of flowage, magmatic intrusions crowd aside their containing wall rock, with the development of peripheral schistosity, and in the zone of fracture they force strata apart, forming sheets, laccoliths, and dikes. Greatly confined magmas expand and give rise to volcanism. Charles Schuchert called the Geology of the Marysville Mining District, Montana (1907) a geological classic.
Many of Barrell’s 150 published papers deal with topics in paleoclimatology and sedimentology. He was a pioneer dry-land geologist, greatly influencing the manner in which stratigraphic problems were subsequently approached and conceptualized. Before his work, it was generally held that most sedimentary strata were of marine origin. Barrell was convinced by examination of the floodplains of western deserts and Triassic deposits of New Jersey that at least a fifth of all land surfaces are mantled by continental, fluvial, or eolian sediments.
He early recognized causal relationships between climatic variation and sedimentation, emphasizing that the ratio of terrestrial to littoral and marine deposits fluctuates markedly through time. Barrell proposed that sedimentation is a complex repetition of many compound rhythms and that such cyclic events as diastrophism, erosion, temperature change, and rainfall variation influence and are influenced by topography and physical geography, by the depth and streaming force of water bodies. He outlined numerous covarying factors of deposition in “Criteria for the Recognition of Ancient Delta Deposits” (1912) and pointed out that the heterogeneity of stratified deposits is the result.
Barrell read the history of the earth in its strata and interpreted their irregularities as meaning that geological processes are halting and discontinuous. Antiuniformitarian arguments are forcefully presented in “rhythms and the Measurements of Geologic Time” (1917), one of Barrell’s more philosophical works, Here he tried to estimate the age of the earth by calculating the rates of denudation, sedimentation, uplifts and subsidences, deposition of salt in the sea, and emission of radioactivity. The figure he obtained, 1,400 million years to the Precambrian, was more than ten times the usual uniformitarian estimates.
Geodesic theory occupied Barrell’s interest for a portion of his career. He published eight papers in the Journal of Geology (1914–1915), under the series title “Strengh of the Eath’s Crust,” that present his views on isostasy and terrestrial dynamics. Positing two crustal layers, an outermost and stronger lithosphere (50–70 miles thick and of varying density) and a zone of flowage that he named the aesthenosphere (70–300 miles thick), he sought to explain geological phenomena by their dynamic interaction. Barrell said that isostatic equilibrium obtains in general, despite the effects of erosion and sedimentation. He wrote that the lithosphere is capable of supporting limited loads, uncompensated, however, if the vertical anomaly is inversely proportional to the area. Anomalies in excess of this proportion are compensated for by vertical displacement of the lithosphere against the foundation aesthenosphere (isostatic adjustment).
Although Barrell’s concerns were seemingly diverse, they were actually variations on a common theme: the effects of physical agents on the evolution of the earth and its inhabitants. “The Origin of the Earth” (1916), a lecture delivered to Yale’s Sigma Xi Society, discussed the conditions required for the genesis of the solar system and the development of the earth. His papers on sedimentology always relate sedimentological processes to the larger problems of historical geology, as do his treatments of structural geology. Barrell even maintained that biological evolution was the result of physical and chemical agents, in that these are the factors determining the environment of organisms.
I. Original Works. Barrell’s writings include Geology of the Marysville Mining District, Montana..., U. S. Geological Survey, Professional Paper no. 57 (Washington, D. C., 1907); “Criteria for the Recognition of Ancient Delta Deposits,” in Bulletin of the Geological Society of America, 23 (1912), 377–446; the series on the strength of the earth’s crust: “Geologic Tests of the Limits of Strength,” in Journal of Geology, 22 (1914), 28–48; “Regional Distribution of Isostatic Compensation,” ibid., 145–165; “Influence of Variable Rate of Isostatic Compensation,” ibid., 209–236; “Heterogeneity and Rigidity of the Crust as Measured by Departures FromFrom Isostasy,” ibid., 289–314; “The Depth of Masses Producing Gravity Anomalies and Deflection Residuals,” ibid., 441–468, 537–555; “Relation of Isostatic Movements to Sphere of Weakness,” ibid., 655–683; “Variation of Strength With Depth,” ibid., 729–741, and 23 (1915), 27–44; and “Physical Conditions Controlling the Nature of the Lithosphere and Aesthenosphere,” ibid., 23 (1915), 425–443, 449–515; “Rhythms and the Measurements of Geologic Time,” in Bulletin of the Geological Society of America, 28 (1917), 745–904; and “The Origin of the Earth,” in Sigma Xi Society, ed., The Evolution of the Earth and Its Inhabitants (New Haven, 1918), pp. 1–44.
II. Secondary Literature. Works on Barrell are Herbert E. Gregory, “Memorial to Joseph Barrell,” in Bulletin of the Geological Society of America, 34 (1923), 18–28; G. P. Merrill, “Joseph Barrell,” in Dictionary of American Biography, I, 642–644; and Charles Schuchert, “Biographical Memoir of Joseph Barrell,” in Biographical Memoirs of the National Academy of Science, 12 (1927), 1–40.
Martha B. Kendall