AMS dating of insect chitin – A discussion of new dates,problems and potential

Results from AMS dating applied to insect chitin from a variety of contexts and different preservation conditions and retrieval methods are presented. Secure contexts, which include other dated organic material from different geographic locations ranging from Egypt to Greenland and different chronological periods, from Lateglacial to Medieval, have been used. In addition, insect species with different dietary requirements have been selected for dating purposes in order to provide an understanding as to whether diet plays a role in the chitin dating results. Dates from each context/site are discussed separately in the context of their stratigraphy and/or archaeology. Our research concentrates on the results from pre-treatment methods which require small quantities of chitin as these could be applied in a variety of Quaternary and archaeological contexts. The dates from carbonised and desiccated remains where no chemicals had been involved in storage fell within the range of dates from other organics or the archaeology. Although some of the dates from waterlogged contexts were successful, problems were encountered and these have been linked with long term storage in various alcohols of uncertain provenance. Whilst short term immersion in paraffin (kerosene) and alcohols during processing probably has no impact, it is recommended that chitinous material for dating be stored in acidified distilled water. Our results demonstrate the potential of chitin as a dating medium and provide a basis for its wider application.     

New aposematic and presumably repellent bark cockroach from Lebanese amber

Balatronis cretacea Šmídová et Lei, 2017 – ancestor of the repellent harlequin cockroach (Insecta: Blattaria) is reported in this issue as the earliest representative of the type cockroach family Blattidae in the Cenomanian Myanmar amber (98 Ma). Balatronis libanensis sp.n. from the Lebanese amber (130 Ma) extends the palaeogeographic (to Gondwana) and chronostratigraphic (to Early Cretaceous) range of this advanced Mesozoic bark cockroach and shifts the expected origin of the Blattidae to the J/K boundary. In relation also to the living harlequin Neostylopyga rhombidifolia, B. libanensis is primitive in being extremely small, less coloured and with well-developed wings. It has the standard cockroach head and rudimentary, but clearly visible plesiomorphic macula-like central ocellus (as the only representative of the modern Mesoblattinidae–Blattidae–Ectobiidae–Blaberidae lineage) and represents the earliest significant record of an aposematic and thus very probably also a repellent and/or poisonous insect.     

New caddisflies species (Insecta: Trichoptera) from the Cretaceous Taymyr amber

Four new Trichoptera species: Kliganigadukia taymyrensis gen. et sp. nov. (Hydrobiosidae), Archaeopolycentra yantardakh sp. nov. (Polycentropodidae), Taymyrodipseudon protopegasus gen. et sp. nov. (Dipseudopsidae), and Siberoclea parapolaria gen. et sp. nov. (Leptoceridae) from Late Cretaceous amber (Santonian, Kheta Formation, 85 Ma) of Taymyr (Siberia, Russian Federation) are described and illustrated. Data on the Cretaceous amber Trichoptera (13 families, 20 genera, 29 species) are summarized and discussed.     

钦杭结合带成矿地质背景及成矿规律

钦杭成矿带是钦州湾-杭州湾成矿带的简称,具有矿床规模大、矿床分布密集、矿床类型齐全、伴生组分多样的显著特点,是中国地质调查局规划的全国重点成矿区带。钦杭成矿带又称为钦杭(构造)结合带,大地构造位置对应于扬子板块和华夏板块的接合带。研究显示,钦杭带是一条古老俯冲带。它在古生代仍存在洋壳,属于洋陆俯冲体系。中生代构造转换是一个重要的地质事件,它使钦杭带由特提斯构造域卷入到西太平洋构造域中,大地构造性质从华夏和扬子板块之间的板块构造机制为主,转为陆内岩石圈拉张伸展构造环境,并产生巨大的地质效应,最突出的是燕山期岩浆的大规模活动以及成矿作用的大爆发。燕山期花岗岩存在确切的幔源端元信息,幔源物质参与了许多矿床的形成,并为最近钨多金属矿床北拓找矿所验证。钦杭结合带是重要的斑岩铜(钼)矿带,斑岩铜(钼)矿在钦杭结合带北、中、南三段均有产出,它们的主成岩成矿年龄是燕山期,但带有古老俯冲带岛弧体系的基因。钦杭带也是一条古海洋喷流热水沉积矿床密集分布带,VMS型铜多金属矿床和SEDEX型铅锌多金属矿床发育。钦杭带是一条古老俯冲带改造成矿带,古老俯冲带经燕山期改造/叠加成矿是钦杭成矿带的重要成矿机制。     

