We have compiled 223 sedimentary charcoal records from Australasia in order to examine the temporal and spatial variability of fire regimes during the Late Quaternary. While some of these records cover more than a full glacial cycle, here we focus on the last 70,000 years when the number of individual records in the compilation allows more robust conclusions. On orbital time scales, fire in Australasia predominantly reflects climate, with colder periods characterized by less and warmer intervals by more biomass burning. The composite record for the region also shows considerable millennial-scale variability during the last glacial interval (73.5e14.7 ka). Within the limits of the dating uncertainties of individual records, the variability shown by the composite charcoal record is more similar to the form, number and timing of DansgaardeOeschger cycles as observed in Greenland ice cores than to the variability expressed in the Antarctic ice-core record. The composite charcoal record suggests increased biomass burning in the Australasian region during Greenland Interstadials and reduced burning during Greenland Stadials. Millennial-scale variability is characteristic of the composite record of the subtropical high pressure belt during the past 21 ka, but the tropics show a somewhat simpler pattern of variability with major peaks in biomass burning around 15 ka and 8 ka. There is no distinct change in fire regime corresponding to the arrival of humans in Australia at 50 AE 10 ka and no correlation between archaeological evidence of increased human activity during the past 40 ka and the history of biomass burning. However, changes in biomass burning in the last 200 years may have been exacerbated or influenced by humans.

Nine separate Cambrian to Carboniferous terranes are recognized in West Junggar, northwest China. They were amalgamated as part of the Central Asian Orogenic Belt which records accretion of continental, island-arc and oceanic terranes to Archaean-Proterozoic continental nuclei. Tangbale, Kekesayi, Ebinur and Mayila terranes (Cambrian-Silurian) evolved in intra-oceanic settings and docked, along a series of north-dipping subduction zones, on to the Laba terrane to their south. This southern continent was contiguous with lithosphere of the Kulumudi Ocean to the north. Devonian subduction on the northern edge of this ocean resulted in formation of a continental arc (Toli terrane) and accretionary complex (Kulumudi terrane). The Karamay terrane formed as an accretionary complex during the Carboniferous. The ophiolitic Sartuohai terrane was emplaced as m~lange between Kulumudi and Karamay terranes during the Late Carboniferous. Subduction migrated southward, continuing beneath these terranes, resulting in the intrusion of I-type granites into the Toli, Kulumudi, Sartuohai and Karamay terranes. These granites are closely associated with epithermal and porphyry-style gold mineralization. Composite terranes either side of the Kulumudi Ocean collided in the Late Carboniferous, marking the final consolidation of Central Asia. Collision was accompanied by anorogenic granite and diabase dyke intrusion, followed by widespread latest Carboniferous to Permian extension, and subsequently the formation of the Junggar Basin. West Junggar has been further disrupted by Cenozoic strike-slip faulting along Junggar and Dalabute faults.

The Lajishan ophiolite complex in the Qilian Orogen is one of several ophiolites situated between the Qaidam and North China blocks that record episodic closure of the Proto-Tethyan Ocean. Detailed field relations and geochemical and geochronological studies are critical to unraveling the tectonic processes responsible for an extensive period of intraoceanic subduction that produced juvenile ophiolite/island arc terranes, which were obducted onto continental margins during ocean closure. The Lajishankou ophiolite complex crops out along the northern margin of the South Qilian belt and was thrust over a Neoproterozoic-Ordovician passive margin sequence that was deposited upon the Proterozoic Central Qilian block. The mafic rocks in Lajishankou ophiolite complex are the most abundant slices and can be categorized into three distinct groups based on petrological, geochemical, and geochronological characteristics: massive island arc tholeiites, 509-Ma back-arc dolerite dykes, and 491-Ma pillow basaltic and dolerite slices that are of seamount origin in a back-arc basin. These results, together with spatial relationships, indicate that the Cambrian island arc rocks, ophiolite complex, and accretionary complex developed between 530 and 480 Ma as a single, intraoceanic arc-basin system as a result of south directed subduction of the Proto-Tethyan Ocean prior to Early Ordovician obduction of this system onto the Central Qilian block. Final continental amalgamation involved continental collision of the Central Qilian block with the Qaidam block during the Late Ordovician. This model solves the long-lasting discussion on the emplacement of the Lajishan ophiolite and contributes to an improved understanding of multiple accretionary and collisional processes in the Qilian Orogen.

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(2013). The tectonic evolution of a Neo-Tethyan (Eocene-Oligocene) island-arc (Walash and Naopurdan groups) in the Kurdistan region of the Northeast Iraqi Zagros Suture Zone. Island Arc, 22 (1), 104-125.The tectonic evolution of a Neo-Tethyan (Eocene-Oligocene) island-arc (Walash and Naopurdan groups) in the Kurdistan region of the Northeast Iraqi Zagros Suture Zone AbstractThe Walash and Naopurdan groups are incorporated into the lower allochthonous thrust sheet in the Iraqi Zagros Suture Zone (IZSZ). 40Ar-39Ar dates on magmatic feldspar separates from both Walash and Naopurdan volcanic rocks indicate an Eocene-Oligocene age (43.01 ± 0.15 to 24.31 ± 0.60 Ma). The Walash and Naopurdan groups form a thrust sheet that is structurally overlain by an upper allochthon of Cretaceous arc-related rocks (106-92 Ma) now known as the Hasanbag igneous complex (formerly known as the Gemo-Qandil Group). The Walash and Naopurdan lower allochthon is thrust over the foreland basin Red Beds series. Volcanic and subvolcanic units in the Walash and Naopurdan groups were studied from the Mawat, Galalah-Choman, Leren, and Qalander-Sheikhan provinces. Most of these rocks are basaltic to andesitic for both the Naopurdan and Walash suites. The petrographic study shows that these rocks are affected by metamorphic alteration under greenschist facies conditions, but preserve primary porphyritic textures with some relict igneous plagioclase, pyroxene, and hornblende. The enrichments in LREE/HREE and high Th/Nb and Nb/Zr show that the Walash and Naopurdan rocks have distinct subduction-related signatures: specifically island-arc tholeiite for the Naopurdan and calc-alkaline to alkaline for the Walash suites. Hence the Walash and Naopurdan suites are back-arc and arc systems, respectively, that developed 43-24 Ma. Accordingly, the IZSZ contains a full record of Neo-Tethys pre-collision-related volcanism in dual subduction settings, from the Early Cretaceous (Hasanbag igneous complex) to the Eocene-Oligocene (Walash-Naopurdan suites). Final continent-continent collision started when the last of the Neo-Tethys Ocean was subducted beneath the Iranian continent, resulting in its collision with the Arabian Plate, probably during the Middle Miocene. This reinforces a continuity of events along the entire edge of the Arabian Plate from Turkey, through Iraq and Iran, and into Oman.