Abstract Climate instability driven by emission of volatiles during emplacement of large igneous provinces (LIPs) is frequently invoked as a potential cause of mass extinctions. However, documenting this process in the geologic record requires a holistic understanding of eruption rates, the location of eruptive centers, and potential sources of climate-changing volatiles. We present new chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon geochronology from Malwa Plateau basalts on the northern margin of the Deccan LIP, India. These basalts have been previously interpreted as either an extension of the province's main volcanic stratigraphy or as an independent eruptive center active up to millions of years prior to the main eruptive phase. Our data instead demonstrate that the lower Malwa Plateau basalts are temporally correlative with the first pulse of Deccan volcanism and provide new constraints on its initiation and duration. Paleomagnetic data further indicate that upper Malwa Plateau basalts may be age-equivalent to the second, third, and fourth pulses of Deccan volcanism. The relative thicknesses of age-equivalent packages of basalt are consistent with eruption of the Deccan LIP from a southward-migrating eruptive center. The first eruptive pulse is coeval with a ∼200 kyr Late Maastrichtian warming event preserved globally in contemporaneous stratigraphic sections. We propose that the first pulse of Deccan magmatism was more voluminous in the north, where it erupted through organic-rich sedimentary rocks of the Narmada-Tapti rift basin. Thermal metamorphism of these sediments could have been a source of sufficient CO2 to drive the Late Maastrichtian warming event, which if true would reconcile the apparent dampened warming signals associated with later Deccan eruptive pulses.

中文翻译：

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印度马尔瓦高原德干大型火成岩省最早喷发的 U-Pb 锆石年龄限制

摘要 在大型火成岩省 (LIP) 就位期间由挥发物排放引起的气候不稳定经常被认为是大规模灭绝的潜在原因。然而，在地质记录中记录这一过程需要全面了解喷发率、喷发中心的位置以及气候变化挥发物的潜在来源。我们展示了来自印度德干 LIP 北缘马尔瓦高原玄武岩的新化学磨损-同位素稀释-热电离质谱 (CA-ID-TIMS) U-Pb 锆石年代学。这些玄武岩以前被解释为该省主要火山地层的延伸，或者是在主要喷发阶段前数百万年活跃的独立喷发中心。相反，我们的数据表明，较低的 Malwa 高原玄武岩与德干火山活动的第一个脉冲在时间上相关，并为其开始和持续时间提供了新的限制。古地磁数据进一步表明，上马尔瓦高原玄武岩的年龄可能与德干火山作用的第二、第三和第四次脉冲相同。玄武岩年龄等效包的相对厚度与从南移的喷发中心喷发的德干 LIP 一致。第一次喷发脉冲与大约 200 kyr 的晚马斯特里赫特变暖事件同时发生，该事件在同期地层剖面中保存在全球范围内。我们认为德干岩浆活动的第一次脉冲在北部更大，在那里它通过纳尔马达-塔普蒂裂谷盆地的富含有机物的沉积岩喷发。