A new species of Taxodioxylon from the Lower Cretaceous of the Jixi Basin, eastern Heilongjiang, China

Newly discovered silicified wood from the Jixi Basin, Heilongjiang Province, northeast China, represents the first record of Taxodioxylon sensu Gothan from the Lower Cretaceous of China. Taxodioxylon szei sp. nov. is characterized by abundant wood parenchyma, uniseriate rays 1–50 cells in height, 1–2 rows of separately or contiguously arranged bordered pits, taxodioid-type pits in cross field, no normal resin canals and an absence of spiral thickenings in tracheids. It agrees well with the diagnostic characters of Taxodioxylon, but is distinguished from previously described species by higher rays, the presence of idioblasts in some rays, and by having black granules, which seem to be clusters of a needle-like substance (crystals?) in axial wood parenchyma cells, and traumatic resin canals. The anatomy of T. szei, and other palaeobotanical and sedimentological evidence indicate that the Early Cretaceous climate of the Jixi Basin was seasonal and very favourable to tree growth.     

国外末次冰期极盛期以来陆地植物花粉研究主要进展

近20年来，国外对晚冰期和全新世陆地植物花粉的研完取得了一系列重要进展，主要体现在方法的改进，时间分辨能力的提高，植物对气候响应敏感性的研究，以及区域古环境复原等几个方面。对此做了初步介绍和评述。     

青岛花岗岩类复式岩基的古化石热水体系研究

对青岛花岗岩类复式岩基的氧同位素研究表明，各个岩体的氧同位素组成明显受水岩相互作用的影响。根据样品采集位置和氧同位素分析结果，可以恢复其中六个古化石水体系，它们包括两种类型；内高外低型和内低外高型，其形成可能与当时大气降水的循环方式密切相关，。近模拟计算表明，发生水岩作用的温度多在２５０－４００℃之间，水岩比的变化较大（０．０８％－０．３％）。研究还发现，曾发生过强烈去气作用的岩体与未经去气（或气     

吉林省大黑山条垒中部早二叠世地层的发现及其意义

在吉林省梨树县孟家岭一带，于前人所划属的石炭纪磐石组砂岩、板岩、灰岩中发现丰富动植物化石。经鉴定有Ｈｕｓｌｅｄｉａｃｆｇｍｎｄｉｃｏｓｌａ，Ｓｔｅｎｏｓｃｉｓｍａｓｐ．，Ｃｏｍｐｓｏｐｔｅｒｉｓｓｐ．，其中植物与我国北部和西伯利亚等地区的安格拉植物群相当；从腕足、苔藓虫等化石组合上看均为早二叠世常见分子。大黑山条垒中部的这一首次发现，对吉林省的地层划分、分区及对比具有重要意义。     

Rapid response of forested vegetation to multiple climatic oscillations during the last deglaciation in the northeastern United States

Isotopic and pollen results from a marl lake (White Lake) in the Mid-Atlantic region of USA indicate the coupling of climate and vegetation changes. Oxygen isotopes of calcite from this site show multiple oscillations at millennial and centennial scales, including the Younger Dryas with 3‰ negative shifts in δ¹⁸O at 12.4-11.4 ka (1 ka = 1000 cal yr BP) and three cold events of magnitude 1-2‰ shifts during the Bølling-Allerød warm period (BOA) at 14.3-12.4 ka. Pollen data from the same core show nearly synchronous, close correspondence with isotope-inferred climate shifts, indicating rapid forest response to deglacial climate oscillations in southern New England. A plateau-like BOA is similar to other records around the North Atlantic Ocean.