Supplemental Material: Evaluating preservation bias in the continental growth record against the monazite archive

Table S1 (global compilation of monazite ages); Table S2 (compilation of whole rock geochemistry of monazite-bearing rocks); data sources for the zircon ages from the Himalayan orogen and Figure S1 (comparison of monazite and zircon age histograms and cross-correlation results based on the monazite dating method).<br>

Supplemental Material: Evaluating preservation bias in the continental growth record against the monazite archive

Table S1 (global compilation of monazite ages); Table S2 (compilation of whole rock geochemistry of monazite-bearing rocks); data sources for the zircon ages from the Himalayan orogen and Figure S1 (comparison of monazite and zircon age histograms and cross-correlation results based on the monazite dating method).<br>

Paleoseismological Findings at a New Trench Indicate the 1714 M8.1 Earthquake Ruptured the Main Frontal Thrust Over all the Bhutan Himalaya

The 1714 Bhutan earthquake was one of the largest in the Himalaya in the last millennium. We show that the surface rupture caused by this earthquake extended further to the east than previously known, it was at least 175 km long, with slip exceeding 11 m at our study site. The age of the surface rupture was constrained by a combination of radiocarbon and traditional optically stimulated luminescence dating of affected river sediments. Computations using empirical scaling relationships, fitting historical observations and paleoseismic data, yielded a plausible magnitude of Mw 8.1 ± 0.4 and placed the hypocentre of the 1714 Bhutan earthquake on the flat segment of the Main Himalayan Thrust (MHT), the basal décollement of the Himalayan orogen. Calculations of Coulomb stress transfer indicate that great earthquakes along the leading part of the MHT would cause surface rupture. In contrast, distal earthquakes may not immediately trigger surface rupture, although they would increase the stresses in the leading part of the MHT, facilitating future surface-rupturing earthquakes. Frontal earthquakes would also transfer stress into the modern foreland basin facilitating southward propagation of the MHT as a blind basal décollement. In conclusion, studies of surface-rupturing events alone likely underestimate the seismic slip along the Himalayan megathrust.

Construction of the Lesser Himalayan–Subhimalayan thrust belt: The primary driver of thickening, exhumation, and high elevations in the Himalayan orogen since the middle Miocene

Documenting the structural evolution of the Himalayan orogen is fundamental for understanding the dynamics of collisional orogenesis. We argue that the importance of deformation in the frontal, Lesser Himalayan–Subhimalayan (LH-SH) portion of the Himalayan thrust belt for driving crustal thickening over the past ~15–13 m.y. has long been overlooked. To quantify its contribution to thickening, we measured parameters from 22 published cross sections that span the length of the orogen. The mean structural uplift accomplished by the LH-SH thrust belt increases from 10–15 km in the eastern half of the orogen to 15–23 km in the western half. An antiformal culmination constructed by LH duplexing is observed across the orogen and increases in structural height (to as much as 15–20 km) and north-south width moving westward. Construction of the culmination was the primary mechanism for building and maintaining wedge taper. The westward scaling of culmination size is accompanied by doubling and tripling of LH-SH shortening and accretion magnitude, respectively; when combined with a consistent orogen-wide modern taper angle (11° ± 2°), this indicates that duplexing facilitated the growth of an overall larger orogenic wedge moving westward. Following the initial southward propagation of deformation into LH rocks at ca. 15–13 Ma, the Himalayan orogenic wedge has been characterized by stacking of multiple thin, smalldisplacement thrust sheets to develop a high-taper orogenic wedge. Thus, LH-SH deformation has had a profound effect on driving thickening, exhumation, and the attainment of high elevations since the middle Miocene.

Supplemental Material: Construction of the Lesser Himalayan–Subhimalayan thrust belt: The primary driver of thickening, exhumation, and high elevations in the Himalayan orogen since the middle Miocene

Supplemental figures and tables that provide supporting data for the compiled cross sections and the measured parameters, as well as text that summarizes the tectonostratigraphic units on each cross section.<br>

Supplemental Material: Construction of the Lesser Himalayan–Subhimalayan thrust belt: The primary driver of thickening, exhumation, and high elevations in the Himalayan orogen since the middle Miocene

Supplemental figures and tables that provide supporting data for the compiled cross sections and the measured parameters, as well as text that summarizes the tectonostratigraphic units on each cross section.<br>