Abstract The Rollrock Section in the Sverdrup Basin of Arctic Canada is one of the northernmost outcrops where the Jurassic-Cretaceous transition is accessible. The over 500 m thick sedimentary succession exposes the Oxfordian to Valanginian Ringnes and Deer Bay formations. Macrofauna from 15 discrete horizons includes ammonites, Buchia bivalves and belemnites. These fossils improve the biostratigraphy of the Tithonian and Berriasian in the Sverdrup Basin, provide correlation to the remainder of the Boreal Realm and set reliable calibration points. The occurrence of Buchia rugosa in the Ringnes Formation moves the upper formation boundary from the top of the Kimmeridgian into the lower Tithonian. Dorsoplanites maximus and D. sachsi document the middle Tithonian Dorsoplanites maximus Zone in Arctic Canada for the first time. The late Tithonian to early Berriasian Buchia terebratuloides is considered to be the best approximate indicator of the Jurassic-Cretaceous transition in the Rollrock Section. The middle early Berriasian Praetollia maynci and the late early Berriasian Borealites fedorovi tie the respective horizons to the successive Chetaites sibiricus and Hectoroceras kochi zones. Two species of the belemnite Arctoteuthis, collected from an interval with common glendonites, suggest a Valanginian age for the upper Deer Bay Formation. The dearth of Late Jurassic to earliest Cretaceous macrofossils in the Sverdrup Basin is inferred to be predominantly a function of diagenetic carbonate loss. Abundant dropstones and glendonites in the middle Tithonian to middle Valanginian interval suggest cold climatic conditions, and make the Rollrock Section a prime candidate for studying the Arctic environmental perturbations of this time.

中文翻译：

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加拿大北极群岛埃尔斯米尔岛北部 Rollrock 剖面的大型动物群和生物地层学——侏罗纪 - 白垩纪过渡的综合高纬度档案

摘要 加拿大北极Sverdrup盆地的Rollrock剖面是最北端的露头之一，可进入侏罗纪-白垩纪过渡。超过 500 m 厚的沉积层序将牛津阶暴露于 Valanginian Ringnes 和鹿湾地层。来自 15 个离散层的大型动物群包括菊石、Buchia 双壳类和箭石。这些化石改善了 Sverdrup 盆地 Tithonian 和 Berriaasian 的生物地层学，提供了与北方王国其余部分的相关性，并设置了可靠的校准点。Ringnes组中Buchia rugosa的赋存使上层边界从Kimmeridgian顶部移入下Tithonian。Dorsoplanites maximus 和 D. sachsi 首次记录了加拿大北极地区的中间 Tithonian Dorsoplanites maximus 区。晚 Tithonian 到早 Berriasian Buchia terebratuloides 被认为是 Rollrock 剖面侏罗纪-白垩纪过渡的最佳近似指标。中早期 Berriasian Praetollia maynci 和晚期早期 Berriasian Borealites fedorovi 将各自的地层与连续的 Chetaites sibiricus 和 Hectoroceras kochi 区联系起来。从与普通菱镁矿的间隔收集的两种箭石Arctoteuthis 表明上鹿湾组的Valanginian 时代。据推测，斯沃卓普盆地晚侏罗世至最早的白垩纪大型化石的缺乏主要是由于成岩碳酸盐流失所致。提通阶中期至瓦兰吉阶中期丰富的落石和菱镁矿表明寒冷的气候条件，