Is there any way to detect mass file deletion in Sharepoint in Office 365?

Did you see these https://blogs.office.com/en-us/2018/04/05/defend-yourself-from-cybercrime-with-new-office-365-capabilities/, which is a step in the right direction for this sort of thing but not exactly what you're after.

"OneDrive scans files on download for known threats, provides file versioning for all file types, and sends notifications if a mass file deletion is detected."

Great if this could be brought to libraries, where mass anomalies are flagged to admins.   

Saying all that, check out https://support.office.com/en-gb/article/overview-of-office-365-cloud-app-security-81f0ee9a-9645-45ab-ba56-de9cbccab475, which has https://support.office.com/en-gb/article/anomaly-detection-policies-in-office-365-cloud-app-security-88935b4e-dcb1-47f1-8aca-1bf8fb069db6like 'unusual file deletion activity' that can alert on suspicious activities.  This comes at an additional cost unless using E5.